Parameterized Verification of Disjunctive Timed Networks

TL;DR

This paper presents new techniques for parameterized verification of disjunctive timed networks, enabling efficient analysis of complex timed automata systems with location guards and clock invariants.

Contribution

Introduces a novel zone graph algorithm for Minreach, constructs summary automata, and extends verification methods to cases with location invariants.

Findings

Efficient solution for Minreach in DTNs.

Construction of summary automata for arbitrary-sized networks.

Practical implementation with positive experimental results.

Abstract

We introduce new techniques for the parameterized verification of disjunctive timed networks (DTNs), i.e., networks of timed automata (TAs) that communicate via location guards that enable a transition only if there is another process in a given location. This computational model has been considered in the literature before, example applications are gossiping clock synchronization protocols or planning problems. We address the minimum-time reachability problem (Minreach) in DTNs, and show how to efficiently solve it based on a novel zone graph algorithm. We further show that solving Minreach allows us to construct a summary TA capturing exactly the possible behaviors of a single TA within a DTN of arbitrary size. The combination of these two results enables the parameterized verification of DTNs, while avoiding the construction of an exponential-size cutoff system required by existing results. Additionally, we develop sufficient conditions for solving Minreach and parameterized verification problems even in certain cases where locations that appear in location guards can have clock invariants, a case that has usually been excluded in the literature. Our techniques are also implemented, and experiments show their practicality.