Unavailability evaluation of system by using Bayesian Network and fuzzy logic

In this article, the analysis of the problem of imprecision is treated in the evaluation of the unavailability of the Safety Instrumented Systems (SIS). The analysis rests on an approach by the Bayesian Networks; the imprecision on the characteristic parameters is modeled by an approach based on a fuzzy system of inference. The model suggested is applied to a SIS to evaluate the impact of the imprecision to the unavailability of the safety systems.