Why Liveness for Timed Automata Is Hard, and What We Can Do About It

Herbreteau, Frédéric; Srivathsan, B.; Tran, Thanh-Tung; Walukiewicz, Igor

doi:10.1145/3372310

Cited by 10 publications

(22 citation statements)

References 19 publications

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“…Moreover, we show that such an approach can be used not only for Parametric Timed Automata but also for models featuring a progress measure which can be used to determine layers. Another nice feature is that the absence of cycles in the subsumed graph guarantees that no cycle exists in the PZG either, thus providing a quick answer when the formula holds, as exploited in [15].…”

Section: Resultsmentioning

confidence: 99%

“…In order to obtain a result as fast as possible, and with the largest parametric zone as possible, we run the blue search until the parametric zone changes (ll. [13][14][15]. The last state thus constructed is kept as Pending (l.14), i.e.…”

Section: Starting the Red Search Early: A Layered Ndfsmentioning

confidence: 99%

“…Due to the nature of the parametric zones we identified additional pruning opportunities. Another extension of NDFS with subsumption for TA was studied in [15]. Those authors proved that LTL model checking for TA is inherently harder than reachability checking for TA.…”

Section: Introductionmentioning

confidence: 99%

“…Cyan := Cyan \ {s} 14: procedure dfsRed (s)15:Red := Red ∪ {s} 16: for all t in NEXT-STATE(s) do 17:if t ∈ Cyan then report cycle18: …”

mentioning

confidence: 99%

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Layered and Collecting NDFS with Subsumption for Parametric Timed Automata

Nguyen¹,

Petrucci²,

Pol³

2018

2018 23rd International Conference on Engineering of Complex Computer Systems (ICECCS)

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This paper studies the analysis and parameter synthesis problems for Parametric Timed Automata (PTA) with properties in Linear-time Temporal Logic (LTL). It introduces a series of variations of Nested Depth-First Search (NDFS). We first study the LTL model checking problem for PTA. Based on a careful analysis of parametric zones, we introduce a new layered NDFS approach to LTL model checking. We integrate this with several techniques to prune the search space. In particular, we apply subsumption abstraction to PTA for the first time. We also propose heuristics on the search order to improve the performance. Next, we study parameter synthesis. To this end, this new layered approach and subsumption are added to a Collecting NDFS scheme. We implemented all algorithms in the IMITATOR tool and analyse their efficiency in a number of experiments.

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Section: Resultsmentioning

confidence: 99%

Section: Starting the Red Search Early: A Layered Ndfsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Cyan := Cyan \ {s} 14: procedure dfsRed (s)15:Red := Red ∪ {s} 16: for all t in NEXT-STATE(s) do 17:if t ∈ Cyan then report cycle18: …”

mentioning

confidence: 99%

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Layered and Collecting NDFS with Subsumption for Parametric Timed Automata

Nguyen¹,

Petrucci²,

Pol³

2018

2018 23rd International Conference on Engineering of Complex Computer Systems (ICECCS)

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“…Thus, the role of the controller is to choose transitions and delays. This problem has been studied numerously in the exact setting [13][14][15]17,19,27,28]. In the context of robustness, this strategy should be tolerant to small perturbations of the delays.…”

Section: Introductionmentioning

confidence: 99%

Robust Controller Synthesis in Timed Büchi Automata: A Symbolic Approach

Busatto-Gaston

Monmege

Reynier

et al. 2019

Computer Aided Verification

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We solve in a purely symbolic way the robust controller synthesis problem in timed automata with Büchi acceptance conditions. The goal of the controller is to play according to an accepting lasso of the automaton, while resisting to timing perturbations chosen by a competing environment. The problem was previously shown to be PSPACEcomplete using regions-based techniques, but we provide a first tool solving the problem using zones only, thus more resilient to state-space explosion problem. The key ingredient is the introduction of branching constraint graphs allowing to decide in polynomial time whether a given lasso is robust, and even compute the largest admissible perturbation if it is. We also make an original use of constraint graphs in this context in order to test the inclusion of timed reachability relations, crucial for the termination criterion of our algorithm. Our techniques are illustrated using a case study on the regulation of a train network. This work was funded by ANR project Ticktac (ANR-18-CE40-0015).

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Verified Certification of Reachability Checking for Timed Automata

Wimmer

Mutius

2020

Lecture Notes in Computer Science

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Prior research has shown how to construct a mechanically verified model checker for timed automata, a popular formalism for modeling real-time systems. In this paper, we shift the focus from verified model checking to certifying unreachability. This allows us to benefit from better approximation operations for symbolic states, and reduces execution time by exploring fewer states and by exploiting parallelism. Moreover, this gives us the ability to audit results of unverified model checkers that implement a range of further optimizations, including certificate compression. The resulting tool is evaluated on a set of standard benchmarks to demonstrate its practicality, using a new unverified model checker implementation in Standard ML to construct the certificates.

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Why Liveness for Timed Automata Is Hard, and What We Can Do About It

Cited by 10 publications

References 19 publications

Layered and Collecting NDFS with Subsumption for Parametric Timed Automata

Layered and Collecting NDFS with Subsumption for Parametric Timed Automata

Robust Controller Synthesis in Timed Büchi Automata: A Symbolic Approach

Verified Certification of Reachability Checking for Timed Automata

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