Research on methodology for safety generation and verification

Many safety-critical systems accidents can be due to the problems of requirements. Identifying and solving the problems in the requirements can reduce the cost and difficulties when the designs need change. Considering the requirements analysis methods, most are concerned only with the problem of components failures, which are hard to find out the hazards that can be led to by the dangerous interaction between different components. In this paper, a new method, analyzing the requirements by STPA (System-Theoretic Process Analysis) to generate the safety requirements and using the Stateflow toolbox to verify the requirements, is presented. Besides, this method is applied to analyze automatic train protection system. and the results show this method is valid for the generation and verification of safety requirements during the early phase of the system design.