Generation of Safety Case Argument-Fragments from Safety Contracts

Composable safety certification envisions reuse of safety case argument-fragments together with safety-relevant components in order to reduce the cost and time needed to achieve certification. The argument-fragments could cover safety aspects relevant for different contexts in which the component can be used. Creating argument-fragments for the out-of-context components is time-consuming and currently no satisfying approach exists to facilitate their automatic generation. In this paper we propose an approach based on (semi-)automatic generation of argument-fragments from assumption/guarantee safety contracts. We use the contracts to capture the safety claims related to the component, including supporting evidence. We provide an overview of the argument-fragment architecture and rules for automatic generation, including their application in an illustrative example. The proposed approach enables safety engineers to focus on increasing the confidence in the knowledge about the system, rather than documenting a safety case.