Verification of the Consistency of Time-Aware Cyber-Physical Processes

Abstract

Cyber-physical systems (CPS) represent an emerging type of distributed systems that integrate a multitude of physical elements and software applications into large networks of interconnected components. Ensuring that such systems meet their timing requirements is essential, especially with time-sensitive applications. To deal with this, suitable ways to specify and verify distributed CPS applications including their timing requirements are needed. Current CPS modeling solutions specify CPS as inter-organizational processes using existing process modeling languages. However, the existing process modeling languages mostly focus on web-based workflow and are not directly compatible with CPS. Modeling processes in CPS requires the consideration of cyber elements, physical elements, and their non-functional properties such as time-related and physical properties. Given an inter-organizational CPS processes model with considering structural and non-functional properties, implicit conflicts may arise. To deal with this issue, we propose an approach for modeling and verifying inter-organizational cyber-physical processes associated with temporal properties. To do that, we provide an extended version of BPMN that supports CPS concepts and properties. Then, we define a set of transformation rules to automatically transform the inter-organizational processes model into a constraint satisfaction model. Thereafter, we analyze the generated model to check its consistency.