An extended systematic literature review on provision of evidence for safety certification (original) (raw)

2014, Information and Software Technology

Software Certification: Is There a Case against Safety Cases?

Safety cases have become popular, even mandated, in a number of jurisdictions that develop products that have to be safe. Prior to their use in software certification, safety cases were already in use in domains like aviation, military applications, and the nuclear industry. Argument based methodologies/approaches have recently become the cornerstone for structuring justification and evidence to support safety claims. We believe that the safety case methodology is useful for the software certification domain, but needs to be tailored, more clearly defined, and more appropriately structured in analogy with regulatory regimes in classical engineering disciplines. This paper presents a number of reasons as to why current approaches to safety cases do not satisfy essential attributes for an effective software certification process and proposes improvements based on lessons learned from other engineering disciplines. In particular, the safety case approach lacks the highly prescriptive and domain specific nature that can be seen in other engineering specialities, in terms of engineering and analysis methods to be applied in generating the relevant evidence. Safety case approaches and corresponding methods should aim to achieve the levels of precision and effectiveness of engineering methods underpinning regulatory regimes in other engineering disciplines.

Towards Rigorous Construction of Safety Cases

Nowadays, certification of safety-critical software systems requires submission of safety assurance documents, often in the form of safety cases. A safety case is a justification argument used to show that a system is safe for a particular application in a particular environment. Different argumentation strategies are applied to derive the evidence for a safety case. They allow us to support a safety case with such evidence as results of hazard analysis, testing, simulation, etc. On the other hand, application of formal methods for development and verification of critical software systems is mandatory for their certification. In this paper, we propose a methodology that combines these two activities. Firstly, it allows us to map the given safety requirements into elements of the formal model to be constructed, which is then used for verification of these requirements. Secondly, it guides the construction of a safety case demonstrating that the safety requirements are indeed met. Con...

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