15 Search Results for "Krishna, S."

Document
DOI: 10.4230/LIPIcs.FSTTCS.2021.33
Resilience of Timed Systems

Authors: S. Akshay, Blaise Genest, Loïc Hélouët, S. Krishna, and Sparsa Roychowdhury

Published in: LIPIcs, Volume 213, 41st IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2021)

Abstract
This paper addresses reliability of timed systems in the setting of resilience, that considers the behaviors of a system when unspecified timing errors such as missed deadlines occur. Given a fault model that allows transitions to fire later than allowed by their guard, a system is universally resilient (or self-resilient) if after a fault, it always returns to a timed behavior of the non-faulty system. It is existentially resilient if after a fault, there exists a way to return to a timed behavior of the non-faulty system, that is, if there exists a controller which can guide the system back to a normal behavior. We show that universal resilience of timed automata is undecidable, while existential resilience is decidable, in EXPSPACE. To obtain better complexity bounds and decidability of universal resilience, we consider untimed resilience, as well as subclasses of timed automata.
Cite as

S. Akshay, Blaise Genest, Loïc Hélouët, S. Krishna, and Sparsa Roychowdhury. Resilience of Timed Systems. In 41st IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 213, pp. 33:1-33:22, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2021)

Copy BibTex To Clipboard

@InProceedings{akshay_et_al:LIPIcs.FSTTCS.2021.33,
  author =	{Akshay, S. and Genest, Blaise and H\'{e}lou\"{e}t, Lo\"{i}c and Krishna, S. and Roychowdhury, Sparsa},
  title =	{{Resilience of Timed Systems}},
  booktitle =	{41st IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2021)},
  pages =	{33:1--33:22},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-215-0},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{213},
  editor =	{Boja\'{n}czyk, Miko{\l}aj and Chekuri, Chandra},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSTTCS.2021.33},
  URN =		{urn:nbn:de:0030-drops-155442},
  doi =		{10.4230/LIPIcs.FSTTCS.2021.33},
  annote =	{Keywords: Timed automata, Fault tolerance, Integer-resets, Resilience}
}
Document
DOI: 10.4230/LIPIcs.TIME.2021.17
1½-Player Stochastic StopWatch Games

Authors: Sparsa Roychowdhury

Published in: LIPIcs, Volume 206, 28th International Symposium on Temporal Representation and Reasoning (TIME 2021)

Abstract
Stochastic timed games (STGs), introduced by Bouyer and Forejt, generalize continuous-time Markov chains and timed automata. Depending on the number of players - 2, 1, or 0 - subclasses of stochastic timed games are classified as 2½-player, 1½-player, and ½-player games where the ½ symbolizes the presence of the stochastic player. The qualitative and quantitative reachability problem for STGs was studied in [Patricia Bouyer and Vojtech Forejt, 2009] and [S. Akshay et al., 2016]. In this paper, we introduce stochastic stopwatch games (SSG), an extension of (STG) from clocks to stopwatches. We focus on 1½-player SSGs and prove that with two variables which can be either a clock or a stopwatch, qualitative reachability is decidable, whereas, if we increase the number of variables to three, with at least one stopwatch, the problem becomes undecidable.
Cite as

Sparsa Roychowdhury. 1½-Player Stochastic StopWatch Games. In 28th International Symposium on Temporal Representation and Reasoning (TIME 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 206, pp. 17:1-17:18, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2021)

Copy BibTex To Clipboard

@InProceedings{roychowdhury:LIPIcs.TIME.2021.17,
  author =	{Roychowdhury, Sparsa},
  title =	{{1½-Player Stochastic StopWatch Games}},
  booktitle =	{28th International Symposium on Temporal Representation and Reasoning (TIME 2021)},
  pages =	{17:1--17:18},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-206-8},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{206},
  editor =	{Combi, Carlo and Eder, Johann and Reynolds, Mark},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.TIME.2021.17},
  URN =		{urn:nbn:de:0030-drops-147934},
  doi =		{10.4230/LIPIcs.TIME.2021.17},
  annote =	{Keywords: Timed Automata, Stopwatches, Stochastic Timed Games}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2021.29
Scope-Bounded Reachability in Valence Systems

Authors: Aneesh K. Shetty, S. Krishna, and Georg Zetzsche

Published in: LIPIcs, Volume 203, 32nd International Conference on Concurrency Theory (CONCUR 2021)

Abstract
Multi-pushdown systems are a standard model for concurrent recursive programs, but they have an undecidable reachability problem. Therefore, there have been several proposals to underapproximate their sets of runs so that reachability in this underapproximation becomes decidable. One such underapproximation that covers a relatively high portion of runs is scope boundedness. In such a run, after each push to stack i, the corresponding pop operation must come within a bounded number of visits to stack i. In this work, we generalize this approach to a large class of infinite-state systems. For this, we consider the model of valence systems, which consist of a finite-state control and an infinite-state storage mechanism that is specified by a finite undirected graph. This framework captures pushdowns, vector addition systems, integer vector addition systems, and combinations thereof. For this framework, we propose a notion of scope boundedness that coincides with the classical notion when the storage mechanism happens to be a multi-pushdown. We show that with this notion, reachability can be decided in PSPACE for every storage mechanism in the framework. Moreover, we describe the full complexity landscape of this problem across all storage mechanisms, both in the case of (i) the scope bound being given as input and (ii) for fixed scope bounds. Finally, we provide an almost complete description of the complexity landscape if even a description of the storage mechanism is part of the input.
Cite as

Aneesh K. Shetty, S. Krishna, and Georg Zetzsche. Scope-Bounded Reachability in Valence Systems. In 32nd International Conference on Concurrency Theory (CONCUR 2021). Leibniz International Proceedings in Informatics (LIPIcs), Volume 203, pp. 29:1-29:19, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2021)

Copy BibTex To Clipboard

@InProceedings{shetty_et_al:LIPIcs.CONCUR.2021.29,
  author =	{Shetty, Aneesh K. and Krishna, S. and Zetzsche, Georg},
  title =	{{Scope-Bounded Reachability in Valence Systems}},
  booktitle =	{32nd International Conference on Concurrency Theory (CONCUR 2021)},
  pages =	{29:1--29:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-203-7},
  ISSN =	{1868-8969},
  year =	{2021},
  volume =	{203},
  editor =	{Haddad, Serge and Varacca, Daniele},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2021.29},
  URN =		{urn:nbn:de:0030-drops-144069},
  doi =		{10.4230/LIPIcs.CONCUR.2021.29},
  annote =	{Keywords: multi-pushdown systems, underapproximations, valence systems, reachability}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2020.16
On the Separability Problem of String Constraints

Authors: Parosh Aziz Abdulla, Mohamed Faouzi Atig, Vrunda Dave, and Shankara Narayanan Krishna

Published in: LIPIcs, Volume 171, 31st International Conference on Concurrency Theory (CONCUR 2020)

Abstract
We address the separability problem for straight-line string constraints. The separability problem for languages of a class C by a class S asks: given two languages A and B in C, does there exist a language I in S separating A and B (i.e., I is a superset of A and disjoint from B)? The separability of string constraints is the same as the fundamental problem of interpolation for string constraints. We first show that regular separability of straight line string constraints is undecidable. Our second result is the decidability of the separability problem for straight-line string constraints by piece-wise testable languages, though the precise complexity is open. In our third result, we consider the positive fragment of piece-wise testable languages as a separator, and obtain an ExpSpace algorithm for the separability of a useful class of straight-line string constraints, and a Pspace-hardness result.
Cite as

Parosh Aziz Abdulla, Mohamed Faouzi Atig, Vrunda Dave, and Shankara Narayanan Krishna. On the Separability Problem of String Constraints. In 31st International Conference on Concurrency Theory (CONCUR 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 171, pp. 16:1-16:19, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)

Copy BibTex To Clipboard

@InProceedings{abdulla_et_al:LIPIcs.CONCUR.2020.16,
  author =	{Abdulla, Parosh Aziz and Atig, Mohamed Faouzi and Dave, Vrunda and Krishna, Shankara Narayanan},
  title =	{{On the Separability Problem of String Constraints}},
  booktitle =	{31st International Conference on Concurrency Theory (CONCUR 2020)},
  pages =	{16:1--16:19},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-160-3},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{171},
  editor =	{Konnov, Igor and Kov\'{a}cs, Laura},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2020.16},
  URN =		{urn:nbn:de:0030-drops-128286},
  doi =		{10.4230/LIPIcs.CONCUR.2020.16},
  annote =	{Keywords: string constraints, separability, interpolants}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2020.42
Determinisability of One-Clock Timed Automata

Authors: Lorenzo Clemente, Sławomir Lasota, and Radosław Piórkowski

Published in: LIPIcs, Volume 171, 31st International Conference on Concurrency Theory (CONCUR 2020)

Abstract
The deterministic membership problem for timed automata asks whether the timed language recognised by a nondeterministic timed automaton can be recognised by a deterministic timed automaton. We show that the problem is decidable when the input automaton is a one-clock nondeterministic timed automaton without epsilon transitions and the number of clocks of the deterministic timed automaton is fixed. We show that the problem in all the other cases is undecidable, i.e., when either 1) the input nondeterministic timed automaton has two clocks or more, or 2) it uses epsilon transitions, or 3) the number of clocks of the output deterministic automaton is not fixed.
Cite as

Lorenzo Clemente, Sławomir Lasota, and Radosław Piórkowski. Determinisability of One-Clock Timed Automata. In 31st International Conference on Concurrency Theory (CONCUR 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 171, pp. 42:1-42:17, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)

Copy BibTex To Clipboard

@InProceedings{clemente_et_al:LIPIcs.CONCUR.2020.42,
  author =	{Clemente, Lorenzo and Lasota, S{\l}awomir and Pi\'{o}rkowski, Rados{\l}aw},
  title =	{{Determinisability of One-Clock Timed Automata}},
  booktitle =	{31st International Conference on Concurrency Theory (CONCUR 2020)},
  pages =	{42:1--42:17},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-160-3},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{171},
  editor =	{Konnov, Igor and Kov\'{a}cs, Laura},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2020.42},
  URN =		{urn:nbn:de:0030-drops-128542},
  doi =		{10.4230/LIPIcs.CONCUR.2020.42},
  annote =	{Keywords: Timed automata, determinisation, deterministic membership problem}
}
Document
Track B: Automata, Logic, Semantics, and Theory of Programming
DOI: 10.4230/LIPIcs.ICALP.2020.121
Timed Games and Deterministic Separability

Authors: Lorenzo Clemente, Sławomir Lasota, and Radosław Piórkowski

Published in: LIPIcs, Volume 168, 47th International Colloquium on Automata, Languages, and Programming (ICALP 2020)

Abstract
We study a generalisation of Büchi-Landweber games to the timed setting. The winning condition is specified by a non-deterministic timed automaton with epsilon transitions and only Player I can elapse time. We show that for fixed number of clocks and maximal numerical constant available to Player II, it is decidable whether she has a winning timed controller using these resources. More interestingly, we also show that the problem remains decidable even when the maximal numerical constant is not specified in advance, which is an important technical novelty not present in previous literature on timed games. We complement these two decidability result by showing undecidability when the number of clocks available to Player II is not fixed. As an application of timed games, and our main motivation to study them, we show that they can be used to solve the deterministic separability problem for nondeterministic timed automata with epsilon transitions. This is a novel decision problem about timed automata which has not been studied before. We show that separability is decidable when the number of clocks of the separating automaton is fixed and the maximal constant is not. The problem whether separability is decidable without bounding the number of clocks of the separator remains an interesting open problem.
Cite as

Lorenzo Clemente, Sławomir Lasota, and Radosław Piórkowski. Timed Games and Deterministic Separability. In 47th International Colloquium on Automata, Languages, and Programming (ICALP 2020). Leibniz International Proceedings in Informatics (LIPIcs), Volume 168, pp. 121:1-121:16, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2020)

Copy BibTex To Clipboard

@InProceedings{clemente_et_al:LIPIcs.ICALP.2020.121,
  author =	{Clemente, Lorenzo and Lasota, S{\l}awomir and Pi\'{o}rkowski, Rados{\l}aw},
  title =	{{Timed Games and Deterministic Separability}},
  booktitle =	{47th International Colloquium on Automata, Languages, and Programming (ICALP 2020)},
  pages =	{121:1--121:16},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-138-2},
  ISSN =	{1868-8969},
  year =	{2020},
  volume =	{168},
  editor =	{Czumaj, Artur and Dawar, Anuj and Merelli, Emanuela},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICALP.2020.121},
  URN =		{urn:nbn:de:0030-drops-125282},
  doi =		{10.4230/LIPIcs.ICALP.2020.121},
  annote =	{Keywords: Timed automata, separability problems, timed games}
}
Document
DOI: 10.4230/LITES-v004-i002-a003
Per Processor Spin-Based Protocols for Multiprocessor Real-Time Systems

Authors: Sara Afshar, Moris Behnam, Reinder J. Bril, and Thomas Nolte

Published in: LITES, Volume 4, Issue 2 (2017). Leibniz Transactions on Embedded Systems, Volume 4, Issue 2

Abstract
This paper investigates preemptive spin-based global resource sharing protocols for resource-constrained real-time embedded multi-core systems based on partitioned fixed-priority preemptive scheduling. We present preemptive spin-based protocols that feature (i) an increased schedulability ratio of task sets and reduced response jitter of tasks compared to the classical non-preemptive spin-based protocol, (ii) similar memory requirements for the administration of waiting tasks as for the non-preemptive protocol whilst only causing (iii) a minimal increase of the minimal number of required stacks per core from one to at most two, and (iv) strong progress guarantees to tasks. We complement these protocols with a unified worst-case response time analysis that specializes to the classical analysis for the non-preemptive protocol. The paper includes a comparative evaluation of the preemptive protocols and the non-preemptive protocol based on synthetic data.
Cite as

Sara Afshar, Moris Behnam, Reinder J. Bril, and Thomas Nolte. Per Processor Spin-Based Protocols for Multiprocessor Real-Time Systems. In LITES, Volume 4, Issue 2 (2017). Leibniz Transactions on Embedded Systems, Volume 4, Issue 2, pp. 03:1-03:30, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2018)

Copy BibTex To Clipboard

@Article{afshar_et_al:LITES-v004-i002-a003,
  author =	{Afshar, Sara and Behnam, Moris and Bril, Reinder J. and Nolte, Thomas},
  title =	{{Per Processor Spin-Based Protocols for Multiprocessor Real-Time Systems}},
  booktitle =	{LITES, Volume 4, Issue 2 (2017)},
  pages =	{03:1--03:30},
  journal =	{Leibniz Transactions on Embedded Systems},
  ISSN =	{2199-2002},
  year =	{2018},
  volume =	{4},
  number =	{2},
  editor =	{Afshar, Sara and Behnam, Moris and Bril, Reinder J. and Nolte, Thomas},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LITES-v004-i002-a003},
  doi =		{10.4230/LITES-v004-i002-a003},
  annote =	{Keywords: Resource sharing, Real-time systems, Multiprocessors, Spin-locks}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2017.39
Towards an Efficient Tree Automata Based Technique for Timed Systems

Authors: S. Akshay, Paul Gastin, Shankara Narayanan Krishna, and Ilias Sarkar

Published in: LIPIcs, Volume 85, 28th International Conference on Concurrency Theory (CONCUR 2017)

Abstract
The focus of this paper is the analysis of real-time systems with recursion, through the development of good theoretical techniques which are implementable. Time is modeled using clock variables, and recursion using stacks. Our technique consists of modeling the behaviours of the timed system as graphs, and interpreting these graphs on tree terms by showing a bound on their tree-width. We then build a tree automaton that accepts exactly those tree terms that describe realizable runs of the timed system. The emptiness of the timed system thus boils down to emptiness of a finite tree automaton that accepts these tree terms. This approach helps us in obtaining an optimal complexity, not just in theory (as done in earlier work e.g.[concur16]), but also in going towards an efficient implementation of our technique. To do this, we make several improvements in the theory and exploit these to build a first prototype tool that can analyze timed systems with recursion.
Cite as

S. Akshay, Paul Gastin, Shankara Narayanan Krishna, and Ilias Sarkar. Towards an Efficient Tree Automata Based Technique for Timed Systems. In 28th International Conference on Concurrency Theory (CONCUR 2017). Leibniz International Proceedings in Informatics (LIPIcs), Volume 85, pp. 39:1-39:15, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2017)

Copy BibTex To Clipboard

@InProceedings{akshay_et_al:LIPIcs.CONCUR.2017.39,
  author =	{Akshay, S. and Gastin, Paul and Krishna, Shankara Narayanan and Sarkar, Ilias},
  title =	{{Towards an Efficient Tree Automata Based Technique for Timed Systems}},
  booktitle =	{28th International Conference on Concurrency Theory (CONCUR 2017)},
  pages =	{39:1--39:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-048-4},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{85},
  editor =	{Meyer, Roland and Nestmann, Uwe},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2017.39},
  URN =		{urn:nbn:de:0030-drops-78017},
  doi =		{10.4230/LIPIcs.CONCUR.2017.39},
  annote =	{Keywords: Timed automata, tree automata, pushdown systems, tree-width}
}
Document
DOI: 10.4230/LIPIcs.FSTTCS.2016.12
FO-Definable Transformations of Infinite Strings

Authors: Vrunda Dave, Shankara Narayanan Krishna, and Ashutosh Trivedi

Published in: LIPIcs, Volume 65, 36th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2016)

Abstract
The theory of regular and aperiodic transformations of finite strings has recently received a lot of interest. These classes can be equivalently defined using logic (Monadic second-order logic and first-order logic), two-way machines (regular two-way and aperiodic two-way transducers), and one-way register machines (regular streaming string and aperiodic streaming string transducers). These classes are known to be closed under operations such as sequential composition and regular (star-free) choice; and problems such as functional equivalence and type checking, are decidable for these classes. On the other hand, for infinite strings these results are only known for regular transformations: Alur, Filiot, and Trivedi studied transformations of infinite strings and introduced an extension of streaming string transducers over infinte strings and showed that they capture monadic second-order definable transformations for infinite strings. In this paper we extend their work to recover connection for infinite strings among first-order logic definable transformations, aperiodic two-way transducers, and aperiodic streaming string transducers.
Cite as

Vrunda Dave, Shankara Narayanan Krishna, and Ashutosh Trivedi. FO-Definable Transformations of Infinite Strings. In 36th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 65, pp. 12:1-12:14, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2016)

Copy BibTex To Clipboard

@InProceedings{dave_et_al:LIPIcs.FSTTCS.2016.12,
  author =	{Dave, Vrunda and Krishna, Shankara Narayanan and Trivedi, Ashutosh},
  title =	{{FO-Definable Transformations of Infinite Strings}},
  booktitle =	{36th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2016)},
  pages =	{12:1--12:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-027-9},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{65},
  editor =	{Lal, Akash and Akshay, S. and Saurabh, Saket and Sen, Sandeep},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSTTCS.2016.12},
  URN =		{urn:nbn:de:0030-drops-68476},
  doi =		{10.4230/LIPIcs.FSTTCS.2016.12},
  annote =	{Keywords: Transducers, FO-definability, Infinite Strings}
}
Document
DOI: 10.4230/LIPIcs.FSTTCS.2016.44
Mean-Payoff Games on Timed Automata

Authors: Shibashis Guha, Marcin Jurdzinski, Shankara Narayanan Krishna, and Ashutosh Trivedi

Published in: LIPIcs, Volume 65, 36th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2016)

Abstract
Mean-payoff games on timed automata are played on the infinite weighted graph of configurations of priced timed automata between two players - Player Min and Player Max - by moving a token along the states of the graph to form an infinite run. The goal of Player Min is to minimize the limit average weight of the run, while the goal of the Player Max is the opposite. Brenguier, Cassez, and Raskin recently studied a variation of these games and showed that mean-payoff games are undecidable for timed automata with five or more clocks. We refine this result by proving the undecidability of mean-payoff games with three clocks. On a positive side, we show the decidability of mean-payoff games on one-clock timed automata with binary price-rates. A key contribution of this paper is the application of dynamic programming based proof techniques applied in the context of average reward optimization on an uncountable state and action space.
Cite as

Shibashis Guha, Marcin Jurdzinski, Shankara Narayanan Krishna, and Ashutosh Trivedi. Mean-Payoff Games on Timed Automata. In 36th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 65, pp. 44:1-44:14, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2016)

Copy BibTex To Clipboard

@InProceedings{guha_et_al:LIPIcs.FSTTCS.2016.44,
  author =	{Guha, Shibashis and Jurdzinski, Marcin and Krishna, Shankara Narayanan and Trivedi, Ashutosh},
  title =	{{Mean-Payoff Games on Timed Automata}},
  booktitle =	{36th IARCS Annual Conference on Foundations of Software Technology and Theoretical Computer Science (FSTTCS 2016)},
  pages =	{44:1--44:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-027-9},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{65},
  editor =	{Lal, Akash and Akshay, S. and Saurabh, Saket and Sen, Sandeep},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSTTCS.2016.44},
  URN =		{urn:nbn:de:0030-drops-68797},
  doi =		{10.4230/LIPIcs.FSTTCS.2016.44},
  annote =	{Keywords: Timed Automata, Mean-Payoff Games, Controller-Synthesis}
}
Document
DOI: 10.4230/LIPIcs.CONCUR.2016.27
Analyzing Timed Systems Using Tree Automata

Authors: S. Akshay, Paul Gastin, and Shankara Narayanan Krishna

Published in: LIPIcs, Volume 59, 27th International Conference on Concurrency Theory (CONCUR 2016)

Abstract
Timed systems, such as timed automata, are usually analyzed using their operational semantics on timed words. The classical region abstraction for timed automata reduces them to (untimed) finite state automata with the same time-abstract properties, such as state reachability. We propose a new technique to analyze such timed systems using finite tree automata instead of finite word automata. The main idea is to consider timed behaviors as graphs with matching edges capturing timing constraints. Such graphs can be interpreted in trees opening the way to tree automata based techniques which are more powerful than analysis based on word automata. The technique is quite general and applies to many timed systems. In this paper, as an example, we develop the technique on timed pushdown systems, which have recently received considerable attention. Further, we also demonstrate how we can use it on timed automata and timed multi-stack pushdown systems (with boundedness restrictions).
Cite as

S. Akshay, Paul Gastin, and Shankara Narayanan Krishna. Analyzing Timed Systems Using Tree Automata. In 27th International Conference on Concurrency Theory (CONCUR 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 59, pp. 27:1-27:14, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2016)

Copy BibTex To Clipboard

@InProceedings{akshay_et_al:LIPIcs.CONCUR.2016.27,
  author =	{Akshay, S. and Gastin, Paul and Krishna, Shankara Narayanan},
  title =	{{Analyzing Timed Systems Using Tree Automata}},
  booktitle =	{27th International Conference on Concurrency Theory (CONCUR 2016)},
  pages =	{27:1--27:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-017-0},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{59},
  editor =	{Desharnais, Jos\'{e}e and Jagadeesan, Radha},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.CONCUR.2016.27},
  URN =		{urn:nbn:de:0030-drops-61775},
  doi =		{10.4230/LIPIcs.CONCUR.2016.27},
  annote =	{Keywords: Timed automata, tree automata, pushdown systems, tree-width}
}
Document
DOI: 10.4230/LIPIcs.MFCS.2016.8
Stochastic Timed Games Revisited

Authors: S. Akshay, Patricia Bouyer, Shankara Narayanan Krishna, Lakshmi Manasa, and Ashutosh Trivedi

Published in: LIPIcs, Volume 58, 41st International Symposium on Mathematical Foundations of Computer Science (MFCS 2016)

Abstract
Stochastic timed games (STGs), introduced by Bouyer and Forejt, naturally generalize both continuous-time Markov chains and timed automata by providing a partition of the locations between those controlled by two players (Player Box and Player Diamond) with competing objectives and those governed by stochastic laws. Depending on the number of players - 2, 1, or 0 - subclasses of stochastic timed games are often classified as 2 1/2-player, 1 1/2-player, and 1/2-player games where the 1/2 symbolizes the presence of the stochastic "nature" player. For STGs with reachability objectives it is known that 1 1/2-player one-clock STGs are decidable for qualitative objectives, and that 2 1/2-player three-clock STGs are undecidable for quantitative reachability objectives. This paper further refines the gap in this decidability spectrum. We show that quantitative reachability objectives are already undecidable for 1 1/2 player four-clock STGs, and even under the time-bounded restriction for 2 1/2-player five-clock STGs. We also obtain a class of 1 1/2, 2 1/2 player STGs for which the quantitative reachability problem is decidable.
Cite as

S. Akshay, Patricia Bouyer, Shankara Narayanan Krishna, Lakshmi Manasa, and Ashutosh Trivedi. Stochastic Timed Games Revisited. In 41st International Symposium on Mathematical Foundations of Computer Science (MFCS 2016). Leibniz International Proceedings in Informatics (LIPIcs), Volume 58, pp. 8:1-8:14, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2016)

Copy BibTex To Clipboard

@InProceedings{akshay_et_al:LIPIcs.MFCS.2016.8,
  author =	{Akshay, S. and Bouyer, Patricia and Krishna, Shankara Narayanan and Manasa, Lakshmi and Trivedi, Ashutosh},
  title =	{{Stochastic Timed Games Revisited}},
  booktitle =	{41st International Symposium on Mathematical Foundations of Computer Science (MFCS 2016)},
  pages =	{8:1--8:14},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-016-3},
  ISSN =	{1868-8969},
  year =	{2016},
  volume =	{58},
  editor =	{Faliszewski, Piotr and Muscholl, Anca and Niedermeier, Rolf},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.MFCS.2016.8},
  URN =		{urn:nbn:de:0030-drops-64985},
  doi =		{10.4230/LIPIcs.MFCS.2016.8},
  annote =	{Keywords: timed automata, stochastic games, two-counter machines}
}
Document
DOI: 10.4230/LITES-v003-i001-a003
Modeling Power Consumption and Temperature in TLM Models

Authors: Matthieu Moy, Claude Helmstetter, Tayeb Bouhadiba, and Florence Maraninchi

Published in: LITES, Volume 3, Issue 1 (2016). Leibniz Transactions on Embedded Systems, Volume 3, Issue 1

Abstract
Many techniques and tools exist to estimate the power consumption and the temperature map of a chip. These tools help the hardware designers develop power efficient chips in the presence of temperature constraints. For this task, the application can be ignored or at least abstracted by some high level scenarios; at this stage, the actual embedded software is generally not available yet.However, after the hardware is defined, the embedded software can still have a significant influence on the power consumption; i.e., two implementations of the same application can consume more or less power. Moreover, the actual software power manager ensuring the temperature constraints, usually by acting dynamically on the voltage and frequency, must itself be validated. Validating such power management policy requires a model of both actuators and sensors, hence a closed-loop simulation of the functional model with a non-functional one.In this paper, we present and compare several tools to simulate the power and thermal behavior of a chip together with its functionality. We explore several levels of abstraction and study the impact on the precision of the analysis.
Cite as

Matthieu Moy, Claude Helmstetter, Tayeb Bouhadiba, and Florence Maraninchi. Modeling Power Consumption and Temperature in TLM Models. In LITES, Volume 3, Issue 1 (2016). Leibniz Transactions on Embedded Systems, Volume 3, Issue 1, pp. 03:1-03:29, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2016)

Copy BibTex To Clipboard

@Article{moy_et_al:LITES-v003-i001-a003,
  author =	{Moy, Matthieu and Helmstetter, Claude and Bouhadiba, Tayeb and Maraninchi, Florence},
  title =	{{Modeling Power Consumption and Temperature in TLM Models}},
  booktitle =	{LITES, Volume 3, Issue 1 (2016)},
  pages =	{03:1--03:29},
  journal =	{Leibniz Transactions on Embedded Systems},
  ISSN =	{2199-2002},
  year =	{2016},
  volume =	{3},
  number =	{1},
  editor =	{Moy, Matthieu and Helmstetter, Claude and Bouhadiba, Tayeb and Maraninchi, Florence},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LITES-v003-i001-a003},
  doi =		{10.4230/LITES-v003-i001-a003},
  annote =	{Keywords: Power consumption, Temperature control, Virtual prototype, SystemC, Transactional modeling}
}
Document
DOI: 10.4230/LIPIcs.FSTTCS.2014.147
First-order Definable String Transformations

Authors: Emmanuel Filiot, Shankara Narayanan Krishna, and Ashutosh Trivedi

Published in: LIPIcs, Volume 29, 34th International Conference on Foundation of Software Technology and Theoretical Computer Science (FSTTCS 2014)

Abstract
The connection between languages defined by computational models and logic for languages is well-studied. Monadic second-order logic and finite automata are shown to closely correspond to each-other for the languages of strings, trees, and partial-orders. Similar connections are shown for first-order logic and finite automata with certain aperiodicity restriction. Courcelle in 1994 proposed a way to use logic to define functions over structures where the output structure is defined using logical formulas interpreted over the input structure. Engelfriet and Hoogeboom discovered the corresponding "automata connection" by showing that two-way generalised sequential machines capture the class of monadic-second order definable transformations. Alur and Cerny further refined the result by proposing a one-way deterministic transducer model with string variables - called the streaming string transducers - to capture the same class of transformations. In this paper we establish a transducer-logic correspondence for Courcelle's first-order definable string transformations. We propose a new notion of transition monoid for streaming string transducers that involves structural properties of both underlying input automata and variable dependencies. By putting an aperiodicity restriction on the transition monoids, we define a class of streaming string transducers that captures exactly the class of first-order definable transformations.
Cite as

Emmanuel Filiot, Shankara Narayanan Krishna, and Ashutosh Trivedi. First-order Definable String Transformations. In 34th International Conference on Foundation of Software Technology and Theoretical Computer Science (FSTTCS 2014). Leibniz International Proceedings in Informatics (LIPIcs), Volume 29, pp. 147-159, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2014)

Copy BibTex To Clipboard

@InProceedings{filiot_et_al:LIPIcs.FSTTCS.2014.147,
  author =	{Filiot, Emmanuel and Krishna, Shankara Narayanan and Trivedi, Ashutosh},
  title =	{{First-order Definable String Transformations}},
  booktitle =	{34th International Conference on Foundation of Software Technology and Theoretical Computer Science (FSTTCS 2014)},
  pages =	{147--159},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-939897-77-4},
  ISSN =	{1868-8969},
  year =	{2014},
  volume =	{29},
  editor =	{Raman, Venkatesh and Suresh, S. P.},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.FSTTCS.2014.147},
  URN =		{urn:nbn:de:0030-drops-48393},
  doi =		{10.4230/LIPIcs.FSTTCS.2014.147},
  annote =	{Keywords: First-order logic, streaming string transducers}
}
Document
DOI: 10.4230/LITES-v001-i002-a001
Blocking Optimality in Distributed Real-Time Locking Protocols

Authors: Björn Bernhard Brandenburg

Published in: LITES, Volume 1, Issue 2 (2014). Leibniz Transactions on Embedded Systems, Volume 1, Issue 2

Abstract
Lower and upper bounds on the maximum priority inversion blocking (pi-blocking) that is generally unavoidable in distributed multiprocessor real-time locking protocols (where resources may be accessed only from specific synchronization processors) are established. Prior work on suspension-based shared-memory multiprocessor locking protocols (which require resources to be accessible from all processors) has established asymptotically tight bounds of Ω(m) and Ω(n) maximum pi-blocking under suspension-oblivious and suspension-aware analysis, respectively, where m denotes the total number of processors and n denotes the number of tasks. In this paper, it is shown that, in the case of distributed semaphore protocols, there exist two different task allocation scenarios that give rise to distinct lower bounds. In the case of co-hosted task allocation, where application tasks may also be assigned to synchronization processors (i.e., processors hosting critical sections), Ω(Φ · n) maximum pi-blocking is unavoidable for some tasks under any locking protocol under both suspension-aware and suspension-oblivious schedulability analysis, where Φ denotes the ratio of the maximum response time to the shortest period. In contrast, in the case of disjoint task allocation (i.e., if application tasks may not be assigned to synchronization processors), only Ω(m) and Ω(n) maximum pi-blocking is fundamentally unavoidable under suspension-oblivious and suspension-aware analysis, respectively, as in the shared-memory case. These bounds are shown to be asymptotically tight with the construction of two new distributed real-time locking protocols that ensure O(m) and O(n) maximum pi-blocking under suspension-oblivious and suspension-aware analysis, respectively.
Cite as

Björn Bernhard Brandenburg. Blocking Optimality in Distributed Real-Time Locking Protocols. In LITES, Volume 1, Issue 2 (2014). Leibniz Transactions on Embedded Systems, Volume 1, Issue 2, pp. 01:1-01:22, Schloss Dagstuhl - Leibniz-Zentrum für Informatik (2014)

Copy BibTex To Clipboard

@Article{brandenburg:LITES-v001-i002-a001,
  author =	{Brandenburg, Bj\"{o}rn Bernhard},
  title =	{{Blocking Optimality in Distributed Real-Time Locking Protocols}},
  booktitle =	{LITES, Volume 1, Issue 2 (2014)},
  pages =	{01:1--01:22},
  journal =	{Leibniz Transactions on Embedded Systems},
  ISSN =	{2199-2002},
  year =	{2014},
  volume =	{1},
  number =	{2},
  editor =	{Brandenburg, Bj\"{o}rn Bernhard},
  publisher =	{Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{https://drops.dagstuhl.de/entities/document/10.4230/LITES-v001-i002-a001},
  doi =		{10.4230/LITES-v001-i002-a001},
  annote =	{Keywords: Distributed multiprocessor real-time systems, Real-time locking, Priority inversion, Blocking optimality}
}
  • Refine by Author
  • 7 Krishna, Shankara Narayanan
  • 4 Akshay, S.
  • 4 Trivedi, Ashutosh
  • 2 Clemente, Lorenzo
  • 2 Dave, Vrunda
  • Show More...

  • Refine by Classification
  • 4 Theory of computation → Timed and hybrid models
  • 2 Computer systems organization → Real-time systems
  • 2 Theory of computation → Automata over infinite objects
  • 1 Hardware → Chip-level power issues
  • 1 Security and privacy → Logic and verification
  • Show More...

  • Refine by Keyword
  • 5 Timed automata
  • 2 Timed Automata
  • 2 pushdown systems
  • 2 tree automata
  • 2 tree-width
  • Show More...

  • Refine by Type
  • 15 document

  • Refine by Publication Year
  • 5 2016
  • 3 2020
  • 3 2021
  • 2 2014
  • 1 2017
  • Show More...

Questions / Remarks / Feedback
X

Feedback for Dagstuhl Publishing


Thanks for your feedback!

Feedback submitted

Could not send message

Please try again later or send an E-mail
© 2023 Schloss Dagstuhl - LZI GmbH Imprint Privacy Contact