Abstract
Fuzzy sets operations should be considered when expert's subjectivity and a natural language are employed in system reliability analysis since natural language expressions of the analysis result are dependent on expert's subjectivity. This paper is concerned with considering fuzzy sets operations from the viewpoint of the fuzzy reliability analysis. In this paper parameterized t-norm and t-conorm are selected as fuzzy sets operations which can cover the range from the least t-norm(a drastic product) through the greatest one (a logical product) and the range from the least t-conorm (a logical sum) through the greatest one(a drastic sum), respectively. From the viewpoint of system reliability analysis the least t-norm and t-conorm mean the most optimistic operation, and the greatest t-norm and t-conorm mean the most pessimistic one. That is, the parameterized fuzzy sets operations can make the most optimistic model through the most pessimistic one for reliability analysis. Finally this paper compares analysis results among three kinds of subjective reliability analyses by an example and discusses the meaning of the parameterized operations from another point of view. The example also shows that parameterized operations reflect expert's subjectivity and intuition about reliability information based on his experience. Subjective reliability analysis is performed by introducing expert's subjectivity to fuzzy sets operations as well as to reliability estimate.
