Safety Analysis of Computer-Controlled Real-Time Systems with Message Loss Using Communicating DEVS Models

Abstract

The Communication DEVS formalism is an analysis means for discrete event systems modeled by DEVS formalism which has been widely used as a system theoretical specification. This paper proposes a new method for analyzing safety of real-time discrete event systems using communicating DEVS formalism. It is a part of efforts toward a unified method for modeling, simulation, and logical analysis based on the DEVS formalism and associate theory. For safety analysis of such real-time discrete event systems we first define communicating DEVS and then propose a timed reachability analysis algorithm for the models. The algorithm visits all possible timed states of the model, which is not always possible by using a simulation based state traversal. The proposed method can be well used especially for DEVS-specified systems to check various logical properties such safety, liveness and so on. A case study of a safety analysis for a rail road crossing system illustrates the usefulness of the proposed method.