Petri Net and Fault Tree analysis : combining two techniques for a software safety analysis on an embedded military application

Abstract

Software safety ensures that software programs, which control complex systems, perform within certain limits without resulting in an unacceptable risk of an accident occurring. Petri Nets are used to model concurrent computer systems by helping to understand complex interactions and paths of execution. Fault Tree analysis is used to determine safety requirements by detecting software logic errors. They also identify multiple failure sequences in a system that can lead to safety hazards. Petri Nets and Fault Tree analysis can be combined and used in conjunction with each other. They can take advantage of each others inherent strengths. This combined methodology can provide an efficient and effective safety analysis technique. This thesis surveys software safety research and focuses on Petri Nets and Fault Tree analysis. We discuss an extended example combining Petri Nets and Fault Tree analysis. The example is a real-time, military embedded software application. We then indicate directions for further research.