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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
171

Mathematical modelling in classroom: The importance of validation of the constructed model

Voskoglou, Michael Gr. 20 March 2012 (has links) (PDF)
No description available.
172

A framework of adaptive T-S type rough-fuzzy inference systems (ARFIS)

Lee, Chang Su January 2009 (has links)
[Truncated abstract] Fuzzy inference systems (FIS) are information processing systems using fuzzy logic mechanism to represent the human reasoning process and to make decisions based on uncertain, imprecise environments in our daily lives. Since the introduction of fuzzy set theory, fuzzy inference systems have been widely used mainly for system modeling, industrial plant control for a variety of practical applications, and also other decisionmaking purposes; advanced data analysis in medical research, risk management in business, stock market prediction in finance, data analysis in bioinformatics, and so on. Many approaches have been proposed to address the issue of automatic generation of membership functions and rules with the corresponding subsequent adjustment of them towards more satisfactory system performance. Because one of the most important factors for building high quality of FIS is the generation of the knowledge base of it, which consists of membership functions, fuzzy rules, fuzzy logic operators and other components for fuzzy calculations. The design of FIS comes from either the experience of human experts in the corresponding field of research or input and output data observations collected from operations of systems. Therefore, it is crucial to generate high quality FIS from a highly reliable design scheme to model the desired system process best. Furthermore, due to a lack of a learning property of fuzzy systems themselves most of the suggested schemes incorporate hybridization techniques towards better performance within a fuzzy system framework. ... This systematic enhancement is required to update the FIS in order to produce flexible and robust fuzzy systems for unexpected unknown inputs from real-world environments. This thesis proposes a general framework of Adaptive T-S (Takagi-Sugeno) type Rough-Fuzzy Inference Systems (ARFIS) for a variety of practical applications in order to resolve the problems mentioned above in the context of a Rough-Fuzzy hybridization scheme. Rough set theory is employed to effectively reduce the number of attributes that pertain to input variables and obtain a minimal set of decision rules based on input and output data sets. The generated rules are examined by checking their validity to use them as T-S type fuzzy rules. Using its excellent advantages in modeling non-linear systems, the T-S type fuzzy model is chosen to perform the fuzzy inference process. A T-S type fuzzy inference system is constructed by an automatic generation of membership functions and rules by the Fuzzy C-Means (FCM) clustering algorithm and the rough set approach, respectively. The generated T-S type rough-fuzzy inference system is then adjusted by the least-squares method and a conjugate gradient descent algorithm towards better performance within a fuzzy system framework. To show the viability of the proposed framework of ARFIS, the performance of ARFIS is compared with other existing approaches in a variety of practical applications; pattern classification, face recognition, and mobile robot navigation. The results are very satisfactory and competitive, and suggest the ARFIS is a suitable new framework for fuzzy inference systems by showing a better system performance with less number of attributes and rules in each application.
173

Retranslation a problem in computing with perceptions /

Martin, Olga J. January 2008 (has links)
Thesis (Ph. D.)--State University of New York at Binghamton, Thomas J. Watson School of Engineering and Applied Science, Department of Systems Science and Industrial Engineering, 2008. / Includes bibliographical references.
174

A Matemática está em tudo: modelagem fuzzy para um problema da indústria e uma proposta de aplicação no Ensino Médio / Mathematics is in everything: fuzzy modeling for an industry problem and an application proposal in High School

Gayer, Fernanda Almeida Marchini [UNESP] 01 December 2017 (has links)
Submitted by FERNANDA ALMEIDA MARCHINI GAYER null (fer_marchini@yahoo.com.br) on 2017-12-12T16:34:52Z No. of bitstreams: 1 dissertacao.pdf: 8726620 bytes, checksum: 66b744fe24afaf15e89574cfd8c23af1 (MD5) / Approved for entry into archive by Adriana Aparecida Puerta null (dripuerta@rc.unesp.br) on 2017-12-12T18:20:47Z (GMT) No. of bitstreams: 1 gayer_fam_me_rcla.pdf: 8697307 bytes, checksum: ef684be2abf1d5c9b37f2d77c9ab5ce8 (MD5) / Made available in DSpace on 2017-12-12T18:20:47Z (GMT). No. of bitstreams: 1 gayer_fam_me_rcla.pdf: 8697307 bytes, checksum: ef684be2abf1d5c9b37f2d77c9ab5ce8 (MD5) Previous issue date: 2017-12-01 / Neste trabalho, apresentamos um estudo introdutório à Teoria de Conjuntos Fuzzy e Lógica Fuzzy, mostrando o seu potencial de aplicação através da análise de um problema numa indústria química e da introdução de alguns conceitos dessa teoria a alunos do Ensino Médio. Quanto ao problema da indústria química, o objetivo é assessorar uma equipe de gestão de manutenção de uma certa indústria química na tomada de decisão quanto ao momento oportuno para realização de intervenção em uma bomba industrial. Esta equipe observou como dificuldade em sua gestão de custos a manutenção preventiva de uma certa bomba de seu processo. Para isso, dados dos processos são analisados e modelados matematicamente utilizando a lógica fuzzy, produzindo um resultado que direciona corretamente os profissionais no momento da tomada de decisão, sobrepondo a manutenção preventiva existente pela manutenção preditiva, baseada em dados do processo. Foi criado um sistema computacional que favorece este processo de forma automática e simplificada, evitando burocracias legais quanto à questão de licenciamento de softwares do mercado, de forma a realizar os cálculos, além de facilitar a incorporação de dados e análises de forma intuitiva, não necessitando de maiores treinamentos para tanto. Por fim, durante o estudo da lógica fuzzy e pesquisas relacionadas, foi detectada a possibilidade de aplicação prática para estudantes do Ensino Médio. Dessa forma, uma aula expositiva com atividades originais foi realizada para apresentar os conjuntos e a lógica fuzzy, mostrando a capacidade dos alunos do Ensino Médio em assimilar os conteúdos já citados. / In this work, we present an introductory study to Fuzzy Set Theory and Fuzzy Logic, showing its potential application through the analysis of a problem in a chemical industry and the introduction of some concepts of this theory to high school students. As for the problem of the chemical industry, the objective is to advise a manufacturing management team of a certain chemical industry in the decision making for an opportune time for an intervention in an industrial pump. This team observed as a difficulty in its cost management a preventive maintenance of a certain pump of its process. For this, the data of the processes are analysed and modelled mathematically using a fuzzy logic, producing a result that correctly directs the professionals at the moment of the decision making, overlapping the existing preventive maintenance, by the base predictive maintenance in process data. It was created a computer system that helps this process in an automatic and simplified way, avoiding legal bureaucracies regarding the licensing of software in the market, in order to perform the calculations, besides facilitating the incorporation of data and analyses in an intuitive way, not requiring of greater training for both. Finally, during the study of fuzzy logic and related research, it was detected as a possibility of practical application for high school students. Thus, an expository class with original activities was performed to present the sets and a fuzzy logic, showing the ability of the high school students to assimilate the referred contents.
175

[en] METHODOLOGY FOR SOLVING FUZZY LINEAR PROGRAMMING PROBLEMS / [pt] METODOLOGIA DE RESOLUÇÃO DE PROBLEMAS DE PROGRAMAÇÃO LINEAR FUZZY

ANDRE ALVES GANDOLPHO 03 April 2006 (has links)
[pt] Esta tese propõe uma metodologia para obter uma solução para problemas de programação linear fuzzy. A metodologia aqui descrita apresenta um conjunto de soluções em que tanto os valores das variáveis quanto o valor ótimo para a função de custo, ou função objetivo, possuem uma faixa de valores possíveis. Assim, é possível fornecer um conjunto de soluções factíveis que atendam a diferentes cenários, além de fornecer ao tomador de decisões uma ferramenta de análise mais útil, permitindo que sejam analisadas outras soluções possíveis antes de se escolher uma solução em particular. O problema é resolvido de forma iterativa, tornando mais simples e de fácil aplicação a metodologia desenvolvida. / [en] This work proposes an approach to obtain a solution to linear fuzzy programming problems. The approach described here presents a solution set in where both the variables values and the cost function optimun value to have an associated membership function. Thus, it is possible to provided not only a feasible solution set applicable to different scenarios but also to supply the decision maker with a more powerful tool for the analysis of other possible solutions. The problem is solved in an interactive way, so that the developed is approach easily applicable and simple to handle
176

Solving multiobjective mathematical programming problems with fixed and fuzzy coefficients

Ruzibiza, Stanislas Sakera 04 1900 (has links)
Many concrete problems, ranging from Portfolio selection to Water resource management, may be cast into a multiobjective programming framework. The simplistic way of superseding blindly conflictual goals by one objective function let no chance to the model but to churn out meaningless outcomes. Hence interest of discussing ways for tackling Multiobjective Programming Problems. More than this, in many real-life situations, uncertainty and imprecision are in the state of affairs. In this dissertation we discuss ways for solving Multiobjective Programming Problems with fixed and fuzzy coefficients. No preference, a priori, a posteriori, interactive and metaheuristic methods are discussed for the deterministic case. As far as the fuzzy case is concerned, two approaches based respectively on possibility measures and on Embedding Theorem for fuzzy numbers are described. A case study is also carried out for the sake of illustration. We end up with some concluding remarks along with lines for further development, in this field. / Operations Research / M. Sc. (Operations Research)
177

Uma aplicação da lógica Fuzzy

Dias, Cristina Helena Bovo Batista [UNESP] 14 October 2010 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:55Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-10-14Bitstream added on 2014-06-13T18:52:59Z : No. of bitstreams: 1 dias_chbb_me_rcla.pdf: 692647 bytes, checksum: 869fdb9734d900054c9edcfce9ca37cc (MD5) / Universidade Estadual Paulista (UNESP) / Desde cedo entramos em contato com as implicações lógicas. O binômio verdadeiro-falso está sempre presente em nossas vidas e nós nos acostumamos a aceitar que as coisas ou são verdadeiras ou são falsas. Divertimo-nos quando alguém nos conta histórias interessantes envolvendo lógica e que terminam em contradições, tais como, por exemplo, a do barbeiro que pode e não pode barbear a si mesmo, ou como a do advogado que consegue ganhar ou perder a mesma causa. Apreciamos mais paradoxos sem nos apercebermos que por trás deles existe toda uma teoria matemática, a chamada lógica fuzzy. Essa dissertação tem por objetivo apresentar um resumo deste teoria, mostrando como ela trata a existência de tais paradoxos e dar detalhes sobre uma visão compacta dos conjuntos fuzzy, a saber, utilizando uma representação geométrica. A análise de alguns resultados sobre tais conjuntos usando esta representação leva a uma justificativa para o estudo da lógica fuzzy, a saber, a diferença entre fuzziness e probabilidade, incluindo uma demonstração de que fuzziness, de fato, existe / Early on we got in touch with the logical implications. The binomial true-false is always present in our lives and we have come to accept that things are either true or false. Have fun when somebody tells interesting stories involving logic and ending with contradictions, such as, for example, the barber who can and can not shave himself, or as the lawyer who can win or lose the same cause. Appreciate more paradoxes without realizing that behind them there is a whole mathematical theory, called fuzzy logic. This thesis aims to present a summary of this theory, showing how it treats the existence of such paradoxes and give details about a compact view of fuzzy sets, namely, using a geometrical representation. The analysis of some results on such sets using this representation leads to a justification for the study of fuzzy logic, namely the difference between fuzziness and probability, including a demonstration that fuzziness in fact, exists
178

Aplicação da teoria dos conjuntos fuzzy em modelos farmacocinéticos multicompartimentais / Application of fuzzy sets theory in multi-compartment pharmacokinetic models

Menegotto, Juliana 06 June 2011 (has links)
Orientador: Laécio Carvalho de Barros / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica / Made available in DSpace on 2018-08-18T10:25:47Z (GMT). No. of bitstreams: 1 Menegotto_Juliana_M.pdf: 2478347 bytes, checksum: d968a14f6bf0c7261143ea6a2e25e99a (MD5) Previous issue date: 2011 / Resumo: Para estudar a concentração do fármaco no organismo utiliza-se modelos farmacocinéticos multicompartimentais que, via de regra, são dados por um sistema de equações diferenciais ordinárias (EDO). Neste trabalho propomos um modelo para descrever a dinâmica da concentração a partir de um sistema baseado em regras fuzzy. Para obter a curva da concentração, utilizamos o método de Takagi-Sugeno-Kang (TSK) e as curvas via TSK e EDO são comparadas. Quando o fármaco é administrado em doses múltiplas, o índice de acúmulo no organismo é avaliado através da razão entre as áreas sob a curva referente à dose dada - após atingir o estado estacionário - e a curva da primeira dose. Simulações são feitas em ambiente Matlab e os índices de acúmulo obtidos em ambas curvas são comparados / Abstract: To study the drug concentration in the organism we use multi-compartment pharmacokinetic models that normally are represented mathematically as a system of ordinary differential equations (ODE). In this work, we propose a model for describing the concentration dynamic from a Fuzzy Rule-Based System (FRBS). In order to obtain the concentration curve, we use the Takagi-Sugeno-Kang (TSK) method and the curves via TSK and ODE are compared. When the drug is administered in multiple doses, the drug accumulation index in the organism is computed from the ratio between the areas under the curve of the dose given - after reaching the steady-state - and the curve of the first dose. Simulations are made in Matlab environment and the accumulation index for both curves are compared / Mestrado / Biomatematica / Mestre em Matemática Aplicada
179

Dispersão de poluente em sistema de reservatorio : modelagem matematica e simulação computacional utilizando-se aproximação numerica e conjuntos fuzzy / Pollutant dispersion in reservoir's systems : mathematical modelling using numerical simulation and fuzzy sets

Poletti, Elaine Cristina Catapani, 1975- 06 October 2009 (has links)
Orientadores: Raul Vinhas Ribeiro, João Frederico da Costa Azevedo Meyer / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-13T15:58:01Z (GMT). No. of bitstreams: 1 Poletti_ElaineCristinaCatapani_D.pdf: 4221797 bytes, checksum: 73aff4b1cd65fe8401a1e01bd20fb19d (MD5) Previous issue date: 2009 / Resumo: O presente trabalho propõe um método para o estudo da dispersão de poluente num sistema de reservatório, via Modelagem Matemática dos fenômenos principais envolvidos na análise deste tipo de situação. Na modelagem, a opção foi pela clássica Equação Diferencial Parcial de Difusão- Advecção com parâmetros fuzzy reunindo, portanto, aspectos determinísticos e a Lógica Fuzzy de modo a incorporar aspectos característicos e relevantes de dispersão efetiva do poluente, seu transporte e degradação. Condições iniciais e de contorno compatíveis com casos conhecidos são propostas, além de aproximações numéricas adequadamente dimensionadas, via Elementos Finitos, na discretização espacial, com um método de tipo Crank-Nicolson na aproximação temporal. Propõe-se, também, um algoritmo que se preste a simulações computacionais eficientes, em ambiente Matlab. Como estudo de caso, utiliza-se a situação evolutiva do reservatório de Salto Grande, represamento do rio Atibaia, um dos mais importantes mananciais de abastecimento público da região, inserido numa importante região do Estado de São Paulo. / Abstract: Current work presents an instrument for dispersion of water's surface pollutant study through Mathematical Modelling and the main phenomenas involved in this type of analysis. For this purpose, we use the Partial Differential Equation of diffusion-advection that incorporates the dispersion accomplish of the pollutant, its transport and decline, with compatible initial and boundering conditions. Numerical approximation well dimensioned are defined and effective computational simulations algorithms, are implemented which considered independent variable, were developed. The independent variable considered can be spatial as well as temporary. As a case study, we use Salto Grande reservoir situation, which is a dike of Atibaia river, one of the most important public water sypply in an important region of São Paulo state. In the descriptive parameters of the problem, the option was the use of fuzzy techniques sets that allow incorporating inherent uncertainties to this situation. / Doutorado / Automação / Doutor em Engenharia Elétrica
180

Algoritmo para resolução do problema de fluxo multiproduto Fuzzy / Algorithm for solving the fuzzy multicommodity flow problem

Verga, Juliana, 1984- 14 August 2018 (has links)
Orientador: Akebo Yamakami / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-14T08:52:58Z (GMT). No. of bitstreams: 1 Verga_Juliana_M.pdf: 625534 bytes, checksum: 396d5b5c1dafff5b2fbb632e185c4a72 (MD5) Previous issue date: 2009 / Resumo: A teoria dos grafos é comumente utilizada na área da engenharia para resolver problemas que podem ser representados na forma de redes. Dentre diversos problemas abordados, o problema de fluxo multiproduto é um dos que também podem ser modelados por grafos. Este trabalho apresenta uma proposta de solução para o problema de fluxo multiproduto fuzzy. O problema foi modelado através de um grafo, cujos nós representam pontos de oferta e demanda de produtos, os quais trafegam pelos arcos da rede. O algoritmo proposto visa encontrar soluções factiveis e boas para o problema de fluxo multiproduto fuzzy em redes com incertezas nos custos e capacidades, contendo múltiplas origens e múltiplos destinos. As incertezas são modeladas por meio da teoria dos conjuntos fuzzy, que tem sido aplicada com sucesso em problemas com incertezas. / Abstract: The graph theory is commonly used in the area of engineering to solve problems that can be represented in the form of nets. Among several problems, the multicommodity flow problem is one that can be modeled by graphs. This work presents an approach for solving the fuzzy multicommodity flow problem. The problem was modeled through a graph whose nodes represent points of supply and demand of commodities, which pass through arcs of the network. Our algorithm aims to find a set of good feasible solutions for the fuzzy multicommodity flow problem in networks with uncertainties in the costs and capacities, containing multiple origins and multiple destinations. The uncertainties are modeled by means of the fuzzy sets theory, which has been successfully applied to problems with uncertainties. / Mestrado / Automação / Mestre em Engenharia Elétrica

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