Avoiding Shared Clocks in Networks of Timed Automata

Abstract

AbstractNetworks of timed automata (NTA) are widely used to model distributed real-time systems. Quite often in the literature, the automata are allowed to share clocks. This is a problem when one considers implementing such model in a distributed architecture, since reading clocks a priori requires communications which are not explicitly described in the model. We focus on the following question: given a NTA A 1 ∥ A 2 where A 2 reads some clocks reset by A 1, does there exist a NTA A′1 ∥ A′2 without shared clocks with the same behavior as the initial NTA? For this, we allow the automata to exchange information during synchronizations only. We discuss a formalization of the problem and give a criterion using the notion of contextual timed transition system, which represents the behavior of A 2 when in parallel with A 1. Finally, we effectively build A′1 ∥ A′2 when it exists.Keywordsnetworks of timed automatashared clocksimplementation on distributed architecturecontextual timed transition systembehavioral equivalence for distributed systems