On Reachability Analysis of Updatable Timed Automata with One Updatable Clock

As an extension of Timed Automata (TAs), Updatable Timed Automata (UTAs) proposed by Bouyer et al. have the ability to update clocks in a more elaborate way than simply reset them to zero. The reachability of general UTAs is undecidable, by regarding a pair of updatable clocks as counters updatable with incrementation and decrementation operations. This paper investigates the model of subclass of UTAs by restricting the number of updateable clocks. It is shown that the reachability of UTAs with one updatable clock (UTA1s) under diagonal-free constraints is decidable. The decidability is proved by treating a region of a UTA1 as an unbounded digiword, and encoding sets of digiwords that are accepted by a pushdown system where regions are generated on-the-fly on the stack.

[1]  Patricia Bouyer,et al.  Expressiveness of Updatable Timed Automata , 2000, MFCS.

[2]  Ashutosh Trivedi,et al.  Recursive Timed Automata , 2010, ATVA.

[3]  Patricia Bouyer,et al.  Are Timed Automata Updatable? , 2000, CAV.

[4]  Parosh Aziz Abdulla,et al.  Model checking of systems with many identical timed processes , 2003, Theor. Comput. Sci..

[5]  Stefan Schwoon,et al.  Model checking pushdown systems , 2002 .

[6]  Christian Choffrut,et al.  Timed Automata with Periodic Clock Constraints , 2000, J. Autom. Lang. Comb..

[7]  J. Ouaknine,et al.  On the language inclusion problem for timed automata: closing a decidability gap , 2004, LICS 2004.

[8]  Patricia Bouyer,et al.  Updatable timed automata , 2004, Theor. Comput. Sci..

[9]  Parosh Aziz Abdulla,et al.  Verifying Networks of Timed Processes (Extended Abstract) , 1998, TACAS.

[10]  Wieslaw Zielonka,et al.  Controlled Timed Automata , 1998, CONCUR.

[11]  Guoqiang Li,et al.  An Over-Approximation Forward Analysis for Nested Timed Automata , 2014, SOFL+MSVL.

[12]  Patricia Bouyer,et al.  Forward Analysis of Updatable Timed Automata , 2004, Formal Methods Syst. Des..

[13]  Rajeev Alur,et al.  A Theory of Timed Automata , 1994, Theor. Comput. Sci..

[14]  Guoqiang Li,et al.  A Refined Algorithm for Reachability Analysis of Updatable Timed Automata , 2015, 2015 IEEE International Conference on Software Quality, Reliability and Security - Companion.

[15]  Guoqiang Li,et al.  Nested Timed Automata with Frozen Clocks , 2015, FORMATS.

[16]  Guoqiang Li,et al.  Nested Timed Automata , 2013, FORMATS.