• Title/Summary/Keyword: fuzzy member function

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The Study of Criteria Weight for Taiwan National Quality Award by Fuzzy Hierarchical Analysis

  • Li, Shao-Chang;Fu, Hsin-Pin
    • International Journal of Quality Innovation
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    • v.7 no.2
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    • pp.83-96
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    • 2006
  • In this paper, fuzzy hierarchical analysis (FHA) is used to explore the process by which the criteria weights of the Taiwan National Quality Award (TNQA) are assigned by TNQA committee members. Each member is allowed to employ fuzzy scales in place of exact scales. Each pairwise comparison of criteria is made through a questionnaire from each TNQA committee member. The membership function of trapezoidal fuzzy numbers is introduced to specify TNQA committee members' intentions. After FHA, the reasonable range of each criterion weight of TNQA is determined. The current criteria weights of TNQA are properly verified.

Optimization of Composite Laminated Plate Using Fuzzy Set Theory (퍼지 이론을 이용한 복합재 적층판의 최적설계)

  • 홍영기;이종호;구만회;우호길
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 1999.11a
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    • pp.63-67
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    • 1999
  • This paper presents the optimization of CFRP laminated rectangular plates using fuzzy theory. In optimization, thickness of CFRP lamina and fiber angle are taken as design variables, and total thickness of the plates is minimized under Tsai-Hill failure criterion. The uncertainties are entered by introducing fuzzy material strengths and then the objective and constraints are represented by a membership function of their own according to the intersection method. Various design results are presented for the CFRP laminated composites plates.

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Design of Self-Tuning Fuzzy Logic Controllers using Genetic Algorithms (유전알고리즘을 이용한 자기동조 퍼지 제어기의 설계)

  • Suh, Jae-Kun;Kim, Tae-Eun;Kwon, Hyuk-Jin;Kim, Lark-Kyo;Nam, Moon-Hyon
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.1374-1376
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    • 1996
  • In this paper We proposed a new method to generate fuzzy logic controllers through genetic algorithm(GA). In designing of fuzzy logic controllers encounters difficulties in the selection of optimized member-ship functions, gains and rule base, which is conventionally achieved by a tedious trial-and-error process. This paper develops genetic algorithms for automatic design of high performance fuzzy logic controllers which can overcome nonlinearities in many engineering control applications. The rule-base is coded in base-7 strings by generated from random function. Which can be presented in discrete fuzzy linguistic value, and using membership function with Gaussian curve. To verify the validity of this fuzzy logic controller it is compared with conventional fuzzy logic controller(FLC) and PID controller.

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Unified Section and Shape Discrete Optimum Design of Planar and Spacial Steel Structures Considering Nonlinear Behavior Using Improved Fuzzy-Genetic Algorithms (개선된 퍼지-유전자알고리즘에 의한 비선형거동을 고려한 평면 및 입체 강구조물의 통합 단면, 형상 이산화 최적설계)

  • Park, Choon Wook;Kang, Moon Myung;Yun, Young Mook
    • Journal of Korean Society of Steel Construction
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    • v.17 no.4 s.77
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    • pp.385-394
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    • 2005
  • In this paper, a discrete optimum design program was developed using the refined fuzzy-genetic algorithms based on the genetic algorithms and the fuzzy theory. The optimum design in this study can perform section and shape optimization simultaneously for planar and spatial steel structures. In this paper, the objective function is the weight of steel structures and the constraints are the design limits defined by the design and buckling strengths, displacements, and thicknesses of the member sections. The design variables are the dimensions and coordinates of the steel sections. Design examples are given to show the applicability of the discrete optimum design using the improved fuzzy-genetic algorithms in this study.

A fuzzy reasonal analysis of human reliability represented as fault tree structure

  • 김정만;이상도;이동춘
    • Journal of the Ergonomics Society of Korea
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    • v.16 no.2
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    • pp.1-14
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    • 1997
  • In conventional probability-based human reliability analysis, the basic human error rates are modified by experts to consider the influences of many factors that affect human reliability. However, these influences are not easily represented quantitatively, because the relation between human reliability and each of these factors in not clear. In this paper, the relation is expressed quantitatively. Furthermore, human reliability is represented by error possibilities proposed by Onisawa, which is a fuzzy set on the interval [0,1]. Fuzzy reasoning is used in this method in order to obtain error possibilities. And, it is supposed that many basic events affected by the above factors are connected to the top event through Fault Tree structure, and an estimate of the top event expressed by a member- ship function is obtained by using the fuzzy measure and fuzzy integral. Finally, a numerical example of human reliability analysis obtained by this method is given.

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Enhanced Fuzzy Binarization Method for Car License Plate Binarization (자동차번호판 이진화를 위한 개선된 퍼지 이진화 방법)

  • Cho, Jae-Hyun
    • The Journal of the Korea institute of electronic communication sciences
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    • v.6 no.2
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    • pp.231-236
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    • 2011
  • The binarization algorithm frequently applies to one part of the preprocessing phase for a variety of image processing techniques such as image recognition and image analysis, etc. So it is important that binarization algorithm is determined by the selection of threshold value for binarization in image processing. The previous algorithms could get the proper threshold value in the case that shows all the difference of brightness between background and object, but if not, they could not get the proper threshold value. In this paper, we propose the efficient fuzzy binarization method which first, segments the brightness range of gray_scale images to 2 intervals to perform car license plate binarization and applies fuzzy member function to each intervals. The experiment for performance evaluation of the proposed binarization algorithm showed that the proposed algorithm generates the more effective threshold value than the previous algorithms in car license plate.

A Study on a Sensitivity Processing Using a Fuzzy Reasoning Rule (퍼지 추론 규칙을 이용한 감성 처리에 관한 연구)

  • Kim, Kwang-Baek;Cho, Jae-Hyun
    • Journal of the Korea Society of Computer and Information
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    • v.12 no.3
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    • pp.1-8
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    • 2007
  • In recent, the issues of sensitivity and psychology of human have received much attention from researchers and practitioners. In this paper. we analyze the information of color and location in order to detect the sensitivity and psychology by means of human vision on color space organization in a presented picture. After this process, we propose a method to determine psychology states through the space organization by using a fuzzy membership function which can be used to analyze direction information for the sensitivity. The proposed method is applied to the psychology states based on the space organization of Alschuler and Hattcick's method and to the space organization of Gunnwald's method. As a result, we present that the proposed method is very similar to a pattern classification of Alschuler and Grunwald.

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Design and Implementation of Fuzzy PID Controller (Fuzzy PID 제어기 설계 및 구현)

  • Shin Wee-Jae
    • Journal of the Institute of Convergence Signal Processing
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    • v.6 no.2
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    • pp.89-94
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    • 2005
  • In this paper, we propose a fuzzy PID controller of new method. There are two problems in absolute digital PID controller. First, much calculation time need for obtain the sum of data at each period. Second, this is problem need much memory because to storage every data at the before period. We use the speed type PID digital controller to improvement such problems. In the propose controller doesn't use without adjustment the crisp output error and we doesn't use nile tables in the fuzzy inference process at the forward stage fuzzifier. We inference output member ship function by using the relation and range of two variable of PID gain parameters. We can obtained desired results through the simulation and a experiment of the hydraulic servo motor control system.

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An Analysis of Fuzzy Survey Data Based on the Maximum Entropy Principle (최대 엔트로피 분포를 이용한 퍼지 관측데이터의 분석법에 관한 연구)

  • 유재휘;유동일
    • Journal of the Korea Society of Computer and Information
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    • v.3 no.2
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    • pp.131-138
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    • 1998
  • In usual statistical data analysis, we describe statistical data by exact values. However, in modem complex and large-scale systems, it is difficult to treat the systems using only exact data. In this paper, we define these data as fuzzy data(ie. Linguistic variable applied to make the member-ship function.) and Propose a new method to get an analysis of fuzzy survey data based on the maximum entropy Principle. Also, we propose a new method of discrimination by measuring distance between a distribution of the stable state and estimated distribution of the present state using the Kullback - Leibler information. Furthermore, we investigate the validity of our method by computer simulations under realistic situations.

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Shape Optimization of Truss Structures with Multiobjective Function by α -Cut Approach (α -절단법에 의한 다목적함수를 갖는 트러스 구조물의 형상최적화)

  • Yang, Chang Yong;Lee, Gyu Won
    • Journal of Korean Society of Steel Construction
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    • v.9 no.3 s.32
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    • pp.457-465
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    • 1997
  • The Shape optimization makes it possible to reduce the weight of structure and cost then member sizing optimization. A vast amount of imprecise information is existed in constraints of the optimum design. It is very difficult and sometimes confusing to describe and to deal with the several criteria which contain fuzzy degrees of relatives importance. This paper proposed weighting strategies in the multiobjective shape optimization of fuzzy structural system by ${\alpha}$-cut approach. The algorithm in this research is numerically tested for 2-bar truss structure. The result show that. the user can choose the one optimum solution in practices as obtaining the optimum solutions according to the ${\alpha}$-cut approach, weight of volume and displacement.

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