ARID - A model-based risk analysis approach

The first and maybe most important step in the development of complex safety-critical systems is the risk analysis. The ever increasing complexity today's systems require a stricter inter- pretation of risks. It is not sufficient to only focus on single service failures and assess their criticality. One has to be sure that every possible system risk, consisting of possibly more than one service failure, is acceptably safe. Standards such as the ISO 26262 show their awareness for those challenges, by stating that \multifunctional degradation" should be considered as well. This burdens the risk analy- sis process (in theory) with the challenge to consider not only the number of service failures, N_sf , but all possible combinations, resulting in an exponential amount of risk assessments 2_Nsf . In this paper we present how we can leverage system models together with failure propagation model information in order to structure and steer the risk assessment activities. The underlying formalization of ARID enables the handling of multifunctional degradation analysis.