Using partial orders for the efficient verification of deadlock freedom and safety properties
Formal Methods in System Design - Special issue on computer-aided verification: special methods II
Theoretical Computer Science
Model checking of systems with many identical timed processes
Theoretical Computer Science
ICALP '92 Proceedings of the 19th International Colloquium on Automata, Languages and Programming
Dynamical Properties of Timed Automata
FTRTFT '98 Proceedings of the 5th International Symposium on Formal Techniques in Real-Time and Fault-Tolerant Systems
HART '97 Proceedings of the International Workshop on Hybrid and Real-Time Systems
Revisiting Digitization, Robustness, and Decidability for Timed Automata
LICS '03 Proceedings of the 18th Annual IEEE Symposium on Logic in Computer Science
LICS '04 Proceedings of the 19th Annual IEEE Symposium on Logic in Computer Science
Universality and language inclusion for open and closed timed automata
HSCC'03 Proceedings of the 6th international conference on Hybrid systems: computation and control
On the verification of timed ad hoc networks
FORMATS'11 Proceedings of the 9th international conference on Formal modeling and analysis of timed systems
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We consider verification of safety properties for parameterized systems of timed processes, so called timed networks. A timed network consists of a finite state process, called a controller, and an arbitrary set of identical timed processes. In [Parosh Aziz Abdulla and Bengt Jonsson. Model checking of systems with many identical timed processes. Theoretical Computer Science, 290(1):241-264, 2003] it was shown that checking safety properties is decidable in the case where each timed process is equipped with a single real-valued clock. In [P. Abdulla, J. Deneux, and P. Mahata. Multi-clock timed networks. In Proc. LICS' 04, pages 345-354. IEEE Computer Society Press, 2004], we showed that this is no longer possible if each timed process is equipped with at least two real-valued clocks. In this paper, we study two subclasses of timed networks: closed and open timed networks. In closed timed networks, all clock constraints are non-strict, while in open timed networks, all clock constraints are strict (thus corresponds to syntactic removal of equality testing). We show that the problem becomes decidable for closed timed network, while it remains undecidable for open timed networks. We also consider robust semantics of timed networks by introducing timing fuzziness through semantic removal of equality testing. We show that the problem is undecidable both for closed and open timed networks under the robust semantics.