sinopseV2n1

Transcrição

sinopseV2n1

SINOPSE DA FEEC
Volume 2 - Issue 1
January -April 2009
FEEC-UNICAMP Academic Bulletin
minimizar a soma dos atrasos. O método utiliza Busca Tabu como
estratégia de exploração do espaço de soluções. Duas vizinhanças
são utilizadas: Troca e Inserção. Avalia-se o efeito de diferentes
soluções iniciais, dentre estas, adaptações de regras de despacho e
do algoritmo NEH. Testes computacionais são apresentados, e
realiza-se uma comparação com o algoritmo NEH.
Editorial
This is the first issue of the second volume of “SINOPSE DA
FEEC” – the Academic Bulletin of the School of Electrical and
Computer Engineering (FEEC) of the University of Campinas
(Unicamp). In this issue we present the main academic results of
our Faculty work in the first four-months period of 2009. Among all
results we present here the abstracts of forty-three articles in
journals, forty-two articles in event proceedings, eight book
chapters, and two patent registrations. We also emphasize the
edition of a book, and the organization of three scientific events.
Two final sections present the abstracts of twenty-eight master
dissertations and eight doctoral theses defended in this period.
José Raimundo de Oliveira
FEEC Associate Director
Dynamic Output Feedback Control Of DiscreteTime Markov Jump Linear Systems Through Linear
Matrix Inequalities
Jose Cláudio Geromel, Alim P. C. Goncalves, Andre R. Fioravanti
SIAM Journal on Control and Optimization - ISSN: 0363-0129
v:48 n:2 Feb-2009 pp:573-593 doi: 10.1137/080715494
Abstract: This paper addresses the H2 and H∞ dynamic output
feedback control design problems of discrete-time Markov jump
linear systems. Under the mode-dependent assumption, which
means that the Markov parameters are available for feedback, the
main contribution is the complete characterization of all full order
proper Markov jump linear controllers such that the H2 or H∞ norm
of the closed loop system remains bounded by a given prespecified
level, yielding the global solution to the corresponding modedependent optimal control design problem, expressed in terms of
pure linear matrix inequalities. Some academic examples are
solved for illustration and comparison. As a more consequent
practical application, the networked control of a vehicle platoon
using measurement signals transmitted in a Markov channel, as
initially proposed in [P. Seiler and R. Sengupta, IEEE Trans.
Automat. Control, 50 (2005), pp. 356–364], is considered.
Keywords: linear systems, discrete-time systems, stochastic
systems, Markov jump linear systems, linear matrix inequalities
Articles in journal
Automation
BAIS: A Bayesian Artificial Immune System for the
Effective Handling of Building Blocks
Pablo Alberto Dalbem de Castro, Fernando José Von Zuben
Information Sciences - ISSN: 0020-0255
v:179 n:10 Apr-2009 pp:1426-1440 doi:
doi:10.1016/j.ins.2008.11.040
Abstract: Significant progress has been made in theory and
design of Artificial Immune Systems (AISs) for solving hard
problems accurately. However, an aspect not yet widely addressed
by the research reported in the literature is the lack of ability of the
AISs to deal effectively with building blocks (partial high-quality
solutions coded in the antibody). The available AISs present
mechanisms for evolving the population that do not take into
account the relationship among the variables of the problem,
potentially causing the disruption of high-quality partial solutions.
This paper proposes a novel AIS with abilities to identify and
properly manipulate building blocks in optimization problems.
Instead of using cloning and mutation to generate new individuals,
our algorithm builds a probabilistic model representing the joint
probability distribution of the promising solutions and,
subsequently, uses this model for sampling new solutions. The
probabilistic model used is a Bayesian network due to its
capability of properly capturing the most relevant interactions
among the variables. Therefore, our algorithm, called Bayesian
Artificial Immune System (BAIS), represents a significant attempt
to improve the performance of immune-inspired algorithms when
dealing with building blocks, and hence to solve efficiently hard
optimization problems with complex interactions among the
variables. The performance of BAIS compares favorably with that
produced by contenders such as state-of-the-art Estimation of
Distribution Algorithms.
Keywords: Artificial Immune System; Bayesian networks;
Building blocks; Combinatorial optimization
Information Retrieval with FROM: The Fuzzy
Relational Ontological Model
Rachel Pereira, Ivan Luiz Marques Ricarte, Fernando Antonio
Campos Gomide
International Journal of Intelligent Systems - ISSN: 0884-8173
v:24 n:3 Mar-2009 pp:340-356 doi: 10.1002/int.20339
Abstract: This paper presents FROM, the fuzzy relational
ontological model, a novel approach to encode knowledge for
information retrieval applications based upon a fuzzy set
framework that consider more generic concepts differently from
specific terms. Besides the model itself, the paper also presents a
retrieval algorithm that exploits FROM features through the
application of fuzzy operations that uses this knowledge to extend
a user's query based on these fuzzy associations. Experimental
results have shown that retrieval with FROM presented better
overall performance than other fuzzy-based approaches for
information retrieval.
Keywords: Fuzzy information retrieval,
fuzzy relational
modeling, fuzzy ontology
Robust absolute stability and nonlinear state
feedback stabilization based on polynomial Lur’e
functions
Busca tabu para a minimização do tempo total de
atraso no problema de flowshop
Vinícius Foletto Montagner, Ricardo Coração de Leão F. de
Oliveira, Taís Calliero Tognetti, Renato Alves Borges, Pedro Luis
Dias Peres, Christophe Prieur
Nonlinear Analysis: Theory, Methods & Applications - ISSN:
0362-546X
v:70 n:5 Mar-2009 pp:1803-1812 doi:
Débora Pretti Ronconi, Vinicius Amaral Armentano
Pesquisa operacional para o desenvolvimento - ISSN: 1984-3534
v:2 n:1 Jan-2009
Resumo: Este trabalho propõe uma heurística para o problema de
programação de tarefas no ambiente fl owshop com o objetivo de
doi:10.1016/j.na.2008.02.081
1
Abstract: This paper provides finite-dimensional convex
conditions to construct homogeneous polynomially parameterdependent Lur’e functions which ensure the stability of nonlinear
systems with state-dependent nonlinearities lying in general
sectors and which are affected by uncertain parameters belonging
to the unit simplex. The proposed conditions are written as linear
matrix inequalities parametrized in terms of the degree g of the
parameter-dependent solution and in terms of the relaxation level d
of the inequality constraints, based on the algebraic properties of
positive matrix polynomials with parameters in the unit simplex.
As g and d increase, progressively less conservative solutions are
obtained. The results in the paper include as special cases existing
conditions for robust stability and for absolute stability analysis. A
convex solution suitable for the design of robust nonlinear state
feedback stabilizing controllers is also provided. Numerical
examples illustrate the efficiency of the proposed conditions.
Keywords: Robust stability; Homogeneous polynomially
parameter-dependent Lur’e functions; Absolute stability; Linear
matrix inequalities
Robust stability H-2 analysis and stabilization of
discrete-time Markov jump linear systems wity
uncertain probability matrix
Ricardo Coração de Leão F. de Oliveira, Alessandro do
Nascimento Vargas, João Bosco Ribeiro do Val, Pedro Luis Dias
Peres
International Journal of Control - ISSN: 1366-5820 (electronic)
0020-7179
v:82 n:3 Mar-2009 pp:470-481 doi: 10.1080/00207170802136178
Abstract: The stability and the problem of H2 guaranteed cost
computation for discrete-time Markov jump linear systems (MJLS)
are investigated, assuming that the transition probability matrix is
not precisely known. It is generally difficult to estimate the exact
transition matrix of the underlying Markov chain and the setting
has a special interest for applications of MJLS. The exact matrix is
assumed to belong to a polytopic domain made up by known
probability matrices, and a sequence of linear matrix inequalities
(LMIs) is proposed to verify the stability and to solve the H2
guaranteed cost with increasing precision. These LMI problems
are connected to homogeneous polynomially parameter-dependent
Lyapunov matrix of increasing degree g. The mean square stability
(MSS) can be established by the method since the conditions that
are sufficient, eventually turns out to also be necessary, provided
that the degree g is large enough. The H2 guaranteed cost under
MSS is also studied here, and an extension to cope with the
problem of control design is also introduced. These conditions are
only sufficient, but as the degree g increases, the conservativeness
of the H2 guaranteed costs is reduced. Both mode-dependent and
mode-independent control laws are addressed, and numerical
examples illustrate the results.
Keywords: discrete-time Markov jump linear systems; uncertain
probability matrix; robust stability; H2 norm; state feedback
control; LMI relaxations
The game to play: expanding the co-opetition
proposal through the strategic games matrix
Eliezer Arantes da Costa, Celso Pascoli Bottura, João Mauricio
Gama Boaventura, Adalberto Américo Fischmann
International Journal of Conflict Management - ISSN: 1044-4068
v:20 n:2 Jan-2009 pp:132-157
Abstract: Purpose- Using Brandenburger and Nalebuff's 1995
co-optiton model as a reference, the purpose of this paper is to
seek develop a tool that, based tenets of classical game theory,
would enable scholars and managers to identify which games may
played in response to the different conflict of interest situations
faced by campanies in their business environments.
Design/methodology/approach - The literature on games matrix
(SGM), is devoloped Two novel games are described and
modeled. Findings - The co-opetition model is not sufficient to
realiscally represent most of the conflict of interest situations faced
2
by companies. It seeks to address this problem through
development of the SGM, which expands upon Brandenburger and
Nalebuff's model by providing a broader perspective, through
incorporation of an additional dimension (power ratio between
players) and three novel, respectively, (rival, individualistic, and
associative).
Practical implications - This proposed model, basead on the
concepts of game theory, should be used to train decision- and
policy-makers to better understant, interpret and conflict
management strategies.
Origiality/value - A practical and original tool to use game models
in conflict of interest situations is generated. Basic classical games,
such as Nash, Stackelberg, Pareto, and Minimax, are mapped on
the SGM to suggest in which situtions they could be useful. Two
innovative games are described to fit four different types of
conflict situations that so far have no corresponding game in the
literature. A test application of the SGM to a classic Intel
Corporation strategic management case, in the complex personal
computer industry, shows that the proposed method is able to
describe, to interpret, to analyze, and to prescrible optimal
competitive and/or cooperative strategies for each conflict of
interest situation.
Keywords: Game theory, Conflict, Management strategy,
computers.
Electronic, Opto-electronic, Micro-electronic
Performance investigation of microphotonic-silicon
devices in a field-trial all-optical network
J. D. Marconia, Arismar Cerqueira Sodre Jr., J.T. Robinson, N.
Sherwood-Droz, Y. Okawachi, Hugo Enrique Hernandez Figueroa,
M. Lipson, A.L. Gaeta, H. L. Fragnito
Optics Communications - ISSN: 0030-4018
v:282 n:5 Mar-2009 pp:849-855 doi:
doi:10.1016/j.optcom.2008.11.018
Abstract: The performance of microphotonic-silicon devices in a
geographically-distributed optical fiber network is experimentally
investigated. Two different devices are tested: an optical filter
based on a silicon ring resonator and an all-optical wavelength
converter based on four-wave mixing in a dispersion-tailored
highly nonlinear silicon waveguide. The evaluation of the devices
is performed by means of eye diagrams and measurements of the
bit error rate.
Keywords: Silicon ring resonators; Silicon waveguides;
Integrated optics; All-optical networks; Field-trial tests
Biomedical Engineering
A Novel Intraurethral Device Diagnostic Index to
Classify Bladder Outlet Obstruction in Men with
Lower Urinary Tract Symptoms
Leonardo O. Reis, Guilherme C. Barreiro, Alessandro Prudente,
Cleide M. Silva, José Wilson Magalhães Bassani, Carlos Arturo
Levi D'Ancona
Advances in Urology - ISSN: 1687-6369/1687-6377
v:2009 Jan-2009 pp:1-6 doi: 10.1155/2009/406012
Abstract: Objectives. Using a urethral device at the fossa
navicularis, bladder pressure during voiding can be estimated by a
minimal invasive technique. This study purposes a new diagnostic
index for patients with lower urinary tract symptoms (LUTSs).
Methods. Fifty one patients presenting with LUTSs were
submitted to a conventional urodynamic and a minimal invasive
study. The results obtained through the urethral device and
invasive classic urodynamics were compared. The existing bladder
outlet obstruction index (BOOI) equation that classifies men with
LUTSs was modified to allow minimal invasive measurement of
isovolumetric bladder pressure in place of detrusor pressure at
maximum urine flow. Accuracy of the new equation for
classifying obstruction was then tested in this group of men.
Results. The modified equation identified men with obstruction
with a positive predictive value of 68% and a negative predictive
Sinopse da FEEC
exact Euclidean medial axis (MA) is also sufficient for
reconstruction and centered. It no longer preserves homotopy but it
can be combined with a homotopic thinning to generate homotopic
skeletons. The thinness of the MA, however, may be discussed. In
this paper, we present the definition of the exact Euclidean medial
axis in higher resolution, which has the same properties as the MA
but with a better thinness characteristic, against the price of rising
resolution. We provide and prove an efficient algorithm to
compute it.
Keywords: Medial axis; Skeleton; Euclidean distance
value of 70%, with an overall accuracy of 70%. Conclusions. The
proposed equation can accurately classify over 70% of men
without resorting to invasive pressure flow studies. We must now
evaluate the usefulness of this classification for the surgical
treatment of men with LUTSs.
Computer Engineering
Constructive learning neural network applied to
identification and control of a fuel-ethanol
fermentation process
Luiz Augusto da Cruz Meleiro, Fernando José Von Zuben, Rubens
Maciel Filho
Engineering Applications of Artificial Intelligence - ISSN: 09521976
v:22 n:2 Mar-2009 pp:201-215 doi:
10.1016/j.engappai.2008.06.001
Abstract: In the present work, a constructive learning algorithm
was employed to design a near-optimal one-hidden layer neural
network structure that best approximates the dynamic behavior of
a bioprocess. The method determines not only a proper number of
hidden neurons but also the particular shape of the activation
function for each node. Here, the projection pursuit technique was
applied in association with the optimization of the solvability
condition, giving rise to a more efficient and accurate
computational learning algorithm. As each activation function of a
hidden neuron is defined according to the peculiarities of each
approximation problem, better rates of convergence are achieved,
guiding to parsimonious neural network architectures. The
proposed constructive learning algorithm was successfully applied
to identify a MIMO bioprocess, providing a multivariable model
that was able to describe the complex process dynamics, even in
long-range horizon predictions. The resulting identification model
was considered as part of a model-based predictive control
strategy, producing high-quality performance in closed-loop
experiments.
Keywords: Bioprocess identification,
Constructive neural
networks, Dynamic simulation, Fermentation process, Model
predictive control
Discrete 2D and 3D Euclideabn Medial Axis in
Hidher Resolution
André Vital Saúde, Michel Couprie, Roberto de Alencar Lotufo
Image and Vision Computing - ISSN: 0262-8856
v:27 n:4 Mar-2009 pp:354-363 doi: 10.1016/j.imavis.2008.05.007
Abstract: The notion of skeleton plays a major role in shape
analysis. Some usually desirable characteristics of a skeleton are:
centered, thin, homotopic, and sufficient for the reconstruction of
the original object. The Euclidean medial axis presents all these
characteristics in a continuous framework. In the discrete case, the
exact Euclidean medial axis (MA) is also sufficient for
reconstruction and centered. It no longer preserves homotopy but it
can be combined with a homotopic thinning to generate homotopic
skeletons. The thinness of the MA, however, may be discussed. In
this paper, we present the definition of the exact Euclidean medial
axis in higher resolution, which has the same properties as the MA
but with a better thinness characteristic, against the price of rising
resolution. We provide and prove an efficient algorithm to
compute it.
Keywords: Medial axis; Skeleton; Euclidean distance
Discrete 2D and 3D euclidean medial axis in higher
resolution
André Vital Saúde, Michel Couprie, Roberto de Alencar Lotufo
Image and Vision Computing - ISSN: 0262-8856
v:27 n:4 Mar-2009 pp:354-363 doi:
doi:10.1016/j.imavis.2008.05.007
Abstract: The notion of skeleton plays a major role in shape
analysis. Some usually desirable characteristics of a skeleton are:
centered, thin, homotopic, and sufficient for the reconstruction of
the original object. The Euclidean medial axis presents all these
characteristics in a continuous framework. In the discrete case, the
Neural Network Ensembles: Immune-Inspired
Approaches to the Diversity of Components
Rodrigo Pasti, Leandro Nunes de Castro Silva, Guilherme Palermo
Coelho, Fernando José Von Zuben
Natural Computing - ISSN: 1567-7818
v:1 n:0 Apr-2009 pp:1-29 doi: 10.1007/s11047-009-9124-1
Abstract: This work applies two immune-inspired algorithms,
namely opt-aiNet and omni-aiNet, to train multi-layer perceptrons
(MLPs) to be used in the construction of ensembles of classifiers.
The main goal is to investigate the influence of the diversity of the
set of solutions generated by each of these algorithms, and if these
solutions lead to improvements in performance when combined in
ensembles. omni-aiNet is a multi-objective optimization algorithm
and, thus, explicitly maximizes the components’ diversity at the
same time it minimizes their output errors. The opt-aiNet
algorithm, by contrast, was originally designed to solve singleobjective optimization problems, focusing on the minimization of
the output error of the classifiers. However, an implicit diversity
maintenance mechanism stimulates the generation of MLPs with
different weights, which may result in diverse classifiers. The
performances of opt-aiNet and omni-aiNet are compared with each
other and with that of a second-order gradient-based algorithm,
named MSCG. The results obtained show how the different
diversity maintenance mechanisms presented by each algorithm
influence the gain in performance obtained with the use of
ensembles.
Keywords: Ensembles of classifiers - Diversity of components Artificial immune systems - Multi-layer perceptrons - Multiobjective optimization
On the Relationships Betwen Blind Equalization
and Blind Source Separation - Part I: Foundations
Romis Ribeiro de Faissol Attux, Aline de Oliveira Neves, Leonardo
T. Duarte, Ricardo Suyama, Cynthia Cristina Martins Junqueira,
Leandro Elias Paiva Rangel, Tiago Macedo Dias, João Marcos
Travassos Romano
Journal of Communicacion and Information Systems - ISSN: 19806604
v:22 n:1 Apr-2009 pp:41-52
Abstract: The objective of this two-part work is to present and
discuss the relationships between the problems of blind
equalization and blind source separation. This first part, which is
essentially a tutorial, begins with a systematic exposition of the
basic concepts that form the core of equalization theory, starting
from the fundamental idea that characterizes the zero-forcing
solution and reaching, after an explanation of the supervised
Wiener paradigm, an analysis of the unsupervised or blind
techniques. Afterwards, the problem of blind source separation and
the main approaches to solving it are studied; important concepts
are discussed, such as those of principal component analysis
(PCA), independent component analysis (ICA) and strategies
founded on bases as diverse as the use of mutual information as a
measure of independence, the idea of nongaussianity and the
employment of the classical process of estimation via the method
of maximum-likelihood.
Keywords: Adaptive Filtering, Blind Equalization, Blind
Source
Boletim Acadêmico da FEEC-Unicamp - Vol. 2 número 1
3
On the Relationships Betwen Blind Equalization
and Blind Source Separation - Part II: Relationships
Romis Ribeiro de Faissol Attux, Aline de Oliveira Neves, Leonardo
T. Duarte, Ricardo Suyama, Cynthia Cristina Martins Junqueira,
Leandro Elias Paiva Rangel, Tiago Macedo Dias, João Marcos
Travassos Romano
Journal of Communicacion and Information Systems - ISSN: 19806604
v:22 n:1 Apr-2009 pp:53-61
Abstract: The objective of this two-part work is to present and
discuss the relationships between the problems of blind
equalization and blind source separation. Both tasks appear, at first
sight, to be essentially distinct, since equalization theory was
developed mainly under single-input / single-output (SISO) and
single-input/ multiple-output (SIMO) models, whereas the very
idea of source separation strongly suggests the need for
considering models with multiple inputs and multiple outputs
(MIMO). However, in this second part, equivalences between the
Benveniste-Goursat-Ruget theorem and the approach to blind
source separation based on maximum-likelihood, between the
Shalvi-Weinstein techniques and the separation methods that
employ kurtosis and, finally, between the Bussgang algorithms and
the ICA tools built from concepts such as negentropy and
nonlinear principal component analysis are indicated. Finally,
some connections previously unexplored in the literature are
presented that are derived from ideas such as that of temporality
and that of considering the parallels existing between a two-stage
(magnitude and phase) equalization procedure and the classical
pair PCA / ICA.
Keywords: Adaptive Filtering, Blind Equalization, Blind
Source Separation, Independent Compon
Query Expansion Using an Immune-inspired
Biclustering Algorithm
Pablo Alberto Dalbem de Castro, Fabrício Olivetti de França,
Hamilton Melo Ferreira, Guilherme Palermo Coelho, Fernando
José Von Zuben
Natural Computing - ISSN: 1567-7818
v:1 n:0 Apr-2009 pp:1-24 doi: 10.1007/s11047-009-9127-y
Abstract: Query expansion is a technique utilized to improve the
performance of information retrieval systems by automatically
adding related terms to the initial query. These additional terms
can be obtained from documents stored in a database. Usually, this
task is performed by clustering the documents and then extracting
representative terms from the clusters. Afterwards, a new search is
performed in the whole database using the expanded set of terms.
Recently, the authors have proposed an immune-inspired
algorithm, namely BIC-aiNet, to perform biclustering of texts.
Biclustering differs from standard clustering algorithms in the
sense that the former can detect partial similarities in the attributes.
The preliminary results indicated that our proposal is able to group
similar texts effectively and the generated biclusters consistently
presented relevant words to represent a category of texts.
Motivated by this promising scenario, this paper better formalizes
the proposal and investigates the usefulness of the whole
methodology on larger datasets. The BIC-aiNet was applied to a
set of documents aiming at identifying the set of relevant terms
associated with each bicluster, giving rise to a query expansion
tool. The obtained results were compared with those produced by
two alternative proposals in the literature, and they indicate that
these techniques tend to generate complementary results, as a
consequence of the use of distinct similarity metrics.
Keywords: Biclustering - Artificial immune systems Information retrieval - Query expansion
4
Electrical Energy
A new method for redundancy analysis of
measurements applied to three-phase state
estimation
Madson Côrtes de Almeida, Eduardo Nobuhiro Asada, Ariovaldo
Verandio Garcia
Electric Power Systems Research - ISSN: 0378-7796
v:79 n:1 Jan-2009 pp:234-238 doi: 10.1016/j.epsr.2008.06.006
Abstract: In this paper, a new method based on the properties of
the Gram matrix is proposed to verify the redundancy of
measurements in three-phase state estimation. The Gram matrix is
constructed using rows of the measurement Jacobian matrix as
vectors. The method can be used for measurement systems
planning or updating of three-phase networks so that the overall
system remain observable even under possible branch
contingencies and loss of measurements. It is a fast and robust
numerical method based on the Gram matrix factorization that is
easy to implement. A small numerical example that shows the
application of the method is presented.
Keywords: Observability analysis; Three-phase system;
Measurement redundancy.
A new method for redundancy analysis of
measurements applied to three-phase state
estimation
Madson Côrtes de Almeida, Eduardo Nobuhiro Asada, Ariovaldo
Verandio Garcia
Electric Power Systems Research - ISSN: 0378-7796
v:79 n:1 Jan-2009 pp:234-238 doi: 10.1016/j.epsr.2008.06.006
Abstract: In this paper, a new method based on the properties of
the Gram matrix is proposed to verify the redundancy of
measurements in three-phase state estimation. The Gram matrix is
constructed using rows of the measurement Jacobian matrix as
vectors. The method can be used for measurement systems
planning or updating of three-phase networks so that the overall
system remain observable even under possible branch
contingencies and loss of measurements. It is a fast and robust
numerical method based on the Gram matrix factorization that is
easy to implement. A small numerical example that shows the
application of the method is presented.
Keywords: Observability analysis; Three-phase system;
Measurement redundancy
A New Method to H2 Robust Filter Design
Rafael de Castro Duarte Martins, José Claudio Geromel
Linear Algebra and its Applications - ISSN: 0024-3795
v:430 n:1 Jan-2009 pp:145-154 doi: 10.1016/j.laa.2008.07.026
Abstract: In this paper a new method to robust filter design is
proposed. Both continuous and discrete time settings are
considered for systems subject to polytopic parameter uncertainty.
Lower and upper bounds of the true cost are determined in order to
evaluate the degree of sub-optimality of the proposed robust filter.
The design method is based on the parametrization of all robust
filters as a convex combination of Kalman filters associated to
each vertex of the uncertainty domain. Among all feasible filters,
the one minimizing a guaranteed cost of the estimation error is
determined by a pure convex programming problem, expressed in
terms of linear matrix inequalities (LMIs). The order of the robust
filter is generally greater than the order of the plant, a fact that
contributes to reduce conservatism. The proposed design technique
is compared with other methods available in the literature. In
several examples solved the proposed method outperforms all
other designs.
Keywords: Kalman filter; Robust filtering; Linear matrix
inequalities
Sinopse da FEEC
Adaptive Hybrid Genetic Algorithm for Technical
Loss Reduction in Distribution Networks Under
Variable Demands
Leonardo Mendonça Oliveira de Queiroz, Christiano Lyra Filho
IEEE Transactions on Power Systems - ISSN: 0885-8950
v:24 n:1 Feb-2009 pp:445-453 doi: 10.1109/TPWRS.2008.2009488
Abstract: In power distribution networks the load varies within
any given time frame. It may, therefore, seem that a good approach
to reduce losses would be the solving of a network reconfiguration
problem to suit each of the significant load variations. However,
frequent changes in configuration can trigger outages or cause
transient problems; they are best avoided. A recent formulation of
this problem explicitly considers load variations and proposes to
restrain frequent reconfigurations by assuming that network
topologies will remain unchanged for a given planning period.
This formulation leads to a much larger optimization problem than
that traditionally used for network reconfiguration; moreover, it
requires a new approach to optimization which is capable of
dealing with energy flows instead of only instantaneous power
flows. Such an approach is proposed in this paper, which discusses
the design of an adaptive hybrid genetic algorithm that fulfills
these new requirements. Key concepts in evolutionary
computation and analysis of distribution systems are explored to
develop this new algorithm. Application to real case studies
certifies its benefits.
Keywords: Distribution of electric power; genetic algorithms;
hybrid genetic algorithms; loss reduction; network;
reconfiguration; technical losses; variable demands
Dimensionamento de Dissipadores para
Semicondutores - Parte Final
found that strong positive feedback gain will destabilize the
distribution generator when the power transferred from the
distribution system to the DG local load is small.
Keywords: Distributed generation; inverter-based generator;
positive feedback anti-islanding; voltage stability
Modeling and circuit-Based Simulation of
Photovoltaic Arrays
Marcelo Gradella Villalva, Jonas Rafael Gazoli, Ernesto Ruppert
Filho
Eletrônica de Potência - ISSN: 1414-8862
v:14 n:1 Feb-2009 pp:35-45
Abstract: This paper presents an easy and accurate method of
modeling photovoltaic arrays. The method is used to obtain the
parameters of the array model using information from the
datasheet. The photovoltaic array model can be simulated with any
circuit simulator. The equations of the model are presented in
details and the model is validated with experimental data. Finally,
simulation examples are presented. This paper is useful for power
electronics designers and researchers who need an effective and
straightforward way to model an simulate photovoltaic arrays.
Keywords: Array, circuit, equivalent, model, modeling,
photovoltaic, PV, simulation.
Security constrained optimal active power flow via
network model and interior point method
Anibal T. de Azevedo, Aurelio R.L. Oliveira, Carlos Alberto de
Castro Jr., Secundino Soares Arantes
Sba Controle & Automação - ISSN: 0103-1759
v:20 n:2 Apr-2009 pp:206-216 doi: 10.1590/S010317592009000200008
Abstract: This paper presents a new formulation for the security
constrained optimal active power flow problem which enables the
representation of three basic constraints: branch outage, generator
outage and multiple equipment congestion. It consists of a network
model with additional linear equality and inequality constraints
and quadratic separable objective function, which is efficiently
solved by a predictor-corrector interior point method. Sparsity
techniques are used to exploit the matricial structure of the
problem.Case studies with a 3,535- bus and a 4,238-branch
Brazilian power system are presented and discussed, to
demonstrate that the proposed model can be efficiently solved by
an interior point method, providing security constrained solutions
in a reasonable time.
Keywords: Security, active power dispatch, optimal power
flow, network model, power flow controls, interior point method
José Antenor Pomílio
Saber Eletrônica - ISSN: 0101-6717
v:434 n:44 Fev-2009 pp:26-30
Resumo: Trata-se de uma discussão sobre o projeto térmico
associado a dispositivos semicondutores de potência. Parte-se do
cálculo ou estimativa da potência dissipada, passando pelos
dispositivos de dissipação de calor e pelos métodos de redução da
resistência térmica dos dissipadores. São analisadas situações de
temperatura média (resistência térmica) e de transitórios
(impedância térmica).
Palavras-chave: eletrônica de potência, dissipadores, fontes
chaveadas
Dimensionamento de Dissipadores para
Semicondutores - Parte I
José Antenor Pomílio
Saber Eletrônica - ISSN: 0101-6717
v:433 n:44 Fev-2009 pp:10-15
Resumo: Trata-se de uma discussão sobre o projeto térmico
associado a dispositivos semicondutores de potência. Parte-se do
cálculo ou estimativa da potência dissipada, passando pelos
dispositivos de dissipação de calor e pelos métodos de redução da
resistência térmica dos dissipadores. São analisadas situações de
temperatura média (resistência térmica) e de transitórios
(impedância térmica).
Palavras-chave: eletrônica de potência, dissipadores, fontes
chaveadas
Switched State Feedback Control for Continuous
Time Uncertain Systems
Grace Silva Deaecto, José Claudio Geromel
Automatica - ISSN: 0005-1098
v:45 n:2 Feb-2009 pp:593-597 doi:
10.1016/j.automatica.2008.10.010
Abstract: This paper is concerned to design a switched state
feedback robust control for continuous-time systems subject to
norm bounded uncertainty. As important features of the proposed
design method, we mention that it can handle a general LFT
structure for the uncertainty and it is based on stability conditions
that can be numerically solved by means of LMIs and a line
search. Moreover, the switching rule as well as the state feedback
gains are determined from the minimization of a guaranteed cost
function derived from a multi-objective criterion. The theoretical
results are illustrated with an academic example.
Keywords: Switched linear systems; Robust control; LMI
Influence of Voltage Positive Feedback AntiIslanding Scheme on Inverter-Based Distributed
Generator Stability
Xiaoyu Wang, Walmir de Freitas Filho
IEEE Transactions on Power Delivery - ISSN: 0885-8977
v:24 n:2 Apr-2009 pp:972-973 doi: 10.1109/TPWRD.2009.2013373
Abstract: This letter investigates the influence of the voltage
positive feedback anti-islanding scheme on the stability of
inverter-based distributed generators (DGs). Modal analysis is
used to determine the relationship between the positive feedback
gain of the anti-islanding control and the stability limit. It was
The Complex Controller for Three−Phase Induction
Motor Direct Torque Control
Alfeu Joãozinho Sguarezi Filho, Ernesto Ruppert Filho
Controle & Automação - ISSN: 0103-1759
v:20 n:2 Apr-2009 pp:256-262 doi: 10.1590/S010317592009000200012
5
Abstract: This paper proposes a design and tuning method for a
complex gain controller, based on the three-phase induction motor
mathematical model complex transfer function to be used in the
direct torque control at low speed which is a problem so far. The
design and tuning of the complex gain is done by using the closed
loop system frequency-response function. Experimental results are
presented to validate the controller and operation at low speed is
also explored.
Keywords: Complex gain controller, Complex transfer function,
Induction motor, Direct torque control.
Telecommunication and Telematic
Achievable rates of DSL with crosstalk cancellation
Danilo Zanatta Filho , Rafael Ferrari , Murilo Bellezoni Loiola,
Ricardo Suyama, Glauco Cesar Crystal Pereira Simões, Boris
Dortschy, Renato da Rocha Lopes
European Transactions on Telecommunications - ISSN: 1124318X
v:20 n:1 Jan-2009 pp:81-86 doi: 10.1002/ett.1345
Abstract: Crosstalk is one of the main limiting factors in the data
rates achievable by digital subscriber line (DSL) systems, and
several algorithms have been proposed to mitigate this impairment.
In this paper, we compare the achievable rates of binders under
different crosstalk-mitigating techniques. When computing these
rates, we also compare two different power constraints: either on
the total power in the binder or on the power in each twisted wire
pair. We will see that, for the scenarios considered in this paper,
the fact that the signals are jointly processed in one or both ends of
the DSL link leads to roughly the same performance, which can be
far superior to that of systems with no cooperation between the
users. Both power constraints also lead to similar achievable rates.
Keywords: Crosstalk Cancellation, DSL systems.
An energy efficiency model for adaptive and
custom error control schemes in bluetooth sensor
networks
João Henrique Kleinschmidt; Walter da Cunha Borelli; Marcelo
Eduardo Pellenz
AEÜ International Journal of Electronics and Communications ISSN: 1434-8411
v:63 n:3 Mar-2009 pp:188-199 doi: 10.1016/j.aeue.2008.01.001
Abstract: This paper analyzes the effect of custom error control
schemes on the energy efficiency in Bluetooth sensor networks.
An analytical model is presented to evaluate the energy efficiency
metric, which considers in just one parameter the energy and
reliability constraints of wireless sensor networks. New packet
types are introduced using some error control strategies in the
AUX1 packet, where custom coding can be implemented. Two
adaptive techniques are proposed that change the error control
strategy based on the number of hops traversed by a packet
through the network. A packet selection strategy based on channel
state is proposed for sensor networks with different channel
conditions. Performance results are obtained through analysis and
simulation in Nakagami-m fading channels for networks with
different number of hops and channel conditions.
Keywords: Bluetooth; Error control; Sensor networks; Energy
efficiency
Análises Comparativas entre Esquemas de
Codificação Turbo Convolucional
Ricardo Barroso Leite, Ana Lucia Mendes C. S. da Silva, Alcides da
Costa Lino Neto, Natasha Bortolozo Menèndez, Yuzo Iano
Revista Ciência e Tecnologia - ISSN: 1677-9649
v:11 n:19 Jan-2009 pp:1-16
Resumo: Os códigos corretores de erros diretos são necessários
para se elevar a confiabilidade na transmissão de informação, que
é submetida a distorções destrutivas. Com a codificação de canal é
possível se atingir uma redução significativa na potência de
transmissão, mantendo-se a qualidade e fidelidade dos dados
recebidos. Neste contexto, esquemas de codificação Turbo vêm
6
recebendo destaque dado o desempenho próximo ao limite teórico
de Shannon. Neste artigo são apresentadas comparações entre
códigos Turbo convolucional série e paralelo em canal AWGN,
variando-se parâmetros como tamanho de frame, número de
iterações e taxas de puncionamento. Esses resultados podem
auxiliar diversas aplicações, como TV digital, transmissão via
satélite e telefonia móvel.
Palavras-chave:
Codificação
Turbo
Convolucional,
Codificação de Canal, Desempenho de Codificadores.
Avaliação da qualidade de serviço das VPN IP
MPLS para redes de nova geração (NGN)
Adão Boava, Yuzo Iano
v:11 n:19 Jan-2009 pp:1-15
Resumo: As tecnologias VPN/MPLS e DiffServ têm sido
propostas para o provimento de qualidade de serviço(QoS) para a
próxima geração das VPNs. Este artigo apresenta os resultados da
avalição da QoS baseada nestas tecnologias. O trabalho proposto
utiliza um ambiente de teste desenvolvido para este artigo com o
objetivo de validar a implementação de VPNs MPLS com
DiffServ. Foram realizados testes voltados para a geração de dados
referentes a qualidade de serviço. Esses dados permitiram a
realização de análises do desempenho das VPNs MPLS. O artigo
apresenta também a implementação da RFC 2547. De forma geral,
o artigo é capaz de representar o desenvolvimento e a avaliação de
VPNs MPLS para várias classes com qualidade de serviço fim a
fim, as quais transportam tráfegos de diversas aplicações: tráfego
melhor esforço (best effort), tráfego com prioridades (AF1, AF2,
AF3, AF4) e tráfego de voz (EF)
Palavras-chave: VPN, MPLS, QoS, DiffServ e CoS
Canal de Interactividad
Rodrigo Teixeira Sales, Luis Geraldo Pedroso Meloni
Revista da SET - ISSN: 1980-2331
v:19 n:1 Jan-2009 pp:70-72
Abstract: Este artículo de la serie sobre el Sistema Brasileño de
Televisión Digital presenta la arquitectura de canal de retorno y las
tecnologías de comunicación de redes aplicables. La especificación
técnica está disponible en la Norma ABNT NBR 15607, y
distribuida en tres partes (1) Protocolos, interfaces físicas e
interfaces de software, ya publicada, (2) Dispositivos externos e
(3) Interfaces de configuración para las tecnologías de acceso, en
elaboración. La concepción inicial de interactividad en la
televisión digital está asociada a la posibilidad de comunicación de
datos de las estaciones receptoras con los aplicativos
eventualmente disponibles a través de la señal de difusión de una
emisora. La comunicación de la emisora con los receptores se
realiza a partir de una estación transmisora que envía los datos en
broadcasting a una gran cantidad de receptores simultáneamente.
Por otro lado, la transmisión de datos del receptor para la emisora,
se realiza por un subsistema, comúnmente llamado de canal de
retorno o canal de interactividad, que en el SBTVD tal
comunicación de interactividad es bidireccional por medio del
protocolo TCP/IP.
Keywords: Return channel, interactive channel, Integrated
Services Digital Broadcasting - Terrestrial - ISDB-T
Codificação Turbo Convolucional, Codificação de
Canal, Desempenho de Codificadores
Rogério Seiji Higa, Yuzo Iano
v:11 n:19 Jan-2009 pp:1-16
Resumo: A interpolação de formas consiste em gerar uma forma
intermediária a partir de dois polígonos, isto é, uma mistura das
duas formas. Este processo apesar de ser relativamente fácil para
uma pessoa, é bem complexo para um computador. Esta técnica
tem aplicações em várias áreas como a computação gráfica,
animação, visualização científica e modelagem. O método
apresentado consiste em usar uma métrica de polígonos para fazer
Sinopse da FEEC
uma correspondência inicial, compensando a rotação entre os
polígonos, e utilizar uma função de custo para fazer o resto da
correspondência. Para melhorar o resultado em certas formas, um
método de decomposição de polígonos é incorporado ao processo.
No processo de correspondência e interpolação são utilizados
lados no lugar dos pontos, evitando assim o surgimento de lados
de comprimento zero
Palavras-chave: Interpolação de Formas,
polígonos,
animação, métrica, decomposição.
General Exact and Accurate Approximate
Formulations for the Crossing Rates of Multibranch
Diversity Receivers over Non-Identical Correlated
Weibull Channels
Daniel Benevides da Costa, Michel Daoud Yacoub, José Cândido
Silveira Santos Filho
IEEE Transactions on Wireless Communications - ISSN: 15361276
v:8 n:3 Mar-2009 pp:1188-1193 doi: 10.1109/TWC.2008.080659
Abstract: General exact expressions for the average level
crossing rate (LCR) of multibranch selection (SC), equal-gain
(EGC), and maximal-ratio (MRC) combiners operating over nonidentical correlated Weibull fading channels are provided. They
are given in terms of finite-range multifold integrals. Our exact
formulations generalize those obtained recently in the literature for
the dual-branch case. The exact solution requirements are then
loosened to allow for simpler accurate approximate expressions.
They appear in a fairly simple closed-form fashion, for the SC, and
still as multiple integrals, for the EGC and MRC, but with much
simpler integrands, which drastically reduces the calculation time.
Sample numerical results are discussed by specializing the general
expressions to a space-diversity system using three collinear
horizontally spaced omnidirectional antennas at the mobile station.
Keywords: Approximate formulations,
Weibull fading,
correlation model, level crossing rate, multibranch receivers
Impacto do Aumento da Dimensionalidade no
Desempenho de Códigos Turbo Produto
Natasha Bortolozo Menèndez, Alcides da Costa Lino Neto, Ricardo
Barroso Leite, Fernando S. Silva , Yuzo Iano, André Filgueiras de
Araujo
v:11 n:19 Jan-2009 pp:1-6
Resumo: Os códigos FEC (Forward Error Correction Codes) são
hoje indispensáveis à manutenção da confiabilidade da informação
na codificação de canal, dentre eles destacando-se os Códigos
Turbo Produto. O presente artigo analisou o impacto do aumento
da dimensionalidade no desempenho dos Códigos Turbo Produto,
apresentando comparações entre os diversos esquemas. Os
resultados obtidos revelam que, para os parâmetros testados, a
eficiência do código (taxa de erros de bit para um mesmo valor de
Eb/N0) melhora com o aumento da dimensionalidade somente até
o código 4D. Os resultados da análise do efeito da variação de taxa
de código quanto se está trabalhando com códigos 4D também foi
abordado.
Palavras-chave: Códigos Turbo Produto; Códigos Corretores
de Erros; Códigos de Paridade Simples
On the Performance of Promising Dirac Video
Codec
André Filgueiras de Araújo, Yuzo Iano
v:11 n:19 Jan-2009 pp:1-7
Abstract: Video source coding has become a theme of major
importance in the communications domain, due to the growing use
of digital video and to its potential for greatly reducing the impact
on bandwidth needs. This paper investigates the recently released
promising state-of-the-art video codec Dirac, based on wavelet
transform. It is considered comparatively with respect to the wellknown H.264/AVC scheme, one of the best methods for encoding
video. They are compared in terms of visual quality, latency and
bit rate.
Keywords: codec, Dirac, H.264, source coding, video
compression, wavelets.
On the Simulation and Correlation Properties of
Phase-Envelope Nakagami Fading Processes
José Cândido Silveira Santos Filho, Michel Daoud Yacoub
IEEE Transactions on Communications - ISSN: 0090-6778
v:57 n:4 Apr-2009 pp:906-909 doi:
10.1109/TCOMM.2009.04.070195
Abstract: The aim of this Letter is twofold: to propose a
simulator for both the phase and the envelope of Nakagami fading
channels with arbitrary parameters and to derive precise closedform approximations to the correlation functions of the Nakagami
envelope, phase, and quadrature components.
Keywords: Correlation, fading channels, Nakagami fading,
rank statistics, simulation
On the sum capacity of a T-user N-frequency
multiple access channel with noise
Manish Sharma, Jaime Portugheis
European Transactions on Telecommunications - ISSN: 1124318X
v:1 n:1 Feb-2009 pp:1-6 doi: 10.1002/ett.1351
Abstract: In this paper, we investigate the sum capacity of a
noisy multiple access channel (MAC): the T-user N-frequency
noiseless MAC in cascade with a noisy channel. The noisy channel
includes frequency-selective Rayleigh fading and Additive White
Gaussian Noise (AWGN). The receiver may use multiuser
detection (MUD) or single user detection (SUD). We show that
when using SUD, the uniform distribution achieves sum capacity.
Considering MUD and assuming that all users have the same input
distribution, we show through numerical optimisation, that, for
most relevant values of T and N, a product of uniform input
distributions maximises a tight upper bound on sum capacity.
Numerical results were obtained and it was observed that, for fixed
N, there is a value of T which maximises sum capacity. As
expected, the results also show that there is a significant gain in
sum capacity when MUD is used.
Keywords: Channel Capacity, Multiple Access Channels,
Frequency Hopping
On Toric Quantum Codes
Clarice Dias de Albuquerque, Reginaldo Palazzo Jr., Eduardo
Brandani da Silva
International Journal of Pure and Applied Mathematics - ISSN:
0973-1768
v:20 Feb-2009 pp:221-226
Abstract: In this paper we present new toric quantum codes
derived from quadratic forms. The new class of codes is optimum
in the sense that its codeword length is the smallest among the
already known codes. The parameters of the new codes are [[d^2,
2, d]].
Keywords: topological quantum codes,
toric codes,
polyominoes.
Optimization of Generalized 2x2 Mesh Topologies
an Evolutionary Algorithm
Luiz Henrique Bonani do Nascimento, R. Arthur, Felipe Rudge
Barbosa, Romis Ribeiro de Faissol Attux, Edson Moschim
Revista Telecomunicações Inatel(Santa Rita do Sapucaí) - ISSN:
1516-2338
v:12 n:1 Abr-2009 pp:24-29
Resumo: In this work, we propose and analyze a generalized
optimization process for 2x2 mesh topologies based on an
algorithm built with the aid of ideas drawn from the field of
evolutionary computation. In the proposed framework, this
algorithm is employed to minimize a parameter - the average
number of hops - which is particularly relevant from the
standpoints of increasing the effective network capacity and
7
seeking a better traffic distribution insofar as mesh topologies are
concerned. The methodology is simple and can be used for mesh
topologies with a wide range of number of nodes.
Palavras-chave: Optical Networks,
Mesh Topologies,
Evolutionary Computation
Performance investigation of microphotonic-silicon
devices in a field-trial all-optical network
Diego Marconi, Arismar Cerqueira Sodre Jr., J. T. Robinson, N.
Sherwood-Droz, Y. Okawachi, Hugo Enrique Hernandez Figueroa,
M. Lipson, A.L. Gaeta, Hugo L. Fragnito
Optics Communications - ISSN: 0030-4018
v:282 n:5 Mar-2009 pp:849-855 doi: 10.1016/j.optcom.2008.11.018
Abstract: The performance of microphotonic-silicon devices in a
geographically-distributed optical fiber network is experimentally
investigated. Two different devices are tested: an optical filter
based on a silicon ring resonator and an all-optical wavelength
converter based on four-wave mixing in a dispersion-tailored
highly nonlinear silicon waveguide. The evaluation of the devices
is performed by means of eye diagrams and measurements of the
bit error rate.
Keywords: Silicon ring resonators; Silicon waveguides;
Integrated optics; All-optical networks; Field-trial tests
Topological Quantum Codes on Compact Surfaces
with Genus g>2
Clarice Dias de Albuquerque, Reginaldo Palazzo Jr., Eduardo
Brandani da Silva
Journal of Mathematical Physics - ISSN: 0022-2488
v:50 Feb-2009 pp:1-20 doi: 10.1063/1.3081056
Abstract: In this paper we propose a construction procedure of a
class of topological quantum error-correcting codes on surfaces
with genus g_2. This generalizes the toric codes construction. We
also tabulate all possible surface codes with genus 2–5. In
particular, this construction reproduces the class of codes obtained
when considering the embedding of complete graphs Ks, for s_1
mod 4, on surfaces with appropriate genus. We also show a table
comparing the rate of different codes when fixing the distance to
3–5.
Keywords: error correction codes, graph theory, quantum
computing, topology
Uniform Approximation of Infinite Horizon Control
Problems for Nonlinear Systems and Stability of
the Approximating Controls
Eduardo F. Costa, João Bosco Ribeiro do Val
IEEE Transactions on Automatic Control (Print) - ISSN: 00189286
v:54 n:4 Apr-2009 pp:881-886
Abstract: This technical note addresses the approximation of the
infinite horizon problem and the stability of the approximating
controls gener- ' ated by the receding horizon method. The setup
takes into account systems and costs that may be nonlinear and
discontinuous, with possibly state and control constraints, allowing
for a wide range of problems. A detectability notion is introduced
that matches standard regularity conditions such as existence of
bounds for the cost, and does not require any continuity
hypothesis. It is shown that the receding horizon controls
associated with the finite horizon problems are approximating
solutions for the infinite horizon problem, for a large enough
horizon. Exponential stability of the controlled system and
estimates for horizons ensuring stability and approximation of the
infinite horizon problem are also studied.
Keywords: Approximating control ; discrete-time systems ;
model predictive control ; nonlinear systems ; receding horizon
control
8
Articles in proceedings
Automation
A Vibroacoustic Application of Identification and
Control for Linear Time-Varying Systems
Jan De Caigny, Juan Francisco Camino, Ricardo Coração de Leão
Fontoura de Oliveira, Pedro Luis Dias Peres, Jan Swevers
In: Proceedings of the XIII International Symposium on Dynamic
Problems of Mechanics (DINAME 2009)-Almeida, C. A(Ed.) ABCM
Angra dos Reis, RJ Mar-2009
Abstract: This paper presents an application of H2 and H-infinity
gain-scheduled and robust state feedback control for a
time-varying vibroacoustic setup whose dynamics is highly
sensitive to variation in the ambient temperature. An LPV model is
derived for this system using the State-space Model Interpolation
of Local Estimates (SMILE) technique. This approach interpolates
linear time-invariant models estimated at distinct operating
conditions of the system (in this case, different temperatures). The
obtained LPV model is used in recently developed gain-scheduled
and robust H2 and H-infinity synthesis procedures that can
consider a priori known bounds on the rate of parameter variation.
Keywords: Gain-scheduled and robust control; LPV
identification; H2 and H-infinity performance; Linear timevarying systems; Control applications
Interval-Based Evolving Modeling
Daniel Furtado Leite, Pyramo Pires da Costa Júnior, Fernando
Antonio Campos Gomide
In: 2009 IEEE Symposium Series on Computational Intelligence SSCIP - ISBN: 978-1-424427543
Nashville Mar-2009 pp:1-8 doi: 10.1109/ESDIS.2009.4938992
Abstract: This paper introduces a granular, interval-based
evolving modeling (IBeM) approach to develop system models
from a stream of data. IBeM is an evolving rule-based modeling
scheme that gradually adapts its structure (information granules
and rule base) and rules antecedent and consequent parameters
from data (inductive learning). Its main purpose is continuous
learning, self-organization, and adaptation to unknown
environments. The IBeM approach develops global model of a
system using a fast, one-pass learning algorithm, and modest
memory requirements. To illustrate the effectiveness of the
approach, the paper considers actual time series forecasting
applications concerning electricity load and stream flow
forecasting.
Keywords: Granular evolving systems, granular adaptive fuzzy
modeling, interval-based modeling
An Instrumented Sphere for impact and
temperature measurements at orange
packinghouses
Fabiano Fruett, Murilo Nicolau, Marcos David Ferreira, Poliana
Spricigo
In: 6th International Postharvest Symposium
Antalya Apr-2009 pp:181-183
Abstract: An instrumented sphere (IS) was developed and
characterized for mechanical impact and temperature
measurements in fruits during sorting and packing in a packinghouse. The IS was carried out with oranges in a commercial
packinghouse where these fruits were selected, washed, waxed,
dried and boxed in a packing line. During the postharvest process,
temperature, frequency and intensity of impacts were measured
and recorded. These results were compared with a commercial IS
(IRD400) Techmark, Inc., Lansing, (76 mm) [1] which is equipped
with a tri-axial accelerometer. The data obtained from the
instrumented sphere allows determining: (1) the frequency and
intensity of impacts, (2) the transport velocity and (3) the
Sinopse da FEEC
temperature changes in the packing-line. Impacts were measured
as maximum acceleration in G (9.81 m/s2) and temperature in ºC.
The hardware of the developed IS is composed by two biaxial
accelerometers, a temperature sensor, a microcontroller and a USB
module. The accelerometers are MicroElectroMechanical Systems
(MEMS) based on microfabricated capacitors. The range of
measured acceleration is between 0.5 G to 250 G. The
microelectronic temperature sensor is positioned facing the
external boundary surface of the IS and can measure temperature
in the range of 0 ºC to 80 ºC. The low-power microcontroller has a
stand-by operation mode to extend both the battery lifetime and IS
autonomy. The IS can continuous measure impact and temperature
during 120 minutes with a bandwidth of 1 kHz. This autonomy can
be extended whether the configuration of the stand-by mode is
optimized according to the IS utilization. The IS´s software was
developed based on Virtual Instruments designed in LabView®.
This software allows a user-friendly interface with IS. The
measured data are downloaded to the computer using a plug-andplay USB connector.
The impact data obtained from our developed IS were in
agreement with the data obtained from the Techmark IS. Both
spheres recorded impacts from 15 G to 250 G. The temperature
data was especially useful during drying process after wash and
through wax. The developed IS recorded temperatures from 28 ºC
to 35 ºC.
Keywords: Electronic Fruit, Mechanical Damage, Bruising,
Accelerometer, temperature sensor
Photonic crystals and plasmonic structures
recorded by multi-exposure of holographic patterns
Jacson Weber de Menezes, Edmundo da Silva Braga, Lucila Helena
Deliesposte Cescato
In: SPIE Europe Optics + Optoelectronics
Prague, Republica Tcheca Apr-2009 pp:1-3
Abstract: Different tecbnologies can be used for fabrication of
photonic crystals such as: self-assembly of colloidal particles, ebeam lithography (EB), interference lithography (IL) and focused
ion beam (FIE). Among them, the holographic lithography (HL) is
the on1y technique that is able to fabricate both two-dimensional
and three-dimensional photonic crystals, as well as plasmonic
structures, in large areas. In this paper we demonstrate the use of
the multi-exposure of two-beam interference patterns, with
rotation of the sample around different axis, for fabrication of large
areas 2D and 3 D photonic crystals and plasmonic structures.
Using this tecbnique, we achieved aspect ratios of about 4 in 2D
photoresist templates recorded in 1 cm2 glass substrates. In order
to generate the 2D photonic band gap layers and plasmonic
structures, we combine the use the high aspect ratio photoresist
templates with shadow evaporation of appropriated materiais, with
a further lift-off of the photoresist. The opticaI properties of the
recorded structures, both photonic and plasmonic, were measured
to demonstrate the applicability of the technique.
Keywords: Photonic Crystal,
Plasmonics,
Holographic
Lithography
Planar Antenna Array Mutual Coupling
Identification: A Direct Method Applied to QuaseYagi Elements
Carlos Eduardo Capovilla, André Tavora de Albuquerque Silva,
Silvio Ernesto Barbin, Luiz Carlos Kretly
In: 25 Progress in Electromagnetics Research Symposium (PIERS)
Beijing, China Mar-2009 pp:1-6
Abstract: Mutual coupling between adjacent elements is a critical
issue for the design of antenna arrays. In this way, it is important
to know the influence that each type of coupling mechanism
represents in the total mutual coupling. With this objective for a
quasi-Yagi antenna array, four prototypes with special details were
built and tested. Surface waves and free space coupling were
analyzed aiming at proposing a better optimization procedure for
the structure. Concluding, FDTD simulation results for the
currents distribution on the surface of the array are presented.
Keywords: Antenna arrays, Coupling , Quasi-yagi, FDTD
Potential for 1550-nm Broadband Amplification by
Using Different Er3+-Doped Tellurite Fiber
Structures
Reginaldo da Silva, Enver Fernandes Chillcce, Carlos Lenz Cesar,
Luiz C. Barbosa, Aldário Chrestani Bordonalli
In: Optical Fiber Communication Conference and Exposition
(OFC) and National Fiber Optic Engineers Conference (NFOEC)
San Diego Mar-2009 pp:1-6
Abstract: A spectral analysis of two Er3+-doped tellurite fiber
structures pumped at 980-nm is presented. The samples produced
bandwidths in the order of 95 nm around 1550 nm and potential
amplification up to 15 dB.
Keywords: Fiber optics amplifiers and oscillators; Fibers,
erbium; Fiber optics design and fabrication
XPM-based 2R-wavelenght conversion with ULSOA and abrupt-band optical filtering
Cristiano de Mello Gallep, Napoleão dos Santos Ribeiro, Evandro
Conforti
In: XXVI PIERS - Progress In Electromagnetics Research
Symposium
Moscou, Rússia Jan-2009 pp:1-5
Abstract: Optical carrier s filtering after SOA-induced XPM is
used to promote wavelength conversion with re-shape capabilities.
Successful experimental results were obtained for RZ signal at
7Gbps, pointing to optimal performance at about 25 Gbps.
Keywords: Wavelenght conversion; semiconductor optical
amplifier
A Network Architecture for Large Mobile Roborics
Environments
Daniel de Haro Moraes, Paulo Rodolfo da Silva Leite Coelho,
Eliane Gomes Guimarães, Eleri Cardozo, Thienne de Melo e Silva
Mesquita Johnson, Fernanda Cristina Adabo Atizani
In: Second International Conference on Robot Communication and
Coordination - ROBOCOMM´09
Odense Mar-2009 pp:1-6
Abstract: Mobile robotics environments must adopt networking
solutions that provide secure and reliable communications for the
mobile robots across wide areas such as hospitals, factories, farms,
etc. This paper proposes a network architecture for large mobile
robotic environments built above the existing networking
infrastructures. The architecture builds an overlay network above
the already deployed network. The overlay network must fulfill the
requirements demanded by mobile robotic applications, mainly,
communication continuity during handover, security, and quality
of service. A prototype of this architecture was implemented and
evaluated in a mobile robotic environment composed of Pioneer
P3-DX mobile robots accessed through the Internet. Results from
simulation show that the architecture scales well in larger
networking scenarios.
Keywords: Mobile Robotics Environment, Large Network
Environments, Overlay Networks, Wireless Handover.
A Network Architecture for Providing Micromobility in MPLS/GMPLS Networks
Tomás Antônio Costa Badan, Eduardo Nicola Ferraz Zagari,
Rodrigo Chavez Monteiro do Prado, Eleri Cardozo, Mauricio
Ferreira Magalhães, Jose Aparecido Carrilho, Rossano Pablo
Pinto, André Luiz Amorim Berenguel, Daniel de Haro Moraes,
Thienne de Melo e Silv
In: IEEE Wireless Communications & Networking Conference IWCNC
Budapest Apr-2009 pp:1-6
9
Abstract: The Mobile Plane Architecture (MPA) is a network
architecture that provides micro-mobility in a network-centric
way, that is, the burden of supporting micro-mobility is placed on
the network and not on the mobile nodes. MPA employs an
overlay network above an IPv4 or IPv6 transport network in order
to direct traffic to the mobile nodes. The overlay network is built
by establishing point-to-multipoint (P2MP) tunnels through the
transport network. This paper presents an implementation of MPA
over MPLS/GMPLS networks. It is shown that the combination of
P2MP tunneling with label stacking is an effective way for
providing mobility services in MPLS/GMPLS transport networks.
Results obtained in a lab-sized network are presented as well.
Keywords: Keywords-MPLS, Wireless Internet, Micro-Mobility
A New Application for 3D-Snakes - Modelling
Electrical Discharges
Gilmario Barbosa dos Santos, Sidney Pinto da Cunha, Clesio Luiz
Tozzi
In: VISAPP 2009 - 4th International Conference on Computer
Vision Theory and Applications. - ISBN: 978-989-8111-69-2
Lisboa, Portugal Feb-2009 pp:546-553
Abstract: A new approach for modelling electrical discharges is
proposed. To this purpose, an active contour named 3Dsnake is
used that is geometrically represented by a B-spline which evolves
in 3D space constrained by internal and external energies. More
specifically, this external energy come from a pair of images. This
new model is much less dependent on determination of
homologous points than the approaches found in the literature for
recovering 3D geometry of electrical discharges. In addition, the
proposal discussed here is capable of tracking the evolution of the
electrical discharge taking into account the time dependence
between consecutive pairs of frames in two videos.
Keywords: B-spline, snakes, 3D image reconstruction, camera
calibration, electrical discharges characterization.
A Simple Approach for Estimation of Execution
Effort of Functional Test Cases
Daniel Guerreiro E Silva, Bruno Teixeira de Abreu, Mario Jino
In: 2nd International Conference on Software Testing, Verification,
and Validation - ICST 2009
Denver, Colorado Apr-2009 pp:289-298
Abstract: Planning and scheduling of testing activities play a key
role for any independent test team that performs tests for different
software systems, pertaining to different development teams.
Based on the work experience with several software systems
within the scope of one real-world project, we propose an
alternative approach that focuses on team efficiency to estimate the
execution effort of a test case suite. To assess the validity of the
approach data collected on test activity along one year was used.
The approach is simpler to use than current methods, requiring less
effort to apply; furthermore, it can provide the test team good
estimates even using a small amount of data.
Keywords: software testing, estimation of test execution effort,
functional test, team efficiency.
Context-Based Name Resolution Service for the
Next-Generation Internet
Rodolfo da Silva Villaça, Fábio Luciano Verdi, Mauricio Ferreira
Magalhaes
In: 28th Conference on Computer Communications - INFOCOM
2009
Rio de Janeiro Apr-2009 pp:1-6
Abstract: With the advent of new communication technologies
and the ubiquity of wireless networks, computing devices have
become portable and mobile, increasing the need to interconnect
them. The new generation of applications tend to be ubiquitous
and context-aware. In the current Internet, the existing name
resolution service, the DNS, has a key role, since most of the
applications make use of a name resolution to obtain the IP address
of a host. However, it is proven that the DNS does not adequately
10
support the requirements of the new generation of applications.
This paper presents an architecture for a context based name
resolution service, along with a review of its main concepts and
related works.
Design and Implementation of a Network-Centric
Micro-Mobility Architecture
Eduardo Nicola Ferraz Zagari, Rodrigo Chavez Monteiro do
Prado, Tomás Antônio Costa Badan, Eleri Cardozo, Mauricio
Ferreira Magalhães, José Aparecido Carrilho, Rossano Pablo
Pinto, André Luiz Amorim Berenguel, Daniel de Haro Moraes,
Tiago Marchetti Dolphi
Abstract: This paper presents the design and implementation of
the Mobility Plane Architecture (MPA). MPA is a network
architecture that provides micro-mobility in a network-centric
way, that is, the burden of supporting micro-mobility is placed on
the network and not on the mobile nodes. The implementation
employs RSVP-TE to establish IP/IP and MPLS pointtomultipoint tunnels in order to direct traffic to the mobile nodes.
DHCP is used for tracking the mobile node locations and RSVPTE opaque data carries the location information to install routes to
them. Results obtained in a lab-sized network and some
quantitative comparisons between MPA and other related work are
presented as well.
Keywords: Wireless Internet, IP Mobility, Micro-Mobility
Domain Identifiers in a Next Generation Internet
Architecture
Rafael Pasquini, Fábio Luciano Verdi, Mauricio Ferreira
Magalhães
In: IEEE Wireless Communications & Networking Conference IWCNC 09
Budapest-HUNGRIA Apr-2009 pp:1-6
Abstract: In this paper we make the domain entity a first class
citizen. The concept of Domain Identifiers (DIDs) is introduced to
effectively bring the domains to the next generation Internet
scenario. The paper presents an architecture to address challenging
next generation Internet requirements such as node and domain
mobility, multi-homing, security, network composition and interdomain routing. Although our architecture supports all the
mentioned requirements, the focus of this paper is specifically on
node and domain mobility in order to evaluate and compare the
advantages of having DIDs for facilitating the mobility. First, we
present the generic Next Generation Internet architecture proposal
and its envisioned scenario. Then, we show how to instantiate it to
work together with the current Internet. We have developed a
prototype to evaluate our proposal and we depict results related to
node and domain mobility under this gradual deployment scenario
using the Internet as the core.
Gestão do Conhecimento e da Colaboração em
Pesquisa Clínica para Doenças Negligenciadas
Maria Beatriz Felgar de Toledo, Olga Fernada Nabuco de Araújo,
Marcos Rodrigues, MIRIAM AKEMI MANABE CAPRETZ, Marcelo
Fantinato, Itana Maria de Souza Gimenes, Rodrigo Bonacin,Ana
Cervigni Guerra, Tarcisio da Rocha, Mario Jino
In: Seminário Sobre Grandes Desafios da Computação no Brasil
Manaus Mar-2009 pp:1-6
Resumo: Uma em cada seis pessoas da população mundial sofre
com doenças negligenciadas. A pesquisa clínica é a fase mais
crítica no desenvolvimento de medicamentos. Seus passos devem
ser descritos de forma inequívoca e rigorosa por meio de
protocolos. Dois fatores que prejudicam a conclusão da pesquisa e
a liberação de medicamento seguro em tempo reduzido para a
população são: (a) falta de interesse dos grandes laboratórios
farmacêuticos - o alvo das drogas e vacinas para doenças
negligenciadas é a população menos favorecida e (b) inexistência
Sinopse da FEEC
de mecanismos de reconhecimento acadêmico para valorizar a
colaboração e compartilhamento de dados entre pesquisadores. A
gestão do conhecimento e da colaboração pode auxiliar a pesquisa
clínica: (a) otimizando a utilização de recursos, (b) propiciando
maior rapidez e eficiência no desenvolvimento da pesquisa, (c)
auxiliando o compartilhamento e reaproveitamento do
conhecimento pré-existente e (d) permitindo que vários atores
contribuam com recursos e conhecimento - pesquisadores, agentes
de saúde, população, governos, entidades filantrópicas,
laboratórios.
Palavras-chave: doenças negligenciadas, pesquisa clínica,
gestão do conhecimento, gestão da colaboração.
Performance Evaluation of Reactive and Proactive
Handover Schemes for IP Micromobility Networks
Thienne de Melo e Silva Mesquita Johnson, Rodrigo Chavez
Monteiro do Prado, Eduardo Nicola Ferraz Zagari, Tomás Antônio
Costa Badan, Eleri Cardozo, Lars Westberg
Abstract: Micromobility protocols aim to improve localized
mobility by reducing the handover overhead. The Mobility Plane
Architecture (MPA) was designed to support micromobility in
standard IP or MPLS/GMPLS networks in a network-centric way,
that is, the burden demanded by micromobility is placed on the
network, not on the mobile nodes. The aim of this paper is to
present the reactive and proactive handover procedures supported
by MPA, its modeling and performance evaluation. Results show
that the proactive handover loses much less packets than reactive
handover, being more suited for multimedia traffic.
Segmentation of DTI based on tensorial
morphological gradient
Letícia Rittner, Roberto de Alencar Lotufo
In: SPIE Medical Imaging 2009
Lake Buena Vista, USA Feb-2009 pp:1-12
Abstract: This paper presents a segmentation technique for
diffusion tensor imaging (DTI). This technique is based on a
tensorial morphological gradient (TMG), defined as the maximum
dissimilarity over the neighborhood. Once this gradient is
computed, the tensorial segmentation problem becomes an scalar
one, which can be solved by conventional techniques, such as
watershed transform and thresholding. Similarity functions,
namely the dot product, the tensorial dot product, the J-divergence
and the Frobenius norm, were compared, in order to understand
their differences regarding the measurement of tensor
dissimilarities. The study showed that the dot product and the
tensorial dot product turned out to be inappropriate for
computation of the TMG, while the Frobenius norm and the Jdivergence were both capable of measuring tensor dissimilarities,
despite the distortion of Frobenius norm, since it is not an affine
invariant measure. In order to validate the TMG as a solution for
DTI segmentation, its computation was performed using distinct
similarity measures and structuring elements. TMG results were
also compared to fractional anisotropy. Finally, synthetic and real
DTI were used in the method validation. Experiments showed that
the TMG enables the segmentation of DTI by watershed transform
or by a simple choice of a threshold. The strength of the proposed
segmentation method is its simplicity and robustness,
consequences of TMG computation. It enables the use, not only of
well-known algorithms and tools from the mathematical
morphology, but also of any other segmentation method to
segment DTI, since TMG computation transforms tensorial images
in scalar ones.
Keywords: Diffusion Tensor Imaging,
Segmentation,
Mathematical Morphology
Electrical Energy
A Predictive Control Approach for Long Term
Hydrothermal Scheduling
Monica de Souza Zambelli, Secundino Soares Filho
In: IEEE/PES Power Systems Conference & Exposition (PSCE)
Washington, EUA Mar-2009 pp:1-6
Abstract: This paper presents a predictive control approach for
long-term generation scheduling of hydro-thermal power systems.
The approach is based on an open-loop feedback control scheme
that uses a neural fuzzy network forecasting model, for handling
the stochastic nature of inflows, and a deterministic nonlinear
optimization model, to determine the discharge decisions to be
implemented. As a consequence, inflow correlations on time can
be represented by nonlinear relationships, and hydropower
generation and thermal fuel cost can be handled by nonlinear
functions, allowing a more precise modeling of the problem. A
simulation model was also developed for performance assessment
of the proposed approach. A comparison with the classical
stochastic dynamic programming approach, in the case of single
reservoir systems, revealed that the latter and the proposed
approach perform similarly. The approach was also applied to a
multi-reservoir system composed of 19 hydro plants and 10
reservoirs corresponding to a major cascade of the Brazilian power
system. The results show that the proposed approach performs as
well as in the single reservoir case study.
Keywords: fuzzy neural networks, hydrothermal scheduling,
optimization,
forecasting model,
stochastic dynamic
programming
An Aggregate Model Applied To The Short-Term
Bus Load Forecasting Problem
Ricardo Menezes Salgado, Rosangela Ballini, Takaaki Ohishi
In: IEEE/PES Power Systems Conference & Exposition (PSCE)
Washington, EUA Mar-2009 pp:1-8
Abstract: In this paper we present a methodology based on a
combination of clustering and forecasting techniques. The
proposed method is built in two phases: In the first phase, a
clustering algorithm is used to identify buses clusters with similar
daily load profile. In the second phase we introduce an aggregate
structure for to foresee each bus. The methodology was applied on
bus load data from the Brazilian North/Northeast system and the
results showed that the model was efficient with 2% to 4% average
percentage error level on the buses. The obtained forecasting was
compatible with the load safe operating levels of the Brazilian
power system.
Keywords: Short-Term Bus Load Forecasting, Forecasting
Model, Clustering Algorithm, Time Series Analysis.
Análise de Novos Sinais para a Detecção de
Ilhamento de Geradores Síncronos Distribuídos
Esloany Daisy Carniatto Delvecchi, Coutinho, D. F., Cunha, D. Q.
V., Diogo Salles Corrêa, José Carlos de Melo Vieira Jr, Walmir de
Freitas Filho
In: XI SEPOPE - Simpósio de Especialistas em Planejamento da
Operação e Expansão Elétrica, 2009
Belém, PA Mar-2009 pp:1-6
Resumo: Geradores síncronos conectados em redes de
distribuição de energia elétrica estão sujeitos a operar de forma
ilhada após a ocorrência de distúrbios na rede elétrica. Ilhamento
ocorre quando uma parte da rede de distribuição torna-se
eletricamente isolada da fonte de energia principal (subestação),
mas continua a ser energizada por geradores distribuídos
conectados no subsistema isolado. A prática atualmente utilizada
pelas concessionárias e recomendada nos principais guias técnicos
é desconectar todos os geradores tão logo ocorra um ilhamento.
Tipicamente, é necessário detectar uma situação de ilhamento em
menos de 2 segundos. Os métodos mais comuns e baratos para
detectar ilhamento compreendem relés baseados em medidas de
freqüência (sub/sobrefreqüência, taxa de variação de freqüência e
11
“salto de vetor”) e o relé de tensão. No entanto, esses relés podem
falhar se os níveis de desbalanço de potência ativa e reativa no
subsistema ilhado forem pequenos. Portanto, o objetivo deste
trabalho é investigar a potencialidade de um novo sinal para
detectar ilhamento de geradores síncronos distribuídos, como
forma de substituição ou complementação aos dispositivos de
proteção antiilhamento convencionais. O sinal analisado neste
trabalho se baseia na taxa de variação da potência ativa (dP/dt) do
gerador distribuído após a ocorrência do ilhamento. A investigação
é baseada no levantamento de um conjunto de curvas relacionando
tempo de detecção e desbalanço de potência ativa/reativa e no
conceito de desbalanço crítico de potência ativa/reativa. Tais
curvas são obtidas usando simulação dinâmica não-linear trifásica
considerando diferentes perfis de carga-geração na rede ilhada. Os
resultados obtidos mostram que o sinal analisado tem um grande
potencial para esse tipo de aplicação, porém é susceptível à
atuação indevida no caso da ocorrência de eventos que não sejam
ilhamentos. Assim, uma análise de falsa operação também é
conduzida e são propostas melhorias para minimizar e/ou eliminar
a atuação indevida de um relé baseado no sinal dP/dt.
Palavras-chave: Geração distribuída, detecção de ilhamento,
proteção de sistemas elétricos de potência.
Avaliação do Risco de Ocorrência de Ilhamentos
Não Intencionais de Geradores Síncronos
Distribuídos
Diogo Salles Corrêa, Paulo César Magalhães Meira, Ahda
Pionkoski Grilo Pavani, Walmir de Freitas Filho, Jose Carlos de
Melo Vieira Junior, Wiliun Xu
In: XI SEPOPE - Simpósio de Especialistas em Planejamento da
Operação e Expansão Elétrica, 2009
Resumo: Geradores síncronos conectados em redes de
distribuição de energia elétrica estão sujeitos a operarem de forma
ilhada após contingências como, por exemplo, curtos-circuitos.
Ilhamento ocorre quando uma parte da rede de distribuição opera
eletricamente isolada da subestação da concessionária, mas
continua a ser energizada por geradores distribuídos. Devido a um
conjunto de implicações técnicas e de segurança, a prática
atualmente utilizada pelas concessionárias e recomendada pelos
principais guias técnicos é desconectar todos os geradores da rede
isolada tão logo ocorra um ilhamento. Diversas técnicas
desenvolvidas para detectar ilhamentos de geradores distribuídos
estão disponíveis e a maioria delas possui limitações técnicas e são
propensas a falhar em determinadas situações. Neste contexto,
torna-se importante conhecer a probabilidade da ocorrência de
ilhamentos não intencionais em sistemas de distribuição e,
posteriormente, realizar uma avaliação dos riscos associados a tais
eventos. Esse conhecimento pode fornecer subsídios para que
medidas sejam tomadas no sentido de reduzir essa probabilidade
nas situações em que os riscos associados são mais elevados.
Portanto, neste trabalho apresenta-se uma ferramenta para estimar
e analisar o risco de ocorrência de ilhamentos de forma rápida e
confiável sem depender de numerosas e, por vezes, lentas
simulações de transitórios eletromagnéticos. Os geradores
analisados são máquinas síncronas e o sistema de proteção
antiilhamento é composto por relés baseados em medidas de
freqüência e/ou tensão, visto que atualmente estes são
considerados os dispositivos mais eficientes para realizar tal tarefa.
Como o desempenho desses relés está fortemente relacionado aos
desbalanços de potência ativa e reativa na rede ilhada, a idéia
básica da metodologia é desenvolver um índice baseado na
combinação desses desbalanços e da curva diária de carga do
alimentador. Os índices de risco de ilhamento foram obtidos
através do método proposto para uma típica rede de distribuição, e,
posteriormente, os resultados foram validados por meio de
simulações dinâmicas do tipo de transitórios eletromagnéticos.
Ressalta-se que os principais fatores que afetam o desempenho do
sistema de proteção antiilhamento podem ser prontamente
determinados com a aplicação das metodologias desenvolvidas. Os
12
resultados obtidos mostraram-se precisos quando comparados aos
obtidos por meio de repetidas simulações do tipo de transitórios
eletromagnéticos. A metodologia e os resultados obtidos permitem
avaliar se a probabilidade da ocorrência do ilhamento em
instalações existentes justifica o investimento em melhorias
técnicas ou se a alteração de procedimentos operativos é suficiente
para minimizar e até mesmo eliminar a possibilidade da ocorrência
do evento em determinados períodos de tempo.
Palavras-chave: Ilhamento, geração distribuída, proteção de
sistemas de energia elétrica, máquina síncrona.
Control Strategy for Battery-Ultracapacitor Hybrid
Energy Storage System
Fellipe Saldanha Garcia, André Augusto Ferreira, José Antenor
Pomilio
In: 24tn IEEE Applied Power Electronics Conference – APEC ISBN: 978-1-4244-2811-3
Washington, USA Feb-2009 pp:826-832 doi:
10.1109/APEC.2009.4802757
Abstract: Hybrid energy storage systems have been investigated
with the objective of improving the storage of electrical energy. In
these systems, two (or more) energy sources work together to
create a superior device in comparison with a single source. In
particular, batteries and ultracapacitors have complementary
characteristics that make them attractive for a hybrid energy
storage system. But the result of this combination is fundamentally
related to how the sources are interconnect and controlled. The
present work reviews the advantages of batteryultracapacitor
hybridization, some existing solutions to coordinate the power
flow, and proposes a new control strategy, designed for the
improvement of performance and energy efficiency, while also
extending the battery life. The control strategy uses classical
controllers and provides good results with low computational cost.
Experimental results are presented.
Keywords: Control systems; Power electronics; Road vehicle
electric propulsion; Ultracapacitor.
Management and Analysis of Data from
Hydroelectric Plan
Ieda Geriberto Hidalgo, Secundino Soares Filho, Darrel G.
Fontane, Marcelo Augusto Cicogna
In: IEEE PES Power Systems Conference & Exhibition (PSCE)
Seattle Mar-2009 pp:1-6
Abstract: This paper presents a computer aided system that aims
to improve the quality of data for hydroelectric plants. This system
consists of two modules. The first is a relational database that
organizes, standardizes and manages data from hydroelectric
plants. The second module allows a user to build, store and
manage advanced queries on this or certain other databases. The
data manager and the queries builder were tested with data from
Brazilian hydroelectric plants and the results show the potential for
a significant improvement in terms of efficiency for the operation
planning of electrical power systems. Planning has strong
dependence on the quality of the data used in mathematical models
and other built-in computational tools. The software project and
the computational implementation of these modules use the
Object-Oriented Paradigm, the C++ Programming Language and
the Structured Query Language (SQL). This assures a modern and
efficient structure for the system.
Keywords: Computer Aided Analysis,
Data Management
System, Data Query, Data Searching, Electrical Engineering,
Objected-Oriented Programming, Power Generation Planning,
Programming Language, Relational Database.
Nova metodologia de resolução de fluxo de
potência com representação de controles e limites
via técnicas de programação não linear
Adriana Scheffer Quintela Ferreira, Carlos Alberto de Castro Jr.
In: XI Simpósio de Especialistas em Planejamento da Operação e
Expansão Elétrica - Sepope
Sinopse da FEEC
Resumo: A representação e análise adequadas dos controles e o
tratamento de limites visam aproximar a solução obtida pelo fluxo
de potência do ponto de operação real. Em princípio, a interação
dos controles representa os efeitos dos acoplamentos dos
dispositivos de controle na solução. A eficiência da solução do
fluxo de potência pode ser bastante afetada pelas interações
existentes entre os controles. Situações em que há conflito entre as
atuações dos controles podem resultar em convergência lenta e
freqüentemente provocar soluções oscilatórias e até mesmo a
divergência. Este trabalho apresenta o estudo e a implementação
de um programa computacional para o cálculo de fluxo de
potência, em que a atuação e verificação de limites dos
equipamentos de controle são considerados através da utilização
de técnicas de programação não linear. A consideração dos
controles e limites é feita através da técnica de ajustes alternados,
podendo ser facilmente incorporada a programas computacionais
de fluxo de potência já existentes, baseados no método de Newton
e desacoplados. A inovação consiste em atualizar as variáveis de
controle através de um problema de otimização que considera as
interações (e eventuais conflitos) existentes entre os controles, pois
é levada em conta a contribuição dos controles que afetam a
variável a ser controlada. Desta maneira as estratégias de controle
são consideradas a cada iteração do fluxo de potência, mantendo
os limites operacionais dos componentes do sistema elétrico. Após
a convergência do fluxo de potência, ter-se-á o estado operacional
do sistema elétrico cujo ponto de equilíbrio seja factível e o mais
próximo possível do ponto de operação real. A trajetória da
solução a cada iteração do fluxo de potência, a interação entre os
controles bem como o comportamento destes e o atendimento aos
limites da geração de potência reativa das barras de geração com
tensão controlada são observados durante as simulações realizadas.
O potencial de utilização do processo no ambiente de operação de
redes em tempo real é avaliado. Os resultados obtidos com
sistemas reais de grande porte demonstram que a metodologia
proposta é robusta e eficaz. O tempo computacional de
processamento do algoritmo é pequeno, indicando o potencial de
utilização da metodologia proposta em tempo real, mesmo em
cenários de contingências e situações de carga pesada. O algoritmo
desenvolvido constitui uma ferramenta importante para auxiliar a
operação e o planejamento da operação dos sistemas de potência.
Palavras-chave: Operação de sistemas interligados; operação
em tempo real; interações entre controles; programação não
linear; ajustes alternados; fluxo de carga convencional; método
de Newton; métodos desacoplados
Proposition of a Half-Wave Length Energization
Case Test
Maria Cristina Dias Tavares, Carlos Medeiros Portela
In: IPST/09 International Conference on Power Sistems Transients
Kyoto, Japão Jan-2009 pp:1-6
Abstract: In Brazil big blocks of energy will be transported
through distances between 2500 and 3000 km to strong network
nodes. Among the AC transmission systems alternatives being
analyzed the half-wave length transmission seems to be the natural
solution as the lengths involved are around a half-wave length of a
60 Hz frequency system, as the Brazilian one. As there is no halfwave transmission system in operation in the world, there is a
major sense of caution in order to be the first to construct and use
this new AC-link. In order to give some support a field test with a
set of existing similar 500 kV lines that could be connected in
series was proposed to simulate the AC-link behavior under some
controlled switching. The main results of the proposed AC-link
test simulated in PSCAD/EMTDC and ATP are presented.
Keywords: Very long transmission systems, Half-wave length,
electromagnetic transients, life-test.
Simple Method for Computing Power Systems
Maximum Loading Conditions
Resumo: A very simple and fast method for computing power
systems maximum loading points is proposed in this paper. These
points are simply computed through repeated load flow solutions.
The main contribution resides in the appropriate use of a special
load flow with step size optimization and the extraction of useful
information from it, which guides the search for the desired
maximum loading point. The simplicity and robustness of the
proposed method are verified through simulations involving test
and realistic systems.
Palavras-chave: Load flow analysis; Voltage control; voltage
stability.
A Semi-Blind Concurrent Algorithm with Scattered
Pilot Tones for OFDM Equalization
Estevan Lopes, Fabbryccio Akkazzha Chaves M .Cardoso, Sandro
Adriano Fasolo, Dalton Soares Arantes
In: International Workshop on Telecommunications - IWT 2009 ISBN: 18067662
São Paulo, SP Feb-2009 pp:1-6
Abstract: This paper presents a concurrent algorithm with semiblind frequency-domain equalization (post FFT) in OFDM
systems. The objective is to allow the OFDM system design with
increased data throughput and without performance loss, when
compared with pilot tone based on conventional channel
estimation techniques. This work exploits the concurrent
equalization concept of the CMA+SDD to develop an efficient
post-FFT bank of equalizers. The algorithm can be considered
semi-blind because it uses channel information, obtained from
scattered pilot tones, to initialize and to supervise the bank of
equalizers when pilots are present, otherwise remaining blind
during the equalization process. In order to support such
concurrent equalization, the system should provide scattered pilot
tones only in the first symbol of each OFDM super-frame,
allowing algorithm initialization when the receiver is turned on. In
the remaining super-frame symbols, scattered pilot tones are
suppressed to increase the overall system throughput.
Keywords: Concurrent Algorithm, OFDM Systems, Semi-Blind
Equalization, Soft Decision-Directed.
Estevan Marcelo Lopes, Dalton S. Arantes, Fabbryccio A. C. M.
Cardoso and Sandro Adriano Fasolo
6182114243 São Paulo Brasil Feb-2009 pp:145 Abstract: This paper presents a concurrent algorithm with semiblind frequency-domain equalization (post FFT) in OFDM
Cássio Hideki Fujisawa, Carlos Alberto de Castro Jr.
In: Power Systems Conference & Exposition - PSCE
Seattle, USA Mar-2009 pp:1-6
13
Keywords: Loss Probability, Multifractal Processes, Network
Traffic.
Estevan Marcelo Lopes, Dalton S. Arantes, Fabbryccio A. C. M.
Cardoso and Sandro Adriano Fasolo
6182114243 São Paulo Brasil Feb-2009 pp:145 Abstract: This paper presents a concurrent algorithm with semiblind frequency-domain equalization (post FFT) in OFDM
An approach for evaluation the buffer queueing
behavior of multifractal network traffic Flows
An adaptive RLE encoder to compress
electrocardiograms
André Filgueiras de Araujo, Yuzo Iano
In: IWT 2009 - International Workshop on Telecommunications ISBN: ISSN: 1806-7662
Abstract: Motion estimation is a critical stage in video
compression schemes. It impacts greatly on system performance
by minimizing the energy of the residual frame to be transmitted.
As usual video compression standards (such as MPEG-x and
H.26x) do not specify a particular technique to use, it seems
important to study the recent developments in the area aiming to
consider them comparatively. The focus of this work is on the
trade-offs of three state-of-the-art block-based techniques: the
Adaptive Modified Two-Bit Transform (AM2BT), the Adaptive
Multilevel Successive Elimination Algorithm (AdaMSEA) and the
Enhanced Adaptive Rood Pattern Search (E-ARPS). The principal
measures to be taken into account in these analyses are the PSNR,
the MSSIM and the computational complexity.
Keywords: AM2BT, AdaMSEA, block-matching algorithms, EARPS, motion estimation, video coding.
Cristiano Marcos Agulhari, Ivanil Sebastião Bonatti, Pedro Luis
Dias Peres
São Paulo Feb-2009 pp:1-6
Abstract: A compression method, based on the choice of a
wavelet that matches to the electrocardiogram to be compressed, is
proposed in this paper. The scaling filter that minimizes the
distortion of the compressed signal is used on the determination of
the wavelet, being retained only the most significant coefficients
of projection of the signal on the wavelet subspaces. The threshold
for the selection of the most significant coefficients is obtained in
order to satisfy a pre-specified distortion measure. The significant
coefficients and the bitmaps of location in each wavelet subspace
are encoded by applying the Run Length Encoding technique using
codewords whose length are adapted for each subspace. Several
tests with electrocardiograms from the MIT-BIH database
illustrate the efficiency of the method.
Keywords: Data compression,
electrocardiogram signals,
ECG, run length encoding, wavelet.
An Approach for Evaluating the Buffer Queueing
Behavior of Multifractal Network Traffic Flows.
Jeferson Wilian de Godoy Stênico, Flávio Henrique Teles Vieira
and Lee Luan Ling
In: IWT/09 - An Approach for Evaluating the Buffer Queueing
Behavior of Multifractal Network Traffic Flows.
Feb-2009
Abstract: In this paper, we propose an analytical expression for
calculating the byte loss probability for multifractal traffic arrivals
at a single server queue. Initially, we address the theory
concerning the multifractal processes, especially the Hölder
exponents of the multifractal traffic traces. Next, we focus on the
second order statistics for the multifractal processes. More
specifically, we assume that an exponential model is adequate for
representing the variance versus time scale aggregation. Finally,
we evaluate the performance of the proposed approach by
estimating the theorectical byte loss probability against the results
obtained by simulations with real traffic traces and that through a
method based only on monofractal characteristics.
14
Jeferson Wiliam de Godoy Stenico, Flavio Henrique Teles Vieira,
Lee Luan Ling
São Paulo Feb-2009 pp:1-8
Abstract: In this paper, we propose an analytical expression for
calculating the byte loss probability for multifractal traffic arrivals
at a single server queue. Initially, we address the theory
concerning the multifractal processes, especially the Hölder
exponents of the multifractal traffic traces. Next, we focus on the
second order statistics for the multifractal processes. More
specifically, we assume that an exponential model is adequate for
representing the variance versus time scale aggregation. Finally,
we evaluate the performance of the proposed approach by
estimating the theorectical byte loss probability against the results
obtained by simulations with real traffic traces and that through a
method based only on monofractal characteristics.
Keywords: Loss Probability, Multifractal Processes, Network
Traffic.
Comparative Analysis of State-of-the-art Blockbased Motion Estimation Techniques
Maximal-Ratio and Equal-Gain combining in Hoyt
(Nakagami-q) Fading
Rausley Adriano Amaral de Souza, Michel Daoud Yacoub
In: IEEE Vehicular Technology Conference
Barcelona, Espanha Apr-2009 pp:1-5
Abstract: New, exact expressions for the bivariate Hoyt
(Nakagami-q) processes in a nonstationary environment are
derived. More specifically, the following are obtained: joint
probability density function and joint cumulative distribution
function. In addition the outage probability for the Maximal- Ratio
and Equal-Gain Combining techniques in a correlated Hoyt
channel are obtained. The expressions are mathematically tractable
and flexible enough to accommodate a myriad of correlation
scenarios, useful in the analysis of a more general fading
environment.
Keywords: Nakagami-q (Hoyt),
Bivariate Distribution,
Correlation, Combiner.
On Performance of WH-STC-OFDM and WH-SFCOFDM in Non-Linear Time Variant Channels
Luciano Leonel Mendes, Renato Baldini Filho
São Paulo Jan-2009 pp:129-134
Sinopse da FEEC
Abstract: Orthogonal Frequency Division Multiplexing is being
widely used on today’s digital communication standards, mainly
because its robustness against multipath channels. Although, the
high PAPR of the OFDM signal becomes a problem when a
mobile communication takes place, because of the power
limitation of the mobile unit. One technique that can be used to
reduce the PAPR of OFDM signals is to apply the WalshHadamard Transform on the data prior the IFFT. The aim of this
paper is to analyze the performance of this system, considering the
use of space-time and space-frequency diversity in a time variant
multipath channel.
Keywords: OFDM, PAPR, multipath channels
Performance Evaluation of Fundamental Frequency
Estimation Algorithms
Tiago Fernandes Tavares, Jayme Garcia Arnal Barbedo and
Amauri Lopes
São Paulo Feb-2009 pp:94 - 97
Abstract: A method for evaluation of the performance of
fundamental frequency estimation algorithms is proposed. The
method determines the minimum signal-to-noise ratio (SNR)
necessary for given frequency estimation algorithm to work
properly and also provides the accuracy of the estimates.
Therefore, the proposed method allows one to determine if a given
frequency estimation algorithm is adequated for a specific
application, taking into account the available SNR and the
precision requirements.
Keywords: Terms—digital signal processing, fundamental
frequency, performance evaluation
Performance of QS-CDMA Ad Hoc Networks using
ZCZ Spreading Sequences
Tarciana Araujo Lopes, Márzio Geandre da Silva Rego, Renato
Baldini Filho
São Paulo Jan-2009 pp:152-155
Abstract: This work investigates the performance of zero
correlation zone (ZCZ) codes in quasi-synchronous CDMA ad hoc
networks on multipath fading channels. One of the main defiances
of CDMA ad hoc networks is to eliminate the near-far effects. This
limitation can be minimized by using ZCZ codes that mitigate the
effects of the intersymbol and multiple access interference in
multipath channels. The performance analysis is based on the
evaluation the expected progress per hop.
Keywords: ad hoc networks, quasi-synchronous CDMA, ZCZ
codes.
Performance of QS-CDMA Ad Hoc Networks using
ZCZ Spreading Sequences
Tarciana Araujo Lopes, Márzio Geandre da Silva Rego, Renato
Baldini Filho
Abstract: This work investigates the performance of zero
correlation zone (ZCZ) codes in quasi-synchronous CDMA ad hoc
networks on multipath fading channels. One of the main defiances
of CDMA ad hoc networks is to eliminate the near-far effects. A
possible solution to this limitation is to use these codes that are
able to mitigate the effects of the intersymbol and multiple access
interference in multipath channels, due to their correlation
characteristics. The analysis is based on the evaluation the
expected progress per hop, an ad hoc networks performance
measure.
Keywords: ad hoc networks, quasi-synchronous CDMA, ZCZ
codes.
QVoip – A tool to evaluate the quality of VoIP calls
using E-model
Fabio Pessoa Nunes, Fabio Sakuray, Leonardo de Souza Mendes
and Mario Lemes Proença Jr.
São Paulo - Brasil Feb-2009 pp:25-29
Abstract: The VoIP systems are very sensitive to some
parameters that can change according to the utilization of the
network where they pass. The tool QVoip is capable of making
VoIP calls and measuring voice quality. This measurement is
made with the utilization of E-model using factors from the VoIP
application and variables from the network to evaluate quality.
With this tool it is possible to analyze the factors that degrade the
voice and help designers to evaluate if a network is good for
VOIP.
Keywords: E-model, QoS, VoIP
Source and Channel Coding with Unequal Error
Protection for Image Transmission in AWGN
Channel
Ricardo Barroso Leite, Yuzo Iano, Ana Lúcia Mendes Cruz,
Fernando Silvestre da Silva
Abstract: Current competition of digital television standards, 3G
mobile communications, satellite data transmission and the mobile
devices high capacity have promoted a recent boost in Channel
Coding Forward Error Correction and in Source Coding. However,
the performance deeply affected by the additive errors incidence
position remains as a constant issue. In order to avoid this
problem, non-uniform schemes of channel coding have been
proposed in the literature, named Unequal Error Protection (UEP).
Concerning this matter, this paper presents different new UEP
encoding schemes combining DWT/SPIHT source coding and the
Convolutional Parallel Turbo Coding. The results shown that this
technique can significantly improve the reconstructed image
quality for noisy channels when compared to the traditional EEP
system. This result can be very useful for low power or high noise
applications such as satellite communications and mobile
transmission.
Keywords: Channel Coding, Image Compression, Source
Coding, UEP
The Forward Link Performance Study of the WiMAX
System Under Different Schedulers
Leandro Bento Sena Marques e Shusaburo Motoyama
Abstract: The forward link performance study of the WiMAX
system is presented in this paper. The study is carried out using
HTTP traffic model and several different schedulers. The average
packet delay, the throughput and packet loss percentage are
analyzed through simulation in function of traffic load. The
schedulers adopted in this study are Max C/I (Maximum Carrier
Interference), PF (Proportional Fair) and Pr/PF (Priority
Proportional Fair). The results show that standardized IEEE
802.16e system allows data transmission at high bits rates.
Moreover, it was showed that depending on the chosen scheduler,
it is possible to assure the QoS for users with high and low priority
in WiMAX system.
Keywords: WiMAX System and schedulers PF, Max C/I, Pr/PF
Vertical Handoff Algorithms with QoS Guarantee
for 4G Networks
Leandro Bento Sena Marques, Shusaburo Motoyama
In: IEEE Latin-American Conference on Communications
(LatinCom)
15
Medellin, Colômbia Jan-2009 pp:1-6
Abstract: One of main challenges of fourth generation wireless
networks (4G) will be the integration of various mobile
technologies such as CDMA 1xEV-DO RA, UMTS/HSDPA and
WiMAX. In this paper is investigated the interoperability between
the CDMA 1xEV-DO RA and the UMTS/HSDPA in the 4G
context. New algorithms for vertical handoff traffic acceptance are
proposed considering the link occupation, the buffer occupation
and the radio signal strength (RSS). Different algorithms are
evaluated through QoS metrics such as the average packet delay,
the throughput and the loss percentage in function of vertical
handoff traffic load. The results showed that depending on the
chosen algorithm it is possible to assure the QoS of 1xEV-DO RA
and UMTS/HSDPA systems and still to accept a good amount of
vertical handoff traffic.
Keywords: 1xEV-DO RA system,
UMTS/HSDPA system,
algorithms for vertical handoff traffic acceptance.
Book
Independent Component Analysis and Signal
Separation
Tulay Adali, Christian Jutten, João Marcos Travassos Romano,
Allan Kardec Barros
Serie: 1
Springer New York, EUA v:1 Mar-2009 pp:785
Abstract: This book constitutes the refereed proceedings of the
8th International Conference on Independent Component Analysis
and Signal Separation, ICA 2009, held in Paraty, Brazil, in March
2009. The 97 revised papers presented were carefully reviewed
and selected from 137 submissions. The papers are organized in
topical sections on theory, algorithms and architectures,
biomedical applications, image processing, speech and audio
processing, other applications, as well as a special session on
evaluation
11 - An Analysis of Unsupervised Signal
Processing Methods in the Context of Correlated
Sources
Aline Neves, Cristina Wada, Ricardo Suyama, Romis Ribeiro de
Faissol Attux, João Marcos Travassos Romano
In: Independent Component Analysis and Signal Separation Ed.:1 - Adali, T.; Jutten, C.; Romano, J.M.T.; Barros, A.K.(Ed.) - ISBN:
978-3-642-00598-5
Serie: Lecture Notes in Computer Science
Springer Heidelberg v:5441 Mar-2009 pp:82-89 doi:
10.1007/978-3-642-00599-2_11
Abstract: In light of the recently proposed generalized
correlation function named correntropy, which exploits higherorder statistics and the time structure of signals, we have, in this
work, two main objectives: 1) to give a new interpretation –
founded on the relationships between the constant modulus (CM)
and Shalvi-Weinstein criteria and between the latter and methods
for ICA based on nongaussianity – to the performance of the
constant modulus approach under dependent sources and 2) to
analyze the correntropy in the context of blind deconvolution of
i.i.d. and dependent sources, as well as to establish elements of a
comparison between it and the CMA. The analyses and simulation
results unveil some theoretical aspects hitherto unexplored.
Keywords: Blind deconvolution - correntropy - constant
modulus criterion - Shalvi-Weinstein criteria - nongaussianitybased ICA
75 - An ICA-Based Method for Blind Source
Separation in Sparse Domains
Everton Zaccaria Nadalin, Ricardo Suyama, Romis Ribeiro de
Faissol Attux
In: Independent Component Analysis and Signal Separation Ed.:1 - Tülay Adali, Christian Jutten, João Marcos Travassos Romano,
Allan Kardec Barros(Ed.) - ISBN: 978-3-642-00598-5
10.1007/978-3-642-00599-2_75
Book Chapter
Automation
1 - An ICA-Based Method for Blind Source
Separation in Sparse Domains
Everton Zaccaria Nadalin, Ricardo Suyama, Romis Ribeiro de
Faissol Attux
In: Independent Component Analysis and Signal Separation -Tulay Adali, Christian Jutten, Joao Marcos Travassos Romano,
Allan Kardec Barros(Ed.) - ISBN: 978-3-642005985
Springer Heidelberg, Alemanha v:5441 Mar-2009 pp:597-604
Abstract: In this work, we propose and analyze a method to solve
the problem of underdetermined blind source separation (and
identification) that employs the ideas of sparse component analysis
(SCA) and independent component analysis (ICA). The main
rationale of the approach is to allow the possibility of reaching a
method that is more robust with respect to the degree of sparseness
of the involved signals and more effective in the use of
information brought by multiple sensors. The ICA-based solution
is tested with the aid of three representative scenarios and its
performance is compared with that of one of the soundest SCA
techniques available, the DEMIXN algorithm.
Keywords: Sparse component analysis - independent component
analysis -blind identification - audio signal processing
16
Abstract: In this work, we propose and analyze a method to solve
the problem of underdetermined blind source separation (and
identification) that employs the ideas of sparse component analysis
(SCA) and independent component analysis (ICA). The main
rationale of the approach is to allow the possibility of reaching a
method that is more robust with respect to the degree of sparseness
of the involved signals and more effective in the use of
information brought by multiple sensors. The ICA-based solution
is tested with the aid of three representative scenarios and its
performance is compared with that of one of the soundest SCA
techniques available, the DEMIXN algorithm.
Keywords: Sparse component analysis - independent component
analysis - blind identification - audio signal processing
16 - Blind Extraction of Chaotic Sources from
Gaussian White Noise Based on a Measure of
Determinism
Diogo Coutinho Soriano, Ricardo Suyama, Romis Ribeiro de
Faissol Attux
978-3-642-00598-5
10.1007/978-3-642-00599-2_16
Abstract: This work presents a new method to perform blind
extraction of chaotic signals mixed with stochastic sources. The
technique makes use of the features underlying the generation of
chaotic sources to recover a signal that is “as deterministic as
possible”. The method is applied to invertible and
underdertemined mixture models and illustrates the potential of
Sinopse da FEEC
incorporating such a priori information about the nature of the
sources in the process of blind extraction.
Keywords: Blind source extraction - blind source separation chaotic signals - recurrence maps
spatio-temporal behavior is properly reproduced. One and twodimensional regular lattices will be considered and a distinct set of
transition rules must be defined in each application scenario.
Given that the number of rules equals the number of cells in the
lattice, the search space is very large and evolutionary algorithms
are considered to optimize the set of transition rules: a genetic
algorithm for the one-dimensional and binary-state case, and an
evolution strategy for the two-dimensional and multivalued-state
case. The empirical results indicate that the increment in flexibility
provided by the existence of a distinct rule for each cell in the
lattice opens the possibility of producing more effective spatiotemporal models. In the two-dimensional lattice, the global
dynamic of the cellular automata can be properly manipulated to
find a configuration that will promote convergence to a desired
equilibrium state, starting from an arbitrary initial state and
possibly obeying some restrictive conditions for the intermediary
states of the cells in the lattice.
Keywords: Non-uniform cellular automata, spatio-temporal
modeling, evolutionary computation, one and two-dimensional
lattices
30 - Blind Source Separation of Post-Nonlinear
Mixtures Using Evolutionary Computation and
Gaussianization
Tiago Macedo Dias, Romis Ribeiro de Faissol Attux, João Marcos
Travassos Romano, Ricardo Suyama
978-3-642-00598-5
10.1007/978-3-642-00599-2_30
Abstract: In this work, we propose a new method for source
separation of post-nonlinear mixtures that combines evolutionarybased global search, gaussianization and a local search step based
on FastICA algorithm. The rationale of the proposal is to attempt
to obtain efficient and precise solutions using with parsimony the
available computational resources, and, as shown by the
simulation results, this aim was satisfactorily fulfilled.
Keywords: Nonlinear blind source separation - post-nonlinear
models - gaussianization - evolutionary algorithms - artificial
immune systems
47 - Nonlinear Blind Source Deconvolution Using
Recurrent Prediction-Error Filters and an Artificial
Immune System
Cristina Wada, Rafael Ferrari, Ricardo Suyama, Romis Ribeiro de
Faissol Attux, Fernando Jose Von Zuben
In: Independent Component Analysis and Signal Separation Ed.:1 - Tülay Adali, Christian Jutten, João Marcos Travassos Romano,
10.1007/978-3-642-00599-2_47
Abstract: In this work, we propose a general framework for
nonlinear prediction-based blind source deconvolution that
employs recurrent structures (multi-layer perceptrons and an echo
state network) and an immune-inspired optimization tool. The
paradigm is tested under different channel models and, in all cases,
the presence of feedback loops is shown to be a relevant factor in
terms of performance. These results open interesting perspectives
for dealing with classical problems such as equalization and blind
source separation.
Keywords: Unsupervised Deconvolution - Nonlinear Prediction
- Recurrent Neural Networks - Echo State Networks - Artificial
Immune Systems
1 - Synthesis of Spatio-temporal Models by the
Evolution of Non-uniform Cellular Automata
Ana Lúcia Travassos Romano, Wilfredo Jaime Puma Villanueva,
Marcelo Serrano Zanetti, Fernando José Von Zuben
In: Foundations of Computational Intelligence -- A. Abraham et
al.(Ed.) - ISBN: 978-3-642010873
Serie: Studies in Computational Intelligence
SpringerLink Berlin, Alemanha v:4 Apr-2009 pp:85-104 doi:
10.1007/978-3-642-01088-0_4
Abstract: The reproduction of arbitrary spatio-temporal behavior
by means of mathematical models is necessary in several research
fields. These mathematical models may help to understand the
phenomena and can be used to make predictions and to validate
new hypotheses. Here, the mathematical modeling will be
achieved by means of the search for cellular automata – group of
cells distributed in a regular lattice and having a state to be
updated along time – with a distinct transition rule associated with
each cell, denoted non-uniform cellular automata. The aim is to
determine one rule for each cell in the lattice so that the desired
3 - On the Relationships between MMSE and
Information-Theoretic-Based Blind Criterion for
Minimum BER Filtering
Charles Casimiro Cavalcante, João Marcos Travassos Romano
In: Independent Component Analysis and Signal Separation -Tülay Adali, Christian Jutten, João Marcos Travassos Romano,
Springer Berlin / Heidelberg Berlin v:5441 Mar-2009 pp:17-24
doi: 10.1007/978-3-642-00599-2_3
Abstract: In this paper we present a relationship between
supervised (MMSE) and unsupervised criteria for minimum bit
error rate (BER) filtering. A criterion based on the probability
density function (pdf) estimation which has an information
theoretical approach is used to link the MMSE criterion and the
maximum a posteriori one in order to obtain a linear filter that
minimizes the BER. An analytical relationship among those three
criteria is presented and analyzed showing the limits imposed to
achieve minimum BER without training sequences when the pdf
estimation-based criterion is considered
Keywords: Adaptive Filtering, Channel Equalization, Minimum
Bit-Error Rate Filtering
Event Organization
8th International Conference on Independent
Component Analysis and Signal Separation, ICA
2009
Tülay Adali, Christian Jutten, Allan Kardec Barros,João Marcos T.
Romano
FEEC-Unicamp Paraty - RJ Mar-2009
Abstract: Independent Component Analysis and Signal
Separation is one of the most exciting current areas of research in
statistical signal processing and unsupervised machine learning.
The area has received attention from several research communities
including those of machine learning, neural networks, statistical
signal processing and Bayesian modeling. Independent Component
Analysis and Signal Separation has applications at the intersection
of many science and engineering disciplines concerned with
understanding and extracting useful information from data as
diverse as neuronal activity and brain images, bioinformatics,
communications, the world wide web, audio, video, sensor signals,
or time series.
This year, the 8th International Conference on Independent
Component Analysis and Signal Separation, ICA 2009, was held
17
in Paraty, Brazil. The meeting feature keynote addresses by
leading researchers, as well as invited and contributed papers. ICA
2009 also feature a special session on the first community-based
Signal Separation Evaluation Campaign
Anais do II EADCA - Encontro de Alunos e
Docentes do DCA
Wu Shin Ting, Romis Ribeiro de Faissol Attux
DCA-FEEC-Unicamp Campinas, SP Mar-2009
Resumo: Os objetivos deste encontro são, essencialmente, dar
aos alunos de pós-graduação do DCA-FEEC a oportunidade de
apresentarem seus trabalhos de pesquisa e promover a interação
científica e o livre debate de idéias entre eles e os docentes do
departamento. Evocando assim o nobre espírito de cooperação
científica. Os trabalhos de pesquisa em desenvolvimento no DCAFEEC são publicamente apresentados e divulgados em CD.
Electrical Energy
SISPOT'2009 - Encontro Interno de Pesquisadores
em Sistemas de Potência, realizado na FEEC /
UNICAMP
Carlos Alberto de Castro Jr, Walmir de Freitas Filho, Luiz Carlos
Pereira da Silva
Campinas Abr-2009
Resumo: O Encontro de Pesquisadores em Sistemas de Potência
é um evento anual da Faculdade de Engenharia Elétrica e de
Computação (FEEC) da UNICAMP. São apresentados os
trabalhos de pesquisa em andamento ou recentemente concluídos
na FEEC na área de sistemas elétricos de potência. Os trabalhos
são apresentados por professores e alunos de pós-graduação e
graduação.
Patents
Método para excitação de lasers a gás por meio de
descarga tipo theta-pinch.
César José Bonjuani Pagan, Graziela Noeli Wakamatu, Ioshiaki
Doi
Abr-2009
Resumo: Utilização da descarga tipo theta-pinch para excitar o
meio ativo e causar a emissão de radiação laser. Para este efeito é
montada uma cavidade ressonante tipo fabri-perot composta de
dois espelhos frontalmente instalados e alinhados de tal forma que
a região onde deve ficar o meio ativo seja situada no interior do
solenóide de theta-pinch.
Processos de obtenção de dispositivos eletrônicos
a base de nanoeletrodos e dispositivos eletrônicos
obtidos a partir dos mesmos
Lauro Tatsuo Kubota, Alexandre Kisner, José Alexandre Diniz,
Fábio Aparecido Cavarsan
Mar-2009
Resumo: A presente invenção refere-se a um processo de
desenvolvimento de obtenção de um conjunto de dispositivos
eletrônicos, os quais podem ser configurados para detectar
espécies de natureza química e/ou biológicas. Mais
especificamente, referidos dispositivos eletrônicos compreendem
sensores do tipo transistores de efeito de campo sensíveis a íons
(ISFETs), nos quais por meio de deposição química foram
implementados nanocristais de ouro (Au) e prata (Ag) para
formação de nanoeletrodos de porta de um conjunto de ISFETs
ligados em paralelo.
18
Master's dissertations
Automation
STABILITY FRONTIERS ANALYSIS OF THE
SYNCHRONOUS MACHINES UNDER THE THIRD
ORDER MODEL
Análise das fronteiras de estabilidade da máquina
síncrona vista pelo modelo de 3ª ordem.
Heverton Augusto Pereira
Supervisor: Ana Cristina Cavalcanti Lyra (DMCSI)
Defense date: Feb,09 2009
Abstract: The ways to spread knowledge in the last decades have
been rapidly evolved, most due to improvements on information
technology. The modeling of physical systems has reached vast
complexity. In advance, the mathematical equations used on these
models have become harder to interpret. This complexity imposes
a challenge on teaching synchronous machines and it can be
managed through the use of computational resources. The purpose
of this work is to develop a didactical application, that helps
teaching synchronous machines stability and allow the analysis of
the reactive control and stabilizing signal influences on
synchronous machine stability. Additionally, the influence of the
transformer reactance on the stability is analyzed. Every stability
analysis included on this work has as premise the stability
frontiers, oscillatory and aperiodic, developed through the
synchronous machine's third order model. The 3rd order model
was developed from the 5th order and none of the models include
dampers winding. A comparison between the 3rd and 5th order
models showed great similarity among them. Matlab(r) was used
to develop a graphical interface and the models were simulated
with the use of Simulink(r). Usability was the key factor during the
development of the interface, were the simulations can be done
without the need of low-level languages. Thus, the focus should be
analyzing the graphics generated through the simulation. The five
modules developed were: 3rd order model simulation, comparison
between 3rd and 5th order models, reactive gain comparison,
stability signal comparisons and the comparison with and without
transformer. New modules can be easily added to this work,
providing new updates without affecting the original system
Keywords: Synchronous machines, Simulation, Stability
frontiers
REDISTRICTING CAPACITATED PROBLEM
Problema de reagrupamento capacitado.
Laura Silva de Assis
Supervisor: Paulo Morelato França (DENSIS)
Defense date: Mar,27 2009
Abstract: The aim of this dissertation is to develop an eficient
methodology to solve the multicriteria redistricting capacitated
problem (PACM), in which objects with associated weights are
given, which must be partitioned into groups with limited capacity.
In this work, the PACM is inserted in to a reassignment problem of
urban clusters of clients, in which the readings of the eletric energy
measurement must be performed by the company of energy
distribution. The reading operation is performed over lots
geographically defined is performed once a month by the readers.
The motivation of this work is due to the fact that the size and
shape of the lots become obsolete after some time, due to
modifications introduced in the current conformation, desarranging
the balance between the lots and outdating the routes. For this
reason it is important to achieve a reassignment of the lots trying
to decrease the operational costs of reading, as well as minimizing
the costs and inconvenience caused by the changes. The proposed
method to solve the problem addressed in this dissertation is a
algorithm based on GRASP (Greedy randomized adaptive search
procedure) metaheuristic. The efectiveness of the proposed method
is tested on a large number of generated instances and on a real
network. Computational experiments demonstrate the efectiveness
of the proposed approach
Sinopse da FEEC
Keywords: Combinatorial optimization, Heuristic, Heuristic
programming
results suggest that the impairment of antigen presentation by
macrophages that interiorized NT1 was responsible for the
reduction of proliferative response of encephalitogenic T cells with
a consequent reduction of the severity of EAE
Keywords: Carbon nanotubes, Antigen, Immunology accessory
cells
IN VIVO ADMINISTRATION OF NON
FUNCTIONALIZED CARBON NANOPARTICLES T
AND B LYMPHOCYTES RESPONSE
Administração in vivo de nanotubos de carbono
não funcionalizados na resposta de linfócitos T e
B.
Ana Carolina Pimenta Grecco
Supervisor: Vitor Baranauskas (DSIF)
Defense date: Jan,30 2009
Abstract: Carbon nanotubes are currently under scrutiny as new
tools for biomedical applications. Previous studies have shown that
inhalation of carbon nanoparticles elicited an inflammatory
response in the lung tissue; however the effect of these particles in
the adaptive arm of the immune response deserves more attention.
Thus, three different preparations of carbon nanotubes (NT1, NT4,
NT5) were tested on in vivo T and B lymphocytes response of
C57Bl/6 mice. The multi-walled carbon nanotubes NT1 and NT4
were produced in our facilities and their effect on adaptive
immune response was compared to commercial carbon nanotubes
(NT5). The preparation (NT4) has demonstrated some cytotoxic
effects and was inappropriate for use in vivo. No cytotoxicity was
observed in the other preparations when administered
systematically in vivo. Carbon nanotubes NT1 and NT5 lead to a
significant activation of the T and B lymphocytes. The systemic
administration of these structures resulted in increased
proliferative response oflymphocytes to nonspecific mitogen
ConA, augmented the mRNA cytokines expression such as TNFa,
IL-6, IL-10 and significant decrease of TGFß. Nanostructures
induced significant increase in the production of antibody to a
specific antigen (OVA). These results emphasize the importance of
studying the immune response induced by the nanoparticles before
functionalizing them with proteins, DNA or for drug delivery
purpose
Keywords: Carbon nanoparticles, T cells immune response,
Production of antibody
NON FUNCTIONALIZED CARBON NANOTUBES
SUPRESS THE EXPERIMENTAL AUTOIMMUNE
ENCEPHALOMYELITIS BY IMPAIRING THE NEUROANTIGEN PRESENTATION
Nanotubos de carbono não funcionalizados
suprimem a encefalomielite experimental
autoimune prejudicando a apresentação do neuroantígeno.
Érika Mizutani
Supervisor: Vitor Baranauskas (DSIF)
Abstract: Carbon nanotubes are currently under scrutiny as new
tools for biomedical applications. However, the individual
exposure to inert particles have been associated with the
development of autoimmune diseases Here the effect of carbon
nanotubes (NT1) on macrophages activities and on the
development of experimental autoimmune encephalomyelitis
(EAE) an experimental model of multiple sclerosis was studied.
Evidence is provided that macrophages interiorized the carbon
nanotubes marked with fluorescent dye. The interiorization of the
NT1 resulted in significant increase in the production of TNF ,
suggesting a pro-inflammatory property of NT1. The
immunization of Lewis rats with myelin basic protein (MBP) in
the presence of NT1 resulted in a significant reduction of the
severity of EAE. The systemic administration of NT1, 10 days
after the immunization with MBP did not alter the evolution of the
disease. Moreover, a significant reduction of the proliferative
response of the encephalitogenic T cells co-cultured in the
presence of NT1, macrophages and MBP was observed. These
SUSPENDED-MEMBRANE RESISTIVE
MICROBOLOMETERS
Microbolômetros resistivos em membrana
suspensa.
Felipe Lorenzo Della Lucia
Supervisor: Jacobus Willibrordus Swart (DSIF)
Abstract: This work has as a main goal to develop the resistive
microbolometers technology that will be used as infrared sensors.
In order to do so, an initial device design was performed using
mathematical calculations and computational simulations were
accomplished to predict the behavior and adjust the fabrication
process parameters of this device to improve its performance.
After the simulations, the fabrication was performed. Using
Polysilicon as active element of the resistive microbolometers,
suspended membranes were fabricated to enhance thermal
isolation. Gold Black (porous) was evaporated to work as an
infrared radiation absorber. Some problems that occurred during
the fabrication were reported, solved and provided feedback to
simplify and improve the fabrication. Some Scanning Electron
Microscopy images and cuts using Focused Ion Beam show some
fabrication details, indicating the materials used and how the
Polysilicon membrane is isolated from the substrate. The
measurements performed in the fabricated device show that the
responsivity is about 1.8 V/W, the TCR is about -0.95%/K, the
response time is 13 ms and the specific detectivity is 5,66.105
cm.Hz1/2.W-1. Although some of these characteristics are not
within the designed parameters, others are similar to the
characteristics of commercial devices and devices found in
literature. As a result of this work, a favorable environment was
prepared to the development of this kind of device. Arrays of
devices can also be developed in order to produce infrared images
which may be used in many different applications
Keywords:
Bolometers,
Microbolometers,
Infrared,
Microfabrication, Semiconductors
ELETROMECHANICAL PLATFORM FOR ANKLE
SPRAIN SIMULATION AND MEASURE OF THE
MUSCLE REACTION TIME BY
ELECTROMYOGRAPHY
Plataforma eletromecânica para simulação de
entorse de tornozelo e medida de tempo de
resposta muscular através de eletromiografia.
Felipe Walter Dafico Pfrimer
Supervisor: José Antônio Siqueira Dias (DEMIC)
Abstract: This work presents the design of a electromechanical
platform that simulates an ankle sprain movement in order to
measure the electromyographic time response of the ankle
muscles. A new technique was employed to measure the initial
time of the ankle movement, when the platform starts to fall. This
technique uses a precision potentiometer to measure the angular
position of the falling platform, so that all mechanical errors which
are inherent to the system and cause errors in the evaluation of the
initial time of the movement can be totally eliminated. Two dataacquisition boards were designed and implemented. The first board
measures the reaction of the ankle muscles, and is basically an
electromyograph. The second board is measures both the weight
on each feet of the patient, and the angular position of the falling
platform as a function of the time. Both signal processing boards
communicate with a computer through USB ports, where a
software especially created for the system, developed in
LabVIEW, receives and calculates several parameters from the
19
data acquired from sensors. The system was tested in subjects
without ankle sprain history, presenting excellent results. The
electromyograph, developed as a part of the platform, can be used
in stand-alone mode, in any application where electromyographic
measurements are necessary
Keywords: Electronic circuits, Electronic instruments, Ankle,
Electromyograph
A SIMPLIFIED SYSTEM FOR POWER LINE DATA
COMMUNICATION : CIRCUIT DESIGN, PROTOTYPE
AND INTEGRATION PROPOSAL
Um sistema simplificado para transmissão de
dados em rede de energia elétrica: concepção do
circuito, protótipo e proposta de integração
Celso Coslop Barbante
Supervisor: Luiz Carlos Kretly (DMO)
Defense date: Apr,01 2009
Abstract: It was developed in this work a circuit for power line
data communication - PLC that enable low speed data transmission
in a circuit topology that enable a future integration. The built
prototype was elaborated with discrete components and exhibits a
compatible operation with a typical PLC circuit. The coupling
circuits with the mains wires are extensively discussed. The signal
to be serially transmitted pass through a level shifter that allows a
level and offset adjust of the signal, later being applied to a voltage
controlled oscillator - VCO that performs the continuous FSK
modulation in a simplified way. Bit Error Rate (BER)
measurements were made, and the results presented numerically
and graphically. A monolithic integrated circuit for the VCO, part
of this system, was projected foreseen a possible future integration.
For this task was performed simulation in the ADS circuit
simulator and later in the project flow an integrated circuit layout
was made using Cadence EDA tools. The chosen design kit comes
from AMS foundry, in the technology AMS C-35, and shows the
system integration viability in a single integrated circuit
Keywords: Electronic data interchange, Transmission of data
NEW TECHNIQUE FOR THE IMPLEMENTATION OF
DIGITAL DEMODULATION OF FIBER OPTIC
GYROSCOPES
Implementação de uma nova técnica para
demodulação digital de sinal de giroscópio a fibra
óptica.
Alécio Pontes Fernandes
Supervisor: Elnatan Chagas Ferreira (DEMIC)
Abstract: Gyroscopes are devices used to measure angular
orientation, being extensively employed ;for guidance, navigation
and stabilization. Among the many types of gyroscopes, IFOG
;(Interferometer Fiber Optic Gyroscope), based on Sagnac effect,
is the most interesting solution ;due to its high sensitivity,
resolution, reliability, small size and EMI immunity. The present
work ;describes a digital electronic circuit implementation for
open-loop IFOGs using zero-crossing ;demodulation techniques.
The technique used in the electronic circuit described in this work
;employs a quasi-synchronous clock for signal processing which
leads to an accurate, simple and ;low cost digital demodulation
scheme. The experimental results of the prototype showed that the
;final detection resolution is 1000 times better than one achieved
by the conventional synchronous ;clock zero-crossing digital
demodulator.
Keywords: Optics gyroscopes, Modulators (Eletronics), Signal
processing, Signal detection, Optical detectors
20
MUTATION ANALYSIS FOR SQL DATABASE
APPLICATIONS
Análise de mutantes em aplicações sql de banco
de dados.
Andrea Gonçalves Cabeça
Supervisor: Mario Jino (DCA)
Abstract: Testing database applications is crucial for ensuring
high quality software as undetected faults can result in
unrecoverable data corruption. SQL is the most widely used
interface language for relational database systems. Our approach
aims to achieve better tests by selecting fault-revealing databases.
We use mutation analysis on SQL statements and discuss two
scenarios for applying strong and weak mutation techniques. A
tool to support the automatization of the technique has been
developed and implemented. Experiments using real applications,
real faults and real data were performed to: (i) evaluate the
applicability of the approach, and (ii) compare fault-revealing
abilities of input databases
Keywords: Software development database, SQL (Computer
software language), Computer software testing, Software
enginering
INTEGRATED DISPATCH OF THERMOELECTRIC
GENERATION AND PRODUCTION AND
TRANSPORT OF NATURAL GAS WITH NEWTON'S
METHOD
Despacho integrado da geração termelétrica e da
produção e transporte de gás natural com método
de Newton.
Elma Pereira Santos
Supervisor: Takaaki Ohishi (DENSIS)
Abstract: Natural gas is a fossil fuel that can be used in industry,
trade, residence and vehicles, among others. An important
application of natural gas is as a primary source for electricity
generation in thermoelectric power plants. In the Brazilian Electric
System this source increase the system stability, once it is less
dependent of the water level in tanks to serve the demand for
power. As natural gas storage it is more complex and expensive,
the amount of gas directly affects the production and transportation
stages, once the entire amount that is produced and transported
must be consumed. Thus, the operation of the supply system of
natural gas is strongly dependent on decisions of their consumers.
The thermoelectric power plants are among the largest gas
consumers, so the dispatch of thermoelectric plants affects strongly
the gas system operation. On the other hand, restrictions in the gas
supply system may also affect the operation of thermoelectric
plants. This strong operative dependence between these two kinds
of systems, requires a coordinated operation with the aim of
obtaining a more efficient and safer operation. This thesis presents
a model of economic dispatch applied to thermoelectric power
plants that use natural gas as a primary energy source, considering
the costs of production, transportation of the natural gas and
electricity generation. The mathematical modeling results in a
nonlinear mixed problem. For resolution was used a hybrid
approach that combines a model based on Linear Programming
and a nonlinear. The nonlinear problem is solved by the Newton's
method. ;
Keywords:
Natural
gas,
Method
Newton-Raphson,
Thermoelectricity, Steam power plants
Sinopse da FEEC
chapter presents the conclusions and the perspectives of new
developments of this work
Keywords: Switching theory, Electronic apparatus and
appliances, Flyback
Electrical Energy
FUZZY INFERENCE SYSTEMS APPROACH FOR
LONG TERM HYDROTHERMAL SCHEDULING
Sistema de Interferência Nebulosa Aplicado ao
Planejamento da Operação Hidrotérmica de Médio
Prazo.
Bruno Monte
Supervisor: Secundino Soares Filho (DENSIS)
Abstract: The long term hydrothermal scheduling lies in the
optimization of the water resource usage through the maximization
of the hydroelectric production and the minimization of the
thermal plants operation. Its goal is to assure an economic and
reliable load supply throughout the study stages. This problem can
be characterized by exhibiting a complex nature, since its
characteristics define it as a large scale, dynamic, stochastic and
nonlinear problem. Although many optimization approaches have
already been proposed to answer the hydrothermal scheduling
problem, until now, there is no unanimous approach that is able to
cope efficiently with all the problem issues. Dynamic
Programming, which is one of the most commonly used
techniques to deal with this problem, is limited regarding its
application on real systems since its computational requirements
tend to be heavy. In this work we proposed an alternative approach
to deal with the long term hydrothermal scheduling. The proposed
technique is based on an Adaptive Neuro-Fuzzy Inference System
working in parallel with a deterministic optimization model with
perfect inflows forecasting. The optimal operation information is
processed by the network that produces fuzzy rules describing the
optimal decisions of the plant through the definition of the amount
of discharge in each stage and depending on the chosen input
variables. The performance of the proposed Neuro-Fuzzy approach
was compared to other policies, including Deterministic Dynamic
Programming, Stochastic Dynamic Programming and Open- Loop
Feedback Control, by simulation using historical inflow records of
five different Brazilian hydroelectric power plants. The results
demonstrated that the Neuro-Fuzzy approach provided similar and
competitive performance to less computationally efficient and
commonly used policies
Keywords: Hydrothermal Scheduling, Hydroelectric power
generation, Power systems, Fuzzy neural networks, Optimization
methods
SWITCH MODE POWER SUPPLY SCALABILITY FO
USE IN HOME APPLIANCES
Escalabilidade de fonte de alimentação chaveada
para uso em eletrodomésticos.
Gustavo Ortenzi
Supervisor: José Antenor Pomilio (DSCE)
Abstract: This work describes the development of a switch mode
power supply to be used at home appliances, capable to deliver
three outputs with voltage and power different levels, changing a
minimum number of components between them. At the first part of
the work is presented the application of the power supply and its
needs, followed by the specifications and choose of the topology
and the operation mode. Continuing the design of the power
supply's project, it is presented the methodology adopted to
calculate and select the components to be used. With the
components selected, it is presented the components selection
criteria looking the scalability strategy. Ending the component's
calculation and selection, the power supply schematic and the
components that change according to the used version are shown.
After the design, experimental results of the output cross
regulation, main waveforms of voltage and current, efficiency and
transient response of the three versions considering different AC
Mains voltages are shown. Closing the experimental results, the
EMI/EMC tests are presented, presenting the preliminary results,
followed by the adopted modifications and solutions. The last
PROTECTION AND CONTROL SYSTEMS ANALYSIS
OF INDUSTRIAL PLANTS WITH SYNCHRONOUS
GENERATORS DURING ISLANDED OPERATION
Análise dos sistemas de proteção e controle de
instalações industriais com geradores síncronos
durante operação ilhada.
Fernanda Caseño Lima Trindade
Supervisor: Walmir de Freitas Filho (DSEE)
Abstract: Modern industrial systems are very sophisticated
installations with a high number of automatic processes and
capability of isolated (islanded) operation after contingences by
using onsite generators composed mainly by synchronous
machines and steam turbines. Such installations, in the presence of
generators, are generically called autoproducers. Since many of
these autoproducers are connected to electrical power distribution
and subtransmission grids, they must respect the technical
recommendations imposed by these utilities. As a consequence,
the disconnection of these systems from the grid after islanding
occurrence is a mandatory procedure. ;Soon after the islanding
detection by the industrial protection system, the industry and the
grid must be electrically separated (isolated) by opening the circuit
breaker installed at the low voltage side of the interconnection
transformer. Thus, after the separation, the utility can carry out the
necessary technical procedures to restore the network. From the
industrial system perspective, after the separation, it is necessary to
take control actions to guarantee that the industrial system
continues operating with quality and reliability. Basically, three
actions must be taken: (a) change the operation mode of the speed
governor and excitation system of the generators; (b) implement
the load shedding system and (c) change the settings of the
protection system overcurrent relays. In this context, the objective
of this master thesis is to investigate these procedures and propose
methods for analysis in order to obtain a better understanding of
these issues. With this methodologies development, it is expected
that new automatic proceedings can be achieved in a more efficient
and systematic way
Keywords: Synchronous generator, Load shedding, Industrial
plants
COMPARISON BETWEEN MODELS NEWAVE AND
ODIN FOR LONG-TERM HYDROPOWER
SCHEDULING OF THE BRAZILIAN SYSTEM
Comparação entre os modelos newave e odin no
planejamento energético do sistema interligado
nacional.
André Emilio Toscano
Supervisor: Secundino Soares Filho (DENSIS)
Abstract: The optimization models applied to hydrothermal
scheduling on the Brazilian National Interconnected System (SIN)
shall provide the order of hydrothermal generation that meets the
Brazilian market of electric energy in a way that the demands of
power are attended and the operating costs, minimized. Due to the
hydroelectric predominant feature in the Brazilian system, the
planning aim to determine the optimal hydroelectric generation
that minimizes the thermoelectric supplementation necessary to
attend the power demands of Brazilian SIN. The long-term
hydrothermal scheduling plan model operating nowadays in the
Brazilian electrical system is the NEWAVE, a stochastic model
that represents the system by equivalent subsystems of energy,
through composite reservoirs, and has its solution decompounded
of individualized plants by other models, like the DECOMP and
SUISHI-O. The ODIN model is the energy planning methodology
developed at UNICAMP that treats indirectly the stochasticity of
21
affluent flows. This is done by means of an inflow predictor and an
optimizer for individual plants, thats provide the planning
decisions at each interval to order the hydrothermal scheduling
considering the provided flow generation for each plant and the
optimization of the hydraulic generation of the system. This work
presents a comparison of performance between the models of
hydrothermal scheduling NEWAVE and ODIN, in their
obtainment of optimized hydrothermal scheduling for the Brazilian
SIN
Keywords: Hydrothermal electric power systems, Computer
simulation
SENSOR OF FIELD MILL MEASUREMENT
Sensor para medição do campo elétrico.
Valeria Cristiane Silva
Supervisor: José Pissolato Filho (DSCE)
Abstract: This paper presents the development and construction
of a sensor used to detect intensity ;of electric field and
consequently of lightning. The sensor diameter of 10 cm consists
of a ;plate consisting of four revolving vanes that has its rotation
controlled by a small motor ;to 12000 rpm and a fixed plate, called
a measuring board, composed of eight vanes that ;are responsible
for produce a alternating voltage electric field concerning which
the sensor ;is subjected. When the rotor (revolving vanes) turns on
the stator (plate measurement), it ;exposes the plate for measuring
the electric field alone, and the field when this is over it. Thus ;is
cut to the normal static electric field or which varies very slowly.
The electric field meter ;(EFM - the English Electric Field Mill)
creates a field "variable" that will induce an electric ;charge in the
stator. The magnitude and polarity of the load are dependent on the
magnitude ;and polarity of the electric field. The measurement
plate generates a measurement signal of ;the order of millivolts,
requiring the use of amplifiers to make it significant for analysis.
The ;amplified signal is then digitized and sent to a software for
visualization of data generated ;by the sensor. In this work it is
also a study of origin of cargoes in the clouds, formation of ;storm
as well as training and classification of rays.
Keywords: Electric field mill, Atmospheric discharges, Loaded
origin in clouds, Formation of rays
FAST ADAPTIVE SINGLE-PHASE
AUTORECLOSING BASED ON SECONDARY ARC
VOLTAGE HARMONIC SIGNATURE
Religamento monopolar adaptativo rápido baseado
na assinatura harmônica da tensão de arco
secundário.
Allan Alves Montanari
Supervisor: Maria Cristina Dias Tavares (DSCE)
Abstract: This work presents a fast adaptive single-phase
autorec1osingseheme to optimize the ;period between the tripping
operation and the rec10sure of the faulted phase breakers. The
;adaptive proteetion quiekly reeomposes the eleetric power
transmission, minimizing the ;probability of severe damages
propagation in the system. ;The method is based on the analysis of
secondary are field tests data that were ;generated and monitored
in an infra-structure which consists of a real transmission line
;section (three towers and two spans). The harmonic content of the
secondary are voltage and ;eurrent was analyzed by the application
of Short Time Discrete Fourier Transform. Such ;analysis made it
possible to implement a statistical approach in order to obtain the
secondary ;are harmonic signature. ;Single-phase faults computer
simulations were performed using the data obtained from ;the
secondary are tests. It was developed an algorithm based on the
voltage harmonic content ;of the faulted phase, which was
ea1culated by shifting a window on the analyzed signals ;(Short
Time Discrete Fourier Transform). The algorithm determines the
secondary are ;existence and provides information in order to
suceessfully rec10se the circuit breaker. The ;method also presents
22
a control mechanism responsible for identifying whether the fault
is a ;permanent one or a transient fault.
Keywords: Overhead electric lines, Transients (Electricity)
USE OF THE DIRECT CURRENT LINK FOR THE
ELECTROMECHANICAL OSCILLATIONS DAMPING
IN ELECTRIC POWER SYSTEMS
Utilização do elo de corrente contínua para o
amortecimento de oscilações eletromecânicas em
sistemas de energia elétrica.
Diogo Totti Custódio
Supervisor: Vivaldo Fernando da Costa (DSEE)
Abstract: This dissertation presents a study about the HVDC
(High Voltage Direct Current) link contribution for damping low
frequency electromechanical oscillations when Electric Energy
System suffers small-signal disturbances. The HVDC link
components models were included in the Power Flow method as
well as the steady-state characteristics of the dynamic devices
(current or power controls modeling). It was utilized the MSP
(Power Sensitivity Model) to include the generators dynamic
model, automatic voltage regulators, HVDC link current controls
to perform the modal analysis. For damping the electromechanical
oscillations, it was designed a POD (Power Oscillation Damping
Controller) to include a supplementary signal added to reference
signal of the rectifier current or power controller, in order to
modulate these HVDC link quantities. The design of controller and
stability analysis are based on frequency response techniques and
modal analysis. The results obtained shown the HVDC link
viability for damping electromechanical oscillations
Keywords: Electric energy systems, Oscillations, Stability
OPTIMAL PLACEMENT OF VOLTAGE
REGULATORS IN DISTRIBUTION SYSTEMS
Alocação ótima de reguladores de tensão em redes
de distribuição de energia elétrica.
Carlos Alberto Nogueira Pereira
Supervisor: Carlos Alberto de Castro Junior (DSEE)
Abstract: This dissertation reports the development of a heuristic
method for sizing and allocating voltage regulators in distribution
radial primary feeders. The goals are to improve the voltage
profile, to minimize the real power losses and to minimize
equipment installation and maintenance costs. The proposed
algorithm for the optimal allocation of voltage regulators in radial
distribution networks comprises two steps. The first step aims to
select, install and set the tap of voltage regulators at buses that
result in the best technical conditions (smallest voltage deviation
and real power losses reduction). In the second step, an attempt is
made to reduce the number of voltage regulators initially allocated
in the first step, by moving them appropriately until the best
economical condition (minimum installation and maintenance
costs) is reached. A computational program was implemented to
evaluate the efficiency of the proposed method. Simulations have
been carried out for theoretical and realistic distribution systems,
for light and heavy load conditions, and the method showed to be
fast and efficient, providing reliable results. Simulations results for
a 70-bus distribution system and the comparison with those
provided by another method proposed in the literature are shown.
Also, simulation results are shown for realistic 136-, 202-, and
400-bus realistic systems
Keywords: Electric power systems control, Electric power
distribution systems, Heuristics
Sinopse da FEEC
function. At microwave frequencies, however, concentrated
parameter elements - resistors, inductors and capacitors - do not
behave as expected, and the output of an electric circuit at this
frequency is not like the projected one. To implement this electric
circuit, one needs to develop electromagnetic concepts, such as a
very important tool, called impedance inverter, and its equivalent
electromagnetic coupling. To restrain the scope of this work, we
choose to develop bandpass filters of narrow bandwidth, the most
common type used at microwave applications. The conversion
from the electric circuit obtained for a circuit made by distributed
parameter elements is shown and closes the theoretical cycle of
this work. Regarding laboratory experimental practices,
parameters are measured towards the characterization of the
designed electromagnetic filter by means of a rigorous statistics
analysis. The results obtained show that it is possible to begin with
an abstract mathematical function and to end up with a microwave
device that exhibits the designed response. Besides, the use of
ceramics with high permittivity led to the development of new
techniques for feeding the filters like the ones presented here, and
the requirement of having a big stopband led to the development of
a new geometry for the ceramics used to build the filter
Keywords: Dielectric Filters, Microwave device, Microwave
filters
OPTICAL FIBERS WITH OPTIMIZED PROFILES FOR
PARAMETRIC AMPLIFIERS
Fibras ópticas com perfis otimizados para
amplificadores paramétricos
Lucas Heitzmann Gabrielli
Supervisor: Hugo Enrique Hernández-Figueroa (DMO)
Abstract: The proposal of this work is to design optical fiber
profiles for parametric amplifiers both wideband, and robust with
respect to fabrication. We implement an efficient method to
compute the modes of multilayered optical fibers in order to
calculate the fiber dispersion. Using a standard genetic algorithm,
we optimize the profiles aiming at placing the zero dispersion
wavelengths at the center of the desired amplification band, and
making them robust to geometrical deformations. Finally, we
evaluate the performance of the designed profiles against others
more commonly employed in fiber amplifiers. We include a
fluctuation model in the fiber fabrication parameters to effectively
demonstrate the evolution in robustness in the optimized profiles.
The evaluations were conducted based in two methods: the fourwave model, and the SSFM (Split-Step Fourier Method), used to
validate the former. As results we present: (a) fiber profiles with
optimized properties for parametric amplifier construction; and (b)
statistical data collected from our models about the effects of
geometric fluctuations in the fabrication of the fibers and also in
the performance of parametric amplifiers
Keywords: Optical amplifiers, Optical fibers, Genetic algorithms
MODELING OF WELDING MACHINES FOR
ELECTROMAGNETIC INDUCTION IN RF
Modelagem de máquinas de solda por indução
eletromagnética em RF.
Joice Luiz Jeronimo
Supervisor: Hugo Enrique Hernández Figueroa (DMO)
Abstract: This work is related to the study of electromagnetic
weld industrial machines operating in radio frequency band aiming
robust models based on concentrated parameters circuits.
Typically, those machines have three steps: the power source
(electromagnetic energy generation), shielding and filtering
(through cavity) and load power supply. Since the equipment
demands high power (dozen of KVs), the power source consists of
a valve oscillator of 20-50MHz bandwidth. The power source
excites a cavity that resonants and works like a storing of
electromagnetic radiation and a frequency filter. Finally, the cavity
energy is extracted through a device that works like a transmission
line and sent to the load, that means, the material to be welded.
The proposed models use efficient equivalent circuits found for the
machine valves and cavities, and they were validated through
detailed experiments on a machine produced for a Brazilian
company, leader of the Latin American market.
Keywords: Transmission lines, Resonant cavities, Industrial
machinery, Oscillator valve
MINIATURIZATION TECHNIQUES FOR DIELECTRIC
FILTERS AT MICROWAVE FREQUENCIES
Técnicas de miniaturização de filtros dielétricos em
microondas.
Fabiano Rodrigo Borges
Supervisor: Hugo Enrique Hernández Figueroa (DMO)
Abstract: This work shows the development of a filter at
microwave frequencies and its construction by means of dielectric
resonators of high electric permittivity. Starting by the
mathematical definition of a transfer function such as the kind
input-output, which characterizes the filter, and the use of network
synthesis theory, shown in a very simply way, one shows how to
built an electric circuit that implements the filter's transfer
COMPRESSION OF ELECTROCARDIOGRAMS
USING WAVELETS
Compressão de eletrocardiograma usando
wavelets
Cristiano Marcos Agulhari
Supervisor: Ivanil Sebastião Bonatti (DT)
Abstract: The main contribution of the present thesis is the
proposition of two electrocardiogram (ECG) compression
methods. The first method, called Run Length Encoding
Adaptativo (RLEA), is based on wavelet transforms and consists
of using a wavelet function, obtained by the resolution of an
optimization problem, which fits to the signal to be compressed.
The optimization problem becomes unconstrained with the
parametrization of the coefficients of the scaling filter, that define
uniquely a wavelet function. After the resolution of the
optimization problem, the wavelet decomposition procedure is
applied to the signal and the most significant coefficients of
representation are retained, being the number of retained
coefficients determined in order to satisfty a pre-specified
distortion measure. The retained coefficients are quantized and
compressed, likewise the bitmap that informs the positions of the
retained coefficients. The quantization is performed in an adaptive
way, using different numbers of bits for the different
decomposition subspaces considered. Both the values of the
retained coefficients and the bitmap are encoded using a modified version of the Run Length Encoding technique. The second
method proposed in this dissertation, called Zero Padding Singular
Values Decomposition (ZPSVD), consists of detecting the beat
pulses of the ECG, equalizing the pulses by inserting zeros (zero
padding), and finally applying the SVD to obtain both the basis
and the coefficients of representation of the beat pulses. Some
components of the basis are retained and then compressed using
the same procedures applied to the coefficients of decomposition
of the ECG in the RLEA method, while the coefficients of
projection of the beat pulses in the basis are quantized using an
adaptive quantization procedure. Both proposed compression
methods are compared to other techniques by means of numerical
experiments
Keywords: Data compression, Electrocardiograms, Wavelet
A STUDY ON A CLASSIFIER OF MUSICAL SIGNALS
Estudos sobre uma ferramenta de classificação
musical.
Erica Moura Pereira
Supervisor: Amauri Lopes (DECOM)
23
Abstract: This work presents the results of some investigations
on an automatic musical signal classifier proposed in the literature
and notable by its solutions and performance. The objectives were
to analyze the viability of extending the applicability of the
classifier over new taxonomies, distinct from that proposed by the
authors, and to reduce the computational effort demanded by the
training process. A new computer implementation of the classifier
was developed and validated using the original database. The
investigations on the applicability used a new taxonomy, smaller
than the original, and showed a performance similar to the original
and that the classifier can be applied to taxonomies different from
the original. The new training process allowed a reduced
computational effort and assured the original performance level
Keywords: Taxonomy, Signal processing
METRICS APPLICATION IN METROPOLITAN
BROADBAND ACCESS NETWORK SECURITY
ANALYSIS
Aplicação de métricas à análise de segurança em
redes metropolitanas de acesso aberto.
Rodrigo Sanches Miani
Supervisor: Leonardo de Souza Mendes (DECOM)
Abstract: Information security has direct influence on any
successful deployment of metropolitan broadband access
networks. Efficient methods are required for security analysis of
metropolitan networks in all levels: organization, structure and
system. This work proposes the development and application of
specific security metrics for metropolitan broadband access
networks that aim to measure the efficiency of security programs
and support action planning against detected problems. The
approach presented in this work show metrics developed for these
networks and parameters for metrics definition, such as a model
for calculation of a security indicator of a metric. This paper also
presents results achieved from application of the metrics reported
here to establish security policies in the metropolitan broadband
access network of Pedreira, a city located in the state of São Paulo,
Brazil. These results show that well formed security metrics can be
efficient in vulnerability detection and solutions of security issues
Keywords: Information technology
MEMS SWITCHES APPLIED TO RF AND
MICROWAVE DEVICES : DESIGN, TECHNOLOGY
AND PHYSICAL IMPLEMENTATION OF PHASE
SHIFTER AND TUNABLE FILTER
Chaves mems aplicadas a dispositivos de rf e
micro-ondas: projeto, tecnologia e implementação
física de deslocador de fase e filtro sintonizável.
Paulo Filipe Braghetto Atanazio
Supervisor: Luiz Carlos Kretly (DMO)
Abstract: The purpose of this work is, based on transmission line
concepts, filter theory and the pioneer knowledge of this group
about RF MEMS Switches, propose two physical applications
employing this singular structure: a phase shifter and a tunable
filter at 0.1 - 35GHz range and Ku band respectively. A purely
electromechanical approach is done at the initial step, observing
the switch pull-in voltages for several structural geometries,
demystifying the mechanical hysteresis, intrinsic phenomena of
this kind of device. On the second phase of the work, the MEMS
switch electromagnetic behavior is detailed, strongly exploring the
electrical parameters extraction and its application on other types
of circuits. Finally, the tunable filter and phase shifter are
implemented through DMTL - Distributed MEMS Transmission
Lines - concepts, where frequency selection and the amount of
phase shifting are controlled by the variable switch capacitance
according to the applied DC control voltage
24
Keywords:
Micro-electrical-mechanical-systems
Hysteresis, Filter, Coplanar waveguide (CPW)
(MEMS),
GENERAL EXACT FORMULATIONS FOR THE
OUTAGE PROBABILITY AND FOR THE
PERFORMANCE OF A HYBRID COMBINING
METHOD IN WIRELESS COMMUNICATION
SYSTEMS
Formulações gerais e exatas para a probabilidade
de outage e para o desempenho de um método
híbrido de combinação de diversidade em sistemas
sem fio.
Flávio Du Pin Calmon
Supervisor: Michel Daoud Yacoub (DECOM)
Abstract: This work presents a useful, novel formulation for the
outage probability in wireless communication systems, here named
Joint Outage Probability (JOP). Given a set of signal-tointerferenceplus-noise ratio restrictions for mutually interfering
signals, the JOP corresponds to the probability that at least one of
the restrictions is not satisfied. A general exact solution for the
JOP is derived, along with a necessary and sufficient condition for
a non-trivial solution. In addition, a closed-form expression for the
JOP in an independent non-identically distributed Rayleigh
scenario is obtained. An application example of the formulations is
presented by a power allocation problem. In addition, this work
also introduces and investigates a general diversity combining
scheme, here named MRCS, in which maximal-ratio combined
signals are chosen on a selection combining basis. This combining
method has a simple implementation and a tractable analytical
formulation that can be directly applied to situations in which site
selection exists. A general analysis of the probability distribution
(reliability), level crossing rate, and average fade duration at the
output of the combiner is provided, along with examples for a
Nakagami-m fading environment. The main result of the MRCS
analysis, however, is the derivation of an exact, easy-to-evaluate
closed-form expression for the mean signal-to-noise ratio at the
output of the combiner. Such an expression is applicable for
conditions in which the product of the number of maximal ratio
combining branches and the Nakagami-m parameter is an integer
and it generalizes a result presented elsewhere in the literature. The
formulations derived here find a direct applicability in the
dimensioning of practical wireless networks
Keywords: Wireless communication systems, Probability,
Fading (Radio), Stochastic variables, Telecommunicatio
STUDY OF OPTIMIZATION TECHNIQUES FOR
DSPS CODES PROGRAMMING IN FPGA
Estudo de técnicas de otimização da programação
de códigos de DSP em FPGA.
José Matias Lemes Filho
Supervisor: Luís Geraldo Pedroso Meloni (DECOM)
Abstract: This work describes the study, research and
compilation of programming optimization techniques for FPGA
(Field Programmable Gate Arrays) using a tool technology for
rapid prototyping. For this purpose, some algorithms have been
implemented to help the presentation and evaluation of four
optimization techniques: alternative resources usage, time
multiplexing, alternative algorithms and systemic frequency
change. The main contributions of this work are: compilation in
one document several efficient techniques for generation code in
digital signal processing; study of the phases of design flow were
based on rapid prototyping tools; implementations of several
algorithms to demonstrate the optimization techniques, looking for
the minimization of the FPGA occupation area. With the use of
these techniques, it is possible to reach a FPGA area reduction of
up to 90%, depending of the complexity of the target system
Sinopse da FEEC
Keywords: FPGA Optimization, Rapid Prototyping Tools, Xilinx
system generator, Matlab/Simulink, Digital signal processing
Codes
poles of a given orthonormal basis. Such search directions can, in
turn, be used as part of an optimization procedure to locate the
minimum of a cost-function that takes into consideration the error
of estimation of the system output. The expressions relative to the
Kautz basis and to the GOBF are addressed. The proposed
methodology relies solely on input-output data measured from the
system to be modeled, i.e., no previous information about the
Volterra kernels is required. Simulation examples illustrate the
application of this approach to the modeling of linear and
nonlinear systems, including a real magnetic levitation system with
oscillatory behavior. At last, the representation of uncertain
systems based on models having structured uncertainty is studied.
The uncertainty of a set of Volterra kernels is mapped on to
intervals defining the coefficients of the orthonormal expansion.
Additional conditions are proposed to guarantee that all the
process kernels to be represented by the model, which allows
estimating the uncertainty bounds
Keywords: System identification, Nonlinear systems, Volterra
series, Orthonormal basis functions, Optimization
OUTAGE PROBABILITY ANALYSIS IN
GENERALIZED CHANNELS OF COMBINERS
UNDER COCHANNEL INTERFERENCE
Análise da probabilidade de outage em canais de
desvanecimento generalizados para combinadores
sob interferência co-canal.
Alexandre Campos Moraes
Supervisor: Michel Daoud Yacoub (DECOM)
Abstract: Diversity combining is an important technique usually
employed to alleviate the unwanted efects of the cochannel
interference. Equal-gain and maximal-ratio combining are
considered here, as they are two of the most important space
diversity methods. Unfortunately, the evaluation of the multifold
nested integrals required in the exact outage probability analysis of
such systems is not computationally feasible. In order to out ank
the complexity of this task, we present a simple approximate
method. In the proposed model, the system is composed of M
diversity branches and N arbitrary independent cochannel
interferers undergoing generalized fading channels, namely a-µ, kµ and n-µ. The approximate formulations are compared against
Monte Carlo simulation results and an excellent agreement
between them is achieved
Keywords: Wireless communication systems, Generalized fading
scenarios, Cochannel interface
Doctoral thesis
Automation
IDENTIFICATION OF NONLINEAR SYSTEMS USING
VOLTERRA MODELS BASED ON KAUTZ
FUNCTIONS AND GENERALIZED ORTHONORMAL
FUNCTIONS
Identificação de sistemas não-lineares usando
modelos de volterra baseados em funções
ortonormais de Kautz e generalizadas.
Alex Da Rosa
Supervisor: Wagner Caradori do Amaral (DCA)
Abstract: This work is concerned with the modeling of nonlinear
systems using Volterra models with orthonormal basis functions
(OBF). Volterra models represent a generalization of the impulse
response model for the description of nonlinear systems and, in
general, require a large number of terms for representing the
Volterra kernels. Such a drawback can be overcome by
representing the kernels using a set of orthonormal functions. The
resulting model, so-called OBF-Volterra model, can be truncated
into fewer terms if the basis functions are properly designed. The
underlying problem is how to select the free-design poles that fully
parameterize these functions, particularly the two-parameter Kautz
functions and the Generalized Orthonormal Basis Functions
(GOBF). One of the approaches adopted to solve this problem
involves minimizing an upper bound for the error resulting from
the truncation of the kernel expansion. Each multidimensional
kernel is decomposed into a set of independent Kautz bases, in
which every basis is parameterized by an individual pair of
complex conjugate poles intended to represent the dominant
dynamic of the kernel along a particular dimension. An analytical
solution for one of the Kautz parameters, valid for Volterra models
of any order, is derived. Other approach involves the numerical
optimization of orthonormal bases of functions used for
approximation of dynamic systems. This strategy is based on the
computation of analytical expressions for the gradients of the
output of the orthonormal filters with respect to the basis poles.
These gradients provide exact search directions for optimizing the
OPTICAL AND ELECTRICAL PROPERTIES OF
SILICON NANOSTRUCTURES
Propriedades ópticas e elétricas de nanoestruturas
de Si.
Guilherme Osvaldo Dias
Supervisor: Jacobus Willobrordus Swart (DSIF)
Abstract: In this work we have analyzed samples of Silicon Rich
Silicon Oxide (SRSO) obtained by an Electron Cyclotron
Resonance Chemical Vapor Deposition system (ECR-CVD).
Structural, compositional, electrical and optical properties were
investigated by Fourier transform infrared (FTIR), transmission
electron microscopy (TEM), Rutherford backscattering
spectroscopy
(RBS),
capacitance-voltage
(C-V),
photoluminescence (PL) and ellipsometry. By fitting a long range
refractive indices curve as a function of O2 flow, it can be seem
that the ECR-CVD system is able to produce films with high
control on the refractive indices, which, indirectly, suggest the
possibility of control of the optical and electrical characteristics,
since all these characteristics are dependent of Si concentration in
the film, as refractive index. Into the region of interest for our
work, the atomic concentration ratio O/Si obtained by RBS
correlates linearly with the refractive indeces. The PL intensities
and peak positions and the hysteresis curves observed by C-V
characterizations, after thermal treatments, show dependence on
O2/SiH4 flow ratios used in the work. We observed that
temperature and time of thermal treatments have strong influence
on PL properties of the selected samples. Nevertheless, the
influence of these same parameters on electrical properties (C-V)
are less significant than for PL properties, mainly for temperatures
above 1000 oC. The PL and CV characteristics of our samples can
be related to the presence of silicon nanostructures embedded
inside SRSO films. On the other hand, typical silicon oxide
defects, like NBOHC and ODC, have some influence on such
optical and electrical properties. Comparing our PL and FTIR data,
as well as data from literature, we can suppose that crystallinity
has strong influence on PL intensity. On the other hand,
crystallinity has just a weak influence on the charge storage
capacity of our samples, as we had seen by the hysteresis curves in
C-V measurements for samples treated at 1100 oC and 1150 oC.
Finally, we conclude that optical and electrical characteristics of
our samples are associated principally to the presence of silicon
nanostructures embedded in a silicon oxide matrix. Our samples
showed high potentiality to applications as optoelectronic and
nanoelectronic devices
Keywords: Silicon, Nanostructures, Silicon, Silicon
25
Biomedical Engineering
NON-LINEAR DYNAMICS OF EPILEPTIFORM
BURST AND ITS TRANSITION TO SPREADING
DEPRESSION
Dinâmicas não-lineares do burst epileptiforme e da
sua transição para a depressão alastrante.
Gerson Florence Carvalheira de Azevedo
Supervisor: José Wilson Magalhães Bassani (DEB)
Abstract: During the epileptiform burst and the spreading
depression (SD), it is observed an increase of [K+]o (extracellular
potassium concentration) and a decrease of [Ca2+]o (extracellular
calcium concentration), pointing out the participation of this
nonsynaptic mechanism in these abnormal oscillatory patterns.
These ionic variations raise the neuronal excitability. However,
whether the high [K+]o is a primary factor in the beginning of
these neuronal activities or just plays a secondary role into this
process is unclear. To better understand the nonlinear dynamics of
these patterns, the experimental conditions of high [K+]o and zero
[Ca2+]o were replicated in an extended Golomb model in which
we added important regulatory mechanisms of ion concentration as
Na+/K+ pump, ion diffusion and glial buffering. Within these
conditions, it was possible to simulate epileptiform burst within
the ictal phase. The SD was elicited by the interruption of the
Na+/K+ pump activity. The blockage of Na+/K+ pump by cellular
hypoxia is an experimental procedure to elicit SD, known as
hypoxic spreading depression - HSD. The bifurcation theory and
the method of fast-slow analysis were used to study the
interference of extracellular K+ in the cellular excitability. This
analysis indicates that the system loses its stability at a high [K+]o,
transiting to an elevated state of neuronal excitability. This raise of
[K+]o provokes bifurcations in the neuronal dynamic behavior,
that determine transitions between different stages of these
electrical activities. In the initial stage, the increase of [K+]o
creates favorable conditions to trigger the epileptiform burst and
the SD by saddle-node and supercritical Hopf bifurcations,
respectively. During the neuronal activity, the level of excitability
is maintained by a continuous growth of [K+]o that depresses K+
currents in a positive feedback way. At this stage, concerning
epileptiform burst, the amplitude and frequency of action
potentials are changed by supercritical Hopf bifurcation. At the
last stage, with the depression of K+ currents, the Na+/K+ pump
plays an important role in the end of neuronal activity. The
epileptiform burst and SD activities terminate by saddlehomoclinic orbit and saddle-node bifurcations, respectively. Thus,
this work suggests that [K+]o may play a fundamental role in the
nonlinear dynamics of the epileptiform burst and the transition to
SD
Keywords: Bioengineering, Neurology, Dynamical systems
CRUDE REGISTRATION OF RANGE IMAGES
THROUGH SIMPLIFIED MESHES
Pré-alinhamento de imagens de profundidade via
malhas simplificadas.
Mercedes Rocío Gonzalez Márquez
Supervisor: Wu Shin-Ting (DCA)
Abstract: The crude registration of two partially overlapping
range images from rigid objects consists of the determination of a
rigid transformation T which brings both images into the same
reference system. A crude registration should be independent of
data geometry, and be efficient, in the sense that has low time
complexity in finding the correspondence pairs. The most popular
solution consists of extracting n pairs of correspondences in the
overlapping regions and estimating from them the transformation
T. Current works on crude registration still present drawbacks in
relation to data geometry and efficiency. This work proposes an
26
alternative solution for crude registration. Based on the hypothesis
that the shape of an object is essentially captured by a finite subset
of its points, this thesis proposes the use of a simplified triangular
mesh, instead of a dense range image, to reduce the search space of
correspondences. Besides, the construction of a descriptor, called
trihedron is proposed. It has higher discriminating capacity which
makes correspondence search still more efficient. The proposed
algorithm has been validated through experiment tests with several
real images
Keywords: Three-dimensional imaging, Image processing,
Vision computer, Meshes, Modeling data
DECISION SUPPORT SYSTEM TO THE ANALYSIS
AND BUS LOAD FORECASTING
Sistema de suporte a decisão para análise e
previsão de carga por barramento.
Ricardo Menezes Salgado
Supervisor: Takaaki Ohishi (DENSIS)
Abstract: In a power operation system there are many variables
that can influence the execution of the control routines. the
attendance of these variables is very important to aid the processes
in the safe operation of the system. In the electric system the bus
load leve is an important variable in the operation planning step.
Accurate information on the load level in each bus provide a bette
control in the power flow, safe and security analysis, operation
programming, planning and others. Thus, this work presents two
contributions to the bus load forecasting area. The first
contribution is the development of a bus load forecast
methodology that executes and contribution is a computational
system for bus load forecasting named SysPrev - SupportSystem
for Bus Load Analysis and Forcasting - developed to facilitate the
bus forecasting process
Keywords: Decision Suport Systems, Electric Power Systems Load Dispotching, Artificial Intelligence, Cluster Analysis, Time
Series Analysis
FUZZY INFORMATION RETRIEVAL MODEL USING
MULTIPLE RELATED ONTOLOGIES
Modelo fuzzy para recuperação de informação
utilizando múltiplas ontologias relacionadas.
Maria Angelica de Andrade Leite
Supervisor: Ivan Luiz Marques Ricarte (DCA)
Abstract: With the World Wide Web popularity growth, more
people has access to information and this information volume is
expanding over the time. The information retrieval area has a new
challenge intending to search information resources by their
meaning. A way to retrieve information, by its meaning, is by
using a knowledge base that encodes the domain concepts and
their relationships. Nowadays ontologies are being used to model
knowledge bases. To deal with imprecison and uncertainty present
in the knowledge and in the information retrieval process, fuzzy
set theory techniques are employed. Preceding works encode a
knowledge base using just one ontology. However a document
collection can deal with different domain themes, expressed by
distinct ontologies, that can be related. In this work a way of
knowledge organization and representation, using multiple related
ontologies, was investigated and a new method of query expansion
was developed. The knowledge organization and the query
expansion method were integrated in the fuzzy model for
information retrieval based on mutiple related ontologies. The
model performance was compared with another fuzzy-based
approach for information retrieval and with the Apache Lucene
search engine. In both cases the proposed model improves the
precision and recall measures
Keywords: Query expansion, Knowledge representation,
Ontology, Fuzzy information retrieval
Sinopse da FEEC
UNSUPERVISED METHODS OF CLASSIFYING
REMOTELY SENSED IMGES USING KOHONEN
SELF-ORGANIZING MAPS.
Metodos de classificação não-supervisionada de
imagens de sensoriamento remoto usando mapas
auto-organizaveis de Kohonen
Márcio Leandro Gonçalves
Supervisor: Márcio Luiz de Andrade Netto (DCA)
Abstract: This thesis proposes new methods of unsupervised
classification for remotely sensed images which particularly
exploit the characteristics and properties of the Kohonen SelfOrganizing Map (SOM). The key point is to execute the clustering
process through a set of prototypes of SOM instead of analyzing
directly the original patterns of the image. This strategy
significantly reduces the complexity of data analysis, making it
possible to use techniques that have not usually been considered
computationally viable for processing remotely sensed images,
such as hierarchical clustering methods and cluster validation
indices. Unlike other approaches in which SOM is used as a visual
tool for detection of clusters, the proposed classification methods
automatically analyze the neurons grid of a trained SOM in order
to find better partitions for data sets of images. Based on the
statistical properties of the SOM, clustering validation indices
calculated in a modified manner are proposed with the aim of
reducing the computational cost of the classification process of
images. Image texture analysis techniques are applied to evaluate
and filter training samples and/or prototypes of the SOM that
correspond to transition regions between land cover classes.
Spatial information about the prototypes of the SOM, in addition
to multiespectral distance information, are also incorporated in
criteria for merging clusters with aim to facilitate the
discrimination of land cover classes which have high spectral
similarity. Experimental results show that the proposed
classification methods present significant advantages when
compared to unsupervised classification techniques frequently
used in remote sensing.
Keywords: Neural networks, Artificial intelligence, Digital
image processing, Remote sensing, Kohonen maps
CONSTRUCTION OF TOPOLOGICAL QUANTUM
CODES ON BIDIMENSIONAL MANIFOLDS
Análise e construção de códigos quânticos
topológicos sobre variedades bidimensionais.
Clarice Dias De Albuquerque
Supervisor: Reginaldo Palazzo Júnior (DT)
Abstract: In this work we present an extensive study of
topological quantum codes. As a consequence, new promising
ideas, concepts and results are also presented. First of all, new
toric quantum codes are constructed among which the [[d2,2,d]]
class stands out as the best known so far. This proposed
construction of toric codes is realized based upon group theory and
combinatorial analysis. Regarding the topological quantum codes
in surfaces with genus g = 2, we consider a construction method
based on hyperbolic geometry and so generalizing Kitaev's
construction. We reproduce and enlarge the class of quantum
codes with distance 3 as a consequence of the embedding of
complete graphs in surface with specific genus. This class was first
proposed by Bombin andMartin-Delgado. The latter class is
geometrically described and its parameters are explicitly exhibited.
We also obtain a class of MDS (Maximum Distance Separable)
codes in surfaces with genus g = 2,3,4 and 5, obtained by the
proposed construction are tabulated and analyzed
Keywords: Coding theory, Hyperbolic geometry, Lattice theory
27

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