Checking Timed Bisimilarity with Virtual Clocks

Fuente: arXiv
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Main Authors: Lieb, Alexander, Göttmann, Hendrik, Luthmann, Lars, Lochau, Malte, Schürr, Andy
Format: Preprint
Published: 2024
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_version_ 1866917370478460928
author Lieb, Alexander
Göttmann, Hendrik
Luthmann, Lars
Lochau, Malte
Schürr, Andy
author_facet Lieb, Alexander
Göttmann, Hendrik
Luthmann, Lars
Lochau, Malte
Schürr, Andy
contents Timed automata are a widely used formalism for specifying the discrete-state/continuous-time behavior of time-critical reactive systems. For the fundamental verification problem of comparing two timed automata, it has been shown that timed trace equivalence is undecidable, while timed bisimulation is decidable. The corresponding decidability proof uses region graphs, a finite but space-consuming characterization of timed automata semantics. Most verification tools use zone graphs instead, a symbolic and, on average, more space-efficient representation of timed automata semantics. However, zone graphs provide correct results only for those verification tasks that are reducible to reachability problems, and are too imprecise for timed bisimilarity checking. To the best of our knowledge, there is currently no practical tool for automated timed bisimilarity checking. In this paper, we propose a new representation of timed automata semantics that extends zone graphs by so-called virtual clocks. Our zone-based construction is, on average, significantly smaller than the corresponding region graph representation. We also present experimental results obtained by applying our tool implementation to timed automata models, which are often used to evaluate timed automata analysis techniques.
format Preprint
id arxiv_https___arxiv_org_abs_2412_15799
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Checking Timed Bisimilarity with Virtual Clocks
Lieb, Alexander
Göttmann, Hendrik
Luthmann, Lars
Lochau, Malte
Schürr, Andy
Formal Languages and Automata Theory
F.1.1
Timed automata are a widely used formalism for specifying the discrete-state/continuous-time behavior of time-critical reactive systems. For the fundamental verification problem of comparing two timed automata, it has been shown that timed trace equivalence is undecidable, while timed bisimulation is decidable. The corresponding decidability proof uses region graphs, a finite but space-consuming characterization of timed automata semantics. Most verification tools use zone graphs instead, a symbolic and, on average, more space-efficient representation of timed automata semantics. However, zone graphs provide correct results only for those verification tasks that are reducible to reachability problems, and are too imprecise for timed bisimilarity checking. To the best of our knowledge, there is currently no practical tool for automated timed bisimilarity checking. In this paper, we propose a new representation of timed automata semantics that extends zone graphs by so-called virtual clocks. Our zone-based construction is, on average, significantly smaller than the corresponding region graph representation. We also present experimental results obtained by applying our tool implementation to timed automata models, which are often used to evaluate timed automata analysis techniques.
title Checking Timed Bisimilarity with Virtual Clocks
topic Formal Languages and Automata Theory
F.1.1
url https://arxiv.org/abs/2412.15799