The Use of Controlled Vocabularies and Structured Expressions in the Assurance of CPS

To date, work on the development of assurance cases has largely been concerned with the broad structure and content of arguments to contextualise the data. However, at a more detailed level, use of natural language in an argument can lead to conflicting terminology, to difficulties in understanding the nature of the claims being made or to logical inferences which are obscure to the readers of the argument. This problem has become increasingly complex as more and more suppliers are involved in the development chain, making it more difficult to evaluate the strengths and weaknesses of assurance data or to re-use it. This paper explores the development of controlled vocabulary and structured expressions for CPS in the automotive domain, using the Semantics of Business Vocabulary and Business Rules (SBVR) to improve communication and to provide presents some formal consistency checking of content. We highlight the challenges this work has exposed. Keywords: safety, assurance, controlled language, SBVR, automotive.