Composing real-time concurrent objects: refinement, compatibility and schedulability

TL;DR: This paper defines refinement of timed automata with inputs and outputs from a new perspective and takes account of deadlines in the refinement theory of real-time concurrent objects, and applies it in the context of compositional schedulability analysis of multiple-processor systems.

Abstract: Concurrent objects encapsulate a processor each and communicate by asynchronous message passing; therefore, they can be composed to naturally model distributed and embedded systems. We model real-time concurrent objects using timed automata and provide each object with a context-specific scheduling policy. The envisioned usage and guaranteed deadlines of each object is specified in its behavioral interface, given also in timed automata. Furthermore, multiple objects can be composed only if they are compatible, i.e., if they respect the expected use patterns given in the behavioral interfaces of each other. In this paper, we define refinement of timed automata with inputs and outputs from a new perspective and we take account of deadlines in the refinement theory. Within this framework, we study composition and compatibility of real-time concurrent objects, and apply it in the context of compositional schedulability analysis of multiple-processor systems.