Investigating Process Algebra Models to Represent Structured Requirements for Time-sensitive CPS

Abstract

Cyber-Physical Systems (CPS) contain complex computational components that control physical entities. The design of these components must take into account the realtime and concurrent nature of these systems. Formulating requirements that describe CPS behaviors precisely, ruling out misunderstandings, is a crucial yet difficult endeavor. To increase trust in the requirements, formal methods can be used to check relevant properties of the requirements. We investigate a process algebra to capture real-time behaviors and concurrency in CPS requirements in order to automate their analysis. We use a structured natural language to first express CPS requirements: this takes into account current practice, indeed requirements should be easily writable as well as graspable by stakeholders with various points of view and ease communication among them. At the same time, requirements analysis using simulation or formal validation is possible by taking advantage of the requirements structure. We discuss translation from the structured requirements into the process algebra to automate the overall process. Our approach is implemented and is illustrated by an example issued from CPS4EU project 1 .