Engenharia Elétrica

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http://repositorio.ufes.br/handle/10/17617

Programa de Pós-Graduação em Engenharia Elétrica

Centro: CT
Telefone: (27) 4009 2663
URL do programa: https://engenhariaeletrica.ufes.br/pt-br/pos-graduacao/PPGEE

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Agora exibindo 1 - 20 de 509

Analise comparativa de algumas estruturas de filtros digitais de segunda ordem imunes a ciclos limite
(Universidade Federal do Espírito Santo, 1994-08-19) Simmer, Ana Cristina Staut; Orientador1; Sarcinelli Filho, Mário
This work is a comparative study of the relative output roundoff noise variance performance for some second-order state-space structures, as a function of the filter bandwidth. The addressed second-order structures are used as building blocks for realizing lowpass, highpass, bandpass and bandreject digital filters. In this sense, this study complements a recent one, which just investigated the lowpass filter case. In both studies only narrow-band digital filters are discussed, regarding the well known good performance of the state-space structures in those cases. In order to compare the output roundoff noise performance for all spectra, new firstorder spectral transformations, derived from the well known transformations due to Constantinides, are developed, for varying the filter bandwidth of a parallel-form prototype filter. All this effort is justified by the importance of knowing the performance of the structures which are suitable for a desired application, what represents a significative contribution to the problem of designing digital filters.
Uma interface gráfica de usuário para projeto e implementação de filtros digitais com processador dedicado
(Universidade Federal do Espírito Santo, 1996-06-19) Machado, Arnaldo Cordeiro; Schneebeli, Hans Jorg Andreas; Sarcinelli Filho, Mário; Coradine, Luis Claudius; Pequeno, Mauro Cavalcante
This work describes a software platform developed in order to support the design and DSP-based implementation of digital filters. It is a WINDOWS program designed to run on a personal computer containing a DSP board. A card based on the 16-bit fixed point Texas Instruments TMS320C25 chip is used, which is attached to the ISA PC bus. The developed software is specially designed to accomplish three main features: the filter design task, restricted to the PC microprocessor, the real-time synchronous filter algorithm, running exclusively on the DSP, and the necessary information exchanging between both processors, and between the PC computer and the user, in order either to load filter parameters or to check for the filter input/output signals. In addition, the user may edit/view text files containing the filter transfer function or network coefficients, or edit/compile/debug files that contain assembly code for the DSP.
Sobre o projeto de filtros digitais de segunda ordem imunes a ciclos limite
(Universidade Federal do Espírito Santo, 1998-12-30) Camponêz, Marcelo Oliveira; Sarcinelli Filho, Mário; Calmon, Luiz de Calazans; Mota, Francisco das Chagas
A set of three constant-input limit cycle-free state-space second-order digital filtersections were proposed in a paper of 1986, to be used as building blocks for cascade orparallel higher order filter design. They were called structure type I, structure type II (which isentirely identical to the first one) and structure type III, by the authors who proposed them.Those structures are different from other constant-input limit cycle-free second-orderbuilding blocks in the sense that they are computationally less complex. As showed in thepaper that introduced it, the structure type I is also a low roundoff noise one, when comparedto the minimum noise structure designed under L∞ scaling. Unfortunately, because thestructure type III is slightly more complex than the structure type I (its demands three two-input adders more to be computed), its synthesis procedure and noise performance were notaddressed in the initial paper. However, it was demonstrated later, that the structure type IIIpresents relative output roundoff noise variances lower than the structure type I for the case ofL2 scaled lowpass filters.Then, in this work, the structure type III is revised, and new strategies for designing itare proposed. Under proper design, it is showed that the relative output roundoff noisevariance is minimal. Both L2 and L∞ scaling are here discussed. Examples are shown tosupport the results presented.Finally, in order to stress the good noise performance of the structure type III designedaccording to the strategies here discussed, it is compared to the noise performance of someother filter structures known in the literature. The conclusion is that the new structure type IIIhere proposed is a good candidate for being the building block to implement high ordernarrowband filters.
Sistema de visão para robôs móveis: uma aplicação ao reconhecimento de referências geométricas
(Universidade Federal do Espírito Santo, 1999-02-26) Freitas, Roger Alex de Castro; Sarcinelli Filho, Mário; Bastos Filho, Teodiano Freire; Almeida, Ailson Rosetti de; Rillo, Márcio
The availability of sensorial data is an important issue for the navigation systemof autonomous mobile robots. The robot needs information about its surroundingenvironment in order to make a decision on what to do when it faces an obstacle. Insome cases, it not only does need to detect the presence of the obstacle but also torecognize it. This way, it is necessary that the onboard sensing system be much morespecialized. For an agent-based controlled autonomous mobile robot, a sensing systemthat combines ultrasonic sensors and artificial vision is here addressed. It makesavailable information about the type of obstacle detected in the trajectory of the robot, aswell as the distance from the detected object to the robot. This external sensing systemis also able to avoid the generation of redundant and unnecessary information, besidesnot demanding too much computational effort to process the acquired images onboardthe robot
Controle de robôs móveis por fusão de sinais de controle usando filtro de informação descentralizado
(Universidade Federal do Espírito Santo, 2002-08-14) Freire, Eduardo Oliveira; Bastos Filho,Teodiano Freire; Sarcinelli Filho, Mário; Carelli, Ricardo; Schneebeli, Hansjörg Andreas; Nasisi, Oscar; Salles, José Leandro Felix; Bergerman, Marcel
This thesis proposes an alternative approach to deal with the problem of mobile robot navigation, which is called fusion of control signals. The proposed technique has presented good results when a robot has to execute relatively complex tasks, like it is shown in the experiments here presented. The technique is developed with basis on the decentralised information filter, whose equations are here derived from the equations of the decentralised Kalman filter and the information filter. Motion controllers available in the literature and others introduced here for the first time are used to produce the control signals that are fused using a decentralised information filter in order to produce the overall output signal to be sent to the actuators. A stability analysis of the proposed architecture is also addressed.
Navegação reativa de robôs móveis com base no fluxo óptico
(Universidade Federal do Espírito Santo, 2002-12-11) Caldeira, Eliete Maria de Oliveira; Schneebeli, Hans Jorg Andreas; Sarcinelli Filho, Mário; Campos, Mário Fernando Montenegro; Rillo, Márcio; Bastos Filho, Teodiano Freire; Salles, Evandro Ottoni Teatini
This Ph. D. Thesis proposes to perform the navigation of mobile robots using a sensing system completely based on the optical flow which is calculated from a sequence of two images acquired by a camera fixed onboard the robot. To check the feasibility of using the proposed sensing system, a control system is designed to give the robot the capability of reacting to environmental changes, while executing the wander behavior with obstacle avoidance. The control system uses only data coming from the visual sensing system based on the optical flow. No modification is required to the robot’s environment, such as adding suitable textures or adjusting illumination. The optical flow is calculated considering that images are acquired when the robot is moving ahead with a null angular velocity. Then, a segmentation algorithm based on the optical flow field is proposed and implemented to detect distinct objects present in the scene. The distance from the robot to each object is then estimated based on the time to impact calculated from the optical flow field. The control system uses the time to impact corresponding to each object to determine a new direction to be followed by the robot. It then sends to the robot actuators the suitable commands to change the robot’s orientation. Both the sensing and control systems are implemented onboard a Pioneer 2-DX mobile robot and are used in a set of experiments, and the results show that the navigation system implemented presents very good performance.
Inspeção visual automática de mamões
(Universidade Federal do Espírito Santo, 2003-12-17) Simão, Josemar; Orientador1; Schneebeli, Hans Jorg Andreas; Koo, Robert Liang; Loureiro, Getúlio Vargas; Salles, Evandro Ottoni Teatini
This work shows the development of an automatic inspection system for papaya fruits. This system can measure the size and the degree of maturation of the fruits, and classify them accordingly. The regional sector of papaya production and exportation has grown and the use of an automatic visual inspection system can contribute for the production increase and maintenance of the standards of quality demanded by the consuming markets. The automatic visual inspection systems have often been an alternative to the traditional processes of inspection done by trained individuals. The main reasons are costs reduction and the guarantee of the quality standard assured by the inspection of all fruits in a lot. In contrast, human inspectors get tired with repetitive work and present inconsistency in the inspection criteria. The system basic structure is a conveyor belt carrying a continuous flow of fruits and a digital video camera, located above, which gets a sequence of images of the moving fruits. These images are processed and analyzed by a personal computer. The first processing stage is the conversion of color to binary images for fruits dimensions estimation. The maturation is quantified by a hue histogram curve of the fruits in the color images. Comparing with data in a database, that stores the knowledge of experts, the information acquired can be used to classify the fruits and set up a mechanism capable to separates them as necessary. The results had shown that a set of the simple hardware could evaluate the dimensions and the degree of maturation of the fruits despite illumination changes.
Desvio tangencial de obstáculos para um robô móvel navegando em ambientes semi-estruturados
(Universidade Federal do Espírito Santo, 2004-06-28) Ferreira, André; Bastos Filho, Teodiano Freire; Sarcinelli Filho, Mário; Freire, Eduardo Oliveira; Caldeira, Eliete Maria de Oliveira
This thesis proposes a new strategy for a mobile robot to deviate from obstacles while navigating in a semi-structured environment. The proposed control architecture is based on a reactive approach, thus demanding low computational e®ort. It allows the robot to navigate from a starting point to a destination point without colliding to any obstacle in its path. The deviation from an obstacle is performed according to an escape angle calculated so that the new robot orientation is tangent to the obstacle. It is also shown that such strategy generates more e±cient trajectories, in the sense that the destination point is reached in less time while saving energy and reducing the demand on the robot motors. Another interesting aspect of the proposed strategy is that it also allows to implement the behaviors Wall Following and Corridor Following. The proposed methodology is validated through simulated examples and practical experiments as well, which were run in a PIONEER 2-DX mobile robot.
Controle da navegação de um robô móvel em um corredor com redundância de controladores
(Universidade Federal do Espírito Santo, 2004-06-29) Gamarra, Daniel Fernando Tello; Bastos Filho, Teodiano Freire; Sarcinelli Filho, Mário; Freire, Eduardo Oliveira; Caldeira, Eliete Maria de Oliveira
abstract
Comparação das técnicas de modulação multiportadoras aplicadas às comunicações via rede elétrica
(Universidade Federal do Espírito Santo, 2004-07-09) Dezan, Tadeu Leite; Segatto, Marcelo Eduardo Vieira; Salles, Evandro Ottoni Teatini; Almeida, Ailson Rosetti de; Lima, Antônio César de Castro
The use of the low voltage energy grid as high speed communication networks, known as Power Line Communication – PLC, opens up the possibility to establish low cost widespread local area networks services such as internet. In this master thesis dissertation, transmission issues on the power line are investigated and modeling aproaches are investigated. Multi-carrier modulation based on orthogonal transmultiplexer is used, because of its fast algoritms capabilities. Three diferent techniques are compared: Orthogonal Frequency Division Multiplexing, Discrete Wavelet Multitone through Extended Lapped Transform and Wavelet Packet Modulation. The main characteristics of each technique, including their computational cost, are described based on the filter banks theory. The system performance is analysed in terms of the bit-error rate versus signal-tonoise rate in a multipath powerline channel.
Estratégias para deslocamento de cargas através de cooperação entre robôs móveis a rodas
(Universidade Federal do Espírito Santo, 2004-12-22) Bragança, Jaines de Oliveira; Sarcinelli Filho, Mário; Bastos Filho, Teodiano Freire; Salles, Evandro Ottoni Teatini; Ferasoli Filho, Humberto
This work deals with the control of cooperative robots, using a non linear position controller. The feedback of the control loop is carried out using a camera located over the environment where the robots actuate. After capturing an image, it is processed into a computer, which is responsible for generate the set point to the robots. It was used only a non linear position control and it was possible develop strategies for allowing the displacement of an object using two robots to push it. These strategies consist of analyzing the position and orientation of the object in order to displace it. In addition to these strategies, several tasks were developed by the robots, allowing them reaching a destination point or follow a predefined path. Also, tasks to the robots like formation in a line or side to side were implemented in this work.
Análise de sistemas de multiplexação por subportadora - SCM
(Universidade Federal do Espírito Santo, 2005-03-22) Togneri, Arnaldo Paterline; Orientador1; Segatto, Marcelo Eduardo Vieira; Ribeiro, Moisés Renato Nunes; Pohl, Alexandre de Almeida Prado
abstract
Interpretação automatizada de textos : processamento de anáforas
(Universidade Federal do Espírito Santo, 2005-04-11) Freitas, Sérgio Antônio Andrade de; Lopes, José Gabriel Pereira; Menezes, Crediné Silva de; Cury, Davidson; Garcia, Berilhes Borges; Vicari, Rosa Maria; Tavares, Orivaldo de Lira
This thesis presents a solution to the interpretation of de nite descriptions in Portuguese. For example, consider the following text: (1) a. Mariana bought a new car. b. The engine was damaged. The sentence (1a) introduces two entities: Mariana and a car which is new. The sentence (1b) introduces only one entity the engine. In a human or computer interpretation process, the use of the de nite article the preceeding a noun indicates that the introduced entity was already present at the discourse, i.e., it is an anaphoric entity. The resolution of an anaphora is a reference problem, but in the example (1) there is another problem: although the car is the entity that gives context to the engine, we can not say that the engine is the car (as for a pronominal anaphora). It also must be determined how the engine is related to the car. This is a de nite description problem. The interpretation of any kind of anaphora can be represented by the following equation: R(A, T ) (2) where A denotes an entity introduced by the context interpretation of a pronoun, an ellipsis or a de nite noun phrase, T denotes its antecedent and R is the relation between A and T . The equation's resolution process is summarized as: given A nd T and R. This thesis proposes a methodology to the de nite description interpretation that the relation R is of: part of, member of, subcategorized by and corefers. These relations are obtained by a set of pragmatic rules [Freitas, Lopes e Menezes 2004, Filho e Freitas 2003], which are here de ned (chapter 3). Also if A is not anaphoric then it is acommodated in the discourse context. The computational methodology is implemented in a logic programming system [Damásio, Nejdl e Pereira 1994] that permits an abductive reasoning [Kakas, Kowalski e Toni 1992] at the semantic representation of the discourse [Kamp e Reyle 1993]. The interpretation of the entities is the basis to the Discourse Nominal Structure [Lopes e Freitas 1994] (chapter 4), which allows: (1) to track the most salient entities at each sentence [Freitas e Lopes 1994], (2) to limit the number of possible antecedents [Freitas e Lopes 1996] and (3) to give a discourse entities summary. The result is an integrated metodology to solve anaphors and ellipses. Finally, the Nominal Structure of the Discourse can help the search/index of digital documents.
Análise da aplicação de conexão em paralelo de capacitores em circuitos secundários de baixa tensão
(Universidade Federal do Espírito Santo, 2005-05-13) Sarcinelli, Carlos Alberto; Sousa, Gilberto Costa Drumond; Simonetti, Domingos Sávio Lyrio; Aragão Filho, Wilson Correia Pinto de; Pomílio, José Antenor
The objective of this work is to analyze the behavior of a radial low voltage secondary distribution network subject to linear and non-linear loads, with and without magnitude voltage control by the automatic insertion of capacitor banks. The analysis is performed by considering the variations in the secondary distribution network elements. These elements are the loads connected to each pole of the network (power varying from no-load to full load, and displacement factor varying from 0.7 to 1.0), the changes in the ratings of the supply transformers (apparent power in kVA, primary and secondary impedances, and primary and secondary voltages), the number of poles and the distance among them. The harmonic behavior of the rms voltage of the distribution network is also analyzed, with and without the insertion of a capacitor bank at the last pole, since the distribution network might amplify harmonics as a result of resonances in the system, which have influence on the control of the voltage magnitude. Finally, a steady-state frequency domain analysis is performed by using a computer program (MATLAB), whose results are confirmed through time domain simulations performed using SIMULINK. The results concerning the time and frequency analyses are presented as a set of plots, from which some conclusions are highlighted, for a case study consisting in a network having five poles and a 13,800/220 V, 75kVA transformer.
Sintonia do ganho de escorregamento de um servoacionamento por controle vetorial de um motor de indução trifásico
(Universidade Federal do Espírito Santo, 2005-05-25) Massaro, Claudio Menegatti; Sousa, Gilberto Costa Drumond; Fardin, Jussara Farias; Rey, Joost Pieter
Servo drive applications require fast dynamic responses. Modern power electronics and Microcomputers enabled high performance ac drives for this purpose and the induction motor cage type is the most commonly used in adjustable-speed ac drive systems because of its robustness and low-cost. Vector control of an induction motor surpasses the performance of a direct current motor but the control method is inherently complex. The indirect vector control method, used in the present work, has a problem of performance degradation due to parameter variations, mainly rotor time constant, which is used in the slip gain calculation. An adaptive observer of an induction motor with a parameter adaptive scheme is proposed for tuning the slip gain calculation, in the present work. The system simulations were performed using Matlab/Simulink software to demonstrate its effectiveness. An experimental study with assembly software implementation was carried out, by using of a Texas Instruments DSP board.
Uso de acoplamento magnético na melhoria de características de algumas estruturas ZVT
(Universidade Federal do Espírito Santo, 2005-06-10) Menegáz, Paulo José Mello; Vieira, José Luiz de Freitas; Simonetti, Domingos Sávio Lyrio; Hey, Hélio Leães; Souza, Gilberto Costa Drumond; Có, Marcio Almeida; Aragão Filho, Wilson Correia Pinto de
This Dissertation presents two families of non-isolated DC-DC ZVT-PWM converters which employ a magnetic coupling to implement the topological auxiliary voltage source. The first proposed family of converters belongs to the group of ZVT converters with switched auxiliary voltage source. It makes use of a magnetic coupled regenerative snubber applied to the auxiliary switch of the ZVT converter in order to assure a zero voltage transition commutation during its turn-off. The auxiliary switch turn-on occurs at zero current and the main switch presents both the turn-on and the turn-off at zero voltage, as in the conventional ZVT topology. The magnetic coupling is responsible to produce the necessary conditions for the resonant discharge of the snubber capacitor, transferring the energy stored in the capacitance to the converter input and/or output. A more compact topology is achieved by using the leakage inductance of the magnetic coupling as the resonant inductance itself, which reduces the number of magnetic components of the converter. The second proposition belongs to the group of ZVT converters with DC auxiliary voltage source. In this family of converters, a magnetic coupling between the main and the resonant inductors is used in order to guarantee that the auxiliary switch will work at its minimum total loss point. The main and the auxiliary switch commutation remains unchanged if compared to the commutations of the converter without magnetic coupling. Once both the main and the resonant inductors of the converter are built in the same magnetic core, the number of magnetic components is reduced, as well as the number of EMI sources. For both propositions, equations describing the voltage and current behavior of the main elements of the converter are given. Beside this, a design procedure that allows a quick and simple choice of the magnetic coupled cell elements is also presented. At the end of this work, simulation and experimental results obtained by the construction of the proposed converter prototypes are shown. They validate the equations and design procedures developed in the work and demonstrate the improvement achieved by using the proposed enhancement.
Análise de dispersão em fibras PCF com o método de elementos finitos
(Universidade Federal do Espírito Santo, 2005-06-29) Ramos, Breno Guimarães; Frasson, Antonio Manoel Ferreira; Calmon, Luiz de Calazans; Figueroa, Hugo Enrique Hernandez
In the present work, the full vectorial, total anisotropic, Finite Element Method was implemented, using second order nodal base functions for the electric field longitudinal component discretization, and Nedelec base functions, quadratic normal and linear tangencial (QNLT), for the discretization of the magnetic field transversal component, applying triangular elements in the domain of solution. Through this implementation, it was studied several configurations of Photonic Cristal Fibers (PCF), making changes in the diameter of the holes and in the distance between then, also called pitch. The intention was to show how feasible and practical is the control of the ultraflattened dispersion profile for this new model of optical fiber, as was reported in recent works. The calculated dispersion results shown that is possible to get dispersion profile completely flat in a range of wavelength of 200 nm, and with the possibility to add offsets in this profiles, making it negative (for applications related to dispersion compensation), or yet, making it flat in a region as close as possible to zero, what is very useful for WDM multiplexing systems. In addition to the dispersion evaluation, the method developed also allows to calculate the effective modal area and also features a graphical presentation of the electric field distribution, or the magnetic field distribution, of the guided modes in the fiber. Concerning the tailoring of the dispersion curve, applying finite element simulation, it was validated the use of empiric equations for dispersion computations from scaling operations in the structure of PCF fibers. These equations can simplify even more the procedure of dispersion tailoring, because the number o simulations by finite element method is reduced considerably. It was also important to analyze the behavior of the propagating wave in the fiber’s interior. For this, it was implemented the Beam Propagation Method (BPM) using two different approaches. Initially, it was applied Crank-Nicholson method, which didn’t show good results because it was not possible to stabilize the propagation process. As a second option, the Newmark method was used, but it was only possible to make the propagation process stable with a simulation step which had the same order of magnitude of the wavelength applied. Thus, unfortunately it was not possible to observe any phenomena of interest during the guiding process.
Modelo termomicroestrutural para determinação de variáveis operacionais e metalúrgicas para utilização em simulação e/ou controle na laminação a quente de aços carbono e microligados
(Universidade Federal do Espírito Santo, 2005-07-15) Machado, Marcelo Lucas Pereira; Denti Filho, José; Ferreira, Edson de Paula; Salles, José Leandro Félix; Arantes, Denio Rebello; Caccioppoli, José Maria Ramon
Due to the strong relationship between the microstructural changes and the mechanical properties of steel in a hot strip mill, the development of models that take into consideration metallurgic steel properties and operational variables with the objective of optimizing the process has become more necessary. The developed thermomicrostructural model calculates the mean flow stress taking into account accumulated strain between passes to incorporate the effect of the static, dynamic and metadynamic recrystallization. This thermomicrostructural model also allows the calculation of the austenite grain size between passes and the ferrite grain size after the steel leaves of the last stand. The model calculates the roll force in all the stands taking into consideration the effect of the strip tension between stands applied on the material during rolling mill and the work roll gap. Therefore, the material exit thickness for each stand or the material entrance thickness of the next stand can be calculated. A thermal model was developed, where the usual thermal equations were used to calculate the thermal exchanges of the steel in the hot strip mill. With this, the thermomicrostructural model can calculate the thermal, microstructural variations, mean flow stress that occurs in the steel and also the roll force, exit thickness and entry temperatures of the steel in each stand, in the hot strip mill. The model also closely agreed with the industrial data of different hot strip mills and for different types of carbon and microalloyed steels and for literature data. Then operational disturbances in the thermomicrostructural model were introduced and sensitivity curves were plotted that showed the changes that these disturbances cause in the steel properties, such as, mean flow stress, grain size, strip temperature, material exit thickness and roll force, not only in the one specific stand but also the effect in the next stands. Using the simulations, it was elaborated a group of qualitative rules that make it possible to determine which actions should be taken if the disturbances occur in the material thickness and/or entry temperature and/or mean flow stress and the corrections to be done in the manipulated variables, which are the roll gap, the strip tension between stand and the work roll speed, aiming to recover the strip thickness, improve mechanical properties and reduce roll force. It can therefore determine the priorities and measures that are needed for the mechanical properties of the material, microstructure and steel exit thickness and also the roll force as an operational parameter. These qualitative rules provide a base to develop some type of programming aimed at hot strip mill control, such as a soft computing program.
Projeto de Topologias Virtuais para Redes Opticas Multiserviço
(Universidade Federal do Espírito Santo, 2005-08-05) Almeida, Renato Tannure Rotta de; Calmon, Luiz de Calazans; 1º membro da banca
Optical communication systems have emerged as the best solution for large scale data transport network implementation, providing optical channels with very high bit rates and covering large distances with low error probability. The entire bandwidth of the optical fibers became available with the development of the wavelength division multiplexing (WDM) technology, which allows several channels of different wavelengths to share the same physical links. The increase in physical link capacity was not the only benefit of WDM. The development of WDM optical devices, e.g., optical switches, multiplexers, demultiplexers, and tunable devices, has allowed the implementation of wavelength-routed optical networks. In such networks, the optical channels, also called lightpaths, are not restricted to the physical link edges. Wavelength routing detaches the lightpath configuration, or virtual topology, from the physical topology, permitting lightpaths to optically bypass intermediate nodes, until it reaches the destination node. In this Thesis we propose a Mixed-Integer Linear Programming (MILP) formulation to design virtual topologies in wavelength-routed optical networks, considering as objective function the minimization of the traffic forwarded electronically at the network nodes. Our goal is twofold. Firstly, to reduce processing requirements of the electronic routers, and secondly, to get the most transparent traffic distribution for a given traffic matrix, using the available optical resources at the nodes. Traffic segregation in classes was also included in the formulation, allowing differentiated routing criteria to each class. The proposed formulation was applied successfully to reasonable sized networks yielding optimal solutions in few minutes. To the best knowledge of the authors, this is the first report of a large MILP formulation that optimizes virtual topology and traffic routing of optical networks with low computational cost.
Estudo do sinal eletroencefalográfico (EEG) aplicado a interfaces cérebro computador com uma abordagem de reconhecimento de padrões
(Universidade Federal do Espírito Santo, 2005-09-06) Azevedo, Anderson Prado; Almeida, Ailson Rosetti de; Salles, Evandro Ottoni Teatini; Bastos Filho, Teodiano Freire; Andreão, Rodrigo Varejão
The conjunction of signal processing, pattern recognition and brain electrical signal acquisition made possible a new communication modality, until now a subject for science fiction movies: the Brain-Computer Interface (BCI). This complex system can acquire and process the brain signals in order to obtain information to be used as a control signal. This innovation can benefit people who have neuromuscular disorders, which cause damages on the volunteer movement. These people would communicate, or even move, using a BCI to control electronic devices. Looking ahead, these systems can be used in other applications, mainly for multimedia purposes. The purpose of this work is study the EEG characteristics, the signal processing and pattern recognition techniques in order to use in a Brain Computer Interface (BCI) For this, will be used a international data base, in order to compare our results with results of other international groups. In this context, this work describes the human brain and the EEG characteristics relevant to BCI understanding. Moreover, it presents the implementation of a pattern recognition system, which is able to classify the motor imagination laterality with accuracy over 85%.

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