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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.
1

Coimplicações Fuzzy Valoradas Intervalarmente / FUZZY COIMPLICATION INTERVAL VALUED

Reis, Gesner Antônio Azevedo dos 21 December 2010 (has links)
Made available in DSpace on 2016-03-22T17:26:43Z (GMT). No. of bitstreams: 1 Gesner.pdf: 787824 bytes, checksum: 39876589a5891eb7dea64c7a471b8166 (MD5) Previous issue date: 2010-12-21 / Traditional digital logic deals with variables assuming only two possible states: false and true. But for a large number of real world modeling, we want intermediary values. The concept of duality, stating that something can and must coexist with its opposite, makes the fuzzy logic seem natural, even inevitable. Thus, the fuzzy logic introduces the ability to infer conclusions and generates responses based on vague information, which is also ambiguous and qualitatively incomplete and inaccurate. In this context, the way of thinking of fuzzy-based systems is similar to humans, representing the expressions of natural language in a very simple and intuitive way, leading to the construction of systems easy to understand and to maintain. Other important area of research based on mathematical models for the treatment of uncertainty considers interval mathematics, which has been applied in the representation of inaccurate data. In interval mathematics, the principle of correctness is the assurance that in the computation of an algorithm, the interval output contains all possible outcomes corresponding to punctual data for an interval input. In addition, the optimality principle, determines that the interval output is the smallest possible one satisfying accuracy. Thus, the correctness is the minimum condition while the optimality is the ideal condition to be satisfied by interval computations. Based on these statements, intervals can be used to represent unknown values and to represent continuous values in scientific computing algorithms. The aims of interval valued fuzzy logic are to consider the interval fuzzy constructions as fuzzy constructors which are correct and to analyze criteria to ensure optimality. The extension of the interval connectives of fuzzy logic in this work is based on the canonical interval representation of real functions and in this case, restricted to the unit interval [0; 1] of the real line. Such representation always returns the smallest interval containing the image of the function. Considering concepts and foundations of both approaches, fuzzy logic and interval mathematics, this work studies the operators defined as coimplications. They are characterized as dual structure of the fuzzy implications. Moreover, it seeks to introduce the extension of the interval fuzzy coimplications, and analyses the satisfaction of properties similar to the respective classes of fuzzy coimplications. In particular, we show that valued interval fuzzy coimplications are representations of fuzzy coimplications satisfying these two principles. This Work also analise the dual structure of interval conjugate fuzzy implications, which are obtained from interval automorphisms / A l´ogica digital tradicional lida com vari´aveis assumindo apenas dois poss´ıveis estados: falso e verdadeiro. Mas para grande n´umero de modelagens do mundo real desejamos valores intermedi´arios. O conceito de dualidade, estabelecendo que algo pode e deve coexistir com o seu oposto, faz a l´ogica difusa parecer natural, at´e mesmo inevit´avel. Assim, a l´ogica fuzzy introduz a habilidade em inferir conclus oes e gerar respostas baseadas em informac¸ oes vagas, amb´ıguas e qualitativamente incompletas e imprecisas. Neste contexto, os sistemas de base fuzzy apresentam uma forma de raciocinar semelhante aos humanos, representando as express oes da linguagem natural de maneira muito simples e intuitiva, levando `a construc¸ ao de sistemas compreens´ıveis e de f´acil manutenc¸ ao. Outra importante ´area de pesquisa baseada em modelos matem´aticos para tratamento da incerteza considera a matem´atica intervalar, a qual vem sendo aplicada na representac¸ ao de dados inexatos. Em matem´atica intervalar, o princ´ıpio da corretude consiste na garantia de que, na computac¸ ao de um algoritmo, a sa´ıda intervalar cont´em todos os poss´ıveis resultados pontuais correspondentes aos dados pontuais referentes `a entrada intervalar. E, o princ´ıpio da optimalidade, determina que a sa´ıda intervalar seja a menor poss´ıvel satisfazendo a corretude. Assim, a corretude ´e a condic¸ ao m´ınima enquanto que a optimalidade ´e a condic¸ ao ideal a ser satisfeita por uma computac¸ ao intervalar. Com base nestes crit´erios, os intervalos podem ser aplicados para representar valores desconhecidos e para representar valores cont´ınuos em algoritmos da Computac¸ ao Cient´ıfica. O principal objetivo da l´ogica fuzzy valorada intervalarmente ´e considerar as construc¸ oes fuzzy intervalares como construc¸ oes fuzzy que s ao corretas e analisar crit´erios que garantam optimalidade. A extens ao intervalar dos conectivos da l´ogica fuzzy em estudo neste trabalho est´a baseada na representac¸ ao intervalar can onica de func¸ oes reais e, neste caso, restrita ao intervalo unit´ario [0; 1] da reta real, que sempre retorna o menor intervalo contendo a imagem da func¸ ao. Consideram-se conceitos e fundamentos de ambas abordagens, da l´ogica fuzzy e da matem´atica intervalar, para estudar os operadores definidos como coimplicac¸ oes, caracterizados como estrutura dual das implicac¸ oes fuzzy, buscando introduzir a extens ao intervalar das coimplicac¸ oes fuzzy, analisando a satisfac¸ ao de propriedades an´alogas `as respectivas classes de coimplicac¸ oes fuzzy valoradas pontualmente. Em particular, mostra-se que coimplicac¸ oes fuzzy valoradas intervalarmente s ao representac¸ oes de coimplicac¸ oes fuzzy satisfazendo estes dois princ´ıpios. O trabalho tamb´em contempla uma an´alise da estrutura dual das conjugadas de implicac¸ oes valoradas intervalarmente, as quais s ao obtidas por ac¸ ao de automorfismos intervalares

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