Integrating Safety Analysis With Functional Modeling

Functional modeling and safety analysis are two important aspects of safety-critical embedded systems. However, they are often conducted separately. In this paper, we present an approach for integrating fault-tree-based safety analysis into statechart-based functional modeling. The proposed approach uses systematic transformation steps that maintain the semantics of both the fault tree and the statechart. It also provides a set of conversion rules that transform the gates of fault trees into statechart notations. The resultant model shows how the system behaves when a failure condition occurs and acts as a basis model that ensures safety through requirement validation. Using the gas burner case study, we demonstrate the advantages of the integrated model over the use of separate models, such as the lack of ambiguities, separation of concerns, and taking the order of the occurrence of faults into consideration.