Software Reliability Assessment for Branching Structures: A Hierarchical Approach

An increased use of software systems in safety–critical applications has made the estimation of the software probability of failure on demand (pfd) an issue of great importance. In this paper, estimation of the system pfd is based on the decomposition of the system into a set of sub–systems with independent failure behaviour. Structures which fork and then join again can pose a problem when it comes to defining independently failing sub-systems. A Bayesian approach performed on two levels of granularity is suggested to perform system pfd estimation on such structures.