AN APPLICATION OF FUZZY CONCEPTS TO MODELING OF RELIABILITY-ANALYSIS

This paper emphasizes the necessity of applying fuzzy concepts to the reliability analysis from several points of view. This paper also reviews a fuzzy model of the reliability analysis. The present model contains the following considerations. 1. (1) The failure possibility and the error possibility. These possibilities express equipment reliability and human reliability in place of the failure rate and the error rate, respectively. They are derived from the estimation of the failure rate or the error rate and many factors affecting reliability, and are regarded as the same measure from the viewpoint of the reliability analysis. 2. (2) Operations of the failure and the error possibilities in order to analyze system reliability. 3. (3) The operation of dependence. Two kinds of dependence are considered. 4. (4) The operation of fuzziness which is contained in the qualitative expression. 5. (5) Evaluation of the failure possibility and the error possibility which are obtained by the analysis. 6. (6) Sensitivity analysis. The extent to which each factor influences system reliability is evaluated. As an example an operator's task in a plant is analyzed including equipment reliability. © 1990.