• Title/Summary/Keyword: Fuzzy systems

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INTUITIONISTIC FUZZY WEAK CONGRUENCES ON A SEMIRING

  • Hur, Kul;Jang, Su-Youn;Lee, Keon-Chang
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.6 no.4
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    • pp.321-330
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    • 2006
  • We introduce the concept of intuitionistic fuzzy weak congruence on a semiring and obtain the relation between intuitionistic fuzzy weak congruence and intuitionistic fuzzy ideal of a semiring. Also we define and investigate intuitionistic fuzzy quotient semiring of a semiring over an intuitionistic fuzzy ideal or over an intuitionistic fuzzy weak congruence.

Fuzzy Almost Strongly (r, s)-Semicontinuous Mappings

  • Lee, Seok-Jong;Kim, Jin-Tae
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.12 no.2
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    • pp.149-153
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    • 2012
  • In this paper, we introduce the concept of fuzzy almost strongly (r, s)-semicontinuous mappings on intuitionistic fuzzy topological spaces in $\check{S}$ostak's sense. The relationships among fuzzy strongly (r, s)-semicontinuous, fuzzy almost (r, s)-continuous, fuzzy almost (r, s)-semicontinuous, and fuzzy almost strongly (r, s)-semicontinuous mappings are discussed. The characterization for the fuzzy almost strongly (r, s)-semicontinuous mappings is obtained.

Fuzzy Hyperpsaces : Fuzzy Compactness

  • K.Hur;C.J. Rhee;J. H. Ryou
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.05a
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    • pp.41-44
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    • 2003
  • First, we investigate some properties of fuzzy compactness. Second, we introduce the concept of fuzzy local compactness in fuzzy topological space and study some of its properties. Finally, we investigate some relations between F-compactness in fuzzy topological spaces and one in fuzzy hyperspaces.

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A Suggestion of Nonlinear Fuzzy PID Controller to Improve Transient Responses of Nonlinear or Uncertain Systems

  • Kim, Jong-Hwa
    • Journal of the Korean Institute of Intelligent Systems
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    • v.5 no.4
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    • pp.87-100
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    • 1995
  • In order to control systems which contain nonlinearities of uncertainties, control strategies must deal with the effects of them. Since most of control methods based on system mathematical models have been mainly developed focused on stability robustness against nonlinearities or uncertainties under the assumption that controlled systems are linear time invariant, they have certain amount of limitations to smartly improve the transient responses of systems disturbed by nonlinearities or uncertainties. In this paper, a nonlinear fuzzy PID control method is suggested which can stably improve the transient responses of systems disturbed by nonlinearities, as well as systems whose mathematical characteristics are not perfectly known. Although the derivation process is based on the design process similar to general fuzzy logic controller, resultant control law has analytical forms with time varying PID gains rather than linguistic forms, so that implementation using common-used versatile microprocessors cna be achieved easily and effectively in real-time control aspect.

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Fault Location Using Neuro-Fuzzy for the Line-to-Ground Fault in Combined Transmission Lines with Underground Power Cables (뉴로-퍼지를 이용한 혼합송전선로에서의 1선지락 고장시 고장점 추정)

  • 김경호;이종범;정영호
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.10
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    • pp.602-609
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    • 2003
  • This paper describes the fault location calculation using neuro-fuzzy systems in combined transmission lines with underground power cables. Neuro-fuzzy systems used in this paper are composed of two parts for fault section and fault location. First, neuro-fuzzy system discriminates the fault section between overhead and underground with normalized detail coefficient obtained by wavelet transform. Normalized detail coefficients of voltage and current in half cycle information are used for the inputs of neuro-fuzzy system. As the result of neuro-fuzzy system for fault section, impedance of selected fault section is calculated and it is used as the inputs of the neuro-fuzzy systems for fault location. Neuro-fuzzy systems for fault location also consist of two parts. One calculates the fault location of overhead, and the other does for underground. Fault section is completely classified and neuro-fuzzy system for fault location calculates the distance from the relaying point. Neuro-fuzzy systems proposed in this paper shows the excellent results of fault section and fault location.

Tuning Fuzzy Rules Based on Additive-Type Fuzzy System Models

  • Shi, Yan;Mizumoto, Masaharu
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 1998.06a
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    • pp.387-390
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    • 1998
  • In this paper, we suggested a neuro-fuzzy learning algorithm for tuning fuzzy rules, in which a fuzzy system model is of additive-type. Using the method, it is possible to reduce the computation size, since performing the fuzzy inference and tuning the fuzzy rules of each fuzzy subsystem model are independent. Moreover, the efficiency of suggested method is shown by means of a numerical example.

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Evaluation of certainty and uncertainty for Intuitionistic Fuzzy Sets

  • Wang, Hong-Mei;Lee, Sang-Hyuk
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.10 no.4
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    • pp.259-262
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    • 2010
  • Study about fuzzy entropy and similarity measure on intuitionistic fuzzy sets (IFSs) were proposed, and analyzed. Unlike fuzzy set, IFSs contains uncertainty named hesistancy, which is contained in fuzzy membership function itself. Hence, designing fuzzy entropy is not easy because of ununified entropy definition. By considering different fuzzy entropy definitions, fuzzy entropy is designed and discussed their relation. Similarity measure was also presented and verified its usefulness to evaluate degree of similarity.

Fuzzy r-Pre-semineighborhoods and Fuzzy r-Pre-semicontinuous Maps

  • Lee, Seok-Jong;Eoum, Youn-Suk
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.1 no.1
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    • pp.62-68
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    • 2001
  • In this paper, we introduce the concepts of fuzzy r-pre-semiopen and r-pre-semiclosed sets. With them we define fuzzy r-pre-semiinterior and r-pre-semiclosure. We also introduce and investigate the properties of a fuzzy r-pre-semicontinuous map, a fuzzy r-pre-semiopen map and a fuzzy r-pre-semiclosed map. These concepts are generalizations of the Bai Shi-Zhongs fuzzy pre-semicontinuity.

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Fuzzy Test for the Fuzzy Regression Coefficient (퍼지회귀계수에 관한 퍼지검정)

  • 강만기;정지영;최규탁
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2001.05a
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    • pp.29-33
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    • 2001
  • We propose fuzzy least-squares regression analysis by few error term data and test the slop by fuzzy hypotheses membership function for fuzzy number data with agreement index. Finding the agreement index by area for fuzzy hypotheses membership function and membership function of confidence interval, we obtain the results to acceptance or reject for the test of fuzzy hypotheses.

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On Fuzzy α-Weakly r-Continuous Mappings

  • Min, Won-Keun
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.9 no.3
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    • pp.228-231
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    • 2009
  • In this paper, we introduce the concept of fuzzy $\alpha$-weakly r-continuous mapping on a fuzzy topological space and investigate some properties of such a mapping and the relationships among fuzzy $\alpha$-weakly r-continuity, fuzzy r-continuity and fuzzy weakly r-continuity.