• Title/Summary/Keyword: vague set

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Reliability Analysis of Fuzzy Systems With Weighted Components Using Vague Sets (모호집합을 이용한 가중 구성요소를 갖는 퍼지시스템의 신뢰도 분석)

  • Cho, Sang-Yeop;Park, Sa-Joon
    • Journal of KIISE:Software and Applications
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    • v.33 no.11
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    • pp.979-985
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    • 2006
  • In the conventional researches, the reliabilities of the fuzzy system are represented and analyzed by real values between zero and one, fuzzy numbers, intervals of confidence, etc. In this paper, we present a method to represent and analyze the reliabilities of the weighted components of the fuzzy system and the weights reflected on their importance based on vague sets defined in the universe of discourse [0, 1]. The vague set is represented as the interval consisted of the truth-membership functions and the false-membership functions, therefore it can allow the reliabilities and the weights of a fuzzy system to represent in a more flexible manner. The proposed method considers the weights of the weighted components in the fuzzy systems, its reliability analysis is more flexible and effective than the conventional methods.

Robust Parameter Estimation using Fuzzy RANSAC (퍼지 RANSAC을 이용한 강건한 인수 예측)

  • Lee Joong-Jae;Jang Hyo-Jong;Kim Gye-Young;Choi Hyung-il
    • Journal of KIISE:Software and Applications
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    • v.33 no.2
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    • pp.252-266
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    • 2006
  • Many problems in computer vision are mainly based on mathematical models. Their optimal solutions can be found by estimating the parameters of each model. However, provided an input data set is involved outliers which are relative]V larger than normal noises, they lead to incorrect results. RANSAC is a representative robust algorithm which is used to resolve the problem. One major problem with RANSAC is that it needs priori knowledge(i.e. a percentage of outliers) of the distribution of data. To solve this problem, we propose a FRANSAC algorithm which improves the rejection rate of outliers and the accuracy of solutions. This is peformed by categorizing all data into good sample set, bad sample set and vague sample set using a fuzzy classification at each iteration and sampling in only good sample set. In the experimental results, we show that the performance of the proposed algorithm when it is applied to the linear regression and the calculation of a homography.

A Function Evaluation by Fuzzy Set in Value Engineering (가치공학(VE)에 있어 Fuzzy Set을 이용한 기능평가 방법)

  • 이근희;이동형
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.13 no.22
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    • pp.43-50
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    • 1990
  • In conventional function analysis, the function values are evaluated by experts, which are treated as exact values. For many cases, it is often difficult to evaluate the function values of a certain subject because the criteria of evaluation are very vague. This paper presents a new function evaluation method using fuzzy set. The purpose of the method is to minimize the difference among experts by recognizing an intersection point of membership function as a representative value.

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A study on segmentation of medical image using fuzzy set theory (퍼지 이론을 이용한 의료 영상 특징 추출에 관한 연구)

  • 김형석;한영오;박상희
    • 제어로봇시스템학회:학술대회논문집
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    • 1991.10a
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    • pp.741-745
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    • 1991
  • This paper describes a feature extraction in digitized chest X-ray image and CT head Image. There are Extraction, Thresholding, Region G rowing, Split-Merge and Relaxation in feature extraction technique. In this study, Region Growing System was realized and Fuzzy Set Theory was applied in order to extract the vague region which the conventional method has difficulties in extracting. The performance of proposed algorithm was proved by being applied to chest X-ray image and CT head image.

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Risk analysis of offshore terminals in the Caspian Sea

  • Mokhtari, Kambiz;Amanee, Jamshid
    • Ocean Systems Engineering
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    • v.9 no.3
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    • pp.261-285
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    • 2019
  • Nowadays in offshore industry there are emerging hazards with vague property such as act of terrorism, act of war, unforeseen natural disasters such as tsunami, etc. Therefore industry professionals such as offshore energy insurers, safety engineers and risk managers in order to determine the failure rates and frequencies for the potential hazards where there is no data available, they need to use an appropriate method to overcome this difficulty. Furthermore in conventional risk based analysis models such as when using a fault tree analysis, hazards with vague properties are normally waived and ignored. In other word in previous situations only a traditional probability based fault tree analysis could be implemented. To overcome this shortcoming fuzzy set theory is applied to fault tree analysis to combine the known and unknown data in which the pre-combined result will be determined under a fuzzy environment. This has been fulfilled by integration of a generic bow-tie based risk analysis model into the risk assessment phase of the Risk Management (RM) cycles as a backbone of the phase. For this reason Fault Tree Analysis (FTA) and Event Tree Analysis (ETA) are used to analyse one of the significant risk factors associated in offshore terminals. This process will eventually help the insurers and risk managers in marine and offshore industries to investigate the potential hazards more in detail if there is vagueness. For this purpose a case study of offshore terminal while coinciding with the nature of the Caspian Sea was decided to be examined.

Supply Chain Contract Model with Vague Demand Information (모호한 수요정보에서의 공급망 계약 모델)

  • Kim, Gi-Tae;Park, Jun-Cheul
    • The Journal of Information Systems
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    • v.21 no.2
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    • pp.181-196
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    • 2012
  • 본 논문은 고객의 수요정보에 대해 모호한 정보를 가진 공급자와 구매자 사이의 공급망 계약에 관한 것을 다루고 있는 것으로, 고객 수요에 대한 불확실성은 확률적 프로그래밍 모델에서 공식적으로 다루어져왔다. 확률적 프로그램의 한 가지 핵심적인 가정은 널리 알려져 있는바와 같이 수요에 대한 확률분포가 알려져 있다는 것이다. 그럼에도 불구하고 만약 수요에 대한 정보가 모호하거나 정확하지 않다면 수요에 대한 확률분포가 정확하지 않다는 점이다. 이런 상황에서 퍼지 이론은 수요정보를 나타내는데 유용하다고 할수 있다. 본 논문은 퍼지 랜덤수요변수들을 분산시스템의 공급망 계약에서 다루고 있다. 이 계약은 구매자의 주문량을 조정하는 옵션을 이용한다. 본 연구는 퍼지 랜덤 변수들을 GMIR(Graded Mean Integration Representation)을 이용하여, 알고리즘을 통해 구현함으로써 실증적 결과 값을 제시하고 미래 연구의 확장 가능성을 제시하고 있다.

Development of a Microscopic Gap Measuring Algorithm with a Fuzzy-RANSAC (퍼지란삭을 이용한 미소 거리 측정 알고리즘 개발)

  • Kim, Jae-Hoon;Park, Seung-Kyu;Yoon, Tae-Sung
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1545-1546
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    • 2008
  • In this study, an image processing method with FRANSAC(Fuzzy RANSAC) is presented and discussed for the development of a microscopic gap measuring algorithm. Many problems in edge detection processing are mainly occurred by the illumination system. A serious problem is that the edge set of gap could include the error elements that have relatively larger error than normal. This problem leads to a incorrect measurement of gap. We present a gap measuring algorithm using FRANSAC[1] that is a representative robust estimation algorithm. FRANSAC is peformed by first categorizing all data into good sample set, bad sample set and vague sample set using a fuzzy classification and then sampling in only good sample set. Experimental results show that the presented gap measuring algorithm gives a higher accurate value of gap especially for the more noisy image data.

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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.

Robust Estimation of Camera Motion using Fuzzy Classification Method (퍼지 분류기법을 이용한 강건한 카메라 동작 추정)

  • Lee, Joong-Jae;Kim, Gye-Young;Choi, Hyung-Il
    • The KIPS Transactions:PartB
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    • v.13B no.7 s.110
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    • pp.671-678
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    • 2006
  • In this paper, we propose a method for robustly estimating camera motion using fuzzy classification from the correspondences between two images. We use a RANSAC(Random Sample Consensus) algorithm to obtain accurate camera motion estimates in the presence of outliers. The drawback of RANSAC is that its performance depends on a prior knowledge of the outlier ratio. To resolve this problem the proposed method classifies samples into three classes(good sample set, bad sample set and vague sample set) using fuzzy classification. It then improves classification accuracy omitting outliers by iteratively sampling in only good sample set. The experimental results show that the proposed approach is very effective for computing a homography.