Mestrado em Engenharia Elétrica e da Computação (EMC)
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Navegando Mestrado em Engenharia Elétrica e da Computação (EMC) por Por Orientador "Calixto, Wesley Pacheco"
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Item Atenuação das componentes oscilantes de conjugado no gerador síncrono de polos salientes(Universidade Federal de Goiás, 2018-08-30) Aleluia Junior, Leovir Cardoso; Alves, Aylton José; http://lattes.cnpq.br/2762752291082988; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Alves, Aylton José; Pinheiro Neto, Daywes; Domingos, José Luiz; Oliveira, Marco Antônio Assfalk deThe present work is devoted to the development of a methodology for attenuation of the electromagnetic conjugate oscillations using insertion of AC components added to DC components in the field excitation of the synchronous generator of outgoing poles submitted to non-sinusoidal voltage conditions. It is used mathematical modeling able to consider the effects of harmonic components of current and voltage and study is carried out on the oscillations of conjugate using computational simulations. The synchronous generator is connected to the bus and subjected to sinusoidal and non-sinusoidal voltage conditions with the insertion of linear and non-linear loads. It is verified that the conjugate oscillations are influenced by the insertion of nonlinear loads, inducing the periodic behavior, being the main components of the sixth order and their multiple. The results obtained reduce the oscillating electromagnetic torque components by approximately 50%.Item Metodologia de otimização de lentes para lâmpadas de LED(Universidade Federal de Goiás, 2013-06-14) Barbosa, José Luiz Ferraz; Brito, Leonardo da Cunha; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Brito, Leonardo da Cunha; Yamanaka, Keiji; Alves, Aylton José; Marra, Enes GonçalvesThe purpose of this work is to present a methodology for optimizing the geometry of the Light Emitting Diode (LED) secondary lens, in non-imaging applications, which focuses on the distribution of illuminance on a target plane. The simulation of Ray Tracing is produced by stochastic method and the optimization process based on heuristic search interacts with Ray Tracing to nd the optimized parameters of the LED secondary lens geometry.Item Controle inteligente para maximização da geração de potência em termogeradores(Universidade Federal de Goiás, 2019-03-29) Bezerra, Carlos Daniel de Sousa; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Naka, Marco Hiroshi; Alves, Aylton José; Pinheiro Neto, Daywes; Lemos, Rodrigo PintoThis work presents a theoretical and experimental analysis of the physical connection and intelligent control of DC-DC converters to the Seebeck thermoelectric generating system. The methodology is based on the application of heuristic optimization methods for the tuning of controllers, observing the transient and permanent responses. It is also developed methodology using artificial neural network associated with the control in voltage mode, necessary for the tracing of the maximum power of the thermogenerator. The computational mathematical model of voltage converter, thermogenerator, controller based on the place of roots, non-pre-phase systems and control techniques is described. The computational simulations and and the practical tests are validated. The results indicate the efficiency of the optimization methods in the tuning of the voltage controller and the best response times for neural networks as a mechanism for tracking the maximum power.Item Mineração de opinião em mídias sociais com aprendizado de máquina(Universidade Federal de Goiás, 2020-10-14) Brandão, Jhonathan de Godoi; Calixto, Wesley Pacheco; https://orcid.org/0000-0002-1928-4432; Calixto, Wesley Pacheco; Ribeiro, Luiz Eduardo Bento; Reis, Márcio Rodrigues da Cunha; Cruz Junior, Gelson da; Marques, Leonardo GarciaThe aim of this work is to develop a tool for that optimizes supervised machine learning models in order to classify polarity of opinions in tweets. Five different datasets are used, which are prepared, preprocessed and then used as input for the training and evaluation stage of machine learning models. The best accuracy results obtained in the training and evaluation of the models are 82.45% for the data without preprocessing × 78.83% with all the proposed preprocessing for the dataset using the Naive Bayes classifier. Finally, hyperparametric optimization of the classifiers and selection of the model that obtains the best accuracy is performed. The optimized model achieves an accuracy greater than 90% for some data sets. The supervised learning techniques depend on labeled data for training, the proposed method produces similar performances for datasets of varying sizes, which allows the development of optimized classification models with reduced amount of labeled data.Item Metodologia de previsão utilizando identificação de sistemas aplicada a séries temporais(Universidade Federal de Goiás, 2018-10-29) Bulhões, Júnio Santos; Calheiros, Débora Fernandes; http://lattes.cnpq.br/6343238272229162; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Calheiros, Débora Fernandes; Oliveira, Sérgio Botelho de; Pinheiro Neto, Daywes; Oliveira, Marco Antonio Assfalk deThis work proposes a methodology that uses spectral analysis and system identification in order to fill gaps in time series. The methodology proposes the implementation of predictions in time series of physical and chemical variables that are related with flood areas that are collected with no frequency. It is used predictive neural network with autoregressive model and classification neural network. Collected values are extracted from the original data set in order to later test and validate the proposed methodology. The results demonstrated the effectiveness of the methodology, which is able to predict the behavior of different variables using the previously recognized patterns in the time series.Item Processo de otimização aplicada na adequação de tensão utilizando geração distribuída fotovoltaica(Universidade Federal de Goiás, 2018-08-29) Cararo, José Alberto Gobbes; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Reis, Márcio Rodrigues da Cunha; http://lattes.cnpq.br/1167385371830496; Pinheiro Neto, Daywes; Gomes, Raphael de Aquino; Ribeiro, Luiz Eduardo Bento; Nerys, José Wilson LimaThis work presents methodology for voltage adequacy into electric power distribution network with the insertion of photovoltaic distributed generation. Deterministic, heuristic and hybrid optimization methods are used to find the variables: i) geographical siting, ii) supply power and iii) amount of photovoltaic distributed generation. The main characteristic of the methodology is the obtaining of the amount of photovoltaic distributed generation units necessary for the adequacy of electric network voltage, respecting the supply power of each generation unit. The results indicate improvement in voltage levels after insertion of photovoltaic distributed generation units with optimized parameters for different voltage transgression scenarios. The proposed methodology is efficient for voltage adequacy through the insertion of photovoltaic distributed generation.Item Sintonia de controlador preditivo não linear: análise comparativa com técnicas tradicionais(Universidade Federal de Goiás, 2017-11-20) Carvalho, Douglas Freire de; Ganzaroli, Cleber Asmar; http://lattes.cnpq.br/7006345437314171; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Ribeiro, Luiz Eduardo Bento; Oliveira, Eider Lúcio de; Nerys, José Wilson LimaThis work presents study of nonlinear predictive controller, tuned by optimization process, applied to independent excitation DC motor speed control, controlled by fully controlled three phase rectifier. The methodology starts from the construction of the workbench that represents the real system followed by the development and validation of the computational model. The optimization process promotes the obtaining of optimized parameters for the nonlinear model based predictive controller to be implemented in the real process. Comparisons are made between the control technique proposed with classical control techniques, in computational and real environment. The results indicate the prominence of the proposed technique to be used in control of non-linear systems where seeks smaller errors even with disturbance insertions.Item Implementação e análise das técnicas de controle por modos deslizantes e preditivo não linear(Universidade Federal de Goiás, 2018-08-31) Couto, Luiz Alberto do; Ganzaroli, Cleber Asmar; http://lattes.cnpq.br/7006345437314171; Calixto, Wesley Pacheco; http://lattes.cnpq.br/907347819202786This work presents an implementation and analysis of traction control and linear trepidation techniques, driven by a six - pulse fully controlled three - phase rectifier. The methodology addresses the construction of real reality, modeling by method of system identification, design and tuning of optimization processes. The comparisons between the techniques are their characteristics and their performances when performing statistics, verifying the robustness of the series in non-linear systems. Both techniques perform satisfactory in the execution of the control, correlating with the.Item Análise comparativa de técnicas de controle Fuzzy e matriz dinâmica aplicadas à máquina de corrente contínua(Universidade Federal de Goiás, 2017-11-27) Dias, Rafael Nunes Hidalgo Monteiro; Ganzaroli, Cleber Asmar; http://lattes.cnpq.br/7006345437314171; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Pinheiro Neto, Daywes; Siqueira, Ildeu Lúcio; Oliveira, Marco Antônio Assfalk deThis work presents a comparison between Fuzzy and dynamic matrix controllers. These controllers are applied to the direct current (DC) motor speed control, triggered by fully controlled three-phase rectifier. The construction of the real system and the development and validation of the computational model are described. The controllers’ parameters are obtained through an optimization process. Both control techniques are compared and results indicate better performance of the optimized controllers, which suggest their promise in nonlinear systems’ control, in which seeks out control without error, that fulfills well its duty and its able to resist the fatigues.Item Dispositivo para medição de impedância em sistemas de aterramento elétricos em alta frequência(Universidade Federal de Goiás, 2016-11-04) Ferraz, Rafael da Silva; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Paula, Samuel Cesar Mota; Alves, Aylton José; Nerys, José WilsonThis work presents the project and the implementation of a device that is capable of measuring the electrical effects, especially the impedance, in grounding meshes when subjected to atmospherical discharges. An analysis on the influence of the atmospheric discharges in electrical protection systems is performed and also a comparison between current and voltage impulsive circuits. The device is built of electronic circuits controlled by a microcontroller, with the possibility of parameter adjusting for shaping the generated impulse wave. The device was conceived such that it can be used for tests of soil impedance measurement and for verification of the behavior of electrical grounding systems under high frequencies. The results are presented for tests in different types of systems and there was satisfactory performance for the developed equipment when compared with a commercial deviceItem Desenvolvimento e validação de aparelho automático para medição da compactação do solo(Universidade Federal de Goiás, 2016-08-16) Furriel, Geovanne Pereira; Alves, Aylton José; http://lattes.cnpq.br/2762752291082988; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Alves, Aylton José; Silva, José Geraldo da; Oliveira, Marco Antônio Assfalk de; Narciso, Marcelo GonçalvesThe purpose of this work is to present the development of automatic instrument for measuring soil compaction through penetration resistance. Commonly, this measurement is performed by load cells. In the proposed methodology and apparatus, the penetration resistance is directly measured by the current applied to the motor that performs penetration of the rod into the soil, thus replacing the load cell. The collected data are stored in Datalogger and further processed in order to enable analysis and the generation of maps of the surface with soil compaction values up to a certain depth. The presented results indicate greater precision and control of the fundamental parameters of data acquisition.Item Processo de otimização aplicado em método descritivo da análise de dados(Universidade Federal de Goiás, 2018-02-21) Gomes, Flávio Adalberto; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Oliveira, Eider Lúcio de; Fonseca, Regina Célia Bueno da; Oliveira, Marco Antônio Assfalk deThis work presents methodology for construction and optimization of mathematical structures that represent experimental data. A hybrid optimization process between an heuristic method and a direct search deterministic method is used. Input and output values of real systems are used and some mathematical expressions are formulated to be used as test and validation. The results are compared with traditional methods, analyzing the oscillations at the edges. The proposed method presents a feasible solution for experimental data analysis and extrapolation, with reduced mathematical expressions.Item Geometria de dutos de escape otimizada para aplicação na cogeração da produção de energia elétrica(Universidade Federal de Goiás, 2017-12-05) Gomes, Pedro Henrique Garcia; Alves, Ayton José; http://lattes.cnpq.br/2762752291082988; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Alves, Ayltom José; Domingues, Elder Geraldo; Oliveira, Eider Lúcio de; Oliveira, Maco Antônio Assfalk deThe objective of this work is to seek greater efficiency in energy conversion using the Seebeck modules, from the duct geometry optimization exhaust hot gases. Different materials and geometries are tested. The duct thickness was varied along the longitudinal fluid flow and optimized parameters are obtained heuristically . After the development of optimized duct model, a prototype is built for testing in the actual system. From the resistive air layer, the surface temperature gradient equalization is obtained, improving the efficiency of the system.Item Identificação do grau de comprometimento neurossensório-motor utilizando tempo de resposta(Universidade Federal de Goiás, 2017-01-16) Klafke, Marcelo; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Diniz, Denise Sisterolli; Gervásio, Flávia Martins; Oliveira, Marco Antonio Assfalk de; Cruz Junior, Gelson da; Calixto, Wesley PachecoThis work proposes the development of the evolution scale for neurosensory-motor pathology through a statistical approach and the use of response time tests. Reference data are collected in two groups: i) individuals are affected and ii) individuals are not affected with Multiple Sclerosis. A portable metering device is developed with the differential of measuring simple and choice response times for upper and lower limbs with the use of auditory and visual stimuli. A method is proposed to evaluate the effectiveness of the rehabilitation process of patients with neurosensory-motor impairment through standardized quantitative measures that aid in clinical decisions and treatment. The result of the proposed method is the multidimensional graph consisting of competing axes formed by normalized scales between 0% and 100% that indicate the level of neurosensory-motor impairment assessed from the response time data. The data distribution is analyzed using the maximum likelihood method, descriptive statistics and the use of the scale and graph model proposed is demonstrated and compared with the Kurtzke Expanded Disability Status Scale in Multiple Sclerosis patients.Item Dispositivo para ensaio automático de sedimentação e análise granulométrica do solo(Universidade Federal de Goiás, 2018-12-14) Martins, Daniel Warles Pereira; Damin, Virgínia; http://lattes.cnpq.br/7413922413797454; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Damin, Virgínia; Damasceno, Deangelis; Kliemann, Huberto José; Silva, José Geraldo daThis work presents a device and method for the recognition of soil physicochemical properties. The proposed device measures the behavior of the particles in sedimentation using the principle of photo sedimentation in multipoints. For each soil submitted to the test in the device, a matrix is generated that corresponds to the behavior of the soil. This matrix is submitted to pattern recognition using artificial neural network, which identifies the soil type and by association in the database, presents the best classification for the soil tested. The results show that the measurements carried out in the multipoints provide significant information on soil sedimentation behavior.Item Métrica de complexidade em sistemas a eventos discretos(Universidade Federal de Goiás, 2016-04-27) Paiva, João Ricardo Braga de; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Domingues, Elder Geraldo; Yamanaka, Keiji; Cruz Júnior, Gélson daThis work presents metric for complexity calculation in discrete event systems. The proposed methodology uses the dynamics of the system taking into account their active connections, mapped in relationship matrix. The complexity metric is applied to three distinct systems. The results show the relationship between the complexity and specic characteristics of each system. The proposed method combines knowledge about the system, contributing to behavior and performance analysis.Item Cálculo de parâmetros de malhas de aterramento em geometrias não convencionais(Universidade Federal de Goiás, 2016-03-28) Pires, Thyago Gumeratto; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Visacro Filho, Silvério; Alves, Aylton José; Nerys, José Wilson LimaThis work presents the methodology for the calculation of the ground resistance, the ground potential rise, the surface potential, the touch voltage and step voltage in grounding grids with any geometry and buried at any depth within strati ed soil in two layers. The values of potential, touch voltage and step voltage are obtained at any point over the grid. The proposed equation uses the images and the average potential methods. The main feature of this modeling in relation to the other methods is the possibility of calculation of grids containing electrodes positioned at any distance and at any angle. The results obtained with the proposed methodology are presented and discussed.Item Corinda: heurísticas concorrentes para quebra de senhas(Universidade Federal de Goiás, 2018-08-27) Rodrigues, Bernardo Araujo; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Sousa, Marcos Antônio de; Boaventura, Ricardo Soares; Fonseca, Regina Celia Bueno da; Lemos, Rodrigo PintoThis work proposes the development of a software with the purpose of cracking passwords based on concurrent heuristic algorithms, first order model theory and statistical inference. The proposed methodology is developed on the Go programming language, with focus on communicating sequential processes. The software uses concurrent heuristic algorithms based on statistical patterns derived from sample sets to perform password cracking. Distinct statistical distributions are detected on sample sets. The software is able to crack significant portions of three diferente password sets in short periods of time. It is concluded that concurrent heuristic algorithms are a viable alternative to perform Central Processing Unit password cracking and can be used to raise awareness amonsgt users about the importance of high entropy passwords and digital privacy.Item Otimização do atendimento médico-hospitalar emergencial utilizando sistema a eventos discretos(Universidade Federal de Goiás, 2016-06-17) Santos, Luciano Eduardo Braga dos; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Lima, Marcos Antônio Cardoso de; Domingos, José Luís; Oliveira, Marco Antônio Assfalk deThis work prop oses numerical metho d of simulation and optimization of waiting time in queues in hospital emergency. The case study is carried out in private hospital in the city of Goiania, Goias/Brazil. It is used to mo del discrete event systems as computational simulator and two optimization heuristics: the Brute Force algorithm and Genetic Algorithm. The optimization results are compared with the directives found in Resolution CFM 2077/2014, in an attempt to adapt the system to this resolution. With the results, it is observed that the simulation metho d and optimization metho ds are efficient to minimize queues at hospital emergency system.Item Metodologia para correlacionar a umidade, compactação e a condutividade elétrica aparente do solo(Universidade Federal de Goiás, 2014-12-19) Silva Filho, Antônio Marcelino da; Calixto, Wesley Pacheco; http://lattes.cnpq.br/9073478192027867; Calixto, Wesley Pacheco; Narciso, Marcelo Gonçalves; Alves, Aylton JoséThis work presents the study of the relationship between soil apparent electrical resistivity ρa and the moisture content, clay content and soil compaction, for use of the ρa as a mapping tool of spatial soil variability. The values of apparent electrical resistivity are obtained by geoelectrical prospecting methods that detect the effects produced by the flow of electrical current in the soil. It is used the Wenner array and the technique of Lateral Profiling for data collection. It was held measures of ρa in different soil types, varying moisture content gradually while maintaining a constant compaction, and then varying the compaction and relating it to a constant humidity. To the study of spatial variability, it was chose two areas that would enable the change of moisture and compaction content, in order to verify the measurement capacity of ρa as methodology of identification of change in soil dynamics. The results obtained are presented and discussed.