Probabilistic Failure Propagation and Transformation Analysis

A key concern in safety engineering is understanding the overall emergent failure behaviour of a system, i.e., behaviour exhibited by the system that is outside its specification of acceptable behaviour. A system can exhibit failure behaviour in many ways, including that from failures of individual or a small number of components. It is important for safety engineers to understand how system failure behaviour relates to failures exhibited by individual components. In this paper, we propose a safety analysis technique, failure propagation and transformation analysis (FPTA), which automatically and quantitatively analyses failures based on a model of failure logic. The technique integrates previous work on automated failure analysis with probabilistic model checking supported by the PRISM tool. We demonstrate the technique and tool on a small, yet realistic safety-related application.