Structural Model of Human Reliability with Fuzzy Set Theory

Abstract

The reliability of human is so complicated that its modeling is very difficult. Since the usual probablistic model is only effective for simple physical job, more precise model is required to analyze or to evaluate the human reliability. Because cognition and judgment are now the major task of man. In this paper, many factors on which human reliability depends are aggregated into four parameters, that is, “job load”, “ability”, “stress”, and “concentration allocation”. The relations among these parameters are represented by a combination of structural model and fuzzy set model. This is very useful not only for the logical calculation but also for the expression of uncertainty. Usually these models are considered not adequate for the engineering use, because these are too much conceptual and qualitative. However, we verify, in this paper, the exactness of structure, and identify the characteristics of all the elements concretely through many experiments such as “one person-multi jobs”, “multi persons-one job” and “multi persons-multi jobs”. Therefore, this model is considered to be enough objective and can be utilized conveniently for the analysis of man-machine systems.