A Novel Weakest t-Norm based Fuzzy Importance Measure for Fuzzy Fault Tree Analysis of Combustion Engineering Reactor Protection System

2019 ◽  
Vol 27 (06) ◽  
pp. 949-967 ◽  
Author(s):  
Mohit Kumar
Keyword(s):  
Fault Tree ◽  
Fault Tree Analysis ◽  
Protection System ◽  
Importance Measure ◽  
Fuzzy Arithmetic ◽  
Tree Analysis ◽  
Uncertainty Range ◽  
Expert Opinions ◽  
Fuzzy Fault Tree Analysis ◽  
Reactor Protection System

Recently, a new fuzzy fault tree analysis (FFTA) has been developed to propagate and quantify the epistemic uncertainties occurring in qualitative data such as expert opinions or judgments. It is well known that the weakest triangular norm (Tw) based fuzzy arithmetic operations preserve the shape of the fuzzy numbers, provide more exact fuzzy results and effectively reduce uncertainty range. The objective of this paper is to develop a novel Tw-based fuzzy importance measure to identify the critical basic events in FFTA. The proposed approach has been demonstrated by applying it to a case study to identify the critical components of the Group 1 of the U.S. Combustion Engineering Reactor Protection System (CERPS). The obtained results are then compared to the results computed by the existing well-known importance measures of conventional as well as FFTA. The computed results confirm that the proposed Tw -based importance measure is feasible to identify the critical basic events in FFTA in more exact way.

Application of Fuzzy Fault-Tree Analysis to Assess the Reliability of a Protection System for a Switchyard

2008 ◽  
Vol 9 (4) ◽  
Author(s):  
Ying-Yi Hong ◽  
Lun-Hui Lee ◽  
Heng-Hsing Cheng
Keyword(s):  
Power Plant ◽  
Fuzzy Set ◽  
Nuclear Power ◽  
Fault Tree ◽  
Reliability Assessment ◽  
Fault Tree Analysis ◽  
Protection System ◽  
Importance Measure ◽  
Tree Analysis ◽  
Fuzzy Fault Tree Analysis

This paper proposed a method for reliability assessment of the protection system for a switchyard by fault-tree analysis considering uncertainty of unavailability for an element. Unavailability of an element with uncertainty is expressed with the fuzzy set. The fault-tree analysis incorporated with the fuzzy set is employed to conduct the reliability assessment. The importance of elements influencing reliability can be achieved by the Fuzzy Importance Measure. Compared with traditional methods, the fault-tree analysis requires less computation. In this paper, a 345 kV switchyard in the 3rd nuclear power plant in Taiwan serves as an example for illustrating the results of the proposed method.

A Novel Weakest t-norm based Fuzzy Fault Tree Analysis Through Qualitative Data Processing and Its Application in System Reliability Evaluation

2018 ◽  
Vol 29 (1) ◽  
pp. 977-993 ◽  
Author(s):  
Mohit Kumar
Keyword(s):  
System Reliability ◽  
Qualitative Data ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Fuzzy Arithmetic ◽  
Arithmetic Operations ◽  
Uncertainty Interval ◽  
Tree Analysis ◽  
Expert Opinions ◽  
Fuzzy Fault Tree Analysis

Abstract The quantification of the fuzzy fault tree analysis (FFTA) is based on fuzzy arithmetic operations. It is well known that the weakest t-norm (Tw)-based fuzzy arithmetic operations have some advantages. The Tw-based fuzzy arithmetic operations provide fuzzy results with less fuzziness and preserve the shape of fuzzy numbers. The purpose of this study is to develop a Tw-based fuzzy fault tree analysis (TBFFTA) to assess system reliability when only qualitative data such as expert opinions or decisions are available and described in linguistic terms. The developed TBFFTA applies Tw-based fuzzy arithmetic operations to evaluate the lower bound, best estimate, and upper bound top event probability of a system fault tree, where occurrence possibilities of basic events are characterized by triangular fuzzy membership functions. To demonstrate the applicability and feasibility of TBFFTA, a case study has been performed. The computed results have been compared with results analyzed by existing fuzzy approach. The comparative study concludes that TBFFTA reduces fuzzy spreads (uncertainty interval) and provides more exact fuzzy results.

A fuzzy fault tree analysis based risk assessment approach for enterprise resource planning projects

2018 ◽  
Vol 35 (5) ◽  
pp. 1115-1141 ◽  
Author(s):  
Mina Moeinedini ◽  
Sadigh Raissi ◽  
Kaveh Khalili-Damghani
Keyword(s):  
Risk Factors ◽  
Enterprise Resource Planning ◽  
Fault Tree ◽  
Fault Tree Analysis ◽  
Resource Planning ◽  
Successful Implementation ◽  
Tree Analysis ◽  
Content Type ◽  
Cause And Effect ◽  
Fuzzy Fault Tree Analysis

Purpose Enterprise resource planning (ERP) is assumed as a commonly used solution in order to provide an integrated view of core business processes, including product planning, manufacturing cost, delivery, marketing, sales, inventory management, shipping and payment. Selection and implementation of a suitable ERP solution are not assumed a trivial project because of the challenging nature of it, high costs, long-duration of installation and customization, as well as lack of successful benchmarking experiences. During the ERP projects, several risk factors threat the successful implementation of the project. These risk factors usually refer to different phases of the ERP projects including purchasing, pilot implementation, teaching, install, synchronizing, and movement from old systems toward new ones, initiation and utilization. These risk factors have dominant effects on each other. The purpose of this paper is to explore the hybrid reliability-based method is proposed to assess the risk factors of ERP solutions. Design/methodology/approach In this regard, the most important risk factors of ERP solutions are first determined. Then, the interactive relations of these factors are recognized using a graph based method, called interpretive structural modeling. The resultant network of relations between these factors initiates a new viewpoint toward the cause and effect relations among risk factors. Afterwards, a fuzzy fault tree analysis is proposed to calculate Failure Fuzzy Possibility (FFP) for the basic events of the fault tree leading to a quantitative evaluation of risk factors. Findings The whole proposed method is applied in a well-known Iranian foodservice distributor as a case study. The most impressive risk factors are identified, classified and prioritized. Moreover, the cause and effect diagram between the risk factors are identified. So, the ERP leader can plan a low-risk project and increase the chance of success. Originality/value According to the authors’ best knowledge, such approach was not reported before in the literature of ERP risk assessments.

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