Programa de Pós-graduação em Engenharia Elétrica e da Computação

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Adaptabilidade temática em sistemas tutores inteligentes híbridos
(Universidade Federal de Goiás, 2008-02-23) QUINDERÉ, Pedro Sérgio Gomes; NALINI, Lauro Eugênio Guimarães; http://lattes.cnpq.br/7555089672749145; MARTINS, Weber; http://lattes.cnpq.br/3123848470517021
In the context of efficient information transmission among people and, particularly in the helping of learning and training processes, this investigation presents results on the use of the technology of Hybrid Intelligent Tutoring Systems, based on artificial neural networks and expert rules, developed by Martins [MEA 2004], Melo [MEL 2003] and Meireles [MEI 2003]. Due to the fact that, in its initial empirical validation, neural training data has been originated from courseware in Introduction to Data Processing , some doubts have remained on the applicability of the trained neural network to other scenarios. The present production has approached these issues by the formalization of the content format and by presenting promising empirical results in two other scenarios: Scientific Methodology and Biological Rhythms . Results were analyzed by non-parametric methods with 5% significance. They reinforce the hypotheses that the studied tutoring system is efficient, able to reduce differences of distinct groups and shows thematic adaptability actually
Aplicação do mapeamento conforme no cálculo do fator de Carter
(Universidade Federal de Goiás, 2008-06-06) CALIXTO, Wesley Pacheco; BRITO, Leonardo da Cunha; http://lattes.cnpq.br/6660680440182900; ALVARENGA, Bernardo Pinheiro de; http://lattes.cnpq.br/9850449311607643
The present work proposes a numeric formulation for the determination of Carter's factor as a function of the geometry of the slot of electric machines. This task is made by the use of the Schwarz-Christoffel transformation. In order to reach the objective, there is the need to calculate the Schwarz-Christoffel inverse transformation. This represents a non-linear optimization problem. Therefore, it is proposed a methodology to calculate the parameters of the Schwarz-Christoffel inverse transformation using genetic algorithms. The assessment of Carter s factor is achieved considering polygonal domains with many vertices. The transformation leads to a rectangular domain approach. Moreover, some case studies are proposed and the methodology results are compared to traditional formulation results for the Carter s factor, yielding some disparities.
Detecção Automática de Ondas de Elliott em Mercado Acionário
(Universidade Federal de Goiás, 2008-08-06) CALAÇA, Raul Wonsjuk; MARQUES, Thyago Carvalho; http://lattes.cnpq.br/1763926064124591; MARTINS, Weber; http://lattes.cnpq.br/3123848470517021
The Elliott Wave analysis is a technique developed for the prediction of prices of financial assets (stocks, exchange rates etc.). This work introduces the basic concepts of the financial market, focusing mainly on the Elliott Wave principle, which differs from other techniques for providing direction and intensity of changes in shares / stocks prices in the financial market. The Elliott Wave detection usually employs manual methods, since automated systems present high costs and are apparently based on trial and error method associated with Statistics. Manual methods assess, following some rules, the waves prospected by trial and error, and requires specialized training and experience. To automatically detect the waves of Elliott, this work suggests, develops and tests a computational system based on Genetic Algorithms, an Artificial Intelligence technique inspired on Biology. Genetic Algorithms are used to evolve answers to problems by assessing candidates, which are coded as chromosomes. Tests of the system were performed based on BM&FBOVESPA stocks with high daily liquidity. Simulations have indicated that the detected waves are satisfactory, with error rate below 3% in each inflection point.
Falhas e defeitos ocorridos em transformadores de potência do sistema elétrico da Celg, nos últimos 28 anos: um estudo de caso
(Universidade Federal de Goiás, 2008-08-20) SOUZA, Denise Cascão Poli; RIBEIRO, Cacilda de Jesus; http://lattes.cnpq.br/8998911644222586
Power transformers have a fundamental role in an electrical power system, in addition to representing a significant amount of investment required for the implantation of this system. To reduce the costs associated with a transformer s life cycle and to guarantee its reliability and durability, it is essential to monitor its operating conditions, its insulation system as well as the working conditions of its accessories and other components. Therefore, the aim of this work is to study the faults and defects that occur in power transformers of 34.5kV, 69kV, 138kV, and 230kV of Celg s electrical system, the latter being a highly important electric energy concessionaire in Goiás State, Brazil. The results of this study corroborate its contributions to the field, namely, the efficacy of the predictive technique in the maintenance area during the last twenty-eight years (from 1979 to 2007), the characterization of faults and defects during this period, and the presentation of proposals to implement improvements in the predictive technique, in order to reduce the number of interruptions in the electrical power system.
Utilização de um sistema de realidade virtual não imersiva como ferramenta para a reabilitação de membros superiores de indivíduos hemiparéticos
(Universidade Federal de Goiás, 2008-09-05) BARBOSA, Dagoberto Miranda; OLIVEIRA, Marco Antonio Assfalk de; http://lattes.cnpq.br/5601509957082902; SANTOS, Euler Bueno dos; http://lattes.cnpq.br/5005722083309404
ROTEAMENTO AUTOMÁTICO DE ALIMENTADORES NO PLANEJAMENTO DE SISTEMAS DE DISTRIBUIÇÃO DE ENERGIA ELÉTRICA
(Universidade Federal de Goiás, 2008-11-07) ROCHA, Adson Silva; BRITO, Leonardo da Cunha; http://lattes.cnpq.br/6660680440182900
The present work deals with the problem of planning the distribution system of electricity and is divided into three parts: Problem Definition, Resolution Approaches and Results and Conclusions. The energy distribution networks are of great economic importance in countries like Brazil. On one hand, there are fixed costs of physical installation and operation of the network, mainly due to the costs of energy losses and, secondly, the natural obstacles along the possible passages of network s links. The large amount of these costs, together with lack of efficient methods when it comes to real applications in the matter, justify the development of this research. The study of such aspects, the precise definition of the problem and the reasons that motivated this work can be found on the first part of this work. The second part shows the approaches for resolution. Three proposals methods were adopted: the first uses the algorithm Prim associated with the method Nelder-Mead Simplex. In the second proposal uses Dynamic Programming and, finally, we take the metaphor of Ant Colony also associated with the Nelder-Mead Simplex. The results, presented at the third part of this work, demonstrated the effectiveness of the proposed methods, especially the good compromise between performance and applicability obtained by the third proposal.
Análise e Comparação de Modelos de Previsão de Vazões para o Planejamento Energético, Utilizando Séries Temporais
(Universidade Federal de Goiás, 2009-01-02) XAVIER, Priscila Branquinho; CRUZ JÚNIOR, Gélson da; http://lattes.cnpq.br/4370555454162131
n the planning of the energetic operation, analysis and forecasts of the flow are very important. A huge difficulty in the forecast of flow is the seasonality presence, due to drought and flood periods in the year. Many scientists, with different methodologies, have been concerned with finding a best model, compared with the utilized by Brazil s system - Markovian Model. The Makovian Model, or selfregressive with order 1, is a Box & Jenkins methodology, and requires data handling to treat non-stationarity, or the use of regular models, requiring a hardly theoretical formulation for the statistical procedures. Therefore, the statistical models, autoregressive model with seasonality and Holt-Winters model, of treatment of temporal series are presented and, carried out the flow s analysis and forecast for three study groups, in two different (historical) horizons. The performance of the models was compared and the results showed that the proposed models presents better adjust than the model adopted by Brazilian system
ANÁLISE ECONÔMICA E BALANÇO ENERGÉTICO DO BIOGÁS EM GRANJAS DE SUÍNOS
(Universidade Federal de Goiás, 2009-02-10) LIRA, João Carlos Umbelino; MARRA, Enes Gonçalves; http://lattes.cnpq.br/8463332056679918
This work presents a case analysis of energetic harnessing in a piggery, based on the use of biogas generated from pig sewage. The analysis shows that the energy from the biogas produced in the farm processes can be partially used through Clean Development Mechanisms (CDM) in order to improve the system efficiency. The utilized process presents environmental and economical benefits as carbon emissions are reduced and their credits can be traded. Moreover, an economic analysis of alternatives for biogas use was carried out taking into account technical, environmental and financial aspects. The case study was realized on a piggery farm in the south-west of the Goiás State where the economical viability of each of the presented alternatives was analyzed considering the following: total burning of biogas; generation of electrical energy; heating; or the combined heat and power generation (CHP).
Contribuições para regulamentação da tecnologia PLC no Brasil com base em testes de campo
(Universidade Federal de Goiás, 2009-02-27) MARQUES, Fabio da Silva; ARAÚJO, Sérgio Granato de; http://lattes.cnpq.br/3634204499080969
This work describes the data transmission technology called PLC (Power Line Communications) that demanded discussions in order to assess the potential for interference in services currently in operation and using radio frequency in the range of 1,705MHz to 30MHz The equipment used in this type of technology, and its principle of operation principle based on the field trials in indoor and outdoor environments are described. It is presented in this paper a case study about the influence caused in carrying on a network PLC because of electromagnetic interference. It was possible determining the noise influence from electricelectronic equipment in the performance of a network PLC and what types of equipment are more harmful to the communication. Finally some suggestions are pointing, as the use of mitigation techniques which technology has greatest potential for success by contributing to the regulation and standardization in Brazil
Redução da complexidade computacional do método de estimação de ângulos de incidência através da diferença entre os valores singulares da matriz de covariância espacial
(Universidade Federal de Goiás, 2009-03-13) SILVA, Hugo Vinícius Leão e; LEMOS, Rodrigo Pinto; http://lattes.cnpq.br/3333000136853156
This work is concerned with the estimation of Direction-Of-Arrival (DOA) angles of plane waves impinging on a sensor array. Among all methods of estimation found in litera-ture, MODEX (MODE with eXtra roots) outstands for its performance and computational complexity. However, recently, a method called SEAD (SEArch of Direction by differential spectrum) was proposed. It has shown better estimation performance against noise than MODEX has. However, its computational complexity is prohibitive for real-time applications. In order to reduce it s computational complexity, a new estimate selection procedure on SEAD is proposed, that yields to significantly less candidate angles than before. Additionally, the introduction of iterative refinements on estimates has allowed improving resolution as well as complexity reduction
Programação Genética Aplicada à Programação de Controladores Lógico Programáveis
(Universidade Federal de Goiás, 2009-05-29) CARNEIRO, Marcos Lajovic; BRITO, Leonardo da Cunha; http://lattes.cnpq.br/6660680440182900
This research proposes the application of an artificial intelligence technique called genetic programming (GP) to make easier the programming of programmable logical devices (PLC) by the automatic generation of Ladder and Instruction List programs. The system data input can be done by not-specialized people using scenarios composed by time lines. These time lines demonstrate graphically the sequencing details of the PLC input and output permitting the programming of systems that uses memory like inter-locking contacts and the use of timers. Since GP is great dependent of its initial simulation parameters, thousand of simulations have been done to determine the better kind of configuration of cross-over and mutation
Projeto, implementação e automação de uma bancada para ensaios de motores de indução monofásicos
(Universidade Federal de Goiás, 2009-06-02) Viajante, Ghunter Paulo; Alvarenga, Bernardo Pinheiro de; http://lattes.cnpq.br/9850449311607643; Alvarenga, Bernardo Pinheiro de; http://lattes.cnpq.br/9850449311607643; Chabu, Ivan Eduardo; Nerys, José Wilson Lima; Marra, Enes Gonçalves
This work presents the project, construction and automation of a test bench for single-phase induction motor, up to 1 CV, based on a Brazilian Standard, ABNT 5383- 2/2007. In order to reach this purpose, theoretical studies on data acquisition systems, virtual instrumentation, industrial communication protocols and normalized testing methodologies are performed. After test bench construction, tests based on the Brazilian Standard are performed, in order to test a single-phase induction motor with starting capacitor .The tests results are presented.
Aplicação da Tecnology Readiness Index para definição de escopo em projetos de automação
(Universidade Federal de Goiás, 2009-06-27) CASTRO, Marcia Inocencio de; GUEDES, Leonardo Guerra Rezende; http://lattes.cnpq.br/9989795822168281
The study of behavior adoption products and services - based technology by the consumer is as a great helper choices for design projects and in targeting market, represented a challenge for new products and technological services therefore means intensive growth of these products, various studies indicate also the frustration of consumers interact with technology acquired. Such evidence are particularly important as consumer beliefs are positively related to your acceptance or resistance in adopt products and technological services. In this context, the readiness to technology emerges as construct fundamental to understanding attitudes on consumer technology. This work is the general objective to propose a method to help engineers electricians in the design project automation home (AR) based on user profile technology from the analysis of personal characteristics, rather evaluating the propensity of individuals with adopt products and technological services air from drivers and inhibitors mental related optimism, inovatividade, discomfort and insecurity. We use as method technology readiness index (TRIx). With this, this work is useful in engineering project air, leading to a design of a project as close as possible claim preference and characteristic of the user / customer is aimed at greater satisfaction and quality products and solutions offered by AR
PLANEJAMENTO DE REDE DE DISTRIBUIÇÃO DE ENERGIA ELÉTRICA COM RESTRIÇÕES GEOGRÁFICAS E ELÉTRICAS
(Universidade Federal de Goiás, 2009-06-29) RIBEIRO, Geraldo Valeriano; BRITO, Leonardo da Cunha; http://lattes.cnpq.br/6660680440182900; MACHADO, Paulo César Miranda; http://lattes.cnpq.br/8831309316416795
This work presents two methods to solve the problem of Electric Distribution Networks (EDN) with geographical and power restrictions. The high cost of the project involving EDN together with lack of efficient methods when working with real applications justifies the development of this research. Taking into account concepts of heuristic and metaheuristic two methods are proposed: The first is based on the Hill-Climbing (HC) heuristic and the second is based on the Simulated Annealing (SA) metaheuristic. The possible paths are provided by the Delaunay triangulation and it is considered the natural and socio-political obstacles of the site where you want to locate a new energy network. The dimension of the EDN feeders is calculated using the power flow results from the Forward-Backward method. The initial solution is found using an intelligent method. Then the SA metaheuristic and/or HC heuristic are used providing a good solution for a new EDN in comparison with the heuristic used to find the initial solution. A comparison is also made between the two proposed methods
PROJETO, IMPLEMENTAÇÃO E AUTOMAÇÃO DE UMA BANCADA PARA ENSAIOS DE MOTORES A RELUTÂNCIA CHAVEADOS
(Universidade Federal de Goiás, 2009-06-30) TEIXEIRA, Weldon Carlos Elias; ALVARENGA, Bernardo Pinheiro de; http://lattes.cnpq.br/9850449311607643
This work presents a proposal for testing Switched Reluctance Motors, which is feasible by the design and construction of an automated test bench. The test proposal intends to measure phase s resistance; to compute copper loss; to obtain the magnetizing curves for aligned and unaligned rotor and a performance test, which is based on fixing the under test motor rotor speed by a drive machine that is drove by a frequency inverter. The computational automation is restricted in changing the d.c. voltage applied to the under test switched reluctance motor by a programmable sinusoidal voltage source; changing and/or fixing the under test rotation speed of the switched reluctance; changing the semiconductor-switch switching angle; acquisition and processing of the data obtained in the tests. Computational simulations were performed for validating tests results made in an available switched reluctance motor
Mitigação de riscos em aeronaves: estudo da interface elétrica para UTI aerotransportada
(Universidade Federal de Goiás, 2009-08-14) Gusmão Sobrinho, Agnaldo de; Guedes, Leonardo Guerra de Rezende; http://lattes.cnpq.br/9989795822168281; Cruz Júnior, Gelson da; http://lattes.cnpq.br/4370555454162131; Cruz Júnior, Gélson da; Silva, Solange da; Guedes , Leonardo Guerra de Rezende
Aspect of electric fail in aircraft has been occupied space for discussion between scientific and the general communication because of the occurrence piece in the aeronautic sector. This work discusses a problem of Risk Analysis in aircraft, especially in the scope of the interconnection of the electric system to the medical air ambulance embedded equipment. The limitation aspect that the applicability of the Brazilian Aviation Regulations and Certification “Regulamento Brasileiro de Homologação Aeronáutica (RBHA)” has been analyze, whereupon the political conjunction with the general procedures established on the Manual Procedures Certification “Manual de Procedimentos de Homologação (MPH-500-04)”, which those requirements for the production certification is used for an emergency environment is showing as a mitigated factor of operational risk. The application of the regulation in this work restrict of the installation and operation of the electric interconnection between aircraft and the medical air ambulance equipment for the emergency air ambulance transportation. The instruction model plan to control the risk has contacted with the principles theory of risk and discuss the scope for application of the electric interconnection to make sure a secured supply of electric energy to the medical equipment and to applied a charge for respective battery , during the no generation of electrical feed to the aircraft.
Proposta de um sistema de gerência de redes PLC utilizando SNMPv3
(Universidade Federal de Goiás, 2009-08-20) OLIVEIRA, Diogo Nunes de; DEUS JÚNIOR, Getúlio Antero de; http://lattes.cnpq.br/8531659368461322; VIEIRA, Flávio Henrique Teles; http://lattes.cnpq.br/0920629723928382
ACCESS technologies for data transmission, such as xDSL, Wi-¯ and cable modem are widely used because they support high data transmission rates at low cost. Among these technologies, Power Line Communications, known as PLC, is a promising solution. PLC technology transmits data over power network, which presents high capilarity, due to the fact that it is present in 99% of residences. Since most of its structure already exists, power supply concessionaries started investing in this solution to stop being only a power supply concessionary and to be also a telecommunication company. In order to obtain control over a technology it is necessary to use management techniques that permits the maximum extraction of information from technology and involved devices. One of the goals of this work is to present the management solution developed to PLC networks. This solution di®ers from network management solutions used on other data transmission technologies due to the transmission media utilized. The management software used as base of the management system implemented is a free and no cost software. The concept of free code was adopted to the solutions implemented to the management system. The other goal of this work is to present the proposal and implementation of an embedded system based on PIC microcontroller that performs conversion of versions of SNMP protocol, which is the default management protcol in TCP/IP based networks. This converter device brings security to PLC networks management, since PLC devices only support version 2c of SNMP protocol, which is faulty regarding security. Since SNMPv3 supports authentication and privacy al gorithms, the designed converter device is capable of providing security, due to its capacity of coding a SNMPv2c packet into a SNMPv3 packet, and vice-versa.
A Utilização de Redes Neurais Artificiais na Estimação da Cobertura do Sinal de Televisão Digital
(Universidade Federal de Goiás, 2009-08-21) SILVA, Douglas Dias da; DEUS JÚNIOR, Getúlio Antero de; http://lattes.cnpq.br/8531659368461322
THIS works presents information about signal intensity obtained on field and from simulations for one-seg and full-seg receptions, the city of Goi ania. The values obtained from measurements were used for a comparisson among propagation models that are presented in literature, and the goal is to determine the real condition of digital TV signal in the region of Goi ania. The propagation models presented are available in literature and can be implemented in digital transmission system. The studied models were Free Space model, Log-Distance model, Hata model and ITU-R P.1546-1 method, and the objective was to determine the signal intensity of digital television transmission in the city of Goi ania (RAPPAPORT, 1996) (UNION, 2003). Focusing on the development of a tool for signal intensity estimation, some researches were done about neural networks theory and its applications. Perceptron and Multilayer Perceptron were the analised architectures, emphasyzing on the last one and on its supervisioned trainning through the backpropagation error algorithm (HAYKIN, 2001). The Brazilian Digital Television System was described by reference rules made by Associa¸c ao Brasileira de Normas T´ecnicas, which has detailed its transmission system and reception devices (T´ECNICAS, 2008a) (T´ECNICAS, 2008h). Measurements of signal intensity for one-seg and full-seg reception methods were made on field in the region of Goi ania. These measurements followed the sugestions presented by Report ITU-R BT. 2035-1 and it used a radiofrequency analyzer and a Global Positioning System (GPS). With the obtained data, the digital signal covering situation in the city of Goi ania was mapped, which revealed a lower intensity level to the studied models. A tool for signal intensity estimation was developed using Artificial Neural Networks, which was trained with the dada obtained from the performed measurements. This tool was used to obtain the signal intensity for several proposed scenarios. The signal intensity estimation for the scenario that has tree density and target absence distinguished as the one that was closest to the reality of Goi ania, which is a consequence of high density of trees.
Controle Inteligente de Tempo Livre em Tutoria Multissessão
(Universidade Federal de Goiás, 2009-08-22) GOMES, Viviane Margarida; NALINI, Lauro Eugênio Guimarães; http://lattes.cnpq.br/7555089672749145; MARTINS, Weber; http://lattes.cnpq.br/3123848470517021
Intelligent Tutoring Systems are softwares to provide customized instruction by using techniques of Computational Intelligence. This research proposes the intelligent control of free time (break interval) in multi-session tutoring. The teaching strategy employs tutoring modules with the following steps: 1) video class, 2) exercise, 3) practical suggestion, 4) free time, and 5) revision exercise. As part of the learning environment, free time (step 4) can contribute to increase the knowledge retention. Based on the student performance in exercises, the proposed system uses Reinforcement Learning to control free time durations. The intelligent agent decides according to the policy that has been indicated by the Softmax method. Among the relevant points of this algorithm, it can be highlighted the optimistic initial values, the incremental implementation and the temperature adjustment (Gibbs distribution parameter) to the selection of action. Two student groups have participated of data collection. The experimental group (with intelligent control) has been compared to the control group (where decisions belong to the student). In the groups, the intelligent agent or the student determines the action that will be followed or, in more detail, if free time will be shorter, longer or maintained. In comparison, statistical data analysis have shown significant and equivalent gains in knowledge retention. However, students from experimental group have realized more accurately the role of free time as a component of the teaching strategy
Estudo empírico de avaliação inteligente computadorizada de questões abertas baseado em colaboração
(Universidade Federal de Goiás, 2009-09-12) CORRÊA, Kleber Pullig; MACHADO, Paulo César Miranda; http://lattes.cnpq.br/8831309316416795
This research submits to experimental tests in real-world environment, the Conexionist Collaborative Intelligent Evaluation System idealized by Martins (2004) and tested with simulations by Guimarães (2004), who have noticed consistent and promising results when dealing with synthetic datas. The system explores the Learning Theory by Kolb (1984), Peer Collaboration Evaluation and Artificial Intelligence (multilayer perceptrons neural networks), which are capable to apply and correct tests with open (free) questions. To get a real-world data, some students from the course of Engineer registered at Universidade Federal de Goiás (UFG) on the period of june 2008 to july 2009 were taken in heterogeneous groups composed by men and women in age from 16 to 26 years old and at least 18 students per test. The software SAICOweb, developed specifically to this data collection, allows the computerized evaluations of open (free) questions, by using methods and stages described at Guimarães (2004) research. SAICOweb system were experimental validited in a satisfactory way by an unique group composed by 38 students (by using two tests with 08 open questions each). The analisys of the results with Pearson correlation shows strong association (0,81) between grades given by SAICOweb and the human grades (corrected by professors). Another important result is the satisfaction of professor and students when evaluating Software SAICOweb, evaluation method, pedagogical experience and anonymity. Specific itens were identified and suggested as future updates, when more experimental tests should be designed to validade other aspects of the System.

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