Timed-rebeca schedulability and deadlock-freedom analysis using floating-time transition system

Abstract

"Timed-Rebeca" is an actor-based modeling language for modeling real-time reactive systems. Its high-level constructs make it more suitable for using it by software practitioners compared to timed-automata based alternatives. Currently, the verification of Timed-Rebeca models is done by converting into timed-automata and using UPPAAL toolset to analyze the model. However, state space explosion and time consumption are the major limitations of using the back-end timed automata model for verification. In this paper, we propose a new approach for direct schedulability checking and deadlock freedom verification of Timed-Rebeca models. The new approach exploits the key feature of Timed-Rebeca, which is encapsulation of concurrent elements. In the proposed method, each state stores the local time of each actor separately, avoiding the need for a global time in the state. This significantly decreases the size of the state space. We prove the bisimilarity of the generated transition system (called floating-time transition system) and the state space generated based on Timed-Rebeca semantics. Also, we provide experimental results showing that the new approach mitigates the state space explosion problem of the former method and allows model-checking of larger problems.