Safety analysis for safety-critical system based on boilerplate and Alloy

Abstract

As the complexity of the safety-critical system grows, the difficulty for safety engineers to validate and ensure system safety increases too. Formal languages have been introduced as an alternative to natural language (NL) requirement descriptions. Sometimes, the safety requirements are put forward in natural language such as requirements from stakeholders and nonexperts. The transformation and verification work of the requirements are completed manually. A tool called DODT can semi-automatically transforms NL requirements into semi-formal boilerplate requirements which reduce the manual work of transformation largely. Alloy is a formal modeling language which is amenable to automatic analyses. We use it as a tool to make safety analysis taking benefit from the model-based aspect of Alloy and its expressiveness for the specification of the properties to check. In this paper, we combine DDOT with Alloy. The attributes we use in boilerplates can be transformed into Alloy sentences easily. Hence, the formal requirements can be expressed in Alloy easily and checked by Alloy Analyzer, reducing manual work largely. Last, we illustrate our method with a fire detection system.