The application of Bayesian Belief Networks to assurance case preparation

Abstract

Designers of dependable systems need to present assurance cases that support the claims made about the system's dependability. Building this assurance case, incorporating different types of evidence and reasoning, can be daunting. In this paper we argue that, thanks to their flexibility and expressive capabilities, Bayesian Belief Networks are particularly suitable for building such assurance cases. Drawing on our experience preparing and presenting an assurance case to certify a software product to IEC 61508 Safety Integrity Level 3, we describe how Bayesian Belief Networks can be used to simplify both the engineer's work in preparing the case, and the auditor's or customer's work in checking this case for coherence and completeness. © Springer-Verlag London Limited 2012.