An approach for the risk analysis of safety specifications

Experience in safety-critical systems has shown that faults introduced during requirements analysis can and do cause accidents. Within a methodology for the systematic production of requirements specifications for safety, based on a framework to structure the analysis and the application of formal techniques, we focus, in this paper on the risk analysis of the specifications. This has the aim to locate and remove faults during the requirements phase, rather than later in development or during the operational lifetime of the system. The applicability of the proposed approach is demonstrated by conducting the risk analysis of an example based on a train set crossing. The example illustrates how the approach to risk analysis supports verification within a formal model and how the validation of the formal model is performed