Providing tool support for specifying safety-critical systems by enforcing syntactic contract conditions

Functional safety standards such as IEC 61508 and ISO 26262 advocate a particularly stringent requirements engineering where safety requirements must be structured in a hierarchical manner and specified in accordance with the system architecture. In contrast to the stringent requirements engineering in functional safety standards, according to previous studies, requirements engineering in industry is in general of poor quality. Contracts theory has been previously shown to be suitable for supporting such a stringent requirements engineering effort; this support has also been implemented in tools. However, to use these contract-based tools, requirements must be formalized, which is a major challenge in industry. Therefore, to support current industrial requirements engineering practice and the stringent requirements engineering in functional safety standards, it is shown how tool support can be provided even when requirements, and also architectures, are not formalized. This is achieved by enforcing syntactic, yet formal, conditions in contracts theory. Despite the need for further validation, initial findings in an industrial case study indicate high potential in realizing the proposed support in an industrial setting.