Propagation, Transformation and Refinement of Safety Requirements

Safety requirements are an important artifact in the development of safety critical systems. They are used by experts as a basis for appropriate selection and implementation of fault detection mechanisms. Various research groups have worked on their formal modeling with the goal of determining if a system can meet these requirements. In this paper, we propose the application of formal models of safety requirements throughout all constructive development phases of a modeldriven development process to automatically generate appropriate fault detection mechanisms. The main contribution of this paper is a rigorous formal specification of safety requirements that allows the automatic propagation, transformation and refinement of safety requirements and the derivation of appropriate fault detection mechanisms. This is an important step to guarantee consistency and completeness in the critical transition from requirements engineering to software design, where a lot of errors can be introduced into a system by using conventional, nonformal techniques.