Reliability analysis for non-monotonic system failure functions

摘要

Integrated hardware and software systems are becoming more complex and thus maing safety and reliability analysis mor difficult to perform correctly and efficiently. One way tried at Saab AB is to utilize so-called formal methods, performed in a framework facilitated by a computer tool, NP-Tools. In this paper the problem of deciding cut sets for non-monotonic failure functions is illustrated and a general method for determining prime implicants, the equivalence to cut sets, applicable for both monotonic and non-monotonic failure functions, is presented. Given a general functional description of the system, the prime implicants are determined without explicitly constructing a fault tree. Also, the system description can include the functionality of both hardwar and software.