Dissertações/Teses

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2022
Descrição
  • FABIO DE OLIVEIRA TORRES
  • Optimized allocation of radio resources in B5G/6G networks: Sustainable frameworks
    supported by an ensemble of meta-heuristics and a hyper-heuristic

  • Orientador : ROBERTO CELIO LIMAO DE OLIVEIRA
  • Data: 19/12/2022
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  • Optimized allocation of radio resources in B5G/6G networks: Sustainable frameworks
    supported by an ensemble of meta-heuristics and a hyper-heuristic
    RESUMO EM INGLÊS: From the moment that the infrastructures of the fifth generation networks of mobile
    communication (5G) started to be constituted as a commercial reality, the academy and the
    telecommunications sector began to conjecture about the development of technologies that could support
    the next generation, that is, networks beyond 5G (B5G) or sixth generation (6G). Among the objectives
    proposed for these environments, we can mention the offering of a high level of quality of experience to
    the users of these infrastructures through the efficient and personalized allocation of radio resources, such
    as the electromagnetic spectrum and transmission powers. Furthermore, this task must have high
    standards of energy efficiency. However, because current radio resource allocation techniques do not
    consider intrinsic characteristics of B5G/6G scenarios, there is a need to develop new tools that can assist in
    the execution of this task. Additionally, due to the B5G/6G scenarios being designed to be highly dynamic,
    this fact makes it difficult to apply static solutions in these environments. For these reasons, the use of
    algorithms that implement computational intelligence techniques, one of the areas of artificial intelligence,
    to control the distribution of radio resources in B5G/6G networks has become plausible. However, based
    on the "No Free Lunch" theorem, translated as "No free lunch", the application of a single heuristic or
    meta-heuristic in the search for good solutions tends to present good performance only for a certain class
    of problems. In this way, supported by the high data processing power expected to be used in B5G/6G
    networks, the application of a set of algorithms to help control the distribution of some radio resources, in
    which their elements work concurrently or alternately, has become a good option. This thesis proposes two
    new frameworks dedicated to maximizing throughput, energy efficiency indices, and the quality of
    experience offered to users of B5G/6G scenarios. To achieve these goals, the frameworks perform the
    distribution of bands of the electromagnetic spectrum to the communication devices of a B5G/6G network
    and allocate transmission power levels that will be used in the base stations. The difference between the
    frameworks is presented in the application scenarios of each one and by the computational intelligence
    techniques applied in the transmission power allocation task, as one makes use of an ensemble of meta-
    heuristics (EM) and the other of a hyper-heuristic (HH). These two techniques, when compared to others offer the highest level of quality of experience to network users and still perform their tasks with a significant increase in the energy efficiency of the entire system.

  • MARCOS EDUARDO COELHO GARCIA
  • EQUAÇÕES SEMI-ANALÍTICAS PARA PROJETAR ANTENAS DIPOLO DE GRAFENO EM TERAHERTZ SOBRE SUBSTRATO DE VIDRO

  • Orientador : RODRIGO MELO E SILVA DE OLIVEIRA
  • Data: 15/12/2022
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  • Neste trabalho, é desenvolvida uma formulação semi-analítica para auxiliar no processo de projeto de antenas dipolos retangulares baseadas em grafeno com substratos de vidro. A formulação fornece diretamente o comprimento do dipolo necessário para obter ressonância em uma frequência desejada, uma vez que a largura da antena e o potencial químico das folhas de grafeno são conhecidos. Usando o método das Diferenças-Finitas no Domínio do Tempo (Finite-Difference Time-Domain: FDTD), foi realizado um grande número de simulações computacionais considerando várias combinações de dimensões de antena e valores de potencial químico, para obter os valores de referência. A formulação é baseada em: lei de escalonamento eletrostático, cálculo da constante de fase plasmônica, capacitância entre eletrodos metálicos e cálculo de suas auto-indutâncias. O método dos mínimos quadrados é aplicado para otimizar os coeficientes da formulação. Com os coeficientes otimizados, foram obtidos níveis de precisão muito satisfatórios. No intervalo de frequências entre 0,5 THz e 3,0 THz, o erro médio relativo absoluto é de 1,50%, com um erro relativo absoluto máximo de 6,77%.

    Publicação:

    GARCIA, M. E. C. ; DE OLIVEIRA, RODRIGO M. S. ; RODRIGUES, N. R. N. M. . Semi-analytical Equations for Designing Terahertz Graphene Dipole Antennas on Glass Substrate. Journal Of Microwaves, Optoelectronics and Electromagnetic Applications, v. 21, p. 11-34, 2022.

    http://dx.doi.org/10.1590/2179-10742022v21i11335

  • JOSÉ ALANO PERES DE ABREU
  • APPLICATIONS OF ESTIMATORS OF STOCHASTIC STATES AIDED BY ARTIFICIAL NEURAL
    NETWORKS IN TRACKING AND IMPROVING THE PREDICTION OF THE POINT OF IMPACT OF BALLISTIC
    ROCKETS

  • Orientador : ROBERTO CELIO LIMAO DE OLIVEIRA
  • Data: 02/12/2022
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  • One of the current ways to continue space research is to launch ballistic rockets that
    carry scientific payloads. To improve the accuracy of the instantaneous evolution of the payload impact on
    the Earth's surface, it is necessary to estimate the indirect measures of velocity of a space vehicle more
    efficiently. In this thesis a broader approach is proposed to determine the impact point prediction of
    ballistic rocket payloads. This approach combines tracking algorithms based on stochastic estimators aided
    by artificial neural network (ANN) models to predict the rocket's trajectory and consequently predict its
    impact point. Initially, four stochastic estimators existing in the literature were implemented as tracking
    algorithms, namely, a recursive Kalman filter (RKF), an extended Kalman filter (EKF), an unscented Kalman
    filter (UKF) and a particle filter ( PF). Then, these existing estimators were compared with four proposed
    stochastic estimators. These include a recursive Kalman filter aided by an ANN (RKFN), an extended Kalman
    filter aided by an ANN (EKFN), an unscented Kalman filter aided by an ANN (UKFN), and a particle filter
    aided by an ANN (PFN). Finally, this study shows that the results obtained using the proposed tracking
    algorithms RKFN, EKFN, UKFN, and PFN are better than the existing tracking algorithms RKF, EKF, UKF, and
    PF. The proposed estimators can be an efficient and low-cost tool to mitigate modeling inaccuracies during
    the tracking of the ballistic rocket until the impact of its payload.

  • BRUNO GOMES DUTRA
  • METHODOLOGIES FOR REAL TIME FORCE AND MOVEMENT CONTROL OF MULTIFUNCTIONAL MYOELECTRIC HAND PROSTHESIS.

  • Orientador : ANTONIO DA SILVA SILVEIRA
  • Data: 02/12/2022
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  • The loss of an upper limb incapacitates an individual to do functions of grip and manipulate objects, causing disorders and limiting the capacity to do daily tasks. Therefore, in this work it is proposed a complete control system for multifunctional myoelectric hand prosthesis with the user. The proposed system presents one superior layer of decision-making, an inferior layer of prosthesis actuators control, and the integration logic of layers. In the superior layer, it is realized both the classification of 8 movements of the hand and the estimation of the grasping force. In the inferior layer, two control loops are implemented with the predictive controller MPCSS, one for the prosthesis fingers’ angular control position, and the other to control the grasping force of it. The integration logic runs intuitively to control the prosthesis, according to the user’s grasping force and movements patterns. For the development of the proposed system, this work investigated the methods of real-time classification with the neural networks MLP and ELM, and the Machine learning techniques of the KNN and SVM types. To estimate the user’s grasping force, a model in the state space with Kalman filter is proposed. In the control layers, it is utilized a multivariable predictive controller in state space formulation to control the angular position model and the grasping force model of the prosthesis. Furthermore, in the grasping force control loop, it is proposed the application of the Kalman filter to estimate and filter the system’s global force, by sensor fusion of sensors placed in the prosthesis fingers. The performance of the system was evaluated with data recorded from ten experimental healthy subjects. In the classification results, it was shown that the most viable technique and with the best performance was the SVM, that obtained a mean accuracy and  of 97%. The estimation force model, proposed in the state space with Kalman Filter, presented a Pearson’s correlation coefficient, R^2, of 0.92 ± 0,0318, and a NRMSE index of 0,277 ± 0,056, demonstrating good performance and a better option in comparison with other models previously seen in the literature. The proposed control loops presented robust performance indices and precision in the tracking of both angular position and force control. Furthermore, the Kalman filter presented in the force control loop enhanced the stability and the system performance to hold objects. The proposed system runs in real-time with a mean processing time less than 300 ms, does the classification of 8 patterns of movements of the hand, estimates the user's force, and executes the commands of gesture and force in the prosthesis similarly to the dexterity of the human hand.

     

    Keywords: multifunctional prosthesis, real-time control, movement classification, Kalman filter, predictive control, linear regression, machine learning.

  • WESLLEY LEAO MONTEIRO
  • AVALIAÇÃO DE DESEMEPNHO OPERACIONAL DE MICROGERAÇÃO E MINIGERAÇÃO SOLAR FOTOVOLTAICA E EDIFICAÇÕES COMERCIAL E PÚBLICA NO ESTADO DO PARÁ

  • Orientador : WILSON NEGRAO MACEDO
  • Data: 18/11/2022
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  • AVALIAÇÃO DE DESEMEPNHO OPERACIONAL DE MICROGERAÇÃO E MINIGERAÇÃO SOLAR FOTOVOLTAICA E EDIFICAÇÕES COMERCIAL E PÚBLICA NO ESTADO DO PARÁ

  • ULISSES CARVALHO PAIXÃO JUNIOR
  • METODOLOGIA PARA DESENVOLVIMENTO E GESTÃO DE COMUNIDADES DE ENERGIA, COM ESTUDO DE CASO NA UNIVERSIDADE FEDERAL DO PARÁ

  • Data: 04/11/2022
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  • Vários países do mundo iniciaram a transição energética utilizando geração distribuída com fontes renováveis e sistemas de armazenamento com baterias, para proporcionar eficiência energética, flexibilidade, segurança operacional, sustentabilidade e redução de custos com energia elétrica. Monitoradas e gerenciadas por um sistema de gestão, as novas tecnologias têm trazido empoderamento ao cotidiano do consumidor, de modo que este possa participar ativamente das decisões de oferta e de demanda de energia em seu convívio individual ou em grupo. Sob a ótica do consumidor, este trabalho apresenta uma metodologia para desenvolvimento e gestão de uma comunidade de energia, operando com geração híbrida de energia elétrica, advinda da rede externa e da geração fotovoltaica, e sistemas de armazenamento. Dada suas características e seu perfil de cidade, um estudo de caso com dados reais do sistema de distribuição do campus da Universidade Federal do Pará (UFPA) é considerado e os sistemas fotovoltaicos e de armazenamento são modelados, com base em uma abordagem probabilística, de acordo com a irradiação solar da região e a demanda de energia da Universidade. A operação do sistema é gerenciada durante o período de doze meses, para simular as características, limitações e particularidades da comunidade de energia. Como conclusão do trabalho, é apresentado o retorno do investimento da comunidade de energia implementada na UFPA, evidenciando a possibilidade de escalabilidade de um novo modelo de negócio.

     

  • MARIA DA PENHA DE ANDRADE ABI HARB
  • AN ANALYSIS OF THE DELETERIOUS IMPACT OF THE INFODEMIC DURING THE COVID-19 PANDEMIC IN BRAZIL: A CASE STUDY CONSIDERING POSSIBLE CORRELATIONS WITH SOCIOECONOMIC ASPECTS OF BRAZILIAN DEMOGRAPHY

  • Data: 04/11/2022
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  • Humanity has suffered, throughout its history, from the various epidemics of infectious diseases. For example, black plague, yellow fever, cholera, HIV, among others. During this time, the processes of globalization, together with advances in medicine and technology, have changed the way these pandemics are experienced. With the speed that information travels, the internet has become an important source of research for users all over the world. Currently, a new coronavirus (called Sars-Cov-2) originating in China, has caused the biggest pandemic experienced in the age of technology. In the appearance of an unknown (or little known) disease, the population searches for information related to the disease, such as symptoms, preventive measures, government actions. The researched data can generate a pattern on the behavior of the population and are used to predict and model epidemics, becoming powerful resources to analyze the conduct of individuals in a country. In the current scenario, the World Health Organization (WHO) has declared that it is fighting not only against an international epidemic, but also against an infodemic in social networks and information media. Studies show that research related to COVID-19 skyrocketed as the pandemic was developing. At first, little information was known about the virus, which generated doubts in the population, as well as uncertainties in the information found. The rapid advance of the disease and its consequences and the huge amount of poorly structured information, some of which was misinformation, exposes network users to the myriad of sources of information, increasing the likelihood of also finding false news and disinformation, as well as sharing the same. Thus, it can interfere positively or negatively in the advance of the pandemic. Understanding this aspect of the pandemic is interesting to make it necessary to adopt timely and effective actions to determine what types of responses and control and prevention measures should be required by authorities, researchers. Thus, in this scenario, this thesis proposal presents a model using machine learning techniques to measure the impact of infodemic on the population, using the Covid-19 pandemic in Brazil as a case study.

  • NELSON MATEUS FERREIRA SANTOS
  • PROJETO DE FSS EM 3,5 GHZ USANDO ALGORITMO BIO-INSPIRADO: UMA ABORDAGEM COM REDE NEURAL OTIMIZADO COM O ALGORITMO SAILFISH MULTIOBJETIVO

  • Data: 17/10/2022
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  • Este trabalho aborda uma técnica de otimização multiobjetivo híbrida bioinspirada, associada a uma rede neural de regressão geral como proposta para sintetizar a geometria e dimensões de uma superfície seletiva de frequência (FSS), para filtragem de ondas eletromagnéticas em aplicações 5G. Essa nova técnica híbrida associa o algoritmo bio-inspirado conhecido como Sailfish Optmizador (SFO), em conjunto de uma rede GRNN para a obtenção dos parâmetros de construção do filtro. Neste estudo o foco é destinado na aplicação do da técnica como ferramenta para o projeto e síntese da FSS, sendo ela com a forma de uma espira quadrada na célula unitária, impressa em uma placa de substrato de fibra de vidro (FR4). Os objetivos do processo de otimização consistem em ajustar a frequência ressonante do FSS para 3,5 GHz e a largura de banda de operação de 0,8 GHz. Uma Boa concordância entre os resultados simulados e medidos é relatada.

  • FERNANDO DUARTE BRITO
  • Avaliação Probabilística da Capacidade da Hospedagem Combinada de Microgeradores Fotovoltaicos e Veículos Elétricos em Redes de Distribuição de Baixa Tensão Considerando o Efeito do Controle Volt-Var: Um Estudo de Caso

  • Data: 27/09/2022
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  • Avaliação Probabilística da Capacidade de Hospedagem Combinada de Microgeradores Fotovoltaicos e Veículos Elétricos em Redes de Distribuição de Baixa Tensão Considerando o Efeito do Controle Volt-Var: Um Estudo de Caso

  • LUANA OLIVEIRA DE ALBUQUERQUE
  • YIELDS ASSESSMENT THROUGH THE CONFIGURATION OF LOAD CONTROLLERS OF ISOLATED PHOTOVOLTAIC SYSTEMS CONNECTED TO A DIRECT CURRENT DISTRIBUTION NANONETWORK

  • Data: 09/09/2022
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  • This work evaluates the yields of photovoltaic generators, using different configurations of control in load controllers used in isolated systems, being these controllers interconnected, forming a nanogrid of distribution in direct current. It contextualised the uses of microgrids and the presentation of the nanogrid used, which is installed in the laboratory of the Group of Studies and Development of Energy Alternatives (GEDAE) of the Federal University of Pará. Throughout the work, the main equipment responsible for the formation of a network in this type of system are indicated, being the load controllers, associated with energy storage systems and photovoltaic generators. In this sense, different configurations from those recommended by the manufacturers are adopted, but within acceptable limits, to increase the productivity of photovoltaic generators and thus increase the autonomy of energy storage systems. According to the results obtained, when only one generation and storage system was in operation, an increase in generation productivity was observed; when analyzing the nanogrid with all systems in operation, with different configurations, an increase was observed, however, it was difficult to identify, due to the exchange of energy present in the nanogrid, making it more advantageous to choose a single configuration for all systems.

  • RITA DE CÁSSIA PORFÍRIO DA CUNHA
  • Metaheuristics for BBU-RRH mapping and load balancing between BBUs applied to Centralized Access Networks.

  • Data: 19/08/2022
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  • The growing demand for information access, generated by multimedia applications, is one of the challenges of the new generation of mobile networks. The fifth generation (5G) aims to meet increasingly stringent user requirements, such as latencies and low power consumption. One of the proposed architectures to supply the demands that arise with 5G and to support this traffic is the Cloud Radio Access Network (C-RAN), which centralizes processing power to solve the load imbalance, allocate resources accordingly based on network demand. This architecture proposes resource sharing while addressing processing scalability issues. Recently,
    metaheuristic optimization algorithms have been widely used to solve problems of this nature. Meta-heuristic algorithms are used because they are more powerful than conventional methods, which are based on formal logic or mathematical programming, in addition to the fact that the time required for execution is less than that of exact algorithms. In this context, the objective of this study is to develop an optimized resource allocation model that performs load balancing between Baseband Units (BBUs) and Remote Radio Heads (RRHs), based on the Particle Swarm Optimization (PSO) method. For this purpose, a variation of the PSO algorithm, the Discrete Particle Swarm Optimization (DPSO) was used, which optimizes the proposed objective function. Results point to superior performance of this objective function in comparison to the proposed benchmarking, both in high and low traffic densities.

  • MELLINA MODESTO LISBOA
  • ANÁLISE DE DESEMPENHO DE PARA-RAIOS DE ZNO SOB DIVERSOS CENÁRIOS DE POLUIÇÃO UTILIZANDO MÉTODO DE ELEMENTO FINITOS 

  • Data: 16/08/2022
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  • O para-raios de Óxido de Zinco é um dos dispositivos de proteção de vital importância para os Sistemas Elétricos de Potência e os equipamentos que os compõe, uma vez que ele assegura a confiabilidade e a continuidade de operação desses sistemas a partir da sua capacidade de atenuar as sobretensões transitórias resultantes de descargas atmosféricas ou surtos de manobra. Esse equipamento é formado por blocos de resistores variáveis de ZnO, associados em série ou em paralelo, cuja curva de tensão-corrente apresenta alta não-linearidade. Tendo em vista a relevância da utilização do para-raios, faz-se necessária a investigação das condições de operação deste. Na literatura, são encontrados diversos procedimentos e técnicas destinadas a tal finalidade, entre as quais destaca-se o monitoramento por meio da medição e análise da corrente de fuga, dado que esta representa um dos fatores principais que contribuem para a degradação deste equipamento. Diante deste contexto, a presente dissertação de mestrado implementa um modelo bidimensional de um para-raios de Óxido de Zinco de 30 kV, utilizando o Método de Elementos Finitos, para obter-se as curvas da corrente de fuga, as distribuições do potencial elétrico, da densidade de corrente e a das linhas de campo elétrico, quando este dispositivo se encontra sujeito às condições de variações de tensão e poluições. Os resultados mostram um aumento das grandezas adquiridas(que aumento? Quais grandezas?) à medida que o nível de poluição se intensifica, bem como, com o aumento dos níveis de tensão.

  • MARCO ANTONIO LOUREIRO LIMA
  • COVID-19 SEVERITY CLASSIFICATION AND ANALYSIS USING MACHINE LEARNING.

  • Data: 16/08/2022
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  • In the last years, with the alarming growth of COVID-19 cases, a highly contagious viral disease, new forms of diagnosis and control for this sickness have become necessary to the spread decreases until the population is effectively vaccinated. In this context, Artificial Intelligence (AI) and its subfields appear as possible alternatives to help and provides a response to combat the virus. Some Machine Learning (ML) methods are shown as an answer to control this disease, these methods can perform an analysis based on a set of symptoms presented by the patient and consequently indicating the diagnosis, as well as streamline the treatment process. To achieve this goal in this paper, three models that uses ML methods to predict COVID-19 severity on different degrees are proposed, unlike other works whose purpose was to diagnose only the presence or absence of Covid-19, this paper aims to improve the classification of the patient's disease state. The results in each of these models are evaluated through the metrics established in this work. Furthermore, there are distinct suggestions to improve the analysis and make predictions with greater  accuracy.

  • FABIO ANTONIO DO NASCIMENTO SETUBAL
  • IDENTIFICAÇÃO DE FORÇA A PARTIR DE DADOS DE VIBRAÇÃO USANDO A METODOLOGIA DE SUPERFÍCIE DE RESPOSTA EM CONJUNTO COM O ALGORITMO DE REGRESSÃO DE FLORESTA ALEATÓRIA

  • Data: 11/08/2022
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  • Em muitos projetos dinâmicos e de diagnóstico de falhas de estruturas mecânicas, é necessário o conhecimento da força externa atuante. No entanto, a medição dessas forças muitas vezes é difícil ou impossível de ser realizada e, nesse caso, um problema inverso deve ser resolvido. Este artigo propõe um método de identificação de força usando a Metodologia de Superfície de Resposta com base em Design Composto Central em conjunto com o algoritmo de Regressão de Floresta Aleatória. Esse procedimento requer, inicialmente, o modelo modal em elementos finitos da estrutura forçada. Em seguida, análises harmônicas são realizadas, variando os parâmetros de forças e, então, aplica-se a Metodologia de Superfície de Resposta para a geração de um conjunto de dados contendo os valores de amplitude, frequência e localização das forças, além dos valores de aceleração de vibração em vários pontos da estrutura. Este conjunto de dados foi utilizado para treinar e testar um modelo de Regressão de Floresta Aleatória utilizado para predizer qualquer localização, amplitude e frequência da força a ser identificada, tendo como informações somente a aquisição da vibração em determinados pontos da estrutura. Os resultados numéricos mostraram excelente precisão na identificação da força aplicada à estrutura.

  • KALEF LEVY DE LIMA PINTO
  • SENSOR DE DEFORMAÇÃO DE SPECKLEGRAMA DE FIBRA ÓPTICA BASEADO EM APRENDIZADO PROFUNDO

  • Orientador : JOAO CRISOSTOMO WEYL ALBUQUERQUE COSTA
  • Data: 08/08/2022
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  • SENSOR DE DEFORMAÇÃO DE SPECKLEGRAMA DE FIBRA ÓPTICA BASEADO EM APRENDIZADO PROFUNDO

  • LUÍS AUGUSTO MESQUITA DE CASTRO
  • CONTRIBUTIONS TO THE GENERALIZED MINIMUM VARIANCE CONTROL: UNRESTRICTED HORIZON PREDICTIVE CONTROL

  • Data: 04/08/2022
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  • This work investigates the unrestricted horizon predictive controller, or UHPC. It is designed via state space using the GMVSS method and based on the ARMAX linear model. Its control law is implemented in the RST polynomial controller format for the control of monovariable systems with the objective of carrying out robustness and performance analyzes, consolidating UHPC as a member of the predictive controllers. The proposal presents in detail all the mathematical formalism necessary for a good understanding of the designs of the GMV and UHPC controllers, both in the polynomial and state space approach. The GMVSS design method is based on the premise that the complexity of the controller structure is dictated by the complexity of the design model, with the most significant contribution to design simplicity due to the absence of Diophantine equations in the procedure. Diophantine equations are solved indirectly and naturally by the problem formulation itself, using the Kalman filter obtained from a stochastic representation in the state space. Predictive controllers can be based on ARMAX or ARIMAX models, employing the cost function in positional or incremental form, including or not a weighting filter in the system output. This work also explains how to obtain the RST controller structure from the UHPC control law. In addition, the inheritance of tuning of the PID and IPD controllers for the GMV and UHPC controllers is presented, as well as the inclusion of the weighting filter in the control project, which allows to inherit the dynamic characteristics of any linear controller or even to perform the GMV and UHPC design via pole placement. Finally, the synthesized control law is applied to different classes of linear and non-linear systems through numerical simulations and practical tests, evaluating the characteristics of robustness and performance of the proposed controller via sensitivity functions, Nyquist diagram, map of poles and zeros, small gain theorem and performance indexes from reference tracking tests and disturbance rejection. The results obtained demonstrate that the predictive controller UHPC can deal with model plant mismatches and external noise, contributing positively to the stability margins of the control system.

    Keywords: Unrestricted horizon predictive controller. Predictive and stochastic control. Generalized minimum variance in the state space. Reference tracking. Disturbance rejection. Robustness analysis.

  • LEONARDO NUNES GONCALVES
  •  Software para Planejamento de Redes IoT: Uma solução baseada em Algoritmo Genético, Algoritmo de Múltiplas Tentativas e EPSO

  • Data: 20/07/2022
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  • The Internet of Things (IoT) allows the ubiquitous monitoring of environments through sensors arranged in a certain area of interest. Such data collection generates unprecedented content of information that is presented to different algorithms that serve to assist in decision-making associated with economy, health, well-being, among others. To ensure the success of this communication chain, defined from the collection of data to the extraction of valuable decisions, it is necessary to implement an end-to-end communication. For this, the IoT makes use of the Long-Range communication technology (LoRa), which in turn guarantees wireless and cost-free communication between the sensors installed in the endnodes arranged in the area of interest and the data traffic aggregation points installed in the area to be monitored, ie the gateway. Although the solution is practical, it generates the challenges of minimizing the costs associated with the implementation of the smallest number of gateways in the area to be covered, as well as the task of planning the IoT network taking into account the optimal positioning of the gateways. Given this context and to respond to the challenges imposed by the planning of IoT networks, this work aims to propose an optimizing software for planning IoT networks based on Genetic Algorithm, Evolutionary Particle Swarm Optimization (EPSO) and Multiple Trials algorithm, in order to to minimize the number of gateways and determine the geolocation for their installation, thus aiming to guarantee the coverage of all endnodes and their respective sensors arranged in the field.

  • JOINER DOS SANTOS SA
  • DESENVOLVIMENTO DE SOFTWARES E ALGORITMO BASEADO EM REDES NEURAIS ARTIFICIAIS PARA SUPORTE À GESTÃO DA MOBILIDADE URBANA EM SMART CAMPUS COM CARACTERÍSTICA MULTIMODAL

  • Data: 20/07/2022
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  • This work presents the development of two software solutions and an algorithm based on artificial neural networks to support the management of urban mobility in a smart campus. The first software, called Norte Rotas, is a web solution whose objective is to support the planning of pedestrian routes, providing relevant information about the physical conditions of the routes of a smart campus. The second solution is an Android mobile software that aims to manage transport modes present in a smart campus. Tests in simulated and real environments were carried out and the results indicate that the proposed tools are good solutions for the planning and management of modal routes in an intelligent university campus. In addition to the software, a computational intelligence algorithm is proposed to determine the best travel route considering the options on foot, by bus and by boat in an IoT system of a smart campus. Data were collected from UFPA's Circular bus routes, and tests with different parameters of an ANN were performed. The results indicate that the RNA-based solution is promising to be implemented in urban mobility aid systems.

  • SUZANA CESCON DE SOUZA
  • Analyses of EEG Oscillatory Actives During Cognitive Training Using Holo-Hilbert
    Spectral Analysis

  • Data: 19/07/2022
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  • In this work we developed a protocol for the analysis of a cognitive training
    (TC), in order to raise the performance in bulldozer operators of Vale S.A. This research took part
    of the POAD (High performance operator’s program) Innovation Project of the Vale
    Technological Institute (ITV). The protocols of the TC were based in Neurofeedback (NFB), in
    order to develop the ability to self-regulate cerebral frequencies, based on
    electroencephalogram (EEG) analysis. In this research, the Holo-Hilbert Spectral Analysis (HHSA)
    for the study of amplitude modulation (AM) band frequency (FM) of the rhythms that compose
    the cerebral frequencies. The HHSA was based on empirical mode decomposition (EMD) in two
    layers. First the EEG signal has been decomposed in a series of intrinsic mode function in
    modulated frequency (IMFs) and then every IMF modulated in frequency have been

  • JORGE LUIZ MOREIRA PEREIRA
  • EFEITOS HARMÔNICOS DEVIDO A ALTA PENETRAÇÃO DE GERAÇÃO FOTOVOLTAICA EM SISTEMAS DE DISTRIBUIÇÃO

  • Data: 29/06/2022
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  • EFEITOS HARMÔNICOS DEVIDO A ALTA PENETRAÇÃO DE GERAÇÃO FOTOVOLTAICA EM SISTEMAS DE DISTRIBUIÇÃO

  • MATIAS RIBEIRO MÁXIMO DE LAVÔR
  • BALANÇO ENERGÉTICO DE UM LABORATÓRIO DE PESQUISA EM CENÁRIOS PRÉ, DURANTE E PÓS PANDEMIA, VISANDO CERTIFICAÇÃO DE NZEB.

  • Data: 27/06/2022
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  • Sistemas de geração solar fotovoltaica desempenham um papel essencial para a melhoria da eficiência energética de uma edificação. Nesse sentido, o presente estudo busca apresentar uma análise de balanço energético em diferentes cenários cronológicos para o prédio do Centro de Excelência em Eficiência Energética da Amazônia - CEAMAZON, entidade pública de Pesquisa, Desenvolvimento e Inovação, vinculada à UFPA, localizado no Parque de Ciência e Tecnologia Guamá. Além disso, é realizada uma breve análise em relação ao novo INI-C relacionada à metodologia de avaliação nZEB, com recente implantação de sistema de geração distribuída, destacando o conjunto de características da edificação que possam classificar sua eficiência energética e demonstrando parâmetros essenciais para certificação.

  • WENDRIA CUNHA DA SILVA
  • Numerical Analysis of a Graphene Surface Plasmon Resonance Sensor in Terahertz.

  • Data: 24/06/2022
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  • This work proposes a Terahertz plasmonic refraction index sensor based on Single-Layer Graphene operating as a refractometer in the Terahertz range. The configuration used is Kretschmann, where one of the variables that monitors the reflectivity is the chemical potential. The sensor was theoretically analyzed by the finite element method (FEM), modeling in a two-dimensional structure. In it, reflectivities and field distributions were calculated for different parameters, such as thickness, frequency, angle and permittivity. Firstly, a study was made to determine the best operating frequency, angle of incidence and minimum sample thickness. After that, the numerical model was compared with the analytical one. From the numerical results, parametric analyzes were performed to verify variations in sensitivity, full width at half maximum (FWHM) and resolution, all parameters of device quality. Numerical results are compared with theoretical concepts available in the literature and in recently published works.

  • EMERSON SANTOS DE OLIVEIRA JUNIOR
  • Procedural Generation of Realistic Synthetic Data for Training Machine Learning
    Models: Application on precision agriculture based on drone images

  • Data: 21/06/2022
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  • This work aims to present the implementation of a framework capable of synthesizing
    data for machine learning models, demonstrate results obtained with semantic segmentation networks
    trained with these synthetic data, and describe preliminary results that exemplify how this methodology
    allows segmentation to be used for classification. In this work, the amount of weeds that infest certain
    areas in planting zones were classified. The methodology takes advantage from the deep convolutional
    neural networks, performing pixel-level calculations in the images to determine infestation percentages
    and estimating when the network does not correctly define the amount of weeds in its predictions.

  • IGOR RODRIGUES DE NARDI
  • PROTEÇÃO DE SISTEMAS DE CARREGAMENTO DE VEÍCULOS ELÉTRICOS CONTRA DESCARGAS ATMOSFÉRICAS

  • Data: 13/06/2022
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  • À medida que os veículos elétricos e as energias renováveis se expandem, surge
    também a necessidade de investigar novos métodos de proteção contra raios para essas novas tecnologias. Esse trabalho tem como objetivo avaliar a performance de sistemas de carregamento de veículos elétricos frente às descargas atmosféricas durante seu regime transitório. Modelos de duas estações de carregamento, uma conectada à rede de energia CA e a outra desconectada, foram utilizados nas análises. Além disso, um modelo impulso de tensão proveniente de descargas atmosférias foi usado. Os resultados deste trabalho demonstraram as alterações nas formas de onda de tensão na entrada e na saída dos circuitos, sendo possível avaliar quais pontos são mais vulneráveis, necessitando de maior proteção. Além disso, foi avaliado se dois eletropostos do Centro de Excelência em Eficiência Energética da Amazônia – CEAMAZON – estão adequadamente protegidos contra descargas atmosféricas. Para isso, tomou-se como base os estudos realizados na Ásia, Europa, além da norma brasileira. Constatou-se que, apesar do prédio do CEAMAZON possuir um SPDA adequado, os eletropostos encontram-se vulneráveis, sobretudo contra os efeitos indiretos causados pela ocorrência de descargas atmosféricas nas proximidades dos eletropostos.

  • ANDRE FELIPE SOUZA DA CRUZ
  • Electromagnetic Analysis and Modeling of Plasmonic Sensors Operating in Optical and Terahertz Ranges: Solutions by Generalized Coefficients and Green's Functions

  • Data: 20/05/2022
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  • In the present work, the modeling of equivalent electromagnetic structures is presented, used in the analysis and description of the response of plasmonic sensors operating in the optical and terahertz (Far Infrared) ranges. Simulations were carried out to evaluate the electromagnetic response of four sensors, which operate according to the Surface Plasmon Resonance (SPR), and Surface Plasmon Coupled Emission (SPCE) phenomenon, these are: SPCE THz sensor based on DLG (Double-Layer Graphene); Kretschmann THz sensor based on MLG (Multi-Layer Graphene); Gold-based SPCE Optical Sensor; and SLG/Gold based Kretschmann Optical Sensor. The electromagnetic description of the sensors was performed by combining analytical models derived from the Multimodal method, where it is possible to calculate the intensity of the EH (Electric and Magnetic) fields, due to the incidence of a plane wave in a multilayer structure, and from the Out-of-Phase Periodic Green’s Function method, which uses the spectral representation of the EH fields, by the complex Fourier series, over the Floquet modes. In terahertz sensors, graphene is modeled as a surface impedance described by the Kubo model. In optical sensors, graphene and gold are characterized as materials of finite thickness and complex refractive index (RI), both experimental values made available by Laboratório de Síntese e Caracterização Laser de Nanomateriais, at Puc-Rio. The results show the EH field profiles in the structure of plasmonic sensors. In the analysis of the PGF of the SPCE Thz sensor, we verified the appearance of symmetrical and asymmetrical plasmonic poles in the spectral representation of their EH fields. For the Kretschmann THz sensor, we verified a sensitivity S=2.42°RIU −1 for the case with three graphene layers, in addition to a FWHM (Full Width at Half Maximum) of 5.75° for the case with five graphene layers. For the optical SPCE sensor, it was verified that the SPCE excitation occurs for the monochromatic laser source with an incidence ≥ 30◦. Finally, for the SPR sensor based on SLG/Gold, there was an increase of 2% in sensitivity when compared to the case without graphene.

  • CARLINDO LINS PEREIRA FILHO
  • AVALIAÇÃO DA ESTRUTURA TARIFÁRIA  BRASILEIRA  COM CONTRIBUIÇÕES DE PONTOS PARA REVISÃO

  • Data: 20/05/2022
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  • A disponibilidade a energia elétrica é indispensável para garantia da dignidade humana no século XXI. Ela é essencial em atividades domésticas e econômicas, a prova está na existência da correlação entre nível de desenvolvimento e consumo per capita de energia elétrica. Em função da importância da eletricidade, a estrutura tarifária de um país deve buscar o equilíbrio entre o interesse de consumidores e empresários. Na estrutura tarifária brasileira as empresas são extremamente protegidas dos riscos de negócio, por outro lado, os consumidores cativos não têm liberdade de escolha na aquisição e são obrigados a pagar pelos riscos das empresas. Este trabalho almeja propor mudanças na estrutura tarifária brasileira para que todos os consumidores possam ter mais direitos e pagar por uma tarifa de energia elétrica mais justa. Para isso é exposto um panorama geral do setor elétrico brasileiro e a estrutura tarifária vigente, que são comparados com países membros do BRICS e OCDE. Observou-se por meio de dados de tarifa de energia e socioeconômicos, que componentes da formação do valor da tarifa fazem com que consumidores de estados mais pobres tenham que pagar tarifas de energia mais altas. Esse acréscimo no preço da energia faz com que a competitividade para atração de empreendimentos de regiões pobres seja menor, o que contribui para aumento de desigualdades entre estados. Um modelo voltado para o setor industrial de incentivos de eficiência energética é proposto como atração para investimento em práticas mais sustentáveis e melhoria na formação tarifária. Por fim, são propostas mudanças nas opções de modalidade tarifária em componentes que compõem a tarifa de energia e critérios de qualidade exigidos.

  • SILVIO DOMINGOS SILVA SANTOS
  • All-dielectric metasurfaces based on trimers with toroidal dipole modes

  • Data: 19/05/2022
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  • In this work, it is proposed and studied all-dielectric metamaterials composed by square, rectangular, rhomboidal and hexagonal unit cells based on trimers. These metamaterials are all-dielectric periodic planar arrays of dielectric disks on a dielectric substrate, which are able to sustain two types of toroidal dipole orders (called toroidal - TO and antitoroidal - ATO), that are differentiated by the distribution of toroidal dipole moments in the trimers (symmetric and asymmetric, respectively). The structures, as well as the resonance modes, were analyzed theoretically by using group theory techniques, symmetry-adapted linear combination method (SALC), magnetic dipole moments approximation and circuit theory, for the numerical simulations was used the commercial Comsol Multiphysics software. In particular, a new theoretical approach is proposed to understand the excitations of symmetry-protected toroidal modes, through the so-called magnetic groups. The theoretical and numerical results were validated through microwave experiments in the 8 - 15 GHz range, with good agreement of the results. Due to the unique configuration of the fields of these modes strongly confined in the proposed metasurfaces, they can be considered as an efficient light-matter interaction platform for next generation technologies, with regard to enhanced absorption, non-linear switching, (bio-)sensing and in other applications of photonics.

  • LUISE FERREIRA CARDOZO
  • Robust Control Techniques based on Frequency Response and Interval Pole Placement for Systems with Parametric Uncertainties applied to the voltage regulation problem in Power Converters

  • Data: 12/05/2022
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  • Microgrids are a form of distribution system, which belong to the broad concept of smart grids. Multiconverter or multilevel systems are nothing more than DC microgrids composed of several power converters connected in cascade and/or in parallel. In this way, the multiconverter system described in this thesis has a DC - DC converter in the Buck topology, which is used as a source of direct voltage for the main bus of the microgrid, being an element of fundamental importance and whose voltage control is essential, because electronic loads are sensitive to voltage deviations. In order to control the voltage on the DC bus, the system is first modeled using the recursive least squares method, at which time the parametric variations are obtained forming a more comprehensive model called the interval transfer function, which is represented graphically by the extreme set. In a second moment, two robust controllers are developed, one through the extreme stability margins of the model culminating in a PI controller based on frequency response, and the other through an interval pole allocation control project in PID format. The robust performance of the controllers is evaluated through computational simulation, experimentally in the multiconverter system and, finally, using a quantitative analysis through performance indices.

  • RICHARDSON SALOMÃO DE ARAÚJO
  • DIMENSIONAMENTO, SIMULAÇÃO E ANÁLISE ECONÔMICA DE UM SISTEMA FOTOVOLTAICO CONECTADO À REDE COM ARMAZENAMENTO DE ENERGIA

  • Data: 29/04/2022
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  • DIMENSIONAMENTO, SIMULAÇÃO E ANÁLISE ECONÔMICA DE UM SISTEMA FOTOVOLTAICO CONECTADO À REDE COM ARMAZENAMENTO DE ENERGIA

  • WANDERLEY SENA DOS SANTOS
  • MODELAGEM DE SISTEMAS FOTOVOLTAICOS DE BOMBEAMENTO DE ÁGUA E DESENVOLVIMENTO DE UM CONVERSOR DE FREQUÊNCIA PARA ESTA APLICAÇÃO ESPECÍFICA

  • Data: 11/04/2022
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  • MODELAGEM DE SISTEMAS FOTOVOLTAICOS DE BOMBEAMENTO DE ÁGUA E DESENVOLVIMENTO DE UM CONVERSOR DE FREQUÊNCIA PARA ESTA APLICAÇÃO ESPECÍFICA

  • IGOR MEIRELES DE ARAUJO
  • VIRTUALIZAÇÃO DE FUNÇÕES DE REDE: ENCADEAMENTO DE SERVIÇOS E PROCESSAMENTO DE PACOTES EM GPU

  • Data: 01/04/2022
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  • O crescimento da demanda da internet tem impulsionado o desenvolvimento de novas arquiteturas de infraestrutura de rede como o network function virtualization (NFV). Nesta arquitetura, as funções de redes são separadas do hardware e implementadas via software de forma que seja executas em um hardware genérico  através de tecnologias de virtualização. Essa nova infraestrutura traz maior flexibilidade além da redução de custos de operação e aquisição comparada com a infraestrutura tradicional composta por middleboxes (dispositivo com hardware proprietário para execução de específica função de rede). Um serviço de telecomunicação é uma funcionalidade ponta-a-ponta oferecida aos usuários pelas operadoras de rede, geralmente consiste em várias funções de rede encadeadas em uma ordem específica. O processo para a construção dessas cadeias é conhecido como service function chaining (SFC). Com a flexibilidade do NFV, as funções de redes podem ser implantadas de forma escalável, remotamente e durante a operação da rede aumentado a complexidade do SFC além de que para garantir a confiabilidade dos serviços às vezes é necessária a realização de SFC para recursos de reserva (backup). Uma outra consideração em relação ao NFV, é o desempenho da função de rede. Espera-se que as funções implementadas via software tenham pelo menos o mesmo desempenho ou melhor do que as presentes em middleboxes. Entretanto, com a migração de um hardware específico para um genérico com propósitos gerais, possibilita a utilização de outros hardware que também vem sendo utilizado para propósitos gerais como as graphic processing units (GPUs). Diante do exposto, esta tese investiga dois pontos do NFV, a confiabilidade e o desempenho. O primeiro ponto foca na topologia de rede como um todo e na otimização de recursos no encadeamento de serviços garantindo a confiabilidade do serviço. Enquanto o segundo ponto foca no desempenho de uma única função de rede virtualizada utilizando processamento paralelo em GPU para reduzir o tempo de processamento de pacotes e consequentemente aumentar o throughput da rede.
  • MARINALDO DE JESUS DOS SANTOS RODRIGUES
  • METODOLOGIAS DE AVALIAÇÃO DE GERADORES FOTOVOLTAICOS EM SITUAÇÃO DE SOMBREAMENTO PARCIAL 

  • Data: 31/03/2022
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  • METODOLOGIAS DE AVALIAÇÃO DE GERADORES FOTOVOLTAICOS EM SITUAÇÃO DE SOMBREAMENTO PARCIAL 

  • ALAN SOVANO GOMES
  • Modeling and Robust Parametric Control Applied to Driven-Right-Leg Systems for Noise Rejection in Biopotential Amplifiers

  • Data: 30/03/2022
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  • The Driven-Right-Leg (DRL) system is widely applied to mitigate the effects of common mode voltage in biopotential amplifiers. It works as a closed-loop controller, whose objective is to reject disturbances caused by the capacitive coupling of the patient with the power line. In this work, the DRL system is evaluated from a robust parametric control point of view, with the intention of doing a more complete evaluation than the one found in the literature, measuring gain, phase and module extremal margins. The range of interval parametric variations, found in the literature, were used to describe the parametric uncertainties that disturb the studied system. Furthermore, a Lead-Lag controller was designed based on the model under parametric variation obtained, showing how both the analysis and synthesis of DRL controllers can be done with the presented theory. The results obtained were discussed in comparison with the DRL systems found in the specialized literature.

  • LUIZ EDUARDO SALES E SILVA
  • ANÁLISE PROBABILÍSTICA DO IMPACTO TÉCNICO-ECONÔMICO DAS CONEXÕES DE MICROGERADORES FOTOVOLTAICOS E VEÍCULOS ELÉTRICOS EM REDES DE DISTRIBUIÇÃO DE BAIXA TENSÃO

  • Data: 18/03/2022
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  • ANÁLISE PROBABILÍSTICA DO IMPACTO TÉCNICO-ECONÔMICO DAS CONEXÕES DE MICROGERADORES FOTOVOLTAICOS E VEÍCULOS ELÉTRICOS EM REDES DE DISTRIBUIÇÃO DE BAIXA TENSÃO

  • MARKOS PAULO CARDOSO
  • Plasmonic multi-resonance sensors using D-type photonic crystal fibers

  • Data: 14/03/2022
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  • This thesis proposes an excitation scheme for multiple plasmonic resonances along the optical spectrum for use in the monitoring refractive index and to enabling the determination of the dispersion properties of the analyzed medium. The sensing configuration consists of a D-type photonic Crystal fiber whose flat face is partially covered by distinct metallic layers. Using simulations based on Finite Element Method, it is possible to demonstrate how to customize plasmon resonances at different wavelengths, allowing to measure with low cross-talk more than one parameter in a simple and direct way, such as the mean refractive index and the first or second order optical dispersion. The central aspect of this sensing configuration is to balance miniaturization with low coupling between the different localized plasmon modes in adjacent metallic nanostructures. Furthermore, the determination of the optical dispersion of a given medium in a large spectral range provides information about the concentration of the medium constituents, which is of crucial importance for the monitoring of media in real-time, such as fluids.

  • ELEN PRISCILA DE SOUZA LOBATO
  • IMPLANTAÇÃO DE UM MIDDLEWARE IOT ESCALÁVEL PARA APLICAÇÕES DE MOBILIDADE ELÉTRICA MULTIMODAL

  • Data: 25/02/2022
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  • IMPLANTAÇÃO DE UM MIDDLEWARE IOT ESCALÁVEL PARA APLICAÇÕES DE MOBILIDADE ELÉTRICA MULTIMODAL

  • ALEXANDRE DE SOUZA BRASIL
  • ADEQUAÇÃO DO LABORATÓRIO DE ALTA TENSÃO DA UFPA - LEAT AOS REQUISITOS GERAIS PARA A COMPETÊNCIA DE LABORATÓRIOS DE ENSAIO E CALIBRAÇÃO DA NORMA ABNT NBR ISO/IEC 17025

     

  • Data: 24/02/2022
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  • Fenômenos que desequilibrem o sistema elétrico de potência ocorrem constantemente, o que gera a necessidade de estudá-los com o objetivo de permitir o desenvolvimento de redes e equipamentos elétricos que se comportem de forma mais confiável e robusta diante de tais distúrbios. Estes estudos são, em geral, realizados em laboratórios especializados de Alta Tensão e Alta Potência. No decorrer dos anos, o mercado passou a demandar que estes estudos também fornecessem resultados que cumprissem padrões de qualidade certificados por órgãos oficiais. Nesse sentido, esta dissertação objetiva propor a adequação necessária do Laboratório de Ensaios em Alta e Extra Alta Tensão da Universidade Federal do Pará aos requisitos para a competência de laboratórios de ensaio e calibração definidos pela norma ABNT NBR ISO/IEC 17025, com foco no desenvolvimento e implantação de um Sistema de Gestão da Qualidade; criação de procedimentos operacionais e diretrizes de segurança; estabelecimento de um programa de calibração para os equipamentos do laboratório; e identificação das motivações, vantagens e impactos relacionados a implementação dos requisitos da referida norma, bem como as dificuldades e soluções encontradas. Para isso, primeiramente foi realizado um levantamento literário que buscou conhecer o panorama nacional de instituições de ensino superior com laboratórios acreditados sob a referida norma. Em seguida, iniciou-se o processo de implementação dos requisitos da norma, o qual se baseou na metodologia adaptada de Grochau (2011). Por fim, a experiência vivenciada permitiu observar que a adequação aos requisitos da norma em laboratórios vinculados a instituições públicas, apesar de complexa em um primeiro momento, é plenamente capaz de proporcionar diversos benefícios e vantagens, desde que sejam respeitadas as peculiaridades deste tipo de instituição como: burocracia; limitação de recursos; capacitação do pessoal envolvido e; conciliação das atividades de pesquisa e ensino com a prestação de serviço.

     

    Artigos Publicados:

    BRASIL, A, S; BRASIL, F, S; MANITO, A, R, A; NUNES, M. V. A. Processo de Acreditação de um Laboratório de Ensaios em Alta Tensão conforme a ABNT NBR ISO/IEC 17025: Implantação de um Sistema de Gestão da Qualidade e Calibração de Equipamentos. In: VIII Simpósio Brasileiro de Sistemas Elétricos 2020 (SBSE 2020). Santo André – SP.

     

    BRASIL, A, S; BRASIL, F, S; MANITO, A, R, A; NUNES, M. V. A. Gestão de Segurança em Alta Tensão – Adequação à NR 10: Segurança em Instalações e Serviços em Eletricidade do Laboratório de Ensaios em Alta Tensão da UFPA. ISO/IEC 17025: Implantação de um Sistema de Gestão da Qualidade e Calibração de Equipamentos. InVIII Simpósio Brasileiro de Sistemas Elétricos 2020 (SBSE 2020). Santo André – SP.

     

  • MARCEL AUGUSTO ALVARENGA VIEGAS
  • ESTAÇÃO SUSTENTÁVEL E INTELIGENTE DE CARREGAMENTO RÁPIDO DE VEÍCULOS ELÉTRICOS

  • Data: 24/02/2022
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  • ESTAÇÃO SUSTENTÁVEL E INTELIGENTE DE CARREGAMENTO RÁPIDO DE VEÍCULOS ELÉTRICOS

  • DIEGO BRANCHES VILAR
  • ESQUEMA DE TARIFAÇÃO DINÂMICA DE ENERGIA PARA PROGRAMAS DE RESPOSTAS À DEMANDA CONSIDERANDO A INTEGRAÇÃO DE FONTES DE ENERGIA RENOVÁVEIS

  • Data: 22/02/2022
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  • ESQUEMA DE TARIFAÇÃO DINÂMICA DE ENERGIA PARA PROGRAMAS DE RESPOSTAS À DEMANDA CONSIDERANDO A INTEGRAÇÃO DE FONTES DE ENERGIA RENOVÁVEIS

  • RONILSON WILLIAME DA SILVA PEREIRA
  • QOE ASSESSMENT FOR VIDEO STREAMING OVER DUAL CONNECTIVITY 5G MMWAVE OVERHEAD NETWORKS

  • Data: 18/02/2022
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  • The evolution in mobile telecommunications has allowed the emergence of new network formats aimed at meeting the growing demand for wireless data, mainly fueled by more video content viewing. The scarce spectrum available on current cellular networks does not seem to be able to handle this explosion of wireless data, prompting a shift to explore new frequency bands. The communication of millimeter waves (mmWave), frequency bands, between 30 and 300 GHz appears as an essential part for the next generation of fifth-generation (5G) cellular networks, as they adopt higher carrier frequencies offering high width bandwidth, lower latency. However, system performance degrades due to high propagation loss and the sensitivity of the links to obstacles. To mitigate such factors, this dissertation proposes a dual connectivity 5G mmWave architecture using LTE (Long Term Evolution) and the use of UAVs (Unmanned Aerial Vehicles) as airbase stations to provide connectivity and guarantee experience quality in video streaming. Through simulations, an analysis of the Quality of Experience (QoE) about the transmission of 4K videos was presented with the objective of evaluating the transmission and quality of the videos perceived by users. The simulated results show the efficiency of the system for multimedia applications using videos, improving the QoE of wireless users by 43%.

  • VITOR HUGO MACEDO GOMES
  • ANALYSIS OF FACTORS RELATED TO THE PERFORMANCE INDEX OF SCHOOLS IN THE IDEB: A CASE STUDY IN THE STATE OF PARÁ

  • Data: 11/02/2022
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  • The complexity of identifying all the factors that are related to the performance of schools on the Basic Education Development Index (IDEB) is enormous. In this study, three databases were analyzed in order to identify several factors that correlate with low performance in state schools in the state of Pará. This study used educational data mining techniques to first select variables with structural characteristics in the teaching environment, comparing schools with higher and lower performance in IDEB identifying possible relationships with school dropouts. Then, the Randon Florest (RF) algorithm was used to select the most important variables that directly or indirectly impact the IDEB index. After the selection phase, the variables were submitted to the Linear Regression (LR) algorithm. The results point out that the income of students is related to the average family income in the analyzed municipalities. Next, variables related to parents' income were used to identify possible relationship between parents' schooling and students' performance. Finally, the analysis ends with the analysis of the impact of the Municipal Human Development Index (HDI) on the variables related to the students' grade, qualification, and experience of the teachers in the school environment. The results reveal that there is a correlation between the index and student learning in the classroom. On the other hand, better indexes in IDEB are directly related to the adequacy of the curriculum to the subject taught, as well as good working conditions for teachers. This study sought, through the MDE, to unveil different factors that are related to the low performance of state schools in the state of Pará. It shows that the socioeconomic situation of families who have children of school age is not only detrimental to the performance of these students, but also to their permanence in the classroom. Therefore, there must be a greater engagement of schools to stimulate the interest of students to persist in the school environment. In addition to subsidies from the government so that teachers can fully exercise their role in society.

  • RAPHAELE SAMUA BARATA GOMES
  • DIAGNÓSTICO DE EFICIÊNCIA ENERGÉTICA COM BASE NO INI-C E RTQ-C: ESTUDO DE CASO DA ENVOLTÓRIA DO CLUBE DE CIÊNCIAS DA UFPA

  • Data: 09/02/2022
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  • Poupar energia tornou-se urgente e não está relacionado apenas à redução de custos, apesar de ser um ponto muito apelativo para os investimentos de empresas. Enxergamos uma crescente “popularização” do uso alternativo de energia e isso se dá devido aos impactos causados pela queima de combustíveis fósseis que, além de emitirem gases poluentes apresentam grande instabilidade energética devido às variações bruscas de preços dos derivados de petróleo (LAMBERTS,2004). Diversos acordos e tratados foram feitos entre os países desde a década de 1970 afim de reduzir os impactos do consumo de energia e, devido as edificações serem responsáveis por cerca de 60% do consumo global de eletricidade, segundo o Programa das Nações Unidas para o Meio Ambiente (PNUMA), surgiu programas e medidas de incentivos para esse setor. No Brasil, surgiu em 2001 o Programa Brasileiro de Etiquetagem (PBE) do Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), com o objetivo de testar e classificar eletrodomésticos, eletrônicos, veículos e mais produtos dentro de 24 categorias, de acordo com sua eficiência energética. A etiquetagem de energia de edifícios no Brasil, especifica os requisitos técnicos, métodos de classificação de edificações energeticamente sustentáveis e existe uma regulamentação para edifícios comerciais, de serviços e públicos e, outra para edifícios residenciais (BRASIL, 2010). O Regulamento Técnico da Qualidade para o Nível de Eficiência Energética de Edificações Comerciais, de Serviços e Públicas (RTQ-C) estabelece critérios e métodos para avaliação e classificação de edificações comerciais, de serviços e públicas quanto à sua eficiência energética visando à etiquetagem dessas edificações. O INMETRO aprovou no dia 09 de março de 2021 a nova Instrução Normativa para a Classificação de Eficiência Energética de Edificações Comerciais, de Serviços e Públicas (INI-C) que aperfeiçoa o RTQ-C. Neste estudo, avaliou-se a envoltória através do método simplificado do INI-C e através do método prescritivo do RTQ-C, da edificação do Clube de Ciências da UFPA a fim de comparar seus resultados e identificar as diferenças na atualização do regulamento. 

  • PEDRO BAPTISTA FERNANDES
  • PLANEJAMENTO DE TRAJETÓRIA PARA ROBÔS MÓVEIS AUTÔNOMOS APLICANDO UM ALGORITMO DE OTIMIZAÇÃO POR ENXAME DE PARTÍCULAS COM PICOS DE DIVERSIDADE


  • Data: 08/02/2022
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  • PLANEJAMENTO DE TRAJETÓRIA PARA ROBÔS MÓVEIS AUTÔNOMOS APLICANDO UM ALGORITMO DE OTIMIZAÇÃO POR ENXAME DE PARTÍCULAS COM PICOS DE DIVERSIDADE

  • DENNER FELIPE SILVA FERREIRA
  • ELECTRONIC TRANSPORT IN 1D SYSTEM WITH COUPLING ATOMIC-SIZE NICKEL ELECTRODES AND CARBON WIRES

  • Data: 31/01/2022
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  • The miniaturization limits foreseen for silicon-based electronic components have mobilized research for alternative materials, so carbon-based structures, due to their versatility, have gained greater prominence. Among the components, carbon-based atomic wires are seen as promising materials, due to the promise of performance and electronic, thermal and magnetic properties. In this context, this work investigated electronic transport using ab initio/Non-Equilibrium Green Function methodology through one-dimensional (1D) junctions with atomic-size diameter based on Cn carbon chains (n from 1 to 10) between semi-infinite Ni electrodes. Finding then a distinction between parity along the carbon strand, cumulene- and polyynes-type structures form in odd (C2n+1) and even (C2n) carbon chains, respectively. It was found (i) that the maximum conductance occurs at a specific voltage (0.20 V) for both parities; (ii) the conductance for polyynes chains decay (from 151 μS to 125 μS), while cumulene chains increase (from 58 μS to 68 μS); (iii) the transmittance for C2n ≈ 2 × C2n+1, causing high currents in C2n ; (iv) the conductance drop in both chains is seen in the transmittance failure (|0.25 V|); (v) the negative differential resistance (NDR) is shown for C2 (2 to 4) at |0.35 V| and for C10 at |0.40 V| due to degeneracy in LUMO's levels, while C2n+1 exhibits resonance at |0.30 V|; (vi) the structures present the behavior of RTD (Resonant Tunnel Diode) and FET (Field Effect Transistor) devices for C2n and C2n+1 , respectively.

  • FLAVIO HENRY CUNHA DA SILVA FERREIRA
  • INTELLIGENT POSITIONING OF DRONES VIA METAHEURISTIC OPTIMIZATION ALGORITHMS FOR MAXIMIZING SIGNAL COVERAGE AREA IN FORESTED ENVIRONMENTS

  • Data: 31/01/2022
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  • This dissertation aims to provide a metaheuristic approach to drone array optimization applied to coverage area maximization of wireless communication systems, with unmanned aerial vehicle (UAV) base-stations. For this purpose, two types of networks utilizing UAVs have been analyzed: a standard Wi-Fi network operating at 2.4 GHz, and a low-power wireless area network (LPWAN), both considering medium to high-density forest environments.LPWAN are systems designed to work with low data rates but still keep, or even enhance, the extensive area coverage provided by high-powered networks. The type of LPWAN chosen herein is LoRa, which operates at an unlicensed spectrum of 915 MHz, and requires users to connect to gateways in order to relay information to a central server – in this case, each drone in the array has a LoRa module installed to serve as a non-fixated gateway. In order to classify and optimize the best positioning for every UAV in the array, three concomitant bioinspired optimization methods have been chosen: the cuckoo search (CS), the flower pollination algorithm (FPA) and the bat echolocation algorithm (BA). All of these methods have a search space distribution based on Lévy / Mantegna flights, and present distinct performance results for both drone array network cases. Positioning optimization results are then simulated and presented via MATLAB, first for the Wi-Fi network and later for a high-range IoT-LoRa network. An empirically adjusted propagation model with measurements carried out on the UFPA campus was developed to obtain a propagation model in forested environments. Finally, drone positioning utilizing the propagation model corrected with measurements is compared with the positioning using the classical theoretical model, showing that the corrected model is more efficient in representing the forest environment than the classical model usually used in recent publications.

  • JOAO PAULO TAVARES BORGES
  • Hybrid CAVIAR Simulations and Reinforcement Learning Applied to 5G Systems: Experiments with Scheduling and Beam Selection

  • Data: 28/01/2022
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  • Reinforcement Learning (RL) is a learning paradigm suitable for problems in which an agent has to maximize a given reward, while interacting with an ever-changing environment. This class of problem appears in several points of interest in the 5th Generation (5G) and the 6th Generation (6G) of mobile networks. However, the lack of freely available data sets or environments to train and assess RL agents are a practical obstacle that delays the widespread adoption of RL in 5G and future networks. These environments must be able to close the so-called reality gap, where reinforcement learning agents, trained in virtual environments, are able to generalize their decisions when exposed to real, never before seen, situations.
    Therefore, this work describes a simulation methodology named CAVIAR, or Communication Networks, Artificial Intelligence and Computer Vision with 3D Computer-Generated Imagery, tailored for research on RL methods applied to the physical layer (PHY) of the wireless communications systems. This simulation methodology is used to generate an environment for the tasks of user scheduling and beam selection, where, at each time step, the RL agent needs to schedule a user and then choose the index of a fixed beamforming codebook to serve it. A key aspect of this proposal is that the simulation of the communication system and the artificial intelligence engine must be closely integrated, such that actions taken by the agent can reflect back on the simulation loop. This aspect makes the trade-off of processing time versus realism of the simulation, an element to be considered. This work also describes the modeling of the communication systems and RL agents used for experimentation, and presents statistics concerning the environment dynamics, such as data traffic, as well as results for baseline systems.
    Finally, it is discussed how the methods described in this work can be leveraged in the context of the development of digital twins.

  • ALEX SANCHES MACEDO
  • CHANNEL ANALYSIS FOR THE 3.5 GHz FREQUENCY AT AIRPORT

  • Data: 28/01/2022
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  • To meet the steep increase in the consumption of users and equipment connected to a mobile network, several works and researches are being proposed and developed. In Brazil, the arrival of 5G technology is expected from 2022, and which will use the 3.5 GHz frequency band. Since there are few studies available in the literature, regarding the channel behavior, its characterization of the channel is of important relevance. Thus, in this dissertation, a study carried out on the channel analysis for the 3.5 GHz frequency in a large indoor environment is presented, this scenario is in a lobby of the Val de Cans International Airport, in Belém do Pará. The measurement campaign were performed for Line-Of-Sight (LOS) and by means of channel probing the small-scale channel dispersion parameters are extracted. These parameters such as mean delay, delay spread, the coherence band of the channel and the power profile and delays were also verified. The signal was also investigated through Floot-Interception, Close-In models and their variations are applied and analyzed to evaluate the path loss for co-polarization (V-V and H-H) and cross-polarization (V-H and H-V). The methodology applied on a large scale proved to be adequate with the data for other types of environments and other frequencies found in the literature.

  • RICARDO GUEDES ACCIOLY RAMOS
  • ILUMINAÇÃO PÚBLICA COM MEDIÇÃO PONTO A PONTO E GERENCIAMENTO REMOTO: UMA EVOLUÇÃO TECNOLÓGICA SMART

  • Data: 26/01/2022
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  • ILUMINAÇÃO PÚBLICA COM MEDIÇÃO PONTO A PONTO E GERENCIAMENTO REMOTO: UMA EVOLUÇÃO TECNOLÓGICA SMART

  • SAULO JOEL OLIVEIRA LEITE
  • PREDIÇÃO DE SÉRIES TEMPORAIS DA COVID-19: UMA AVALIAÇÃO DOS PREDITORES MLP, LSTM E ARIMA

  • Data: 21/01/2022
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  • PREDIÇÃO DE SÉRIES TEMPORAIS DA COVID-19: UMA AVALIAÇÃO DOS PREDITORES MLP, LSTM E ARIMA

  • SERGIO HENRIQUE MONTE SANTO ANDRADE
  • A SMART HOME ARCHITECTURE FOR SMART ENERGY CONSUMPTION IN A RESIDENCE WITH MULTIPLE USERS

  • Data: 21/01/2022
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  • The Smart Cities Concept proposes that a city that was not endowed with (or almost nothing) technology, modernizes itself through the continuous implementation of Smart Systems in its various sectors. Areas such as Mobility, Urban Planning, Energy (Smart Grid), Health, Education and Environment, are positively impacted in this process through data analysis that comes from the technological implementation, bringing more financial and natural resource savings, comfort and well-being to its population.

    One of the implementations in the context of Smart Cities (SC), which has been gaining more space on the world stage compared to others and also more attention from Big Techs, are residences. These, in addition to the possibility of producing valuable data about their users, they can significantly contribute to energy savings for being one of the largest sources of electricity consumption in cities. These homes, implemented with IoT technologies, gets transformed into Smart Homes (SH), which is a Home concept that have, in their total or partial infrastructure, Home Automation Systems(HAS) that aim to make daily life and residential tasks easier and more comfortable for the residents.

    In this thesis by papers, developments are proposed in the context of SH in the field of Hardware, Software and Data Analysis, which aim at: (i) extracting data and properly selecting them to be used as input in HA Systems, (ii) Identification of Residents through WiFi Antenna Handover, (iii) Identification of Electronics connected to Smart Outlets (Smart Outlets) through NFC (Near Field Communication), in order to develop techniques aimed at saving energy individually for each resident within the residence, minimally impacting their comfort and personal well-being.

2021
Descrição
  • LUIZ FELIPE DE SOUSA
  •  Imputation of missing data in structural integrity monitoring

  • Data: 23/12/2021
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  • A common problem in large data sets is missing information, whether due to failure of capture sensors, loss in transport, or another situation that culminates in data loss. Given this situation, the researcher often disregards the missing data, removing them from the set. However, this exclusion can generate inferences that are not valid, especially if the data that remains in the analysis are different than those excluded. To deal with this problem in Structural health monitoring (SHM) data sets, this work makes use of Recurrent Gated Units (GRU) and Long Term Memory (LSTM) neural networks to perform the imputation task. Of missing data. In a step before imputation, the artificial amputation of the data was performed, assuming the Missing Completely at Random (MCAR) missing data mechanism, in percentages of 25, 50, and 75%. The imputation techniques were evaluated using the Average Absolute Percentage Error (MAPE) metric. Subsequently, the damage detection step was applied, as imputed bases were submitted to the Mahalanobis Square Distance (MSD) and Kernel component analysis (kPCA) algorithms to obtain the detected T1 and T2 error rates. From the results obtained, it was possible to observe that the use of LSTM in data imputation achieved better results than GRU in all amputation rates.  Better  performance can also be noticed in the selection of damage detection, where the imputed bases by LSTM achieve better T1 and T2 error detection results.

  • ADRIANA MEDEIROS PINHEIRO
  • CLASSIFICAÇÃO DE RANSOMWARE UTILIZANDO ALGORITMOS DE MACHINE LEARNING

  • Data: 22/12/2021
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  • CLASSIFICAÇÃO DE RENSOMWARE UTILIZANDO ALGORITMOS DE MACHINE LEARNING

  • ANDERSON JOSE COSTA SENA
  • DESCARGAS PARCIAIS RESOLVIDAS EM FREQUÊNCIA COM BASE EM CONTAGEM
    ESPECTRAL DE PULSOS

  • Data: 16/12/2021
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  •  

    Uma metodologia de classificação de descargas parciais (DPs) com base em contagem espectral de pulsos é proposta e apresentada neste trabalho. Os dados de contagem espectral são processados usando uma técnica proposta (PD Spectral Pulse Counting Mapping - PD-SPCM), que leva a um mapa de descargas parciais resolvidas em frequência (Frequency-Resolved Partial Discharges - FRPD). O mapa proposto é então usado para detecção e classificação de DPs. Neste trabalho, FRPDs de corona e ranhura são apresentados em bandas de frequência de até 500 MHz, obtidos a partir de medições de laboratório realizadas usando duas barras estatóricas de hidrogeradores. Os sinais eletromagnéticos das DPs foram capturados usando uma antena patch e um analisador de espectros. As DPs corona e ranhura foram escolhidas para análise porque uma pode ser classificada equivocadamente como a outra pelo fato delas poderem apresentar mapas semelhantes de DP resolvidas em fase (PRPD) e podem ocupar as mesmas bandas espectrais. Além disso, as DPs corona e ranhura podem ocorrer simultaneamente. Os resultados obtidos mostram que as DPs corona e ranhura podem ser devidamente identificadas utilizando a metodologia desenvolvida, mesmo quando ocorrem simultaneamente e nas mesmas bandas espectrais. Isso é possível porque, como é demonstrado experimentalmente, DPs corona e ranhura têm níveis apreciáveis de contagem espectral de pulsos em bandas particulares do espectro de frequência.



  • FÁBIO VINÍCIUS VIEIRA BEZERRA
  • DETECÇÃO DA DEGRADAÇÃO DE CONTATOS ELÉTRICOS EM BAYS DE SUBESTAÇÕES DE ENERGIA ELÉTRICA VIA ANÁLISE ESPECTRAL DA CORRENTE DE CARGA

  • Data: 16/12/2021
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  • This thesis proposal aims at developing a diagnostic system to detect the current stage of degradation of electrical contacts, with the main goal of implanting a predictive maintenance procedure for sectionalizing switches and circuit breakers in bays of electric transmission/ distribution substations. The main feature of the diagnostic system proposed here, is that it will produce predictive indicators of the degradation stage of electrical contacts for the system under operation, based on the spectral analysis of the load current that is flowing through the contacts, using the signal-to-noise relationship (SNR). Therefore, to implement the proposed diagnostic procedure it is not necessary new investments in measurement equipment, being enough the already existing measurement infrastructure. By implementing the diagnostic system proposed here, electrical utilities will have a modern tool for monitoring their electrical installations, supporting the implementation of new predictive maintenance functions typical of the new scenario of the current electrical smart grids. It will also be used data obtained from laboratory tests for the characterization of frequency signatures for circuit breakers and sectionalizing switches to discovery typical patterns that may indicate the degradation stage of electrical contacts of these components, separately. It will be presented preliminary results obtained by the application of the proposed  technique using real data acquired from a 230 kV substation belong to the utility ELETRONORTE, which indicate the effectiveness of the proposed diagnostic procedure.

  • LENA VEIGA E SILVA
  • STRATEGIES FOR ANALYSIS OF MORTALITY UNDERREPORTING IN EPIDEMICS OCCURRING IN DEVELOPING COUNTRIES: A Case Study of COVID-19 in Brazil

  • Data: 10/12/2021
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  • The impact of epidemics throughout history has been devastating, posing a threat to public health and requiring immediate and effective action by authorities. The consequences are even greater when they are disseminated in underdeveloped or developing countries, resulting in scenarios with high rates of underreporting. Investigation, control, prevention and guidance measures are necessary in an epidemiological scenario. Investigating the behavior of past epidemics using historical time series data can help to define patterns and assist in more realistic predictions of new or known diseases. In this scenario, this thesis presents strategies for the analysis of epidemic underreporting, based on time series, applied in countries with social inequalities, with precarious conditions of health services, inadequate diagnostic network, which have flaws in the dissemination of data related to disease. The strategies are based on time series forecasting models, generated by machine learning techniques, used to predict the expected behavior of epidemic occurrences, revealing outliers, in order to create scenarios closer to reality and provide subsidies to public authorities for decision-making. As a way of showing the effectiveness of the proposal, the COVID-19 pandemic in Brazil is used as a case study.

  • JOSE WELITON DE OLIVEIRA ARAUJO
  • ISOMERIA EFFECTS FOR ELECTRONIC TRANSPORT IN NANODEVICES WITH CARBYNE ELECTRODES

  • Data: 24/11/2021
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  • The field of study focused on nanoscience has developed in the last decades. Theoretical studies on electronic transport modeling in semiconductor organic materials have provided important progress in nanotechnology. Among these molecular materials we highlight a class of compounds formed by carbon atoms with conjugated pi molecules, bipyridine, characterized by two pyridine rings. In this work, we study the properties of electronic transport in molecular junctions formed by bipyridine isomers as the central region and electrodes of carbyne wires. Through calculations of first principles, based on Density Functional Theory (DFT), combined with Non-Equilibrium Green's Functions (NEGF), we obtain important properties such as electric current, differential conductance, transmission and eigenchannels. The results showed that the presence of nitrogen atoms at the molecule-electrode interface strongly affects the coupling of the junction, providing a better electronic conduction, this is corroborated by the transmission eigenchannels. The transport properties analyzed revealed that in bipyridine bridges, devices with carbyne electrodes, presented better performance, when compared to other works that used metallic electrodes (Au, Ag and Cu) or graphene electrodes. The results showed a Field Effect Transistor (FET) behavior when the devices are formed by symmetric isomers, where as for asymmetric systems we obtained characteristics of Molecular Diode (MD).

  • DANIEL LEAL SOUZA
  • Control and Adjustment of Convergence in Classical and Quantum Evolutionary Multi-Swarm Algorithms Based on Fuzzy Systems, Particle Intercommunication between Swarms and Detection of Trajectory Patterns.

  • Data: 11/11/2021
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  • This work presents a set of hybrid metaheuristics, based on the use of evolutionary strategies in conjunction with the classical and quantum particle swarm optimization algorithms under a multi-swarm environment with master-slave topology. In this context, new heuristics are used to control cluster agglomeration and mutation of particle replications (Fuzzy Mamdani inference machine), as well as the use of local search methods with convergence monitoring based on the global best history. The algorithms are called Fuzzy Competitive Evolutionary Multi-Swarm Optimization with Convergence Monitoring (FCEMSO-CM) and Fuzzy Competitive Quantum-Behavior Evolutionary Multi-Swarm Optimization with Convergence Monitoring (FCQEMSO-CM). In order to validate the results, twenty non-restrictive benchmark problems and four engineering problems will be used in several scientific publications: Welded Beam Project (WBD); Minimzation of Weight Tension/Compression Spring (MWTCS); Speed Reducer Design (SRD); Design of Pressure Vessel (DPV). The algorithms are implemented in CUDA massive parallel computing architecture, providing a more adequate data distribution in relation to the organization of the swarms, as well as the significant decrease of the processing time. With the application of the evolutionary strategies in the PSO and QPSO algorithms, as well as the heuristics of agglomeration control and local search based on convergence monitoring, the solutions proposed in this document offer several advantages, such as the improvement in search capacity and control of the convergence rate.

  • SHIRLEY KAROLINA DA SILVA FERREIRA
  • Implicit motor imagery classification based on ERD/ERS of EEG signals

  • Data: 28/10/2021
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  • Motor imagery is a mental task and the Electroencephalography (EEG) signals recorded during this activity can be used to implement brain-computer interfaces, as well as for motor rehabilitation protocols. The most of existing works treats an explicity estimulated motor imagery, in which the subjetcs are instructed to perform the same task in repeated trials. However, the implicity motor imagery classification, engajed from the mental rotation protocol still do not exist in the literature. Therefore, the present work propose the use of two machine learning approaches in the classification of the hand laterality based on hand mental rotation paradigm that stimulates motor imagery process. The data from a rehabilitation electronic game was used to implement the classifier algorithms and the features vectors are the values of ERD and ERS (in dB) extracted from EEG signals. The results shown good performance of the LDA classifier, as well the best setup to implement the classification problem and the influence of the visual stimuli on the classifier performance.

  • FABIO BARROS DE SOUSA
  • Performance Analysis of Communication Systems with Acoustic Optical Filter and Photonic Crystal Fiber for Signal Regeneration.

  • Data: 08/10/2021
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  • Through this work, we sought to investigate the performance of optical fiber communication systems with the aid of signal regeneration techniques, such as 2R (Re-amplification and Reshaping) and 3R (Re-amplification, Re-shaping and Re-timing) based om the non-linear effects of Kerr type: self-phase modulation (SPM), cross-phase modulation (XPM) and four-wave mixing (FWM). For this, the commercial software OptiSystem was used to design three communication systems with Mach-Zehnder interferometer (MZI) architecture composed of an acoustic optical filter (AOF) and highly non-linear photonic crystal fiber (HNL-PCF). The objective was achieved through the interactive search for the solution of the nonlinear Schrödinger equation (NLSE) in which the split step Fourier method (SSFM) was used, where in the simulations the power of the input signal, the link length and the frequency difference between the input and the pump signal were used as figure of merit for the analysis of the performance of the systems proposed for the transmission rate of 10 Gb/s. The results were found as a function of eye diagrams, pulse shapes and optical input and output spectra of the systems, by comparing the values of the quality factor (Q-Factor), the bit error rate (BER), eye height, timing jitter and optical signal-to-noise ratio (OSNR) of the degraded and regenerated signals. Therefore, it can be said that through these projects it was possible to carry out the 2R and 3R all-optical regenerations in a satisfactory manner and with great performance values. In short, this thesis was written and organized using three of the articles published in journals, but with the necessary adaptations, with the chapters, as follows: In chapters 1 and 2, the 2R and 3R regeneration systems based on MZI with AOF and HNL-PCF were presented, respectively, and in chapter 3 the all-optical regeneration systems with hybrid modulation and with on-off keying (OOK) modulation with return to zero (RZ) and nonreturn-to-zero (NRZ) encoding. And finally, in chapter 4, the general conclusion, future works, publications and submissions in journals and conferences, as well as the appendix with prints of articles published in journals as first author and co-author. 

  • VINICIUS BORGES ANDRADE
  • Análise Técnico-Econômica da Inserção de Geração Distribuída Fotovoltaica em Redes de Distribuição: Estudo de Caso do Sistema Elétrico de uma Cidade Universitária

  • Data: 07/10/2021
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  • Com o crescimento do uso de fontes alternativas de energia, há um grande interesse na integração de unidades de geração distribuída (GD), fazendo com que o Sistema Elétrico de Potência (SEP) opere não mais de forma unidirecional, mas sim com um fluxo de potência bidirecional. Por isto, a GD representa grandes benefícios para o sistema elétrico, entre eles estão o adiamento de investimentos em expansão dos sistemas de transmissão e distribuição, o baixo impacto ambiental, a redução no carregamento das redes, a minimização das perdas técnicas, melhoria no perfil de tensão e a diversificação da matriz energética. Sendo assim, devido a este crescimento em redes de distribuição, justificam-se incentivos ao desenvolvimento de ferramentas computacionais que auxiliem em estudos próximos do comportamento real. Portanto, o presente trabalho tem por objetivo analisar os principais impactos em regime permanente da geração distribuída fotovoltaica (GDF) na rede de distribuição da Universidade Federal do Pará (UFPA). Para isto, foi feita uma revisão bibliográfica dos principais estudos envolvendo estes impactos. Em seguida, para a modelagem, escolheu-se o software OpenDSS. Foram determinados os cenários de simulações de penetração de GDF. As análises foram feitas em curvas de carga para um dia útil, sábado e domingo. A aquisição das curvas de carga foi feita através do software Sistema de Gerenciamento de Energia Elétrica (SISGEE), que monitora online grandezas elétricas dos prédios da UFPA, como consumo, potência, tensão, corrente, dentre outras. Para uma análise mais real foram aquisitados dados de temperatura ambiente e irradiância da região de Belém do Pará. Além disto, foram utilizados dados comerciais de um painel fotovoltaico e um inversor. Os resultados mostraram o impacto significativo da inserção de GDF na melhora ou piora do perfil de tensão da rede, resultando em alguns casos de sobretensão, redução ou aumento das perdas técnicas verificadas nas linhas e transformadores, a depender do nível de penetração fotovoltaica e sua localização, além do benefício financeiro e ambiental.

  • WESIN RIBEIRO ALVES
  • Deep Learning Applied to Channel Estimation in MIMO Wireless System

  • Data: 06/10/2021
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  • This work researches and presents the results of investigations on the channel estimation problem in millimeter-wave MIMO wireless systems considering low-resolution analogto-digital converters (ADC). Three channel estimation models based on Deep Learning (DL) are presented: the matched estimation model, the mismatched model, and the Deep Transfer Learning (DTL) based channel estimation. DL models use Convolutional Neural Networks (CNN) to extract attributes from the databases generated by Raymobtime methodology for Beijing and Rosslyn scenarios. In the experiments performed in this thesis, “pilots” signals were transmitted and used as input to the DL models, which returned the estimated channel matrix as output. In total, six different experiments were carried out. The first experiment made a comparison between the matched, mismatched and DTL models alternating the scenarios of Beijing and Rosslyn as data source. The second compared different channel generation procedures including models that performed a post-processing in the ray-tracing (RT) simulations, those that incorporated MIMO antenna arrays in the RT simulations, and those that used random parameters to generate channels. The third experiment did a detailed investigation about the channel generation procedure with random parameters. The fourth considered data augmentation technique to train channel estimation models. The fifth compared model variations considering multimodal data available in Raymobtime. The sixth and last experiment compared the model proposed in this thesis with the model based on conditional Generative Adversarial Networks (cGAN). The results of these experiments highlight that the model based on DTL has a lower computational cost compared to the one using DL. Regarding the Raymobtime methodology, incorporating MIMO antenna arrays within RT simulations produces more favorable scenarios for the channel estimation task. Considering the results obtained, as a general conclusion of the thesis, it is observed the great importance of the methodology adopted to evaluate the channel estimation techniques that are based on machine learning. For example, the way channel matrices are generated greatly influences the results of experiments, along with the definition of training and test sets.

  • PITTHER NEGRÃO DOS SANTOS
  • Optimizationof Modified Yagi-Uda Nanoantenna Arrays Using Adaptive Fuzzy GAPSO

  • Data: 01/10/2021
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  • This work presents an optimization of radiation characteristics and absorption of modified Yagi-Uda (YU) nanoantennas. Four antenna geometries are considered: conventional YU powered by voltage source and transmission line, and YU with a loop element powered by voltage source and transmission line. The four proposed geometries are by inserting and combining new elements with different spacings and sizes. Initially, the mathematical modeling of these antennas was performed via linear Moment Method (MoM) to determine the directivity, gain, input impedance and radiation efficiency. Then this modeling was used simultaneously with the optimization method called Fuzzy Adaptive AGPSO, which is the result of hybridization between the genetic algorithm (AG) and particle swarm optimization (PSO), with a fuzzy system used to adapt some parameters of the latter. This hybrid method was used to find the best spacings between the elements and their lengths in such a way as to obtain better directivity, gain,  efficiency and input impedance. Optimized results show that modified YU nanoantennas have better characteristics than conventional YU antennas.

  • ISA CRISTINA CARVALHO DE ANDRADE
  • CRIAÇÃO DE UM MODELO DE CLASSIFICAÇÃO DE TWEETS EM PORTUGUÊS RELACIONADOS A CRIMES UTILIZANDO MÁQUINA DE VETORES DE SUPORTE

  • Data: 24/09/2021
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  • CRIAÇÃO DE UM MODELO DE CLASSIFICAÇÃO DE TWEETS EM PORTUGUÊS RELACIONADOS A CRIMES UTILIZANDO MÁQUINA DE VETORES DE SUPORTE

  • ANDREY KAZUYA NAKAMURA
  • A New Power Allocation Method Using Zero-Forcing Precoding for Cell-Free mMIMO Networks with
    Restricted Fronthaul Capacity

  • Data: 22/09/2021
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  • The fifth generation of mobile communication systems (5G) is a reality, with networks deployed worldwide and 5G-capable devices commercially available. One of its components is CF-mMIMO systems, in which a large number of APs are distributed over the network and serve all UEs simultaneously over the same time-frequency block. To attenuate the interference between the APs, linear precoding schemes are implemented on the network, of which CB and ZF are some of the most common methods, with ZF being the focus of this work. CF-mMIMO has the potential of improving capacity, reliability, and fairness among all users on the network, with the latter often achieved by maximizing the minimum capacity of the users via an optimal power allocation. However, the optimal solution for the power allocation problem is a non-deterministic polynomial (NP)-hard problem, and different strategies were developed to find a suboptimal solution. In this context, the suboptimal solution for the max-min optimization problem is often achieved using the bisection method or heuristic methods. The former has the drawback of a high computational cost, while the latter may not achieve good performances depending on the evaluated metrics. Moreover, the ZF method is a centralized method, meaning the computation of linear precoding and power allocation are done by the CPU. This approach has the drawback of constantly sending CSI data from the APs to the CPU via the fronthaul and may not be scalable when UEs increases significantly. This work proposes a new method to find a suboptimal solution for the max-min optimization problem with lower computational complexity than the bisection method, achieving better results than both the latter and heuristic methods, depending on the metrics evaluated, and also analyzes the performance impact of compressing the CSI.

  • DAVI CARVALHO MOREIRA
  • ANÁLISE DE SOBRETENSÕES TRANSITÓRIAS MUITO RÁPIDAS DURANTE FALHAS EM SUBESTAÇÕES ISOLADAS A GÁS

     

  • Data: 17/09/2021
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  • Esta tese de doutorado desenvolve uma análise de sobretensões transitórias muito rápidas (VFTOs), experimentadas por subestações isoladas a gás (SIGs), que ocasionam falhas de chaves seccionadoras (CSs) e disjuntores (DJs). Um modelo de múltiplas centelhas, para equipamentos de manobras em SIG, foi desenvolvido e proposto para analisar todo o processo de geração de VFTO. As simulações foram implementadas utilizando um programa de transitórios eletromagnéticos, com modelos de circuitos equivalentes para análise de alta frequência. Os parâmetros das VFTOs obtidas nas simulações computacionais, como por exemplo, componentes oscilatórias, valor de pico, tempo de subida e número de oscilações, foram consistentes com as medições de VFTOs realizadas no ensaio em campo, validando a modelagem dos componentes implementados no estudo e permitindo assim uma avaliação consistente da falha. A severidade das VFTOs obtidas por simulação computacional e observadas no DJ, foi considerada alta devido terem apresentados parâmetros consideravelmente maiores que a referência. Os resultados das simulações computacionais, indicaram que as falhas ocorreram em uma tensão abaixo da tensão suportável de impulso atmosférico com uma quantidade elevada de centelhas. Após uma análise completa da falha, considerando os resultados das simulações computacionais, registros de oscilografias e exames visuais, foi possível concluir que o fechamento manual da CS produziu centelhas excessivas e estresses anormais no dielétrico da região do campo elétrico não homogêneo do DJ, impactando desta forma na redução da rigidez dielétrica do gás SF6 até a geração de arco elétrico de alta intensidade entre o anticorona e o invólucro.

    This thesis develops an analysis of very fast transient overvoltages (VFTOs) experienced by gas-insulated substations (GISs) that caused failures in disconnect switches (DSs) and circuit breakers (CBs). A multi-spark modelfor GIS maneuvering equipment was proposed to analyze the entire VFTO generation process. The simulations were implemented using an electromagnetic transient program, with equivalent circuit models for high frequency analysis. The VFTOs parameters obtained in the computer simulations, such as oscillatory components, peak value, rise time and number of oscillations, were consistent with the VFTOs measurements performed in the field test, validating the modeling of the components implemented in the study and thus allowing for a consistent assessment of failure. The severity of the VFTOs obtained by computer simulation and observed in the CB was considered high because they presented parameters considerably higher than the reference. The results of the computer simulations indicated that the failures occurred at a voltage below the withstand voltage of an atmospheric impulse with a high number of sparks. After a complete failure analysis, considering the results of computer simulations, oscillography records and visual examinations, it was possible to conclude that the manual closing of the DS produced excessive sparks and abnormal stresses in the dielectric in the region of the CB inhomogeneous electric field, impacting this form in the reduction of the dielectric strength of the SF6 gas to the generation of a high intensity electric arc between the anticorona and the casing.



     

    Segue o artigo publicado em periódico A1 - Qualis CAPES:

     

    Analysis of VFTO during the failure of a 550-kV gas-insulated substation (MOREIRA et al., 2020). Publicado na revista Electric Power Systems Research (ISSN: 0378-7796 / Qualis CAPES A1 (Engenharia IV): Fator de Impacto 3,211: JCR 2019);


  • ALESSANDRE SAMPAIO DA SILVA
  • ELECTRONIC TRANSPORT IN DOPED CARBON ALLOTROPES

  • Data: 14/09/2021
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  • In this work is presented a theoretical investigation of the electronic transport of a series of two-terminal devices based on doped Phagraphene nanoribbon is presented. The devices were separated into two families of ribbon, whose location of the substitutional doping determines the group, and can be in a central location in the spreading region with -BN or at the zigzag edge terminations with -N. The calculations were based on the hybrid DFT-NEGF methodology implemented in the TRANSIESTA package. Our results for family 1 showed that the device with zigzag edges (PHAGBNZZ) undergoes the metal-semiconductor transition operating in two voltage windows with a signature of a Field-Effect Transistor (FET) field-effect transistor (FET). In the armchair device (PHAGBNARM) the semiconductor-metal transition occurs, operating as switching for low voltages and as a FET for voltages from 0.2 V. On the other hand, Inelastic Electronic Tunneling Spectroscopy (IETS) inelastic electronic tunneling spectroscopy (IETS) revealedthat the devices of family 1 suffer little influence of inelastic channels on transport, with tunneling being mostly elastic. For family 2, the smaller device (PHAGNZZ1) shows a metallic behavior, undergoing the metal-semiconductor transition with increased voltage, operating as a FET device. The widest device (PHAGNZZ2) presents the behavior of a topological insulator (TI), operating in two voltage windows, such as FET for low voltages, showing TI-semiconductor transition, and resonant tunnel diode (RTD) for voltages between 0.2, and 0.45 V, evidenced by the Negative Differential Resistance (NDR). Analyzing the entire voltage window, the PHAGNZZ2 device’s I-V curve shows a signature like that of a current limiting device that we call the Molecular Positive Electronic Transition (MPET).

  • ISABELA PAMPLONA TRINDADE
  • GENERATING REALISTIC MASSIVE MIMO CHANNELS USING RAY-TRACING: IMPROVEMENTS ON THE RAYMOBTIME METHODOLOGY

  • Data: 08/09/2021
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  • Multiple-input and multiple-output (MIMO) techniques using millimeter wave (mmWave) prop-agation are essential to achieve the bit rates expected for 5G and 6G systems. This technology evolution relies on good knowledge about the propagation channels. Ray-tracing emerges as a good option among the deterministic channel modeling approaches, avoiding the high cost of performing measurement campaigns with channel sounding at such high frequencies. This dissertation presents improvements on the simulation methodology called Raymobtime, which combines two different software: a vehicle traffic simulation (SUMO) and a ray-tracing simu-lation (Remcom’s Wireless InSite), in order to generate realistic channels that guarantees some MIMO channel requirements as the spacial-time consistency, when there are smooth channel variations between closely separated users, or when they move. The improvements in the Ray-mobtime methodology developed in this dissertation include a channel characterization of cre-ated datasets, using parameters as angle and delay spread. Moreover, the work analyses a strategy to speed up simulations: using a generic setup with omnidirectional antennas in the simulation, with a post-processing stage applying the geometric model channel. The presented results show the impact of this approach in metrics such as channel capacity and channel estimation using deep learning.

  • PEDRO BEMERGUY
  • ANALYSIS OF FREQUENCY AND TIME SYNCHRONIZATION REQUIREMENTS FOR INTEGRATED ACCESS BACHKHAUL

  • Data: 03/09/2021
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  • Backhaul networks have evolved substantially throughout telecommunications history. With the industry interest in deploying dense telecommunications infrastructures, a wireless backhaul becomes a viable solution to reduce the implementation costs. In particular, on 5G NR the IAB architecture was designed to be a key enabler to turn dense networks deployments into a cost-effective option. In those scenarios, OTA synchronization is essential to establish a shared knowledge of timing and frequency, which has not been adequately addressed to the best of our knowledge until today. This works thoroughly analyzes the challenges regarding timing and frequency synchronization in this context, with a particular focus on pilot-aided synchronization. The fundamental problem of OTA synchronization is the symbol timing recovery and the CFO estimation, which will base the FO correction. As a result, this work explores different strategies using a PI loop to improve the estimation from the timing and CFO. In the end, this dissertation analyzes the performance from this synchronization procedure with the proposed synchronization requirements by the 3GPP for MIMO, CA and TDD.

  • IGOR RAMON SINIMBU MIRANDA
  • Microstrip Antennas Design for 5G.

  • Data: 03/09/2021
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  • In this work we study different microstrip antennas for the 3.5 GHz band of 5G. The first difference between the antennas is the use of silica (εr=4.4) as a substrate for antennas 1 to 3 and bismuth niobate doped with vanadium pentoxide ( εr  =47.8) for the antennas 4 to 6. The use of bismuth Niobate caused the miniaturization of antennas, as foreseen in the literature, being a desirable characteristic for 5G. In addition, periodic structures on the antenna substrate were modeled in antennas 2 and 5, using the plane wave expansion method (PWE), in order to improve their radiation characteristics. Similarly, we use Mushroom-like type periodic structures in antennas 3 and 6, in order to improve some results of the antenna parameters such as gain. All antennas were modeled in GNU Octave software and simulated in Ansys HFSS and CST Studio 2019 software. The best results for silica antennas were antenna 3 with 7.7 dB gain, 0.11 GHz bandwidth and -25 dB of reflection coefficient. Among Bismuth Niobate antennas, the one that obtained the best results for this application was antenna 6 with 3.6 dB of gain, 0.08 GHz of bandwidth and -20 dB of reflection coefficient.

  • FRANCISCO DIEGO MARTINS NOBRE
  • POWER DIVIDER FOR THREE (1X3) NON-RECIPROCAL TERAHERTZ RANGE

  • Data: 31/08/2021
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  • The present work investigated two new types of non-reciprocal power dividers, based on graphene, which operate in the THz region. The developed component divides the power of the input signal between three output ports and, in addition, has an insulating property, that is, a signal source connected to the input port is protected against possible unwanted reflections from the output ports. The device consists of a disk-shaped graphene resonator and six waveguides connected to it. These elements are deposited on a silicon dioxide (SiO 2 ), silicon (Si) and polysilicon (Si-poly) dielectric substrate, the graphene resonator being subjected to an external DC magnetic field equal to B 0 = 0.29 T for both dividers. The principle of operation of the device is the dipole resonance of the magnetized resonator. The level of division of the input power between the three output ports is around -6 dB and the isolation of the source in relation to the output ports is better than -15 dB in a band with a width equal to 3.4 % for divisor (T σ1 ) and (T σ2 ) with the central operating frequency of the divisors is 7.45 THz. The COMSOL Multiphysics software was used to numerically calculate the results.

  • YURI HERNAN SANTOS BARBOSA
  • SPREADING FACTOR OPTIMIZATION STRATEGY FOR LORA TECHNOLOGY IN A MOBILITYSTATE: AN APPROACH BASED ON FUZZY SYSTEMS

  • Data: 31/08/2021
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  • The technological advances introduced by drastically changing the way we interact with the “things” present in the world around us, where IoT networks comply with an important role with the revolutions. In view of communication as a central point that allows all "things" to be part of this connected world, together to form a network of "Internet of Things". Wireless communication provides the benefits of mobility, making it easy to add more devices to the network and making it easy to provide any object the ability to connect to the internet. Currently, there are several wireless communication technologies developed for different needs, ranging from short range to medium and long range, through the LoRaWAN protocol, has become the focus of several and research worldwide. The LoRa network server has the ability to manage the transmission definition of each node individually to maximize battery life and network resources, through the Adaptive Data Rate, however the system needs some favorable channel conditions and measures to execute the Data Rate configuration inherent to the methodology, carried out after the confirmation of the 20 successful uplinks, that is, this configuration cannot be used in situations, where endnodes and / or gateaways are in a mobility situation. Therefore, this work is based on field studies, at the frequency of 915MHz, and aims to implement and test a fuzzy logic control, which performs a Data Rate configuration in LoRa technology in a mobile situation, in intelligent ways through taking decision and in order to optimize several aspects such as the coverage area, power supply, channel conditions, time in the air between others.

  • GEAM WILLIAM PFEIFF
  • Fraud detection methods in smart grids using machine learning techniques

  • Data: 31/08/2021
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  • Non-technical losses, in most cases caused by fraud, are the main causes of financial losses for electric energy concessionaires. These losses drastically reduce the quality of electrical networks, increasing the risk of blackout, short circuits and equipment breakdowns. Thus, the development of methods that can detect non-technical losses becomes strategic. This dissertation presents two methods developed and validated for the detection of non-technical losses in smart grids. The first method consists of an Electrical Fraud Detector Based on Machine Learning, called DFEBAM, which classifies users' samples as honest or fraudulent. DFEBAM employs different machine learning algorithms that learn patterns from the users' electrical consumption data, then the method selects the algorithm that obtained the best performance and adds new stochastic features generated from the original data. By adding new features, the final model was validated and obtained a detection rate equal to 98.02% and a false positive rate equal to 2.47%. The second method consists of a Data-oriented Ensemble Predictor based on Time Series Classiers for Fraud Detection, called DETECT. The ensemble predictor is created from five time series classifiers, which uses the user's electrical consumption data to learn patterns and later classify the new samples into honest or one of six specific fraud cases. DETECT is totally focused on handling time series data, which differentiates it from most non-technical loss detectors in the literature. In addition to using individual time series classifiers to be compared with DETECT, conventional classifiers were also used, in the end DETECT had a false positive rate equal to 1.61%, which is considered extremely low, as well as an improvement up to 24% in terms of detection rate when compared to other classifiers.

  • DALILA REIS GRIPPA
  • Graphene-based directional couplers in the terahertz frequency range

  • Data: 30/08/2021
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  • Two new types of graphene-based devices operating in the Terahertz (THz) region are suggested and analyzed in this work, being two four-port directional couplers. The first coupler has graphene waveguides tilted sideways at a 60° angle. The second directional coupler already has waveguides forming an angle of 90° between them, thus being called a directional coupler with parallel-orthogonal waveguides. The cross-section of the components has a four-layer structure, composed of graphene, silica (SiO2), silicon (Si) and a thin layer of polysilicon. The operating principle of the devices consists of the propagation of surface polariton plasmon waves (SPP's) in graphene waveguides. To carry out the analysis of the scattering matrices of the devices, we used Group Theory. For the numerical calculations we used the COMSOL Multiphysics software, such that variations of physical and geometric parameters were made to analyze how they influence the device's operation. The directional coupler with 60° laterally inclined waveguides had a signal split of -3.8 dB at the center frequency of 3.75 THz with isolation and reflection better than -20 dB at a bandwidth of 14%. The directional coupler with parallel - orthogonal waveguides presented a signal division of -4 dB at the center frequency of 4.4 THz with isolation and reflection around -17 dB and -20 dB, respectively. Device frequency bands can be dynamically controlled by changing the voltage applied between the graphene layer and the polysilicon layer.

  • LELIS ARAUJO DE OLIVEIRA
  • PERFORMANCE ANALYSIS OF A FULLY OPTICAL NETWORK USING AWG AND FBG DEMULTIPLEXERS AND APPLICATIONS IN OPTICAL SENSORS.

  • Data: 27/08/2021
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  • We present in this work, a study of numerical simulations of the performance of Array Wave Guide (AWG) and Fiber Bragg Grating (FBG) fiber demultiplexers in a photonic crystal fiber all-optical network ( PCF) considering dispersive and nonlinear effects, and applications in FBG sensors. The simulations use a set of differential equations that define the pulse dynamics in a wavelength division multiplexing (WDM) network configuration in PCF and in SMF optical fiber. For the simulation and analysis steps we use the commercial software OptiGrating, used to model devices that incorporate diffraction gratings in optical fibers, and the OptiSystem, to simulate the propagation of the signals in the fibers. The performance analysis of the demultiplexers was performed by comparing the data obtained in terms of bit error rate (BER), quality factor (Q factor) and gain, in a dense WDM system with 50 GHz channel spacing , and transmission rate of 12 Gbit/s. The results and characterization showed that the FBG demultiplexer in terms of BER and Q factor for the PCF fiber had better performance when compared to the SMF fiber and the AWG demultiplexer was well balanced in both fibers. For the sensor configurations in this thesis, we use FBGs and we propose two sensors, the first of deformation, which has its functionality applied to measuring the radial diameter growth of the stem of Amazonian trees, and the feasibility of using this type of configuration for the monitoring of forest areas, forestry, climate change and irrigation is very promising. The simulation results indicate that it is possible to detect minute variations in diameters with a resolution in the range of 0.5 m (0.0005 mm). And the second liquid level, applied to simultaneously measure the level and temperature of the waters of rivers in the Amazon, where this has enormous potential to be used in monitoring the water level of rivers in areas that suffer from flood risks . The results indicate an excellent sensitivity of 8.6 pm/cm and water level measurements up to the limit of 4.0 m.

  • ANA CAROLINA NEVES PARDAUIL PIRES
  • ABORDAGEM COMBINADA USANDO FLORESTA ALEATÓRIA DE CLUSTERIZAÇÃO PARA AVALIAR PADRÕES DE DESCARGA PARCIAL EM HIDROGERADORES

  • Data: 26/08/2021
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  • ABORDAGEM COMBINADA USANDO FLORESTA ALEATÓRIA DE CLUSTERIZAÇÃO PARA AVALIAR PADRÕES DE DESCARGA PARCIAL EM HIDROGERADORES

  • THALITA AYASS DE SOUZA
  • FUZZY SYSTEM FOR HANDOVER DECISION MAKING IN FLYING AD HOC NETWORKS.

  • Data: 13/08/2021
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  • Within the scope of new technologies for wireless communications, FANETs (Flying Ad Hoc Networks) have emerged as an alternative to provide and/or expand network coverage in the most diverse types of applications due its relative ease of implementation, high mobility and low maintenance cost. However, this type of network has particularities in its components that need to be considered in order to guarantee the Quality of Service (QoS) and provide continuous access to the user even in circumstances of great mobility. In this context, this work proposes a Fuzzy system for making a handover decision that uses three parameters as input: 1) user speed; 2) signal strength; 3) battery level. Based on the output indicated by the Fuzzy system, a performance evaluation between the traditional handover and the one proposed in this work is carried out for a video transmission scenario between the air stations and the mobile user and through the QoS and Quality of Experience metrics (QoE) established, analyzed the quality of communication. The results obtained showed that the decision-making factors of the proposed model met the good maintenance of service continuity without compromising the quality of the application, as opposed to the traditional model that caused severe degradations in the received media.

     

  • CARLOS EDUARDO DURANS NOGUEIRA
  • STOCHASTIC AUGMENTATION OF BIOINSPIRED CONTROLLERS APLLIED TO QUADCOPTERS UAVS

  • Data: 13/08/2021
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  • This work describes a sequence of procedures for the implementation of digital controllers applied to the Parrot® AR Drone 2.0 in order to obtain two controllers that will be evaluated: a Bioinspired Controller and a controller designed through Stochastic Augmentation by Generalized Minimum Variance Control (SAGMVC). The Bioinspired Controller is acquired by means of identification via Artificial Neural Networks (ANNs) of the human control profile, which is performed by manual commands via joystick. In turn, the SAGMVC controller is designed using the synaptic weights obtained by ANNs of a bioinspired controller, which can be compared to the polynomial parameters of an RST controller. Thus, it is intended to observe the performance of controllers based on the human capacity to control systems, analyzing, at the same time, how much such systems can be improved. The main objectives pursued by the study are: the consolidation of the Stochastic Augmentation procedure as a method for improving linear controllers; in the improvement of controllers via Artificial Neural Networks; in the dissemination of optimal controllers, focusing on robustness and minimizing the energy that will be wasted; and in the design of controllers for Unmanned Aerial Vehicles. To assess the fulfillment of these objectives, the response of the controlled system, the control signal, the performance indices (ISE, ISU, TVC, IAE) and the gain and phase margins, using simulated and experimental indoor tests, were generated. From the results obtained — dividing the drone control into four dynamics: pitch, yaw, roll and altitude — it is evident that the main objectives were fulfilled, that is, the projected controllers showed improvements in performance indices, in the transient response profile and in the energy expenditure of the system. Furthermore, it was validated the hypothesis that it is possible to design an ANN Bioinspired controller whose synaptic weights are similar to parameters of RST controllers, and it was also inferred that SAGMVC showed significant improvements in system performance, compared to both simple manual control via joystick and Bioinspired control.

  • JONAS MARINHO DUARTE
  • ELETRONIC TRANSPORT IN THE PRESENCE OF MAJORANA FERMIONS IN A ZIGZAG CHAIN OF ATOMS OVER A TOPOLOGICAL SUPERCONDUCTOR

  • Data: 12/08/2021
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  • Research in solid state physics with experimental nanodevices with hybrid semiconductor and superconductor structure has highlighted the realization of topological superconductor for detection of Majorana Fermions (MF). In this work, we will calculate transport properties such as electric current and differential conductance, where we look for Majorana zero-mode signatures. We can characterize such a signature by a conduction resonance, that is, a conductance peak in a region of zero polarization. We studied the electronic transport in a nanodevice composed of a quantum dot (QD), with only one energy level, coupled to two electrodes (Leads). The electrodes are connected to the quantum dot through ΓR and ΓL couplings. We couple to the quantum dot a zigzag chain of atoms containing 8 sites. The chain in question is on a topological superconducting substrate with p-wave pairing. C2i-1 and C2i are Majorana operators on each site. CA,1 and CB,1 are Majorana modes at the ends of the zigzag chain. For the internal couplings of the zigzag chain, we have the parameters h α and Δα, called hopping and Cooper parameter, respectively. We use the non-equilibrium Green functions, that is, the Keldysh formalism. Through these formalisms we deduce the Meir-Wingreen electric current formula and finally the electric current formula similar to the Landauer-Büttiker formula for the studied system, in equilibrium situations. Through these results, we used a matrix formalism for computational calculation, where we obtained the electric current and differential conductance graphs to characterize the design of the nanodevice. The I-V characteristic curves of the system show Majorana modes and the study of resonance in conductance has a behavior analogous to electric current in a field effect transistor.

  • JORGE AMARO DE SARGES CARDOSO
  • HETEROGENEOUS WIRELESS NETWORKS WITH MOBILE DEVICES OF MULTIPLE INTERFACES FOR SIMULTANEOUS CONNECTIONS USING FUZZY SYSTEM

  • Data: 12/08/2021
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  • With the exponential increase in heterogeneous wireless networks today, there has been a growing interest from the academic community for issues related to handover problems. The main objective of this paper is to evaluate the quality of service and performance of a device with a dual interface that connects simultaneously to two heterogeneous networks with no competition in the exchange of packets between them. It is a proposal to solve the mitigation of handover impacts. The tool used for evaluation was the Network Simulator 2. The results showed a better use of the band in comparison to the scenario using a traditional mobile device.

  • ANDREIA VANESSA RODRIGUES LOPES
  • ANÁLISE ESTATÍSTICA E MODELAGEM EMPÍRICA PARA CAMPUS DENSAMENTE ARBORIZADO UTILIZANDO A TECNOLOGIA LORA EM 915 MHZ

  • Data: 23/07/2021
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  • ANÁLISE ESTATÍSTICA E MODELAGEM EMPÍRICA PARA CAMPUS DENSAMENTE ARBORIZADO UTILIZANDO A TECNOLOGIA LORA EM 915 MHZ

  • RAPHAEL PABLO DE SOUZA BARRADAS
  • METODOLOGIA PARA ANÁLISE DE CRITICIDADE DE REDES DE DISTRIBUIÇÃO SUBMETIDAS A DESCARGAS ATMOSFÉRICAS DIRETAS

  • Data: 14/07/2021
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  • Descargas atmosféricas diretas em redes aéreas de distribuição causam, inevitavelmente, sérios danos ao isolamento, levando frequentemente ao desligamento parcial ou total do sistema elétrico. A instalação de para-raios pode ser muito eficaz e é comumente usada para minimizar esse problema; no entanto, considerando que as redes de distribuição de energia geralmente apresentam um número muito grande de nós elétricos, o uso maciço de para-raios pode não ser economicamente viável. Dessa maneira, esta tese propõe uma metodologia para alocar pára-raios que podem reduzir significativamente o número de pára-raios a serem instalados, mas ao mesmo tempo mantendo um nível de proteção adequado para a rede de distribuição. A metodologia proposta, denominada Cruzamento de Descargas Diretas (CDD), analisa a criticidade da rede com base em dois fatores principais, que são as magnitudes das sobretensões e o número de flashovers provocados por descargas atmosféricas, e define uma função de desempenho usada para indicar o local recomendado para a instalação dos para-raios. Os estudos de simulação foram realizados usando duas redes de distribuição teste e o software ATP para demonstrar a eficácia da solução proposta, o que é confirmado pelos resultados apresentados.

  • IAGO RANIERI MIRANDA RODRIGUES MORAIS
  • AVALIAÇÃO DO IMPACTO DAS TENSÕES HARMÔNICAS NA TEMPERATURA DA CARCAÇA DE MOTORES ELÉTRICOS LIGADOS EM ESTRELA ATERRADA POR MEIO DE ANÁLISE DE REGRESSÃO E TERMOGRAFIA

  • Data: 13/07/2021
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  • Os motores elétricos são equipamentos elétricos largamente utilizados em diversos processos industriais, sendo responsáveis por uma parcela significativa do consumo de energia dessas indústrias. Ao longo dos últimos anos, os motores elétricos têm sofrido diversas melhorias em suas estruturas devido a sua grande importância em diversos setores da sociedade aliada com as pressões por ações mais sustentáveis e eficientes, o que os levou a atingir rendimentos em torno de 96%. No entanto, a presença de certos distúrbios que degradam a qualidade da energia elétrica pode afetar nocivamente o funcionamento desse tipo de máquina, e , consequentemente, a sua eficiência. Com base nesse contexto, esse trabalho buscou avaliar como as tensões harmônicas de baixa frequência (especificamente 2º, 3º e 5º harmônicos de tensão) impactam no aumento de temperatura da carcaça de motores elétricos classe IE2, IE3 e IE4 quando ligado em estrela aterrado utilizando termografia. Esse trabalho mostrou que as tensões harmônicas podem provocar um aumento significativo da temperatura da carcaça dos motores, onde destaca-se o 2º harmônico.
  • SIDNIR CARLOS BAIA FERREIRA
  • LORA GATEWAY OPTIMAL PLACEMENT METHODOLOGY IN A SMART CAMPUS
    SCENARIO USING EPSO METAHEURISTIC

  • Data: 06/07/2021
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  • The Internet of Things (IoT) paradigm connect objects by software, sensors, and several other applications to exchange information with other devices, people, and wireless systems. A Smart Campus scenario uses IoT to enable technologies that improve service performance and well-being for university campus users. A wireless communication network capable of connecting and transmitting information from devices and sensors with IoT application servers is necessary to make this scenario feasible. Low Power Wide Area Networks (LPWAN) have proven to be efficient for connecting intelligent devices. LoRa (Long Range) technology is a type of LPWAN operating in the unlicensed frequency range of 915 MHz, whose communication occurs through gateways that act as exchange points between the sensors and the central server. Optimizing the placement of these gateways and the quantity needed is essential for planning IoT networks and ensuring the quality of coverage. We propose a methodology that uses the Evolutionary Particle Swarm Optimization (EPSO), a meta-heuristic based on evolutionary and swarm intelligence, to determine the LoRa optimal gateway placement for Federal University of Pará – Campus Guamá (UFPA) Smart Campus. The UFPA propagation model, adjusted for the scenario, predicts the received signal strength and is used as an input parameter by EPSO. Four thresholds of signal reception sensitivity generated the optimal placement solutions, and we performed the solutions evaluations through the Pareto front. The stability of the meta-heuristic in finding solutions was confirmed using the Monte Carlo method. The results showed threshold sensitivity strong influence in gateways quantity and coverage area, resulting in a relevant parameter for the planning IoT-LoRa networks, which also implies in a propagation model consistent choice for the deployment scenario. The threshold sensitivity -104 dBm was more suitable for UFPA Smart Campus because forests separate the campuses, and EPSO selected centralized points with sufficient coverage radius for each campus. Based on these results, the optimal placement methodology can assist in the planning and implementation IoT-LoRa networks, reducing possible errors and, consequently, costs in a Smart Campus network design.

  • ELAINE CRISTINA SANTOS DA SILVA
  • NOVO MÉTODO ADAPTATIVO DE PROJEÇÃO DE ENERGIA INJETADA NO SISTEMA ELÉTRICO DE DISTRIBUIÇÃO, EM PERÍODO DE PANDEMIA DO COVID-19, UTILIZANDO REDES NEURAIS ARTIFICIAIS

  • Data: 05/07/2021
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  • Este trabalho tem por objetivo apresentar os resultados projetados de energia injetada no sistema de distribuição da concessionária Equatorial Pará e Maranhão, utilizando uma nova metodologia e com apoio das redes neurais artificiais para fazer predição de Energia Injetada em tempos de pandemia, que impactou diretamente os perfis de consumo. O principal desafio é tornar as previsões de energia mais aderentes a realidade, e com menores taxas de erro para tornar os resultados mais confiáveis na utilização do planejamento da empresa, pois o modelo proposto irá respaldar à área estratégica com uma opção viável de metodologia a ser utilizada, para direcionar as tomadas de decisões.

  • FLAVIANE LOUZEIRO DA SILVA
  • Methodology for obtaining the Break Points of the Large Scale Multi-Slope Model Using Genetic Algorithm.
  • Data: 02/07/2021
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  • The research and development of wireless communication systems are accompanied by the characterization of the channel on which the signal will be transmitted. In outdoor environments there are several factors that influence the propagation of the signal, such as large buildings, the characteristics of the environment: relief, topography and vegetation, among others, causing losses due to diffraction, reflection and scattering. In the design of wireless communication systems, knowledge of the characteristics of radio propagation in the propagation environment is essential. Thus, in the literature there are several works aimed at the analysis and construction of propagation models. These models assist in the design of wireless network coverage, making it a useful tool in the design of link systems. Numerous propagation prediction methods are available, among them there is the double slope model, known in the literature as Dual Slope and the model with multiple slopes, known in the literature as Multi-Slope. One of the challenges of these models is to obtain the segmentation distance of the route, in addition to the number of segmentation points for the model with multiple segments. Several methodologies have been proposed to solve these challenges and, in this work, a methodology will be presented to optimize this search with the aid of a genetic algorithm. The genetic algorithm is one of the main research topics in Evolutionary Computing, which in turn is a branch of Computational Intelligence research, proposing a new approach to solving problems inspired by natural selection. These algorithms simulate natural population survival and reproduction processes, comprised of a set of search and optimization techniques inspired by the natural evolution of the species. In this algorithm, the favorable characteristics configure patterns that are strengthened in the successors. In turn, unsuitable traits are rarely passed on to descendants so that they can disappear from the population. The objective function of the genetic algorithm assesses how efficient the segmentation distance proposed by the individual in the population is. In view of the results obtained, it is possible to conclude that the individual who has the best accuracy allows the decay coefficients most adjusted to the segments to be obtained. Thus, the methodology proved to be efficient for obtaining the reference distance in noisy channel modeling.

  • PEDRO BARBOSA DE SOUSA FILHO
  • DETECTION OF POTENTIAL FOCUSES OF REPRODUCTION OF MOSQUITOES OF THE GENDER AEDES: CASE STUDY IN THE CITY OF CANAÃ DOS CARAJAS - PA.

  • Data: 30/06/2021
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  • This work is the problem of detecting potential breeding spots for Aedes mosquitoes in urban areas, using computer vision and machine learning techniques, in a case study of the city of Canaã dos Carajás, in the state of Pará. In this context, it is proposed to use a set of aerial images, acquired by drone, which have different objects in various scenarios: different, altitudes and dispositions of the labeled objects. The images were manually annotated, and the objects separated into two major classes, Water, and garbage, to compose the training data set for the development of an automatic object detector based on the Yolov4 architecture. The results obtained in tests performed with images of urban areas in the city of Canaã dos Carajás, are possible satisfactory and indicators that the model presented works as an efficient solution to assist in the identification and detection of potential breeding grounds for mosquitoes in aerial images.

  • MARCELA ALVES DE SOUZA
  • UM FRAMEWORK PARA PLANEJAMENTO DE REDES EM ÁREAS RURAIS E REMOTAS CONSIDERANDO FATORES TÉCNICOS, ECONÔMICOS E SOCIAIS

  • Data: 30/06/2021
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  • A expansão dos serviços de banda larga e das aplicações de TIC representa um desafio significativo para as operadoras de banda larga, especialmente quando se considera os requisitos relacionados ao custo total de propriedade dessas tecnologias. Nos últimos anos, o processo de expansão avançou significativamente nos últimos anos, mas ainda representa um desafio a ser superado, dada a necessidade de prestar serviços de baixo custo às populações de áreas rurais e remotas. Questões relacionadas à geografia do local, baixa renda dos residentes e falta de infraestrutura pública levam a uma relação desvantajosa entre as receitas potenciais para as operadoras e os custos mais altos de implantação da infraestrutura de rede. Embora a literatura relacionada indique diversos esforços de pesquisa direcionados ao fornecimento de conectividade, faltam abordagens que considerem características específicas de tais regiões ou tenham serviços e aplicativos de rede adaptados às necessidades dessas comunidades. Assim, este trabalho propõe um framework técnico e econômico para a implantação de redes banda larga em áreas rurais e remotas, realizando o dimensionamento do custo total de propriedade da rede, considerando despesas de capital e operacionais da rede. O escopo da proposta também contempla a aplicação de técnicas de análise de viabilidade econômica para auxiliar a tomada de decisão por meio da compreensão do impacto dos investimentos financeiros realizados e dos lucros esperados pelas operadoras de banda larga. Além disso, propomos a utilização de indicadores socioeconômicos para projetar o potencial impacto social no desenvolvimento dessas regiões. Elaboramos um estudo de caso para demonstrar o funcionamento do framework proposto e seus principais componentes. Considerando dados reais de um município amazônico, mostramos, ao reduzir os custos de implantação, que é possível reduzir o custo de assinatura de serviços de banda larga para usuários finais, contribuindo assim para o processo de democratização do acesso aos serviços digitais.

  • DANIEL DA CONCEICAO PINHEIRO
  • INIBIDOR ROBUSTO DE EVENTOS DE RUNAWAY NO COMUTADOR DE TAPE DE REGULADORES DE TENSÃO SOB CENÁRIOS DE FLUXO INVERSO EM REDES DE DISTRIBUIÇÃO ATIVAS E RECONFIGURÁVEIS

  • Data: 02/06/2021
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  • INIBIDOR ROBUSTO DE EVENTOS DE RUNAWAY NO COMUTADOR DE TAPE DE REGULADORES DE TENSÃO SOB CENÁRIOS DE FLUXO INVERSO EM REDES DE DISTRIBUIÇÃO ATIVAS E RECONFIGURÁVEIS

  • JOÃO RODRIGO DA SILVA MUNIZ
  • “Desenvolvimento de Software para Automação da Modelagem de Redes Elétricas de Grande Porte no Alternative
    Transient Program”.

  • Data: 28/05/2021
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  • “Desenvolvimento de Software para Automação da Modelagem de Redes Elétricas de Grande Porte no Alternative
    Transient Program”.

  • ANDRÉ AUGUSTO PACHECO DE CARVALHO
  •  

     

  • Data: 21/05/2021
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  • Atualmente, o 4G/LTE já é utilizado em 205 países por 661 diferentes operadoras, cobrindo 78% da população de acordo com a GSMA, assim pesquisas e estudos acerca da caracterização de canal para esta tecnologia são de extrema importância. Afim de explorar ambientes com características amazônicas, uma vez que modelos clássicos não contemplam valores que melhor caracterizem esse ambiente, foram realizadas campanhas de medições na cidade de Belém no Pará para modelagem de canal em larga escala em 1.8 e 2.6 GHz. E este trabalho, apresenta um novo método para encontrar parâmetros ótimos para os modelos SUI, ECC-33,UFPA e FI, por meio dos algoritmos de otimização meta-heurísticas: Algoritmo Genético (GA), Algoritmo do Morcego (BAT), Algoritmo de Polinização por Flores (FPA) e Cuckoo Search (CS) para uma modelagem robusta e mais precisa. Os modelos ajustados com os valores otimizados apresentaram melhores resultados quando comparados a modelagem sem otimização, validados pelas métricas de desempenho RMSE e Desvio padrão diminuindo em até 93%. Para a métrica de GRG-MAPE demonstrando uma acurácia nos resultados dos modelos otimizados. Mostrando que o uso de Algoritmos Meta-heurísticos Bioinspirados é uma boa opção para a modelagem de canal.

  • CAMILA SOUZA ALVES
  • ANÁLISE DE DESEMPENHO DE ESTRATÉGIAS CONVENCIONAIS E EMERGENTES PARA CONTROLE DE TENSÃO EM REDES DE DISTRIBUIÇÃO DE BAIXA TENSÃO COM PRESENÇA DE MICROGERAÇÃO FOTOVOLTAICA

  • Data: 18/05/2021
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  • ANÁLISE DE DESEMPENHO DE ESTRATÉGIAS CONVENCIONAIS E EMERGENTES PARA CONTROLE DE TENSÃO EM REDES DE DISTRIBUIÇÃO DE BAIXA TENSÃO COM PRESENÇA DE MICROGERAÇÃO FOTOVOLTAICA

  • CARLOS EDUARDO MOREIRA RODRIGUES
  • PROPOSTA DE METODOLOGIA DE CÁLCULO DE PERDAS TÉCNICAS EM REDES DE DISTRIBUIÇÃO DE ENERGIA ELÉTRICA VIA REDES EQUIVALENTES DE ORDEM MINIMA

  • Data: 14/05/2021
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  •    As perdas de energia elétrica se constituem em uma questão fundamental no setor de distribuição, sendo uma consequência inevitável do transporte de energia dos pontos de suprimento até às unidades consumidoras e constituindo-se um dos fatores a serem considerados nas etapas de planejamento e operação da rede. Elas devem ser continuamente monitoradas para que sejam mantidas dentro de níveis aceitáveis a fim de assegurar a rentabilidade das concessionárias e a modicidade tarifária. Dada a importância da estimativa das perdas técnicas e não técnicas no sistema, ao longo dos anos diversas metodologias foram propostas para a aferição precisa dessas parcelas. Nesse contexto, no ano de 2018, foi apresentada uma nova proposta para o cálculo de perdas técnicas e não técnicas em redes de distribuição, a Impedância Equivalente Operacional (IEO), possibilitando a obtenção das parcelas de perdas com boa precisão e baixo custo computacional, sob diferentes condições operativas da rede. Tomando como base a proposta da Impedância Equivalente Operacional para o cálculo de perdas nos sistemas de distribuição, este trabalho apresenta uma metodologia de aplicação da mesma para um alimentador real de distribuição, tomando como ponto de partida a modelagem da rede no Open Distribution System Simulator (OpenDSS), considerando dados de medição de faturamento das unidades consumidoras, energia injetada nos alimentadores e na subestação, fator de potência medido nos alimentadores, campanhas de medição para caracterização do consumo das cargas para dias úteis, sábados e domingos e perdas dos medidores de energia conectados às unidades consumidoras. De posse de todos esses dados, é possível o cálculo das perdas técnicas devido ao atendimento às cargas regulares, das perdas não técnicas e das perdas técnicas devido ao atendimento às perdas não técnicas para os dias úteis, sábados e domingos e a posterior integralização dos dados para a obtenção dos resultados de perdas mensais em termos de energia.

  • HUGO PEREIRA KURIBAYASHI
  • FRAMEWORK PARA ORQUESTRAÇÃO CONJUNTA DE MECANISMOS DE ASSOCIAÇÃO DE USUÁRIOS E ALOCAÇÃO DE RECURSOS EM REDES MÓVEIS DE PRÓXIMA GERAÇÃO

  • Data: 14/05/2021
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  • A demanda de tráfego em sistemas de comunicação sem fio tem se tornado uma questão importante nas últimas décadas. Projeta-se uma tendência cada vez maior para os próximos anos, com a expectativa de que o tráfego de dados explosivo se materialize e os usuários móveis imponham novos requisitos de qualidade de serviço. Essa crescente demanda de tráfego, combinada com cenários de rede heterogênea cada vez mais complexos e densos (HetNet), apresenta cada vez mais desafios para as operadoras de rede móvel em termos de serviço, cobertura, balanceamento de carga e qualidade de serviço. Considerando o mecanismo de associação tradicional com base na potência máxima recebida, as HetNets tendem a permanecer desequilibradas, tornando um desafio atender aos requisitos de tráfego dos usuários móveis. Além disso, esta proposta de tese propõe uma abordagem baseada em aprendizado de máquina para orquestrar conjuntamente a associação de usuários e mecanismos de balanceamento de carga em HetNets. A abordagem proposta consiste em um otimizador de duas fases, onde ao invés de tentar maximizar a taxa de downlink alcançável por usuário, indicadores chave de desempenho como a satisfação da UE e perfis de QoS prioritários são considerados. A primeira fase acopla algoritmos de inteligência de enxame com métodos de agrupamento dinâmico para detectar e agrupar usuários com condições de canal ruins. Além disso, a segunda fase explora a adoção de técnicas de aprendizagem por reforço profundo para ajustar o processo de associação de usuários, para fornecer melhores condições de tráfego aos UEs. Esta fase considera as cargas das estações base e a relação sinal-interferência-mais-ruído (SINR) do equipamento do usuário, para influenciar de forma distribuída o comportamento da rede e otimizar o equilíbrio da rede. Ao considerar o uso de ferramentas de simulação, essa abordagem orientada a objetivos pode representar uma solução promissora para fornecer melhores níveis de satisfação do usuário a longo prazo.

  • RENATO LUZ CAVALCANTE
  • IMPACTO DA INSERÇÃO DE GERAÇÃO FOTOVOLTAICA EM SISTEMAS ISOLADOS ATENDIDOS POR TERMOELÉTRICAS A DIESEL

  • Data: 12/05/2021
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  • IMPACTO DA INSERÇÃO DE GERAÇÃO FOTOVOLTAICA EM SISTEMAS ISOLADOS ATENDIDOS POR TERMOELÉTRICAS A DIESEL

  • JOSÉ DE ARIMATÉIA ALVES VIEIRA FILHO
  • DESENVOLVIMENTO DE UMA BATEDEIRA DE AÇAÍ EM CORRENTE CONTÍNUA E MONITORAMENTO DE SUA APLICAÇÃO EM UMA EDIFICAÇÃO RIBEIRINHA NA AMAZÔNIA SUPRIDA POR SISTEMA FOTOVOLTAICO ISOLADO

  • Data: 28/04/2021
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  • DESENVOLVIMENTO DE UMA BATEDEIRA DE AÇAÍ EM CORRENTE CONTÍNUA E MONITORAMENTO DE SUA APLICAÇÃO EM UMA EDIFICAÇÃO RIBEIRINHA NA AMAZÔNIA SUPRIDA POR SISTEMA FOTOVOLTAICO ISOLADO

  • SERGIO AUGUSTO LOBO GLUCK PAUL
  • Automatic Detection of Azimuth Change in Antennas for 5G-IoT Networks Using Deep Learning

  • Data: 23/04/2021
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  • This work is about applied artificial intelligence techniques solving a telecommunications problem. 5G-IoT antennas will operate at high frequencies. Therefore, they individual coverage area will be smaller. Targeting the antenna correctly ensures adequate network coverage, but the antennas azimuths undergo many involuntary changes. The only way to audit azimuths on a mobile network is through manual measurements on each antenna, a time-consuming and unreliable task. The objective of this research is to present a digital solution for automatic measurement and detection of azimuth change in 5GIoT antennas. Using techniques of Deep Learning and Internet of Things, the proposed work inserts computer vision in the smart antennas concept. Satisfactory results in simulated tests are presented and prove that the model presented works as an efficient solution for azimuth auditing, collaborating with mobile networks coverage quality.

  • EDNEY ALMEIDA DO NASCIMENTO
  • ANALYSIS OF THE TIDAL EFFECT ON THE PROVISION OF RESOURCES IN HETEROGENEOUS RADIO ACCESS NETWORKS

  • Data: 12/04/2021
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  • The planning and analysis of the fifth-generation mobile networks (5G) considering phenomena such as the tidal effect, is extremely important for the efficiency and quality of services provided to users. The tidal effect can be characterized as the space-time fluctuation of data traffic, inevitable in different types of networks, generating areas of intense resource overload in places/periods of constant migration of people and use of mobile equipment. To study the impacts of this phenomenon in the face of the high demand for data from 5G networks, this work presents an analysis in the Manhattan (New York) scenario through real data from mobile subscribers collected from social networks based on geolocation LBSN (Location-Based Social Network). Factors for access availability, resource allocation and load provisioning in the network were considered, aggregating the main components of the C-RAN (Centralized Radio Access Network) and D-RAN (Distributed Radio Access Network) in the proposed model. Considering the impact of the problems caused by the tidal effect, as well as the high traffic demand expected by the 5G, it was evident in the studied scenario the importance of improvements in planning, in the choice of network access architectures used, in the models for scaling/provisioning network, as well as dynamic resource allocation schemes at times of varying traffic density. The results showed that the scaling and provisioning of Small Cells (SCs) can be performed to meet the changing demands of the network, applying dynamic resource allocation schemes in times of low and high traffic density, enabling a reduction of up to 10% in quantitative number of SCs, increasing the throughput of the data flow by 3.3%, reducing the probability of blocking by 3.6%. The results also demonstrated that the analysis of the tidal effect was able to determine the hotspots in the scenario where the demands demanded greater coverage resources, connections in the SCs and/or Macro Cells (BS), as well as the areas with the highest rates of disconnected users.

  • CARLOS ANDRE DE MATTOS TEIXEIRA
  • MORTALITY UNDERREPORTING: AN ANALYSIS OF EXCESSIVE DEATHS DUE TO SEVERE ACUTE RESPIRATORY SYNDROME DURING THE SARS-COV-2 PANDEMIC IN BRAZIL

  • Data: 26/03/2021
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  • MHuman history has been marked by devastating outbreaks of infectious diseases, many of which have occurred over periods of political, economic and social change in society. At the end of 2019, cases of one of a new variant of the coronavirus, the SARS-CoV-2, were reported by the World Health Organization (WHO) in the Hubei province, China. In January 2021, the COVID-19 pandemic exceeded 9.2 million confirmed cases and 220,000 deaths reported in Brazil. During the initial period of the pandemic, sudden increases in the number of cases of other respiratory system diseases were also identified. Severe Acute Respiratory Syndrome (SARS), caused by the SARS-CoV, peaked at 557 reported deaths in the city of Manaus between March and May 2020, contrasting with only 8 deaths from the previous year. In this scenario, it is reasonable to state that there was a high underreporting of mortality during the COVID-19 pandemic in the country. This work aims to analyze and measure the excess deaths due to SARS that occurred during the SARS-CoV-2 pandemic in Brazil, in order to estimate the mortality underreporting occurred during the COVID-19 pandemic. Data from official Brazilian government sources were obtained to compose the time series of deaths by SRAG for the 27 capitals of Brazil. Time Series Prediction Models were used to predict the expected deaths for the year 2020. The predictions are then used to identify the anomalies that occurred during the pandemic period. Anomalies caused by excess mortality from SARS were detected starting in March 2020 for all the capitals of the country. The analyzes conducted in this work seek to contribute to the estimation of the real COVID-19 mortality scenario in Brazil, assisting government entities decision-making based on the correction of official data.

  • GABRIEL VIANNA SOARES ROCHA
  • ALOCAÇÃO ÓTIMA DE PARA-RAIOS EM REDES DE DISTRIBUIÇÃO DE ENERGIA ELÉTRICA USANDO ALGORITMOS GENÉTICOS E SIMULAÇÃO ATP

  • Data: 22/03/2021
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  • The efficient protection of electric power distribution networks against lightning discharges is a crucial problem for distribution electric utilities. To solve this problem, the great challenge is to find a solution for the installation of surge arresters at specific points in the electrical grid and in a sufficient quantity that can ensure an adequate level of equipment protection and be within the utility´s budget. As a solution to this problem using ATP (Alternative Transient Program), this paper presents a methodology for optimized surge arrester allocation based on genetic algorithm (GA), with a fitness function that maximizes the number of protected equipment according to the financial availability for investment in surge arresters. As ATP may demand too much processing time when running large distribution grids, an innovative procedure is implemented to obtain an overvoltage severity description of the grid and select only the most critical electric nodes for the incidence of lightning discharges, in the GA allocation procedure. Results obtained for the IEEE-123 bus electric feeder indicated a great reduction of flashover occurrence, thus increasing the equipment protection level.

  • EVELIN HELENA SILVA CARDOSO
  • NOVEL MULTILAYERED CELLULAR AUTOMATA FOR FLYING CELLS POSITIONING ON 5G CELLULAR SELF-ORGANISING NETWORKS

  • Data: 12/03/2021
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  • The fifth generation of cellular mobile networks (5G) will have a profound impact on the development of smart cities. Issues such as "How telecommunications operators will efficiently provide network infrastructure", "When and where service quality parameters are degraded or below expectations" should be considered. In this context, the use of base stations carried by Unmanned Aerial Vehicles (UAV) acting as flying cells to compensate the service of mobile networks in areas where telecommunications systems are challenged by abnormal conditions during their operation has attracted attention. This thesis presents an intelligent solution based on a Novel Multilayered Cellular Automata for the positioning of flying cells and the consequent improvement of the capacity of the network in temporary situations of heavy traffic, such as in congested avenues during some hours of the day, overcrowded events, disaster situations or hotspot traffic. In this new distributed approach, all base stations carried by UAVs operate in parallel. Self-organization arises from an emerging pattern based on the application of simple rules in a defined neighborhood. The proposed scheme considers backhaul and radio access network restrictions and users' requirements in terms of throughput in the downlink. From discrete simulation using MATLAB software, the results show that the proposed algorithm has a favorable performance compared to other schemes in terms of all the metrics considered. Thus, the simulated experiments show the benefits of the proposed solution for the fast and efficient positioning of several flying base stations to respond in real time to urgent changes in the network.

  • FITERLINGE MARTINS DE SOUSA
  • GRAPHENE NANORIBBONS WITH ARMICHAIR AND ZIGZAG EDGES APPLIED TO ANTENNAS WITH PBG SUBSTRATE IN THZ BAND

  • Data: 26/02/2021
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  • In this work, graphene nanowires are applied to patch antennas (the antenna patch is composed of graphene material). The radiation characteristics of these antennas are analyzed in the terahertz band. Antenna variations were designed to observe the influence of certain components in relation to the performance of the proposed antenna, such as pbg substrate, nanowire edges with armchair structure, nanowire edges with zigzag structure, pbg graphene and dielectric substrate. The first variation is the addition of graphene nanoribbons (armchair and zigzag) on the left and right edges of the graphene patch, in order to evaluate the influence of these structures on a patch antenna. Subsequently, air holes are inserted in the silica substrate in order to reduce the effect of surface waves and to increase bandwidth, the insertion of a graphene PBG substrate with dielectric material is also analyzed. Octave and HFSS software were used for the modeling and simulation of the antenna and its variations. The results obtained (loss of return, impedance, radiation diagram, gain and current density) were good when the structure was modeled only with silica substrate and the best nanoribbon contributed to the performance of the graphene patch antenna was that of the structure in zigzag. However, when the periodic substrate was added the antenna radiation characteristics improved considerably compared to antennas without the substrate with air holes.

  • DIÓGENES ERMESON DA SILVA PIRES
  • GELOTOPHOBIA AND SOCIAL COGNITION IN ACADEMICS AT UFPA

  • Data: 25/02/2021
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  • “Laughter is the best medicine”, this phrase, commonly used, supports the role of laughter in health and well-being. However, for some individuals with significant traces of gelotophobia, laughter is an emotional expression that harms life, causes shame and must be avoided at all costs. Consistent with this perspective, gelotophobia is characterized as a disorder where subjects with high scores are described as neurotic and introverted, presenting a paranoid tendency to anticipate mockery. Although research on the topic has progressed in the past two decades, the scientific community is investigating the potential achievements of gelotophobia in reaction to eye contact. Previous studies have pointed to difficulties in discriminating the direction of the gaze as the basis for possible misinterpretations of the intentions or mental states of others. The present work examines whether the predisposition to gelotophobia influences the difficulty in discriminating other people's mental states through the interpretation of the gaze. A collection was carried out with the application of two psychometric instruments. The first, the GELOPH <15> self-report questionnaire to analyze traces of gelotophobia and the second, a Revised Mind Reading in the Eyes (RMET) test, a 36-item assessment to analyze the ability to interpret mental states from of facial expressions. Sixty students from UFPA participated in the study, recruited through calls directed to students who identified themselves with anxiety symptoms affecting their academic performance. The results of the study indicated that gelotophobes made more mistakes than non-gelotophobes in the task of gaze discrimination. As expected, the sample scores for gelotophobia exceeded the average when compared to other studies involving samples of healthy individuals with high reliability (α = 0.90). Just as the RMET score was compatible with the literature on reliability (α = 0.66). In addition to the main hypothesis, it was found in the second test that gelotophobes were more likely to have difficulties in the task of social cognition when separating certain stimuli by blocks of emotional valence. Therefore, statistically, the two proposed tests were relevant in the task of understanding eye contact and the influence of fear of being ridiculed in a task of discriminating the gaze.

  • YAGO GOMES DA CONCEICAO
  • NUMERICAL ANALYSIS OF SPR SENSOR IN SPCE CONFIGURATION BASED ON TWO LAYER GRAPHENE BY FINITE ELEMENT METHOD

  • Data: 25/02/2021
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  • In this dissertation, we present a proposal for a surface plasma resonance sensor (SPRsensor) in the surface plasma coupled emission configuration (SPCE) based on two layers ofgraphene. The numerical analysis of the sensor is performed by the Finite Element Method,where the near and far fields in the sensor structure are calculated. The model consists of amultilayer structure: Air/ Graphene/ SiO2/ Graphene/ Prism BK7, with an infinitesimalhertzian dipole operating in the Terahertz range with λ ≈ 250μmsimulating the analytes (which behave like re-irradiating particles) to be detected in the sensor’s output response.Graphene layers are modeled as current surface densities Js0 with conductivity described bythe Kubo Formula. At first, a comparative approach is made between the model proposedin the THz range and a reference model in the optical range. Then, two parametricanalysis of the near and far field are performed: one as a function of the chemical potential (μc = 0 eV, 0.3 eV, 0.4 eV, 0.5 eV e 0.6 eV) applied to the graphene layers. In the secondanalysis, the dipole’s orientation is set at θ = 0°, 45° e 90° while the dipole’s heightregarding to the sensor’s surface is changed by h ≈ 8 μm, 40 μm and 80 μm for each ofthe orientations, where we verify the coupling of TM waves in the prism region and itsimprovement in the sensor’s directivity and sensitivity, implying that graphene improvessensors in the SPCE configuration.

  • PAULO RODRIGUES AMARAL
  • NUMERICAL ANALYSIS OF NANOANTENNA ARRAYS APPLIED TO EFFICIENT WIRELESS NANOLINKS

  • Data: 24/02/2021
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  • In the present work, is analyzed theoretically, an arrangement of plasmonic optical nanoantenna applied to wireless optical nanolink. The antenna is composed of a dipole, three directors and a reflector forming a nanoantena Yagi-Uda. The modeling of the antenna and its application was made using the software COMSOL Multiphysics. For the nanoantenna, the input impedance, directivity, gain, radiation efficiency, reflection coefficient, radiation diagram, and the effect of a silicon dioxide (SiO2) truncated substrate on the resonant properties of the antenna are investigated. For the nanolink, a comparative analysis is made of links formed by Yagi-Uda and dipole antennas in three situations, the first with nanoantennas positioned in free space, a second with as nanoantennas on top of the semi-infinite substrate of SiO2, and a third with nanoantennas on top of a semi-infinite truncated substrate of SiO2. Where we investigated the effect of the truncated substrate on the transmission power and on the near electric field for the Yagi-Uda/dipole, Yagi-Uda/Yagi-Uda and dipole/dipole nanolinks. The results showed that for the three links, the situation in which the antennas are positioned on top of the semi-infinite substrate of SiO2 presented the best power transmission performance. In addition, the three links in the three situations can operate with good power transmission around 170 THz, which is of great importance for future applications in nanoscale wireless communication.

  • SAMILLE CRISTINA PIEDADE COSTA
  • CÁLCULO DE PERDAS TÉCNICAS E NÃO TÉCNICAS EM REDES DE DISTRIBUIÇÃO: UMA ANÁLISE COMPARATIVA ENTRE AS METODOLOGIAS DA ANEEL E DA IMPEDÂNCIA EQUIVALENTE OPERACIONAL

  • Data: 23/02/2021
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  • Agência Nacional de Energia Elétrica (ANEEL) vem desenvolvendo ao longo dos anos uma metodologia única e original para o tratamento regulatório das perdas de energia no Brasil, tratando em regulações distintas as perdas técnicas e as perdas não técnicas. As perdas técnicas são calculadas de acordo com os procedimentos definidos no Módulo 7 dos Procedimentos de Distribuição de Energia Elétrica no Sistema Elétrico Nacional (PRODIST), cuja metodologia consiste basicamente no cálculo do fluxo de carga utilizando informações extraídas do banco de dados da distribuidora, considerando modelos específicos para elementos do sistema como medidores e ramais de ligação. Já as perdas não técnicas, são calculadas de acordo com as regras descritas no Submódulo 2.6 dos Procedimentos de Regulação Tarifária (PRORET). Diversas metodologias foram objeto de estudo no setor elétrico com objetivo de realizar o cálculo das perdas técnicas e não técnicas, soluções que envolvem desde fluxo de carga até o uso de ferramentas de inteligência computacional. Neste sentido, esta dissertação tem como objetivo fazer uma análise comparativa entre a metodologia de calculo de perdas desenvolvida pela ANEEL e a Metodologia da Impedância Equivalente Operacional (IEO), método que possibilita calcular com boa precisão e baixo custo computacional as perdas técnicas e não técnicas em redes de distribuição sob diferentes condições operativas. Os algoritmos de cálculo foram implementados no software Open Distribution System Simulator (OpenDSS) e foram realizadas simulações em um alimentador real pertencente à área de concessão da distribuidora de energia do Estado do Pará, para a verificação do cálculo de perdas técnicas e não técnicas.

  • DANIEL VICTOR TEIXEIRA LIMA
  • A HEURISTIC FOR OPTIMIZING DATA COMMUNICATION NETWORKS TO SUPPORT THE IMPLEMENTATION OF SMART GRIDS

  • Data: 19/02/2021
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  • The resource allocation optimization problem is described as the distribution of resources obeying a set of restrictions imposed by the applications to be implemented in each scenario. From there, the construction of analytical and heuristic models combined with computer simulations is necessary to assess the operational viability of scenarios that have critical requirements for their applications. In this context, a graph model was used to formalize the network optimal resource location problem presented, which in turn was solved through a genetic algorithm that takes into account the expected QoS for Smart Grid applications. The proposal is efficient as it finds an economically viable topology that meets the technical requirements.

  • ANDRÉ PINTO LEÃO
  • LEVANTAMENTO EXPERIMENTAL DE CURVAS CARACTERÍSTICAS DE FALTAS DE ALTA IMPEDÂNCIA NAS SUPERFÍCIES DE MAIOR OCORRÊNCIA PARA REDES AÉREAS DE DISTRIBUIÇÃO

  • Data: 10/02/2021
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  • O presente trabalho apresenta o levantamento experimental de diversas curvas características de faltas de alta impedância (FAI), em redes aéreas de distribuição, nas superfícies onde sua ocorrência é mais frequente, sendo estas informações essenciais para um dos métodos mais proeminentes atualmente utilizados para modelagem deste tipo de falta. Nele são apresentados testes experimentais ocorridos em uma Fonte Ressonante, os resultados iniciais obtidos e a avaliação complementar do uso deste equipamento para o objetivo proposto. Registra o projeto e a montagem de um laboratório para testes experimentais de faltas de alta impedância (FAI) em redes aéreas de distribuição, o único trifásico localizado em toda a bibliografia verificada, onde as principais características de FAI foram confirmadas em diferentes superfícies. Detalha testes inéditos realizados em quatro diferentes tipos de galhos de árvores, onde foram obtidos registros de muitas características conhecidas da FAI. Confirma as condições de ocorrência da FAI e a presença de suas características em superfícies classicamente testadas como a terra, a areia, o seixo, entre outras, possibilitando a obtenção das curvas características da maioria delas. Por fim, o trabalho apresenta às comunidades acadêmica e científica resultados inéditos aos estudos da FAI, uma estrutura única e versátil chamada LABFAI, a qual pode se utilizada para ampliar o conhecimento deste tipo de falta, já que possibilita a realização de experimentos em diversas condições reais de ocorrência, mas que por questão de estrutura e ou conveniência ainda não foram testadas.

  • MAICKSON PATRICK VIANA LEAO
  • ESTRATÉGIAS DE CONTROLE DIGITAL DOS TIPOS POSICIONAMENTO DE PÓLOS E IMC APLICADAS AO PROBLEMA DE REGULAÇÃO DE TENSÃO EM CONVERSOR BUCK DE 5KVW

  • Data: 03/02/2021
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  •  Os conversores de potência CC-CC possuem um amplo leque de  aplicações nas áreas industriais, de energia, e veicular. Possuem características não lineares devido a variação paramétrica de seus componentes e do ponto de operação. Além disso, o acoplamento com outros subsistemas de conversão resulta em consequências diversas, entre elas, o aparecimento de cargas de potência constante. O que abre precedentes para pesquisas relevantes nesta área. Nste trabalho, implementa-se um sistema conversor CC-CC abaixador na topologia Buck para regular um Elo CC que, por sua vez está acoplado a outros dois conversores. Este elo é controlado por modulação de largura de pulso (PWM), a fim de atenuar os problemas já mencionados e somar na construção de uma base documental para pesquisas futuras. Desta forma, considerando-se como uma boa prática de projeto, realizou-se primeiramente a construção de um ambiente de simulação não linear que permita a identificação e modelagem da dinâmica de um sistema conversor do tipo Buck. E assim, encontrar um modelo prático que possibilite o projeto e implementação de controladores digitais testados ainda em ambiente de simulação como requisito obrigatório para posterior implementação em ambiente experimental. As técnicas de controle digital, embarcadas através de equações de diferenças no microcontrolador, são do tipo PID e projetadas através de dois métodos diferentes. O primeiro método é técnica de posicionamento de pólos, implementada a uma estrutura canônica RST no domínio de tempo discreto. A segunda consiste em uma técnica de Controle de Modelo Interno (IMC), de ordem aumentada pela sintonia de um filtro derivativo. Ambas são projetadas a fim de obterem-se boas condições de desempenho e robustez diante das não linearidades da planta e diferenças entre modelo e processo. Utiliza-se de índices integrais, ISE e ISCS, para a análise quantitativa e comparação de desempenho entre os controladores. Assim como de análises gráficas para comparação das curvas de resposta inerentes a cada ação de controle.


     

  • CLEVERSON VELOSO NAHUM
  • THE CONNECTED ARTIFICIAL INTELLIGENCE (CAI) TESTBED FOR EXPERIMENT WITH 5G VIRTUALIZED NETWORKS

  • Data: 29/01/2021
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  • The fifth-generation (5G) cellular networks incorporate a large variety of technologies in order to address very distinct use cases. Assessing these technologies and investigating future alternatives are complicated when one relies only on simulators. 5G testbeds are an important alternative to simulators and many have been recently described, emphasizing aspects such as cloud functionalities, management and orchestration. This dissertation presents a 5G mobile network testbed with a virtualized and orchestrated structure using containers, which focuses on integration to artificial intelligence (AI) applications. The presented testbed uses open-source technologies to deploy and orchestrate the virtual network functions (VNFs) to flexibly create various mobile network scenarios, with distinct fronthaul and backhaul topologies. Distinctive features of the testbed are its relatively low cost and the support to using AI for optimizing the network performance. The dissertation explains how to deploy the testbed structure and reproduce the presented results with the provided code. AI-based radio access network~(RAN) slicing and VNF placement are used as examples of the testbed capabilities.

  • LAURO BRITO DE CASTRO
  • ACCESS NETWORKS BASED ON OPEN SOFTWARE AND HARDWARE TECHNOLOGIES. CASE STUDY IN 2G, 4G AND 5G CELLULAR NETWORK IMPLEMENTATIONS

  • Data: 29/01/2021
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  • The success of mobile networks has driven the commercialization of a new generation standardized by 3GPP approximately every ten years. However, the scope of applications and the requirements for the fifth generation (5G) network stand out when compared to those of predecessors. While the first two generations focused mainly on voice transmission, the others started to include data services and boost markets such as vehicular networks, UAV, IoT (Internet of things) and Industry 4.0. This paper presents the implementation of access networks, based on second generation (2G) features through the CELCOM Project and fourth and fifth generation (4G and 5G) through the PA5Ge network, on the campus of the Federal University of Pará (UFPa). The networks meet the 3GPP standards using open source software projects, Software Defined Radio (SDR) equipment and licensing for operation for scientific and experimental purposes in the 900 MHz and 700 MHz band, respectively. Preliminary assessments demonstrate the operation of the CELCOM network in the target locations through calls, message exchange services and signal level tests. In Pa5Ge, which has modern features such as the virtualization of network functions (VNFs) and centralized radio-access architecture (C-RAN), the traffic generated by emulated users connected to the cellular network is demonstrated, the operation information of the network, eNB configuration, container management tests and traffic analysis. In this context, the main contribution of this work is to describe the projects and stages for the implantation of the networks and their operation, from licensing aspects to technicians, in order to promote similar initiatives to establish platforms for experimental research and also in the scope of humanitarian engineering through telecommunications.

  • JONATA PAULINO DA COSTA
  • RECURRENT NEURAL NETWORK LSTM FOR CLASSIFICATION OF CRIME INDICATOR TWITTERS IN THE CITY OF BELÉM DO PARÁ

  • Data: 29/01/2021
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  • Twitter has become a great source of research data for knowledge discovery, being a social network that disseminates, in addition to personal information, it is possible to share opinions and information about events in general. Considering this, the present study aims to develop a classifier in order to analyze and identify criminal and non-criminal tweets. The Recurrent Neural Network Long Short-Term Memory (RNN – LSTM) was tested for this classification process. For the execution of the algorithm, it was necessary to create a database, since there are no studies or databases available related to the classification of news tweets in crime or not, they were collected from newspaper accounts in the city of Belém and classified manually , containing 6000 records. The results obtained with the use of RNN - LSTM proved to be quite satisfactory for the chosen domain. Based on the results of this research, we observed the effectiveness of the RNN classifier (LSTM) reached the F1 score value of 98%, accuracy of 81% and coverage of 83%. With the results obtained, it can be analyzed that the Recurrent Neural Network (LSTM) is the efficient and satisfactory classifier model for the classification process of tweets related to crimes.

2020
Descrição
  • NAJMAT CELENE NASSER MEDEIROS BRANCO
  • ANÁLISE PROBABILÍSTICA DA CONEXÃO DE SISTEMA DE GERAÇÃO FOTOVOLTAICA EM ESTAÇÕES DE RECARGA DE VEÍCULOS ELÉTRICOS CONSIDERANDO ASPECTOS TÉCNICOS, ECONÔMICOS E AMBIENTAIS

  • Data: 22/12/2020
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  • ANÁLISE PROBABILÍSTICA DA CONEXÃO DE SISTEMA DE GERAÇÃO FOTOVOLTAICA EM ESTAÇÕES DE RECARGA DE VEÍCULOS ELÉTRICOS CONSIDERANDO ASPECTOS TÉCNICOS, ECONÔMICOS E AMBIENTAIS

  • SUELENE DE JESUS DO CARMO CORREA
  • NON-INTRUSIVE LOAD MONITORING SYSTEM USING STACKED NEURAL NETWORKS AND NUMERICAL INTEGRATION

  • Data: 22/12/2020
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  • Population growth and new consumer needs, among other factors, have lead to growing energy demand, without a concomitant increase in energy generation. This way, reduction and rationalization of energy consumption, especially by residential users, have become a global concern generating a need for developing techniques for efficient management and distribution of the available energy. Non-Intrusive Load Monitoring (NILM) techniques have provided valuable information about energy consumption for power generation companies as well as consumers. Such information is important  for making decisions related to sustainable use of energy resources. This study proposes an automated system based on Artificial Neural Network for performing some of the NILM tasks. A stacked neural network was developed to extract features of power signals of appliances to identify those in operation during a given period. This information is then used to disaggregate individual appliance loads through the total aggregate signal, and consumption is calculated through numerical integration. The system was tested using real data from two databases about appliances with On/Off, multi-level, and variable consumption patterns collected in low frequency. The performance metrics, resulting from identification and disaggregation tasks, demonstrate the efficiency of the proposed system.

  • ANDREY RAMOS VIEIRA
  • INCORPORAÇÃO DE RESTRIÇÕES DE PROTEÇÃO AO PROBLEMA DA RESTAURAÇÃO DE SERVIÇO EM REDES DE DISTRIBUIÇÃO RADIAIS

  • Data: 18/12/2020
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  • INCORPORAÇÃO DE RESTRIÇÕES DE PROTEÇÃO AO PROBLEMA DA RESTAURAÇÃO DE SERVIÇO EM REDES DE DISTRIBUIÇÃO RADIAIS

  • IGOR ANTONIO AUAD FREIRE
  • 5G FRONTHAUL SYNCHRONIZATION VIA IEEE 1588 PRECISION TIME PROTOCOL: ALGORITHMS AND USE CASES

  • Data: 17/12/2020
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  • Fronthaul networks have evolved substantially to meet the demands of fifth-generation (5G) cloud radio access networks. In particular, the industry has converged to Ethernet as the main transport technology, with fronthaul-specific encapsulation protocols running on top of it. Since traditional Ethernet is asynchronous and does not support timing distribution, clock synchronization protocols such as the IEEE 1588 precision time protocol (PTP) have gained a fundamental role in the operation of the 5G fronthaul. This work thoroughly analyzes the challenges for PTP-based synchronization in this context, with particular focus on the so-called partial timing support (PTS) scenario, where some network elements do not actively contribute to PTP’s operation. The fundamental problem of PTS is that the network imposes a harsh environment for accurate clock distribution, primarily due to the packet delay variation. As a result, non-conventional strategies have to be exploited to process PTP timing signals. This work explores various estimation strategies for this scenario. Furthermore, it describes an experimental Ethernet fronthaul setup based on field-programmable gate arrays (FPGAs), which was developed to evaluate the synchronization algorithms. In the end, it also investigates practical 5G use cases for synchronized timing signals that were implemented in the testbed.

  • ALEX DE SOUZA VIEIRA
  • PRODUCTION AND EVALUATION OF AN EDUCATIONAL PROCESS FOR HUMAN–COMPUTER INTERACTION (HCI) COURSES

  • Data: 27/11/2020
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  • This work presents a teaching and learning process for Human–Computer Interaction(HCI) courses, combining traditional lecture-based classroom, active learning and Project Based Learning elements, such that students can increase their understanding over HCI. In undergraduate science computing, the academic curriculum is composed of theoretical and practical courses. The theoretical courses address more abstract content. This process intends to increase the envolving of students over the theoretical discipline of HCI. This work shows a different approach to improve student retention for a better understanding of the theoretical aspects over HCI. This proposed process has three mainstages and, as newness, uses the t-learning concept to simulate interactive educational videos. In the first stage, the teacher presents concepts of HCI using traditional lecture-based classroom. The second stage is active learning, where students make oral presentations or make of learning objects based on interactive videos to reinforce their self-comprehension over theoretical content. The third stage is the PBL activity of the production of new learning objects based on interactive videos. The results show higher statistical scores using the proposed method in comparision with the traditional lecture-based classroom used in HCI course. A total of 131 students concepts were compared in this work, that uses traditional lecture-based classroom, with 113 students concepts that use the proposed method. The results indicate that there are advantages in proposed method, because it helps reduce the number of reproved students and increases the average students grade.

  • HOSAIAS ALVES DOS PRAZERES SILVA
  • CONTRIBUIÇÃO DA GERAÇÃO SOLAR FOTOVOLTAICA NA CERTIFICAÇÃO DE EDIFICAÇÕES PÚBLICAS PELO RTQ-C E EM EDIFÍCIOS DE ENERGIA ZERO: LABORATÓRIO DE ENSINO DA UNIVERSIDADE FEDERAL DO PARÁ

  • Data: 30/10/2020
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  • Esse trabalho apresenta a contribuição da geração solar fotovoltaica como fonte renovável na metodologia para obtenção de Etiqueta Nível A em certificação de Eficiência Energética e para a transformação em Edifício de Energia Zero, sendo aplicável a edificações e laboratórios de ensino públicos. O passo-a-passo da metodologia consiste essencialmente em duas etapas: a primeira, através de um diagnóstico energético da edificação analisada seguindo as diretrizes estabelecidas no Regulamento Técnico da Qualidade em Edifícios Comerciais, de Serviços e Públicos – RTQ-C, resultando numa proposta de melhoria energética, financeira e ambiental processada com o auxílio do software RETScreen®; e a segunda, dimensionando um sistema de geração solar fotovoltaica, a partir de dados de medição local e do software Meteonorm®, como bonificação para obtenção da Etiqueta Nível A dos níveis do RTQ-C e com capacidade de produção de energia que torne o balanço energético da edificação positivo, tornando-a um Edifício de Energia Zero. A fim de contextualizar a relevância do trabalho e atualizar o leitor no estado da arte aplicável à metodologia, é apresentada uma revisão bibliográfica direcionada aos benefícios da Eficiência Energética nas edificações públicas e ao RTQ-C; ao cenário atual, aplicação e contribuição da Energia Solar Fotovoltaica no desenvolvimento sustentável, na obtenção de classificações reconhecidas nacional e internacionalmente para edifícios públicos; e aos conceitos atualmente utilizados pela comunidade acadêmica para caracterização de Edifícios de Energia Zero. A revisão bibliográfica e a metodologia foram aplicadas em estudo de caso do Laboratório de Engenharia Elétrica e Computação – LEEC, situado no Campus Guamá da Universidade Federal do Pará, com apresentação dos resultados energético, financeiro e ambiental, mostrando ser uma inovação a ser aplicada em instituições e edificações públicas que possuam espaço disponível e infraestrutura semelhante à do LEEC.      

  • CLEONOR CRESCENCIO DAS NEVES
  • INVESTIGAÇÃO EXPERIMENTAL DE UM ESTRATÉGIA DE CONTROLE ROBUSTO PARAMÉTRICA APLICADA A UMA MICROREDE CC ALIMENTADA POR GERADORES FOTOVOLTAICOS

  • Data: 30/09/2020
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  • Esta tese apresenta uma proposta da forma direta do controlador digital robusto usando a estrutura do polinômio RST baseado sobre a otimização convexa da esfera de Chebyshev. Para verificar a estabilidade robusta e o desempenho robusto é utilizado uma fonte Fotovoltaica formando uma microrede. Para esta abordagem foi utilizado um conversor buck DC-DC.  E também é apresentada a modelagem matemática da planta fotovoltaica e simulação no ambiente do MATLAB para uma análise de seu desempenho na geração de energia elétrica em malha aberta fechada. Esta metodologia levou em consideração os parâmetros de incertezas e a restrição da esfera de Chebyshev que garante o desempenho robusto e a estabilidade robusta do sistema no domínio discreto. Para este fim, um modelo matemático para o conversor Buck DC DC foi considerando com as incertezas das variáveis elétricas, tal como cargas resistivas, indutância, capacitância e variação da fonte de tensão, e para obter o modelo discreto o modelo discreto do sistema foi usado a transformação bilinear. A metodologia proposta é comparada com duas outras projetadas no domínio discreto: Alocação clássica de polos e a metodologia robusta baseada no teorema de Kharitonov. Foram realizadas várias etapas de experimentação para avaliar o comportamento da metodologia de controle quando o sistema foi submetido a variação paramétrica da carga resistiva e variação do set point de tensão. E por fim, o resultado mostra que a metodologia proposta superou as outras abordagem em 90% dos testes e garante a estabilidade robusta e o desempenho robusto quando o sistema é submetido a uma família de incertezas paramétricas.

  • MOISES FELIPE MELLO DA SILVA
  • MACHINE LEARNING AND COMPUTER VISION TECHNIQUES FOR DAMAGE DETECTION AND MODAL ANALYSIS

  • Data: 28/09/2020
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  • As the structural health monitoring (SHM) process evolves from research to practice new challenges arise from their practical implementations. Normal variations in the structure's dynamics caused by operational and environmental conditions are still one of the biggest challenges for real applications of automated monitoring systems. In those cases, the normal variability can mask the existence of damage or blur the severity of damage occurrence. In the context of SHM applications, data normalization is referred to as the process of filtering these normal effects to provide a proper evaluation of the structural health condition and, although the number of approaches for normalization is growing fast, most of them still imposing serious limitations for deployment in real-world monitoring campaigns, mainly related to constraints regarding the data distribution and model parameters, which in many cases still not producing an adequate damage detection performance. On the other hand, a growing number of applications require autonomous non-contact approaches for vibration-based monitoring, pushing efforts into the development of vision-based techniques for modal analysis and modal identification, which can be coupled with machine learning algorithms for real-time dynamics monitoring. Despite some recent and impressive applications of computer vision techniques for SHM, the majority of works still relying on the positioning of speckle or high-contrast markers over the surface of the structure, which can greatly reduce their range of applicability. Therefore, as major contributions, the present thesis addresses the development and proposes novel output-only approaches for data acquisition, modal analysis and damage detection based on computer vision and machine learning techniques, capable of blindly identify high-resolution full-field vibration modes from video measurements only, detect and potentially quantify the damage level in structures of arbitrary complexity. First, machine learning algorithms are proposed for intelligent vibration-based damage detection on accelerometer data. A deep autoencoder is designed to autonomously learn the normal vibration condition of a monitored structure and then identifies damaged conditions from changes in the modal (natural) frequencies. Additionally, a cluster-based technique is introduced to classify different undamaged and damaged conditions of a structure, providing useful insights on the structural behavior. This straightforward clustering procedure automatically discovers the optimal number of clusters representing the main state conditions of the structural system without requiring any manual parameter setting. Second, techniques for blindly identify full-field high-resolution mode shapes and other modal parameters from video measurements only are introduced to performing 2D modal analysis using commercial cameras, with application on bench-scale laboratory structures and for other problems involving 2D wave decomposition. Additionally, it is introduced the first approach to date for efficient and extremely high-resolution 3D structural dynamic modal analysis from dynamic point cloud data acquired using a commercial, low-cost, time-of-flight imager. Solutions to the blind source separation problem are employed to estimate high-resolution 3D mode shapes, modal coordinates, and resonant frequencies using a modified version of the technique employed for the 2D case. It is demonstrated that the proposed approaches have the potential of being general-purpose ones, capable of performing modal analysis and monitoring of amorphous structures. All proposed techniques are validated on laboratory experiments and real-world vibration monitoring datasets to demonstrate their ability to perform the monitoring of varied forms of structures under different conditions and scenarios. Keywords: Video-based dynamics monitoring, Non-contact measurements, Damage-sensitive feature extraction, Stacked autoencoders, Blind source separation, Output-only modal analysis, Damage identification

  • RODRIGO LISBÔA PEREIRA
  • TEORIA DOS JOGOS E INTERAÇÃO SOCIAL AUTO ADAPTATIVA PARA CONTROLE DE PRESSÃO SELETIVA E RECOMBINAÇÃO EM ALGORITMOS GENÉTICOS PARALELOS

  • Data: 09/09/2020
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  • TEORIA DOS JOGOS E INTERAÇÃO SOCIAL AUTO ADAPTATIVA PARA CONTROLE DE PRESSÃO SELETIVA E RECOMBINAÇÃO EM ALGORITMOS GENÉTICOS PARALELOS

  • ALLAN DOS SANTOS BRAGA
  • MODELOS DE RÁDIO PROPAGAÇÃO BASEADOS EM MACHINE LEARNING USANDO PARÂMETROS GEOMÉTRICOS PARA PERCURSO MISTO CIDADE-RIO

  • Data: 04/09/2020
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  • MODELOS DE RÁDIO PROPAGAÇÃO BASEADOS EM MACHINE LEARNING USANDO PARÂMETROS GEOMÉTRICOS PARA PERCURSO MISTO CIDADE-RIO

  • HAROLDO GOMES BARROSO FILHO
  • METODOLOGIA TRADE OFF EM ALGORITMOS DE RASTREAMENTO PARA EXTRAÇÃO DE PADRÕES EM DISTÚRBIOS DA FALA

  • Data: 03/09/2020
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  • METODOLOGIA TRADE OFF EM ALGORITMOS DE RASTREAMENTO PARA EXTRAÇÃO DE PADRÕES EM DISTÚRBIOS DA FALA

  • HELIO RENATO OEIRAS FERREIRA
  • ULTRA BROADBAND FSS DESIGN AND SYNTHESIS FOR SATELLITE COMMUNICATION SYSTEM APPLICATIONS USING MULTIOBJECTIVE NATURAL OPTIMIZATION

  • Data: 24/08/2020
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  • A evolução da computação tem possibilitado avanços substanciais em pesquisas relacionadas à engenharia e em projetos industriais. Nestas áreas, o emprego de ferramentas computacionais tem se intensificado para simulação e obtenção de determinados parâmetros do projeto. No entanto, a crescente demanda por precisão e o aumento gradativo da complexidade das estruturas e sistemas, resulta num processo de simulação cada vez mais demorado, pois a avaliação de um único critério pode consumir várias horas, bem como vários dias ou até mesmo semanas. Logo, um método que minimize o tempo de simulação e otimização, pode, assim, economizar tempo e dinheiro. Nesse contexto, a computação bioinspirada (bioinspired computing - BIC), se apresenta precisa e eficiente, onde muitos métodos computacionais tradicionais falham e, consiste em novo mecanismo para suprir tais dificuldades. Assim, neste trabalho, é realizado um estudo acerca de alguns dos algoritmos BIC mais utilizados na atualidade para projeto e otimização de problemas gerais na engenharia e na indústria. Doravante, se vislumbra desenvolver um código de otimização meta-heurístico multiobjetivo que apresente menor custo computacional e, consequentemente, menor tempo para processamento dos dados. Inicialmente, é realizada uma investigação eletromagnética da superfície seletiva de frequência do tipo losango planar estudada, através de simulações computacionais. A análise numérica é feita usando os métodos FEM com o auxílio de software comercial. O processo de síntese consiste em sintonizar a frequência de ressonância da estrutura e a largura de banda para operação em sistemas de comunicação via satélite, mais precisamente na Banda-X, e Ku. A modelagem das estruturas é realizada por uma rede neural artificial e o processo de otimização é realizado por algoritmos meta-heurísticos. Os resultados obtidos por esses códigos são comparados aos simulados pelo software comercial e aos medidos. Observou-se boa concordância entre os resultados simulados e medidos, bem como uma substancial redução no tempo de processamento da estrutura otimizada.

  • BRUNO NICOLAU MAGALHÃES DE SOUZA CONTE
  • CLUSTERIZAÇÃO, CLASSIFICAÇÃO E PREDIÇÃO DE “PRÉ-EFEITO ANÓDICO” DE CUBA ELETROLÍTICA DE ALUMÍNIO PRIMÁRIO

  • Data: 21/08/2020
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  • CLUSTERIZAÇÃO, CLASSIFICAÇÃO E PREDIÇÃO DE “PRÉ-EFEITO ANÓDICO” DE CUBA ELETROLÍTICA DE ALUMÍNIO PRIMÁRIO

  • GLEISON DE OLIVEIRA MEDEIROS
  • UM FRAMEWORK INTELIGENTE BASEADO EM PREVISÕES DE QOE PARA O BALANCEAMENTO DE CARGA EM REDES 5G

  • Data: 20/08/2020
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  • UM FRAMEWORK INTELIGENTE BASEADO EM PREVISÕES DE QOE PARA O BALANCEAMENTO DE CARGA EM REDES 5G

  • DANIELLE LIMA GUEDES
  • COMPARAÇÃO DE METODOLOGIAS DE AVALIAÇÃO DE EFICIÊNCIA ENERGÉTICA DE EDIFICAÇÕES COM APLICAÇÃO VISANDO O CONSUMO DE ENERGIA QUASE ZERO

  • Data: 14/08/2020
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  • The energy efficiency of buildings is a concept directly related to the efficient use of
    resources, such as energy, water and materials, both in the project phase as in the operation and
    maintenance phase for edifications. Besides providing a possible reduction on operation cost,
    the efficient practices for buildings promote economic, environmental (pollution reduction) and
    human health related benefits. In this context, methodologies able to evaluate and classify the
    energy efficiency of buildings have arised, suggesting the best practices and equipment. In
    Brazil, PROCEL Edifica is responsible for evaluating buildings and emitting a conformity label
    that defines the energy efficiency level achieved by them. In the last two years, the application
    methodology for building evaluation was reformulated and entered in public consultation to
    validate the suggested text changes. Although the text, until present moment, has not been
    validated yet by the appropriate agencies, the new application methodology, named as Instrução
    Normativa INMETRO para a classe de eficiência energética de Edificações Comerciais, de
    Serviços e Públicas (INI-C), has already been used as evaluative method for internal processes
    in the country. The present work has as its purpose applying the INI-C and determining the
    partial energy efficiency level of the air conditioning and lighting systems for a commercial
    building and, then, comparing the results to the energy efficiency level achieved by the previous
    methodology (RTQ-C) for the same building. The distinct results indicate the main
    reformulations in the new methodology of obtaining PBE Edifica label and discuss its
    approximation with other environmental certifications also based on energy consumption for
    classification as, for example, the LEED certification. In order to make the building even more
    efficient, a local electricity generation is proposed in this work, through the insertion of an ongrid photovoltaic system. The local electricity generation is projected to supply 92% of the
    building average consumption, which opens the discussion for the concept of Near Zero Energy
    Building, edifications with high energy efficiency, and the national situation of this topic

  • WELTON VASCONCELOS ARAUJO
  • PLANNING OF NEW MOBILE NETWORKS DEPLOYMENT CONSIDERING RADIO AND TRANSPORT ASPECTS
  • Data: 07/08/2020
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  • PLANEJAMENTO DE IMPLANTAÇÃO DE REDES MÓVEIS DE NOVA GERAÇÃO CONSIDERANDO ASPECTOS DE RÁDIO E TRANSPORTE

  • SUZANE CRUZ DE AQUINO MONTEIRO
  • Multiobjective Optimization Algorithm aiming at Energy Efficiency, with Incremental Cost Reduction, Energy Consumption, Time of Return of Investment and GEE Emissions in a Building

  • Data: 29/07/2020
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  • There are sectors whose electric energy consumption is used mainly in the buildings thermal and luminous comfort maintenance such the residential, public and commercial sector. Its largest loads are air conditioning, lighting and heating systems. In Brazil, the buildings consume up to 51.1% of the electricity annually, according to the BEN 2017 (National Energy Balance - Base Year 2016). Thus, there is a growing interest in studies on buildings energy efficiency including the development of optimization algorithms, especially in the early stages of project design. This article aims to contribute the study of energy efficiency in buildings through a multi-objective optimization software of air conditioning and lighting systems based on genetic algorithms and SPEA II. From the building set by the user, the proposal is to identify an optimum arrangement of lamps and air conditioning units registered in a .csv file for each artificially illuminated and cooled environment in order to reduce the incremental costs of these equipment, its energy consumption in 10 years and the greenhouse gases associated to them, also increasing the energy efficiency level of these systems.

  • ANDERSON SILVA DE OLIVEIRA GÓES
  • PROPOSTA DE PROCESSO PARA AVALIAÇÃO DE DESEMPENHO DE RECURSOS HUMANOS UTILIZANDO TÉCNICAS DE INTELIGÊNCIA COMPUTACIONAL: UMA ABORDAGEM UTILIZANDO CLASSIFICADORES BASEADOS EM REGRAS E ALGORITMOS DE APRENDIZADO SUPERVISIONADO

  • Data: 28/07/2020
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  • PROPOSTA DE PROCESSO PARA AVALIAÇÃO DE DESEMPENHO DE RECURSOS HUMANOS UTILIZANDO TÉCNICAS DE INTELIGÊNCIA COMPUTACIONAL: UMA ABORDAGEM UTILIZANDO CLASSIFICADORES BASEADOS EM REGRAS E ALGORITMOS DE APRENDIZADO SUPERVISIONADO

  • GERALDO SOUZA DE MELO
  • PLASMONIC SWITCHES AND MULTIFUNCTIONAL DEVICES BASED ON GRAPHENE IN THE THZ AND INFRARED RANGES

  • Data: 24/07/2020
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  • New controllable plasmonic devices based on graphene for the terahertz and infrared regions are analyzed in this work. The devices work by propagating plasmonic waves on the graphene surface, and can excite resonances in the structures of the devices. The structures of the filters and plasmonic keys consist of a graphene disk coupled to two waveguides also of graphene, which are perpendicular to each other, whereas the multifunctional devices have a T shape, one with a circular resonator and the other without a resonator, all devices are deposited on silica and silicon. The results for the plasmonic filter, without the application of external magnetic field DC, show three resonant modes: dipole, quadrupole and hexapole, with maximum reflections in the dipole and hexapole modes and maximum transmission in the quadrupole. We analyzed two plasmonic keys, one obtained by applying an external electric field over the filter, allowing us to move regions of maximum isolation to regions of maximum transmission, showing the characteristic of dynamic adjustment of graphene. The other key is obtained by applying an external magnetic field DC on the filter, causing the dipole mode to undergo a rotation of 45, transmitting the signal from port 1 to 2, with rotating resonant modes ω+ , ωand a stationary mode ω0 , due to the degeneracy breaking caused by the external magnetic field. For the multifunctional device with resonator, we have the same results obtained for the filter, with the difference being the new power divider function in quadrupole mode, in addition to the filter functions in the dipole and hexapole. Applying an external voltage to the structure, we can move the dipole and hexapole modes to the quadrupole region, having an electro-optical switch in that region. For the multifunctional device without a resonator, we only have the divider functions and when we apply an external voltage only in the central region of the device, we have an electro-optical switch. Variations of physical and geometric parameters were made and the results were studied analytically, using the Temporal Coupled Modes Theory, to ratify the results found numerically by the COMSOL Multiphysics and HFSS software, showing that the results obtained by the two methods are in good agreement. We analytically show the possibility of choosing the operating frequency range of the devices from the choice of the resonator radius, as well as the dynamic control of the structures through the variation of the chemical potential of graphene.

  • ILAN SOUSA CORREA
  • DIGITAL SIGNAL PROCESSING FOR THE FRONTHAUL OF 4G AND 5G NETWORKS

  • Data: 10/07/2020
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  • Cloud Radio Access Network (C-RAN) is an architecture to decrease implementation costs of mobile networks deployments, in which the traditional basestations are split into the Baseband units (BBUs) and Remote Radio Units (RRU). BBUs are located in datacenters and perform most of the digital signal and network processing. Several BBUs are located in a datacenter, which allows decreasing electricity, connectivity and thermal conditioning costs. RRUs are located at the cell sites and perform a few or no processing, which comprises transmission and reception of signals to interface with users’ equipment. In C-RAN a network segment called fronthaul connects the BBUs and the RRUs, in which, in most of the cases, CPRI protocol is used and allows transporting baseband signals to be transmitted and received baseband signals, resources to synchronize in frequency and time BBUs and RRUs, and control data.

    A consequence of the evolution of the mobile networks is the decrease of the cell radius, due to several factors, such as, the transmission in higher carrier frequencies. This process is known as densification of the mobile networks. Besides, next generation mobile networks have more dependence on multiple antenna techniques, and it results in a significant increase in the fronthaul requirements to transport the signals. Because of that, there is a concern the fronthaul technologies evolution do not follow the evolution of the mobile networks. Therefore, there is interest from industry and academy parties on technologies to make the fronthaul cheaper and more efficient. The result is that many works have investigated technologies for the fronthaul.

    In this context, this thesis investigates digital signal processing techniques that allows more efficient signals transport in fronthaul, for which the transport of frequency-multiplexed analog signals is studied. This form of transmission contrasts with the transport time-multiplexed digitized signals, which is adopted in current technologies such CPRI. The transport of analog signals has potential to decrease significantly the fronthaul bandwidth required to transport the signals in relation to the time-multiplexed digitized transport. However, analog transmission has a drawback of causing distortion in the signals. Specifically, this thesis investigates digital signal processing techniques to allow efficient multiplexing and demultiplexing to be deployed in the BBU and RRU. These techniques are evaluated in relation to the computational complexity and the distortions. It is also distortions caused by the transmission in fronthaul, for which it is proposed a procedure to estimate the signal-to-noise ration of the fronthaul. The signal-to-noise ratio is applied to calculate a pre-emphasis that is applied to the signals before transmission in fronthaul. The techniques are evaluated in experiments of transmission in an optical link. Results are shown as measurements, distortion estimation, and complexity of the algorithms.

  • ALLAN BARBOSA COSTA
  • The use of Active Methodologies for Teaching-Learning Systems in Telecommunications

  • Data: 03/07/2020
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  • Universities have been seeking to adopt active teaching methodologies in their curricular structure, such as Project and Problem Based Learnig (P2BL), together with the use of simulation tools in classes, which facilitate the teaching and learning process, not only for students. engineering students, but all students who need more detailed visual resources to understand the problem addressed. In this sense, this work proposes the use and development of a computational tool for planning Wireless Communications Networks to assist in the teaching of Computer Engineering, Information Systems, Telecommunications Engineering and Electrical Engineering disciplines, using Virtual Reality techniques and the specialized and consolidated literature of the area, for the design of arbitrary scenarios associated with radiopropagation models that simulate the behavior of the signal in different scenarios, in the first outdoor phase and in the second indoor phase. The types of antennas with their respective gains, their polarization and different heights, the frequency of system operation, the power of the transmitter and the equivalent parameters in the mobile unit are considered in the simulator. In this way, it is possible to create outdoor scenarios in this version and indoor and outdoor scenarios in future versions to run the simulation using some of the propagation models defined in the literature. Thus, there is a three-dimensional visualization of the coverage area, intensity of the signal received in a given region of the scenario, shadow area, among others, in a totally virtual environment.

  • ANDRE DE OLIVEIRA FERREIRA
  • PHOTOVOLTAIC-WIND WATER PUMPING SYSTEM WITH CONNECTION AND CONTROL VIA A TWO-INPUT DC-DC CONVERTER

  • Data: 30/06/2020
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  • In this work, a small hybrid photovoltaic-wind water pumping system is modeled and analyzed through computational simulations. In the proposed system, photovoltaic generator and wind generator are connected via a two-input DC-DC converter, whose output is directly coupled to a DC motor-pump. The two-input DC-DC converter makes the use of a battery bank optional, and acts on the sources drained currents simultaneously or individually to operate them at desired points of their characteristic curves. The simulations demonstrate good performance of the system, which it is feasible to be implemented in practice and can be used in remote regions or where necessary.

  • LUCAS DE SOUSA PACHECO
  • MOBILITY AND CLOUD MANAGEMENT IN WIRELESS HETEROGENEOUS 5G NETWORKS

  • Data: 30/06/2020
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  • Mobility management is a key area to ensure connectivity and the continuity of the services consumed by mobile users. This dissertation analyzes how the next generation of 5G ultra-dense networks will pave the way for the distribution of video in vehicular networks (VANETs), which will be composed of a heterogeneous ultra-dense infrastructure, joining existing wireless communication technologies to obtain greater spectral efficiency. A handover algorithm, called HoVe, is the mais contribution of this work. HoVe is an algorithm based on multiple criteria for video distribution on ultra-dense 5G VANETs. The simulation results show HoVe’s efficiency in providing videos with 19 % higher quality than state-of-the-art algorithms, improving the package delivery rate by at least 30%. This work studies a particular case of VANETs that benefits from computing at the edge of the network, the case of Autonomous Connected Vehicles, or CAVs. Edge and mist computing are emerging solutions for remote data processing for autonomous vehicles, offering higher computational power, as well as the low latency required by autonomous driving. This work also proposes the MOSAIC algorithm for service migration and resource management for communication between layers and between layers in edge and fog computing. Simulation results show the efficiency of the proposed algorithm in terms of latency, migration failures, and network throughput.

  • ULISSES WEYL DA CUNHA COSTA
  • A FUZZY STRATEGY FOR PLANNING CENTRALIZED ACCESS NETWORKS IN THE INSTALLATION OF HYBRID FIBER RADIO SYSTEMS

  • Data: 19/06/2020
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  • 5G networks have arrived and are able to shift paradigms within the areas of connectivity, maintainability, scalability and availability. Their aim is to ensure that users can remain online with their devices at any time and in any place. In light of this, solutions for centralized networks are becoming attractive since they are manageable and low-cost. In these conditions, the use of computing techniques such as fuzzy logic benefits the supervision and planning of networks by optimizing and controlling resources as well as managing the system. However, planning a centralized network tends to raise challenges in the optical sectors that are located between the telecommunications center and the base station. Technologies such as radio over fiber are being examined to meet the demands in the fronthaul market, although they raise many other challenges. For this reason, in this study, we have adopted an intelligent strategy to determine in a balanced way what radio over fiber signals should be allocated in the optical sector. This strategy is implemented using fuzzy logic and may be used in decision making to plan the future of centralized networks. The results show that it is possible to make tradeoffs between the capital expenditure and performance of the system.

  • MARCELINO LOPES CORREA DA SILVA JUNIOR
  • IMPROVEMENT OF PLASMONIC NANOANTENNAS FOR CELLS

  • Data: 05/06/2020
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  • Currently, organic photovoltaic systems have performance with very different levels of development, such devices convert sunlight into electricity from organic semiconductors that constitute the active layer of these devices that, generally, are made up of fullerene derivatives and conjugated polymers, having the efficiency increased from the use of silver nanoantennas on this layer. In this study, the optimization of the geometric parameters of nanoantennas and the unitary solar cell was carried out using the finite element method, with the analysis made in the periodic organic solar cell consisting of a reflecting block and a cylindrical nanoantenna formed by the noble metal silver, and the active layer formed by the material P3HT: PCBM, whose representation of the physical characteristics of these materials were modeled from the interpolation of experimental results. The structural configurations of the plasmonic nanostructures and the performance of the device were monitored from the photophysical properties of the system, and as demonstrated from new geometric models of nanoantennas and a nanoantenna array formed by the convex cone nanoantenna together with a pyramidal nanoantenna, there was a better solution for different light incidence angles compared to a single nanoantenna. The location of the nanoanennas was also analyzed to study the absorption behavior in the active layer. Therefore, there was an average increase in the absorption efficiency of this organic solar cell, both for magnetic transverse polarization and for electric transverse polarization, in comparison with the use of conventional nanoantenna in the wavelength range of (300: 800) nanometers.

  • LUIZ CLÁUDIO LOBO DA SILVA JÚNIOR
  • MITIGAÇÃO DE VARIAÇÕES DE TENSÃO EM UMA INDÚSTRIA CERVEJEIRA USANDO BANCO DE CAPACITORES FIXOS E CHAVEADOS

  • Data: 04/06/2020
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  • MITIGAÇÃO DE VARIAÇÕES DE TENSÃO EM UMA INDÚSTRIA CERVEJEIRA USANDO BANCO DE CAPACITORES FIXOS E CHAVEADOS

  • FÁBIO FERREIRA RIBEIRO
  • DESIGN DE ANTENAS PLANARES PARA APLICAÇÕES EM 60 GHZ

  • Data: 29/05/2020
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  • DESIGN DE ANTENAS PLANARES PARA APLICAÇÕES EM 60 GHZ

  • LUCAS DE LIMA BASTOS
  • SID - SISTEMA DE IDENTIFICAÇÃO DUPLA DE USUÁRIOS DE DISPOSITIVOS VESTÍVEIS ATRAVÉS DOS SINAIS DE FOTOPLETISMOGRAMA E DE ELETROCARDIOGRAMA

  • Data: 28/05/2020
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  • Com o crescimento da e-health, os dispositivos vestíveis destacaram-se devido à sua praticidade e conforto na detecção dos dados pessoais. Dispositivos vestíveis em e-Health fornecem acesso de fácil uso, bem como um retorno de informações para o usuário. Em geral, esses dispositivos possuem uma variedade de sensores que capturam várias informações do ambiente e do usuário. As informações mais populares coletadas por smartwatches e pulseiras é sobre a medição de batimentos cardíacos, passos, oxigenação e fotopletismografia (PPG) e eletrocardiograma (ECG). Cada processo com sensores tem ruídos, ondas eletromagnéticas e movimentos que podem interferir ao identificar, analisar e verificar o indivíduo. A partir disso, a filtragem é um passo indispensável em qualquer processo. A identificação é dividida em etapas, e o principal e essencial é a filtragem porque é onde o pré-processamento começa. Esses dispositivos vestíveis dependem de dispositivos móveis para autenticação do usuário. Se o usuário precisar de validação, ele recorrerá a métodos tradicionais em outros equipamentos que possuem sensores de reconhecimento, como íris, rosto ou impressões digitais. Para superar esses problemas, esta dissertação é dividida em duas etapas. A primeira trata do pré-processamento do sinal (captação e filtragem). Segunda etapa trata do modelo de autenticação de pessoas a partir de sinais fotopletismografia (PPG) e eletrocardiograma (ECG)

  • BRUNO SANTANA DE ALBUQUERQUE
  • USE OF ACTIVE METHODS IN THE TRANSFORMATION OF A UNIVERSITY BUILDING INTO THE ZERO ENERGY BUILDING: CASE STUDY OF THE CENTRAL LIBRARY

  • Data: 06/05/2020
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  • This thesis proposes an energetic evaluation of a University Building transformation into the Nearly Zero Energy Building (EEZ), by using active methods such as Photovoltaic System (PV), and presents its application in the form of a case study. The purpose of this study was to analyze the energy balance between the UFPA Central Library, the PV, the distribution system and the storage system, aiming at the load autonomy. Satisfactory results were obtained for different scenarios created by the variability of the load, according to the university calendar, and the intermittency of the photovoltaic generation. The use of the PV generate enough to supply most of the building load, however only 53% of this energy benefited the building, the energy surplus supply others university loads. Therefore, the use of the storage system allows greater use of the photovoltaic energy generated in the building.

  • CAMILO LELIS ASSIS GONCALVES
  • USING DEEP LEARNING AND COMPUTER VISION TECHNIQUES FOR DETECTION AND TRACKING OF COMPONENTS IN MINING TRAIN WAGONS

  • Data: 27/04/2020
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  • The design of automatic inspection systems for the inspection of train wagons and railway  components that can cause derailment is a crucial factor for increasing productivity and safety in industrial environments. We propose a method for the detection and tracking of components of mining train wagons using a detector based on Convolucional Neural Networks and Deep Learning. In our experiments, our focus was on detecting the so called wagon's “super structure” , but the technique can be easily extended to detect other components.

  • FRANCISCO EGUINALDO DE ALBUQUERQUE FÉLIX JÚNIOR
  • Data Science Applied to Public Data: Case Studies on Brazilian Social Security

  • Data: 17/04/2020
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  • Data Science is an interdisciplinary area related to data analysis, which aims to extract knowledge and possible decision-making about specific problems. This topic indicates an evolutionary trend in recent years, due to a large amount of unprocessed data generated daily, encouraging researchers and companies to carry out increasingly complex studies and analyses, assuring scientific advances in various fields, as well as insure competitive advantages on corporations. In this context, open government data, because they repeatedly need pre-treatments and computational methods to process their data sets, present themselves as potential sources of information to be explored taking the Data Science's perspective, allowing the development of strategies each time more efficient and optimized in public management. Given this, and allied to the recent discussions related to the reform in the Brazilian social security, this dissertation presents two case studies referring to analyzes in the national social security system. The first study used the microdata referring to the demographic censuses of 2000 and 2010, made available by IBGE, proposing to evaluate the participation that retirements and pensions have in the income inequality of the population in the years evaluated about Brazilian states and municipalities. For this, the Gini index decomposition methodology was applied to this portion of benefits, dividing them into categories, lower or equal to one minimum wage and above one minimum wage. The results show that, although the analyzed benefits contribute to the Brazil income concentration, the portion corresponding to a minimum wage contributes to the deconcentration of income, and the portion above one salary contributes to the concentration, being a repetitive pattern throughout the country. On the other hand, the second study proposed an evaluation of the impacts caused by the pension reform, which is proposed in PEC 06/2019, For this, a \textit{Data Warehouse} structure was developed, responsible for storing the microdata provided by the Social Security CPI. Thus, applying data batch processing strategies and using the information provided by IBGE and AEPS, was simulated the rules predicted by the reform regarding the pensions granted in the analyzed time interval. After the simulations, it was observed that PEC 06/2019 would hinder access to benefits, in which approximately 83,28\% of the pensions would not have been granted had it been in effect since 1995.

  • DAIYUKI MAIA FUJIYOSHI
  • MODELOS FDTD PARA ANÁLISE DE SISTEMAS DE ATERRAMENTO: DISPERSÃO DO SOLO UTILIZANDO APROXIMADOR DE PADÉ E IONIZAÇÃO DO SOLO CONSIDERANDO MÚLTIPLOS ESTÁGIOS E RESPECTIVAS RESISTIVIDADES RESIDUAIS

  • Data: 03/04/2020
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  • Dois modelos FDTD (Finite-Difference Time-Domain) para solos dispersivos e ionizados, respectivamente, são propostos para representar realisticamente as respostas transitórias dos sistemas de aterramento. O modelo para solos dispersivos é desenvolvido inserindo a dependência da condutividade e permissividade elétrica com a frequência na equação de Maxwell-Ampère através do aproximador de Padé para o termo σ+jωε. A partir disso, são obtidas equações de atualização explícitas para o método FDTD. Ainda, para validar o modelo de solos dispersivos, foram realizados testes experimentais em sistemas de aterramento. No modelo FDTD para solos não lineares, são modeladas quatro fases para a ionização do solo: sem ionização, presparking (primeiro estágio da ionização), sparking (segundo estágio da ionização) e desionização. Mecanismos identificados experimentalmente na literatura para ionização da água são associados com as fases de presparking e sparking da ionização do solo. Com base nisso, deduziu-se que a ionização fraca do gás (fase de presparking) presente dentro das bolhas produzidas devido aplicação de correntes elevadas e a ionização da solução aquosa (fase de sparking) ocorre durante o processo de ionização no solo. Uma função matemática é proposta para representar o crescimento suave da condutividade elétrica em um ponto do solo durante a fase de sparking. Também, sugere-se que, quando os efeitos associados ao crescimento limitado da quantidade de cargas livres e suas mobilidades restritas são consideradas, a resistividade residual deve ser adotada não somente na fase de presparking, mas também durante o estágio de sparking. O modelo FDTD para solos ionizados é validado através da reprodução numérica de experimentos publicados na literatura. Os resultados obtidos através dos modelos FDTD desenvolvidos neste trabalho apresentaram excelente concordância com os respectivos resultados experimentais.

  • RAMON CRISTIAN FERNANDES ARAUJO
  • SISTEMA PARA CLASSIFICAÇÃO AUTOMÁTICA DE DESCARGAS PARCIAIS EM BOBINAS ESTATÓRICAS DE HIDROGERADORES USANDO REDES NEURAIS ARTIFICIAIS E MAPAS PRPD

  • Data: 31/03/2020
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  • Neste trabalho, são propostos uma metodologia e um sistema de classificação de múltiplas fontes de descargas parciais (DPs) em enrolamentos estatóricos de hidrogeradores, utilizando Redes Neurais Artificiais (RNAs). A base de dados é composta de mapas PRPD (Phase-Resolved Partial Discharges) provenientes de medições de DP online de hidrogeradores operando em ambiente real. No trabalho, são propostas as seguintes contribuições: (i) desenvolvimento de nova métrica de desempenho de classificadores, que remove o viés introduzido por distribuições heterogêneas das classes de saída na base de dados; (ii) desenvolvimento de novos atributos extraídos dos padrões PRPD, objetivando facilitar a tarefa de reconhecimento utilizando menos variáveis; (iii) nova técnica de filtragem de padrões PRPDs, os quais são tratados como imagens; e (iv) rejeição de padrões inválidos, contendo apenas ruídos. Tais contribuições foram desenvolvidas ao longo do trabalho considerando dois cenários, de diferentes graus de complexidade. No primeiro, realizou-se o reconhecimento de padrões com uma única fonte de DP, ainda não utilizando a filtragem supramencionada. Atributos baseados no conceito de projeção de imagens são extraídos dos PRPDs, e utilizados como entrada das RNAs para treinamento. Taxas de acerto acima de 94% foram obtidas pela melhor RNA. No segundo cenário, os PRPDs apresentam múltiplas fontes de DP simultâneas. A técnica de filtragem desenvolvida foi aplicada para remoção de ruídos e separação dos múltiplos tipos de descargas. A tarefa de classificação foi decomposta em problemas menores, cada qual solucionado por uma RNA treinada com atributos de entrada específicos. Taxas de acerto globais em torno de 90% foram obtidas para as classes de DP. Por fim, a metodologia também foi validada mediante reconhecimento de DPs em tempo real na Usina Hidrelétrica de Tucuruí, sem quaisquer intervenções manuais.

  • DAYNARA DIAS SOUZA
  • EVALUATION OF GUIDED MODES IN COPPER CABLES FOR DATA TRANSMISSION IN TERABIT PER SECOND

  • Data: 27/03/2020
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  • Copper-based technologies have been using twisted-pair cables as transmission lines, i.e., exploiting the TEM (Transverse Electromagnetic) mode to transmit data. However, the use of ever-higher frequencies drastically increase the attenuation of the TEM mode, limiting the reach and the achievable data rate of the system. On the other hand, a recent work propose a new approach for exploiting the transmission capacities of those cables: use their high-order guided modes. These higher-order TE (Transverse Electric) or TM (Transverse Magnetic) modes arise when the wavelengths associated to the operating frequencies are smaller than the cross-sectional dimensions of the cable. When using twisted pair cables as waveguides, the possibility of achieving transmission rates of the order of Terabit per second was envisaged, assuming that the model of the surface guided mode of a single bare-wire, known as the Sommerfeld line, properly describes the attenuation of the higher order guided modes of a twisted pair. However, it is evident that Sommerfeld model is unappropriated since the pairs of a copper cable exhibit a physical structure much more complex. This work investigates the propagation of various guided modes in twisted pair cables, from numerical simulations in HFSS software, considering real constructive characteristics such as pair twisting and conductor and insulator materials. The use of higher-order guided modes on coaxial cables is also evaluated. Based on the results obtained, it is also determined the aggregate data rate of each cable as a waveguide via Shannon’s capacity. The results show that there are around 20 propagation modes available on each cable up to 300 GHz. Data rate results show that, for 10 meters, it is possible to reach more than 1 Tbps on just one twisted pair, up to 3 Tbps on a four-pair twisted cable and approximately 0.5 Tbps in a coaxial cable.

  • LENO RODRIGUES MARTINS
  • DEVICES BASED ON BIDIMENSIONAL PHOTONIC CRYSTALS AND COUPLED MODE THEORY FOR PHOTONIC COMPONENTS WITH MAGNETIC SYMMETRY

  • Data: 26/03/2020
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  • In this work two new communication system devices are presented, consisting of a T-junction of three waveguides based on a 2D photonic crystal with square lattice. One waveguide is the input port, while the other two serve as output ports. The first component can fulfill three functions: it can switch OFF the two output ports; can be used as a 3 dB divider of input power; and, it can switch ON any one of the two output ports. Changing the operating regime is achieved by a DC magnetic field that magnetizes a ferrite resonator located at the intersection between the waveguides. The second component, on the other hand, performs the circulation of electromagnetic signals, for which a comparative study of the operation was performed for the dipole and quadrupole resonance modes. In addition, an approach based on the theory of coupled temporal modes for the analysis and design of electromagnetic components with low symmetry was developed, which was applied in the study of a W circulator.

  • BRENDA PENEDO TAVARES DE SOUSA
  • COUPLING GUIDED MODES IN TWISTED PAIR CABLES USING RADIAL SYMMETRY ANTENNAS IN THE TERABIT DSL SCENARIO

  • Data: 26/03/2020
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  • The development of data transmission standards and access technologies has always been linked to the need to supply high data rates. Thus, technologies already implemented, such as the DSL (Digital Subscriber Line) system that uses twisted pairs for transmission, have been adjusting to support this growing data demand. However, twisted pairs, as well as all physical medium of propagation in DSL systems, are used as a transmission line, using the transverse electromagnetic mode (TEM). However, the physical limitations of the twisted pair as a transmission line prevent the system from reaching speeds in the ranges of Terabit per second. So, recently, the use of twisted pairs as a waveguide, as an alternative to the transmission line mode, is already the object of study and brings with it the possibility of further increasing the data rate in this available infrastructure. However, one of the challenges for this implementation is the coupling of the guided modes in the twisted pair, which are very complex structures compared to the most used waveguides. In this scenario, this dissertation aims to evaluate the coupling of the radiated signal between an antenna with radial propagation and the twisted pair cable, analyzing which antenna structure is more compatible with the twisted pair cable. Considering that neither the structure of the twisted pair as the twisted pair cable has a closed analytical model for the behavior of the electromagnetic field in these structures, all the results were obtained from numerical simulations in the HFSS software (High Frequency Structure Simulator), in terms of the antenna scattering parameter and the intensity of the electric field in the twisted pair. With these parameters, it was possible to evaluate the coupling efficiency between the antenna and the waveguide, as well as to evaluate the signal guidance and to predict the transmission rate available to users. In these evaluations, it was highlighted the coupling of the antenna structure with the shielded twisted pair cable, which reached levels of up to 78.85% at frequencies of 0.3 THz, in addition to confirming that despite the use of these cables for data transmission is not as effective as shown in the literature, it is still feasible, since it has been shown from numerical simulations that signal guidance throughout its structure is possible.

  • SANDIO MACIEL DOS SANTOS
  • Data Science Applied to Federal Government Open Data: Case Studies on the Economy of Brazilian Municipalities

  • Data: 13/03/2020
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  •    The data analysis process in recent years has been highlighted in the Brazilian scenario since the granting of Law 12.527/2011, which guarantees access to public information and, therefore, allows greater transparency of public spending for society. Additionally, countless discussions will arise around the Brazilian social security data, such as social security reform. Based on the context of open and public data, two case studies about Brazilian government data are discussed. In both case studies, Data Science techniques are applied, as it possesses interdisciplinary characteristics during its data analysis process. Also, Data Science is a technique easily applicable to different areas of knowledge. Thus, the first case study aims to use statistical analysis to highlight whether social security benefits (retirement payment, pensions, benefits, etc.) paid by the municipalities have the same financial impact between the five major regions of Brazil (Midwest, Northeast, North, Southeast, and South) between 2010 and 2017. The analyzed results point that municipalities that have between 10 and 20 thousand inhabitants, present the biggest deficit in the accounts concerning the collection and transferred amounts. The second case study aims to use the STVAR forecasting model to estimate the behavior of the economic cycle of the municipality of São Paulo through the expenditure, revenue, and GDP variables. The model assessment uses the impulse response function and is used to measure the behavior of the economic cycle after an exogenous shock

  • IGOR WENNER SILVA FALCAO

  • Data: 06/03/2020
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  • O aumento no volume de serviços e aplicações móveis, além do crescimento acelerado das demandas de acesso sem fio, representam desafios significativos para a próxima geração de redes móveis, a quinta geração (5G). Esse aumento no volume de aplicações é reflexo do crescente número de dispositivos que estão conectados à rede, consumindo de maneira desordenada e gerando alta carga de dados. Outro ponto de grande impacto no comportamento do fluxo de dados é a migração diária em larga escala de pessoas nos centros urbanos, causando o chamdo Efeito de Maré. Este promove a flutuação espaço-temporal do tráfego ao longo do dia, causando um problema para o controle e gerenciamento da rede. O fenômeno de marés provoca ainda outras adversidades, dentre elas há a baixa eficiência no uso dos recursos de hardware, o desbalancemento de carga, a subutilização de recursos e a ociosidade de capacidade de rede. Com base nestas informações e considerando o conhecimento dos operadores de serviços sobre mobilidade de assinantes, dados do movimento de usuários da cidade de Nova York foram extraídos através de uma LBSN (Location-Based Social Network). Considerando a alta demanda de tráfego esperada para o 5G e os problemas oriundos do Efeito de Maré na arquitetura de rede atual, nesta dissertaçaõ é proposta uma heurística com duas abordagens de provisionamento de recursos de hardware (uma baseada na taxa de transferência agregada e outra no número de usuários conectados). Os resultados apontam que o provisionamento de rede atendeu à variabilidade do tráfego do cenário utilizado, minimizando a Probabilidade de Usuário Bloqueado, maximizando a eficiência da Unidade de Banda Base (BBU) e quantificando as Small Cells (SCs) necessárias para atender à demanda dos usuários.

  • ALEX BARROS DOS SANTOS
  • A machine learning framework for ECG biometric systems

  • Data: 28/02/2020
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  • With the new environment of IoT and the deployment of 5G networks, a huge amount of data will be generated. New applications will be created and others will be completely redesigned. In this sense, the demand for health services has increased due to a society greater concern with health and, also, the price decreasing for the acquisition of wearable devices. Moreover, the applications require more data protection and privacy, so, biometrics has become one of the main mechanisms for protecting information used by users in all kid of systems and applications. This work investigates the use of an ECG signal in biometrics systems and the machine learning techniques that could be used in this application. This new signal is an alternative not only to increase current safety standards by providing the individual's continuous authentication but also to assess health with cardiac monitoring already well established in medicine by evaluations. To advance in this area, this dissertation is proposing a framework to build a composed data set from different data sources. Defining techniques for extracting signal considering mobile applications and design a structure that allows the use of ECG as a biometric signal in a scalable and heterogeneous environment considering different machine learning techniques such as Support Vector Machine, Random Forest and Neural Networks.

  • EWERTON CRISTHIAN LIMA DE OLIVEIRA
  • PROPOSAL OF A FRAMEWORK FOR NONLINEAR MULTIVARIABLE DYNAMIC SYSTEMS IDENTIFICATION

  • Data: 27/02/2020
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  • The techniques of dynamic systems identification are algorithms of most importance for generating mathematical and computational models capable to represent the dynamic of systems and processes present in many fields of society, such as: industrial processes; automobiles; food production; aerospace vehicles; biological systems and etc. The identification of these systems, which generally have more than one variable of input and output (multivariable systems) and also are nonlinear, it is very important for science and engineering in relation to the development of new control techniques, fault monitoring and prediction of operating state of these mechanisms. Nonetheless, the identification of nonlinear MIMO (Multiple Input Multiple Output) systems is a hard task, as much due the difficulty of implementing the classic algorithms for solve this problem, as the fact that nonlinear systems require complex models for represent their dynamics in satisfactory way. In order to solve this problem, this work proposes a framework capable of performing as much the identification of nonlinear multivariable dynamic systems in fuzzy TSK model, which can represent in simple way the coupling among the variables involved in identification, as the selection of regressor vector used in model. The framework is tested and compared with RNA and a Hammerstein-Wiener model in identification of two nonlinear MIMO industrial plants:  Continuous Stirred Tank Reactor (CSTR); Industrial Dryer. The comparison of these three techniques is made with base in indices of Mean Squared Error () and Variance Accounted For (), further the analysis of residues between the observed and estimated data. The results show that the proposed framework got the best performance, based in the two indices, in 80% of outputs estimation of the two multivariable plants, and also reached the best performance in 60% of residual analysis of plants identification.

  • NAGIB COELHO MATNI NETO
  • Optimal Gateway Placement Based on Fuzzy C-Means for Low Power Wide Area Networks

  • Data: 27/02/2020
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  • Low Power Wide Area Network (LPWAN) technologies recently gained interest from the research and industrial community. Internet of Things (IoT) devices communicate directly with gateways, which act as bridges towards a central network server and the Internet. In this context, it is important to study how to place multiple gateways in an area considering Quality of Service, Capital expenditure (CAPEX), and operational expenditure (OPEX) requirements. This is because network planning and optimization are considered to be significant issues that impact on the application performance, CAPEX, and OPEX. In this paper, we propose an optimal LoRa gateway placement (PLACE). It considers the Gap statistics method to find the number of LoRa gateway, which is used to compute the gateway placement using the Fuzzy C-Means algorithm. Simulation results show that PLACE reduced in 36\% the CAPEX and OPEX compared to the grid and random gateway placement, while keeps a similar Packet Delivery Ratio.

  • VITOR DOS SANTOS BATISTA
  • ANÁLISE DE DESEMPENHO DE METAHEURÍSTICAS APLICADAS AO PROBLEMA DE RESTAURAÇÃO DE REDES DE DISTRIBUIÇÃO

  • Data: 20/02/2020
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  • Nos últimos anos diversas meta-heurísticas foram utilizadas para solucionar o problema de restauração de Sistemas de Distribuição de Energia (SDE) de forma eficiente. Dentre elas destaca-se o Algoritmo Evolutivo Multiobjetivo por Tabela (AEMT), que juntamente com a utilização da Representação Nó-Profundidade (RNP), trouxeram um grande avanço na área pois a RNP sendo utilizada como estrutura de dados é possível realizar modificações na topologia do SDE sem perder a radialidade e restabelecer o fornecimento de energia para todas as cargas desligadas após a falta. Devido a falta de exploração de outras metaheurísticas que utilizam a RNP como estrutura de dados, este trabalho visa realizar uma análise de desempenho comparando o AEMT com outras três meta-heurísticas, a Busca Tabu, Colônia de Abelhas e Estratégias evolutivas. A análise foi realizada em 3 SDEs com 84, 119 e 135 barras e foram simuladas 3 faltas em cada sistema.

  • CRISTIANO BRAGA DE OLIVEIRA
  • Controllable Graphene Electromagnetic Filters in the THz Range

  • Data: 19/02/2020
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  • Four graphene-based structures in the terahertz region are analyzed. The proposed structures are two electromagnetic filters formed by two coaxial graphene discs (or two rings) placed on opposite sides of a dielectric substrate and two magnetized graphene disc structures of radius r = 3µm (or radius R =µm) over a dielectric substrate. The proposed graphene and magnetized graphene structures were numerically modeled in the commercial HFSS software and analytically calculated using the Temporal Coupled-Mode Theory (TCMT). The results of numerical modeling and analytical calculations were compared using the transmission and reflection parameters, which showed a good agreement for both cases. For the structures of two electromagnetic filters other parameters were analyzed, such as the coupling between the two discs (or rings) and the dynamic control of the structure through the chemical potential variation µc in numerical modeling, where both showed the conciliation of simulations with the equations calculated by TCMT. The frequency response of the proposed structures is analyzed and discussed during this thesis.

  • JONATHAN MUNOZ TABORA
  • VOLTAGE HARMONICS EFFECTS ON THE TEMPERATURE AND PERFORMANCE OF IE2, IE3 & IE4 INDUCTION MOTOR CLASSES

  • Data: 19/02/2020
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  • The introduction of new technologies as well as the improvement of materials and processes has contributed to accelerate the growth in the efficiency of the electric induction motors (IM). Currently in the market it is possible to observe the operation of IM classes IE3 and IE4, as well as minor efficiencies, in the same way proposals for IM class IE5 are being developed. This work aims to show the impact of 2nd, 3rd, 5th and 7th order voltage harmonics on the temperature and performance of IE2, IE3 and IE4 induction motor classes, the latter being a hybrid motor of permanent magnets and squirrel cage (Line Start Permanent Magnet Motor, LSPMM's). The measurements were divided into two stages, first feeding each of the motors with undistorted voltages and then entering each of the harmonics individually and in combination in percentages of 2% until reaching 25%. The results showed that better efficiency classes present considerable improvements in relation to consumption, temperature and noise, however, also showing non-linear characteristics, as was the case with the LSPMM. It is also presented as the presence of individual harmonics in electric motors, results in the appearance of other harmonics, according to the percentage of distortion present. Finally, in order to predict the variation of temperature in relation to the percentage of different voltage harmonic distortion, statistical models were created resulting in good approximations for the temperature increase in the presence of voltage harmonics.

  • MAYRA MOURA MOREIRA
  • TRANSPORTE ELETRÔNICO VIA TUNELAMENTO EM SISTEMAS 1D E QUASI-1D COM ELETRODOS DE CARBONO

  • Data: 19/02/2020
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  •             Research in nanotechnology and nanoelectronics has aroused much interest in the sscientific context and, especially in recent decades, many efforts have been made to achieve the desired atomic and molecular level control over industrial processes such as manufacturing/design of molecular devices, miniaturization and/or flexibility of electronic equipment. Among the studies in these research fields stand out the carbon allotropes, such as carbon nanotubes (CNT), which are cylindrical structures obtained from the winding of a sheet of graphene and the carbyne wire formed by a linear chain of carbon atoms. The first junction consists of a sodium atom in the central region and carbyne wires as electrodes. The second is a quasi -one-dimensional (quasi-1D) junction and is composed of single-walled carbon nanotube (SWCNTs) closed at the tips as electrodes and again a sodium atom in the central region, being that in both systems (1D and quasi-1D) there is no effective bond between the central atom and the electrodes. To obtain the results we used the Density Functional Theory combined with the non-equilibrium Green’s functions formalism. The results obtained as: current-voltage curve, differential conductance, transmittance, state density and conduction channels show that the sodium atom significantly affects the electron transport properties and the comparison of the results obtained for the studied junctions with those of 1D and quasi-1D systems without the sodium atom in the central region can ratify such results. Therefore, the results show that the transport properties are directly affected by the molecular geometry of the systems and this fact may help in the manufacture of future molecular devices.

  • ALAN MARCEL FERNANDES DE SOUZA
  • USE OF MACHINE LEARNING TECHNIQUES AND DEEP LEARNING TO EXTRACT KNOWLEDGE AND MODELING OF THE PRIMARY ALUMINUM PRODUCTION PROCESS

  • Data: 14/02/2020
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  • The production of primary aluminum is carried out in several factories around the world. With the technological advances in the last decades, the high power of storage and data processing has allowed to solve problems that previously were considered extremely difficult. In this sense, a new paradigm emerges: industry 4.0, which is based on intelligent processes, integrated management, managed energy, high standards and quality. Many of the challenges that permeate industry 4.0 include machine learning techniques that facilitate data interpretation, enabling models to emulate the behavior of the production system with high accuracy, and to find hidden patterns in the huge data set. This PhD qualification proposes models based on machine-learning techniques (Artificial Neural Networks, various learning algorithms) and deep learning (Long-Term Memory Networks) to emulate the behavior of temperature, fluorided alumina and alumina concentration of a furnace reduction of primary aluminum from several inputs, using real data. In addition, the clustering of furnaces with similar behavior was carried out with the aim of increasing the accuracy of the mentioned models. The results indicate that the models based on Long-term Memory Networks are 20 to 25% more accurate than those based on Artificial Neural Networks. Additionally, it was verified that the clusters found do not significantly improve the model's accuracy. Further tests are still needed to confirm this proposition. It is important to mention that an extensive review of the literature was made through a systematic review that considered hundreds of scientific studies that approach modeling in the area of primary aluminum production.

  • RAMZ LUIZ FRAIHA LOPES
  • ABORDAGEM MULTIOBJETIVO OUTDOOR PARA POSICIONAMENTO DE ESTAÇÕES RÁDIO BASE E MODELO HÍBRIDO APLICADO À AVALIAÇÃO DA EXPOSIÇÃO HUMANA À RADIAÇÃO NÃO-IONIZANTE

  • Data: 07/02/2020
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  • This work presents a multiobjective tool for the planning of telecommunications services. This tool makes use of a discrete radio propagation modeling based on the K-Nearest Neighborhoods (KNN) classifier. The model takes into account different attributes of the environment considered in the calculation of propagation loss. In this case, the study was conducted in the facilities of the Federal University of Pará, representing a typically Amazonian environment. To develop the model, measurement campaigns were carried out in three different frequencies: 521 MHz, 2100 MHz, and 2600 MHz. The study of fading at these frequencies was carried out aiming at the generalization of possible frequencies for inclusion in the model. Tests for 700 MHz, 1800 MHz and 2400 MHz frequencies were performed to show the adequacy of the polynomial obtained in the generalization of the frequencies. The proposed model was applied on two scenarios to optimize the positioning of the base stations (ERB) under study. To calculate the optimal positioning of the ERBs, an importance criterion was adopted for each point of the considered scenario, based on a previous classification of the studied environment. The proposed model was applied in two scenarios, illustrating the results by a color map of the received power intensity at each point. Compared with the received power intensity data from performed measurement campaigns, the coverage estimates obtained with the proposed tool present significantly better results, illustrating a future scenario with a more efficient service in the studied territory.

  • PALINE ALVES SARAIVA
  • LOW COST PHOTOVOLTAIC SYSTEM IMPLEMENTATION IN CENTRALIZED RADIO ARCHITECTURE

  • Data: 31/01/2020
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  • Growing demand for higher data rates and better quality of Internet services has resulted in high investments in mobile network infrastructure by operators. In this context, Centralized Radio Architecture (CRA) is a promising solution that relies on centralizing, sharing, and better-allocating network resources, resulting in reduced deployment and operation costs when properly planned. While the benefits of CRA are numerous, this cost reduction can also be enhanced through the adoption of alternative energy sources. One of the options for this is the use of solar energy through photovoltaic systems, which adopts the sizing of its basic components, such as panels and inverters. However, one of the main barriers to the concrete use of such a system is its high cost of implementation, which cannot be overlooked. Therefore, the proper disposal of such equipment through optimization approaches, considering the energy demand of CRA , represents a challenge to be overcome. To this end, this paper proposes a strategy to minimize the cost of implementing a photovoltaic system by reducing the number of inverters, which is formulated as a Linear Integer Programming (ILP) problem, with the aim of further reducing costs related to CRA. From the results, it is evident that the optimization technique used implies the reduction of the Total Cost of Ownership (TCO) of the photovoltaic system, as well as the environmental sustainability through the reduction of carbon dioxide (CO₂) emissions in the atmosphere

  • CARMELA SOUZA OLIVEIRA
  • THE APPLICATION OF PHOTOVOLTAIC SYSTEMS IN 5G NETWORK TECHNOLOGY

  • Data: 31/01/2020
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  • With the deployment of the next generation of mobile networks, a significant increase in data consumption is estimated and, consequently, a substantial impact on energy consumption. In light of this scenario, it is interesting to think of alternative sources that can meet this energy demand and additionally act to mitigate greater environmental impacts. Based on this economicand, above all, environmental perspecive, this work proposes the use of a photovoltaics system as a strategy for the potentialization of energy consumtion in a less aggressive way to the environment. The experiments carried out evaluate the viability of the proposal from the implementation in two RAN (Radio Access Network) architectures that can be employed to the new generation (5G). The results demonstrate the financial viability in the installation of photovoltaic stru7ctures when compared to conventional sourcesof power generation.

  • PATRIK COELHO LOPES
  • Comparative Analysis of Different Cases of Plasmonic Nanoantennas in Reception Mode in Optical Nanocircuit Application.

  • Data: 30/01/2020
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  • In this work, a study is made for the different cases of optical nanoantennas. At nanoantennas considered are: dipole, dipole-loop, isolated loop and nanorod-loop, initially the transmission mode is analyzed to obtain parameters important for the study of nanoantennas, such as input impedance, coefficient of reflection, radiation efficiency, gain diagram. Then for analysis in the mode nanoantennas are excited by a linearly polarized plane wave, varying the direction of polarization. Where the power received by the load versus frequency is The nearby electric field is investigated for all four cases. The following is the application of an optical nanocircuit, which is composed of a circular nanoantenna of reception connected to a bifilar Optical Transmission Line (OTL) on one side, and a dipole on its terminal. In this case, a plane wave is the source and the near field are investigated, it is also made for analysis comparison mode optical nanocircuit separately for connected dipole and loop cases OTL with a load, the power received by the load versus frequency is calculated varying the polarization direction of the plane wave. And finally to get results closer to realistic applications an aperture probe with a beam is applied gaussian focus on nanocircuit. Numerical analyzes will be performed by the Finite Element Method (FEM).

  • DANIELE MOURA DE QUEIROZ
  • A BIG DATA ARCHITECTURE PROPOSAL FOR FAKE NEWS DETECTION

  • Data: 24/01/2020
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  • In last years, a large amount of information has been transmitted through the internet, especially in social media, providing ease in gaining knowledge on various topics, but making people susceptible to false information that can cause diverse damages. The spread of this false information has made it difficult to detect reliable news sources, increasing the need for computational tools that can help identify the reliability of digital content. In addition, estimates indicate that the amount of digital data produced per day is over one million gigabytes, of which 79% consists of unstructured data. This massive amount of data generated daily at high speed and in different types of formats such as text, images, videos and audios, makes analysing this data a big challenge. Thus, emerges the concept of Big Data, mainly defined by volume, variety and velocity. With the advent of big data technologies, it is possible to use a range of tools and techniques to efficiently store, process and analyse the massive volume of data in order to help investigate the credibility of shared news over the internet. In this work we discuss the importance of Big Data to avoid fake news, based on an appropriate conceptual and technological framework, and present a proposal of Big Data architecture for storage, processing and analysis of large data sets, aiming to assist in the investigation of truth of news. For this, experiments were performed using a mass of data containing different formats, ie structured and unstructured data, extracted from news sources and forming a corpus composed of false and true news. This mass of data was stored in a Hadoop cluster using the Hadoop Distributed File System (HDFS). The corpus was processed through the MapReduce programming model and the news was classified through the Mahout library. The preliminary results produced by the development of this study reveal an architecture capable of storing, processing and analyzing Big Data in the context of fighting fake news.

  • GABRIEL FELIPE DA SILVA BARROS
  • Non-reciprocal four-port graphene-based device with ring-elliptical ressonator for THz applications

  • Data: 21/01/2020
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  • A new type of four-ports circulator is suggestted and analyzed in this paper. The cross section of the componentes features a three layer structure consisting of graphene, silica and silicon. The plane of the circulator figure consists of a graphene circular resonator and four waveguides connected to it. The graphene resonator is normally magnetized in its plane by an external DC magnetic field. The physical principle of the devide is based on the dipole resonance of the magnetizes  graphene resonator. We investigated the influence of different parameters on the characteritics of the circulator. We use Coupled Mode Theory to prove the numerical calculations obtained through computer simulations, the device obtained approximately - 17 dB isolation and -3 dB insertion losses with 4.55 THz center frequency with 1 T polarization DC magnetic field, where the center frequency can be controlled by altering the fermi energy of graphene.

  • THIAGO LIMA DE OLIVEIRA
  • Four-por circulator with graphene-based disc resonator in the THz range

  • Data: 20/01/2020
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  • A new type of graphene-based four-port  circulator for the terahertz frequency range is proposed and analyzed in this paper. Consisting of two parallel waveguides laterally coupled to a disc-shaped magnetized resonator. The cross section of the components features a three layer structure consisting of graphene, silicon dioxide and silicon. The graphene resonator is normally magnetized in its plane by an external DC magnetic field. The physical principle of the device is based on the dipole resonance of the magnetized graphene resonator. The influene of different parameters on the characteristics of the circulator was investigated. Numerical simulations demonstrate - 15 dB isolation, insertion losses arouund -2.5 dB and 5.7% bandwidth with the center frequency is 5.03 THz. The DC bias magnetic field is 0.8 T. The center frequency of the circulator can be controlled by changing the fermi energy of graphene.

2019
Descrição
  • RAIMUNDO JOSE SANTOS MOTA
  • PROJETO E SÍNTESE DE SUPERFÍCIE SELETIVA DE FREQUÊNCIAS PARA O PADRÃO IEEE 802.15.3C VIA TÉCNICA DE OTIMIZAÇÃO HÍBRIDA MULTIOBJETIVO DE ALTA PRECISÃO

  • Data: 19/12/2019
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  • In this work is presented a hybrid bioinspired optimization technique that associates a General Regression Neural Network (GRNN) with the Multiobjective Bat Algorithm (MOBA), for the design and synthesis of the Frequency Selective Surfaces (FSS), aiming its application in data communication systems by diffusion of millimeter waves, specifically, in the IEEE 802.15.3c standard. The designed device consists of planar arrangements of metallizations (patches), diamond-shaped, arranged over a RO4003 substrate. The FSS proposed in this study presents an operation with ultra-wide band characteristics, its patch designed to cover the range of 40.0 GHz at 70.0 GHz, i.e., 30.0 GHz bandwidth and 60.0 GHz resonance. The upper and lower cutoff frequencies, referring to the transmission coefficient’s scattering matrix (dB), were obtained at the cutoff threshold at -10dB, to control the bandwidth of the device.

  • FLAVIA PESSOA MONTEIRO
  • USING TRUE RMS CURRENT MEASUREMENTS TO ESTIMATE HARMONIC IMPACTS OF MULTIPLE NONLINEAR LOADS IN ELECTRIC DISTRIBUTION GRIDS

  • Data: 19/12/2019
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  • Currently, for analyzing harmonic impacts on voltage at a point of interest, due to multiple nonlinear loads, the literature recommends carrying out simultaneous and synchronized measurement campaigns in all suspicious points with the use of high cost energy quality analyzers that are usually not available at the customers’ facilities and very often also not at the electric utilities. To overcome this drawback this paper proposes a method of assessing the harmonic impact due to multiple nonlinear loads on the total voltage harmonic distortion using only the load current true RMS values which are already available in all customers’ installations. The proposed methodology is based on Regression Tree technique using the Permutation Importance indicator which is validated in two case studies using two different electrical systems. The first case study is to ratify the use of Permutation Importance to measure the impact factor of each nonlinear load in a controlled scenario, the IEEE-13 bus test system, using ATP simulation (Alternative Transient Program). The second is to apply the methodology to a real system, an Advanced Measurement Infrastructure System (AMI) implanted on a campus of a Brazilian University, using low cost meters with only true RMS current measurements. The results achieved demonstrated the feasibility of applying the proposed methodology in real electric systems without the need for additional investments in high-cost energy quality analyzers.

  • TIAGO DOS SANTOS GARCIA
  • COMPARATIVE ANALYSIS OF WIRELESS OPTICAL NANOLINKS COMPOSED OF YAGI-UDA AND DIPOLE PLASMONIC NANOANTENNAS

  • Data: 17/12/2019
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  • In this work, we present a theoretical analysis of wireless optical nanolinks formed by plasmonic nanoantennas, where the antennas considered are Yagi-Uda and cylindrical nanodipoles made of Au. The numerical analysis is performed by the linear method of moments, where the transmission power and the near electric field are investigated and optimized for three nanolinks: Yagi-Uda/Yagi-Uda, Yagi-Uda/dipole and dipole/dipole. Some results are also obtained by the Finite Element Method. The results show that all these case can operate with good transmission power at different frequencies by adjusting the impedance matching in the transmitting antennas and the load impedance of the receiving antennas.

  • MARLON JOHN PINHEIRO SILVA
  • COMPARATIVE STUDY OF SWARM INTELLIGENCE TECHNIQUES IN ORDER REDUCTION OF LINEAR DYNAMIC SYSTEMS

  • Data: 17/12/2019
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  • Model order reduction has been a recurring problem and several techniques have emerged over the years, when, from the point of view of controller design, their elaboration and construction became inadequate, considering the high degree of redundancy, which large real physical systems may possess. In the field of deterministic mathematics, many works, already consecrated in the literature, have proposed to solve such problem. Recently, techniques involving metaheuristic methods in a predetermined search space using Swarm Intelligence (SI) have been used quite successfully and a new tool has been shown as a solution. Based on this context, this paper presents the understanding of the problem from the point of view of linear systems theory; conducting a comparative study between the Swarm Intelligences: Firefly Algorithm, PSO - Particle Swarm Optimization and SFLA - Shuffled Frog Leaping Algorithm.

  • FILIPE CAVALCANTI FERNANDES
  • PROBABILISTIC SELF-ORGANIZING MAP FOR AUTOMATIC PARTIAL DISCHARGE PATTERNS CLASSIFICATION IN HYDROGENERATORS

  • Data: 16/12/2019
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  • The most commonly used way to assess the stator isolation condition in hydrogenerators is monitoring partial discharges (DPs). In this work, we present a system for DP pattern classification using a new approach called Probabilistic Self-Organizing Map. Several literature techniques have been combined for preprocessing and pattern visualization. The methodology proposed obtains the separation boundaries on the map that maximize accuracy and automatically determine the probabilities for each type of Dp pattern.

  • FABRÍCIO PINHO DA LUZ
  • COMPARATIVE ANALYSIS OF DISPENSAL COMPENSATION PERFORMANCE IN OPTICAL FIBER NETWORKS

  • Data: 13/12/2019
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  • Este trabalho aborda o uso de métodos para tratamento da dispersão em fibras ópticas, mostrando a eficácia da utilização para um melhor resultado do Fator de qualidade (Q. Factor) e da taxa de erro de bit (Min. Ber) na transmissão de dados por redes de fibras ópticas. Desse modo, esta dissertação tem por objetivo fazer uma análise do desempenho de uma das técnicas de Pós-compensação em sistemas Multiplexação por Divisão de Comprimento de Onda Densa, baseado em redes ópticas passivas (DWDM-PON) com 16 canais e 100GHz de espaçamento para uma taxa de transmissão de dados de 10Gbps através do método de Pós-compensação de dispersão; propõe a utilização de técnicas de dispersão, a de Pós-compensação e a de dispersão Cromática na transmissão de dados por fibras ópticas com utilização de fibras compensadoras de dispersão (DCF) para um melhor resultado do fator de qualidade (Q-Factor) e da taxa de erro de bit (Min Ber). A metodologia aplicada teve base em levantamentos bibliográficos de trabalhos na mesma linha de pesquisa sobre métodos de tratamento dos efeitos não lineares, em especial o de dispersão em fibras ópticas; em seguida foi feita a modelagem da rede óptica no software OptiSytem da Optiwave Corporation para implementação das simulações dos métodos utilizados para tratamento da dispersão em fibras ópticas. Concluiu-se, a partir do estudo de três sistemas de compensação de dispersão, onde uma ligação DCF foi utilizada para esse fim, que os valores do fator Q e do BER foram comparados e analisados a uma taxa de transmissão de 10 Gb/s; que o fator Q e o OSNR para o sistema de compensação de simétrica (mista) eram os maiores, sendo considerado o melhor esquema de compensação de dispersão entre os três apresentados neste estudo.

  • RAIMUNDO CLAUDIO SOUZA GOMES
  • SMARTLVGRID - UMA PLATAFORMA APLICADA À CONVERGÊNCIA SMART GRID DE CIRCUITOS LEGADOS DE BAIXA TENSÃO

  • Data: 12/12/2019
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  • SMARTLVGRID - UMA PLATAFORMA APLICADA À CONVERGÊNCIA SMART GRID DE CIRCUITOS LEGADOS DE BAIXA TENSÃO

  • BRUNO RAMOS ZEMERO
  • METODOLOGIA PARA O PROJETO PRELIMINAR DE EDIFÍCIOS UTILIZANDO OTIMIZAÇÃO MULTIOBJETIVO BASEADA NA SIMULAÇÃO DE DESEMPENHO

  • Data: 11/12/2019
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  • O consumo de energia em edifícios tem um grande impacto energético e ambiental em todo o mundo. O projeto arquitetônico tem um grande potencial para resolver esse problema, porque o envelope do edifício exerce influência sobre o desempenho geral do sistema, mas essa é uma tarefa que envolve muitos objetivos e restrições. Nas últimas duas décadas, estudos de otimização aplicados à eficiência energética de edifícios ajudaram projetistas a escolher as melhores opções de projeto. No entanto, ainda há uma falta de abordagens de otimização aplicadas ao estágio inicial de projeto, que é o estágio mais influente para a eficiência energética do edifício ao longo de todo o seu ciclo de vida. Portanto, esta tese apresenta um modelo de otimização multiobjetivo para auxiliar os projetistas no projeto preliminar do edifício, por meio do algoritmo PAES (Pareto Archived Evolutionary Strategies) com o EnergyPlus Simulator acoplado, para avaliar as soluções. O processo de busca é executado por um matriz binária onde os componentes do matriz evoluem ao longo das gerações, juntamente com os outros componentes do edifício. A metodologia visa encontrar soluções ótimas com o menor custo construtivo associado à maior eficiência energética. No estudo de caso, foi possível simular o processo de utilização do modelo de otimização e analisar os resultados em relação a: Desempenho econômico, Desempenho ambiental, Desempenho energético, Desempenho térmico, Usabilidade e Precisão, provando que a ferramenta serve como suporte no projeto de construções. As soluções ótimas atingiram uma média de 50% de economia de energia em relação ao consumo típico, redução de 50% nas emissões operacionais de CO2 e retorno do investimento em menos de 3 anos nos quatro diferentes climas.

  • TIAGO DE SOUZA ARAUJO
  • DESIGN AND EVALUATION OF A SERIOUS ENGINE REHABILITATION GAME

  • Data: 10/12/2019
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  • The area of physical therapy rehabilitation always aims to improve the quality of life of patients, but the process of physical therapy can be considered tedious and tiring. Considering this problem, the Serious Games are presented as an aid tool in the recovery process of patients undergoing physical therapy treatments, which use virtual reality as a motivating element in the patient recovery process. The present work presents the design and evaluation process of a serious motor rehabilitation game which was evaluated by professionals and patients and presented relevant results in the criteria of ease of learning, efficiency, level of inconsistencies, user satisfaction and ease of memorization. through the use of the System Usability Scale (SUS). The Serious Exergame Utility - Questionnaire (SEU-Q) was also used to evaluate the perceived usefulness of the proposed Serious Game, which helped to identify important aspects related to the benefits of its use.

  • IURY DA SILVA BATALHA
  • LARGE SCALE ANALYSIS AND MODELING FOR FREQUENCIES 8, 9, 10 AND 11 GHz IN INDOOR ENVIRONMENTS

  • Data: 06/12/2019
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  • Recent research into radio propagation and large-scale channel modeling shows that frequencies can be used above 6 GHz for the new generation of mobile communications (5G). This thesis provides a detailed account of measurement campaigns that use directional horn antennas in co-polarization (V-V and H-H) and cross-polarization (V-H) in line-of-sight (LOS) and obstructed-line-of-sight (OLOS) situations between the transmitter and receptor; they were carried out in a corridor and computer laboratory located at the Federal University of Para (UFPA). The measurement data were used to adjust path loss prediction models of radio propagation, through the minimum mean square error (MMSE) method, for indoor environments in the frequencies of 8, 9, 10 and 11 GHz. The parameters for the models that were determined are as follows: path loss exponent (PLE), polarization exponent (co- and cross-polarization), effects of shadowing and path loss exponent for wall losses. Standard deviation means, standard deviation point by point, CDF and histogram are included as evaluation statistical metrics. The approximations with regard to the large-scale path loss models for frequencies of 8, 9, 10 and 11 GHz show convergence with the measured data, owing to the method employed for the optimization of the MMSE to determine the parameters of the model.

  • JORGE ANTONIO MORAES DE SOUZA
  • Method for Assessing Projects Of Settlement – MAPS

  • Data: 06/12/2019
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  • A Study on Changes in Land Use and Land Cover in Settlement Projects in the Amazon and their Impact on Native Forest Degradation.

  • JEAN CARLOS AROUCHE FREIRE
  • ANÁLISE DE DESEMPENHO DE ALGORITMOS PARA CLASSIFICAÇÃO DE SEQUÊNCIAS REPRESENTANDO FALTAS DO TIPO CURTO-CIRCUITO EM LINHAS DE TRANSMISSÃO DE ENERGIA ELÉTRICA.

  • Data: 05/12/2019
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  • Maintaining power quality in electrical power systems depends on addressing the major disturbances that may arise in their generation, transmission and distribution. Within this context, many studies have been developed aiming to detect and classify short circuit faults in electrical systems through the analysis of the electrical signal behavior. Transmission line fault classification systems can be divided into two types: online and post fault classification systems. In the post-missing scenario the signal sequences to be evaluated for classification have variable length (duration). In sequence classification it is possible to use conventional classifiers such as Artificial Neural Networks, Support Vector Machine, K-nearest neighboors and Random forest. In these cases, the classification process usually requires a sequence pre-processing or a front end stage that converts the raw data into sensitive parameters to feed the classifier, which may increase the computational cost of the classification system. An alternative to this problem isthe FBSC-Frame Based-Sequence Classification (FBSC) architecture. The problem with FBSC architecture is that it has many degrees of freedom in designing the model (front end plus classifier) and it should be evaluated using a complete dataset and rigorous methodology to avoid biased conclusions. Considering the importance of using efficient short-circuit fault classification methodologies and mainly with low computational cost, this paper presents the results of the KNN-DTW (K-Nearest Neighbor) algorithm analysis study associated with Dynamic similarity measurement. Time Warping (DTW) and HMM (Hidden Markov Model) algorithm for fault classification task. These two techniques allow the direct use of data without the need for frontends for signal pre-processing, as well as being able to handle multivariate and variable time series, such as signal sequences for the post-miss case. To develop the two proposed systems forclassification, simulated data of short-circuit faults from the UFPAFaults public database wereused. To compare results with methodologies already presented in the literature for the problem, the FBSC architecture was also evaluated for the same database. In the case of FBSC architecture, different front ends and classifiers were used. The comparative evaluation was performed from the measurement of error rate, computational cost and statistical test. The satisfactory results achieved demonstrate the applicability of the two techniques proposed for the short circuit fault classification problem.
  • JOSE DE SANTANA FIEL
  • CLASSIFICATION OF EPILEPTIC RESTING-STATE EEG SIGNALS BASED ON LINEAR CLASSIFIERS AND A CROSS-SPECTRUM FEATURE

  • Data: 04/12/2019
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  • Millions of Brazilians are affected by epilepsy. The diagnosis of patients with epilepsy is critical for initiating appropriate treatment. However, the diagnosis relies on visual inspection of neuronal electrical activity, recorded by electroencephalography (EEG), by trained neurophysiologists. Due to this, this process is time consuming and may require days of continuous EEG recording, which makes the diagnosis costly. Hence, the present dissertation proposes a framework for automatic identification of the EEG of epileptic subjects. The method can be applied to short-term records of resting-state EEG. The proposed system combines the use of a feature extracted from the power spectral density of EEG signals and machine learning algorithms. The attribute used is an estimate of functional connectivity between EEG pair of channels, named debiased weighted phase-lag index. The algorithms used for classification were linear discriminant analysis (LDA) and support vector machines (SVM). EEG signals were recorded during the interictal state, i.e., the period between seizures and had no epileptiform activity. In order to test the method proposed, records of 11 epileptic patients and 7 healthy subjects were used. The algorithms used reached their maximum performances, 100% accuracy and unit area under the receiver operating characteristic (AUROC), when a feature vector with 190 attributes was used as input. The results show the effectiveness of the proposed system, given the high segregation capacity of the groups.

  • FLAVIO MENDES DE BRITO
  • FRONTHAUL SIGNAL COMPRESSION TECNHIQUES EVALUTAION

  • Data: 27/11/2019
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  • The growing data demand of mobile networks has motivated the creation and evolution of architectures aiming to supply such transfer requirements. To meet these requirements, a number of challenges need to be met, including data transfer at the link between the Base Station Unit (BBU) and the Remote Radio Head (RRH). Known as fronthaul, this link requires high speed information transfer and one method to increase the rate is data compression. Therefore, this study aimed to evaluate different techniques used in fronthaul data compression. Initially, the efficiency of some quantizers such as the scalar quantizer (SQ), two-dimensional vector (VQ) and the Trellis Coded Quantization (TCQ) was verified. To increase compression, the Huffman encoder was used. Another analysis consisted of combining these quantizers with resampling, Block Scaling and Huffman coding. In both analyzes, it was found that the system using TCQ as quantizer obtained the best relationship between Error Vector Magnitude (EVM) and computational cost, offering an EVM lower than the scalar quantizer and a computational cost lower than the vector quantizer.

  • LUAN ASSIS GONCALVES
  • AN ANALYSIS THE USAGE OF MULTI-SCALE INFORMATION IN THE MAPPING OF PSNR TO PERCEPTUAL SCORE

  • Data: 18/11/2019
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  • The prediction of visual quality is crucial in image and video systems. Image quality metrics based on the mean square error prevail in the field, due to their mathematical straightforwardness, even though they do not correlate well with the visual human perception. Latest achievements in the area support that the use of convolutional neural networks (CNN) to assess perceptual visual quality is a clear trend. Results in other applications, like blur detection and de-raining, indicate the combination of information from different scales improves the CNN performance. However, to the best of our knowledge, the best way to embody multi-scale information in visual quality characterization is still an open issue. Thus, in this work, we investigate the influence of using multi-scale information to predict image distortion. Specifically, we propose a single-stream dense network that estimates a spatially-varying quality metric parameter from reference image. The proposed method achieved a reduction of 36.37% and 69.45% for the number of parameters and FLOPs, respectively, and its performance is compared with a competing state-of-the-art approach by using a public image database.

  • MARCELO SOUSA COSTA
  • IMPACTO TÉCNICO E ECONÔMICO DA INTEGRAÇÃO DE UMA GERAÇÃO DISTRIBUÍDA DE ALTA CAPACIDADE EM UM SISTEMA DE DISTRIBUIÇÃO COM REGULADORES DE TENSÃO EM CASCATA

  • Data: 14/11/2019
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  • This dissertation analyzes the technical and economical impact of a distributed generation in a distribution system composed of two circuits with two cascade step voltage regulator bank (SVRs) in each, being a case study in the circuits PR-09 and PR-11, both of them. 34.5 kV of the Paragominas Substation of the Centrais Elétricas do Pará – CELPA. This is the assessment of the technical and economic impact on consumers end energy distributors, resulting from the operation of a distributed generation (GD) of 12.5 MVA in the presence of two cascaded step voltage regulator bank (SVRs).

    Distribution networks with the presence of large distributed generation may subject SVR to scenarios of reversal of active power flow which, depending on the control modes "Active Bidirectional Flow to Opposite Limit" and "Reverse Flow by Cogeneration", result in abnormal situations, which may cause the voltage regulator to lose its regulating capacity, depending on the adjustment employed in the electronic control of the RT, as a consequence consumers may be subjected to severe undervoltage or overvoltage. This phenomenon, in which the voltage regulator loses the ability to control the desired bar voltage, is known as the runaway condition. In addition, large GDs, depending on their location in the distribution system, can cause critical overvoltages. Some actions can be taken to reduce or mitigate this effect, such as resetting the feeders, changing the Voltage Regulator setpoint, and modifying Distributed Generation mode of operation. The economic assessment was made for all operating scenarios studied, being important to show, in addition to the technical impact, the financial impact for customers and distributor.

  • VANDERSON GERALDO ARANHA DA SILVA
  • MANUTENÇÃO PREDITIVA EM SISTEMAS ELÉTRICOS DE POTÊNCIA UTILIZANDO REGISTROS DE DISPOSITIVOS ELETRÔNICOS INTELIGENTES (IEDs)

  • Data: 08/11/2019
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  • Today, electricity generation and transmission utilities are paid for the availability of their transmission functions (FTs) and no longer for what is generated and transmitted in the National Interconnected System (SIN). In this context, more and more efforts are made by generating and transmitting utilities so that untimely disconnections do not occur or be avoided. In addition to the loss of revenue when unplanned outages occur in the system, utilities are subjected to a rigid oversight process by regulators agents, such as the National System Operator and the National Electric Energy Agency. Investments in technology are allowing new directions for the operation and maintenance of power equipment, since high-capacity data-processing devices are enabling optimized predictive maintenance techniques based on the protection, control and monitoring of electrical quantities of the electrical system, as well as guaranteeing the speed and security of information. Intelligent Electronic Devices (IEDs) are multiprocessor systems with hardware and software that continuously work with electrical quantity measurements, protection, command, control, monitoring and have robust memories to record lists of events and waveforms of the analog signals in real time. In this work, real cases will be presented in which FTs shutdowns were avoided with the analysis of the lists of events and waveforms, which allows utilities to anticipate the problem, have the best decision making and significantly reduce its financial losses in the operation and maintenance of its electrical system.

  • VANESSA CASTRO REZENDE
  • METODOLOGIA PARA A CLASSIFICAÇÃO AUTOMÁTICA DE DOENÇAS EM PLANTAS UTILIZANDO REDES NEURAIS CONVOLUCIONAIS

  • Data: 07/11/2019
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  • As redes neurais convolucionais são uma das técnicas de aprendizado profundo que, devido ao avanço computacional dos últimos anos, alavancaram a área de visão computacional ao possibilitar ganhos substanciais nos mais variados problemas de classificação, principalmente aqueles que envolvem imagens digitais. Tendo em vista as vantagens na utilização dessas redes, diversas aplicações para a identificação automática de doenças de plantas foram desenvolvidas com o objetivo de fornecer uma base para o desenvolvimento de assistência especializada ou ferramentas de triagem automática, contribuindo para práticas agrícolas mais sustentáveis e maior segurança na produção de alimentos. Nesse contexto, este trabalho tem como objetivo propor uma metodologia para a classificação de múltiplas patologias referentes a diversas espécies de plantas tendo como insumo uma base de dados composta de imagens digitais de doenças em plantas. Inicialmente, essa metodologia envolveu etapas de tratamento das imagens da base de dados de doenças em plantas para possibilitar que estivessem aptas a serem entradas nos modelos de redes convolucionais selecionados (VGG16, RestNet101v1, ResNet101v2, ResNetXt50 e DenseNet169), assim como a geração de dez novas bases, a partir da base de referência, com dimensões de 32×32, 40×40, 48×48, 56×56 e 64×64, variando entre as 50 e 66 classes com maior representatividade, com o intuito de submeter os modelos a situações diversas. Após o treinamento dos modelos, um estudo comparativo foi conduzido com base em métricas de classificação amplamente utilizadas na área de aprendizagem profunda, como a acurácia no teste, f1-score e área sob a curva. A fim de atestar a significância dos resultados obtidos, foi realizado o teste estatístico nãoparamétrico de Friedman e dois procedimentos post-hoc, que demonstraram que a ResNetXt50 e a DenseNet169 obtiveram resultados superiores quando comparadas a VGG16 e as ResNets de 101 camadas. Em suma, a metodologia proposta neste estudo se mostrou eficiente no que tange a criação de um método para a identificação automática de patologias em plantas, podendo ser útil no que tange o diagnóstico precoce das doenças.

  • PAULO AUGUSTO SHERRING DA ROCHA JUNIOR
  • DESIGN AND IMPLEMENTATION OF A COMPUTER NUMERICAL CONTROL SYSTEM: SNAP CONSTRAINED SMOOTH TRAJECTORIES

  • Data: 31/10/2019
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  • Computer Numerical Control (CNC) is a technology made up of several blocks. Among these, lies the Trajectory Planning block, responsible for reference profile generation that are fed to position control loops. The need for Trajectory Planning arises from the mechanical constraints inherent to every plant to which CNC technology is applied. The machine's operational limits must be respected, in order to avoid several issues, such as: loss of precision, early wear of machine's parts and excessive vibration. This paper proposes a novel smooth real-time trajectory generation setup based on an embedded system platform. A real-time snap and jerk bounded control algorithm is proposed, to achieve continuous and smooth feed motion in traditional Numeric Control code file, dealing both with straight lines and arcs. A local motion blending algorithm, applicable to the proposed method, is also presented. The developed algorithm was deployed to a BeagleBone Black, an embedded System-on-Chip, single board computer and tested in a prototype router machine. A comparison between the proposed method against the seven segments and trapezoidal acceleration methods is presented, both in terms of performance and of real-time computing viability. Simulation and Experimental results demonstrate the effectiveness of the proposed method to generate velocity, acceleration, jerk and snap bounded three dimensional trajectories, reducing the RMS error in up to 8.2% and 22.38% when compared to the Seven Segments and to Trapezoidal Acceleration methods, respectively. Assessing the error area on straight angles, the proposed method produced error areas 24% and 80% smaller when compared to the Seven Segments and to Trapezoidal Acceleration methods, respectively.

  • JAHYRAHÃ LEAL DOS SANTOS CRUZ
  • STOCHASTIC AUGMENTATION WITH EXTENDED PREDICTION HORIZON BASED ON THE PID FOR A MULTIVARIABLE SYSTEM

  • Data: 25/10/2019
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  • This research aimed to investigate and design a control system based on a 10-step ahead Long Range Prediction Horizon Stochastic Augmentation (AEHPLA) procedure, which consists of combining the characteristics of a linear controller with a stochastic predictive controller, resulting in a more robust control system with predictive, linear and stochastic characteristics. For the application of the Stochastic Augmentation, the control system chosen was the digital PID controller, which results in an augmented prediction horizon controller, which will be compared to the digital PID controller. Both controllers were tested, by simulation, in a process that represents the dynamics of a helicopter, which is called 2DOF Helicopter (H2DOF), manufactured by Quanser. H2DOF is a multivariable system that has been decentralized by state space transformation to transfer function, generating two SISO systems, one for pitch angle and one for yaw angle, so that in decentralization it was considered that the influence of coupling is modeled as an internal disturbance of the system. The advantage of this technique is that it reduces the complexity of the multivariable system through the simplified control algorithms. In addition, decentralization requires pairing the best input with the best output, which is performed using the Relative Gain Array (RGA) method. For the purpose of proving the efficiency of the AEHPLA based control, simulation tests were performed in the Matlab programming environment: output load disturbance, input load disturbance, Gaussian perturbation, control effort weighting parameter variation and step type reference change. All tests were evaluated using performance and robustness indices. In all tests the AEHPLA-based control system obtained the best result compared to the PID controller.

  • PEDRO FERREIRA TORRES
  • DEVELOPMENT AND MODELING OF A LOW VOLTAGE DISTRIBUTION NANOGRID WITH DISTRIBUTED GENERATION SYSTEMS

  • Data: 23/10/2019
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  • The concept of direct current distribution minigrids has been gaining ground in academia and industry regarding the development of distribution grid applications with high penetration of distributed energy sources and storage systems. The adoption of a direct current distribution system facilitates the integration of sources such as photovoltaic and wind generation and storage systems such as batteries, as these technologies operate intrinsically in direct current. In this sense, this work presents the development of a direct current distribution nanogrid installed in the laboratory of the Group of Studies and Development of Energy Alternatives (GEDAE), of the Universidade Federal do Pará. The developed grid is composed by three PV generation systems and storage in battery banks and three load banks, distributed over the 200 m grid in a ring topology, on a 24 Vdc bus. Two simulation methodologies were developed and are capable of reproducing the nanogrid’s operational behavior under static and dynamic conditions, allowing the evaluation of the grid performance over a day of operation. Tests are also presented with measurements at strategic points of the grid to evaluate the system behavior under specific operating conditions, being normal or under contingency. The results attest the nanogrid's ability to reliably meet the loads, as long as it respects the limitations of the implemented power generation and storage system. In addition, it was found that the characteristics related to the charge controller topology benefits the power quality for the developed grid size and topology.

  • LORENA DOS REIS MORAIS
  • Competitive Autoassociative Neural Networks for Electrical Appliance Identification for Non-intrusive Load Monitoring

  • Data: 23/10/2019
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  • Residential environments are responsible for a large part of the consumption of electricity, and it is very relevant to help consumers in their decision making, aiming to achieve greater energy efficiency. For the consumer it is important to know about their monthly bill of energy consumption so that they can identify in these periods of their highest consumption as well as the most consumed equipment. Non-intrusive load monitoring (NILM) emerges exactly as a technique capable of assisting consumers with information about individual consumption of equipment, thus providing information that enables them to take initiatives to reduce their consumption and increase energy efficiency.

     In a NILM system four steps are key: the acquisition of aggregate data through the single sensor, the detection of equipment on / off events from the aggregate load, the extraction of disaggregated signal characteristics and the identification of equipment from the characteristics. extracted from the disaggregated signal.

     In the context of NILM systems, this work proposes the development of a new methodology for the recognition of electrical equipment in a residential environment using the Auto Associative Neural Networks Competition. For the development of the methodology three public databases containing a disaggregated load database of several equipments were used. The main idea of the proposed methodology is that, once validated, it can be applied to any database in the future, aiming at the development of new equipment recognition systems for new NILM systems. The good results achieved so far, with the methodology applied, recognizes 7 devices in each database, indicating that the proposed methodology may be able to perform the recognition task satisfactorily, which may contribute to the future creation. non-intrusive monitoring systems that meet market demands.

  • LUANA GONCALVES
  • ASSESSMENT OF COMPUTED TOMOGRAPHY IMAGES  WITH LOSSY CODING USING BAYESIAN NETWORKS

  • Data: 21/10/2019
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  • Currently, the medical images have a significant impact on the diagnosis of pathologies, consequently, the development of metrics for the evaluation of such images has been increasingin in order to  preserve or improve its original features when subjected to compression, enhancement and digital transmission operations. The complexity in order to performance analysis of a metric includes the correlation of metrics with the subjective data obtained experimentally and also the difficulty of obtaining such data. Therefore, development of new metrics and comparative evaluation of metrics applied to diagnostic images are relevant. In this work, a methodology for the acquisition of subjective data and visual quality assessment metrics Bayesian network based  developed specifically for the context of diagnostic images   are proposed.

  • JULIO CESAR REIS DA SILVA
  • TRANSPORTE ELETRÔNICO ENTRE NANOPARTÍCULAS METÁLICAS

     

  • Data: 11/10/2019
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  • Um dos grandes desafios da atualidade é a manipulação efetiva da eletrônica na escala nanométrica. Essa ideia foi iniciada por Aviram e Ratner em 1974 na criação de um diodo retificador unimolecular. A partir de então, investigações importantes têm se destacado em modelagem teórica de transporte eletrônico, com o intuito de se estudar a relação de dependência da estrutura da ponte molecular com as propriedades eletrônicas das ligações realizadas com os eletrodos, e desta forma construir um dispositivo eletrônico funcional. Assim, o trabalho de pesquisa realizou um estudo teórico das propriedades eletrônicas em junções de única molécula de Au, submetida em uma ponte molecular e pontos quânticos, através de análise das curvas características de Corrente-Tensão, Condutância diferencial-Tensão, Transmitância – Energia e Tensão, Densidade dos Estados do Dispositivo em função da Energia e Autocanais de Condução. Para tanto, usou-se a Teoria do Funcional da Densidade combinada a Função de Green de Não-Equilíbrio via pacotes de Softwares livres Siesta e Transiesta. Os resultados indicam a presença de muitos entrelaçamentos de regiões de probabilidades de transporte eletrônico, com certas diferenciações, gerando principalmente mudanças com estes que possuem pontos quânticos. Por fim, estes dispositivos eletrônicos de Au apresentaram vários indícios para outras pesquisas com outros tipos de materiais envolvidos nas mesmas ideias centrais de mudança de geometria com pontes moleculares e pontos quânticos para o controle de cargas e geração de novos fenômenos.


    Artigos Relecionados com a defesa da Dissertação:

    REIS-SILVA, J.C.; FERREIRA, D.F.S.; LEAL, J.F.P; DEL NERO, J.; Enhancing and optimizing electronic transport in biphenyl derivative single-molecule junctions attached to carbon nanotubes electrodes. Solid State Communications, 252, 46-50 (2017). DOI: 10.1016/j.ssc.2017.01.015

    S. M. Corrêa; D. F. S. Ferreira; M. R. S. Siqueira; J. C. Reis-Silva; J. F. P. Leal; C. A. B. da Silva Jr; J. Del Nero. Investigation of electronic transport under mechanical strain in a molecular junction composed of a polyyne bridge connected to SWCNT electrodes. Physical Chemistry Chemical Physics, 19 (33), 22078-22087 (2017). DOI:10.1039/C7CP03080K


  • ARILSON GALDINO DA SILVA
  • HYDROLOGIC FORECASTING MODEL USING ARTIFICIAL NEURAL NETWORKS: A CASE STUDY IN THE XINGU RIVER BASIN – ALTAMIRA-PA

  • Data: 10/10/2019
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  • Knowledge about the extent of riverbed overflow is extremely necessary for the determination of areas at risk. The City of Altamira-PA, located on the banks of the Xingu River, historically suffers from extreme events of floods that provoke floods, causing great damages to the population. Considering the problem, this paper presents a monthly level prediction system of the Xingu River based on neural networks perceptron of multiple layers. For the development of the system, rainfall data were used in the basin and sub-basins of the Xingu River, and SST information (Sea Surface Temperature) from 1979 to 2016. The satisfactory results demonstrate the great applicability the artificial neural networks to the problem.

  • FATIMA PRISCILA ARAUJO TEIXEIRA
  • COEXISTENCE ANALYSIS BETWEEN 5G SYSTEMS AND SERVICES FIXED IN MILLIMETER WAVE BAND

  • Data: 07/10/2019
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  • This works aims to analyze the impact of interference of a 5G system over a legacy 26 GHz fixed point-to-point system and, thus, obtain a minimum protection distance for these systems to operate without interfering with each other. To obtain these results, simulations were performed using the Monte Carlo method. The impact of 5G network co-channel interference on the fixed service was evaluated considering different parameters such as Fs antenna height, cell number, FS antenna gain and number of users. In the results obtained, the 7-cell tri-sectored network topology, combined with a 60 m FS height, had the greatest impact on the required protection distance, while other parameters such as gain and power had a moderate impact. These results imply that coexistence will be possible when all appropriate parameters are measured for each case in question. Another contribution of this dissertation is the availability of a coexistence model in the SEAMCAT simulator, which can help new scenarios for coexistence analysis.

  • DIORGE DE SOUZA LIMA
  • ELECTROMAGNETIC AND MECHANICAL ANALYSIS IN TRANSFORMERS UNDER INRUSH CURRENT AND SYMPATHETIC INRUSH

  • Data: 01/10/2019
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  • The power transformer is one of the most important equipment in the electric power system, allowing the feasibility of connecting the generating centers to the consumer centers, even over long distances. Reliable and continuous operation is of fundamental importance for service maintenance and is subject to various types of disturbances that can lead to failures. In this perspective, studies of the dynamic behavior of transformer windings through computer simulations have been widely used to safely and accurately evaluate their operation. Therefore, this paper presents the methodology for research on a 50 MVA power transformer using the finite element method for steady state and time domain analysis. Thus, the study was performed by means of couplings (electromagnetic-mechanical circuit). In the first analysis (circuit study), the ATPDraw software was used to obtain the behavior of the inrush current and solidarity energization during the transformer bank energization. Therefore, in the ANSYS MAXWELL software, electromagnetic studies were performed. For this, a real 3D model was used (taking into account the characteristics of the core lamination and windings, some of them in disc format). Thus, the results are presented as the behavior of magnetic induction and electromagnetic forces in the equipment windings. Finally, in the ANSYS STRUCTURAL software, structural (mechanical) studies were performed. Also, as before, a close-to-real 3D model was used, presenting as results the behavior of the total deformation in the winding, the mechanical stress suffered and the degree of safety during the occurrence of energization. The steady state studies were considered three operating conditions: nominal condition, solidarity energization and inrush current. For the nominal condition, the equipment's plate data was used, for the energizing condition (solidarity energization and inrush current) the largest amplitude obtained during the simulation was used. It is noteworthy that for the time domain analysis, only the condition of the inrush current was analyzed, both for the high computational cost required and for being the worst condition in the steady state analysis.

  • HUGO RODRIGUES DE BRITO
  • FORMULAÇÃO ANALÍTICA PARA ESTUDO DE REDES DE DISTRIBUIÇÃO ATIVAS CONSIDERANDO A PRESENÇA DE REGULADORES DE TENSÃO

  • Data: 26/09/2019
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  • Reguladores de tensão (RTs) localizados em alimentadores radiais de média tensão têm participação recorrente em diversas estratégias de mitigação dos impactos da interconexão de unidades de geração distribuída (GD). Entretanto, análises expeditas de parâmetros característicos de redes de distribuição ativas não costumam considerar o efeito das comutações de tape dos RTs em seus equacionamentos. Esta dissertação propõe uma formulação analítica para avaliar a influência desses dispositivos, baseada na adaptação matemática de equações clássicas da literatura. O aparato teórico deduzido diz respeito à variação de tensão ao longo da linha, ao requerimento de potência reativa, às perdas elétricas do sistema e à capacidade de hospedagem de GDs. A proposta é validada via estudos comparativos em um sistema-teste simples, bem como em um alimentador rural extenso de 34,5 kV que inclui dois RTs em conexão cascata e uma GD de elevada penetração em sua extremidade. O Open Distribution Simulator Software (OpenDSS) é utilizado para fins de modelagem e simulações de fluxo de carga convencional e de séries temporais. Os resultados evidenciam os méritos da formulação desenvolvida na correta estimação de parâmetros de redes de distribuição ativas com a presença de RTs, o que caracteriza uma melhoria em relação às ferramentas convencionais para estudos preliminares de integração de GDs.


  • THIAGO LIMA SARMENTO
  • COMPARISON OF SATELLITE TRACKING TECHNIQUES IN INCLINED ORBIT

  • Data: 26/09/2019
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  • This work implements satellite tracking techniques in inclined orbit and compares their performances with other techniques, describing operaton and implementng in a simulaton environment and in a real control system to generate the performance evaluaton of each one. One of the techniques investgated is reinforcement learning. Tracking satellites in inclined orbit is of paramount importance for telecommunicatons using this type of link, allowing automatc communicaton maintenance and extending the service life of satellite services in this situaton. Algorithms widely used in tracking, both in the literature and in commercial equipment, result in estmates or predictons of satellite positon rather than actual positon, and require a study of the specifc characteristcs of the region where the base staton is located. The complexity and investments in the tracking technique vary according to the commitment made in the antenna installaton and control systems, being necessary to compare the existng methods before their implementaton. The work develops the environment necessary to simulate satellite communicaton, from recepton to antenna movement, to analyze the performance of the technique in

  • VALERIA MONTEIRO DE SOUZA
  • PRÉ-DESPACHO ÓTIMO DA GERAÇÃO DISTRIBUÍDA PARA MELHORIA DA OPERAÇÃO DE REDES DE DISTRIBUIÇÃO COM PRESENÇA DE REGULADORES DE TENSÃO NO MODO BIDIRECIONAL

  • Data: 25/09/2019
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  • Os sistemas de energia elétrica têm sido significativamente alterados nos últimos anos devido à crescente integração de Geração Distribuída (GD) em suas redes. Entretanto, apesar das vantagens identificadas em se aumentar o uso de GDs, a modificação do caráter passivo dessas redes incorre em diversos impactos. Para que esses sistemas possam ter suas características de segurança, confiabilidade e robustez asseguradas, diversos estudos têm sido desenvolvidos para mitigar os problemas detectados provocados por esse tipo de geração e maximizar seus benefícios. Nesse contexto, é realizado, nesta dissertação, um estudo de integração de um Produtor Independente de Energia (PIE) em um alimentador rural extenso localizado no estado do Pará, o qual possui reguladores de tensão (RTs) em cascata e apresenta a possibilidade de manobra de rede com um alimentador vizinho. Com a conexão do PIE, os RTs desse alimentador podem ter seu fluxo de potência ativa invertido tanto pela potência injetada pela GD quanto pela reconfiguração topológica da rede, deixando-os sujeitos a perderem sua capacidade de controle com a ocorrência da condição de runaway. Sendo assim, os cenários operativos possíveis, com diferentes configurações dos RTs e considerando curvas de carga reais, foram analisados utilizando simulações realizadas no OpenDSS (Open Distribution Simulator Software). A partir da avaliação desses resultados, foi proposta uma estratégia de pré-despacho ótimo da GD do PIE visando não apenas evitar que a condição de runaway ocorra, como também contribuir para a garantia de níveis adequados de tensão e preservação da confiabilidade da rede na qual ele será integrado. Os testes de desempenho da estratégia confirmaram sua viabilidade como ferramenta de mitigação dos impactos causados por GDs de alta penetração em redes de distribuição reconfiguráveis que possuem RTs.

  • SUZANE ALFAIA DIAS
  • Uma estratégia para Alocação Eficiente de Recursos Móveis Utilizando Sistema Fuzzy para um Esquema de Planejamento e Provimento de QoS.

  • Data: 25/09/2019
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  • Com o crescimento dos dados móveis e as rápidas tendências de urbanização, haverá uma densidade extremamente alta de links de counicação sem fio nas cidades, sendo assim os usuários esperam um ambiente onde possam ter acesso à internet aos seus dispositivos a qualquer hora e local. Devido a problemas no CAPEX/OPEX, uma implantação de small cells não é uma estratégia ecnômica em cenários  de tráfego de dados intenso, desta forma, a utilização de UAVs para melhorar a cobertura e o desempenho da rede torna-se viável. A fim de Qualidade de Serviço da rede, foi proposto um sistema computacional para realizar tomada de decisão que recebe como entrada informações da rede como vazão, taxa de perda de pacote e atraso, e retorna a qualidade de rede para aquele tipo específico de aplicação. O sistema como um todo verifica a necessidade ou não do uso de Veículos Aérios Não Tripulados (UAVs) para melhorar a qualidade da rede e a cobertura da área de maior demanda. De outra forma, os UAVs permanecem na estação base. Através do método proposto houve melhorias na Qualidade de Serviço (QoS) da rede, permitindo uma perda de pacotes e no atraso, e um aumento na vazão.

  • ANA LAURA PINHEIRO RUIVO MONTEIRO
  • DESENVOLVIMENTO DE UMA FERRAMENTA COMPUTACIONAL PARA OTIMIZAÇÃO DE CÁLCULO LUMINOTÉCNICO DE INTERIORES BASEADO EM ALGORITMO GENÉTICO

  • Data: 17/09/2019
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  • There is a large quantity of lamps and luminaires that present characteristics, such as the amount of lumens and lifetime of lamps. Thus, there are several possible combinations of lamps and luminaires that can be employed as a solution to adapt the lighting of a given indoor environment. What will differentiate each solution will be the cost of investment and the time of financial return. This work presents the development of a tool that provides the user with the possibility to carry out lighting studies for any internal business environment, considering multiple scenarios and following the regulations set by the NBR ISO/CIE 8995-1:2013. Studies are carried out in an optimized method by running a genetic algorithm, which has as objective function minimization of time of financial return on investment of lamps and luminaires, which are necessary for the achievement of luminance area. For the development of the tool spreadsheets were associated with the Python programming language and the PyCharm as the development software. The lumens method was used for lighting sizing, the simple linear regression technique was used to estimate the rate of electrical power for a period of 10 years and Net Present Value alongside the discounted payback for analysis of financial return of the solutions generated by the tool. The developed tool was applied in four different scenarios in the Center of Excellence in Energy Efficiency of the Amazon (CEAMAZON) building. Valid solutions for all scenarios were found, that is, a quick payback, taking into consideration the initial investment, annual consumption and maintenance, if any. The best solutions were simulated by the software DIALux as an aid in the projection of the distribution of luminaires in environments. The aspects described in this work show the functionality and applicability of this tool, in order to support the user in the planning of lighting projects sizing, having achieved the established goal, showing functionality and effectiveness.

  • HUGO RIVIERE SILVA MORAES
  • Aplicação de Redes Neurais Profundas ao Diagnóstico de Faltas Incipientes em Transformadores

  • Data: 11/09/2019
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  • Este trabalho apresenta os resultados obtidos da pesquisa de aplicação de Redes Neurais Profundas para o problema de diagnóstico de faltas incipientes em transformadores baseado na análise dos gases dissolvidos em óleo (DGA). Dois modelos são propostos utilizando Redes Neurias Autocodificadoras Empilhadas e redes Neurais Convolucionais. Para o desenvolvimento do sistema foi utilizada a base de dados TC10 de equipamentos faltosos inspecionados em serviço e usada para a publicação da norma IEC 60599.

  • ALLAN RODRIGO ARRIFANO MANITO
  • Estimação das Parcelas de Contribuição de Cargas Não Lineares na Distorção Harmônica de Tensão de um Barramento de Interesse do Sistema Elétrico de Potência utilizando Rede Neural Artificial

  • Data: 06/09/2019
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  • Apresenta-se neste trabalho uma metodologia para estimar a contribuição de cargas não lineares na distorção de tensão de um barramento de interesse do sistema elétrico de potência. A estimação é realizada através da construção de um modelo com base em redes neurais artificiais (RNA), em que a entrada do modelo é constituída pelas correntes harmônicas provenientes das cargas não lineares que compõem o sistema em estudo, e a saída da RNA corresponde aos valores de tensão harmônica no barramento sob estudo, para a mesma frequência harmônica. O estudo é realizado para cada ordem harmônica individualmente e os dados necessários para a construção do modelo bem como para validação dos resultados são obtidos a partir de campanhas de medição sincronizadas e por meio de simulação computacional, através de estudos de fluxo de carga harmônico. A partir de comparações dos resultados de referência via simulação computacional com os resultados obtidos via modelo neural, é observado que a metodologia desenvolvida é capaz de classificar corretamente o grau de impacto de cargas não lineares na distorção de tensão em uma barra de interesse do sistema elétrico.

  • FABRICIO MENEZES MARES
  • EXPERIMENTAL EVALUATION OF DIFFERENT MATHEMATICAL MODELS APPLIED IN PERFORMANCE PREDICTION OF PHOTOVOLTAIC GENERATORS

  • Data: 04/09/2019
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  • Among the devices that guarantee the generation of electricity through the photovoltaic conversion process the module is the basic (elemental) unit of a photovoltaic system. The literature review revealed that exists “countless” mathematical models used to predict the performance of modules. However, in general, they can be classified into two categories: power models and models based on the equivalent photovoltaics cell/module circuits. Therefore, in this work 14 models were selected, being 11 of power, 2 based on equivalent circuits and 1 which is the composition of both, but all with the objective of estimating the maximum power (Pmp), which reflects the desired operating point on a given system. The evaluation process of the selected models was made from two statistical approaches: the descriptive, also referred to as traditional; and the comparative, which seeks to relate the estimates versus the measured values and admitted as reference. For this, 4 different photovoltaic modules were used, but of the same technology (polycrystalline), experimentally measured using a monitoring system installed in the testing area of the Study Group and Development of Energy Alternatives (GEDAE / UFPa). Statistical evaluations made it possible to identify the most adherent models, both in terms of precision and accuracy. However, it is important to emphasize that this is not enough to determine a single best model, because depending on the application objectives, it may be that the effort is a determining factor, or even more important than its accuracy. Thus, besides the statistical evaluations, at the end of this work an ordinal classification of the models is presented, considering a compromise relationship established between precision, accuracy and effort.

  • RODRIGO RODRIGUES PAIVA
  • SUPERFÍCIE SELETIVA DE FREQUÊNCIAS INTELIGENTE BASEADA EM GRAFENO

  • Data: 02/09/2019
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  • Neste trabalho, desenvolve-se uma formulação baseada no método diferenças finitas no domínio do tempo e na técnica exponencial matriz para modelagem de folhas de grafeno. Aplica-se a referida formulação para modelar superfícies seletivas de frequências (FSS) propostas neste trabalho, cuja célula unitária possui dois elementos de grafeno. A partir da mudança dos valores de potencial químico destes elementos, a estrutura pode operar com bandas de rejeição única ou dupla, reconfiguráveis. Propõe-se, portanto, uma FSS inteligente.

  • VICTOR HENRIQUE RODRIGUES CARDOSO
  • Optical Curvature Sensor Based on Core Diameter Mismatch Technique Applied for Flow Measurement

  • Data: 02/09/2019
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  • Recent advances and cost savings in optical devices have spurred a high interest in sensors based on fiber optics applied to measure physical and mechanical parameters. Several reseraches have demonstrated the great advantages of optical sensors such as low cost, compatibility, immunity to eletromagnetic interference, applicability and its versatility as temperature sensors, vibration, magnetic field, curvature, among others compared to convencional sensors. Wide versatility of optical sensors enable curvature measurement with wide aoolicability as fluid flow sensor and Health Structural Monitoring monitoring (SHM).

    This work aims to study the propagation of optical power in the structure based on coer diameter mismath technique (CDM), Singlemode-Multimode-Singlemode-Multimode-Singlemode (SMSMS), with curvature aiming at application as a low cost alternative, easy fabrication and acceptable sensitivity for flow measurement in pipes. The two multimode sections present in the sensor act as a coupler and re-coupler of core and cladding modes, and the singlemode section, in te middle, acts as a sensing element. The sctructure was analyzed by experimental measurements and numerical simulations. Experimental analyzes were performed for curvature meaurement and for flow measurement. In both the sensor generates interference patterns when it is bent. Numerical modeling was performed using the finite difference beam propagation method using software BeamProp 9.0 from the company Rsoft TM. Results demonstrate that aplicability as curvature sensors and flow measurement is feasible.

  • VICTORIA YUKIE MATSUNAGA DE OLIVEIRA
  • Optimal allocation of distributed generation in distribution networks using hybrid algorithm based on Cuckoo Search and Genetic Algorithm

  • Data: 02/09/2019
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  • This thesis presents a novel Cuckoo Search (CS) algorithm called Cuckoo-GRN (Cuckoo
    Search with Genetically Replaced Nests), which incorporates the benefits of genetic algorithm (GA) into the CS algorithm. The proposed method handles the abandoned nests from CS more efficiently by genetically replacing them, significantly improving the performance of the algorithm by establishing optimal balance between diversification and intensification. The algorithm is used for the optimal location and size of distributed generation units in a distribution system, in order to minimise active power losses while improving system voltage stability and voltage profile. The allocation of single and multiple distribution generation units is considered. The proposed algorithm is extensively tested in mathematical benchmark functions as well as in the 33-bus and 119-bus distribution systems. Simulation results show that Cuckoo-GRN can lead to a substantial performance improvement over the original CS algorithm and others techniques currently known in literature, regarding not only the convergence but also the solution accuracy.
  • ERICK MELO ROCHA
  • Investigation of Strategies for Detection and Diagnosis of Faults in Industrial Systems Based on Identification of Closed Loop Systems

  • Data: 30/08/2019
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  • This work investigates and proposes methodologies for detecting faults in industrial plants equipped with control systems operating in closed loop. The feedback control reduces the sensitivity of the closed-loop system to plant variations. Thus, the detection of faults in systems operating in closed loop is challenging due to. In this work, we propose the use of a tool to estimate the open mesh transfer function from closed loop data, in order to estimate parametric models for fault investigation. The technique investigated is an adaptation of the Two-Stage Method, which unfolds the process of closed-loop identification in two sequential stages of open-loop identification. In the first step, an approximation of the complementary sensitivity function for the closed loop system is identified. Subsequently, an approximation of the sensitivity function is estimated from the estimates obtained for the complementary sensitivity function. By using parametric identification techniques, an estimate of the uncorrelated noise input signal is obtained. This allows to obtain a reasonably accurate model of the open-loop plant. Results of computer studies are presented and discussed in order to highlight the strengths and weaknesses of the proposed strategy.

  • KAYT NAZARE DO VALE MATOS
  • Contribuição do Controle Secundário de Tensão Aplicado a um Parque Eólico Composto de Aerogeradores DFIG à Estabilidade de Tensão de Longo-Prazo

  • Data: 30/08/2019
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  • Esta tese investiga o uso do controle secundário de tensão (CST) em um parque eólico composto de geradores de indução duplamente alimentados (DFIG) e seus efeito na estabilidade de tensão de longo-prazo. Primeiramente, o desempenho do CST aplicado ao parque eólico é comparado com o caso em que somente é utilizado o controle primário de tensão (CPT). Uma análise detalhada é conduzida através de simulações no domínio do tempo, considerando regimes de velocidade de vento alta e baixa, limites variáveis de controles dos aerogeradores, cargas estática e dinâmica, bem como o modelo dinâmico do limitador de sobre corrente (OEL) e do comutador de tap sob carga (OLTC). Baseando-se nos resultados, o uso do CST em um parque eólico composto de aerogeradores DFIG pode postergar o colapso de tensão do sistema de potência. Além disso, uma situação adversa foi obtida mostrando que o CST pode levar o conversor do lado da rede (GSC) do DFIG a absorver uma quantidade significativa de potência reativa da rede elétrica e perder a capacidade de injetar reativos na rede. Para resolver este prolema, são propostas duas estratégias de controle auxiliares inseridas na malha de controle do GSC para impedir o fluxo inverso de reativos no GSC, bem como forçar o fornecimento de potência reativa para o sistema através do GSC. Os resultados indicam a eficácia das estratégias de controle auxiliares em postergar o colapso de tensão e aumentar a margem de estabilidade de tensão do sistema.

  • MARCUS VINICIUS DE OLIVEIRA DIAS
  • 5G MIMO AND LIDAR DATA FOR MACHINE LEARNING: MMWAVE BEAM-SELECTION USING DEEP LEARNING

  • Data: 29/08/2019
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  • Modern communication systems can exploit the increasing number of sensor data currently used in advanced equipment and reduce the overhead associated with link configuration. Also, the increasing complexity of networks suggests that machine learning (ML), such as deep neural networks, can effectively improve 5G technologies. The lack of large datasets make harder to investigate the application of deep learning in wireless communication. This work presents a simulation methodology (RayMobTime) that combines a vehicle traffic simulation (SUMO) with a ray-tracing simulator (Wireless InSite), to generate channels that represents realistic 5G scenarios, as well as the creation of LIDAR sensor data (Blensor). The created dataset is utilized to investigate beam-selection techniques on vehicle-to-infrastructure using millimeter waves on different architectures, such as distributed architecture (usage of the information of only a selected vehicle, and processing of data on the vehicle) and centralized architectures (usage of all present information provided by the sensors in a given moment, processing at the base station).

    The results indicate that deep convolutional neural networks can be utilized to select beams under a top-K classification framework. It also shows that a distributed LIDAR-based architecture provides robust performance irrespective of car penetration rate, outperforming other architectures, as well as can be used effectively to detect line-of-sight (LOS) with reasonable accuracy.

  • MARCOS VINICIUS SADALA BARRETO
  • Research and Development of a Framework for Testing Automatic Control Strategies for Performance Improvement in Apache Web Servers
  • Data: 29/08/2019
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  • In this work it is reported and discussed the results of a study aimingat to develop a computing environ mentesuitable to carry out feed a back control for performance improvement of Apache Web Server systems. The proposed approach provides response servisse to HTTP request sand makes interventions in the values of the available parameters in order to controlthe system in closed loop. The parameters for control actuation are Max Request Work sand Keep Alive Time out while the control led process variables are the computer memory resource and the percent of processor time use. The developed tools is not intrusive in the sense that it does not modify the source code of the web server orthe operating system. Results of experimental tests, by using system identification and PI control, show that performance improvement can be obtained during transient response.

  • DERCIO MANUEL MATE
  • COMPRESSÃO DE SINAIS EM SISTEMAS DE RÁDIO SOBRE FIBRA DIGITAL PARA REDES FRONTHAUL

  • Data: 23/08/2019
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  • A introdução de tecnologias como Carrier Aggregation (CA), Massive Multiple Input Multiple Output (MIMO) e Coordinated Multipoint (CoMP), visando melhorar a capacidade dos sistemas móveis de banda larga, aumenta o desafio para implantação do Mobile fronthaul devido à limitação da capacidade da infraestrutura, para suportar altas taxas de transmissão. Uma abordagem usada para lidar com a limitação da capacidade do frontahul é a compressão do sinal transmitido. Várias técnicas vêm sendo desenvolvidas para compressão do sinal no fronthaul e, a maioria dessas técnicas comprimem o sinal transmitido em banda base. Neste trabalho é desenvolvida uma técnica de compressão, para cenários específicos dos sistemas Rádio-sobre-Fibra digital configurados para transmissão do sinal em frequência intermediária. Esta técnica usa informações sobre o estado de canal de rádio (Channel state information), para controlar a compressão do sinal no fronthaul. Os resultados das simulações com a técnica desenvolvida demonstram a sua capacidade para reduzir o erro de quantização, permitindo a transmissão de sinais com modulação de 64 QAM, usando resoluções menores (até 4 bits por amostra) no quantizador. Portanto, taxas de compressão de 2:1, nos dados úteis, e um EVM próximo a zero são alcançados. Além disso, a técnica de compressão desenvolvida supera as técnicas μ-Law e A-Law, demonstrando tempos de execução dentro do limite de latência esperado nos sistemas 5G (1ms). Por fim, o desempenho da rede fronthaul é avaliado experimentalmente em um enlace ótico de 20 km, considerando cenários com e sem compressão do sinal.

  • WIRLAN GOMES LIMA
  • SYNTHESIS OF MULTILAYER FREQUENCY SELECTIVE SURFACES VIA BIOINSPIRED OPTIMIZATION

  • Data: 23/08/2019
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  • The analysis of electromagnetic devices via computer software usually demands high computational cost and high processing time. Sometimes, to meet certain design goals, finding the optimal structural parameters can take days or even weeks when done by trial and error and seeking accurate answers in highly complex structures. In this scenario, bioinspired computing tools (BIC) are strong allies in saving time, computational cost and, consequently, money. To enhance the power and efficiency of these tools, hybrid methods have been developed in which neural networks work together with optimization algorithms to achieve even more satisfactory results. In this context, this work presents the use of two multiobjective bioinspired optimization hybrid models for the design and synthesis of multilayer frequency selective surfaces (FSS). Initially, an electromagnetic investigation of the patch-like structures that will compose the multilayer FSS is made, which are a triangular loop and a solid diamond printed on a fiberglass substrate (FR-4), through computational simulations via CST® Micro software. Wave Studio, whose numerical technique is used for finite integrals (FIT). Three filters with different characteristics are designed: the first filter must have a resonant frequency of 10 GHz and a bandwidth of 8 GHz; the second filter must have lower and higher cutoff frequencies of 8 GHz and 12 GHz, respectively, acting as a reject band, fully reflecting the X band and; the third filter, having a dualband response, must have a higher cut-off frequency for the first band equal to 8 GHz and a lower cut-off frequency for the second band equal to 12 GHz, acting as a bandpass allowing transmission band X and reflecting part of the adjacent bands. Cutoff frequency and bandwidth values were obtained at a threshold of -10 dB. The synthesis process consists of tuning the objectives of the structures inserted in the cost function of the optimization algorithms. The modeling of the structures is performed by a general regression neural network (GRNN) and the optimization process is performed by the algorithms, being the multiobjective genetic algorithm (GA Multi) and multiobjective cuckoo search algorithm (MOCS). The results obtained by the hybrid methods are simulated by the commercial software CST® and Ansoft DesignerTM HFSS for model validation, since they use different numerical techniques, being the finite integral technique and the finite element method, respectively. Good agreement between the simulated results was observed, showing a reduction in the processing time of the structures, besides showing that the GRNN-AG Multi model stood out in relation to the GRNN-MOCS, being the most efficient for the optimization of multilayer FSS.

  • RAPHAEL BARROS TEIXEIRA
  • ANÁLISE DE SISTEMAS NÃO-LINEARES E SÍNTESE DE OPERADORES INVERSOS POR SÉRIES DE VOLTERRA DIAGONAIS

  • Data: 22/08/2019
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  • ANÁLISE DE SISTEMAS NÃO-LINEARES E SÍNTESE DE OPERADORES INVERSOS POR SÉRIES DE VOLTERRA DIAGONAIS

  • PEDRO DOS SANTOS BATISTA
  • Network slice admission using reinforcement learning and information-centric networking for mobile networks

  • Data: 21/08/2019
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  • The evolution of current 4G mobile network, the so-called 5G, is targeting an increased traffic load at a lower price, thus optimization of the delivery network plays an important role at this new network; another aspect of the evolution is that 5G has the ambition to be a highly customized network, which can be reliable enough to be used in industrial automation and cheap enough to be used for mobile broadband services. In this context, this thesis assesses two aspects of 5G, the first is to use information-centric networking (ICN) to improve the efficiency of multimedia delivery on mobile broadband services; and the second is the application of a reinforcement learning strategy as an enabler for the highly configurable network, which could pose a challenge to be understood and configured manually. We investigate ICN because it is one of the most promising research topics for the future internet. ICN aims at circumventing several issues of current internet protocol, among them, achieving a more efficient multimedia distribution. Given the significant growth rate of video transmission over mobile networks, it is sensible to consider how 4G/5G networks can leverage ICN. There is a substantial body of work considering ICN for fixed networks and also for the core of mobile networks. Less attention has been dedicated to ICN on the radio access network (RAN) or ICN-RAN, which has currently a user plane based on many connection-oriented protocols. To fully benefit from ICN, mobile networks must enable it on the RAN, not only on the core. This work details an ICN deployment on the RAN of the fourth and fifth generation of mobile networks and also presents a testbed that enables proofs of concept of this ICN-RAN using 4G. The results indicate, for example, that evolving ICN features can be tested with currently available tools, but the lack of hardware accelerators and optimized code limit the bit rate that can be achieved in real-time processing. In the context of network customization, the most prominent enablers are the so-called network slices. Slices can be understood as a part of the network that is customized to deliver certain services. The service requirements are imposed by the tenant, which acquire slices from an infrastructure provider. The 5G infrastructure provider must optimize the infrastructure resource utilization, usually admitting as many slices as possible, however, infrastructure resources are finite, and admitting all the slices could increase the probability of service level agreement violation. This thesis investigates the application of reinforcement learning agents that learn how to increase the infrastructure provider revenue by intelligently admitting network slices that bring the most revenue to the system. We present a neural networks-driven agent for network slice admission that learns the characteristics of the slices deployed by the tenants from their resource requirements profile and balances the benefits of slice admission against resource management and orchestration costs.

  • RODRIGO VEIGA DA SILVA
  • Regulação de tensão e frequencia em microredes ilhadas com veículos elétricos e geração distribuida utilizando otimização por enxame de partículas

  • Data: 16/08/2019
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  • Regulação de tensão e frequencia em microredes ilhadas com veículos elétricos e geração distribuida utilizando otimização por enxame de partículas

  • JOÃO VICTOR COSTA CARMONA
  • MODELING OF QUALITY LOSS OF H.264 VIDEOS CONSIDERING PSNR AND LOSS OF FRAMES

  • Data: 16/08/2019
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  • Multimedia applications have grown a lot in recent years, new applications like online games, teleconferencing, video on demand and IP telephony are just a few. However, there is a greater emphasis on the consumption of high-resolution video streaming over wireless communications networks, mainly due to the proliferation of mobile devices and a significant increase in access networks, which make it easier and information. Thus, as a consequence of this type of traffic, there is a need for investments in techniques and mechanisms that provide the end user with the desired quality and satisfaction with high resolution content. This work aims to perform video quality loss modeling, through performance analysis of various resolutions, specifically standards in HD and UHD, at 720p, 1080p and 2160p. In this sense, a strategy of probabilistic evaluation of loss of quality in wireless networks is performed, through a Naive Bayes, analyzing the interrelationship between the inferences generated by the group of target metrics. Thus, we analyze factors such as loss of PSNR, loss of frames I, P, B and Total (for the H.264 codec), due to packet loss.

  • JORGE EVERALDO DE OLIVEIRA
  • PHOTONIC BAND STRUCTURES IN MICROSTRIP ANTENNA WITH APPLICATIONS IN MICROWAVE AND TERAHERTZ

  • Data: 16/08/2019
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  • In this work we are analyzing the simulations of two microfita antennas. The first is an antenna using the ceramic material Bismuth Niobate (BiNbO4) doped with Vanadium Pentoxide (V2O5) on the substrate. The antenna patch was designed with indented power line to facilitate matching of impedances and the substrate with air holes was placed just below the patch to further decrease the losses. The second is a nanoanthene with Graphene Patch in the Terahertaz range and PBG (Photonic Band Gap) substrate with triangular mesh, and holes in the following height configurations h1, h2 and h3. At time h1 the substrate is fully drilled, while at heights h2 the holes will be made top to bottom of the substrate and the height h3 is the antenna with substrate drilled from the bottom up to the middle of the substrate. Therefore three antennas are created in these geometries using a triangular hole network. The arrangement of the holes in the dielectric substrate constitute the PBG structure, to increase the performance and efficiency of these antennas, extinguishing surface waves in the substrate of microfite antennas. The adopted geometry also improves antenna parameters such as efficiency and bandwidth. The commercial software HFSS and CST were used for the simulations of the antennas. After the numerical simulation steps the results of the parameters of these devices were obtained. The first antenna (periodic lattice with ceramic substrate) obtained a return loss of -36.21 dB, at a resonance frequency of 10.26 GHz, with a bandwidth of 2.18 GHz. In the simulations of the antennas of microfita with Patch of Grafeno the antenna h3 obtained double transmission band with chemical potential of graphene of 0,3 eV.

  • DAIMAM DARLAM ZIMMER
  • CONTROL AND NON-RECIPROCAL DEVICES IN THE SUB-THZ RANGE BASED ON TWO-DIMENSIONAL PHOTONIC CRYSTALS

  • Data: 05/07/2019
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  • The present work investigated the possibilities of new devices for integration in circuits operating in the sub terahertz range, these are based on photonic crystal technology, the developed components consist of dielectric cylinders of gallium arsenide (GaAs), arranged to form a square network filled by air. The devices are designed to operate in the sub-

    Terahertz frequency range. The first device is an key switch, Its operation being based on the orientation of a dipole mode on the magneto-optical resonator, that enters through one of the device ports, the geometry of this device consists of two waveguides forming an angle of 90º. The device has two states, on state where there is signal transmission (state on) and a state where signal blocking occurs (state off ), the transition between them being controlled from the variation of an external DC magnetic field H0 applied in the magneto-optical resonator. The switch has bandwidth of 8%, with insertion losses of -2 dB and insulation of -59 dB. The second devices have the function of insulators, devices that allow the propagation of the electromagnetic signal in one direction (forward) and blocks the signal propagating in the opposite direction (backward), its functionality and based on the principle of ferromagnetic resonance FMR, from the ferrite cylinder located in the center of the and subjected to the application of a constant external DC magnetic field H0 = 2700KA/m. The insulator presented has its waveguides aligned and connected to a resonant cavity composed of two stubs and the ferrite cylinder is located in the region of junction between the cavity and the waveguides. Reflections inside the resonant cavity of the device, combined with the incident signal, originate inside the magnetized ferrite cylinder a field distribution that resembles that of electromagnetic vortex. The numerical calculations performed show that in the range 0.105–0.109 THz, the device exhibits insertion losses of less than -1 dB and insulation -22 dB. Featuring bandwidth of 0.8% GHz for operation around center frequency 0.1066 THz. The third device is a power divider presenting its waveguides forming a T, with the differential of having a calcogeneto Ge2Sb2Te5 resonators which controls the device by varying the refractive index. An electromagnetic signal excites within the resonator a quadrupole mode to the amorphous state where transmission occurs and the dipole mode in the crystalline state causes the state of isolation of the device. The device has insertion loss of less than -3.4 dB and insulation of -50 dB, for operation in the range of 0.105-0.1085 THz.

  • VITORIA ALENCAR DE SOUZA
  • Signal Compression for fronthaul of CRAN  based Networks using an Evolutionary Algorithm

  • Data: 28/06/2019
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  • Centralized radio access networks are present as a potential alternative for next generation of wireless networks, because they are able to provide high data rates and allow the reduction of structural and operational costs in the network. The centralized architecture implements the concept of fronthaul, and enables the challenge to increase the capacity of data transmission in these links. In this way, the study of digital signal compression techniques presents itself as an alternative to reduce the cost of implementing centralized radio access networks.This work investigates the use of vector quantization methods in the compression of complex samples of baseband LTE signals. We propose the use of Genetic Algorithms in the training of sub-optimal codebooks for the vector quantization process in order to reduce the errors imposed in this process and consequent increase in fronthaul capacity. Results showed that the proposed compression algorithm allows reduction of fronthaul data rates associated with acceptable errors. It has been shown to be possible data rate compression factors of 3 to 12 times, with errors of approximately 1 % to 2%, respectively, proving the effectiveness of codebook training process in LTE signals present in the downlink of centralized radio access networks.

  • THIAGO MOTA SOARES
  • Three-Phase Harmonic State Estimation Including Transformer Saturation

  • Data: 28/06/2019
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  • This work presents the development of a three-phase harmonic state estimator for energy distribution systems that incorporates the effect of the saturation of transformers on the levels of harmonic distortion. This harmonic state estimator determines the modulus and phase angle of the nodal voltage and the injected current of a distribution network by means of the weighted least squares method, in which the resolution of the systems of normal equations is based on the decomposition into values singular At each iteration of the state estimation algorithm, the current injected into the bars connected to the distribution transformers of a distribution network is corrected by the addition of the magnetizing current in each harmonic order of interest. In addition, this work presents a methodology for creating pseudo-measurement, at fundamental frequency, which makes the system completely observable. This algorithm is able to satisfactorily estimate the harmonic state of a distribution network, since it has low estimation errors.

  • JOSE RUBEN SICCHAR VILCHEZ
  • SISTEMA INTELIGENTE DE BALANCEAMENTO DE FASES EM REDES DE BAIXA TENSÃO PARA UNIDADES CONSUMIDORAS MONOFÁSICAS
  • Data: 10/06/2019
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  • SISTEMA INTELIGENTE DE BALANCEAMENTO DE FASES EM REDES DE BAIXA TENSÃO PARA UNIDADES CONSUMIDORAS MONOFÁSICAS
  • FABRICIO ROSSY DE LIMA LOBATO
  • Resource Dynamic Provisioning In Space-Division Multiplexing Elastic Optical Networks Considering Impairments Physical Layer

  • Data: 07/06/2019
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  • In elastic optical networks (EON) employing weakly-coupled single-mode multi-core fibers (MCF), inter-core crosstalk (XT) can affect significantly the network performance, particularly when the number of cores and the path length increase. Hence, from the network perspective, the impairment-aware routing, spectrum and core assignment (IA-RSCA) problem is the most important concern of MCF-EON. In this thesis, we propose a dynamic provisioning methodology that solves independently the IA-RSCA problem taking impairments physical layer into account. To achieve the XT impact minimization, we decompose the IA-RSCA problem into two subproblems: the IA routing sub-problem and the IA spectrum and core assignment (IA-SCA) sub-problem. For the routing solution, a pre-computation method based on the k-shortest path is used, and a physical layer impairment verification phase is performed taking the required optical signal to noise ratio into account. For the IA-SCA sub-problem, the novel XT-aware greedy algorithm is proposed to minimize the XT impact on the MCF-EON performance as follows: for each new connection, the level of detected XT power of the new connection and interfering connections relative to the XT power threshold of each connection is minimized on the average over all those connections. This minimization is achieved by choosing the core and frequency slot of the new connection. In order to take the spectral overlapping extension of the new and interfering connections into account in the detected XT power, a novel frequency slot overlapping index is introduced. The performance of the proposed algorithm is evaluated through computer simulations. The results show that the total blocking probability and network average utilization achieved by the proposed algorithm are better than the ones obtained by core prioritization, random and first-fit strategies, for different scenarios of XT level and spectrum fragmentation.

  • SAMARA LEANDRO MATOS DA SILVA
  • Ultra wide band graphene circulators for THz region

  • Data: 07/06/2019
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  • Non-reciprocal components are an indispensable part of many microwave and optical systems. In the future, THz technology will also require these components. Existing publications show that the bandwidth of graphene based circulators in the THz region can be 10% to 20% with the use of very complicated structures. The suggested circulator consists of a graphene junction with a concave pattern and three waveguides symmetrically connected to it. Graphene is supported by SiO2/ Si layers. The circulating behavior is based on the non-symmetry of the graphene conductivity tensor that appears due to magnetization by a DC magnetic field normally applied to the plane of the graphene. We discuss the main parameters that define bandwidth and its influence on bandwidth. Circulators have record bandwidth that is twice as high as those published. We have shown that the circulator Y may have a bandwidth of 42% in the frequency range (2.75 THz to 4.2 T Hz), with insulation better than -15 dB and insertion losses greater than -2 dB, provided by the polarization DC magnetic field 1.5 T and the chemical potential of graphene 0.15 eV. For the two 4-port circulators we achieved a bandwidth of 44% for the same physical parameters.

  • INGRID ARIEL SILVA NASCIMENTO
  • Deep Learning Applied to Communications: Modulation Classification and Congestion Control.

  • Data: 31/05/2019
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  • The goal of this dissertation is to explore Deep Learning (DL) techniques applied to communications. DL has achieved success in areas such as computer vision and object detection and it is timely to investigate DL in communication problems. We tackle two different problems. More specifically, we explore in this dissertation how DL in conjunction with Reinforcement Learning (RL) can be employed to attend the strict requirements of the 5G system imposed to the Fronthaul network, as part of the C-RAN architecture. We compare Congestion Control using Deep Reinforcement Learning (DRL) algorithms with traditional methods, using as figures of merit throughput and latency. Besides congestion control, DL is also applied to Modulation Classification (MC), which is another communication problem. MC is important, for instance, in Cognitive Radio and military applications. In this dissertation, we discuss the benefits and drawbacks of using DL as an alternative for MC and show its efficiency in comparison to other machine learning methods applied to MC.

  • FERNANDO MANOEL CARVALHO DA SILVA SANTOS
  • Impact Evaluation of Wind Generation on the Short and Long-Term Operating Reserve using Time Series

  • Data: 30/05/2019
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  • It is a general consensus that increasing the integration of wind power in the total generation mix means operating and planning methodologies, as well as operational standards, must be revisited. The main reason is that the number of random variables and system complexities considerably increases with the addition of wind power. The main idea of this thesis is to discuss operating reserve issues from short- and long-term perspectives when a significant portion of the generation system is composed of wind power. By modeling and evaluating the generation and load uncertainties, the paper analyzes the complicated relationship between all these variables. Moreover, the thesis proposes a discussion of the probability distribution functions of the reserve needs in order to evaluate the impact on operating reserve capacity. It essentially means that load and wind power forecasting errors and forced unit generating outages will be represented, which characterize the main operating system obstacles associated with the performance of the operating reserve. In fact, under or over forecasting involving system load or system production can lead to different effects on system’s balance, mainly when the portion of wind power is significant in the total system generation. The experiments are conducted on the modified configuration of the IEEE-RTS 96 and on the planning configuration of the Portuguese Generation System.

  • ANDRÉ LUCAS PINHO FERNANDES
  • Technical Economic Assessment of Fronthaul and Backhaul Alternatives for Centralized Radio Architectures in 5G Indoor Scenarios

  • Data: 28/05/2019
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  • The fifth generation (5G) of mobile communication systems is the key element of a society that is becoming increasingly interconnected and digitalized. Future applications in social and industrial sectors will require from 5G networks higher standards of capacity, availability and reliability. Centralized access radio architectures (CRA) are emerging as a network transport alternative to meet the demands of the 5G, especially for indoor environment, where users spend most of their time. Such solution divides the transport network into two sections, backhaul and fronthaul, which can be subdivided into several levels of links. The fronthaul in CRAs is generally optical-metallic to take advantage of the high capacity of optical fibers and the acceptability of metallic cables in the information technology (IT) market. However, technologies such as G.(mg)fast digital subscriber line standard and phantom mode transmission can ensure high data rates to short lengths of metallic cables. The backhaul of CRAs should be optical in preference, in this way passive optical networks (PONs) become a good backhaul alternative in case of fronthaul exclusively in indoor environment, once they can provide large capacity at a reduced costs when compared to other fiber architectures. However, because of their point-to-multipoint nature, PONs may not meet the expected demands of availability and reliability for the 5G. From this context, in this work an technical and economic analysis for CRAs attending the indoor environment in the 5G context is performed, considering optical-metallic or full metallic fronthaul, as well as protected or unprotected PON backhaul. The analysis was carried out through a set of mathematical models and considered a dense urban environment, addressing both isolated buildings and an area containing ten thousand buildings. The results indicate that the best fronthaul alternative for a average building of a dense urban setting is the fully metallic one, provided that G.(mg)fast and phantom mode transmission are used. In addition, they also indicate that the use of protection schemes in a PON-based backhaul can meet the 5G availability requirements at an acceptable cost in a dense urban scenario

  • MARX MIGUEL MIRANDA DE FREITAS
  • Performance analysis of G.mgfast and fronthaul 5G access networks based on coaxial cables

  • Data: 27/05/2019
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  • With the expansion of data demand, current access technologies may soon become obsolete. It is estimated that from 2020 with the arrival of 5G technology and fifth generation fixed broadband, rates of at least 10 Gbps should be provided to end users. In addition, criteria such as low latency, flexibility and energy savings are key factors. In this work, the application of the coaxial cables in the frontaul of 5G networks and in Gigabit G.fast access networks also known as G.mgfast, in order to find high capacity and energy efficiency are evaluated. In this work, it will be shown that rates of up to 40 Gbps can be achieved in an RG06 coaxial cable with support for 140 antennas meeting 3GPP transmission criteria. In addition, we will see that data rates of up to 10 Gbps can be reached in RG59, RG06 and RG11 cables in G.mgfast networks, but bearing in mind that there is an optimum relationship between the rate and transmitted power. In addition, an optimization algorithm applied to coaxial cables as well as a type of analogue fronthaul are also proposed.

  • BRENDA VILAS BOAS
  • COMPRESSION OF CHANNEL STATE INFORMATION IN MULTIPLE INPUT MULTIPLE OUTPUT MOBILE SYSTEMS

  • Data: 24/05/2019
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  • The firsts trials of Firth Generation of wireless networks (5G) are taking place worldwide. A variety of use cases are envisaged, requiring flexible and scalable technologies to meet their key performance indicators. Massive MIMO is a 5G enabling technology that improves spectral efficiency. To exploit the advantages of MIMO, the transmitter needs to have information about the channel condition (CSI) of each User Equipments (UE). 5G is being standardized in Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) operational modes; hence, MIMO has to be feasible in both duplexing modes. As TDD operates downlink and uplink on the same frequency, it can rely on channel reciprocity to acquire the CSI needed to further design precoding and user scheduling, for instance. However, FDD cannot exploit channel reciprocity; therefore, massive MIMO in FDD mode is most challenging because the increasing number of antennas turns the feedback of CSI impractical. Hence, compressing CSI in MIMO FDD systems is of interest. Furthermore, the use of vast spectrum ranges, sub-6 GHz and mmWaves bands, leads to different channel characteristics. Moreover, the close packaging of antenna elements increases the spatial correlation among a MIMO array. Consequently, this correlation can be exploited to leverage compression of CSI. This dissertation presents an overview of CSI compression methods and proposes an heuristic transform coding method based on evaluation of transform basis and MIMO channel characteristics

  • MARCIO NIRLANDO GOMES LOPES
  • Modelling of the potential for hydropower generation: a contribution to energy planning in the Amazon region

  • Data: 08/05/2019
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  • This research presents an innovative methodology to predict the potential for hydropower generation using artificial intelligence techniques. A comparative analysis between the deep learning technique called Group Method of Data Handling (GMDH) and artificial neural networks with different optimization algorithms were applied for evaluation according to the case study for the future Jatobá plant, a plant in the Tapajós river basin, state of Pará, Brazil. The mean monthly rainfall in the subbasins of the Tapajós River was used as input to feed the developed models, which convert the volume of rain into energy. The non-physical models employed showed excellent skill and good efficiency to simulate this naturally complex and non-linear process, according to the statistical parameters of evaluation. Simulations were also carried out to evaluate the impact of climate change on hydropower generation for the future Jatobá power plant. The GMDH model presented a better performance among the others, highlighting its behavior during the dry season, critical period for the hydropower generation and that defines the steady energy of the enterprise. The success of this approach will reduce uncertainties and subsidize preliminary studies for plant implementation, as well as simulate scenarios to support planning, reduce costs and generate synthetic data for time series of power generation covering periods without observational field data.

  • EDSON KOITI KUDO YASOJIMA
  • A Modified Genetic Algorithm for Real Coded Problem Optimization

  • Data: 26/04/2019
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  • This work presents a modified Genetic Algorithm using a new crossover operator (ADX) and a novel statistic correlation mutation algorithm (CAM). Both ADX and CAM work with population information to improve existing individuals of the GA and increase the exploration potential via the correlation mutation. Solution-based methods offers good local improvement of already known solutions while lacking at exploring the whole search space, evolutionary algorithms provide better global search in exchange of exploitation power. Hybrid methods are widely used for constrained optimization problems due to increased global and local search capabilities. The modified GA improves results of constrained problems by balancing the exploitation and exploration potential of the algorithm. The conducted tests present average performance for various CEC’2015 benchmark problems, while offering good reliability and superior results on path planning problem for redundant manipulator and most of the constrained engineering design problems tested when compared with current works in the literature and classic optimization algorithms.

  • ALEXANDRE FARIAS BAIA
  • A Competitive Structure of Convolutional Autoencoder Networks for Arrhythmia Classification

  • Data: 17/04/2019
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  • This work presents the proposal of two automatic systems to aid in the detection of anomalies in heart beats and medical decision support. The systems were developed for the identification of rhythmic arrhythmia and morphological arrhythmias from signals obtained from an electrocardiogram (ECG). Both systems are based on a competitive structure of Convolutional Autoencoders (CAE), and each network was trained to reconstruct the signals presented at its entrance. For the case of the rhythmic classifier, the system was developed from the use of the ECG signals, without undergoing a feature extraction process, and for the case of the morphological classifier, the system was based on the QRS complex extracted from the ECG signal. For the development and testing of the systems, the database MIT-BIH Arrhythmia of ECG signals was used. An accuracy of 88.9% was achieved for the Rhythmic Classifier and 81.73% for the Morphological Classifier, in the case in which the evaluation basis is considered. The results obtained demonstrate the applicability of the proposed competitive structures to the arrhythmia classification problem.

  • AUREA MILENE TEIXEIRA BARBOSA DOS SANTOS
  • EDUCATIONAL DATA MINING: A STUDY ON SOCIOECONOMIC INDICATORS IN EDUCATION IN INEP DATABASE

  • Data: 09/04/2019
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  • The Educational Data Mining enables the discovery of factors that make it possible to improve educational proposals, as well as to predict student performance and factors that influence learning. In view of this, the present work uses the database provided by INEP, with the purpose of explaining better which socioeconomic variables influence the grades that the students obtained in the test of the Enem 2016, one of the exams of major importance and with an high quantity untapped data. The PCA technique was applied and Bayesian Networks were generated to analyze the performance. The results show that income, parental schooling and school type are strong influencing factors.

  • NILTON RODOLFO NASCIMENTO MELO RODRIGUES
  • Smart terahertz graphene antennas

  • Data: 05/04/2019
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  • In this work, two graphene antennas are proposed. The first antenna is a graphene device with dynamical control of radiation pattern. This device is formed by a graphene dipole with two coplanar graphene parasites. Working in the frequency range 1.94−2.13 THz, this antenna has four operation states that can be selected by setting specific chemical potentials by external electric field on the graphene elements. In state 1, a dipole-like radiation diagram is produced. States 2 and 3 are characterized by specific directional radiation patterns. By selecting the operation state 4, the antenna is switched off. When a silicon dioxide substrate with thickness of 1 micrometer is considered, chemical potentials are adjusted so that the device operates in 1.94−2.15 THz range, with negligible changes of its four radiation patterns with respect to the case without substrate. The second antenna consists of a loop graphene antenna with reconfigurable operation band. This antenna consists of a ring graphene element excited by a graphene-based emitter photomixer. By modifying the chemical potential of graphene, the device can operate at multiple frequencies in THz band. The maximum of the antenna total efficiency occurs near to its second resonance frequency, in which the antenna presents a dipolelike radiation pattern. The fractional bandwidth and the operation band of this device can be changed from 21.74% (2.05−2.55 THz) to 30.64% (2.57−3.5 THz). It is shown that the loop antenna, in its second resonance frequency, operates in a way that is compatible to the model of array of small dipoles.

  • CARLOS ALBERTO OLIVEIRA DE FREITAS
  • Cultural Memetic Algorithm for Optimization of Problems of Real Variables

  • Data: 29/03/2019
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  • The technology has made great strides in recent years, yet computing resources for certain applications need optimization so that the costs involved in solving some problems are not high. There is a very broad area for research into the development of efficient algorithms for multimodal optimization problems, but the cultural multimodal algorithms are not always evaluated by efficient statistical tests. The purpose of this work is to analyze the behavior of the Cultural Algorithms, with populations evolved by the Genetic Algorithm when the local search heuristics are used: Tabu Search, Beam Search, Hill Climbing and Simulated Annealing. In order to perform the analysis, a memetic algorithm was first developed by the hybridization of the cultural algorithm with the local search heuristics: Tabu Search, Beam Search, Hill Climbing and Simulated Annealing, being selected one at a time. Real-world problems usually have multimodal characteristics, so evaluations were performed using multimodal benchmark functions, which had their results evaluated by non-parametric tests. Also, the memetic algorithm was tested in real optimization problems with constraints in the engineering areas. In the evaluations carried out, were found better results than those in the scientific literature searched.

  • ALANA LIMA DE SOUSA
  • ESTIMATION OF DISTRIBUTED GENERATION HOST CAPACITY IN DISTRIBUTION NETWORKS WITH GENETIC ALGORITHMS

  • Data: 29/03/2019
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  • The use of distributed generation (DG) and distributed energy sources (DER) close to the consumer centers has been gaining prominence around the world. The high penetration level of DG will shift the operation paradigm of electric energy systems, affecting power quality delivered to consumers. The active power injection from DG can cause several consequences to distribution systems, being overvoltage issue the most impacting of them. The reverse power flow from the DG units can cause voltage rise issue on distribution networks and consequently the DG shutdown. During unity power factor (pf) operation of DG, the distribution operators control overvoltage by active power curtailment. In this scenario emerges the GD hosting capacity concept, which consists of estimating the maximum power injected by GD without compromising voltage quality of the distribution system. This dissertation estimates the DG hosting capacity on MV distribution systems using genetic algorithms, considering as main limiting factor the overvoltage issue. Performance tests were performed on IEEE 33-bus and IEEE 69-bus systems

  • WILLIAM MOREIRA DE ASSIS
  • Experimental Validation of Electrical Models of Residual Voltage Stress Test Arrays

  • Data: 22/03/2019
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  • This work proposes an electric model for residual stress tests in ZnO suppressors for standardized and non-standardized waveforms using models of para-rays already consolidated in the literature. The Proposed Model was validated from tests carried out at the UFPA High and Extra High Voltage Laboratory (LEAT), obtaining results of residual voltage and discharge current measurements. In the tests, the 30kVrms nominal voltage arrester subjected to discharge current with waveforms, ranging from 8μs to 5μs of wavefront time, and inductors were used available in the laboratory to change the values of front and tail of impulsive waveforms. In addition, simulations were performed in the ATP Draw software to evaluate the accuracy of the model for other types of waveform, which could not initially be performed in the laboratory. The model result was compared to the measurement results. The model proved to be satisfactory for all impulsive waveforms. The parameters of the model are easy to determine, and all necessary information for the lightning arrestor and pulse generator is contained in manufacturers' manuals and catalogs.

  • PAULO HENRIQUE GONCALVES BEZERRA
  • A Collaborative Routing Protocol for Video Streaming with Fog Computing in Vehicular Ad Hoc Networks.

  • Data: 22/03/2019
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  • Vehicular Ad hoc Networks (VANETs) play an important role in the efficiency of road traffic by improving safety and acting as a facilitator of services for passengers, drivers and public safety officers. Recent improvements in the routing protocols and topologies used in vehicular networks have contributed to improvements in scalability, reliability and the quality of the information-sharing experience. Vehicles can cooperate with each other to stream videos of accidents or disasters and provide visual information of the monitored area with great precision. This Ph.D thesis proposes a Collaborative Routing Protocol for Video streaming VANETs (CRPV) using the service of fog storage to minimize the sharing of content. The routing table is based on an indicator that is generated by combining the speed, location and recording angle parameters of each vehicle involved in vehicular collaboration to reduce the unnecessary exchange of video data in vehicle-to-vehicle communications. The results of the simulations show that the proposed model performs favorably when compared to other routing protocols with respect to the availability of end-to-end communication and Quality of Experience.


  • WATERLOO FERREIRA DA SILVA
  • ANÁLISE DOS IMPACTOS HARMÔNICOS NA QUALIDADE DA ENERGIA ELÉTRICA UTILIZANDO KDD-ESTUDO DE CASO NA UNIVERSIDADE FEDERAL DO PARÁ

  • Data: 18/03/2019
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  • ANÁLISE DOS IMPACTOS HARMÔNICOS NA QUALIDADE DA ENERGIA ELÉTRICA UTILIZANDO KDD-ESTUDO DE CASO NA UNIVERSIDADE FEDERAL DO PARÁ

  • THIAGO ANTONIO SIDONIO COQUEIRO
  • A Fuzzy Logic System for Vertical Handover and Maximizing Battery Lifetime in Heterogeneous Wireless Multimedia Networks

  • Data: 15/03/2019
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  • The applications that consume high bandwidth and energy consumption have been increasing considerably fast in mobile networks. However, the mobile devices do not offer support to battery capacity for the intensive / continuous use of such applications. In addition, mobile networks currently have a high degree of heterogeneity and comprise a wide variety of networks with different technologies, such as LTE, Wi-Fi and WiMAX. Therefore, it is necessary the tradeoff to ensure that QoE is provided to users in this scenario, as well as an energy efficiency strategy designed to extend the battery life of mobile devices. This thesis proposes an intelligent architecture based on fuzzy logic, capable of providing support to decision making to save the energy of mobile devices within an integrated LTE and Wi-Fi network. The simulated experiments show the benefits and feasibility of the proposed solution.

  • ANTONIO FERNANDO MARTINS CARDOSO
  •  

    ANALYSIS OF MODELS, SIMULATIONS AND PULSE TESTS IN A DISTRIBUTION TRANSFORMER.

  • Data: 12/03/2019
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  • In this dissertation the transient phenomena present in the electric power systems were studied, specifically analyzing voltage surges derived from the incidence of atmospheric discharges in transmission and distribution lines and how these affect one of the most important components of the electrical network, the transformer. A high voltage test was performed on a three-phase distribution transformer with 30kVA, primary power connected at triangle 13.8kV, secondary at star 220 / 127V applying full voltage pulses of 100kV and reduced voltage pulses of 50kV at the primary of the transformer. The waveform provided in the international standards was adopted to the characterization of an atmospheric discharge. Comparing the results obtained with the tests, with models presented by the same distribution transformer, in the software Alternative Transients Program (ATP), we observed the consistency and precision of these models adopted here for the representation of transformers in studies of high voltage and frequency, thus validating them.

  • HUGO MENEZES BARRA
  • DESIGN OF ROBUST CONTROLLERS AND CANCELLATION OF POLES TO RECOVER FAULTS IN A HIGH VOLTAGE SYSTEM.

  • Data: 28/02/2019
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  • This work presents and discusses the implementation of classic and robust pole cancellation controllers to recover the current after the application of shorting type faults, besides other analyzes are made, such as the impact that the short causes in the voltage Vabc , current Iabc and as the passive filter developed to mitigate the higher energy harmonics of this system (which are of the 5th and 7th order) act on this voltage and current respectively.
    The system chosen is based on the Cigrée Benchmark (Sood, 2004) and represents an important industrial system, which is the furnace for the casting of aluminum ingots, used in multinational companies, among them, Hydro Alunorte. to be a contribution to industrial companies, especially in our region.
    The developed controllers first used the classic IP pole-cancellation methodology and the other one aiming for a greater reliability margin in its use, since it is designed to be a robust controller and that responds to the uncertainties of the plant that are caused by the set of elements of electronics, such as inductors and resistors.
    Therefore, the plant was linearized and from the transfer function of the interval plant, a robust controller was developed using the numerical methods of Kharitonov and Bhattacharyya, which relate the set of interval polynomials and their transfer functions to the formation of a polyhedron where one can choose the controller from the gain and phase margins established by the designer, thus increasing the reliability of the designed controller.
    The results obtained in the simulation tests showed the good performance of the designed controller, with a fast recovery of the current, after the applied fault. This allowed for the important result of providing a safe operation of the industrial plant, where without the use of the controller could lead to problems such as accidents, production stoppage and loss of stability.

  • WAGNER ORMANES PALHETA CASTRO
  • Nonreciprocal graphene-based devices in the THz region

  • Data: 28/02/2019
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  • Four new types of nonreciprocal graphene-based devices operating in the Terahertz region are suggested and theoretically analyzed in this work. They are two three-port circulators with Y and W geometries and two power dividers with different geometries. The cross section of the components has a three-layer structure, composed of graphene, silica and silicon. The planes of the figures of these components consist of a circular resonator of graphene and waveguides connected to it. The graphene resonator is magnetized normally of its plane by an external DC magnetic field, and the physical principle of operation of the devices is based on the dipole resonance of the magnetized graphene resonator. Using the Magnetic Group Theory, we analyze the scattering matrices of the symmetrical components of the devices. In addition, for the analysis of the circulators, the Analytical Temporal Coupled Mode Theory was also used. Numerical simulations were performed by a full wave computational program and the calculations demonstrate isolation levels better than -15 dB for both the circulators and the dividers. The Y-circulator has insertion losses around - 2.6 dB, bandwidth of 7.4% at the center frequency of 5.38 THz, whereas the circulator W showed insertion losses of - 2 dB, bandwidth of 4.5% at the center frequency of 7.5 THz. The DC bending magnetic field in the two cases was 0.45 T and 0.56 T, respectively. The power dividers have shown to posses the division of the signal between the two output ports of -5 dB with in the frequency band of 6% and the magnetic filed of 0,8 T. The influence of geometric and physical parameters on the characteristics of the circulators is discussed. The frequency bands of the devices can be controlled dynamically by changing bias voltage applied between the graphene layer and the substrate.

  • WALDEIR DE BRITO MONTEIRO
  • Evaluation Of A Crosstalk Estimation Method in C-RAN networks With Cooper Fronthaul using Linear Regression and Neural Network.

  • Data: 26/02/2019
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  • The implementation of the 5G standard will make the current mobile network architectures evolve towards C-RAN configurations, which are characterized by concentrating processing on a base station, from where the signal is distributed to remote antennas. To maintain uniform coverage, these systems rely on a dense network of low-power antennas scattered throughout buildings. This approach increases the complexity of the network’s Multi Input Multi Output (MIMO) system, which may hamper certain measurements involving equipment at both ends of the link. This work presents a method for the estimation of Far End Crosstalk (FEXT) and Insetion Loss (IL) using only one end of the link in order to avoid synchronization problems present in complex MIMO systems. Compared to other methods with similar proposals, the presented technique combines a simpler approach to a lesser degree of dependence on dual loop measurements, besides complementing techniques that can accomplish these measurements, but in a restricted range of frequencies.

  • ANDREY VIANA PIRES
  • ELECTROMAGNETIC SCATTERING ON GRAPHENE USING IMPEDANCE TRANSFORMS

  • Data: 22/02/2019
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  • Graphene is a two-dimensional material with good electrical properties that make possible new telecommunications applications in telecommunications on the terahertz range. This work presents an alternative analysis of the scattering problem in a graphene sheet using the impedance transform. The Green functions, electromagnetic fields and properties of the plasmonic surface wave on the graphene are demonstrated. The numerical results show the spatial field distributions and spectral analysis of the plasmonic wave as a function of media properties, frequency and chemical potential. The results show that the impedance transform is adequate for scattering analysis in graphene sheets because it uses the natural autofunctions of the problem.

  • WELLINGTON VIANA LOBATO JÚNIOR
  • Platoon-based Driving Protocol for Multimedia Transmission over VANET

  • Data: 22/02/2019
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  • Vehicular Ad-hoc NETworks (VANETs) allow users, services, and vehicles to share information, and will change our life experience with new autonomous driving applications. Multimedia will be one of the core services in VANETs, and are becoming a reality in smart environments, ranging from safety and security traffic warnings to live entertainment and advertisement videos. However, VANETs have a dynamic network topology with short contact time, which leads to communication flaws and delays, increasing packet loss and decreasing the Quality of Experience (QoE) of transmitted videos. To cope with this, neighbor vehicles moving on the same direction and wishing to cooperate should form a platoon, where platoon members act as a relay node to forward video packets in autonomous VANETs. This master’s dissertation introduces a Game Theory approach for Platoon-based driving (GT4P) for video dissemination services in urban and highway VANET scenarios. GT4P encourages the cooperation between neighbor vehicles by offering reward (money or coupon) for vehicles participating in the platoon. In this sense, GT4P establishes a platoon by taking into account vehicle direction, speed, distance, link quality, and travel path, which reduces the impact of vehicle mobility on the video transmission. Simulation results confirm the efficiency of GT4P for ensuring video transmissions with high QoE support compared to existing platoon-based driving protocols.

  • JOSE MARIA DA SILVEIRA GOMES
  • A Socio-demographic  analysis of the Incidence of Leprosy in  Brazilian Legal Amazon: An approach based on Bayesian Networks 

  • Data: 08/02/2019
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  • The research aims to analyse the association of leprosy incidence in relation to indicators of human development, habitation and income level, considering the Brazilian Amazon region in relation to the entire country. An ecological study, based on data obtained on cases of leprosy in Brazil for the year 2010, made available by the Information System of Disease Notifications (SINAN) through the Informatics Department of the National Health Service (DATASUS) and the socio-economic indicators found in the Demographic Census Research database of the Brazilian Institute for Geographical and Statistical Survey – IBGE, as well as information from the Municipal Human Development Index, regarding education and income, obtained from the {platform} / website of the Human Development Atlas of Brazil, also for the year 2010. The methodology combined data mining with the analysis of spatial distribution. For municipalities of the Brazilian Amazon region the probability of presenting a high rate of leprosy incidence is 65.7%; but this value declines to 13.1% when the analysis contemplates other regions of the country.  When the data show that a municipality presents the lowest level of PopDensityAbove2 (<15.41%), the probability that this municipality does not present cases of the disease is 60%; on the other hand, when it presents the highest level (above 32.58%) this probability drops to 22.7%.      Using the Bayesian network model found, there is a significant association between the percentage of homes with more than 2 inhabitants and the rate of incidence of leprosy. Although the relationship between the rate of incidence, socio-economic factors (no water supply, no toilet, poverty and overcrowding of the home), low educational indices and income has already been reported in several studies, the insertion of the variable that considers population density of the home contributes to the discussion of the phenomenon.

  • PAULO TÁSSIO DA LUZ MELO
  • Total Cost of Ownership for 5G Communications Infrastructures for Smart Grid.

  • Data: 24/01/2019
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  • Smart Grid communications networks are considerably different from the traditional communication systems used to access the Internet when considering users, applications, Quality of Service and, especially, the impacts/losses due to malfunctions. Such data networks are generally owned and used exclusively by electrical system operators and require a high financial investment. Therefore, this paper presents an economic analysis to compare different possibilities of data network deployment for the Smart Grid. The results showed that 5G in comparison to other technologies obtained the best evaluation for the implementation of the communication of a data network applied to the Smart Grid, since the data of Quality of Service and the results obtained in the Total Cost of Ownership showed that in the medium and long term the 5G has its lower cost compared to other technologies used. Using a network configuration with 150 Femtocells and 2 Macrocells, Quality of Service obtained in regular and restricted transmission mode was 100% for uplink and 99.4% for downlink.

  • MARIANE DE PAULA DA SILVA GONÇALVES IMBIRIBA
  • Two-Level Allocation for H-CRAN Architecture Based in Offloading 

  • Data: 24/01/2019
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  • The accelerated data and apps growth represents significant challenges to the next generation of mobile networks. Amongst them, it is highlighted the necessity for a co-existence of new and old patterns during the transition of architectures. Thus, this paper has investigated solutions for offloading into a hybrid architecture, also known as H-CRAN (Heterogeneous Cloud Radio Access Network Architecture), that centralizes processing and searches a better use of the network resources. The strategy of optimization was analyzed through the evolutive algorithm PSO (Particle Swarm Optimization), in order to find a suboptimal solution to the allocation of two levels (TLA) in the H-CRAN architecture and another one based on FIFO (First In, First Out), for benchmarking purposes. SNR (Noise Interference Signal) average, Maximum Bit Rate, the number of users with or without connections and number of connections in RRHs and macro were used as performance measurements. Through the results, it was noticed an improvement of approximately 60% in the Maximum Bit Rate when compared to the traditional approach, enabling a better service to the users.

  • LESLYE ESTEFANIA CASTRO ERAS
  • A RADIO PROPAGATION MODEL FOR MIXED PATHS IN AMAZON ENVIRONMENTS FOR UHF BAND

  • Data: 22/01/2019
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  • The present work proposes a radio propagation model for the Amazon region called Mixed Path. The techniques used for Mixed Path model are Geometrical Optics (GO) and the Uniform Theory of Diffraction (UTD).  Only ten rays are considered the main contributors to calculate the total electric field. Increasing the number of rays does not improve the accuracy of Mixed Path model since the scenario is for receivers located in long distances. Then slope diffraction or multiple reflections means a low electric field that does not contribute significantly to the total electric field.  The parameters of Mixed Path model such as electrical constants, antennas height, buildings height among others, are analyzed in order to know the influence of them in the received electric field. Measured data in the central frequency of 521 MHz of a Digital Television station in the city of Belem of Pará are used to validate Mixed Path model. This city is located in the Amazon region of Brazil and presents mixed routes formed by city, river, and forest. Because digital television has a wide coverage and reception flexibility, Mixed Path was designed for receivers at the user’s level for the service of Mobile Digital Television (M-DTV) and for fixed receivers on the roofs of homes for Home digital television (H-DTV). Finally, the proposed model and other models in the literature are compared with the data measured for M-DTV, being Mixed Path the model with the lowest RMS error.

  • FREDERICO GUILHERME SANTANA DA SILVA FILHO
  • OPTIMIZATION OF THE POSITIONING OF MULTIPLE CELLS IN OUTDOOR ENVIROMENTS OF THE AMAZON REGION UTILIZING THE OPTIMIZATION ALGORITHM BY PARTICLE SWARM AND FLOWER POLLINATION

  • Data: 14/01/2019
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  • With the increase of the number of devices connected to the internet, by internet of things (IoT) or by personal communication, as smartphones and tablets, and consumers demanding even more access to high rates of date and quality of service, researchers all over the world have been investing great effort to draw the technologies of the next mobile generation (5G). A promising proposal is the utilization of millimeters waves to the new wireless systems, in view of, primarily, the enormous spectrum quantity available. However, it implies on the implantation of new services on high frequency bands. Despite of the expectation to reach even higher frequency rates with lower delays, the length of these waves makes this solution a huge challenge because the signal propagation in this condition is very hostile. The biggest smallcells exploration is also seen as a key technology to the evolution of the current mobile data to 5G, nevertheless the implantation of these cells in this type of scenery must be done in an optimized way to guarantee the data efficiency. This dissertation, is presented as a proposal of the optimization of multiple smallcells positioning in a densely wooded outdoor environment, using two bioinspired algorithms: Optimization by particle swarm (PSO) and Flower Pollination (FPA), combined with two propagation models of the next generation (5G): ABG e CI, simulated in different frequency bands: 3.5 GHz, 10 GHz, 24 GHz, 28 GHz, 60 GHz e 73 GHz. The specific analyzed environment is Batista Campos Square located in the city of Belem, in the State of Para. The results showed that both algorithms efficiently placed the smallcells, guaranteeing a better coverage on the extension of the square. In the OPS evaluation analysis, even though it executes in less time, it doesn’t converge to the optimum solution with the 1000 interactions utilized in simulations, being necessary a greater number of interactions, while the FP has a higher execution time, but it converges to the optimum solution with less than 500 interactions.    

2018
Descrição
  • MYLENA NAZARÉ MEDEIROS DOS REIS FERREIRA
  • The complexity of mental fatigue signals in healthy people is due to the absence of specific perturbations in the electroencephalographic activity, and by the singularity and variability of the cognitive profile of each individual. Identifying this mental state requires the analysis of several factors that involve the brain behavior in its regions in various frequency bands. In concern to the industry, mental fatigue compromises the efficiency of the production chain by affecting the perception (concentration and attention) of people, which increases the risk of accidents and production costs. Thus, monitoring the cognitive condition is necessary for the maintenance of the productive and cognitive performance of the evaluated subject. This work proposes the classification of fatigue using a competitive structure of Associative Neural Networks. This type of neural network allows to find the association between the input data and the reconstructed data from a compact architecture, being indicated for real-time applications. The characteristics vector used for classification is composed of the normalized information of three frequency bands (theta, beta and alpha) and four metrics that, according to the literature, differentiate mental states from electroencephalographic data in terms of Power Spectral Density. The results show the capacity and usability of autoassociative neural networks in patterns classification.

  • Data: 21/12/2018
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  • Associative Neural Network, Classification of mental fatigue, Cognitive performance

  • ERMINIO AUGUSTO RAMOS DA PAIXAO
  • OPTIMIZED MAPPING BETWEEN RRH-BBU LOOKING FOR BALANCING CHARGE IN C-RAN ARCHITECTURE USING INTELLIGENCE COMPUTATIONAL

  • Data: 20/12/2018
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  • The Cloud Radio Access Network (C-RAN) is an architecture proposition for next-generation mobile networks (5G), aimed at centralized management and processing, collaborative radio and real-time cloud computing. Such features enable this architecture to dynamically adjust the connections between Remote Radio Heads (RRHs) and Baseband Units (BBUs). However, if this feature is neglected, network problems such as blocked call and poor connection may occur. This work addresses this issue and proposes an optimized mapping model between RRH-BBU, seeking a fairer and more efficient balancing. In this sense, the Key Performance Indicator (KPI) of blocked calls was used to measure Quality of Service (QoS) metrics. In order to minimize them, an algorithm by Particle Swarm (PSO) was developed. A literature scenario composed of 19 RRHs distributed in a geographical area was used, which can be mapped in a BBU pool that manages two BBUs that have three sectors each. The initial configuration generated, on average, 80 blocked calls. Results obtained indicate a reduction of up to 100% of blocked calls and a more egalitarian load distribution among the BBUs. In addition, realistic scenarios with different user profiles were implemented, demonstrating that such factors directly impact the load generated by the BBUs and, consequently, affect their balancing. In order to verify the proposed formulation, in Network Simulator (NS-3) the same scenario used in the modeling was implemented, through the comparison of optimized and non-optimized scenarios, in order to the impact of serving more users in the network, where satisfactory results were obtained.

  • RAFAEL FOGAROLLI VIEIRA
  • Optimization of Resource Allocation in Hierarchically Distributed Data Centers

  • Data: 19/12/2018
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  • The rapidly increasing volume of services and applications, in addition to the high wireless access demand, are significant challenges for the next generation of mobile networks. The growth in the volume of applications is the reflection of the quantity of "things" that are being connected to the network and generating a huge data traffic. A new paradigm that is gaining recognition in the field of wireless networks, and is also responsible for part of this growth in the volume of services and applications, is the Internet of Things. The high amount of data that is generated by connecting those devices to the network will require significant computational resources to be processed and stored. A prominent  approach to handling such large amount of data is the use of Cloud Computing, which uses datacenters for storage and data processing. However,  traditional Cloud Computing, which has centralized resources, is not able to handle the high volume of data and the strict latency and Quality of Service requirements. Thus, to address such adversities, a new emerging concept known as Edge Cloud Computing has been proposed as an extension of the traditional Cloud Computing, bringing computational resources to the edge of the network and thereby creating a hierarchy of datacenters. In this way, the stricter requirements from services and applications, such as obtaining near-instant user experience, can be satisfied. In this work, a mathematical formulation for the dimensioning and provisioning of a hierarchy of DCs is proposed. According to the obtained results, the hierarchy of DCs provisioned and dimensioned using the proposed model can be better when compared to the others, being able to allocate 99\% of the set of applications that were used in the tests and to decrease the data flow in the backhaul links that is generated by the high number of applications the would circulate through the network. The analysis highlight the necessity of bringing computational resources to the network's edge in addition to an efficient applications allocation strategy in order to guarantee a better network performance.
     
  • IGOR RUIZ GOMES
  • POSICIONAMENTO ÓTIMO DE ESTAÇÕES RÁDIO BASE DO SERVIÇO MÓVEL CELULAR UTILIZANDO MODELO DE CONHECIMENTO DISCRETO EM PROPAGAÇÃO OUTDOOR

  • Data: 14/12/2018
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  • Modelos de propagação são muito utilizados para prever as degradações sofridas pelo sinal transmitido. Este trabalho tem o objetivo principal garantir a máxima área de cobertura, dentro da UFPA, tendo 2 e 3 torres para a propagação do sinal. O estudo da propagação leva em consideração tipos diferente de perdas e foi validado por dados coletados em 3 campanhas de medições em para frequências distintas. Os resultados mostram a maior área de cobertura para os cenários testados. O programa desenvolvido permite mudança de parâmetros, como altura, potência, quantidade de torres, podendo assim ser alterado para outros cenários. Todos os resultados obtidos foram comparados com outros modelos de literatura para salientar o melhor comportamento do modelo proposto. 

  • GABRIEL SILVA PINTO
  • Radiation Diagram Control of Graphene Dipoles by Chemical Potential

  • Data: 13/12/2018
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  • This works presents a method of controlling the radiation diagram of a graphene dipole by the chemical potential. The dipole analyzed has rectangular geometry with power suplly by voltage source in the center, where each arm of the dipole is maintained to a different chemical potential. The geometry is analyzed by the two-dimensional moments method, with an equivalent surface impedance. Calculations of the main radiative properties of the antenna are presented as a function of the chemical potential. The results show that the greater the different between the chemical potentials, the greater the displacement of the main lobe of the radiation diagram.

  • OTAVIO ANDRE CHASE
  • AUTONOMOUS SENSORY PLATFORM ARCHITECTURE IN THE CONTEXT OF ENVIRONMENTAL TECHNOLOGY FOR IN-SITU MONITORING OF ENVIRONMENTAL PARAMETERS AND THE SOLAR OVERIRRADIANCE

  • Data: 07/12/2018
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  • This thesis presents an in-situ sensing platform with architecture in the context of environmental and technology called PLACOT2AM (Convergent Transdisciplinary Platform to Amazonia). The platform is an integrated solution with sensors, data acquisition, processing, and wireless communication, through the technology of internet of things (IoT-Internet of Things). Also, the platform is a low-cost (hardware) and can be used as an alternative to proprietary tools and devices for data acquisition and processing in monitoring (micrometeorological and microscale level) of environmental parameters related to thermal comfort and super irradiance events. The platform has an expert system, which allows the simultaneous analysis of data acquisition of environ-mental variables. This makes it possible to generate knowledge to aid in decision-making in society about the extremes of environmental variability to bring health or productivity. In the first version, for monitoring of thermal comfort by temperature and humidity index (THI), the platform presents the most critical period in terms of high temperature and humidity (low thermal comfort) in a rural environment of Belém-PA occurs between May and October (2012), whose critical time is the 15:00, when humans and livestock production may suffer more with the thermal stress. In the second version, for monitoring of solar irradiance, the platform measures super extreme irradiance 1321 W/m2 in Belém-PA (12/05/2018), a low-latitude (1° S) and low altitude (7 m) above sea level. The architecture offers advantages in size, flexibility, energy autonomy, and cost; the project can be considered of low cost, with total R$ 350,00 (approximately U$$ 75). The results of the measurements and analysis expert present to PLACOT2AM as a good solution based on IoT for expert monitoring of environmental parameters and the events of overirradiance.

  • LUCAS FELIPE AMARAL
  • Comparison between load flow methods to active distribution grids.

  • Data: 04/12/2018
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  • This paper provides a performance evaluation of load flows methods to distribution power grids, considering them passives and actives. To that, the methods used were the following: Newton-Raphson, Fast decoupled with axis rotation, Fast decoupled with complex normalization and current summation. The performance evaluation of such methods were made considering the iteration number and the time processing that each method needed to converge, other criterion applied was the accuracy level of each method, through of the comparison of the voltages values taken by the Newton Raphson simulations related to the other 3 methods. Also, it was made in this work, comparisons of the performance of each method related to the iteration number on varying the r/x ratio of the test system feeders of  two buses, furthermore was verified the influence of the bases angles choices in the iteration number of the modified decoupled methods.

  • ULISSES CARVALHO PAIXÃO JUNIOR
  • Comparison of Computational Techniques of Linear Regression, Artificial Neural Networks and Decision Tree to Identify Harmonic Distortion in Electrical Distribution Grid

  • Data: 19/11/2018
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  • In recent years, the socioeconomic development of the population, the growth of the commercial and industrial sectors, as well as the growing installation of new loads, have generated a great evolution in the demand of electric power consumption. In turn, to obtain more efficient systems, the equipment manufacturers have been producing products increasingly fast and energetically more efficient for residential, commercial and industrial use. However, these loads, due to their non-linearity, have contributed significantly to the increase the levels of harmonic distortion of voltage and current. In the present work, emphasis is placed on the common coupling point (CCP) of two large consumers, that have different consumption and load characteristics, with the purpose of evaluating the harmonic impacts in their grid through computational techniques, in addition to comparing the level of reliability of the techniques by mean absolute error (MAE). The analyzes are based on real measurements in a university and an industrial pole, carried out with a minimum sample period of seven days through analyzers of eletric power quality, according to national quality procedures. The proposed methodology uses the techniques of Linear Regression, Artificial Neural Networks and Decision Tree to evaluate the harmonic contribution of each feeder at the point of interest of the chosen electric grids. As a result of the electric power quality, it was verified how much each feeder impacts the distortion of voltage and current in the CCP, besides classifying the feeders in relation to their respective impact in the studied electrical grid. Also, as a result, the study allowed the comparison of the three techniques among themselves, with different time intervals (weekly, daily and per load level), allowing to classify the behavior and reliability of each technique in each period. As a conclusion of the work, the proposed methods and analyzes presented allow managers to perform a more efficient mitigation action of the harmonic impacts caused in the electrical grid and, also, to identify the differences between the techniques and their degree of reliability, in accordance with the time intervals studied.

  • FLORINDO ANTONIO DE CARVALHO AYRES JUNIOR
  • RESEARCH OF ORDER CONTROL STRATEGIES FRACTIONS APPLIED TO ELECTRICAL AND INDUSTRIAL SYSTEMS

  • Data: 14/11/2018
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  • The use of control techniques are of a great matter to keep competitive performances, for electrical and industrials systems, having in mind as close as possible behavior setpoint tracking to a desired operation setpoint, aiming a reduced deviation and oscillation. In this work, are investigated fractional order automatic control techniques to improve the performance of industrial systems. Two fractional-order control techniques are studied, The Fractional Order Lead-Lag (FOLL) based on the frequency response method and applied to the improvement of power system stabilizers (PSS). Control laws are implemented in the form of digital control in an embedded system, based on DSPIC. The compensator’s performance is evaluated by performing several experimental tests on a 10 kVA reduced scale power system located at the UFPA Electrical Engineering Laboratory. Pulse in the generator voltage reference variation tests at are carried out at various power operation points of the microgenerator system, in addition to the robustness analysis of the system using a robust plot tool from the Bode diagram known as RBode. Second, there an investigation of a fractional pole placement technique (FOPP) that takes into account temporal response criteria of three terms fractional order systems, which in the case of this work are the overshoot and settling time, applied in a coupled tanks system, and a DC/DC Buck converter, where the FOPP technique is compared with two other techniques, the classical pole placement technique (IOPP), and a technique tuning of FOPID controllers based on Gain Margins and Phase Margins (GMPM). The results are corroborated for the two systems performing simulations in Matlab/Simulink Environment. The results show a reduction of at least approximately 15% in the ITAE and ISE indexes related to the dynamic performances of the systems addressed in this study, related to the controlled variable, with the insertion of the fractional controllers based on both the FOLL topology and the FOPP and GMPM techniques, compared to the values obtained from these controller indices tuned by conventional whole order techniques.

  • DIEGO KASUO NAKATA DA SILVA
  • PROPAGATION MODEL FOR MIXED PATHS USING DYADIC GREEN’S FUNCTIONS: A CASE STUDY FOR CITY-RIVER-FOREST PATH

  • Data: 09/11/2018
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  • This study provides a model using Dyadic Green's Functions for predicting the electric field in mixed paths for UHF. A new approach is used considering propagation in vertical layers to obtain new equations. The development of the model was accomplished in a mixed City-River-Forest path located in the Amazon Region. A measurement campaign was developed in Belém-Pará over Guajará Bay to obtain data in the proposed scenario. Measurement data were collected from a digital TV broadcasting transmitter. A comparative analysis was carried out among the proposed model, ITU-R P.1546-5, measurement data and ITU-R P.1546-5 using Millington’s curve-fitting. The measurement data and the model using Dyadic Green's Function are in a good agreement and have low RMS error values. The results confirm the efficiency and applicability of the proposed model.

  • PAULA RENATHA NUNES DA SILVA
  • INCIPIENT FAULT DIAGNOSIS IN TRANSMISSION LINES

  • Data: 26/10/2018
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  • Currently, the transmission system operation is overwhelmed by the large amount of information coming from the most different monitoring systems, which must analyzing this information to keep the system in acceptable operating conditions, according with Brazilian rules for power sector. In this sense, this present thesis proposes an on-line system for the diagnosis of faults in transmission lines. Such a method is predicated on the monitoring and analysis of the transmission line’s leakage current. More specifically, the system is composed of modules capable of self-adapting to scheduled improvements. The developed methodology specifically addresses the diagnostic module, which the characteristics of the faulty harmonic spectrum of the leakage current are extracted, and thereafter identifies the most prominent fault in a multi-event scenario. To extract leakage current signals characteristics, the analytical redundancy was used, which, from laboratory and field data, to determine the normal behavior of the LT, to elaborate the LT model in normal operation and with the anomalies. With normal and faulty leakage current is accomplished the feature extraction, which uses suitable algorithms based on features obtained from state of art and data from laboratory. After choosing the extraction algorithm that has the best performance for multiple faults, are proposed classifiers to determine the most prominent fault in the transmission line. The classifier design took into account that the system needs to adapt to the changes occurred in the transmission line, emboding the knowledge about the system, since this is very dynamic.

  • JUAN CARLOS HUAQUISACA PAYE
  • Calculation of Technical and Non-Technical Losses In Power Distribution Networks using the Equivalent Opeerational Impedance  Definition

  • Data: 17/10/2018
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  • This work presents a new concept called Operational Equivalent Impedance (OEI), which is characterized by being a practical and economical method that allows calculating technical and non-technical losses in electricity distribution networks with good accuracy, for which it uses the data that any electric utility has, such as the user's electricity bills, the grid's electrical parameters and the measurements of power and currents at the substation coupling point. To show the application of this method, this document covers the data processing and description of the software used to simulate the operation in the test systems  IEEE  13 and 37 buses networks, considering that they present technical and non-technical losses. In addition, these systems are evaluated with different operational conditions, including the incorporation of a photovoltaic plant. The cases evaluated in this work show that the method can be used to plan and monitor the electricity distribution networks, considering the separation of technical and non-technical losses, so that in future  reduction actions concerning these losses can be managed, since of unmanaged electricity losses is  translated into considerable economic losses for both the utility and customers and indirectly for the country. The results presented in this dissertation, regarding the application of the Equivalent Operational Impedance to the calculation of technical and non-technical losses, have demonstrated the effectiveness of the proposed methodology, so that it is foreseen a great potential for the application of the proposed procedure in the electrical sector mainly in the distribution utilities.

  • ANTONIO THIAGO MADEIRA BEIRAO
  • Majorana bound states in quantum dot device coupled with superconductor zigzag chain.

  • Data: 11/10/2018
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  • The research in condensed matter physics with insulators and superconductors topological has contributed greatly to the characterization of the surface properties and modes zero in nanowires. We investigate theoretically, through the recursive Green’s function approach, the electron transport through the T-shaped quantum dot (PQ) with a single level and spinless, connected to a zigue zague chain and coupled to a p-wave superconductor. This model is an extension of the Kitaev chain for a network triangular of finite-size with for three, four, and five sites. We find that the Majorana zero modes can be tuned through the coupling parameters of the device and the linear conductance show both the Majorana Bound States (MBS) in topological phase and in the general topological phase maximally robust. This more realistic model allows the detection of MBS through of the control of the parameters governing the electronic tunneling and can be helpful for relevant experiments.

  • JANILSON LEAO DE SOUZA
  • Broadband Dipole-Loop Plasmonic Optical Nanoantenna

  • Data: 11/10/2018
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  • this work a new model of plasmonic optical nanoantenna is analyzed. The nanoantenna denominated dipole-loop is obtained by a combination of a cylindrical dipole antenna and a cylindrical parasitic loop. This new antenna model is investigated and applied in plasmonic optical nanocircuit and wireless optical nanolink. The modeling of the antenna and of their applications are done by the linear Method of Moments (MoM). For the nanoantenna, the input impedance, reflection coefficient, bandwidth, radiation efficiency, gain, electric near-field, radiation pattern, and the effect of a silicon dioxide substrate on the resonant properties of the antenna are investigated. However, the principal focus is bandwidth. For the nanocircuit, the impedance matching is investigated, applying the concept of impedance matching in analogy with the radiofrequency theory, by varying the parameters of the emitting antenna. For the nanolink, the power received in the load is analyzed as a function of frequency and distance between transmitter and receiver. In addition, a comparison is made of the loss with the distance of the link with a bifilar OTL. The results show that the dipole-loop antenna presents an evident characteristic of wide bandwidth, with values up to 45.4 % and, in general, this bandwidth was between 36.7 and 45.4 %. This antenna applied an nanocircuit can improved the impedance matching degree (minimum reflection coefficient of −25 dB) in relation to the dipole antennas. In addition, when used in wireless optical nanolink the operating bandwidth in the range of 179.1 to 202.5 THz can be increased compared with conventional nanolink based only on dipole antennas. In addition, when used in wireless optical link it can be increased the operational bandwidth in the range of 179.1 to 202.5 THz compared with conventional nanolink based only on dipole antennas. In addition, wireless nanolinks, based on dipole or dipole-loop antennas, are more suitable than wired nanolink for distances above approximately 22 μm.

  • CHARLLENE DE SOUSA GUERREIRO
  • MAERNI - EVALUATION MODULE FOR EXPOSURE TO NON-IONIZING RADIATION FROM DIGITAL TV AND FM RADIO TRANSMISSION ANTENNAS FOR A 3D VIRTUAL ENVIRONMENTAL TOOL

  • Data: 09/10/2018
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  • In recent years given the technological advancement of the communication media, and the increasing of users demand who wants a high quality of these services offered to them, the companies have increased the number of Radio Base Stations in cities, where many of these are located in environments with high housing density. Considering that each antenna or set of antennas present in these stations have an electromagnetic field of radiofrequency and transmit radiation, the concern with the population living in the adjacency of the transmitting antenna is the studies object of systems than regulate the companies that offer radiofrequency services, as well as, is the object of studies that aim not only to discover the effects of the contact with the ionizing and non-ionizing radiation present in these fields, but also to find out if the standard established for the regulation of services is being fulfilled. In this work presents the stages of development of a module, which consists of an extension added to the simulator for planning mobile communication networks (SIMPLARCOM). The module proposed allows, through the Virtual Reality environment (VR), to build and configure different scenarios, as well as the parameters of the transmission antenna, to provide an environment for non-invasive tests to evaluate non-ionizing radiation exposure; and identify potential insecure areas for housing, providing information for aid in decision-making regarding the relocation of transmitter antennas and aiming to decrease the ERP (effectively radiated Power) radiated by these Antennas. The module considers the guidelines present in resolution Nº. 303, published by the National Telecommunications Agency (ANATEL). In the results obtained is possible, navigate through the constructed scenario and check the value of the received power, the field intensity, the operation frequency, the antenna being analyzed and whether a certain point in the scenario is or is not receiving radiation at according to the threshold permitted by ANATEL.

  • CARLOS RAFAEL MARQUES DOS SANTOS
  • Faraday and Kerr effects in periodic metal structures: Graphene in THz range and Gold-Dielectric-Bi: YIG in infrared range.

  • Data: 05/10/2018
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  • The photonics is a research field whose purpose lies in the use of light (photons), rather than electrons (electronics) in the realization certain functions such as storage, transfer and processing of signals. In this context, it opens the possibility of development and production of devices whose storage capacity surpasses those of electronic devices. To do this, it is necessary to control the photons similarly, to what is done in electronics with the electrons. The control of radiation, in the context of photonics, can be realized through magneto-optical effects, such as the Faraday and Kerr effects. The Faraday effect is used as the basis of operation of devices such as optical isolators, current sensors and others. In turn, the Kerr effect is the basis of the operation of data storage devices (optical magnetic memory). In the present work are studied magneto-optical effects of Faraday and Kerr, as well as the transmission of electromagnetic radiation in the regions of terahertz and infrared. In the frequency range that corresponds to the THz is analyzed the Faraday effect, the Kerr effect and the radiation transmittance in periodic structures of graphene with different geometries. The structures analyzed in this work can present RF, for weak magnetic fields  (1T, for example), greater than 3° depending on the choice of geometry that can be circles, squares, squares with small cuts in the corners and ribbons. Faraday rotation in these systems can be explained by a simple circuit model where the introduction of periodicity in the graphene promotes the increase of the system impedance and consequently changes the magneto-optical properties of the system, improving the rotation of Faraday at high frequencies (larger 7 THz) still with magnetic field values taken as weak. This characteristic can not be obtained in a uniform sheet of graphene, since, for this, it is possible to obtain a strong rotation of Faraday at high frequencies with strong magnetic fields (10T, for example). Additionally, for the three periodic structures it was calculated the rotation of Kerr that can reach the value 2.6° depending on the geometry chosen. For all cases, the maximum frequency of Faraday and Kerr rotation occur for frequencies greater than 7 THz. These results are better if compared to the results already published. In the infrared region are studies the effects of Faraday, Kerr, as well as extraordinary optical transmission in a plasmonic hybrid structure composed of four layers. For this, the Faraday rotation is of 7.9° and 0.25 of transmittance for wavelength 945 nm. Additionally, the Kerr effect can reach 23°. These results are better if compared to the results already   published. In the proposed structure, the improvement of Faraday’s rotation is due to the increase of the Q factor of the resonances in the magneto-optical material layer.

  • ANDRE FELIPE SOUZA DA CRUZ
  • Analysis of Plasmonic Sensor in Coupled Emission Configuration by 3D Green`s Function

  • Data: 28/09/2018
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  • In the present work, the theoretical study on a plasmon resonance sensor in the Surface Plasmon Coupled Emission (SPCE) configuration is presented. Coupled to the sensor structure is a microfluidic channel containing suspended target particles (gold nanoparticles functionalized to attract fluorescent molecules), which when excited and immobilized upon the sensor structure can be efficiently modeled as a planar array of induced dipoles. The electromagnetic modeling of the device was performed through the magnetic potential, defined through the Periodic Green Function (PGF) 3D. The electromagnetic fields are presented in terms of the discrete spectral representation through the complex double Fourier series, and to reduce the number of terms in the series, it’s proposed to use the Euler identity. Parametric field results are presented in the sensor structure, and in a second analysis, the spectral analysis of the potential field is performed, in this it’s verified the arising of the SPP and SW poles in the spectral domain. For the validation of the method, the limit case was analyzed, in which the particles are distant from each other, and compared with published works. Finally, results and discussions about the convergence of series in the cosine PGF are presented. The results show good agreement, showing that the theoretical method of PGF 3D is efficient, and can be used as an auxiliary tool in the design of this sensing device.

  • MAURO GOMES DA SILVA
  • PROJETO DE CONTROLADOR PREDITIVO: ABORDAGEM POLINOMIAL E NO ESPAÇO DE ESTADOS

  • Data: 28/09/2018
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  • PROJETO DE CONTROLADOR PREDITIVO: ABORDAGEM POLINOMIAL E NO ESPAÇO DE ESTADOS

  • ANTONIO RONIEL MARQUES DE SOUSA
  • Multi-physical Analysis via Finite Element Method for Predictive Maintenance Assistance in Power Transformers.

  • Data: 21/09/2018
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  •  
    SIN (National Interconnected System) is a system of fundamental importance in the panorama of the Brazilian electrical system. Its function is to electrically connect generating centers and consumer centers, whether they are business, commercial or residential. The main equipment responsible for the connection and transmission of electric power from the generating centers to the consumers are the power transformers. This equipment is subject to several types of faults that can affect its components, in some cases compromising the operation of this equipment, and consequently the supply of electric energy. In this work, a multiphysical analysis is performed on power transformers, coupling thermal and structural electromagnetic simulations with the objective of providing the operator with information about the ideal moment for performing predictive maintenance, avoiding unplanned shutdowns. For this, computational simulations using the Finite Element Method (MEF) were used and from this, we analyzed the different situations that these equipments can be submitted, in the nominal condition, as well as extreme conditions of operation like current of inrush and current short-circuit. In this perspective, analyzes of the effects that the thermal expansion and the axial forces and radia exerted contributing to possible defects in these equipments were carried out. As a study object, the simulations were performed in a 50 MVA single-phase transformer, which is an equipment that is in operation in the northern region of the country. For a more validation of the methodology used in this work the simulations were validated with real measurement data and with results present in current literature. In this way, this work presents a methodology that can help the technical framework of an industry in the decision of the appropriate moment of stop in a power transformer for the accomplishment of predictive maintenance
  • PAULO ANDRÉ IGNÁCIO PONTES
  • THE DEVELOPMENT AND EMPIRICAL EVALUATION OF AN EDUCATIONAL SIMULATOR FOR THE SUPPORT OF ECG EDUCATION BASED ON SPACE ORIENTATION OF THE HEART

  • Data: 21/09/2018
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  • An electrocardiogram (ECG) is one of the most widely used diagnostic procedures in medicine, so it is essential that medical graduate students learn to interpret it correctly while they are still training. Of course, students go through classical learning (eg lectures and speeches). However, they are generally not efficiently trained in the analysis of ECG results. In this regard, educational support methodologies and tools in medical practice, such as educational software, should be considered as a valuable approach for medical training purposes. This thesis deals with the development of a simulator (VETOECG ) that allows experiential teaching so that students can relate to projections of the cardiac electrical vectors by manipulating the spatial orientation of the heart and the repercussions on their respective ECG waves. In addition, this thesis reports a formal experiment to empirically evaluate the learning effetiveness of the tool and the students' perceptions regarding motivation user experience and learning, comparing with traditional ECG teaching methodologies. As results, it can be verified that the simulator is adequate in the most diverse dimensions, since they were evaluated positively: in terms of motivation (88.15%), user experience (76%) and learning (96.5%). The results also indicated that the simulator has positive learning efficacy compared to the traditional methodologies (statistically significant difference) used for learning in the proposed study, thus, it can be considered an alternative to teach ECG interpretation. In a complementary way, a systematic review of the literature was carried out to verify the non existence of a simulator that teaches ECG interpretation by manipulating the spatial orientation of the heart and allowing visualization of the projections of the cardiac electric vectors in the leads and the repercussions on the behavior of the respective on the ECG.

  • DIONE JOSE ABREU VIEIRA
  • Decision Tree-Based Preventive Control Applications to Enhance Fault Ride Through Capability of Doubly-Fed Induction Generator in Power Systems

  • Data: 21/09/2018
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  • The development of a preventive control methodology to increase the capacity of voltage sag recovery (Fault Ride Through Capability (FRTC)) of a doubly-fed induction generator (DFIG) connected in an electrical network is presented. This methodology, which is based on the decision trees (DT) technique, assists with monitoring and support for security and preventive control, ensuring that wind systems remain connected to the power system even after the occurrence of disturbances in the electric system. Based on offline studies, DT discovers inherent attributes of the FRTC scenario related to electrical system behavior and provides a quick prediction model for real-time applications. From the obtained results, it is possible to check that the DFIG is contributing to a system’s operation security from the availability of power dispatch and participation in the voltage control. It is also noted that the use of DT, in addition to classifying the system’s operational state with good accuracy, also significantly facilitates the operator´s task, by directing him to monitor the most critical variables of the monitored operation state for a given system’s topological configuration

  • GILBERTO NERINO DE SOUZA JUNIOR
  • Generation of teaching tasks adapted through bio-inspired algorithms for early literacy children

  • Data: 14/09/2018
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  • Advances in learning systems over the past two decades have enabled the development of technologies that help the engagement of students. Although these systems may use behavioral procedures to improve reading skills, better outcomes for each student are obtained in the manual elaboration of the set of tasks by an educational expert; however, the use of a manual process ends up causing too much time, effort and subjectivity for the creation of tasks. Additionally, even with the aid of computational processes, the automatic generation may be impracticable due to the high search space for the possible combinations of tasks. This complexity increases when considering the adaptation of the difficulty to the student's knowledge, following a flow of teaching and maintaining diverse tasks for the study. This thesis presents a new method for generating teaching tasks from the Matching-to-Sample procedure, adapting its difficulties through bio-inspired optimization meta-heuristics. Experiments demonstrated a better convergence of the genetic algorithms for this domain, being able to generate tasks on a level of difficulty adapted to the students and according to pretests and configurations of attributes of the tasks, defined by behavioral psychologists. As a case study, the tasks were applied to a group of students in the early stages of literacy, achieving satisfactory effects in the individual learning process. In addition, in order to present the teaching tasks to the children, two interactive learning software were implemented as a digital game and a web system, where the use of the digital game with playful features showed superior acceptance in the use of teaching tasks adapted to children in early literacy.

  • CARLOS EDUARDO MOREIRA RODRIGUES
  • Análise de Supraharmônicos em Equipamentos Eletrônicos e Caracterização Utilizando a Transformada Wavelet

  • Data: 10/09/2018
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  • This dissertation aims to analyze the emission, propagation and interaction between equipment involving harmonic components that have a frequency in the range between 2 and 150 kHz, called supraharmonic. For the proposed analysis, measurement campaigns were carried out on frequency inverters, UPS, LED lamps and a notebook source. The measurements were divided into two distinct groups: with the equipment connected to the electrical network and a three-phase electronic source, in order to verify the orders and levels of both the emissions from the equipment and the distortion emitted by the electronic source itself, besides the interaction between the source and the equipment fed. The Fourier Transform and the Wavelet Transform were used to perform the analysis and characterization of the observed distortions. The measurements showed a significant contribution of the equipment observed and the electronic source for the emission of supraharmonics, besides the amplification of the distortion when the equipment is fed by it.

  • HELIANA MARIA CEBALLOS AGUILAR
  • Thermal and Energetic Performance of a Building in the Brazilian Amazon Region

  • Data: 06/09/2018
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  • The consumption of electrical energy in buildings has been increasing gradually over the years. Estimated that buildings account for 40% of the world's energy consumption and 50% of CO2 emissions, one of the sectors that most influence the environment. In this context, there is a need to design buildings with low energy consumption, while at the same time provide the user with more comfort, through the application of bioclimatic strategies, optimization of natural resources and use of efficient equipment. In this work, studied innovative proposal of integration of several strategies to reduce energy consumption, where the impact of each one of them is evaluated individually, and all together, in the thermal, energy and economic performance of a building located in the Brazilian Amazon Region. High temperatures and humidity characterize this region climatically, where achieving adequate comfort conditions implies a high demand for energy for air conditioning systems. Evaluate different energy Conservation Measures in order, to achieve a better use of daylighting. In addition, to reduce the thermal loads for cooling, with the installation of a thermal insulation material is considered in the east and west walls, and of a thermal insulation and air chamber in the roof, which are the external surfaces that receive greater solar radiation in the building. Additionally, various systems of photovoltaic generation, one of which integrated as an architectural element and another is adapted on the roof of the building. In the building, two types of analysis executed dynamic and static. For the dynamic analysis, the EnergyPlus software used to know its thermal and energy consumption performance analyzed for the entire year and for the date design day, and the Daysim/Radiance software to know the autonomy of daylighting attained, for both using data measured by an on-site meteorological station. About the static analysis, the level of energy efficiency evaluated by the prescriptive method according to the current national regulations. With the assessments performed, it is determined that the Energy Conservation Measures (MCE) have a direct and significant influence on the reduction of the thermal load for cooling, the reduction of radiation effects, the shading in the eaves and the reduction of the transmittance of the surfaces treated. It is also verified the possibility of maximizing the daylight in internal spaces, to improve the comfort of the users, allowing their better performance and energy saving used in artificial lighting. In terms of energy consumption and economic feasibility, ECM achieve an annual energy savings of 52% in the building taken as a case study, and the solutions adopted show a return on financial investment, and are also suitable for energy saving and economically feasible in regions with similar climatic characteristics

  • ANDERSON VINICIUS DE FREITAS SOUTO
  • Estratégia para Otimização de Offloading entre as Redes Móveis VLC e LTE baseada em Q-Learning

  • Data: 31/08/2018
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  • Estratégia para Otimização de Offloading entre as Redes Móveis VLC e LTE baseada em Q-Learning

  • RODRIGO DIAS ALFAIA
  • MGI: Intelligent management module for optimizing the user's thermal comfort in Smart Home.

  • Data: 31/08/2018
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  • The motivation to integrate energy efficiency in electrical equipment has been increasing during the last years. A portion of this growth results from incentives and the implementation of standards that help in the supervision and regulation of minimum specifications for efficiency of electric energy consumption by equipments. In addition, with the growth of technology and access to information, new forms of intelligent management are suggested to help optimize energy consumption. This study presents the specification and development of the intelligent module, to be integrated in the Smart Consumption Management Architecture (SmartCoM), which involves meteorological data (temperature and humidity) collection and analysis via the communication interface characteristic of the architecture, from Internet of Things (IoT), to intelligent management of an air conditioner with the goal of optimizing energy consumption mainteining residents thermal comfort. The methodology simulates a residential environment so that the MGI can provide an ideal temperature, and as a result, has proved to be efficient in reducing energy consumption compared to the conventional model. Experiments were carried out to estimate energy consumption of air conditioner through year 2017. The experiment consisted in reducing energy consumption while maintaining thermal comfort and achieved an average annual reduction of 24.5\% during night period and 21.1\% during daytime being within the standards of thermal comfort established by national and international standards.

  • DAVID BARBOSA DE ALENCAR
  • Hybrid model based on time series and neural networks to predict the generation of wind energy

  • Data: 30/08/2018
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  • The electric power generation through wind turbines is one of the practically inexhaustible alternatives sources of electric power. It is considered a source of clean energy, but still requires a lot of research to develop science and technologies that ensure uniformity in generation, providing a greater participation of this source in the energy matrix in Brazil as in the world, because the wind presents abrupt variations speed, density, and other important variables. In wind-based electrical systems, each forecast horizon is applied to a specific segment, forecast of minutes, hours, weeks, months, and future years of wind behavior, in order to evaluate the availability of energy for the next period, relevant information in the dispatch of the generating units and in the control of the electric system. This thesis aimed to develop ultra-short, short, medium and long-term prediction models of wind speed, based on computational intelligence techniques, using Artificial Neural Networks, SARIMA models and hybrid models and to predict the generation capacity of power for each horizon. For the application of the methodology, the meteorological variables of the database of the national environmental data system SONDA, Petrolina station, were used for the period from January 1st, 2004 to March 31st, 2017. The performance of the models was compared with 5, 10 and 20 steps forward, considering minutes, hours, days, weeks, months and years as the forecast horizon. The hybrid model obtained better response in the forecasts, among which the hour horizon was highlighted.

  • JACKSON MOREIRA OLIVEIRA
  • ALL-OPTICAL LOGIC GATES BASED ON MICHELSON INTERFEROMETER WITH SEMICONDUCTOR OPTICAL AMPLIFIER

  • Data: 24/08/2018
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  • In this work, we propose all-optical logic gates device structure based on a Michelson interferometer (MI) composed of semiconductor optical amplifier (SOA) forming a structure of SOA-MI logic devices with symmetrically identical Fiber Bragg Grating (FBG) at the output of each of its arms, for a numerical simulation of the all-optical AND, OR and NOR logic gates of two binary input signals with different bit numbers using the cross-gain modulation (XGM) technique at 10 Gb/s bit rate and filter bandwidth at 10, 20 and 40 GHz using OptiSystem 15.0 software by OptiWave Corporation, to demonstrate and extract simple design rules for high-speed optical processing and analysis of non-linear SOA-induced properties. In addition, this work includes the study of the effect of bandwidth and number of bits on received power, minimum bit error rate (BER), maximum quality factor (Q-factor), Optical Signal to Noise Ratio (OSNR) and optical spectrum, which demonstrates high-speed gates and performance. We run the SOA-MI-based logic gates with some parameters and the results can demonstrate a structure of high-performance optical logic devices with high speed.

  • WALTER DOS SANTOS OLIVEIRA JUNIOR
  • Management of information technology in education: the use of digital educational games and the impact on motivation and learning

  • Data: 24/08/2018
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  • Among the recent innovations in the teaching-learning process, the use of digital educational games has been highlighted. Knowing its effectiveness is the responsibility of educators, developers, researchers and managers. This work investigates the implementation of a digital application called "Matematicando" in public schools in the state of Pará. During six months in 2017, it was followed the implementation of this application, observing the evolution of the school grades of 157 students, from the fifth year of elementary education, in the age group from 11 to 13 years old in two cities in Pará. Additionally, the relationship between the use of the digital educational game and the motivation of students and teachers in other 75 schools in a municipality of Pará was investigated. The experiment examined the correlation between the use of the digital educational game, school income as independent variables and related aspects infrastructure, students and teachers, as dependent variables. For the analysis of the evolution of the grades the sample population was divided between students exposed to the game and students not players. The results revealed that there were gains in the 12% mark among students who had contact with the game and a decrease of -1.0% among those who did not use the game. When compared to the hours of exposure to the game, the students who used the most (192 hours) presented a 45% higher yield compared to those who used less (24 hours). As for the correlation between the presence of Internet connection and the computer lab and the use of the game, a medium advance was found between those who do not have neither the Internet nor the laboratory a 2% advance in the income, while the schools connected to Internet and have a computer lab grew by an average of 14%. Based on the results obtained, it is expected to contribute with managers and educators regarding the use of technology and information management in the daily life of educational institutions, especially regarding improvements in the multiple relationships that collaborate with a more efficient educational environment.

  • DOUGLAS DA ROCHA CIRQUEIRA
  • A Preprocessing Architecture for Sentiment Analysis for Social Media in Brazilian Portuguese

  • Data: 23/08/2018
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  • The Web 2.0 has been pushing the emergence of a diversity of platforms for people interaction, which enable the dynamic sharing of information, and which daily creates a massive amount of unstructured data from social media and online social networks, such as Facebook, Twitter, and Instagram. Such platforms have been adopted not only for entertainment but also to users keen to share their opinions regarding restaurants, bars, and products they have visited or bought. This scenario reveals a potential treasure for companies and institutions, which seek improvements in their products and services, based on the feedback from their customers. Brazil is a highlight in this scenario, where this phenomenon can be observed, as the Brazilian population is one of the most communicative in the world, as well as most active in social media platforms. In this context, the application of data mining in Brazilian social media can be beneficial both for companies, that can get to know how they should improve their offers, as well as to consumers, that can have their needs and suggestions implemented by such companies. In this context, the computational technique of Sentiment Analysis can play a role, as it is an application of Natural Language Processing, which applies Text Mining to infer the polarity regarding the sentiment associated to documents, usually referred as positive, negative or neutral. Such documents may be comments on Online Social Networks or user reviews in ecommerce platforms. However, this technique faces challenges, reported in the state of art, when dealing with the social media scene. For instance, the user-generated content in Online Social Networks is usually ungrammatical. Such elements impose barriers to the advancements of Sentiment Analysis in this context, whether for free-available or commercial platforms, which work with text mining. Besides, the existing approaches in the literature of Sentiment Analysis for social media in Brazilian Portuguese, in general, present their own set of preprocessing steps, without a defined standard in this research area. Therefore, this project proposes a novel architecture for preprocessing social media content, in Brazilian Portuguese, for Sentiment Analysis. This proposal employs an expanded number of data treatment steps reported in the state of art, in order to provide enhanced features for a sentiment classification module. The innovative aspect is related to the tasks applied, as well as to their implementation methodologies. The proposal was compared with stable baselines in the literature, in order to have confidence in a comparison with the state of art. The obtained results reveal that an expanded set of preprocessing steps can improve the performance of Sentiment Analysis in the Brazilian context, and enrich possible analyses concerning consumer’s opinions in social media.

  • THIAGO RODRIGUES BRITO
  • MEASUREMENT OF SOLUAL PHOTOVOLTAIC MODULES THROUGH TWO CAPACITIVE LOADS

  • Data: 16/08/2018
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  • With the increasing demand for electricity worldwide, renewable energy sources are increasingly acquiring space in the world’s energy matrix. In this context, photovoltaic energy has stood out with high growth rates. However, it is necessary to have means to evaluate the performance of the photovoltaic modules. This can be done by means of its characteristic I-V curve, from which the module’s electrical parameters can be evaluated and used as an indicator of possible manufacturing faults, connection or shading. The use of solar simulators is a faster and more reliable to obtain such I-V curve. However, the high costs of a simulator limits access to such measurement, moreover, it is limited to measure only a single PV module. This work seeks to evaluate a methodology for the I-V curve acquisition under outdoor conditions by using two capacitive loads and a reference module as irradiance and temperature sensor. The standard test conditions are obtained by means of IEC 60891 procedures. Silicon technology modules were tested and their results were compared with indoor measurement, using the solar simulator located at GEDAE/UFPA solar laboratory. The results indicated that, depending on which calculation method and considerations related to temperature, this can be a suitable methodology for the measurement of a photovoltaic module.

  • ZAIRE DE ASSIS FERREIRA SOUZA
  • UTILIZAÇÃO DE SISTEMA DE ARMAZENAMENTO TÉRMICO PARA APLICAÇÃO DE GERENCIAMENTO PELO LADO DA DEMANDA EM UMA REDE DE DISTRIBUIÇÃO UNIVERSITÁRIA

  • Data: 16/08/2018
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  • The present dissertation proposes the optimal management of the refrigeration demand of a university distribution network to promote greater economy and energy efficiency using the thermal inertia of air-conditioned classrooms as storage element of thermal energy and photovoltaic generation. The proposed method considers the hourly variation of the ambient temperature influencing the variation of the internal temperature of the classrooms and the consumption of energy throughout the day, knowing that the consumer unit is charged in the Horo-Sazonal Green model. The analysis of the loads of the consumer unit leads to the conclusion that most of the energy consumed is destined to some kind of refrigeration load, especially to ambient air conditioners, thus, to consider the management of this type of loads in the context of the smart grids is a coherent way of positively impacting on increasing energy efficiency. Demand side management is based on Genetic Algorithm and the results prove the effectiveness of the proposed method in balancing the energy management and promoting a considerable increase in the economy with the energy expenses.

  • ALBINO MOISES FARO DE MORAIS JUNIOR
  • PREVISÃO DE DISTORÇÃO HARMÔNICA EM CARGAS RESIDENCIAIS UTILIZANDO REDES NEURO-FUZZY

  • Data: 11/07/2018
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  • With the increasing use of nonlinear loads in homes in Brazil comes the problem of harmonic injection in the power system and increasingly is a problem for the electric sector that needs to scale it. Knowing the loads that consume energy and inject harmonics into the system is important so that solutions are sought to make the use of the system more efficient and improve the quality of the energy that circulates in the electrical grid. This work presents simulations of DHTv and DHTi of a set of residences in order to predict the behaviour of the load over time, using previous measurements. The modelling is conducted using an ANFIS, which uses a neural network to adjust the parameters of the output that uses fuzzy rule to determine the output values of the system.

  • KETYLLEN DA COSTA SILVA
  • Estratégia de Planejamento e Otimização do Handover em Redes Móveis Densificadas

  • Data: 29/06/2018
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  • A explosão do uso de dispositivos e aplicações móveis nos últimos anos, tem levado a uma sobrecarga da infraestrutura da rede responsável pelo escoamento desse tráfego, afetando  tanto o desempenho da rede quanto a experiência do usuário. As redes móveis heterogêneas já são realidade e sua densificação tem sido apontada como uma das soluções propostas para atendimento das demandas esperadas para as redes celulares de quinta geração (5G). Nas redes atuais, no entanto, ainda é comum o uso de parâmetros fixos na configuração da rede, mas esta estratégia nem sempre se mostra eficiente. É dentro deste contexto que se consolida o conceito de redes auto organizáveis nas quais os vários parâmetros da rede são ajustados automaticamente com base em medições em tempo real e sistemas inteligentes. Esta tese apresenta uma estratégia para otimização de handover em redes LTE com densa implantação de small cells. Com base em medições e lógica fuzzy são propostos dois novos algoritmos para o auto ajuste de parâmetros da rede. A partir de simulação discreta utilizando o MATLAB, os resultados são obtidos e apresentados através das principais métricas de avalição de desempenho de handover.

  • IVAN RUY DE PARIJOS JUNIOR
  • AVALIAÇÃO OPERACIONAL DOS EFEITOS DE DEMANDA DE QUATRO SISTEMAS DE MICROGERAÇÃO FOTOVOLTAICA CONCECTADOS À REDE

  • Data: 29/06/2018
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  • O TEMA QUALIDADE DE ENERGIA ELÉTRICA (QEE) É AMPLAMENTE PESQUISADO NO MEIO CIENTÍFICO, ENTRETANTO, NAS DIVERSAS BIBLIOGRAFIAS E TRABALHOS ACADÊMICOS PRODUZIDOS NÃO EXISTE UMA DEFINIÇÃO ÚNICA SOBRE O QUE É QEE. DIVERSOS FENÔMENOS QUE AFETAM A QEE, E SUAS CONSEQUÊNCIAS, TÊM SIDO INVESTIGADOS. QUANDO DE TRATA QEE ENVOLVENDO A OPERAÇÃO DE UM SISTEMA FOTOVOLTAICO CONECTADO À REDE, A PREOCUPAÇÃO PRINCIPAL É COM A OPERAÇÃO DO INVERSOR, EQUIPAMENTO ESSE RESPONSÁVEL POR FAZER A INTERFACE DO GERADOR FOTOVOLTAICO COM A REDE. A INSERÇÃO DA GERAÇÃO FOTOVOLTAICA NA REDE ELÉTRICA REQUER ATENÇÃO ACERCA DE CERTOS FATORES COM A ALTERAÇÃO DA CURVA DE CARG DE UNIDADES CONSUMIDORAS, BEM COMO A ELEVAÇÃO NOS NÍVEIS DE TENSÃO, A PRESENÇA DE COMPONENTES HARMÔNICAS NO SINAL DE CORRENTE DA SAÍDA DO INVERSOR E A VARIAÇÃO DO FATOR DE POTÊNCIA DA UNIDADE CONSUMIDORA. ESTE TRABALHO FOI PENSADO COM O INTUITO DE REALIZAR TESTES E AVALIAR AGUNS ASPECTOS QUE PODEM INFLUENCIAR A QUALIDADE DA ENERGIA COM A INSERÇÃO DE GERAÇÃO FOTOVOLTAICA NA REDE DE DISTRIBUIÇÃO, MAS TAMBÉM ASSOCIADO COM O PERFIL DE DEMANDA DO CONSUMIDOR. PARA ISSO UTILIZOU-SE QUATRO SISTEMAS FOTOVOLTAICOS CONECTADOS À REDE (sfcr), BEM COMO FOI DESENVOLVIDA UMA BANCA DE TESTES E AQUISIÇÃO DE DADOS PARA MONITORAR A OPERAÇÃO DESSES SISTEMAS. NESTE TRABALHO É POSSÍVEL OBSERVAR QUE A OPERAÇÃO DOS SFCR PROVOCA ALTERAÇÕES NOS NIVEIS DE TENSÃO NO PONTO DE ACOPLAMENTO COMUM, BEM COMO A INTERAÇÃO SFCR E CARGA CAUSA ALTERAÇÕES NO PERFIL DE DEMANDA MEDIDO PELA REDE, IMPLICANDO EM UMA DISTORÇÃO HARMÔNICA TOTAL NA CORRENTE (THDI) E FP  MEDIDOS PELO LADO DA REDE, DIFERENTES OS MEDIDOS  NA CARGA E NA SAÍDA DO INVERSOR.

  • ELEANOR DIAS DE SOUSA
  • Grau de Confiabilidade Operacional de Transformadores de Instrumentos para Sistemas de Energia Elétrica

  • Data: 21/06/2018
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  • Os transformadores para instrumentos tais como transformadores de corrente (TCs), transformadores de potencial (TPs) e os transformadores de potencial capacitivo (TPCs) constituem equipamentos fundamentais no sistema de proteção e medição. Estes equipamentos são utilizados para reduzir os altos níveis de correntes e tensões do sistema de transmissão para níveis adequados aos dispositivos de proteção e medição. Os relés de proteção respondem pelos transformadores para instrumentos (TIs). Todavia, os equipamentos que compõem o sistema de proteção e medição não estão imunes a defeitos e falhas. Considerando a grande importância dos transformadores para instrumentos no sistema de transmissão de energia elétrica e que entre os anos de 2015 e 2016 ocorreram casos de explosão em transformadores de corrente e divergências em medições em transformadores de potencial em algumas subestações da Eletronorte - Pará. Em virtude do ocorrido foi proposto um sistema de controle para transformadores de potencial capacitivo, transformadores de potencial indutivo e transformadores de corrente baseado em métodos estatísticos que consideram os seguintes parâmetros: o histórico de manutenção, ensaios elétricos, locais de instalação, as diversas famílias, tempo de operação, ocorrências sistêmicas e tempo de vida útil para estimar grau de confiabilidade operacional destes equipamentos nas subestações da Regional de Transmissão do Pará. Visando a confiabilidade dos diagnósticos para possibilitar a previsão de possível troca de equipamentos que possam vir a falhar e assim permitir a garantia de continuidade dos serviços de transmissão de energia elétrica da área Pará utilizando e aplicando os conceitos de qualidade de energia elétrica, foco em qualidade de serviços.

  • KEVIN EDUARDO LUCAS MARCILLO
  • Performance Evaluation of Robust parametric Control Strategies Applied on Suppression of Oscillations Effects Due to Constant Power Loads in Multi-Converter Buck-Buck Systems

  • Data: 11/06/2018
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  • Multi-converter electronic systems are becoming widely used in many industrial applications; therefore, the stability of the cascaded system is a big concern to real-world power supplies applications. Instability in cascaded systems may occur due to the constant power load (CPL), which is a behavior of the tightly regulated converters. CPLs exhibit incremental negative resistance behavior causing a high risk of instability in interconnected converters; therefore, the mitigation of this problem is an important issue in the multiple-stage switched mode power supply design. Thus, it is important to guarantee stability of the whole system. However, some difficulties remains besides the CPL, e.g., non-linearities due to the inductive element and uncertainties due to imprecision of mathematical models and/or variation of nominal values of the discrete elements that compose the DC/DC buck converter. Aiming to evaluate the performance of the proposed robust methodologies in this work to mitigate the instability problem caused by a CPL, several tests were developed by using an experimental plant and Matlab/Simulink, when the multi-converter buck-buck system is subjected a variation of power reference. The results show the improved performance of the proposed methodologies.

  • NADSON WELKSON PEREIRA DE SOUZA
  • ANÁLISE DE SENSORES PLASMÔNICOS BASEADOS EM NANO ESTRUTURAS ESTRATIFICADAS UTILIZANDO O MÉTODO DAS IMAGENS COMPLEXAS DISCRETAS 

  • Data: 11/05/2018
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  • Nesta tese, apresenta-se a análise teórica de um sensor de ressonância plasmônica de superfície (SPR) acoplado a nanopartículas metálicas. O sensor é considerado na configuração de Emissão Acoplada de Plasmon de Superfície (SPCE), onde as nanopartículas metálicas (ou analitos) são modeladas por dipolos equivalentes localizados acima do sensor. Um conjunto completo de funções diádicas de Green para o campo elétrico é derivado para meios planares, multicamadas e uniaxiais em uma forma computacionalmente eficiente e conveniente para aplicações que utilizem-se do Método das Imagens Complexas Discreta (DCIM) com a utilização do Generalized Pencil of Function Method (GPOF). O princípio da deformação do caminho complexo em um contorno de dois níveis é empregado para expressar uma integral original como uma soma de imagens complexas. Apresenta-se resultados de ressonância plasmônica de superfície, reflexão, campo próximo e distante de sensores planares e descreve-se como estas nanopartículas influenciam na capacidade de aumentar a intensidade de campo próximo e alterar a resposta de sensibilidade destes sensores ópticos. Além disso, para comparação, alguns resultados são calculados por métodos numéricos e experimentais. Os resultados mostram uma boa concordância, o que prova que o DCIM é um método teórico eficiente e poderoso para analisar sensores SPR na configuração SPCE.

  • ALEXANDRE DE SOUZA OLIVEIRA
  • EFEITO DE INTERFERÊNCIA QUÂNTICA NO TRANSPORTE ELETRÔNICO DE DISPOSITIVOS "QUASI-UNIDIMENSIONAIS"

  • Data: 03/05/2018
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  • O estudo de transporte eletrônico em nano-dispositivos tem se mostrado de grande relevância nos últimos anos, desde o trabalho de Aviran e Rartner, baseado nas propriedades de condutividade elétrica em moléculas individuais retificadoras sob ação de um campo elétrico externo. Os polímeros orgânicos conjugados no estado puro apresentam baixa condutividade, mas quando dopados, tratados com agentes oxidantes redutores ou conectados a eletrodos de ouro (Au) e submetidos a um campo elétrico externo, passam a ter um comportamento do tipo metálico, isto é, com alta condutividade em consonância com trabalhos experimentais. Nesta pesquisa foram utilizados dispositivos constituídos de polímeros orgânicos conjugados no estado puro e dopado com cadeias contendo ligações do tipo simples (  e duplas  alternadas entre os carbonos e estes ligados somente a átomos de hidrogênio com eletrodos de ouro (Au) conectados nas extremidades das moléculas individuais. Para este estudo foram utilizados dois tipos de eletrodos: eletrodos em forma de pirâmide e eletrodos planos. Os dispositivos modelos aqui considerados estão divididos em dois grupos e são estruturas quase-1D ou lineares e possuem quantidades ímpares de átomos de carbonos, iniciando com cinco (5) indo até dezenove (19) átomos em sua molécula principal (Grupo 1). De maneira semelhante com quantidades pares de átomos de carbono, a partir de seis (6) até vinte (20) átomos em sua molécula individual (Grupo 2). Estes dispositivos foram submetidos a duas condições: a primeira, em baixas voltagem variando de 0 até 0,1 Volt e em seguida a altas voltagem, de 0 a 1,0 Volt. É importante registrar que para efeito de comparação das curvas de (I-V) e (G-V) entre os resultados de baixa e alta voltagem, tomamos o mesmo intervalo de voltagem, ou seja, de 0 até 0,1 Volts. Para este trabalho, foram analisados os efeitos de interferência quântica destrutiva (IQD), assim como de interferênica quântica construtiva (IQC). Os efeitos de (IQD) são produzidos devido a anti-ressonância na transmitância evidenciadas por estados não acessados observados nos picos de transmissão não permitindo que o transporte ocorra sem apresentar oscilações na curva de condutividade.

  • ROGERIO DIOGNE DE SOUZA E SILVA
  • MODELO PARA TOMADA DE DECISÃO EM PROGRAMAS DE EFICIÊNCIA ENERGÉTICA NO SETOR DE DISTRIBUIÇÃO DE ELETRICIDADE

  • Data: 27/04/2018
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  • O sistema de distribuição de energia elétrica está em constante evolução, com a disseminação de recursos energéticos distribuídos, redes inteligentes e a inclusão de mercados competitivos, em que o uso da eficiência energética como recurso relevante para o planejamento do setor deve ser assegurado por meio de políticas públicas. O Brasil há décadas possuí programas e políticas nessa área, no entanto, os resultados do seu principal programa para a inserção de ações de eficiência energética no sistema de distribuição, têm impacto inferior a programas similares em outros países, somado a isso, há a iminente necessidade de atender os objetivos de redução de emissões propostos pelo país na 21ª Conferência das Partes das Nações Unidas em dezembro de 2015 em Paris. Nesse contexto, a presente tese propõe o desenvolvimento de um modelo não paramétrico, para determinação de indicadores de desempenho e classificação de projetos de eficiência energética. Contribui-se, também, com a avaliação do Programa de Eficiência Energética, por meio de uma metodologia para analisar os projetos, classificar e quantificar as variáveis, resultando em recomendações para o aprimoramento do programa. Utilizou-se uma base de dados de projetos submetidos à ANEEL pelas concessionárias do setor de distribuição de energia elétrica no período de 2008 a 2016.  O modelo foi desenvolvido usando Data Envelopment Analysis (DEA), um método não-paramétrico que utiliza programação linear para calcular as unidades mais eficientes em um determinado conjunto de unidades de tomada de decisão. Os resultados obtidos revelam que o melhor desempenho foi alcançado por projetos nas categorias industrial e de cogeração, no entanto, estes constituem, apenas, 4,24% dos projetos apresentados e 5,28% dos investimentos totais nos últimos oito anos, indicando a necessidade de rever as estratégias regulatórias de eficiência energética. Como uma solução para a seleção de projetos com melhor desempenho, sugerimos atribuir pesos às categorias para otimizar os resultados dos projetos, através de incentivos aos projetos com o melhor desempenho, sem excluir a participação de todos os outros, simplesmente fornecendo objetivos de economia de energia e redução de demanda no horário de ponta compatíveis com as categorias com melhores resultados.

  • JULIO CESAR DA SILVA DOS SANTOS
  • TRANSPORTE ELETRÔNICO EM ALÓTROPOS DE CARBONO ANÁLOGOS AO GRAFENO

  • Data: 20/04/2018
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  • Atualmente, materiais nanoestruturados à base de carbono tornaram-se de grande interesse para a comunidade científica devido às propriedades que estes materiais apresentam na área tecnológica. Entre as mais variadas estruturas derivadas do carbono, o grafeno, uma forma alotrópica do carbono que apresenta estrutura hexagonal bidimensional (2D) formada a partir da hibridação do carbono sp² tem grande destaque com propriedades elétricas, térmicas e ópticas que exibem grandes perspectivas para futuras aplicações tecnológicas. Recentemente, foi proposto teoricamente uma nova forma alotrópica do grafeno, formada por 5-6-7 anéis aromáticos de carbono. Este alótropo 2D com hibridação sp² é energeticamente comparável ao grafeno e mais favorável a outros alótropos de carbono. Neste trabalho, propomos duas estruturas híbridas ou heterojunções formadas por grafeno - phagrafeno - grafeno com bordas ziguezague na extremidade superior e inferior sem (zzG-zzPG-zzG) e com Hidrogênio (zzGNR-zzPGNR-zzGNR) acoplada a eletrodos de grafeno metálico com índices de Hamada (3,3). A heterojunção constituída por Hidrogênio nas extremidades formam nanofitas (ou nanoribbon, NR). Posteriormente, fizemos um estudo das propriedades eletrônicas das heterojunções sem os eletrodos e de transporte eletrônico dos dispositivos com e sem Hidrogênio. Para realizar os cálculos de propriedades eletrônicas e de transporte de elétrons, utilizamos a metodologia DFT e DFT-NEGF no formalismo Landauer-Büttiker, conforme implementado no código SIESTA/TRANSIESTA. Nossos resultados exibem comportamento de isolante topológico forte com gap indireto igual a 0,011eV para zzG-zzPG-zzG em V = 0V e semicondutor de gap indireto igual a 0,025eV para zzGNR-zzPGNR-zzGNR em V = 0V com transição de fase (isolante-metal) para V min = -0,5V. Assim, características variadas de dispositivos eletrônicos para as regiões de polarização direta (V > 0) e reversa (V < 0) nas heterojunções são sugeridas como: (i) zzG-zzPG-zzG para V > 0 exibe quatro regiões correspondendo a resistor (I), FET (II), NDR (III) e chaveador (IV) e para V < 0 exibe cinco regiões correspondendo a resistor (I), NDR (II), limitador-chaveador (III), NDR (IV) e limitador-chaveador (V). (ii) zzGNR-zzPGNR-zzGNR para V > 0 exibe característica de FET e para V < 0 exibe uma NDR com comportamento de diodo túnel.

  • ELIZETE SABINO MARTINS
  • ANÁLISE E DESEMPENHO DE UM ACOPLADOR BASEADO EM CRISTAL FOTÔNICO DOPADO COM ÉRBIO

  • Data: 13/04/2018
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  • Neste trabalho, utilizamos a teoria de guias de ondas em cristais fotônicos para projetar um acoplador baseado nesses guias, com dopagem de Érbio a fim de verificar o desempenho de comutação para os estados barra e cruzado do dispositivo dopado em relação ao não dopado. O acoplador de cristal fotônico dopado com Érbio utiliza a ressonância não linear causada pela excitação dos íons de érbio localizado na fileira central de um acoplador direcional. Tal excitação provoca a transição dos íons de érbio do estado fundamental para o metaestável fazendo a amplificação do sinal quando os fótons absorvem a luz emitida. As simulações ocorreram no software COMSOL Multiphysics®, o qual utiliza o Método dos Elementos Finitos (FEM). Foi realizada uma análise comparativa entre o acoplador direcional de cristal fotônico dopado com érbio e outro não dopado. Verificou-se o desempenho de comutação de ambos a partir da variação das frequências normalizadas e constatou-se que o acoplador dopado conseguiu operar nos estados barra e cruzado com maior espectro de frequência.

  • PAULO DE TARSO CARVALHO DE OLIVEIRA
  • SISTEMA FUZZY COM AUTOCORRELAÇÃO ESTENDIDA APLICADO À PREDIÇÃO DE DEMANDA DE ENERGIA ELÉTRICA

  • Data: 12/04/2018
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  • SISTEMA FUZZY COM AUTOCORRELAÇÃO ESTENDIDA APLICADO À PREDIÇÃO DE DEMANDA DE ENERGIA ELÉTRICA

  • DEYVISON DE PAIVA PENHA
  • REDE NEURAL CONVOLUCIONAL APLICADA À IDENTIFICAÇÃO DE EQUIPAMENTOS RESIDENCIAIS PARA MONITORAMENTO NÃO-INTRUSIVO DE CARGA

  • Data: 03/04/2018
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  • Este trabalho apresenta a proposta de uma nova metodologia para identificação de equipamentos residenciais em sistemas de Monitoramento Não-Intrusivo de cargas. O sistema é baseado em uma Rede Neural Convolucional para classificação dos equipamentos. Como entradas para  o sistema são utilizados dados do sinal transitório de potência obtidos no momento em que um equipamento é ligado em uma residência. A metodologia foi desenvolvida usando dados de um banco de dados público (REED) que apresenta dados coletados a uma baixa frequência (1/3 Hz). Os resultados obtidos na base de dados de testes indicam que o sistema proposto é capaz de realizar a tarefa de identificação, tendo apresentado resultados considerados satisfatórios quando comparados com os resultados já apresentados na literatura para o problema em questão.

  • BRUNO GOMES DUTRA
  • Methods for real-time intention to motion estimation and control of a myoelectric prosthetic hand: a linear, predictive and stochastic approach.

  • Data: 28/03/2018
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  • Muscle signals from electromyography (EMG) are widely used to detect muscle contraction and intention to motion. By using these signals in real time in prosthetic control, a low signal to noise ratio is commonly found. Thus, it is necessary to have recursive methods, robust to noise and efficient algorithms, to generate commands in real time for the robotic actuator. In this research, stochastic system indentification techniques, Kalman filter, sensor fusion and stochastic predictive control techniques were investigated and applied to improve the measurement and processing of electromyographic signals to increase robustness in the control of biomechatronic prostheses. Thus, it is an improved process, less sensitive to noise and with minimal delays and phase lags. In this methodology, a four-stage distribution method is used: (1) features extraction by using an autoregressive model (AR), (2) data fusion with the Kalman filter, (3) motion estimation algorithm, and (4) predictive control with the generalized minimum variance controller applied to a servomechanism. The main objectives were: to enhance the signal-to-noise ratio of EMG signals, to have a low-cost real-time processing man-machine interface, to avoid measurement problems and to minimize energy consumption of the control system. A didactic plant was developed, which is a 4 channel EMG data acquisition and processing system with a servomechanism and its control system coupled in a robotic jaw. Practical tests were conducted with the prototype and the results show that it is possible to continuously estimate the intention of opening and closing movement of the hand and can confirm the good performance of the stochastic controller designed for the control of the electric prosthesis.

  • TIAGO MACHADO WANZELER
  • AVALIAÇÃO DE DESEMPENHO DAS FUNÇÕES DE CONTROLE VOLT-WATT E VOLT-VAR EM INVERSORES FOTOVOLTAICOS

  • Data: 27/03/2018
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  • AVALIAÇÃO DE DESEMPENHO DAS FUNÇÕES DE CONTROLE VOLT-WATT E VOLT-VAR EM INVERSORES FOTOVOLTAICOS

  • EDSON FARIAS DE OLIVEIRA
  • AVALIAÇÃO DA DISTORÇÃO HARMÔNICA TOTAL DE TENSÃO NO PONTO DE ACOPLAMENTO COMUM INDUSTRIAL USANDO O PROCESSO KDD BASEADO EM MEDIÇÃO

  • Data: 27/03/2018
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  • In the last decades, the transformation industry has provided the introduction of increasingly faster and more energy efficient products for residential, commercial and industrial use, however these loads due to their non-linearity have contributed significantly to the increase of distortion levels harmonic of voltage as a result of the current according to the Power Quality indicators of the Brazilian electricity distribution system. The constant increase in the levels of distortions, especially at the point of common coupling, has generated in the current day a lot of concern in the concessionaires and in the consumers of electric power, due to the problems that cause like losses of the quality of electric power in the supply and in the installations of the consumers and this has provided several studies on the subject. In order to contribute to the subject, this thesis proposes a procedure based on the Knowledge Discovery in Database - KDD process to identify the impact loads of harmonic distortions of voltage at the common coupling point. The proposed methodology uses computational intelligence and data mining techniques to analyze the data collected by energy quality meters installed in the main loads and the common coupling point of the consumer and consequently establish the correlation between the harmonic currents of the nonlinear loads with the harmonic distortion at the common coupling point. The proposed process consists in analyzing the loads and the layout of the location where the methodology will be applied, in the choice and installation of the QEE meters and in the application of the complete KDD process, including the procedures for collection, selection, cleaning, integration, transformation and reduction, mining, interpretation, and evaluation of data. In order to contribute, the data mining techniques of Decision Tree and Naïve Bayes were applied and several algorithms were tested for the algorithm with the most significant results for this type of analysis as presented in the results. The results obtained evidenced that the KDD process has applicability in the analysis of the Voltage Total Harmonic Distortion at the Point of Common Coupling and leaves as contribution the complete description of each step of this process, and for this it was compared with different indices of data balancing, training and test and different scenarios in different shifts of analysis and presented good performance allowing their application in other types of consumers and energy distribution companies. It also shows, in the chosen application and using different scenarios, that the most impacting load was the seventh current harmonic of the air conditioning units for the collected data set.

  • IAGO LINS DE MEDEIROS
  • QoE and QoS-aware Handover for Video Transmission in Heterogeneous Vehicular Networks

  • Data: 19/03/2018
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  • Vehicle Ad Hoc Networks (VANETs) offer a wide range of multimedia services ranging from safety and traffic warnings to entertainment and advertising videos. In this context, users can access content through vehicle-to-infrastructure (V2I) communication, which may consider different wireless networks, such as, LTE, Wi-Fi, etc. However, real-time video streaming at a VANET with Quality of Experience (QoE) and Quality of Service (QoS) is a challenging task, due to the high vehicles mobility that causes communication failure with the infrastructure. This master dissertation introduces a QoE- and QoS-aware handover algorithm for heterogeneous VANETs. The proposed algorithm considers the Analytic Hierarchy Process (AHP) to choose the base station that the vehicle must connect based on multiple criteria, namely, signal strength, QoE, QoS.

  • LADISLAV VRBSKY
  • CLUSTERING-DRIVEN EQUIPMENT DEPLOYMENT PLANNER AND ANALYZER FOR WIRELESS NON-MOBILE NETWORKS APPLIED TO SMART GRID SCENARIOS

  • Data: 16/03/2018
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  • THE IMPROVED POWER GRID, KNOWN AS SMART GRID, RELIES ON VARIOUS ADVANCEMENTS, ONE OF THEM BEING THE INTRODUCTION OF BI-DIRECTIONAL COMMUNICATION. IN SOME CASES, DATA EXCHANGED IN THE NETWORK IS OF CRITICAL IMPORTANCE. THE TRANSFERS NEED TO MEET SPECIFIC DELAY LIMITS SET BY THE REGULATORS IN ORDER FOR THE SMART GRID TO FUNCTION PROPERLY. MEETING THESE STANDARDS RESULTS IN MORE EFFICIENT, STABLE AND ENVIRONMENT-FRIENDLY LIFECYCLE OF ENERGY. THIS THESIS PRESENTS A MODEL OF WIRELESS COMMUNICATION IN SMART GRID OR OTHER NETWORK WITH SIMILAR CHARACTERISTICS, SUCH AS PRESENCE OF ONLY NON-MOBILE SUBSCRIBERS OR FIXED COMMUNICATION PATTERNS. THE MODEL USES A CLUSTERING ALGORITHM TO DETERMINE THE OPTIMAL POSITIONS OF TWO TYPES OF NETWORK CELLS TO BE INSTALLED. AFTER, IT CALCULATES THE DELAY FOR EACH NETWORK SUBSCRIBER, TAKING INTO ACCOUNT THE INFLUENCES OF THE SURROUNDING COMMUNICATION. THIS WAY, AN ANALYSIS CAN BE MADE TO OBTAIN THE QUALITY OF SERVICE ACHIEVED BY A SPECIFIC NETWORK SETUP IN A SPECIFIC SCENARIO. THE RESULTS SHOW, THAT IT IS POSSIBLE TO DEPLOY WIMAX-ENABLED EQUIPMENT IN A SMART GRID NETWORK WITH THE WORST CASE OF 97% TO 100% OF MESSAGES DELIVERED WITHIN THE MAXIMUM DELAY. ALSO, THE THESIS EXPLORES A RESTRICTED COMMUNICATION MODE THAT CAN TEMPORARILY SUSPEND THE TRANSFERENCES OF NON-CRITICAL DATA. THE RESTRICTED MODE DELIVERS THE CRITICAL DATA WITHIN THE MAXIMUM DELAY WITH THE SUCCESS RATE OF 100% IN ALL INSTANCES. MORE IMPORTANTLY, THE MODEL PRESENTED IN THIS THESIS IS CUSTOMIZABLE AND IS MADE PUBLICLY AVAILABLE ONLINE AS AN OPEN-SOURCE PROJECT, SO THAT ANYONE, INCLUDING RESEARCHERS, OR PRIVATE AND PUBLIC COMPANIES, CAN TAKE ADVANTAGE OF IT.

  • DANIEL DA SILVA SOUZA
  • Uma Análise Técnico-Econômica para Implantação de Arquiteturas Centralizadas de Redes de Telefonia Móveis.

  • Data: 06/03/2018
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  • Diante dos desafios propostos pela quinta geração de redes móveis, a arquitetura Centralizada de Redes de Acesso (C-RAN) vem ganhando espaço por oferecer suporte à redes ultra-densas de alta capacidade de próxima geração. Esta dissertação propõe uma metodologia de análise de custo para C-RAN, abrangendo as despesas de implantação e de operação. O modelo proposto é utilizado em um estudo de caso em que o custo total de implementação e operação das arquiteturas distribuídas e centralizadas são comparados. Os resultados apontam uma economia nos cenários centralizados e destacam os aspectos econômicos mais relevantes no planejamento da C-RAN.

  • HUGO LEONARDO MELO DOS SANTOS
  • A MULTI-TIER FOG ARCHITECTURE FOR VIDEO ON DEMAND STREAMING

  • Data: 05/03/2018
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  • Users are changing their traditional communication paradigm based on voice calls or text messages to real-time or on demand video services consumed on mobile devices. In this sense, the transmission of video content considering an adequate Quality of Experience (QoE) in mobile wireless networking infrastructures is a critical issue in both academic and industrial communities. Furthermore, video on demand have a growing consumption over Internet requiring higher bandwidth and lower latency. In this context, a fog computing paradigm can enhance the user experience in wireless networks. Fog computing for video on demand streaming can improve QoE by both video caching and adaptation schemes. However, it is important to evaluate the performance of downloading the videos with different codec configuration and cached closer to the user to measure the gain from the user perspective. We designed a multi-tier fog computing architecture with three levels located in the cloud, nearer the edge and in mobile devices. We evaluated the performance of downloading the video from multiple tier located in distinct geographical with a multimedia application. We assessed in an experimental environment with idle and congested network of streamed videos coded into H.264 and H.265 with three bitrates in a scenario deployed in the FIBRE testbed. We collected QoE metrics, playback start time, freeze times, QoS metric, round-time trip, and energy consumption to analyze the gains for each video configuration. These results showed an important understanding about cache, codec and bitrate schemes in multimedia networking scenarios.

  • TARCISIO CARLOS FARIAS PINHEIRO
  • CONSTRAINED MULTIVARIABLE MPC CONTROL USING LAGUERRE FUNCTIONS

  • Data: 01/03/2018
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  • This work presents a constrained multivariable model predictive controller using Laguerre Functions. This controller uses a set of orthonormal Laguerre networks for representation of the control trajectory within a control horizon. In order to demonstrate the advantages of applying this type of controller in MIMO (Multiple-Input and Multiple-Output) systems, the Laguerre Functions Functions are used to decrease the computational load used to calculate the optimal control. In addition, It improves the compromise between control signal viability and closed-loop performance of the system. The Laguerre Functions are also used in conjunction with Hildreth's Quadratic Programming to find the optimal solution for the case where the control signal is constrained. The proposed controller presents advantages when compared to the classical model predictive control approach, where forward shift operators are used to predict the future trajectory of the control signal, leading to unsatisfactory solutions and a high computational load for cases where the control signal demands a long prediction horizon and a high closed-loop performance.It is also reported the practical testes with a robotic manipulator configured as a MIMO system with three inputs and three outputs and tests simulated with the Wood and Berry binary distillation column which is a MIMO system with two inputs and two outputs, also containing transport time delays. The tests aim to compare the controller results presented with the traditional predictive control approach and thereby demonstrate the advantages of the method using the Laguerre functions and their efficiency for MIMO systems.

  • JORGE DE ALMEIDA BRITO JUNIOR
  • SOLUÇÃO PARA O DESPACHO ECONÔMICO AMBIENTAL DE UM SISTEMA DE GERAÇÃO TÉRMICA POR RECOZIMENTO SIMULADO

  • Data: 27/02/2018
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  • Nos últimos anos, tornaram-se crescentes as preocupações da população e dos governos com a proteção do meio ambiente. Ao mesmo tempo, a utilização de combustíveis fósseis para a produção de energia elétrica ainda é elevada, devido a disponibilidade deste insumo energético e a tecnologia consolidada das usinas térmicas. Em função deste contexto, vem se tornando cada vez mais comum a adoção de metodologias para a otimização das usinas, não só em função co custo de combustível, mas também das emissões que as usinas geram, o que vem trazendo um impacto positivo na redução da poluição ambiental, para geração de energia elétrica junto a sistemas térmicos baseados em combustíveis fósseis. Por outro lado, este processo estabelece a necessidade de pesquisas no campo do planejamento energético, baseadas normalmente na aplicação de métodos de otimização que levem em consideração dois objetivos integrados. A partir desta realidade, o presente trabalho tem como proposição o despacho de carga econômico e ambiental (DEA) de um sistema de geração térmico com as características estabelecidas previamente. Para o desenvolvimento da otimização proposta será utilizada a ferramenta computacional de otimização de recozimento simulado. A ferramenta será utilizada com duas funções objetivo, a de custo e de emissões para ser encontrado o resultado ótimo e também levando em consideração o desligamento dos motores menos eficientes, garantido a redução dos custos financeiros e da poluição.

  • HUGO ALEXANDRE OLIVEIRA DA CRUZ
  • METHODOLOGY OF PREDICTION OF LOSS OF PROPAGATION AND VIDEO QUALITY IN INDOOR WIRELESS NETWORKS BY ARTIFICIAL NEURAL NETWORKS

     

  • Data: 27/02/2018
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  • This dissertation presents a methodology, which aims to assist the planning of indoor wireless network systems, which require prior knowledge of the environment in which they will be deployed. Thus, a rigorous signal analysis is necessary by means of an empirical statistical approach, which takes into account some factors that influence the propagation of the indoor signal: architecture of the buildings; arrangement of furniture inside the compartments; numbers of walls and floors of various materials, and the spread of radio waves. The methodology adopted is based on measurements with a cross-layer approach, which demonstrates the impact of the physical layer in relation to the application layer, in order to predict the behavior of the Quality of Experience (QoE) metric, called Peak signal- to-noise ratio (PSNR), in 4K video streams on 802.11ac wireless networks in the indoor environment. In order to do so, measurements were performed, which demonstrate how the signal / video degrades in the studied environment. It is possible to model this degradation by means of a computational intelligence technique, called Artificial Neural Networks (RNA), in which input parameters are inserted as , for example, the distance from the transmitter to the receiver and the number of walls crossed in order to predict loss of propagation and loss of PSNR.

  • MILTON FONSECA JUNIOR
  • PRÉ-DESPACHO DE CARGA EM USINAS TERMOELÉTRICAS CONSIDERANDO A GESTÃO DA MANUTENÇÃO VIA LÓGICA FUZZY

  • Data: 27/02/2018
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  • Pré-despacho de carga, Gerenciamento de Manutenção, Geradores Elétricos, TPM, Usinas Termoelétricas, Lógica Fuzzy.

  • MARCEL AUGUSTO ALVARENGA VIEGAS
  • AVALIAÇÃO DO IMPACTO ECONÔMICO DA CONEXÃO DE VEÍCULOS ELÉTRICOS E DA GERAÇÃO EÓLICA EM REDES INTELIGENTES DE ENERGIA

  • Data: 26/02/2018
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  • AVALIAÇÃO DO IMPACTO ECONÔMICO DA CONEXÃO DE VEÍCULOS ELÉTRICOS E DA GERAÇÃO EÓLICA EM REDES INTELIGENTES DE ENERGIA

  • DENNER FELIPE SILVA FERREIRA
  • TRANSPORTE ELETRÔNICO EM SISTEMAS HÍBRIDOS DE CARBONO E ELETRODOS DE FE E FE/AU

  • Data: 23/02/2018
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  • TRANSPORTE ELETRÔNICO EM SISTEMAS HÍBRIDOS DE CARBONO E ELETRODOS DE FE E FE/AU

  • WANESSA TAMIRIS DE SOUZA PINHEIRO
  • ANÁLISE DO IMPACTO DE GERADORES FOTOVOLTÁICOS NA ESTABILIDADE TRANSITÓRIA DE GERADORES SÍNCRONOS DISTRIBUÍDOS

  • Data: 19/02/2018
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  • Essa dissertação de mestrado apresenta uma análise de dois modelos de controle de inversores para análise da estabilidade transitória com a inserção da geração fotovoltaica na rede de distribuição. É proposto também uma análise da influência tanto negativa quanto positiva causada pelos modos de controle desses inversores na estabilidade da máquina síncrona. Uma solução também a ser investigada é o uso do modo de controle de potência reativa dos geradores fotovoltaicos via inversor, e que posso aliviar a demanda de reativo dos geradores síncronos distribuídos interligados no mesmo sistema elétrico, reduzindo assim, a possibilidade de gerar uma condição de instabilidade de tensão, após uma grande perturbação, ou a ocorrência de contingências no sistema elétrico que possam afetar redes elétricas fracas, ou sobrecarregadas e com grande inserção de geradores fotovoltaicos. As análises dos modelos de controle são realizadas por meio de simulações no domínio do tempo através da ferramenta computacional ANATEM.

  • RENAN LANDAU PAIVA DE MEDEIROS
  • INVESTIGAÇÃO DE ESTRATÉGIAS DE CONTROLE ROBUSTO MULTIVARIÁVEL DESCENTRALIZADO APLICADAS À MELHORIA DO DESEMPENHO DE UM CONVERSOR DE POTÊNCIA CC/CC DO TIPO BUCK COM ESTRUTURA SINGLE INDUCTOR MULTIPLE OUTPUT

  • Data: 05/02/2018
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  • MEDEIROS, R. L. P. Experimental Evaluation of decentralized robust multivariable control strategies applied for performance enhancement of a DC-DC Buck type power converter with Single Inductor Multiple Output structure. 2018. Thesis (Doctor in Electrical Engineering) – Post Graduation Program of Electrical Engineering/ UFPA, Belém – PA, Brazil.
    The DC/DC power converter systems are important devices to use in several applications in many sectors of the society. For this reason, several DC/DC converter topologies are developed to improve the performance of devices, aiming at reducing losses and improving the converter energy quality. However, such improvements should assess the control strategies that enable the correct functioning of the power converters. This works covers experimental assessment of the design of robust decentralized multivariable controller applied to a specific topology of the multivariable step-down power converter, where a single inductor element is shared by multiples outputs. Furthermore, it is important to ensure the system stability, as well as the multiple
    outputs regulations, however some difficulties remains, e.g., hard coupling between system’s outputs, non-linearities due to the inductive element and uncertainties due to imprecision of mathematical models and/or variation of nominal values of the discrete elements that compose the DC/DC converter. Aiming to assess the performance of the proposed design methodology for a multivariable robust controller, to perform
    experiments of parametric variations on the DC/DC power converter, it is developed several experimental tests and simulations using the Matlab. The results show the improved performance of the proposed methodology

  • VANESSA MENEZES RAMOS
  • CONTROLE DE FREQUÊNCIA DE GERAÇÃO FOTOVOLTAICA CONSIDERANDO INÉRCIA VIRTUAL

  • Data: 30/01/2018
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  • O aumento das fontes de energia renováveis resulta em uma necessidade urgente de avaliar seu impacto na estabilidade da rede, pois tanto a resposta inercial quanto o controle primário e secundário são altamente influenciados pela integração destas fontes. O objetivo principal deste trabalho foi implementar um modelo a pequenos sinais lenearizado de rastreamento para seguir um sinal de comando, que muda de acordo com o desvio de frequência da rede elétrica, no sentido de avaliar a estabilidade de um sistema composto por unidades convencionais e renováveis de energia elétrica, no sentido de avaliar a estabilidade de um sistema composto por unidades convencionais e renováveis é mais notável em situações de baixa carga, pois a integração de tais fontes poderá ocasionar a desativação de usinas tradicionais, as quais serão substituídas, podendo diminuir assim consideravelmente a inércia total da rede. No caso da fonte renovável baseada em sistemas fotvoltaicos, a resposta da rede é reduzida somente durante momentos de alta carga (maior inpercia inicial).

  • WILSON ROGERIO SOARES E SILVA
  • METODOLOGIA DE MONITORAMENTO DE EDPIDEMIAS NA AMAZÔNIA: UM ABORDAGEM BASEADA EM REDES NEURAIS ARTIFICIAIS

  • Data: 26/01/2018
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  • A dengue é uma doença infecciosa viral presente em mais de 100 países no mundo. Em páises subdesenvolvidos como o Brasil, tal patologia ganha contornos dramáticos, pois adicionam-se a componente de péssimas condições de saneamento básico. Esse cenário é amplificado quando é relacionado à Amazônia e suas condições geográficas e climáticas. Segundo dados disponilizados pelo Ministério da Saúde (2010), dos 409.073 casos notificados na região Norte, 106.433 ocorreram no Estado do Pará. Esse trabalho propõe uma metodologia para prever epidemias, usando Redes Neurais Artificiais, com estudo de caso  de previsão de casos de dengue na Amazônia. Para tanto, desenvolveu-se um sistema que usa base de dados públicos de casos da doença, de ocorrência semanal, de quatro municípios: Belém, Parauapebas, Altamira e Santarém. Em adição, implementa-se um módulo de emissão de alertas, visando à detecção de um aumento repentino de novos casos da doença, contribuindo para tomada de decisão dos órgãos de saúde pública e sua respectivas ações de controle das epidemias nos municípios em estudo. Os resultados demonstraram que o modelo de Redes neurais Artificiais, para o cenário em voga, obteve um bom desempenho na prvisão epidemiológica, alcançando acurária satisfatória.

  • LUÍS AUGUSTO MESQUITA DE CASTRO
  • DESIGN OF POWER SYSTEM STABILIZERS USING MINIMUM VARIANCE CONTROL IN THE STATE SPACE.

  • Data: 24/01/2018
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  • The use of power system stabilizers is essential for reliable operation of large electrical systems. Most stabilizers in operation are designed using classical control techniques based on linearized power systems models. Although this type of stabilizer presents satisfactory performance for the damping of oscillations inherent in the power system, many studies show that the use of adaptive and intelligent control techniques for the synthesis of the control law in
    these stabilizers can produce even better results.
    In this work it is investigated the performance of a predictive control strategy, of the minimum variance control type in the state space, applied to the damping of electromechanical oscillations in interconnected power systems. In the proposed strategy, a linear (deterministic or stochastic) model capable of adequately representing the plant dynamics is used and, from such a model, a state space representation of the system is obtained. The synthesized control law is applied in the nonlinear system, so that the controller can maintain its characteristics of robustness and performance for the entire range of operation, increasing the stability limits of the power system.

  • ADONIS FERREIRA RAIOL LEAL
  • OTIMIZAÇÃO DA DETECÇÃO DE FORMAS DE ONDA DE CAMPOS ELETROMAGNÉTICOS EMITIDOS POR DESCARGAS ATMOSFÉRICAS

  • Data: 23/01/2018
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  • Este trabalho propõe maneiras de otimizar a detecção e registro de formas de onda de campos elétricos radiados por descargas atmosféricas. Como resultado das técnicas de otimização desenvolvidas nesta Tese, é apresentado o "Sistema de detecção e armazenamento de formas de onda de raios" ou "Lightning Detection and Waverform Storage System - (LDWSS)", como um dispositivo otimizado para o registro de campos eletromagnéticos gerados por raios. Os principais pontos aprimorados foram: custo do dispositivo; ampliação do range dinâmico de detecção; desenvolvimento de um sistema mo´vel; possibilidade de detecção multibanda e; calibração para inferir de forma remota a corrente de pico dos raios detectados. O sistema desenvolvido foi validado, a partir de comparações com dados de raio trigado, no Centro Internacional para Pesquisa e Teste com Raios (Internacional Center for Lightning Research and Testing - ICLRT), dados da Rede Nacional Norte Americana de Detecção de Raios (National Lightning Detection Network - NLDN) e dados do Observatório de Raios em Gainesville (Lightning Observatory in Gainesville - LOG). A principal aplicação do sistema é na investigação da física e dos efeitos das descargas atmosféricas, principalmente na região Amazônica. Como resultado da utilização do sistema obteve-se: melhor entendimento sobre as descargas intranuvem do tipo Compact Intracloud Discharge - CID; as características da altura da ionosfera calculada utilizando formas de onda de raios intranuvem e nuvem-solo. a criação de um banco de dados contendo mais de 8 mil formas de onda do campo elétrico de diferentes tipos de raios e; a primeira estação de registro contínuo de formas de onda de campo elétrico devido a raios na Amazônia, localizada no CENSIPAM regional Belém.

  • ANDREZA CARDOSO FERREIRA
  • MODELAGEM E SIMULAÇÃO DA OPERAÇÃO DE SISTEMAS DE GERAÇÃO COM FONTES RENOVÁVEIS DE ENERGIA SUPRINDO MINIRREDE DE DISTRIBUIÇÃO

  • Data: 19/01/2018
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  • MODELAGEM E SIMULAÇÃO DA OPERAÇÃO DE SISTEMAS DE GERAÇÃO COM FONTES RENOVÁVEIS DE ENERGIA SUPRINDO MINIRREDE DE DISTRIBUIÇÃO

  • JORGE HENRIQUE COSTA ANGELIM
  • GERENCIAMENTO ÓTIMO DE SISTEMA DE ARMAZENAMENTO DE ENERGIA UTILIZANDO RECOZIMENTO SIMULADO

  • Data: 18/01/2018
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  • GERENCIAMENTO ÓTIMO DE SISTEMA DE ARMAZENAMENTO DE ENERGIA UTILIZANDO RECOZIMENTO SIMULADO

2017
Descrição
  • ANA CAROLINA QUINTAO SIRAVENHA
  • AVALIAÇÃO DE TÉCNICA SEMI-SUPERVISIONADA DE ANÁLISE DE VETOR COMPRIMIDO (C2VA) EM IMAGENS DE SATÉLITES PARA DETECÇÃO DE MUDANÇAS DE USO E COBERTURA DA TERRA

  • Data: 15/12/2017
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  • Remote sensing image databases and Geographical Information System have the potential to act as accurate tools for environmental monitoring. Carajas Mountains are an important mineral deposit in Brazil and as environmental laws protect a great portion of this region, they have been at the core of conflicts involving human and nature interests. The biggest mining project in Brazil is active in this region (Carajas project) and this analysis aims at identifying the environmental impact caused directly or indirectly by this activity using state of the art methods. This study collects information of land-use and land-coverage from an area larger than 111 000km2 including five municipalities, aiming at observing the landscape intervention from a big scale perspective as a counterpoint to other studies which are focused on a particular region, such as watersheds. Therefore, employing the resultant products of the multi-spectral approach called Compressed Change Vector Analysis, this work analyses both the environmental changes in each studied municipality of the Carajas Mountains and the environmental counterpart of the company that runs the mining activity. The results show that in general the vegetative coverage was replaced by pasture lands, which in turn were replaced by urban occupations. The comparison with official statistics indicates good accuracy of the present study in the estimation of vegetative cover, although the authors claim that the official methodology can produce inaccurate percentages, probably due to the decrease of spatial resolution from 30 to 60 meters, which affects the minimum size of the identified polygons. The presence of environmentally protected areas has prevented the increase of deforestation in the mountains, in which the observed change rates were at least 15% lower than non-protected regions.

  • ALEXSANDER NÚÑEZ
  • EXTENSÃO DO PLANO DE CONTROLE SEM FIO PARA AMBIENTES EXPERIMENTAIS OUTDOOR

  • Data: 14/12/2017
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  • O uso de ambientes experimentais sem fio é uma poderosa ferramenta para validação de pesquisas em Internet do Futuro e testes de produtos e serviços. Estados Unidos, Europa, Japão, Brasil, entre outros, através de iniciativas como FIRE, GENI, AKARI e FIBRE, já disponibilizam tais ambientes para os pesquisadores. No entanto, a topologia desses ambientes, no contexto sem fio e outdoor, ainda é muito limitada em função da necessidade   de infraestrutura   cabeada   para   o   controle   dos dispositivos. Desta forma, este artigo apresenta uma proposta de plano de controle sem fio para esses ambientes experimentais outdoor, permitindo a independência de infraestrutura cabeada.

  • JOSE HENRIQUE DIAS ONAKA
  • FERRAMENTAS DE APOIO À TOMADA DE DECISÃO AO PROBLEMA DE ALOCAÇÃO ÓTIMA DE BANCOS DE CAPACITORES EM REDES DE DISTRIBUIÇÃO DE ENERGIA CONSIDERANDO CARGAS NÃO LINEARES

  • Data: 14/12/2017
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  • FERRAMENTAS DE APOIO À TOMADA DE DECISÃO AO PROBLEMA DE ALOCAÇÃO ÓTIMA DE BANCOS DE CAPACITORES EM REDES DE DISTRIBUIÇÃO DE ENERGIA CONSIDERANDO CARGAS NÃO LINEARES

  • DIEGO DE AZEVEDO GOMES
  • MODELLING AND MITIGATION OF ALIEN CROSSTALK FOR DSL SYSTEMS

  • Data: 11/12/2017
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  • G.fast is the most recent ITU-T standard for copper-based transmission, which targets copper topologies with short distances and adopts a bandwidth of 106 MHz extensible to 212 MHz. In several scenarios, G.fast systems will be composed by or coexist with uncoordinated (or alien) lines, which are sources of strong crosstalk, because are not part of the vectored group. This document presents a formulation to explain the performance of the methods according to the number of the alien lines in the environment, the mechanism that defines the interference correlation and an alien mitigation method for downstream DSL transmission impaired by multiple interferers. Simulation results show that alien crosstalk mitigation methods can indeed improve the performance of G.fast systems, but under specific conditions. We have contrasted these situations and we provide guidelines about the feasibility of the crosstalk mitigation technique in scenarios with distinct alien lines. Additionally, the proposed method shows promising results when compared with literature methods. As support for the simulations, we also present a set of alien crosstalk measurements.

  • WASHINGTON CESAR BRAGA DE SOUSA
  • METODOLOGIAS  DE DISCRETIZAÇÃO ESPACIAL SEM MALHA BASEADAS NOS POTENCIAIS DE COULOMB E LENNARD-JONES PARA O MÉTODO RADIAL DE INTERPOLAÇÃO POR PONTOS (RPIM) APLICADAS PARA SOLUÇÃO NUMÉRICA DAS EQUAÇÕES DE MAXWELL.

  • Data: 04/12/2017
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  • Neste trabalho, novos métodos de interação de partículas, baseados nos potenciais de Coulomb e de Lennard-Jones (dinâmica molecular), foram desenvolvidos e implementados computacionalmente para a geração de discretização espacial meshless.
    As novas metodologia, denominadas CLDM, ECGGM e LJDM, empregam versões adaptadas das equações de força vetorial de Coulomb e de Lennard-Jones para a obtenção de uma distribuição equilibrada de nós no espaço (estado de equilíbrio), de tal maneira a alcançar alta qualidade da discretização do espaço e de estruturas complexas. Para este objetivo, uma nova métrica de qualidade é introduzida. Os métodos RPIM (Radial Point Interpolation Method) e UPML (Uniaxial Perfectlly Matched Layers) são usados para resolver equações de Maxwell no domínio do tempo para problemas 2D (modo TMZ). Os métodos propostos são aplicados a problemas de espalhamento eletromagnético, baseados em cilindros metálicos circulares, triangulares e elípticos. Os resultados obtidos estão em conformidade com soluções analíticas.

  • CARLOS PATRICK ALVES DA SILVA
  • UMA METODOLOGIA PARA AFERIÇÃO DA ACURÁCIA DE MODELOS DE PROJEÇÃO DE LONGO PRAZO PARA A PREVIDÊNCIA SOCIAL NO BRASIL

  • Data: 01/12/2017
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  • As projeções de longo prazo de resultado previdenciário publicadas na Lei de Diretrizes Orçamentárias (LDO) são recorrentemente usadas como subsídios para as propostas oficiais de reforma da previdência social no Brasil. Entretanto, a confiabilidade dos resultados é incerta, já que não há, da parte do governo ou de outros, qualquer avaliação sistemática das projeções que tenha sido publicada. Este trabalho apresenta um estudo dos instrumentos utilizados pelo governo brasileiro para projetar resultados atuariais de longo prazo. Nossa análise empírica demonstra que as projeções do governo são sistematicamente enviesadas no curto prazo e apresentam erroso tão significativos no longo prazo que os tornam desprovidos de significado econômico. Demonstramos também os problemas associados ao cálculo de intervalos de confiança nas projeções de resultados previdenciários. Por fim, apresentamos um software de domínio público que corrige todos os problemas apontados e permite que qualquer cidadão avalie diferentes propostas de reforma da previdência.

  • ELTON RAFAEL ALVES
  • PREVISÃO DE RAIOS UTILIZANDO TÉCNICAS DE INTELIGÊNCIA COMPUTACIONAL E DADOS DE SONDAGEM ATMOSFÉRICA POR SATÉLITE

  • Data: 30/11/2017
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  • PREVISÃO DE RAIOS UTILIZANDO TÉCNICAS DE INTELIGÊNCIA COMPUTACIONAL E DADOS DE SONDAGEM ATMOSFÉRICA POR SATÉLITE

  • LUIZ CORTINHAS FERREIRA NETO
  • ABORDAGEM DE LEITURA DE TEXTO EM IMAGENS PROVENIENTES DE REDES SOCIAIS PARA GANHO EM DISPONIBILIDADE DE DADOS

  • Data: 19/10/2017
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  • Este trabalho tem como objetivo propor uma mudança metodológica no processo de análise de sentimentos em redes sociais, baseado na inclusão de texto obtido de imagens provenientes das próprias redes socias. O processo de análise de sentimento é de fundamental importância para a inteligência de mercado, a análise de redes sociais, a análise de produtos, para os procesos de CRM e SCRM, uma vez que estes são tendências de mercado utilizadas por grande empresas, que acabam portanto, auxiliando na atração de incentivos financeiros e motivando a pesquisa. O modelo proposto neste trabalho tem sua importância fundamentada na disponibilidade de dados, que tem se tornado cada vez mais restrita, graças a utilização de API's, que são as interfaces de gerenciamentos de acesso aos dados onde, de várias maneiras diferentes, cada rede social limita a consulta de dados, seja por tipo de dado, quantidade coletada ou janela de coleta. Esta pesquisa tem a pretensão de provar, por eio de estudos de caso, que existe ganho de dado e de informação para o processo de análise de sentimentos ao incluir dados textuais proveniente de imagens.

  • FLAVIA AYANA NASCIMENTO DE LIMA
  • AGRUPAMENTO DE FORNOS DE REDUÇÃO DE ALUMÍNIO UTILIZANDO ALGORITMOS AFFINITY PROPAGATION, MAPA AUTO-ORGANIZÁVEL DE KOHONEN (SOM), FUZZY C-MEANS E K-MEANS

  • Data: 11/10/2017
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  • AGRUPAMENTO DE FORNOS DE REDUÇÃO DE ALUMÍNIO UTILIZANDO ALGORITMOS AFFINITY PROPAGATION, MAPA AUTO-ORGANIZÁVEL DE KOHONEN (SOM), FUZZY C-MEANS E K-MEANS

  • FERNANDA REGINA SMITH NEVES CORREA
  • MAPEAMENTO DE BITS PARA ADAPTAÇÃO RÁPIDA A VARIAÇÕES DE CANAL DE SISTEMAS QAM CODIFICADO COM LDPC

  • Data: 29/09/2017
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  • Os códigos com matriz de verificação de paridade de baixa densidade (LDPC), têm sido adotados como estratégia de correção de erros em diversos padrões de sistemas de comunicação, como por exemplo, no sistema G.hn (padrão que unifica as redes domésticas). Em sistemas QAM, é sabido que os bits individuais são normalmente associados a diferentes sub-canais. Em sistemas QAM codificados com LDPC, como o G.hn, o mapeamento de bits codificados para os diferentes sub-canais garante uma melhoria no desempenho geral do sistema. Essa técnica pode se aproveitar da propriedade de proteção desigual de erro (UEP) inerente aos códigos LDPC irregulares e também do fato de os sub-canais terem diferentes qualidades (SNR média ou capacidade) para mapear propriamente os bits codificados. Nesse sentido, esta Tese apresenta uma nova técnica de mapear propriamente os bits codificados. Nesse sentido, esta Tese apresenta uma nova técnica de mapeamento de bits que visa melhorar o desempenho de sistemas QAM codificados com LDPC. O mapeamento de bits proposto baseia-se na suposição de que bits transmitidos em sub-canais "bons", com ganhos maiores, ajudam bits transmitidos em sub-canais "ruins". Isto é possível através da imposição e proibição de algumas conexões entre nós de variável e nós de paridade no grafo de Tanner, semelhantes aos chamados códigos Root-LDPC. O mapeamento de bits proposto é aplicado ao sistema G.hn, com os códigos QC-LDPC e modulação QAM. Verifica-se que, na presença de variações do canal, o sistema pode, adaptativamente, aplicar um novo mapeamento de bits sem a necessidade de recorrer a uma otimização complexa. Os resultados das simulações mostram que a estratégia de mapeamento de bits melhora o desempenho do sistema, tanto para o modo de transmissão single-carrier quanto para o modo OFDM.

  • ALINE AYAKO OHASHI
  • IMPACTO DE NÃO-UNIFORMIDADES EM CABOS DE PARES TRANÇADOS NA TRANSMISSÃO EM MODO FANTASMA

  • Data: 25/09/2017
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  • A demanda de tráfego para sistemas de comunicação móveis são esperadas aumentar drasticamente nos próximos anos. A nova geração de comunicação wireless denominada 5G é esperada alcançar tais demandas, permitindo amplo alcance de novas aplicações. Um ponto chave no sucesso de futuras redes 5G é a adoção de souções fronthaul/backhaul. Tradicionalmente, enlaces ópticos e de microondas são soluções preferíveis. Entretanto, o cobre ainda é a solução viável para fronthaul 5G em certas situações, principalmente devido ao seu custo reduzido e as aplicações de técnicas que aumentam a performance do cobre como o modo fantasma. Tal técnica adiciona canais extras sobre os canais diferencias comuns para o mesmo sistema de cobre, aumentando a taxa de dados agregada. Como em sistemas de cobre comuns, o vazamento de sinal entre os canais, chamando crosstalk, é a principal causa de degradação da performance para canais fantasma. Idealmente, não existe vazamento de canal diferencial para o canal fantasma e vice-versa. Entretanto, cabos de cobre possuem não-uniformidades que são fonte de vazamento de sinal entre os pares, especialmente em altas frequencias. Não é completamente conhecido como as não-uniformidades nos cabos afetam o crosstalk do modo de transmissão diferencial para o fantasma e vice-versa. Neste trabalho nós estudamos o efeito de não-uniformidades em cabos na atenuação de transmissões fantasma e diferencial bem como o crosstalk entre eles. Nós mostramos como não-uniformidades na geometria dos pares podem afetar a taxa de dados alcançadas para esses modos em altas frequencias requeridas pelo 5G.

  • WERBESTON DOUGLAS DE OLIVEIRA
  • AVALIAÇÃO DA SEGURANÇA DE SISTEMAS DE POTÊNCIA PARA MÚLTIPLAS CONTINGÊNCIAS USANDO ÁRVORE DE DECISÃO MULTI-CAMINHOS

  • Data: 15/09/2017
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  • AVALIAÇÃO DA SEGURANÇA DE SISTEMAS DE POTÊNCIA PARA MÚLTIPLAS CONTINGÊNCIAS USANDO ÁRVORE DE DECISÃO MULTI-CAMINHOS

  • DIEGO DA COSTA DO COUTO
  • MINERAÇÃO DE DADOS EDUCACIONAIS APLICADA À BUSCA DE PERFIS DE ALUNOS EM CASOS DE EVASÃO OU RETENÇÃO: UMA ABORDAGEM ATRAVÉS DE REDES BAYESIANAS

  • Data: 12/09/2017
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  • Este trabalho investiga os perfis de alunos de cursos da graduação da Universidade Federal do Pará propensos a dois problemas enfrentados em diversas universidades brasileiras denominados evasão e retenção. Estas problemáticas estimularam o estudo de metodologias que detectassem padrões que suscitam a extrapolação ou o fim prematuro dos estudos. A ferramenta elegida a este fim, a Rede Bayesiana é poderosa ao propiciar raciocínio sobre incertezas, especialmente em diagnósticos de causas e efeitos tendo como pressuposto o relacionamento das variáveis e suas probabilidades de ocorrências conjuntas e marginais. Outro aspecto inerente a estrutura das Redes Bayesianas diz respeito à compreensibilidade da representação e dos resultados, os quais geram subsídios voltados a especialistas e usuários inseridos no domínio. Considerando tais colocações, essas potencialidades da metodologia em questão fortaleceram a sua aplicação nesta pesquisa. Dessa forma, registros acadêmicos contendo dezenas de milhares de amostras oriundas de alunos imersos em ambientes de ensino presencial pertencentes aos alunos de graduação ingressantes na Universidade Federal do Pará até o ano de 2016 foram submetidos ao processo de Descoberta de Conhecimento em Base de Dados, especificamente na etapa de Mineração de Dados os padrões desejados foram extraídos valendo-se da tarefa de classificação. Em adição, realizou-se na etapa de Mineração de Dados várias análises de desempenhos da Rede Bayesiana junto a outros algoritmos clássicos do aprendizado supervisionado, e aquela revelou a sua grande acurácia e eficiência, ressaindo dentre as melhores soluções encontradas, isto posto o seu uso foi certificado sobre a base de dados selecionada. Em três estudos de casos avaliados, os resultados indicaram a qualidade do classificador baseado em Redes Bayesianas que apresentou acurácia superior a 82%, condição que legitima a sua utilidade no domínio pesquisado. Assim, os resultados atingidos foram satisfatórios e apontaram fortes influências de algumas variáveis à propensão da evasão ou retenção.

  • MARKOS PAULO CARDOSO
  • ESTUDO DE FIBRAS POROSAS COM INCLUSÕES METÁLICAS PARA GUIAMENTO EM THZ

  • Data: 08/09/2017
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  • O guiamento de ondas THz tem se mostrado de grande importância na melhoria da performance das configurações de espectroscopia, imagem e sensoriamento. Um dos maiores desafios na concepção dessas estruturas é a mitigação das altas perdas apresentadas pela mídia dielétrica na faixa espectral THz (0.1 até THz). Este trabalho realiza a modelagem analítica e numérica de fibras porosas com inclusões de ouro para guiamento em THz. O design dessas interfaces metal-dielétricas é capaz de confinar as ondas THz nas regiões de ar da fibra porosa através da excitação de plasmons de superfície, modos que resultam da interação ressonante entre a radiação eletromagnética incidente e a oscilação coletiva de elétrons livres na superfície metálica. É evidenciado que a partir de um design adequado da camada de ouro, as perdas efetivas podem ser reduzidas e uma dispersão cromáticas zero pode ser alcançada como resultado do acoplamento entre os modos da fibra e os plasmons de superfície.

  • EDVAR DA LUZ OLIVEIRA
  • SMARTCOM: UMA ARQUITETURA INTELIGENTE DE GERENCIAMENTO DE CONSUMO DE ENERGIA PARA SMART HOME

  • Data: 25/08/2017
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  • Com os avanços na tecnologia da informação para a saúde e o bem-estar, as soluções de Smart Home aliadas a tecnologias de Internet das Coisas (IoT), tem aumentado a importância e se tornaram aceitos como meio alternativo de economizar energia quando são baseados em Sistemas de Gerenciamento de Energia Doméstica (sigla em inglês, HEMS). Esta tese define uma arquitetura moderna denominada SmartCoM, que é implementada para monitorar e gerenciar habitações residenciais usando tecnologias IoT. Isso envolve a definição dos parâmetros que podem possibilitar a interoperabilidade entre medição e gerenciamento e as camadas de comunicação de dados, que são os recursos necessários para o monitoramento e medição. A arquitetura SmartCoM é definida em detalhes do ponto de vista do consumidor e as estratégias de otimização são empregadas tanto para o cliente final quanto para a concessionária. As principais vantagens do uso do SmartCoM foram confirmadas pelos resultados numéricos obtidos a partir da arquitetura proposta e sua validação por meio de protótipos oriundos das especificações da arquitetura. Esta tese termina mostrando a posição atual do SmartCoM, além de sugerir novos estágios para essa linha de pesquisa.

  • WILLIE DUARTE TEIXEIRA
  • UTILIZAÇÃO DE TÉCNICAS DE REALIDADE VIRTUAL PARA TREINAMENTO DE OPERAÇÃO DE TERMO-VÁCUO NA MANUTENÇÃO DE ÓLEO TRANSFORMADORES DE POTÊNCIA

  • Data: 23/08/2017
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  • É consenso entre as empresas que atuam no Sistema Interligado Nacional (SIN), que existe uma imprescindibilidade de capacitação de seus profissionais, a fim de que sejam evitadas perdas financeiras e principalmente danos físicos aos envolvidos nas atividades operacionais. No contexto operacional do Sistema Integrado Nacional um dos processos mais importantes na manutenção preventiva e corretiva em equipamentos de subestações é o tratamento do óleo mineral isolante. O óleo mineral isolante tem o papel de elevar a isolação das partes ativas de equipamentos de alta-tensão, sendo assim, a manutenção das condições Físico-Químicas dentro dos padrões, torna-se essencial para o bom funcionamento de equipamentos que operem em alta-tensão. O presente trabalho utiliza técnicas de Realidade Virtual na criação de um ambiente virtual de treinamento na operação de termo-vácuo, que são máquinas responsáveis pelo tratamento do óleo mineral isolante. A proposta desse trabalho foi trazer ganhos qualitativos e quantitativos ao processo de treinamento de profissionais que operam ou operarão tais equipamentos, com enfoque principal aos que estão em processo de formação em instituições formais de ensino, mais especificamente para a utilização em disciplinas de máquinas elétricas e afins.

  • MURILLO AUGUSTO DE MELO CORDEIRO
  • Despite its many benefits, the Distributed Generation (DG) can adversely affect some aspects related to the operation performance of electrical power systems, especially a no so deeply explored point: the interaction between the protection systems and inverter-based connected power generation units. In this dissertation, the impact of inverter-based DGs units on the fuse-recloser coordination schemes used in distribution networks is thoroughly studied. The simulations were conducted using the software package DigSilent Power Factory through several single-phase and three-phase short circuits along the distribution network, considering different fault locations, penetration levels of DGs, operating conditions, and other aspects that impact over the protection miscoordination in an IEEE real test distribution system of 34 busbars. The contribution to the short-circuit current of inverter-based generators is also investigated through simulations on electromagnetic transients models available in the software. The simulation results shows that significant inverter-based DG penetration levels on distribution feeders increase the short-circuit current that passes through the fuse and make it operate faster than the recloser in a fault condition, leading to loss of fuse-recloser coordination in a time frame base. A general discussion of the results is performed, identifying some recommended corrective actions that should be considered in order to maintain the coordination and selectivity between the distribution system protection devices located throughout the network

  • Data: 11/08/2017
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  • Inverter-Based Generator, Photovoltaic Generator, Distribution Systems Protection, Fuse-Recloser Coordination.

  • MARINALDO DE JESUS DOS SANTOS RODRIGUES
  • AVALIAÇÃO TEÓRICA E EXPERIMENTAL DE GERADORES FOTOVOLTAICOS SOB DIFERENTES CONDIÇÕES DE SOMBREAMENTO

  • Data: 10/08/2017
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  • Seja em grandes usinas ou em sistemas fotovoltáicos de pequeno porte integrado a edificações, o sombreamento de módulos fotovoltáicos causa perdas na produção anual de energia, assim como podem danificá-los permanentemente. Dessa forma uma análise experimental a sol se justifica, pois contribui com dados reais, para o entendimento do efeito do sombreamento no desempenho do gerador fotovoltáico. Também poderá proporcionar maior facilidade para estabelecer as melhores áreas em edificações, já construídos ou em projetos, para instalações fotovoltáicas bem como a melhor tecnologia no desempenho de determinado sombreamento. O objetivo deste trabalho é avaliar de forma experimental a influência dos diferentes tipos de sombreamento no desempenho dos módulos fotovoltáicos. Nesse sentido, são abordados aspectos como a determinação do fator de sombreamento sob diferentes condições de operação e a avaliação da produção de energia de módulos e geradores fotovoltáicos tomando como referência parâmetros como eficiência, desempenho global e produtividade.

  • VITOR DA SILVA KATAOKA
  • AVALIAÇÃO DE ALGORITMOS EVOLUCIONÁRIOS MULTIOBJETIVO PARA O PROBLEMA DE ALOCAÇÃO DE BANCOS DE CAPACITORES NA PRESENÇA DE HARMÔNICOS

  • Data: 10/08/2017
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  • The rapid growth of urban areas bring, as a consequence, an increase in the amount of loads connected to the distribution grids. Furthermore, the increase in the demand implies in equal raise in reactive loads, which are known to cause losses in the network. Thus, the utilities have a great challenge ahead, as the dynamics of the load require a greater effort in terms of expansion and improvements of the grid. In an attempt to mitigate the problems caused, the allocation of capacitor banks can become a practical, economical and technically robust solution. Nevertheless, it is extremely important to analyze the sizing and positioning of the banks, in order to achieve the best possible outcome. In parallel, the increasing use of nonlinear loads cause harmonics to appear in the system. When in conjunction with capacitor banks, it is possible to develop the far more dangerous phenomenon of resonance, where the amplitude of some of the harmonics goes beyond acceptable limits, resulting in undesirable effects. In this context, this work proposes a comparison between two multiobjective optimization tehcniques, NSGA-II and SPEA2, to solve the problem of sizing and placement of capacitor banks in electric energy distribution grids, considering the effects of harmonics produced by nonlinear loads.

  • SERGIO HENRIQUE MONTE SANTO ANDRADE
  • ESTRATÉGIAS DE PLANEJAMENTO PARA OTIMIZAÇÃO DO CONSUMO RESIDENCIAL DE ENERGIA ELÉTRICA: UMA ABORDAGEM BASEADA EM SMART HOME E SISTEMAS FUZZY

  • Data: 04/08/2017
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  • O consumo energético residencial vem crescendo de forma contínua ao longo das últimas décadas, entretando, em contrapartida, o fornecimento de energia elétrica não acompanha a mesma taxa de crescimento, tornando-se uma dificuldade a ser tratada pelas empresas do setor elétrico, aos consumidores e ao próprio meio ambiente. Os sistemas de distribuição existentes não são suficientes e possuem limitações no fornecimento de informação adequada, em tempo real, sobre o consumo e outras variáveis elétricas. Também não estão preparados para lidar com os custos da energia variáveis, num contexto de um mercado que tende a estabelecer preços dinâmicos, que dependem de um conjunto de fatores endógenos e exógenos ao setor elétrico.

    Espera-se que a rede elétrica do futuro, atualmente denominada de rede inteligente (Smart Grid), não seja concebida apenas com medições baseadas nas residências, mas também ao nível de consumo de todos os componentes que integram a rede de distribuição das concessionárias. Da parte residencial, os consumidores carecem, de forma geral, de informações relativas ao impacto específico do consumo energético de cada equipamento e, por conseguinte, aos comportamentos necessários para reduzir o seu consumo. Com a falta de um gerenciamento energético adequado nos equipamentos elétricos, por diferentes motivos, o conforto do usuário pode ser impactado, inesperadamente, em um momento de redução energética.

    Nesse contexto, este trabalho tem como objetivo a proposição, implementação e teste de um sistema de monitoramento inteligente, via smartphone, para controle de energia, utilizando-se formas inteligentes de tomada de decisão, com o intuito de fornecer ao usuário formas de manter seu consumo energético, a partir de perfis de consumo, dentro dos padrões de consumo pré-definidos e desejados pelo usuário.

    Como consequências positivas, ter-se-á a redução da demanda energética, por meio dos perfis de consumo que levam em consideração o grau de dependência do indivíduo em relação aos equipamentos elétricos presente na residência, apresentando um menor impacto no bem-estar e no dia a dia do usário final do sistema.

  • NADIME MUSTAFA MORAES
  • MATHEMATICAL MODEL FOR MULTI-OBJECTIVE OPTIMIZATION OF THE ECONOMIC ENVIRONMENTAL DISPUTE OF THERMAL PLANTS USING NSGA-II
  • Data: 14/07/2017
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  • One of the priority tasks for thermoelectric plants is to supply the requested energy demand, ensuring the lowest possible cost. This task is more important in the Northern Region of Brazil, especially in the Industrial Hub of Manaus (PIM) and in the city itself, where a large part of this energy is supplied by Thermoelectric Power Plants (UTE). The selection of generators and their work regime is known as the Economic Dispatch (DE). The essential objective of ED is to operate UTEs by meeting demand at the lowest possible cost of fuel. However, the worldwide concern about pollution caused by fossil fuels in recent times to minimize fuel costs can not be considered the only objective to be achieved in the UTEs and limiting the emission of pollutants has become another primary objective. Thus, the Environmental Economic Dispatch (DEA) appears, which seeks not to reduce costs, but also emissions. To solve the optimization of this task there are several deterministic as well as heuristic methods. One of the most used methods according to the literature is the Genetic Algorithm of Non-dominated Classification, NSGA-II, considering two objective functions, a function of fuel cost and another quantity function. In this thesis, the proposed solution has the following contributions: it develops a new and unprecedented function to evaluate the environmental contamination produced by the UTEs that, in addition to minimizing the amount of pollutants, takes into account the influence of pollutants more harmful to the environment. This function, called the Emissions Index, is applied to the engines of two UTEs in the city of Manaus with satisfactory results. The Emissions Index and the traditional fuel cost function is optimized using the NSGA-II, determining optimal solutions for output power in several characteristic and non-characteristic scenarios of the plants, and can be applied to any thermoelectric plant. In order to analyze the viability of the solution proposed by this thesis, a set of ten thermal generating units of a UTE of the city of Manaus and the IEEE 118-bar System were used as case studies, demonstrating the robustness of the proposal in what refer to the solution presented. These results were significant considering the Emissions Index and using the optimization procedure of the non-dominated classification algorithm II (NSGA-II). This new DEA methodology enables specialists in the area to reduce costs and generate generation planning.

  • YASMIN CHRISTINE CORREA MATOS
  • DETECÇÃO DE FRAUDES EM UNIDADES CONSUMIDORAS DE ENERGIA ELÉTRICA USANDO ÁRVORES DE DECISÃO

  • Data: 11/07/2017
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  • DETECÇÃO DE FRAUDES EM UNIDADES CONSUMIDORAS DE ENERGIA ELÉTRICA USANDO ÁRVORES DE DECISÃO

  • MAILSON BORGES TELES
  • AVALIAÇÃO OPERACIONAL DAS DIFERENTES ARQUITETURAS DE INTERLIGAÇÃO DE GERADORES FOTOVOLTÁICOS À REDE ELÉTRICA DE BAIXA TENSÃO

  • Data: 13/06/2017
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  • Este trabalho visa avaliar experimentalmente as tecnologias string, microinversor e conversor c.c.-c.c., de modo a contribuir para a construção do conhecimento científico da aplicação das diferentes arquiteturas de interligação de geradores fotovoltáicos a rede elétrica convencional. Para isso são utilizados diferentes sistemas instalados no laboratório do GEDAE/UFPA, região norte do país. Procurou-se comparar os desempenhos de acordo com as informações nos diferentes mecanismos de aquisição de dados disponíveis no laboratório. Tendo em vista que alguns desses mecanismos de aquisição de dados fornecem somente o valor da energia acumulada ao longo do dia, foi dado um enfoque na operação global dos diferentes sistemas analisados. Contudo, naqueles sistemas onde maiores detalhes da operação foram monitorados, seja por sistemas de aquisição do próprio equipamento ou por equipamentos existentes no próprio laboratório (osciloscópio Fluk, Watimetro, etc), análises pontuais importantes, com mais detalhes da operação do sistema, foram desenvolvidas. Os resultados obtidos mostram que o conversor c.c.-c.c. apresentou desepenhos superiores aos demais sistemas monitorados. Contudo constatou-se a ocorrência de problemas devido ao processo de pareamento dos concersores c.c.-c.c. na operação dos sistemas que permanecem até os dias de hoje.

  • FABIO BARROS DE SOUSA
  • REGENERADOR 3R TOTALMENTE ÓPTICO BASEADO EM INTERFERÔMETRO DE MACH-ZEHNDER DE FIBRA DE CRISTAL FOTÔNICO ALTAMENTE NÃO LINEAR

  • Data: 26/05/2017
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  • A regeneração totalmente óptica está em constante investigação, ela consiste em tratar os sinais ópticos degradados durante a transmissão do sinal por um link fibra óptica monomodo padrão ITU G.652, amplificadores e transmití-los sem distorções, crosstalk e ruídos até o receptor. Para sinais com altas taxas de bits a única opção é a regeneração totalmente óptica. Assim, os regeneradores totalmente ópticos oferecem inúmera vantagens em compração aos regeneradores elétricos, dentre elas destacam-se a redução de componentes e custos, além de evitar o gargalo eletrônico. Por essas e outras vantagens que a regeneração elétrica vem sendo substituída pela regeneração totalmente óptica. Neste trabalho é proposto um regenerador 3R totalmente óptico baseado em interferômetro de Mach-Zehnder, cujo um dos braços é composto por uma fibra de cristal fotônico totalmente não linear. Através deste projeto fio possível obter uma regeneração completa (Reamplificação, Reformatação e Ressincronização) do sinal, com valores ótimos de OSNR, de fator de qualidade (fator Q) e baixa taxa de erro de it (BER).

  • BRUNO WALLACY MARTINS LIMA
  • MODELO PARA REPRESENTAÇÃO DE AMBIENTES 3D UTILIZANDO COMPOSIÇÃO DE MODOS DO MÉTODO FDTD-2D

  • Data: 26/05/2017
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  • As informações das características da propagação do sinal eletromagnético é essencial nos projetos de sistema de comunicação, sobre tudo, aos aplicados ao ambiente interior. Com os modelos de predição é possível a caracterização do canal, a determinação da posição ótima de uma antena transmissora, para maximizar a área de cobertura, e identificar fenômenos de multipercurso, calculados através do perfil de retardo de potência. Neste trabalho foi empregado o método determinístico das diferenças finitas no domínio do tempo (FDTD), em duas e em três dimensões. Através do método FDTD 3D foi desenvolvido uma representação da antena discônica capaz de reproduzir de forma equivalente o sinal da antena utilizado em uma campanha de medições. A vantagem da representação da antena em FDTD 3D está no fato da modelagem do ambiente sem a necessidade de maior discretização computacional. Além disso, foi desenvolvido uma metodologia para correção do método FDTD 2D para fornecer resultados equivalentes aos obtidos com a versão 3D do método. A correção ao método FDTD 2D possibilita a análise da propagação do sinal eletromagnético através de computadores de baixo custo, em termos de memória e tempo de processamento.

  • MARCELA ALVES DE SOUZA
  • SISTEMAS FOTOVOLTAICOS APLICADOS EM REDES MÓVEIS HETEROGÊNEAS

  • Data: 22/05/2017
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  • As operadoras de telecomunicações móveis enfrentam desafios contínuos de ampliação de capacidade e cobertura da rede, de forma a atender à demanda crescente por melhor qualidade de serviço e experiência dos usuários em aplicações móveis de alta velocidade. Estas frequentes melhorias têm sido seguidas pelo aumento sem precedentes do consumo de energia elétrica, que ocorre devido a densificação de redes móveis heterogêneas (HetNet – Heterogenous Network) através de small cells e consequente acréscimo do número de dispositivos no backhaul móvel, os quais são necessários para conectar todas as estações base por meio da camada de acesso ao núcleo da rede. Ainda que seja considerada uma estratégia eficientemente energética, as small cells aumentam consideravelmente o consumo energético da HetNet, devido a expansão do backhaul, ameaçando seus benefícios e trazendo despesas relacionadas ao custeio com energia elétrica para as operadoras de rede móvel. Para esse problema, propõe-se a exploração de fontes de energia renováveis, em especial a fotovoltaica, que visa diversificar a matriz energética e mitigar o volume de emissões de CO2, além de possuir viabilidade técnica e econômica quando comparada a fontes convencionais de geração de energia. Assim, esta pesquisa tem o objetivo de fazer uma avaliação técnico-econômica para a aquisição, implantação e operação de sistemas fotovoltaicos no contexto de redes móveis heterogêneas, considerando conjuntamente o consumo energético das redes de rádio, fronthaul e backhaul. A partir dos resultados evidencia-se viabilidade financeira quanto a adoção de estruturas fotovoltaicas, bem como sustentabilidade ambiental através da redução considerável das emissões de CO2 na atmosfera. 

  • EDERSON COSTA DOS SANTOS
  • ESTRATÉGIAS DE PLANEJAMENTO DE SMART GRIDS: UMA ABORDAGEM BASEADA EM META-HEURÍSTICAS E SIMULAÇÃO

  • Data: 15/05/2017
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  • Nos próximos anos, o sistema elétrico de potência tende a passar por grandes modificações, as quais concentram-se em diversos níveis e sub-áreas tais como nos sistemas de geração, transmissão e distribuição, todos voltados ao conceito de smart grids. este conceito caracteriza-se pela inclusão das novas tecnologias digitais no sistema elétrico, com o intuito trazer segurança, velocidade, monitoramento, dentre outros muitos benefícios. no entanto, para pleno desenvolvimento desta rede, muito ainda necessita ser feito em diversas áreas de pesquisa. nesta linha, este trabalho apresenta um modelo completo de caracterização de smart grid a partir de protocolos já existentes, formalizando assim, um modelo de planejamento. também foi incluído no estudo, a análise de um método de otimização, ao qual utiliza algoritmos inteligentes para potencialização da rede. a solução proposta baseia-se na alocação otimizada de equipamentos em uma rede de comunicação de dados plc (power line communication), sobre aplicações smart grid. para isso foi desenvolvido um algoritmo que realiza a identificação dos equipamentos e calcula a quantidade deste que é necessário sem que haja perda dos padrões de qualidade. assim, com o modelo proposto, foram realizadas simulações no software de eventos discretos network simulator – 3. os resultados mostram uma diminuição significativa no quantitativo de repetidores, mantendo níveis mínimos de qos para as aplicações. 

  • ANDRE MELO DE MORAIS
  • ANÁLISE DA AÇÃO DE EFICIÊNCIA ENERGÉTICA ATRAVÉS DO GUIA DE M&V DA ANEEL E DO RETSCREEN CONSIDERANDO A IMPLEMENTAÇÃO DE ILUMINAÇÃO A LED NO COMPLEXO PREDIAL DA SUDAM

  • Data: 28/04/2017
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  • A matriz energética mundial é bastante dependente das fontes não renováveis de energia, assim, a adoção de novas tecnologias e estratégias que visem à eficiência energética são ações emergentes mundialmente, face às mudanças climáticas, escassez dos recursos naturais e demanda crescente de energia. Nesse sentido, o progresso autônomo da tecnologia dos LEDs, do inglês “Light Emitting Diode”, e o progresso induzido, praticado pelo governo brasileiro, em eficiência energética são alavancas propulsoras para o crescimento das medidas de conservação de energia em todos os setores da economia. É com esse intento que este trabalho vem propor o emprego do LED na iluminação dos ambientes da Superintendência do Desenvolvimento da Amazônia (SUDAM), uma Autarquia da Administração Pública Federal, para reduzir o consumo de energia na Superintendência do Desenvolvimento da Amazônia, além de servir como parâmetro para os demais Órgãos do Setor Público. Para subsidiar a proposta é utilizada a metodologia do Guia de M&V (Medição e Verificação) da ANEEL e o software RETScreen® tendo como premissas o diagnóstico energético e os resultados obtidos com a substituição de algumas lâmpadas fluorescentes antigas por lâmpadas LED, ambos realizados na SUDAM. A análise concluiu que a ação de eficiência energética proposta, além de possuir viabilidade de aplicação com recursos próprios da Instituição, também pode se configurar como uma proposta de projeto válida para chamadas públicas, que devem ser ofertadas pela CELPA, no âmbito do Programa de Eficiência Energética regulado pela ANEEL.  

  • ADAM DREYTON FERREIRA DOS SANTOS
  • OUTPUT-ONLY METHODS FOR DAMAGE IDENTIFICATION IN STRUCTURAL HEALTH MONITORING

  • Data: 27/04/2017
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  • In the structural health monitoring (SHM) field, damage identification based on the vibration response measurements from engineering structures has become a crucial research area due to its potential to be applied in real-world problems. Assuming that the vibration signals are often available and can be measured by employing different types of monitoring systems, when one applies appropriate data treatment, damage-sensitive features can be then extracted and used to assess early and progressive structural damage. However, real-world structures are subjected to regular changes in operational and environmental conditions (e.g. temperature, relative humidity, traffic loading and so on) which impose difficulties to identify structural damage as these changes influence different damage-sensitive features in a distinguish manner. Currently, the separation of changes in damage-sensitive features caused by damage from those caused by changing operational and environmental conditions remains as one of the major challenges to transit SHM technology from research to practice. In this thesis, to overcome this drawback, the SHM process is posed in the context of the statistical pattern recognition paradigm, where machine learning is the science of getting computers and algorithms to model the reality without knowing the physical laws of structures. This paradigm intends to pave the way for data-based models applicable to detect damage in structural systems of arbitrary complexity. The objective of this thesis is to adapt, develop, and apply several output-only methods based on machine learning and artificial intelligence for feature extraction and statistical modeling for feature classification capable of detect damage on structures under unmeasured operational and environmental influences. To test the performance of adapted and novel methods, as well as to compare they to state-of-the-art methods, the approaches are first applied on standard data sets measured from a laboratory three-story frame structure and then on response data from real-world structures – Z-24 and Tamar Bridges. The results demonstrated that the novel methods have better classification performance than the alternative ones in terms of false-positive and false-negative indications of damage, suggesting their applicability for real-world SHM solutions. If the proposed methods are compared to each other, the cluster-based ones, namely the global expectation-maximization approaches based on memetic algorithms, prove to be the best techniques to learn the normal structural condition without loss of information or sensitivity to the initial parameters and to detect damage (total errors equal to 4.4%)

  • REINALDO CORRÊA LEITE
  • ANÁLISE MULTIFÍSICA  E EXPERIMENTOS EM SENSORES ÓPTICOS USADOS NA MEDIÇÃO DE TEMPERATURA EM ROTORES DE HIDROGERADORES

  • Data: 12/04/2017
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  • O rotor é um dos principais componentes de um hidrogerador e está exposto a estresses mecânicos e térmicos durante sua operação normal. Quando esses estresses excedem os limites de tolerância, o rotor sofrerá desgastes de forma prematura. Estresses térmicos afetarão geralmente as isolações entre espiras (voltas da bobina de cobre que forma o enrolamento) e para a terra dos polos do rotor. Este fato pode levar a necessidade de se fazer uma recuperação dos polos mais cedo do que necessário ou, em alguns casos, a faltas para a terra, que poderão causar danos extensos.

    A medição de temperatura do rotor não é algo trivial devido ao fato de esta peça estar em movimento e sob alta tensão elétrica. O fato de o enrolamento do rotor estar sob tensão elétrica impede o uso de sensores de temperatura metálicos, seu uso poderia causar curtos-circuitos entre as espiras do enrolamento. Outra dificuldade é a retirada da informação (temperatura) do rotor por este estar em movimento, o uso de cabos é proibitivo.

    As Redes de Bragg ou Fiber Bragg Gratings (FBG) oferecem novas possibilidades de monitorar de forma precisa a temperatura no enrolamento do rotor. Dezenas de sensores podem ser montados em série em uma única fibra para medir a temperatura em diversos pontos do enrolamento do rotor. Neste trabalho estudamos o efeito das grandezas termomecânicas nos sensores FBG através de testes em laboratório em maquetes estáticas e dinâmicas e simulação numérica multifísica usando o Método dos Elementos Finitos (MEF) em um modelo do instalação do sensor FBG na maquete estática e um rotor real. Tais sensores instalados diretamente na superfície do enrolamento do rotor são isolados do ar por uma camada de silicone. Por causa do gradiente de temperatura nesta estrutura, o sensor fica exposto a estresses termomecânicos que podem levar a sua deformação. Como os sensores FBG são sensíveis tanto à temperatura como à deformação, o conhecimento de cada efeito de forma separada é necessário para garantir que as leituras de temperatura não sejam afetadas pela deformação. Resultados experimentais obtidos em uma maquete do enrolamento do rotor na qual compararam-se as leituras de temperaturas dos sensores FBG e termistores, mostraram uma diferença de temperatura de 4,5°C entre os sensores FBG em relação àquela definida pelos termistores que foram usados como referência.

  • ANDERSON DE FRANCA SILVA
  • CONTROLADOR GMV APLICADO À REGULAÇÃO DO ÂNGULO DE PASSO EM UM SISTEMA DE CONVERSÃO DE ENERGIA EÓLICA: UMA ABORDAGEM LINEAR, PREDITIVA E ESTOCÁSTICA

  • Data: 07/04/2017
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  • Nesta pesquisa, foram investigadas técnicas de controle linear, preditivo e estocástico, aplicadas ao problema de regulação do ângulo de passo de uma Turbina Eólica. A topologia do Sistema de Conversão de Energia Eólica (SCEE) estudado é do tipo Velocidade Fixa, com ângulo de passo variável. Os SCEE, de maneira geral, são sistemas que, durante seu funcionamento, estão sujeitos à constante entrada de perturbações do tipo estocásticas. Este tipo de perturbação, em muitos casos, é negligenciado, o que irá afetar de maneira negativa o desempenho de controladores cujo o projeto foi baseado em modelos determinísticos. Pesquisas desenvolvidas dentro da Teoria de Controle Preditivo e Estocástico, têm comprovado os benefícios de se realizar o projeto de controladores baseados em modelos que consideram as parcelas, determinística e estocástica, do processo. Seguindo esta mesma abordagem de projeto, foi desenvolvido, nesta dissertação, o projeto de Reguladores do Ângulo de Passo (RAP), por meio da técnica de Augmentação Estocástica (AE) de controladores determinísticos. Os principais objetivos buscados foram: minimizar o consumo de energia do sistema de controle; e reduzir os custos relacionados à manutenção e troca dos atuadores no sistema de regulação do ângulo de passo. Foram realizados testes em um simulador de SCEE da MathWorks®. Os resultados dos testes comprovam o bom desempenho dos RAP projetados através da AE, os quais alcançaram os objetivos buscados no desenvolvimento desta pesquisa.

  • RAFAEL CAVALCANTE DE OLIVEIRA
  • METODOLOGIA PARA O CÁLCULO DE PERDAS TÉCNICAS E NÃO TÉCNICAS DE ALIMENTADORES DE DISTRIBUIÇÃO VIA ESTUDOS DE FLUXO DE CARGA PELO MÉTODO SOMATÓRIO DE POTÊNCIAS MODIFICADO

  • Data: 04/04/2017
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  • Fundamental para a atividade econômica, o setor de energia elétrica no Brasil é organizado pela agência reguladora pertinente, a ANEEL. Esta regula e fiscaliza a produção, transmissão/distribuição e comercialização de energia elétrica em conformidade com as políticas e diretrizes do governo federal. Entre outras funções, a ANEEL define os valores de tarifas a serem cobradas pelas concessionária através de ferramentas como as Revisões Tarifárias. As perdas não técnicas (ou perdas comerciais) da distribuidora são parte da composição da tarifa de energia, sendo repassadas ao consumidor final, dentro de um limite pré-estabelecido. Portanto diminuir as perdas comerciais é tema de fundamental importância para as distribuidoras de energia, pois aumenta a rentabilidade da empresa e diminui os custos da energia ao usuário final. Este trabalho, sendo fruto de projeto de pesquisa realizado em parceria entre a distribuidora de energia do estado do Pará, CELPA, e a Universidade Federal do Pará, visa desenvolver uma nova metodologia no âmbito do planejamento operacional, incluindo informações de perdas técnicas e não técnicas nos estudos de fluxo de carga utilizando método Somatório de Potência modificado.

    Para tanto, inicialmente é feita uma análise do cenário do setor elétrico brasileiro, com ênfase nas fraudes e furtos de energia, e os impactos desta realidade do ponto de vista financeiro tanto para as concessionárias de energia quanto para os clientes, e também os impactos na prestação de serviços a estes consumidores. A seguir apresenta-se uma nova metodologia, capaz de determinar de forma mais assertiva o estado real de operação da rede de distribuição, por levar em conta as perdas comerciais de energia, juntamente com medições reais de potência ativa e reativa injetada nos alimentadores, no ponto de acoplamento com a subestação. Aplica-se o método elaborado utilizando tanto um alimentador de teste do IEEE 13-barras, quanto um alimentador urbano da rede metropolitana de Belém, pertencente à concessionária de energia do Pará, CELPA, e os resultados obtidos são então apresentados e analisados.

  • ANGELA COSTA SANTA BRIGIDA
  • CARACTERIZAÇÃO E DESENVOLVIMENTO DE SENSORES ÓPTICOS DE CORRENTE ELÉTRICA PARA APLICAÇÕES EM LINHAS DE ALTA TENSÃO

  • Data: 03/04/2017
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  • No trabalho desta Tese foram implementados e caracterizados sensores de corrente magneto-óptica, para aplicações de medição e proteção em sistemas de alta potência. Nomeadamente, sensor bulk e sensor com fibra de cristal fotônico (PCF). Ambos, são baseados no efeito Faraday, utilizando uma configuração polarimétrica em dupla quadratura, associando, assim, o campo magnético a medição de corrente elétrica. Este trabalho foi, então, dividido, em dois momentos. No primeiro, foi estudado o sensor Bulk. Neste caso, o protótipo do sensor bulk utilizou-se um prisma de vidro Schoott SF57 de 8cm de comprimento com alta constante de Verdet e baixa birrefringência. Ele foi incorporado em um invólucro de Nylon adequado para aplicações de fixação na linha de alimentação. A operação do sensor é caracterizada e comparada usando diodos Super Luminescentes distintos como fontes ópticas, com emissão a 650 nm, 830 nm e 1550 nm. A operação ótima a 830nm é relatada com uma resposta linear até 65,28kA, com classe de precisão de 0,1 ou 0,2 considerando uma corrente nominal de 1,2 e 0,3 kA (raiz quadrada média), respectivamente. Doze procedimentos de calibração realizados ao longo de seis dias mostraram um erro máximo estimado de 11m A. Foram feitas medições preliminares de 40 a 400 Hz. O sensor foi exposto a sinais transientes inferiores a 10 μs que demonstraram seu uso em aplicações de proteção. No segundo momento, estudou-se a possiblidade de usar fibras PFC no sensoriamento de corrente eletrica. Basicamente, foi avaliado desempenho desse novo sensor de corrente, usando uma configuração polarimétrica, como já mencionado, sendo testado e comparado com a fibra monomodo a 633 nm. Em particular, estas fibras foram testadas enrolando-as em torno de um condutor eléctrico utilizando três diâmetros de enrolamento distintos com voltas diferentes. Parâmetros, tais como a sensibilidade e a linearidade do sensor foram investigadas. Os resultados mostraram uma relação linear muito boa com a corrente e a sensibilidade dependente do diâmetro do enrolamento e do número de espiras. Isto é, para um diâmetro do enrolamento maior, a fibra com menor periodo circular apresentou maior sensibilidade e para o menor diâmetro de enrolamento o melhor resultado de sensibilidade foi para a fibra com maior periodo circular. Também, os resultado apresentados mostram que fibra errolada (40 rotações por metro) é capaz de suprimir de forma bastante eficaz os efeitos da birrefringência induzida pela dobra em comparação com uma fibra tradicional.

  • RAPHAEL PABLO DE SOUZA BARRADAS
  • SIMULAÇÃO DE ENSAIO DE IMPULSO ATMOSFÉRICO EM TRANSFORMADORES DE BAIXA INDUTÂNCIA UTILIZANDO CIRCUITO GLANINGER E PROGRAMA ATP PARA O LABORATÓRIO DE EXTRA ALTA TENSÃO DA UFPA

  • Data: 31/03/2017
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  • Uma das maiores dificuldades observadas em laboratórios de alta tensão é o ajuste da forma de onda do impulso de tensão a ser utilizado nos ensaios. Esta dificuldade deve-se ao fato de que, na maioria das vezes, não se conhece a capacitância do objeto sob ensaio, não sendo possível realizar um cálculo exato dos parâmetros a serem utilizados no gerador de impulsos. Nos casos de ensaios em transformadores, estas dificuldades aumentam visto que, além da capacitância inerente da sua isolação, há também uma contribuição de indutância ao circuito de ensaio, proveniente de seus enrolamentos. Isto dificulta ainda mais a obtenção de uma forma de onda normalizada, de acordo com a norma NBR IEC 60060-1. A presente Dissertação de Mestrado apresenta e avalia metodologias que permitam a realização de ensaios normatizados de impulso de tensão em transformadores com baixas indutâncias, comuns nos sistemas de energia elétrica. Serão destacados os resultados obtidos com a inserção de um circuito Glaninger, comparado com a metodologia baseada no aumento da resistência paralela total do circuito em teste. As simulações computacionais são realizadas com o auxílio do programa ATP (Alternative Trasient Program), utilizando parâmetros reais dos equipamentos de alta tensão do Laboratório de Extra Alta tensão da Universidade Federal do Pará (LEAT). Através da introdução de um circuito Glaninger devidamente adaptado, apresenta-se a solução para o problema de deformação da forma de onda padronizada de impulso que acontece em ensaios de transformadores, com critérios estabelecidos pelas normas vigentes.

  • VANDERSON CARVALHO DE SOUZA
  • CONTROLE LOCAL DE POTÊNCIA REATIVA EM GERADORES FOTOVOLTAICOS PARA A MELHORIA DA REGULAÇÃO DE TENSÃO EM REDES DE DISTRIBUIÇÃO

  • Data: 31/03/2017
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  • Esta dissertação apresenta um estudo de simulação dinâmica com a finalidade de mostrar os impactos da geração fotovoltaica na operação do regulador de tensão (RT). Essa investigação é realizada por meio do software Análise de Transitórios Eletromecânicos (ANATEM), desenvolvido pelo Centro de Pesquisas de Energia Elétrica (Cepel). Os modelos dinâmicos do RT e do gerador fotovoltaico (GFV) foram desenvolvidos no ANATEM via Controle Definido pelo Usuário (CDU). As curvas de potência do GFV (dado de entrada do modelo), ao longo do dia, foram obtidas por meio de uma campanha de medição realizada numa residência na cidade de Belém/PA com taxa de amostragem de 15 segundos. Três cenários de irradiação solar são considerados nas simulações: dia claro (sem variabilidade), dia com variabilidade moderada e dia com alta variabilidade. O alimentador teste é o IEEE 33 barras.

    A dinâmica da carga demandada durante o dia foi representada por meio de uma curva de carga e dessa forma as sobretensões ocasionadas pela baixa demanda de potência e elevada injeção de potência ativa na rede elétrica (que geralmente ocorre por volta das 12 horas) puderam ser analisadas. Duas estratégias de controle, via controle local de potência reativa, foram testadas. A estratégia 01, embora muito eficiente em relação ao número de mudanças de tap do regulador de tensão, não é indicada para tratar problemas de sobretensão. A estratégia 02 é efetiva tanto para os problemas de sobretensão quando para os efeitos da variabilidade na operação do regulador de tensão.

  • ANDREY JOSE TORRES DA SILVA
  • NOVA ESTRATÉGIA DE REPOSIÇÃO DE CACHE PARA REDES NDN

  • Data: 31/03/2017
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  • Com a crescente demanda por conteúdo multimídia incentivada pela evolução dos smartphones, estima-se que em poucos anos, aproximadamente 75% do tráfego nas redes móveis seja oriundo de aplicações de vídeo. Tal fato deve ser levado em conta para que as funcionalidades atualmente existentes no transporte de informações nas redes, sejam melhor adaptadas ao transporte de conteúdo multimídia, visando a melhoria na qualidade do serviço proporcionando ao cliente, assim como a minimização do custos para as operadoras.

    Uma maneira de otimizar a relação custo-benefício nas redes atuais é fazer uso de servidores de cache, armazenando em diferentes locais da rede conteúdos frequentemente requisitados por diferentes usuários, como por exemplo vídeos populares da Internet. Tal funcionalidade exige certo investimento como Named Data Networking (NDN) implementa cache de maneira praticamente nativa.

    Dada a importância da utilização de cache em redes NDN, estudos para otimizar a maneira como este é realizado são essenciais, principalmente no que se refere a definir qual conteúdo deve ser mantido em cache. Assim, este trabalho propõe um novo algoritmo proposto obtém um melhor uso do cache em comparação a outros algoritmos bastante utilizados na literatura.

  • HEITOR ALVES BARATA
  • IMPACTO DE REDES DE DISTRIBUIÇÃO COM MASSIVA CONEXÃO DE GERADORES FOTOVOLTAICOS NA ESTABILIDADE DE TENSÃO DE LONGO-PRAZO EM SISTEMAS DE POTÊNCIA

  • Data: 31/03/2017
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  • Este trabalho visa mostrar o impacto de geradores distribuídos fotovoltaicos, conectados diretamente nas redes de distribuição, na estabilidade de tensão de longo prazo usando simulação completa no domínio do tempo. O efeito de diferentes níveis de penetração da geração fotovoltaica é investigado. Também são investigados diferentes modelos de geração distribuída e de carga: 1) Carga e GD representados por modelo ZIP e injeção de potência, respectivamente, na SE de AT; 2) Carga e GD representados por modelo ZIP e equivalente dinâmico, respectivamente, na SE de AT; 3) Carga e GD representados por modelo ZIP e modelo dinâmico, respectivamente, distribuídos ao longo de uma rede de distribuição de MT. Equipamentos como transformadores com comutação de tap sob carga (OLTC, do inglês, “On-Load Tap Changer”), limitadores de sobrecorrente de excitação (OEL, do inglês, “Overexcitation Limiter”), cargas estáticas e autotransformadores reguladores de tensão são levados em consideração nas análises, pois afetam significativamente a estabilidade de tensão de longo prazo. Um dos métodos de análise utilizado para estudos de estabilidade de tensão baseia-se na curva PV (“Power-Voltage”), a qual indica o carregamento máximo do sistema de potência, contribuindo para a visualização da margem de estabilidade do sistema. Além disso, as curvas PV podem ser obtidas para diferentes cenários de crescimento de carga e geração. As investigações são realizadas por meio do uso de software de análise de rede (ANAREDE) e software de análise de transitórios eletromecânicos (ANATEM), desenvolvidos pelo Centro de Pesquisas de Energia Elétrica (CEPEL). A modelagem estática dos geradores fotovoltaicos é considerada como barras PQ, e a modelagem dinâmica é baseada no modelo PVD1 da WECC (Western Electricity Coordinating Council) implementada via Controle Definido pelo Usuário (CDU) no ANATEM. A proteção mandatória da geração fotovoltaica também é considerada. O sistema de potência estudado é uma junção de um sistema de transmissão de 11 barras com sistemas de distribuição da UKGDS (United Kingdom Generic Distribution System) de 76 barras cada. Os resultados das simulações ilustram o impacto dos sistemas de distribuição UKGDS com massiva conexão de geradores fotovoltaicos na estabilidade de tensão do sistema de transmissão considerando distintas representações e modelos de carga e geração distribuída, diferentes níveis de penetração, além de diferentes perfis de injeção de potência ativa da geração fotovoltaica.

  • RICARDO DA SILVA PEREIRA
  • METODOLOGIA PARA REDUÇÃO DO CONSUMO DE ÓLEO DIESEL EM SISTEMAS DE GERAÇÃO TERMOELÉTRICA USANDO MISTURAS DE ÓLEO VEGETAL COM ADMISSÃO DE GÁS HIDROGÊNIO

  • Data: 30/03/2017
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  • METODOLOGIA PARA REDUÇÃO DO CONSUMO DE ÓLEO DIESEL EM SISTEMAS DE GERAÇÃO TERMOELÉTRICA USANDO MISTURAS DE ÓLEO VEGETAL COM ADMISSÃO DE GÁS HIDROGÊNIO

  • CARLOS JEAN FERREIRA DE QUADROS
  • CONTROLE DE QUALIDADE DE EXPERIÊNCIA PARA DISSEMINAÇÃO DE VÍDEOS EM TEMPO REAL SOBRE REDES AD HOC VEICULARES

  • Data: 24/03/2017
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  • A disseminação de vídeos em tempo real sobre Redes Veiculares (do Inglês, Vehicular Ad hoc Networks - VANETs) é fundamental para inúmeros serviços, como: vídeos de emergência, anúncios, monitoramento inteligente etc. Essas aplicações enfrentam muitos desafios devido os requisitos de qualidade de vídeo, topologia dinâmica e ambiente das VANETs. Para lidar com esses desafios e reduzir a sobrecarga de roteamento na rede, protocolos de roteamento estatísticos (do Inglês, Statistical Routing Protocols - SRPs) tem sido propostos para a distribuição de fluxos de vídeo em VANETs, normalmente usando parâmetros de posicionamento e Qualidade de Serviço. Porém, além desses parâmetros, a disseminação de vídeo, considerando a perspectiva dos usuários, também exige a preocupação com questões relacionadas à aceitação pelo Sistema Visual Humano (SVH). Devido os diferentes requisitos e a estrutura hierárquica de vídeos, apenas parâmetros de posição e do nível de rede não são suficientes para disseminação de vídeo com níveis satisfatórios de Qualidade de Experiência (do Inglês Quality of Experience - QoE) e alcançabilidade. Esta tese foca na melhoria do QoE dos vídeos em tempo real disseminados em VANETs. Assim, propõe-se um mecanismo cross-layer para Broadcast baseado em Receptor dirigido a QoE (BRQ), modularmente acoplado em SRPs para oferecer parâmetros relacionados a vídeo no processo de seleção de nodos encaminhadores dos fluxos de vídeo e manutenção de rotas. A partir do BRQ, os nodos da rede decidem por eles mesmos, se devem retransmitir as sequências de vídeo ou não, melhorando a capacidade do sistema em distribuir vídeos com melhor QoE. No topo dessa arquitetura, uma técnica para Correção de Erros, nomeadamente Entrelaçamento (do Inglês, Interleaving), foi adicionada, permitindo mitigar ainda mais os efeitos de perdas em rajadas de quadros relativos ao ambiente de conexão inseguro de VANETs. Para validação, o mecanismo BRQ foi adicionado a um SRP projetado usando a estratégia de encaminhamento baseada em Distância, chamado de protocolo DBRQ (Distance BRQ). Os resultados mostram que os ganhos do protocolo DBRQ comparado a outros atuais SRPs, forceceram disseminação de vídeo com maior suporte à QoE, menos sobrecarga de roteamento e alcançabilidade satisfatória.

  • JOARY PAULO WANZELER FORTUNA
  • FPGA - BADES TESTBED FOR FRONTHAUL SIGNAL COMPRESSION: IMPLEMENTATION AND VALIDATION

  • Data: 24/03/2017
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  • A demanda por serviços de dados móveis com maior taxas de tranferências e menores custos forçou nos últimos anos a rede de acesso via rádio a ser repensada. Dentre as várias arquiteturas propostas a que mais se destaca é centralização dos recursos da rede como forma de reduzir custos através da reutilização e virtualização das Estações Rádio Base (ERB). Com a centralização do processamento digital das ERB é necessário repensar o enlace entre a geração do sinais e sua conversão para o mundo analógico, chamado Fronthaul. Esse trabalho visa apresentar a implementação e validação de uma plataforma para testes com o enlace Fronthaul sob Ethernet. O trabalho foi desenvolvido em VHDL e testado em placas FPGA utilizando uma rede Ethernet real.

  • IGOR MEIRELES DE ARAUJO
  • ESTRATÉGIAS DE PARALELISMO COM GPGPU PARA OTIMIZAÇÃO DO PROCESSAMENTO DO CÁLCULO DO FLUXO DE CARGA EM SISTEMAS ELÉTRICOS DE POTÊNCIA

  • Data: 23/03/2017
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  • O cálculo do fluxo de carga provê informações básicas de um sistema elétrico de potência, informações necessárias para que sejam realizados outros estudos. O fluxo de carga só pode ser realizado em estado de regime permanente, caso o sitema sofra alguma alteração, seja por variação nas cargas ou modificações dos equipamentos de controle, este cálculo é necessário ser refeito. Por essa necessidade de constantemente ter que realizar o fluxo de carga, começou-se uma busca por otimizar o tempo necessário desta tarefa. A forma mais abordada para isso foi a utilização de computação paralela, onde a partir do século XXI, começou a ser utilizado a Graphic Processing Units (GPU) como uma alternativa de melhor custo benefício para execuções em arquitetura paralelas. Esta prática de utilização de GPU's não só para processamento gráfico ficou conhecida pelo termo General Purpose Graphics Processing Unit (GPGPU). Enquanto diversos trabalhos têm tirado proveito pela utilização de GPGPU nos cálculos do fluxo de carga, contudo, não há um consenso sobre qual estratégia utilizar para paralelizar neste hardware. Ficando a cargo de cada autor o trabalho de desenvolver seu próprio método, o que dificulta a utilização desta arquitetura para a implementação desses cálculos, tanto para fins acadêmicos, quanto para o mercado. Por este motivo, este trabalho visa analisar as etapas do fluxo de carga, identificando quais estão mais aptas a paralelização em GPGPU com o intuito de realizar múltiplos cálculos do fluxo de carga simultâneos.

  • ÁTHILA SANTOS DE LIMA
  • ALOCAÇÃO E DIMENSIONAMENTO MULTIOBJETIVO DE BANCOS DE CAPACITORES EM REDES DE DISTRIBUIÇÃO CONSIDERANDO RESTRIÇÕES DE RESSONÂNCIA HARMÔNICA

  • Data: 13/03/2017
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  • ALOCAÇÃO E DIMENSIONAMENTO MULTIOBJETIVO DE BANCOS DE CAPACITORES EM REDES DE DISTRIBUIÇÃO CONSIDERANDO RESTRIÇÕES DE RESSONÂNCIA HARMÔNICA

  • EDEMIR MARCUS CARVALHO DE MATOS
  • QUALIDADE DE VÍDEO BASEADA EM PERDA DE PACOTES UTILIZANDO O PADRÃO IEEE 802.11ac

  • Data: 10/03/2017
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  • O fluxo de informação multimídia digital em redes sem fio tem crescido de forma exponencial, isso se deve ao fato da popularização dos padrões IEEE 802.11 como tecnologia de acesso, assim como no aumento de dispositivos (clientes) que operam neste padrão. O streaming de vídeo em altas resoluções também estão se tornando comuns nestas redes, impulsionando o desenvolvimento de CODECs cada vez mais eficientes. Neste contexto, algumas métricas de QoE e QoS devem ser atendidas para entregar um conteúdo com qualidade ao usuário final. Esta dissertação estuda o comportamento do streaming de vídeo em rede sem fio utilizando o padrão IEEE 802.11ac operando na faixa de 5,2 GHz, o CODEC avaliado é o H.264/AVC para três resoluções. A partir de simulações de perdas de pacotes durante a transmissão de vídeo é desenvolvido uma estimativa de perda de PSNR para cada resolução, encontrando a relação da perda de qualidade de vídeo variando a resolução conforme às perdas de pacotes.

  • THIAGO DE ARAUJO COSTA
  • ANÁLISE DE DESEMPENHO DE CÓDIGOS CONCATENADOS EM CANAIS AWGN E COM MULTIPERCURSOS: UMA ABORDAGEM BASEADA EM TRANSMISSÃO DE VÍDEO EM 4K CODIFICADO EM H.264

  • Data: 10/03/2017
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  • Dentro do processo de transmissão digital, o canal de comunicação pode promover uma série de imperfeições na informação transmitida. Com a crescente demanda por uma maior qualidade na transmissão multimídia digital, várias tecnologias, como DVB-T (Digital Video Broadcasting Terrestrial) e DVB-T2 (Digital Video Broadcasting Terrestrial - 2nd Generation) foram desenvolvidas com o objetivo de diminuir as distorções promovidas pelo canal de comunicação para possibilitar uma maior qualidade do serviço para o usuário. Dentro desse contexto, as técnicas de codificação de canal tem grande importância pois possibilitam transmitir a informação com uma menor probabilidade de erro possível. Assim torna-se importante avaliar o desempnho dos codificadores de canal. Esta disertação tem como objetivo realizar uma análise comparativa dos codificadores concatenados de canal BCH-LDPC e RS-CONV, utilizados pela TV digital, definidos respectivamente pelos padrões DVB-T e DVB-T2, sobre os canais AWGN e canal com multipercursos Rayleigh tanto em termos da BER (Bit Error Rate) como em relação sinal-ruído de pico (PSNR: Peak Signal-to-Noise Ratio) e a que mede similaridade estrutural (SSIM: Structural SIMilarity).

  • WELTON VASCONCELOS ARAUJO
  • ANÁLISE DE HEURÍSTICAS DE IMPLANTAÇÃO DE HETNETs DENSAS

  • Data: 24/02/2017
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  • ANÁLISE DE HEURÍSTICAS DE IMPLANTAÇÃO DE HETNETs DENSAS

  • GABRIEL VIANNA SOARES ROCHA
  • SISTEMA INTELIGENTE DE SUPORTE A ANÁLISE DA QUALIDADE DA ENERGIA ELÉTRICA EM REGIME PERMANENTE

  • Data: 21/02/2017
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  • SISTEMA INTELIGENTE DE SUPORTE A ANÁLISE DA QUALIDADE DA ENERGIA ELÉTRICA EM REGIME PERMANENTE

  • RODRIGO GUIMARAES DE AZEVEDO
  • ANTENA DE GRAFENO COMPOSTA DE DIPOLO-ESPIRA PARA AUMENTO DA LARGURA DE BANDA

  • Data: 17/02/2017
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  • Este trabalho tem como objetivo apresentar uma antena de grafeno de banda larga na faixa do terahertz. A antena é definida por uma combinação de um dipolo retangular e uma espira circular, em que o dipolo é alimentado por uma fonte de tensão no seu gap. É utilizado o método dos momentos bidimensional (MoM-2D) com impedância superficial para análise numérica da antena. São investigadas a dependência da impedância de entrada, do coeficiente de reflexão e da largura de banda da antena em função da alteração da geometria e da variação do potencial químico da espira.

  • HUDSON AFONSO BATISTA DA SILVA
  • SIMULADOR DE UMA SUBESTAÇÃO ELÉTRICA PARA ENSINO DE PRINCÍPIOS BÁSICOS DE ELETRICIDADE

  • Data: 08/02/2017
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  • Este trabalho apresenta o projeto e implementação de um simulador, composto de uma parte em software e outra em hardware, para o auxílio do professor no ensino de princípios de eletricidade e operação básica de uma subestação, tendo como caso de uso a subestação da Eletronorte no município de Marabá localizada na região Sudeste do estado do Pará. Para o desenvolvimento do simulador foram utilizados em conjunto a plataforma Unity em 2D e um mini circuito utilizando Arduino. O Simulador passou por avaliações em sala de aula com alunos e com o professor e se mostrou uma ferramenta capaz de auxiliar ao ensino de princípios básicos de eletricidade e operação básica de uma subestação. 

  • MOISES FELIPE MELLO DA SILVA
  • MACHINE LEARNING ALGORITHMS FOR DAMAGE DETECTION IN STRUCTURES UNDER CHANGING NORMAL CONDITIONS

  • Data: 31/01/2017
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  • Engineering structures have played an important role into societies across the years. Manage and maintenance of such structures demand regular inspections, evaluations and controlling activities to derive the actual condition. However, these visual-based approaches still rely heavily dependent of qualitative evaluations, compromising the structural management and decision-making process. To avoid these problems, automated structural health monitoring systems appears as a natural research field, which aims to provide more reliable and quantitative information to the structural manager. Unfortunately, normal variations in structure dynamics, caused by operational and environmental conditions, can mask the existence of damage. In SHM, data normalization is referred as the process of filtering normal effects to provide a proper evaluation of structural health condition. In this context, many research efforts have been carried out to the development of machine learning algorithms to deal with normal variations and expose structural anomalies from time response data. Particularly, the approaches based on principal component analysis and clustering have been successfully employed to model the normal conditions of structures, even when severe effects of varying normal conditions impose difficulties to the damage detection. However, these traditional approaches imposes serious limitations to deployment in real-world monitoring campaigns, mainly due to the constraints related to data distribution and model parameters, as well as data normalization problems. This work aims to apply deep neural networks and propose a novel agglomerative cluster-based approach for data normalization in an effort to overcome the limitations imposed by traditional methods. Regarding deep networks, the employment of new training algorithms provide models with high generalization capabilities, able to learn, at same time, linear/nonlinear influences. On the other hand, the novel cluster-based approach does not require any input parameter, as well as none data distribution assumptions are made, allowing its enforcement on a wide range of applications. These novel algorithms are implemented in an outlier detection strategy to perform data normalization and damage detection using only measurements from baseline conditions. The superiority of the proposed approaches over state-of-the-art ones is attested on standard data sets from monitoring systems installed on two bridges: the Z-24 Bridge and the Tamar Bridge. Both techniques revealed to have better data normalization and classification performance than the alternative ones in terms of false-positive and false-negative indications of damage, suggesting their applicability for real-world structural health monitoring scenarios.

  • DHONNY LIMA DA SILVA
  • UMA METODOLOGIA PARA ENQUADRAMENTO TARIFÁRIO EFICIENTE, POR MEIO DE ANÁLISE DA DEMANDA E DO CONSUMO DE ENERGIA ELÉTRICA: UM ESTUDO DE CASO NAS UNIDADES DA UNIVERSIDADE FEDERAL DO SUL E SUDESTE DO PARÁ 

  • Data: 25/01/2017
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  • No atual contexto mundial de avanços tecnológicos em que a sociedade se torna cada vez mais dependente da energia elétrica, um fato interessante chama atenção, o desperdício de energia elétrica nas instituições geradoras do conhecimento técnico e cientifico, Instituições de Ensino Superior- IFES, fato comprovado pela preocupação e iniciativa da Agência Nacional de Energia Elétrica-ANEEL publicada em  outubro de 2016 através chamada 01/2016 as concessionários distribuidoras de energia elétrica, que visa entre outros objetivos investir em eficiência energética e minigeração nas IFES, o que evidencia a ausência de gestão estratégica energética, a falta da cultura de otimização dos recursos energéticos e de recursos públicos e o descomprometimento com o uso sustentável de energia elétrica e como consequência dos recursos naturais por parte da maioria das IFES. Assim este trabalho poderá ajudar na busca pela minimização dos desperdícios com energia elétrica e dos recursos públicos nas IFES, à medida que irá propor uma metodologia de eficiência energética capaz de avaliar e ajustar o consumo de energia elétrica dos grupos A4 e B3 aos regulamentos vigentes. A metodologia consiste em alcançar a eficiência energética, por meio da análise da demanda, enquadramento tarifário e do consumo de energia elétrica, nas unidades  consumidoras das IFES, em especial ao estudo de caso das unidades da Universidade Federal do Sul e Sudeste do Pará (UNIFESSPA), através da análise das faturas mensais de energia elétrica e do embasamento das resoluções e normas sobre os tipos de tarifações de energia elétrica dos grupos A4 e B3, aplicadas pela ANEEL, respeitando também o estudo de caso que ocorrerá na aérea de concessão das Centrais Elétricas do Pará (CELPA). A metodologia também fará a fina previsão de demanda contratada – kW, para que se possa contratar a demanda que de fato se precise, evitando desperdícios. Com isso espera-se ajustar a demanda contratada de carga (kW) de cada unidade consumidora do grupo A4 a serem estudadas, a sua real necessidade, evitando custo desnecessários com pagamentos de demanda contratada acima ou abaixo da demanda consumida, objetiva-se também adequar o enquadramento tarifário de cada unidade consumidora a ser estudada, tanto do grupo A4 como B3, de acordo com sua demanda de carga e de seu consumo de energia elétrica e por fim almeja-se a redução de custo para a Administração Pública, através do consumo sustentável e de contratos eficientes de energia elétrica.

  • RANGEL FILHO TEIXEIRA
  • Game Marabá: Projeto, Implementação e Avaliação de um Jogo Educativo para Auxílio no Ensino de Estudos Amazônicos.

  • Data: 20/01/2017
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  • Para que o processo de ensino e aprendizagem tenha êxito, se faz necessário um alto grau de motivação para que se tenha um intenso envolvimento por parte dos alunos. Com gráficos que simulam a realidade, jogos para ensino geralmente são uma forma dinâmica, interativa e divertida de transmitir conteúdo para quem joga independentemente da idade. Onde é possível desenvolver ainda mais habilidades cognitivas, sociais, afetivas e culturais. Neste contexto o presente trabalho apresenta um jogo educacional 3D desenvolvido em terceira pessoa com tema histórico sobre a fundação da cidade de Marabá-PA, e o ciclo do caucho, seu primeiro ciclo econômico. É descrito como o roteiro foi construído a partir de um enredo criado com base na historiografia do evento, em que se procura enfatizar o lúdico. O jogo foi idealizado para ser uma ferramenta auxiliar da disciplina Estudos Amazônicos, que faz parte da grade curricular do 8º ano do ensino fundamental das escolas do estado do Pará; e foi experimentado e avaliado por três turmas de uma escola pública, obtendo resultados bastante positivos.

  • MARIA ELIANE SOBRINHO
  • Game Serra Pelada: Projeto, Implementação e Avaliação de um Jogo Educativo para o Ensino de Geometria para alunos do 9º Ano do Ensino Fundamental

  • Data: 20/01/2017
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  • Este trabalho apresenta a implementação e avaliação de um jogo de plataforma educativo, a proposta do projeto é
    utilizar os conceitos de geometria utilizando a Matriz de Referência de Matemática da 9º ano do ensino Fundamental: com o tema I; Espaço e forma. Tendo como cenário do jogo o garimpo de Serra Pelada, no enredo o personagem principal é um garimpeiro que luta com garimpeiros inimigos que tentarão impedi-lo de conseguir completar seus objetivos. O jogo serra pelada ao mesmo tempo em que ensina conceitos geométricos é divertido, o que o distingue se comparado com a grande maioria dos jogos educativos de matemática que carecem de ludicidade. Para verificar a aplicabilidade do jogo como ferramenta auxiliar no ensino de matemática, foram realizados os testes com alunos do 9° ano do ensino fundamental de uma escola pública no município de Marabá-Pa. O jogo foi bem aceito pelos estudantes e a avaliação comprovou que o software pode ser utilizado como ferramenta para auxiliar no processo de ensino e aprendizagem da geometria.

  • RICARDO MARINO KUHL
  • Geração de Energia Elétrica a partir dos Resíduos do Processo de Beneficiamento do Óleo de Palma: Uma Abordagem Sustentável para a Recuperação de áreas degradadas no Estado do Pará

  • Data: 16/01/2017
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  • A nova ordem mundial elenca como primordial a adoção de uma ótica diferente acerca do consumo e da geração de resíduos, além da preocupação acerca do meio ambiente. Devido a ascensão deste debate o modelo de desenvolvimento vigente tem sido questionado, principalmente no que diz respeito à irresponsabilidade, acerca da exploração dos recursos naturais. Dentro deste viés, a proposição realizada nesta dissertação, gira em torno da utilização de áreas degradadas, no estado do Pará, para o cultivo de dendê. A análise realizada abordou o balanço de emissões de dióxido de carbono (CO2) durante o ciclo produtivo do dendê, assim como o potencial de geração de energia elétrica através do efluente líquido, oriundo do processo de extração de óleo de palma bruto. Concernente as emissões de CO2 o presente trabalho constatou que a dendeicultura, tem potencial de redução variável de 180 a 500 milhões de toneladas de CO2eq, para a área estudada. Já o potencial de geração de energia elétrica verificada a partir da digestão anaeróbia do efluente líquido varia de 9.668,24 a 24.170,6 GWh durante o ciclo produtivo do dendê.

  • BRUNA CHAVES BRASILEIRO
  • Análise de um Modelo Energético baseado no uso da Biomassa Residual Local em comunidades isoladas no entorno da UHE de Tucuruí, Pa

  • Data: 16/01/2017
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  • Análise de um Modelo Energético baseado no uso da Biomassa Residual Local em comunidades isoladas no entorno da UHE de Tucuruí, Pa

  • RICARDO DE ANDRADE SHINKAI
  • Um Simulador para Avaliação da Influência das Características Locais das Descargas Atmosféricas Nuvem-Solo em Sistemas de Detecção Indireta

  • Data: 10/01/2017
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  • Um Simulador para Avaliação da Influência das Características Locais das Descargas Atmosféricas Nuvem-Solo em Sistemas de Detecção Indireta

2016
Descrição
  • LEONARDO LIRA RAMALHO
  • Compressão de Sinais LTE para Redes 4G/5G em Arquitetura C-RAN

  • Data: 20/12/2016
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  • As redes de acesso de rádio centralizadas, as chamadas C-RAN (cloud radio access network), criam um novo paradigma de célula, com pequenas áreas de cobertura e com várias células distribuídas em maior densidade. Nas redes C-RAN, a unidade que realiza o processamento digital de siansi, chamada de BBU (baseband unit), está distante da unidade que realiza o condicionamento do sinal analógico, chamado de RRH (remote radio head), de modo que as amostras digitais, as quais estão em banda base, precisam ser transportadas em altas taxas entre a BBU e o RRH, através do enlace chamado de fronthaul. Esta tese propõe um novo método para compressão das amostras digitais LTE, de modo a avaliar os severos requisitos de taxa de transmissão impostos ao fronthaul. O método proposto é baseado em predição linear e codificação por entropia. A combinação dessas técnicas resultou em um codec com baixo custo computacional e baixa latência. Além disso, o método proposto apresenta níveis de compressão e distorções competitivos com o estado da arte. Por exemplo, o codec pode ser configurado para fornecer um fator de compressão de 3:1 e EVms (error vector magnitude) tão baixas quanto 1%.

  • SEBASTIAO BORGES FONSECA
  • Alocação Ótima de Parques Eólicos em Sistemas de Distribuição considerando incertezas de vento e carga utilizando Algoritmo Genético

  • Data: 19/12/2016
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  • Alocação Ótima de Parques Eólicos em Sistemas de Distribuição considerando incertezas de vento e carga utilizando Algoritmo Genético

  • FABIOLA GRAZIELA NORONHA BARROS
  • Metodologia para Compressão de Sinais de Energia Elétrica a partir de Registros de Forma de Onda utilizando Algoritmos Genéticos e Redes Neurais Artificiais

  • Data: 16/12/2016
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  • Metodologia para Compressão de Sinais de Energia Elétrica a partir de Registros de Forma de Onda utilizando Algoritmos Genéticos e Redes Neurais Artificiais

  • ANDRE LUIS CARVALHO SIQUEIRA
  • Reconhecimento de Atividades Humanas utilizando Redes Neurais Auto-Associativas e Dados de Smartphone

  • Data: 16/12/2016
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  • Reconhecimento de Atividades Humanas utilizando Redes Neurais Auto-Associativas e Dados de Smartphone

  • FABIO DE OLIVEIRA TORRES
  • Mitigação de Interferência em Redes de Próxima Geração utilizando Técnicas de Clusterização e de Inteligência

  • Data: 16/12/2016
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  • Devido ao sucesso das redes de banda larga e ao crescente uso dos smartphones, as operadoras de telefonia móvel estão em busca de oferecer o mesmo padrão dos serviços das redes cabeadas aos usuários das redes sem fio e desta forma, novas tecnologias surgiram, dentre elas as Small Cells. Estas são pequenas estações rádio base que, em relação as macro-células, apresentam um custo muito inferior, oferecem um baixo consumo de energia, haja vista seu trabalho com baixas potências, mas por razão desta última caraterística oferece um espaço de cobertura bem menor. Por isso, em uma cenário onde uma grande quantidade deste equipamento será instalada, geralmente denominado DenseNets ou redes densas, e esta implementação não for realizada com base em um planejamento adequado, inúmeros problemas podem surgir, dentre eles a interferência co-canal, que em algumas situações, inviabiliza qualquer tipo de troca de informações. Por este motivo o modelo proposto nesta pesquisa pretende auxiliar os analistas de projetos e arquitetos de soluções no planejamento de redes densas oferecendo, a partir das informações sobre as localizações das Small Cells, quais serão as faixas de frequências adequadas ao uso de cada uma, a fim de que as novas aplicações, suportadas pelos smartphones, não sofram uma degradação de sinal a ponto de que suas funções não sejam executadas e haja um aumento na qualidade dos serviços que são oferecidos aos usuários destas redes. Nos testes realizados, o modelo apresentou uma melhora no tráfego em mais de 80% das Small Cells, reduziu o valor do atraso dos pacotes comutados e ainda colaborou para a diminuição do número de pacotes descartados. Não obstante, também analisou-se o desempenho dos módulos de bateria dos dispositivos móveis quando o modelo foi empregado e percebeu-se que ele não aumentou o consumo de bateria destes equipamentos.

  • JOSE GRACILDO DE CARVALHO JUNIOR
  • Métodos de Identificação Fuzzy para Modelos Autoregressivos Sazonais Mediante a Função de Autocorrelação Estendida.

  • Data: 13/12/2016
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  • Neste estudo, é proposta uma estratégia baseada na metodologia fuzzy, para a melhoria do desempenho das previsões de dados mediante um modelo de série temporal. Esta metodologia é concebida para modelagem de processos autoregressivos sazonais de média móvel e pode ser adotada sobr diversas aplicações no mundo real. Por meio da abordagem híbrida, baseada em uma versão da função de autocorrelação fuzzy, a interpolação e as capacidades de generalização de sistemas fuzzy foram exploradas, a fim de obter uma precisão robusta, mesmo considerando séries de baixa ou alta duração. A fim de aumentar a precisão do algoritmo de identificação proposto, vários parâmetros de desempenho foram testados e optimizados por testes computacionais. Os seguintes parâmetros foram considerados neste processo: o comprimento de trajetória da série histórica, o número de conjuntos fuzzy, o limite para ativação do suporte dos conjuntos fuzzy triangulares. Observou-se que a função de pertinência triangular contribuiu, para a melhoria do desempenho no modelo de previsão. Simulações para avaliar a precisão da rotina de identificação dos modelos autoregressivos fuzzy foram realizadas. Para demonstrar a eficácia da metodologia proposta, foram implementados quatro estudos de caso a partir de dados disponíveis na literatura. Os resultados confirmaram o bom desempenho do algoritmo proposto, permitindo a obtenção de um erro de previsão pequeno, sobre tudo, em comparação com metodologias de identificação paramétricas consolidadas na literatura. As projeções produzidas pelo novo método proposto, quando submetidas ao conceito de intervalo de confiança fuzzy, demonstraram uma precisão satisfatória.

  • DENIS CARLOS LIMA COSTA
  • Despacho Ótimo de Redes Integradas de Energia Elétrica e de Gás Natural com Restrições de Segurança Via Árvores de Decisão.

  • Data: 07/12/2016
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  • Esta Tese propõe um método de despacho seguro baseado em Árvores de Decisão (AD) aplicado em Redes Integradas de Energia Elétrica e de Gás Natural (RIEEGN) com contingências plausíveis que podem causar violações. Ajustes preventivos para a geração de energia elétrica e produção de gás natural ótimos são realizados com base nas regiões de segurança e limites de variáveis de controle determinadas pelas ADs. As regras da AD que descrevem as regiões de segurança são facilmente interpretáveis como restrições que garantem a segurança dos sistemas das RIEEGN, podendo ser incluídas nas rotinas de otimização de energia elétrica e reescalonamento da produção de gás natural. Algumas contingências críticas específicas foram aplicadas ao sistema de tese 118-bus IEEE integrado com a rede de gás natural 15-nós. Tais contingências são tomadas como exemplos para demonstrar uma aplicação promissora do método de despacho seguro proposto para restaurar a segurança das RIEEGN.

  • MANOEL HENRIQUE REIS NASCIMENTO
  • Uma Nova Solução para a Otimização do Despacho Econômico e Ambiental utilizando Metaheurísticas da Computação Bio-Inspirada

  • Data: 02/12/2016
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  • Esta Tese apresenta como proposta a implementação e análise de técnicas computacionais, baseadas em algorítmos evolucionários, que sejam apropriados para a solução de problemas de otimização aplicados ao Despacho Econômico de Carga (DEC) e ao Despacho Econômico de Emissões e Carga (DEEC) em usinas Termoelétricas (UTEs). Neste sentido, inicialmente, o presente texto apresenta uma descrição dos processos de eficiência energética e exergética de motores à combustão interna, os quais serão utilizados neste trabalho, e formula o problema de otimização do Despacho Econômico de Carga baseado em diversas técnicas da Computação Evolutiva para a resolução e análise dos processos termodinâmicos das UTEs. Na sequencia, formula-se o problema de otimização multiobjetivo em nível computacional para ser resolvido com foco na utilização de alguns tipos de algoritmos evolutivos (Algoritmo Genético de classificação não-dominado II - NSGA - II), propondo-se assim, ações para a aplicação das ferramentas desenvolvidas na solução de casos práticos, baseados até o presente momento, em problemas de despacho econômico de carga. Pretende-se na sequência do desenvolvimento da tese de doutorado introduzir a questão relativa às emissões.

  • JUAN FERREIRA VIDAL
  • Metaheurísticas Populacionais: Estudo Comparativo na Sintonia de Parâmetros de Controladores Clássicos

  • Data: 02/12/2016
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  • As metaheurísticas populacionais são técnicas pertencentes ao campo da Inteligência Computacional baseadas em modelos naturais e surgiram como alternativas para resolver problemas de otimização, onde as técnicas tradicionais não podem ser aplicadas, ou ainda onde não se dispõe de um modelo de solução para o problema, fazendo com que a solução seja encontrada por intermédio de meios empíricos. Diante da capacidade de oferecer soluções aceitáveis, em um tempo hábil, para muitos dos problemas complexos encontrados, as metaheurísticas populacionais vêm sendo aplicadas com êxito diferentes problemas de sistemas de controle encontrados na literatura. Este trabalho apresenta, de um modo geral, como as metaheurísticas vêm sendo aplicadas na solução de problemas de controle e realiza um estudo comparativo de desempenho entre quatro algoritmos bioinspirados na sintonia dos parâmetros de um controlador Proporcional-Integral-Derivativo (PID). Foram utilizados os seguintes algoritmos: Algoritmo Genético (AG), Algoritmo genético no Modelo de Ilhas (AGMI), Bacterial Foraging Optimization (BFO) e o Particle Swarm Optimization (PSO). Os resultados demonstram que os algoritmos apresentam um ótimo desempenho para a sintonia do PID, produzindo resposta que atendem as exigências de projetos. Foram utilizados diferentes sistemas com características distintas para avaliar os algoritmos. Considerando os resultados obtidos, o PSO se mostrou como o melhor algoritmo entre os quatros usados, produzindo resposta em um tempo mais rápido e apresentando menor desvio padrão nos ensaios realizados.

  • FITERLINGE MARTINS DE SOUSA
  • Análise Teórica de Filtros em estruturas EBG e em Guias de Ondas de Cristais Fotônicos

  • Data: 25/11/2016
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  • Este trabalho apresenta uma análise teórica de filtros utilizando estruturas Eletromagnetic Bandgap (EBG) e Guias de Ondas de Cristais Fotônicos. Em comparação com filtros convencionais, filtros com estruturas EBG tem melhores características de banda de rejeição na faixa de microondas. Na estrutura de filtro são feitos furos no plano terra e posteriormente esses furos terão o seu diâmetro alterado visando melhorar a qualidade da banda de rejeição e a obtenção de duas bandas de rejeição. Já no guia de ondas de cristais fotônicos são feitos defeitos na estrutura visando obter resultados no regime diferente de operação, neste caso no regime óptico. As referidas simulações foram feitas com o software comercial Ansoft HFSS para a estrutura EBG e Comsol para o guia de ondas de cristais fotônicos. Os efeitos dos parâmetros físicos das estruturas em relação a características de filtragem são estudados em ambos os filtros. Os resultados do procedimento de criação e de simulação são descritos e possíveis aplicações dessas estruturas de filtro são discutidas neste trabalho. A faixa de rejeição particularmente ampla é alcançada pelos circuitos apresentados neste trabalho bem como dupla banda de rejeição.

  • BILLY ANDERSON PINHEIRO
  • Uma Abordagem SDN para Virtualização de Redes

  • Data: 25/11/2016
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  • As Redes Virtuais De nidas por Software (virtual SDN networks - vSDNs) surgiram da associação de virtualização e Redes De nidas por Software (Software-De ned Networking - SDN), proporcionando maior controle e melhor utilização dos recursos de rede. Varios trabalhos ja mostraram a viabilidade e benefícios dessa abordagem. No entanto, o tema ainda carece de soluções que possam virtualizar uma rede de forma escalável, intuitiva e simpli cada. Desta forma, esta Tese propõe uma abordagem SDN para a virtualização de redes com o objetivo de reduzir as limitações em vSDNs. Sendo assim, sugere-se adotar na virtualização de rede a separação entre planos de dados (distribuído) e
    controle (centralizado), visão global da rede e uso de abstração de fluxo para gerir a comunicação entre os diferentes pontos. Para sustentar nossa proposição, três soluções foram desenvolvidas: o CIM-SDN (Common Information Model for Software-De ned Networking), para viabilizar o uso de representação formal dos novos elementos das vSDNs; o NVP (Network Virtualization Proxy), para prover maior escalabilidade atraves da separação do plano de controle em partes centralizadas e descentralizadas; e o GVL (Graph Virtualization Layer), para fornecer maior uso de abstrações entre o hypervisor e os controladores simpli cando, assim, o entendimento e uso da rede. Foram realizadas provas de conceitos para as três soluções propostas, demonstrando a viabilidade da abordagem.

  • FLAVIANO RAMOS PEREIRA JUNIOR
  • Redes Neurais Diretas e Recorrentes na Previsão do Preço de Energia Elétrica de Curto Prazo no Mercado Brasileiro

  • Data: 11/11/2016
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  • Nos estudos sobre o Mercado de Energia do Brasil existem poucos trabalhos sobre predição do preço de energia elétrica em curto prazo. Os que existem utilizam modelos preditores do tipo ARIMA e Rede Neural Direta, entretanto com a rede neural sem método de seleção das variáveis de entrada ou dos atrasos das entradas. Este artigo apresenta o uso de redes neurais diretas e recorrentes para a previsão do preço de energia elétrica de curto prazo brasileiro com uso da técnica de correlação para seleção das variáveis de externas da rede e também para escolha dos atrasos nestas variáveis selecionadas. Mostra-se que, na previsão um passo a frente, a rede direta supera o desempenho da rede recorrente para esta série, além disso, a seleção dos atrasos nas variáveis de entrada pode melhorar o desempenho da rede direta.

  • LIVIANE PONTE REGO
  • Estratégia para Predição de Consumo de Energia Elétrica de Curto Prazo: Uma abordagem baseada em densificação com Mean-Shift para tratamento de Outliers

  • Data: 04/11/2016
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  • Estratégias de predição de curto prazo é uma importante ferramenta usada para planejamento e operação de Sistemas Elétricos, bem como fundamentais para o processo de suporte à decisão para compra e venda de Energia Elétrica no mercado futuro. Nesse sentido, como um caso particular, tem-se a predição de consumo em dias especiais (feriados, ou dias atípicos, por exemplo), que pode ser uma tarefa complexa, dado seu comportamento anormal, quando comparado à predição de consumo em dias comuns. Contudo, seu número reduzido de amostras dificulta o treino e validação adequados dos algoritmos de predição. Este trabalho propõe um modelo para predição de carga de curto prazo que utiliza a técnica Mean-Shift para estudo, tratamento e densificação dos valores de consumo em dias especiais, e algoritmos de Redes Neurais Artificiais e Regressão Linear Múltipla para predição. O modelo foi aplicado em um problema de predição de carga da Concessionária de Energia Elétrica da região Norte do Brasil, que resultou na melhoria da acurácia já obtida pelos métodos já utilizados pela Concessionária.

  • FRANSERGIO MARTINS CARVALHO
  • Uma Estratégia Ativa para Detecção de Ilhamento em Geradores Fotovoltaicos por meio de Injeção de Sinais de Teste

  • Data: 27/10/2016
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  • Uma Estratégia Ativa para Detecção de Ilhamento em Geradores Fotovoltaicos por meio de Injeção de Sinais de Teste

  • CASSIO ANDRE SOUSA DA SILVA
  • Correção de Apagamentos em Rajadas utilizando Códigos LDPC gerados pela Composição de Matrizes Bases e pelos Movimentos de Matrizes Circulantes

  • Data: 21/10/2016
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  • São propostos neste trabalho procedimentos para a construção de matrizes bases baseados na álgebra e na geometria. Essas matrizes bases servem de plataforma para gerar as matrizes cheque paridade na correção de erros em rajadas de códigos LDPC. É utilizado superposição nas matrizes bases e movimentos das matrizes clientes circulantes. É usada codificação de baixa complexidade e o algoritmo interativo soma-produto para mostrar os bons resultados das duas construções. Foram gerados vários códigos LDPC (matrizes) e os resultados obtidos comparados com outros códigos da literatura. Os códigos gerados foram aplicados na correção de apagamentos apresentando um bom desempenho.

  • DIEGO BRANCHES VILAR
  • Gerenciamento de Energia Residencial com Geração Fotovoltaica utilizando Recozimento Simulado

  • Data: 16/09/2016
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  • A evolução das redes tradicionais em redes inteligentes tem contribuído para o aumento da penetração da geração distribuída nos sistemas elétricos. Além disso, a maior integração da Tecnologia da Informação e Comunicação (TIC) com os Sistemas Elétricos de Potência (SEP) tem possibilitado o envolvimento do consumidor à gestão da demanda, que ganhou um interesse crescente nos últimos anos. Apesar de ser um tema discutido desde meados de 1980, somente com o advento das Redes Inteligentes o mesmo passou a ser mais difundido. Nesse sentido, o consumidor deve ter o conhecimento das estratégias de gerenciamento pelo lado da demanda (GLD) para poder tirar vantagem deste programa. Portanto, Esta dissertação de mestrado tem como objetivo desenvolver uma metodologia de gerenciamento de energia residencial (do inglês, Home Energy Management System - HEM), para auxiliar o cliente na tomada de decisões quanto ao deslocamento de carga fornecendo propostas de agendamento para o consumo de energia em residências, em resposta aos sinais tarifários, de modo a reduzir os gastos do consumidor com a compra de energia fornecida pela concessionária e otimizar o uso da geração fotovoltaica.

  • LEO CESAR PARENTE DE ALMEIDA
  • Obtenção e Análise da Performance de Portas Lógicas Totalmente Ópticas baseadas em Guias de Cristais Fotônicos

  • Data: 09/09/2016
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  • Nesta dissertação, foi utilizado o conceito de Cristais Fotônicos (PhCs) para a simulação numérica de duas portas lógicas totalmente ópticas, ou seja, portas NOT e NAND. Estas novas estruturas totalmente ópticas são compostas por um anel ressonador de cristal fotônico não linear (PCRR) em duas dimensões (2-D), feito de hastes dielétricas de silício (Si) no substrato de ar. O método da expansão em ondas planas (PWE) e o método das diferenças finitas no domínio do tempo (FDTD) são utilizados para analisar o comportamento destas estruturas. O método PWE é utilizado para calcular o intervalo de banda fotônica das estruturas de PhC, que é de 0,2654-0,3897 (/ λ). As redes quadradas das portas lógicas (NOT e NAND) fabricadas são implementares no comprimento de onda operacional igual a 1700 nm. Por serem baseadas em cristais fotônicos, são bastante compactas e podem ser projetadas em dimensões bastante reduzidas, contribuindo assim com a densidade de integração de componentes em sistemas de comunicações ópticas. Os resultados das simulações mostram que as estruturas propostas são potenciais candidatas para a concepção de circuitos ópticos digitais ultra-rápidos e altamente vantajosos com alto poder de transmissão, simples design, além de serem fortemente aplicáveis para a fabricação de circuitos integrados fotônicos, devido à sua simples estrutura e o seu claro princípio de funcionamento.

  • LIDIO MAURO LIMA DE CAMPOS
  • UMA METODOLOGIA BIOLOGICAMENTE INSPIRADA PARA PROJETO AUTOMÁTICO DE REDES NEURAIS ARTIFICIAIS USANDO SISTEMAS-L PARAMÉTRICOS COM MEMÓRIA

  • Data: 26/08/2016
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