Formal fault tree construction and system safety analysis

Fault Tree Analysis is a traditional deductive safety analysis technique that is applied during the system design stage. However, traditional fault trees often suffer from a lack of formal semantics to check the correctness or consistency of the descriptions. This is especially a problem in safety-critical system analysis. To overcome this limitation, we propose a novel formal fault tree construction method, which is different from traditional methods that focus on providing the formal semantics for the fault tree constructs after the informal fault tree has been built. In our method, the correctness of the fault tree is proved by the construction process itself, and the time relationships among different events are guaranteed by introducing temporal logic notations. Furthermore, by the stepwise deduction process, the hidden domain rules and inattentive design deficiencies can be discovered at an earlier stage, which helps the designers and domain experts effectively check and revise their system design in a timelier manner.