On Implementing Real-time Specification Patterns Using Observers
This work addresses the problem of transforming English language requirements with real-time constraints into formal specifications for cyber-physical systems, but it is incremental as it builds on existing specification patterns and observer methods.
The paper tackled the challenge of accurately expressing real-time specification patterns in formal languages like AGREE using observers, revealing subtle issues not previously documented, and demonstrated their sufficiency for modeling real-time requirements in a real-world avionics system.
English language requirements are often used to specify the behavior of complex cyber-physical systems. The process of transforming these requirements to a formal specification language is often challenging, especially if the specification language does not contain constructs analogous to those used in the original requirements. For example, requirements often contain real-time constraints, but many specification languages for model checkers have discrete time semantics. Work in specification patterns helps to bridge these gaps, allowing straightforward expression of common requirements patterns in formal languages. In this work we demonstrate how we support real-time specification patterns in the Assume Guarantee Reasoning Environment (AGREE) using observers. We demonstrate that there are subtle challenges, not mentioned in previous literature, to express real-time patterns accurately using observers. We then demonstrate that these patterns are sufficient to model real-time requirements for a real-world avionics system.