Formal Requirements in an Informal World

With today’s increasing complexity of systems andrequirements there is a need for formal analysis of requirements.Although there exist several formal requirements description lan-guages and corresponding analysis tools that target an industrialaudience, there is a large gap between the form of requirementsand the training in formal methods available in industry today,and the form of requirements and the knowledge that is necessaryto successfully operate the analysis tools. We propose a process to bridge the gap between customerrequirements and formal analysis. The process is designed tosupport in-house formalisation and analysis as well as formalisa-tion and analysis as a service provided by a third party. The basicideas are that we obtain dependability and comprehensibility byassuming a senior formal requirements engineer who preparesthe requirements and later interprets the analysis results intandem with the client. We obtain scalability as most of theformalisation and analysis is supposed to be conducted by juniorformal requirements engineers. In this paper, we define and analyse the process and report onexperience from different instantiations, where the process waswell received by customers.