Trends in Applied and Computational Mathematics
https://tema.sbmac.org.br/tema
<img src="/public/journals/1/capatema.jpg" alt="" width="305" height="418" align="left" hspace="5" /><p>The journal TEMA - Trends in Applied and Computational Mathematics - publishes original papers with innovative and/or relevant contributions to the field of Applied and Computational Mathematics. The journal began in 1999 as an initiative of the Brazilian Society of Computational and Applied Mathematics - SBMAC - with the aim of publishing the Proceedings of the Brazilian National Conference on Computational and Applied Mathematics - CNMAC. At that time, the creation of the journal TEMA was an opportunity for the Brazilian scientific community to disseminate the research presented at CNMAC. Later in 2006, with the increasing interest of the scientific Brazilian community, the journal TEMA started receiving manuscripts independent of the proceedings, accepting articles from the academic public in general, increasing the scope of this important publication.</p><p>Since the beginning, the criterions to compose the journal’s Editorial Board were based on competence and excellence in each field of expertise, always choosing renowned researchers from different regions from Brazil and also from abroad.</p><p>Submitted manuscripts should be original and follow the standards of international publishing. Manuscripts can be written in English or Portuguese. All articles should not exceed 20 pages in length, although longer papers may also be published under exceptional circumstances. The peer review is performed by at least two ad hoc anonymous reviewers, selected by the Editorial Board.</p><p>Currently, one volume of the journal TEMA is published per year, which comprises up to three (3) fascicles (numbers). Since 2014, only institutional members receive printed copies of the journal, that are responsible to supply their respective libraries. The on-line version of the journal is available in PDF format at <a href="http://www.tema.sbmac.org.br" target="_self">http://www.tema.sbmac.org.br</a> with free access to all scientific community.</p><p>The great number of submissions of manuscripts written in English language, in the past few years, from both Brazilian and foreigner researchers alike, indicate that the journal TEMA is nowadays recognized as an important publication in the field of Applied Mathematics, from both national and international scientific communities. As a consequence, since 2012, the journal TEMA was indexed in the SciELO database (<a href="http://www.scielo.br/tema" target="_blank">http://www.scielo.br/tema</a>).</p><p> </p><p><a href="/tema/about/submissions#onlineSubmissions" target="_self"><strong>SUBMIT A PAPER TO TEMA</strong></a></p>SBMACen-USTrends in Applied and Computational Mathematics1677-1966Ordinal Sums of De Morgan Triples
https://tema.sbmac.org.br/tema/article/view/1087
<pre><!--StartFragment-->In this paper we consider the ordinal sum of the summands <span>(a_i, b_i, T_i)</span> <span>((a_i, b_i, S_i))</span>, where <span>(T_i)_{i\in I}$</span> <span>$((S_i)_{i\in I})</span> are a family of t-(co)norms and <span>$(]a_i, b_i[)_{i\in I}$</span> a family of nonempty, pairwise disjoint open subintervals of <span>[0,1]</span>, and we characterize the ordinal sum of the summands <span>(a_i, b_i, N_i)</span> where <span>(N_i)_{i\in I}</span> are a family of fuzzy negations such that <span>N_i\geq N_S</span> and prove that the function <span>N</span> is a fuzzy negation. In addition, we prove if <span>(T_i, S_i, N_i)</span> is a De Morgan triple satisfy some specific conditions, then <span>(T, S, N)</span> is a semi De Morgan triple.<!--EndFragment--></pre>Ivan MezzomoBenjamin Bedregal
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219218110.5540/tema.2018.019.02.181An Error Bound for Low Order Approximation of Dynamical Systems Subjected to Initial Conditions
https://tema.sbmac.org.br/tema/article/view/1128
<p>In recent years, a great effort has been taken focused on the development of reduced order modeling techniques of dynamical systems. This necessity is pushed by the requirement for efficient numerical techniques for simulations of dynamical systems arising from structural dynamics, controller design, circuit simulation, fluid dynamics and micro electromechanical systems.</p><p>We introduce a method to calculate the minimum upper $\mathcal{L}_2$ error bound of a linear time invaritant reduced order model considering any possible unitary initial conditions (IC). As a consequence, the proposed method calculates the unitary IC vector which leads to the maximum $\mathcal{L}_2$ norm of the error. Based on this error bound, it is discussed the capacity of a reduced order system to approximate the free transient response in the worst case scenario.</p>Gabriel Pedro Ramos MacielRoberto Spinola Barbosa
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219219710.5540/tema.2018.019.02.197Numerical Solution of Heat Equation with Singular Robin Boundary Condition
https://tema.sbmac.org.br/tema/article/view/1092
<span class="fontstyle0">In this work we study the numerical solution of one-dimensional heat<br />diffusion equation with a small positive parameter</span><span class="fontstyle0"> subject to Robin boundary conditions. The simulations examples lead us to conclude that the numerical solutions<br />of the differential equation with Robin boundary condition are very close of the<br />analytic solution of the problem with homogeneous Dirichlet boundary conditions<br />when </span><span class="fontstyle0">tends to zero</span>German Lozada-CruzCosme Eustaquio Rubio-MercedesJunior Rodrigues-Ribeiro
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219220910.5540/tema.2018.019.02.209Generalized Exponential Bidirectional Fuzzy Associative Memory with Fuzzy Cardinality-Based Similarity Measures Applied to Face Recognition
https://tema.sbmac.org.br/tema/article/view/1090
Associative memories are biologically inspired models designed for the storage and recall by association. Such models aim to store a finite set of associations, called the fundamental memory set. The generalized exponential bidirectional fuzzy associative memory (GEB-FAM) is a heteroassociative memory model designed for the storage and recall of fuzzy sets. A similarity measure, that is, a function that indicates how much two fuzzy sets are equal, is at the core of a GEB-FAM model. In this paper, we present a detailed study on the use of cardinality-based similarity measures in the definition of a GEB-FAM. Moreover, we evaluate the performance of the GEB-FAMs defined using such measures in a face recognition problem.Aline Cristina SouzaMarcos Eduardo Valle
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219222110.5540/tema.2018.019.02.221Controle de um Sistema de Navegação de um Robô Ambiental Híbrido por meio de um Sistema de Inferência Fuzzy Hierárquico
https://tema.sbmac.org.br/tema/article/view/1100
<p align="LEFT">Apresenta-se, neste artigo, o desenvolvimento completo de um sistema de navegação auxiliar baseado na Lógica Fuzzy para um robô móvel denominado Robô Ambiental Híbrido Médio (RAHM). Apresenta-se também o projeto eletrônico e a programação do sistema de navegação. O desempenho deste sistema é avaliado frente ao do Sistema Principal de Navegação do RAHM.</p>Cristhian J GómezMarley VellascoRicardo Tanscheit
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219223510.5540/tema.2018.019.02.235Construção de Superfícies Suaves com Continuidade Geométrica
https://tema.sbmac.org.br/tema/article/view/1121
<div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p>No uso de métodos numéricos, principalmente o método dos elementos de contorno, a construção de superfícies suaves é um dos requisitos importantes para a modelagem computacional de sólidos. Adicionalmente aos métodos numéricos, existem muitos outros campos de aplicação, tais como, na animação computacional e na reconstrução de imagens médica, em que a continuidade geométrica G1 é condição fundamental para a geração de superfícies suaves. No presente trabalho é utilizada a técnica de construção de geometria a partir das curvas do contorno. Diferentemente das construções clássicas das funções aproximadoras C0, a presente construção G1 faz uso dos vetores normais nos vértices da malha triangular, além de suas coordenadas geométricas. No entanto, os dados de entrada, especialmente os vetores normais, não são de obtenção imediata para geométricas complexas. Com o intuito de contornar esta dificuldade, o presente trabalho desenvolveu um código computacional para construção de superfícies suaves acoplado com o software de computação gráfica Blender (TM). Desta forma, a implementação computacional tanto para a criação dos elementos triangulares com continuidade geométrica quanto para a obtenção das informações iniciais, via Blender (TM), é explicitada e sua eficiência é comprovada por meio de modelagem de geometrias globalmente paramétricas e não-paramétricas de complexidade variada.</p></div></div></div>Fabio Carlos da RochaHumberto Breves Coda
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219225510.5540/tema.2018.019.02.255Apnea Recognition with Wavelet Neural Networks
https://tema.sbmac.org.br/tema/article/view/1117
<span>Apnea is a Sleep Disorder Syndrome characterized by an interruption or reduction of air flow for at least 10 seconds. Polysomnography is a test used to apnea diagnosis. Several signals, including Electrocardiogram (ECG), Electroencephalogram (EEG) and Oxygen Saturation (SpO_2) are obtained in this diagnostic test. Since most tests for apnea are uncomfortable, there is an increase search for alternative methods to reduce cost and improve patient well-being.</span><br /><span>In this work, we use only SpO_2 data from 25 patients of the St Vincent's University Hospital, Dublin, to extract parameters connected to a Neural Network attempting to classify patients with apnea or non-apnea. Results confirm that our alternative method can be used as an auxiliary tool for diagnosis by using exclusively SpO_2 signal.</span>Cristina ZaniolMaria Cristina VarrialeEvandro Manica
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219227710.5540/tema.2018.019.02.277Modelo Entomológico Determinístico sob Efeito da Pluviosidade para o Aedes aegypti e o Aedes albopictus
https://tema.sbmac.org.br/tema/article/view/1157
<p>As espécies de mosquitos Aedes aegypti e Aedes albopictus destacam-se na dispersão de diversas arboviroses, dentre elas: a dengue, a febre amarela, a febre chikungunya e o zika vírus. Trabalhos na área de Biologia Matemática vêm sendo realizados recentemente no intuito de descrever a dinâmica da população destes vetores e, consequentemente, auxiliar os gestores públicos no controle destas arboviroses. Neste trabalho, apresentamos um modelo entomológico para descrever o ciclo de vida destas espécies de mosquito. Os coeficientes do modelo são fixados como dependentes da pluviosidade. Os resultados do modelo são validados por confrontação com dados experimentais de capturas de fêmeas A. aegypti para as cidades de Caratinga e Sete Lagoas, Minas Gerais, Brasil.</p>Lillia dos Santos Barsante SilvaRodrigo Tomas Nogueira CardosoJosé Luiz Acebal FernandesCarlos Alexandre SilvaAlvaro Eduardo Eiras
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219228910.5540/tema.2018.019.02.289A Comparison Among Simple Algorithms for Linear Programming
https://tema.sbmac.org.br/tema/article/view/1127
This paper presents a comparison between a family of simple algorithms for linear programming and the optimal pair adjustment algorithm. The optimal pair adjustment algorithm improvements the convergence of von Neumann's algorithm which is very attractive because of its simplicity. However, it is not practical to solve linear programming problems to optimality, since its convergence is slow. The family of simple algorithms results from the generalization of the optimal pair adjustment algorithm, including a parameter on the number of chosen columns instead of just a pair of them. Such generalization preserves the simple algorithms nice features. Significant improvements over the optimal pair adjustment algorithm were demonstrated through numerical experiments on a set of linear programming problems.Jair SilvaCarla T. L. S. GhidiniAurelio R. L. OliveiraMarta I. V. Fontova
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219230510.5540/tema.2018.019.02.305A New Scheme for Fault Detection and Classification Applied to DC Motor
https://tema.sbmac.org.br/tema/article/view/1155
This study presents an approach for fault detection and classification in a DC drive system. The fault is detected by a classical Luenberger observer. After the fault detection, the fault classification is started. The fault classification, the main contribution of this paper, is based on a representation which combines the Subctrative Clustering algorithm with an adaptation of Particle Swarm Clustering.Laércio I. SantosReinaldo M. PalharesMarcos F. S. V. D'AngeloJoão B. MendesRenê R. VelosoPetr Y. Ekel
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219232710.5540/tema.2018.019.02.327The Influence of Velocity Field Approximations in Tracer Injection Processes
https://tema.sbmac.org.br/tema/article/view/1172
Although the concentration is the most important variable in tracer injection processes, an efficient and accurate velocity field approximation is crucial to obtain a good physical behaviour for the problem. In this paper we analyse a Stabilized Dual Hybrid Mixed (SDHM) method to solve the Darcy's system in the velocity and pressure variables that involves the conservation of mass and Darcy's law. This approach is locally conservative, free of compromise between the finite element approximation spaces and capable of dealing with heterogeneous media with discontinuous properties. The tracer concentration is solved via a combination of the Streamline Upwind Petrov-Galerkin (SUPG) method in space with an implicit finite difference scheme in time. We also employ a semi-analytical approach (Abbaszadeh-Dehghani analytical solution) to integrate the transport equation. A numerical comparative study using the SDHM formulation, the Galerkin method and a post-processing technique to calculate the velocity field in combination with those concentration approximation methodologies are presented. In all comparisons, the SDHM formulation appears as the most efficient, accurate and almost free of spurious oscillations.Yoisell R. NúñezCristiane Oliveira FariaSandra M. C. MaltaAbimael F. D. Loula
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219234710.5540/tema.2018.019.02.347Sequences of Primitive and Non-primitive BCH Codes
https://tema.sbmac.org.br/tema/article/view/1078
In this work, we introduce a method by which it is established that; how a sequence of non-primitive BCH codes can be obtained by a given primitive BCH code. For this, we rush to the out of routine assembling technique of BCH codes and use the structure of monoid rings instead of polynomial rings. Accordingly, it is gotten that there is a sequence $\{C_{b^{j}n}\}_{1\leq j\leq m}$, where $b^{j}n$ is the length of $C_{b^{j}n}$, of non-primitive binary BCH codes against a given binary BCH code $C_{n}$ of length $n$. Matlab based simulated algorithms for encoding and decoding for these type of codes are introduced. Matlab provides built in routines for construction of a primitive BCH code, but impose several constraints, like degree $s$ of primitive irreducible polynomial should be less than $16$. This work focuses on non-primitive irreducible polynomials having degree $bs$, which go far more than 16.A. S. AnsariT. ShahZia Ur-RahmanAntonio A. Andrade
Copyright (c) 2018 Trends in Applied and Computational Mathematics
2018-09-122018-09-1219236910.5540/tema.2018.019.02.369