구 퍼지집합에 기반을 둔 퍼지시스템 신뢰도 분석

김동혁,조상엽 한국지식정보기술학회 2023 한국지식정보기술학회 논문지 Vol.18 No.6

Since the fuzzy set proposed by Zadeh has been applied to evaluate the reliability of fuzzy systems, various fuzzy sets have been used to analyze the reliability of fuzzy systems. Expressing the reliability of the system as an accurate value is a difficult problem due to the ambiguity of the data. It is possible to overcome these problems with fuzzy sets. Therefore, fuzzy sets provide a way to appropriately express the reliability of inaccurate data that occurs in the real world. In fuzzy sets, reliability is expressed as a real number, which is the degree of membership. In intuitionistic fuzzy sets, reliability is expressed as an interval using positive and negative membership degrees. In the Pythagorean fuzzy sets, reliability is expressed by expressing the positive and negative membership degrees as squares, respectively. Therefore, it is possible to solve the problem where the sum of the positive and negative membership degrees exceeds 1. In picture fuzzy sets, reliability is expressed based on positive membership, neutral membership, and negative membership. Since the picture fuzzy set uses a neutral degree of membership, it becomes possible to express uncertainty that is neither positive nor negative. In the spherical fuzzy sets, reliability is expressed by expressing the positive membership degree, neutral membership degree, and negative membership degree as squares, respectively. Therefore, it is possible to solve the problem in which the sum of the positive membership degree, the neutral membership degree, and the negative membership degree exceeds 1. And since the spherical fuzzy set can express all the properties of conventional fuzzy sets, it can be used in various environments. Therefore, it becomes possible to express the reliability of fuzzy systems in various environments using sphere fuzzy sets, thereby enabling more flexible reliability analysis.

타입-2 퍼지집합을 이용한 퍼지 공학시스템의 신뢰도 분석

전병찬,조상엽 한국지식정보기술학회 2022 한국지식정보기술학회 논문지 Vol.17 No.5

공학시스템의 설계에서 시스템의 신뢰도를 보장하는 것은 중요한 주제 중에 하나이다. 공학시스템의 신뢰도는 하위시스템의 순차 또는 병렬 구성요소를 반영하여 각각 방법으로 신뢰도를 계산한 후, 전체 공학시스템의 신뢰도를 평가하게 되면 시스템의 신뢰도를 계산하는 것이 가능하게 된다. 본 연구에서는 타입-2 퍼지집합을 이용하여 공학시스템의 신뢰도를 분석하는 방법을 제안한다. 타입-2 퍼지집합은 퍼지집합을 삼차원적으로 표현하므로 기존의 퍼지집합-퍼지집합, 직관 퍼지집합, 모호집합, 수준 (λ,1) 구간값 퍼지집합, 뉴트로소픽 집합, 팔각형 직관 퍼지집합, 다각형 타입-1 퍼지집합 등-보다 더 다양한 형태의 퍼지집합을 표현하는 것이 가능하다. 또한 소속값을 단위 구간 [0, 1] 사이의 임의의 값을 가질 수 있는 이차 소속값으로 표현하므로 신뢰도를 하나의 실수로 표현하는 타입-1 퍼지집합보다 소속값을 더 유연하게 표현하는 것이 가능하다. 그리고 신뢰도공학에서 제시하는 가능성척도 기반의 두 가지 가정을 수용하므로 신뢰도를 평가하는데 타입-2 퍼지집합을 사용하는 이론적 근거를 가지고 있다. 타입-2 퍼지집합을 이용하여 신뢰도를 계산하는 방법은 퍼지 공학시스템, 퍼지 의사결정시스템, 퍼지 신뢰도공학, 퍼지 추론시스템 등에 적용하는 것이 가능하다. The guarantee for the reliability of systems in the design of engineering systems is one of the important issues. The reliability of the engineering systems can be analyzed by evaluating the reliability of the entire engineering systems after calculating the reliability in each method by reflecting the sequential or parallel components of the subsystems. In this study, we propose the method for analyzing the reliability of the engineering systems using type-2 fuzzy sets. Since type-2 fuzzy sets represent the fuzzy set as the three dimensional, it is possible to represent more various shape of fuzzy sets than the conventional fuzzy sets-fuzzy sets, intuitionistic fuzzy sets, vague sets, level (λ,1) interval-valued fuzzy sets, neutrosophic sets, octagonal intuitionistic fuzzy sets, polygonal type-1 fuzzy sets, etc-. In addition, since the degree of membership is represented as the secondary grade which may take any value from unit interval [0, 1], it becomes possible to express the degree of membership more flexible than the type-1 fuzzy sets that represent the reliability as one real number. And then it accepts the two assumptions based on the possibility measure of fuzzy reliability engineering, it has theoretical bases for using type-2 fuzzy sets to evaluate reliability. The proposed method of obtaining the reliability based type-2 fuzzy sets can be applied to fuzzy engineering systems, fuzzy decision making systems, fuzzy reliability engineering, fuzzy inference systems, etc.

다각형 구간 타입-2 퍼지집합을 이용한 퍼지 공학시스템의 신뢰도 분석

조상엽 한국지식정보기술학회 2022 한국지식정보기술학회 논문지 Vol.17 No.5

공학시스템을 운영하는 경우 사용자의 실수, 입력 오류, 입력 데이터의 불확실성 등에 의해 신뢰도가 떨어지는 출력을 생산하게 된다. 이러한 문제를 제어하기 위한 방법은 시스템의 구성요소의 신뢰도를 반영하여 전체 공학시스템이 신뢰도를 출력에 반영하는 것이다. 본 논문에서는 공학시스템의 신뢰도를 평가하기 위하여 퍼지집합 이론을 기반으로 신뢰도를 계산하는 방법을 사용한다. 퍼지집합의 종류에는 소속값을 실수로 표현하는 전통적인 퍼지집합, 과 소속값을 구간으로 표현하는 직관퍼지집합, 구간으로 표현되는 소속값의 상한은 1로 고정하고 하한을 λ로 표현하는 수준 (λ,1) 구간값 퍼지집합, 불확정성을 표현할 수 있는 뉴트로소픽 집합, 다양한 퍼지집합을 표현하기 위한 다각형 타입-1 퍼지집합, 전통적인 퍼지지합의 소속값을 소속함수로 표현하는 타입-2퍼지집합 등이 제안되었다. 본 연구에서 우리는 다각형 구간 타입-2 퍼지집합을 이용하여 공학시스템의 신뢰도를 평가하는 방법을 제안한다. 구간 타입-2 퍼지집합은 이차 소속값이 모두 1과 같은 값을 가진다. 다각형 구간 타입-2 퍼지집합은 하한 소속함수와 상한 소속함수가 다각형으로 표현된다. 그러므로 기존의 퍼지집합들 보다 더 다양한 모양의 퍼지집합을 표현하는 것이 가능하게 된다. In the case of operating the engineering systems, the low reliable output of the systems may produced due to users error, input error, uncertainty of input data, etc. The way to overcome these problem is that the reliability of the entire engineering systems is reflected in the output by reflecting the reliability of the components of the systems. In this paper, in order to analyze the reliability of the engineering systems, we use the fuzzy set theory for calculating the reliability. The fuzzy sets have various types of sets such as the conventional fuzzy sets that represents the degree of membership as a real number, the intuitive fuzzy sets that expresses the degree of membership as an interval, the level (λ,1) interval valued fuzzy set that describe the upper bound of interval is fixed at 1 and the lower bound represent λ, the neutrosophic sets that can express the indeterminacy, the polygonal type-1 fuzzy sets that can describe various shape of conventional fuzzy sets, the type-2 fuzzy sets that represent the membership degree of conventional fuzzy sets as the membership function. In this study, we propose a method to analysis the reliability of engineering systems using polygonal interval type-2 fuzzy sets. In the interval type-2 fuzzy sets, secondary grades are all equal to 1. In the polygon interval type-2 fuzzy sets, the lower membership function and the upper membership function are expressed as polygons. Therefore, it becomes possible to represent fuzzy sets of more various shapes than the conventional fuzzy sets.

구간값 피타고라스 퍼지집합에 기반을 둔 퍼지 공학시스템 신뢰도 분석

조상엽 한국지식정보기술학회 2023 한국지식정보기술학회 논문지 Vol.18 No.6

The reliability of the engineering systems operating in the real world has an important meaning. Such reliability becomes difficult to obtain an accurate reliability due to inaccurate data, wrong manipulation, etc. To solve this problems, the fuzzy sets have been used. There are several fuzzy sets used to calculate reliability. In the fuzzy sets, it is expressed as a real number , which is the belongingness degree of the fuzzy set. ∈ . In the intuitionistic fuzzy sets, the belongingness degree of the fuzzy set is expressed as , and the non-belongingness degree is described as respectively. , ∈ , 0 ≤ + ≤ 1. In the interval-valued intuitionistic fuzzy sets, the belongingness degree of the fuzzy set is expressed as [, ] and the non-belongingness degree is represented as [, ] respectively. , , , ∈ , + ≤ 1, 0 ≤ + ≤ 1, 0 ≤ + ≤ 1. In the Pythagorean fuzzy sets, the belongingness degree in a fuzzy set is expressed as , and the non-belongingness degree is expressed as . , ∈ , 0 ≤ + ≤ 1. In this paper, we propose a method for calculating the reliability of the fuzzy engineering systems using the interval-valued Pythagorean fuzzy sets that can express flexibility in the Pythagorean fuzzy sets.

수준 (λ, ρ) 직관 퍼지 집합을 이용한 시스템의 신뢰도 분석

조상엽 한국지식정보기술학회 2017 한국지식정보기술학회 논문지 Vol.12 No.5

In this paper we propose a method to evaluate the reliability of systems using the level intuitionistic fuzzy sets. There are various studies using fuzzy sets, interval-valued fuzzy sets, L-R fuzzy numbers, level λ triangular fuzzy sets, level interval-valued fuzzy numbers, and intuitionistic fuzzy sets as methods to provide the theoretical basis of the analysis method for system reliability. The fuzzy sets represnt the degree of membership as a real number between zero and one. In the interval-valued fuzzy sets, the degree of membership represent the interval. Therefore, it is possible to solve the problem that the degree of membership for the fuzzy sets is uncertain. The L-R fuzzy numbers can be adjusted differently to the left-right slope of the membership functions. Therefore, we can represent more various fuzzy numbers. Level λ triangular fuzzy sets can adjust the magnitude of the degree of membership using λ. If λ = 1, it becomes level λ fuzzy numbers. In the level interval-valued fuzzy numbers it is possible to adjust the magnitude of the minimum degree of membership by using λ. The intuitionistic fuzzy sets can represent beliefs using a truth-membership function supporting evidence and a falsity-membership function contrary to evidence. In the level intuitionistic fuzzy sets used in this paper, it is possible to adjust the minimum degree of membership value of the falsity-membership function and the maximum degree of the truth-membership function by using λ and ρ, respectively. Therefore, it becomes possible to express various intuitive fuzzy sets.

수준 (λ, 1) 사다리꼴 구간값 뉴트로소픽 집합을 이용한 시스템의 신뢰도 분석

조상엽 한국지식정보기술학회 2018 한국지식정보기술학회 논문지 Vol.13 No.5

There are various types of fuzzy sets used to evaluate the reliability of the systems. In the fuzzy sets, the membership value is represented as a real number and the reliabilities are expressed by using it. In the interval valued fuzzy sets, the degree of membership is represented as an interval [, ] which is used to describe the reliabilities. In the vague sets, the degree of membership is represented as [, ] and it is used to express the reliabilities. In the interval valued vague sets, the membership degree is represented as a [, , , ] and it is used to express the reliabilities. In the level (λ, 1) interval valued fuzzy sets, the membership degree is represented as a interval [λ, 1] which is used to describe the reliabilities. In order to represent the degree of membership in the interval valued neutrosophic sets, (, , ) is used and the reliabilities are expressed by using it. In this paper we propose a level (λ, 1) interval valued neutrosophic sets that can express the merits of the level (λ, 1) interval valued fuzzy sets and the interval valued neutrosophic sets. In the level (λ, 1) interval valued neutrosophic sets its provide flexibility to adjust the size of the minimum membership value using λ and also enable to express the indeterminacy by using the indeterminacy membership value of the neutrosophic sets. Therefore the level (λ, 1) interval valued neutrosophic sets become more flexible and rigorous to describe the reliabilities than the other methods.

케이슨식방파제의 퍼지 신뢰성 기반 LCC 및 통합VE 분석

오은지(Oh Eun-Ji),손영현(Son Young-Hyun),박주원(Park Ju-Won),최미라(Choi Mi-Ra),이증빈(Lee Cheung-Bin) 한국구조물진단유지관리학회 2006 한국구조물진단학회 학술발표회논문집 Vol.10 No.1

Deterioration performance of caisson type breakwaters may be affected by various factors such as types and projects, construction methods, procedure, climate, and site conditions etc. Presently, in design VE(Value Engineering) and LCC(life cycle cost), designers have still often uncertain of their responsibilities, lack information and training of deterioration. Therefore, designers are still failing to exploit the potential that they are able to eliminate and reduce risks on site. in this study, the concepts of integrated VE analysis assessment is introduced in order to achieve ""Design-for-Deterioration performance""in design VE phase. For this purpose, a framework for fuzzy reliability -based LCC and value analysis model using fuzzy logic-based approach for breakwaters projects is suggested. It is anticipated that the methodology proposed in this paper can also be utilized in the design and maintenance phase of other facilities where decision making is made for the fuzzy reliability-based life cycle cost and value analysis.

케이슨식방파제의 퍼지 신뢰성 기반 LCC 및 통합VE 분석

오은지 ( Oh Eun-ji ),손영현 ( Son Young-hyun ),박주원 ( Park Ju-won ),최미라 ( Choi Mi-ra ),이증빈 ( Lee Cheung-bin ) 한국구조물진단유지관리공학회 2006 한국구조물진단유지관리공학회 학술발표대회 논문집 Vol.10 No.1

Deterioration performance of caisson type breakwaters may be affected by various factors such as types and projects, construction methods, procedure, climate, and site conditions etc. Presently, in design VEX Value Engineering) and LCC (life cycle cost), designers have still often uncertain of their responsibilities, lack information and training of deterioration. Therefore, designers are still failing to exploit the potential that they are able to eliminate and reduce risks on site, in this study, the concepts of integrated VE analysis assessment is introduced in order to achieve “Design-for-Deterioration performance” in design VE phase. For this purpose, a framework for fuzzy reliability -based LCC and value analysis model using fuzzy logic-based approach for breakwaters projects is suggested. It is anticipated that the methodology proposed in this paper can also be utilized in the design and maintenance phase of other facilities where decision making is made for the fuzzy reliability-based life cycle cost and value analysis.

New method for dependence assessment in human reliability analysis based on linguistic hesitant fuzzy information

Zhang, Ling,Zhu, Yu-Jie,Hou, Lin-Xiu,Liu, Hu-Chen Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.11

Human reliability analysis (HRA) is a proactive approach to model and evaluate human systematic errors, and has been extensively applied in various complicated systems. Dependence assessment among human errors plays a key role in the HRA, which relies heavily on the knowledge and experience of experts in real-world cases. Moreover, there are ofthen different types of uncertainty when experts use linguistic labels to evaluate the dependencies between human failure events. In this context, this paper aims to develop a new method based on linguistic hesitant fuzzy sets and the technique for human error rate prediction (THERP) technique to manage the dependence in HRA. This method handles the linguistic assessments given by experts according to the linguistic hesitant fuzzy sets, determines the weights of influential factors by an extended best-worst method, and confirms the degree of dependence between successive actions based on the THERP method. Finally, the effectiveness and practicality of the presented linguistic hesitant fuzzy THERP method are demonstrated through an empirical healthcare dependence analysis.

A novel T-S fuzzy fault tree hybrid method for failure risk and multi-state reliability analysis of integrated production manufacturing system based on CPS

Xiaoping Bai,Xiangyun Gu 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.4

The integrated production manufacturing system based on cyber-physical system (CPS) is a complex production system that integrates perception, calculation, and control. Studying the multi-state reliability of integrated production manufacturing system based on CPS has the certain theory and practical significance. This paper presented a novel T-S fuzzy fault tree hybrid method to analyse its failure risk and reliability. Firstly, the fuzzy set theory was used to determine the state probability of the bottom event. Then the state probability and fuzzy possibility of the system were determined according to the state probability and actual state of the bottom event, respectively. Finally, the weak reliability links under different failure states of the system were determined according to the importance and sensitivity analysis. The application case analysis shows that the presented method is consistent with the field situation and can provide reference for failure risk and reliability analysis in integrated production manufacturing system based on CPS.