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15 results on '"Genest, Blaise"'

1. Classification among Hidden Markov Models

Author

Akshay, S., Bazille, Hugo, Fabre, Eric, Genest, Blaise, Department of Computer Science and Engineering [Bombay], Indian Institute of Technology Bombay (IIT Bombay), École normale supérieure - Rennes (ENS Rennes), SUpervision of large MOdular and distributed systems (SUMO), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-LANGAGE ET GÉNIE LOGICIEL (IRISA-D4), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes 1 (UR1), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique)

Subjects
060201 languages & linguistics, ComputingMethodologies_PATTERNRECOGNITION, 000 Computer science, knowledge, general works, 0602 languages and literature, Computer Science, [INFO.INFO-OH]Computer Science [cs]/Other [cs.OH], 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, 06 humanities and the arts, 02 engineering and technology, ComputingMilieux_MISCELLANEOUS
Abstract

An important task in AI is one of classifying an observation as belonging to one class among several (e.g. image classification). We revisit this problem in a verification context: given k partially observable systems modeled as Hidden Markov Models (also called labeled Markov chains), and an execution of one of them, can we eventually classify which system performed this execution, just by looking at its observations? Interestingly, this problem generalizes several problems in verification and control, such as fault diagnosis and opacity. Also, classification has strong connections with different notions of distances between stochastic models. In this paper, we study a general and practical notion of classifiers, namely limit-sure classifiers, which allow misclassification, i.e. errors in classification, as long as the probability of misclassification tends to 0 as the length of the observation grows. To study the complexity of several notions of classification, we develop techniques based on a simple but powerful notion of stationary distributions for HMMs. We prove that one cannot classify among HMMs iff there is a finite separating word from their stationary distributions. This provides a direct proof that classifiability can be checked in PTIME, as an alternative to existing proofs using separating events (i.e. sets of infinite separating words) for the total variation distance. Our approach also allows us to introduce and tackle new notions of classifiability which are applicable in a security context.

Published
2019
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2. Controlling a Population

Author

Bertrand, Nathalie, Dewaskar, Miheer, Genest, Blaise, Gimbert, Hugo, Institut de Radioprotection et de Sûreté Nucléaire (IRSN), Chennai Mathematical Institute [Inde], SUpervision of large MOdular and distributed systems (SUMO), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-LANGAGE ET GÉNIE LOGICIEL (IRISA-D4), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Laboratoire Bordelais de Recherche en Informatique (LaBRI), Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS), Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-CentraleSupélec-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Bretagne Sud (UBS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB), University of North Carolina [Chapel Hill] (UNC), University of North Carolina System (UNC), and ANR-13-BS02-0011,Stoch-MC,Modèles stochastiques: passage à l'échelle pour le Model Checking(2013)

Subjects
FOS: Computer and information sciences, Computer Science::Computer Science and Game Theory, 000 Computer science, knowledge, general works, [INFO.INFO-GT]Computer Science [cs]/Computer Science and Game Theory [cs.GT], Formal Languages and Automata Theory (cs.FL), [INFO.INFO-OH]Computer Science [cs]/Other [cs.OH], Computer Science - Formal Languages and Automata Theory, Systems and Control (eess.SY), [INFO.INFO-FL]Computer Science [cs]/Formal Languages and Automata Theory [cs.FL], Computer Science - Computer Science and Game Theory, Computer Science, FOS: Electrical engineering, electronic engineering, information engineering, Computer Science - Systems and Control, Computer Science and Game Theory (cs.GT)
Abstract

International audience; We introduce a new setting where a population of agents, each modelled by a finite-state system, are controlled uniformly: the controller applies the same action to every agent. The framework is largely inspired by the control of a biological system, namely a population of yeasts, where the controller may only change the environment common to all cells. We study a synchronisation problem for such populations: no matter how individual agents react to the actions of the controller , the controller aims at driving all agents synchronously to a target state. The agents are naturally represented by a non-deterministic finite state automaton (NFA), the same for every agent, and the whole system is encoded as a 2-player game. The first player (Controller) chooses actions, and the second player (Agents) resolves non-determinism for each agent. The game with m agents is called the m-population game. This gives rise to a parameterized control problem (where control refers to 2 player games), namely the population control problem: can Controller control the m-population game for all m ∈ N whatever Agents does? In this paper, we prove that the population control problem is decidable, and it is a EXPTIME-complete problem. As far as we know, this is one of the first results on parameterized control. Our algorithm, not based on cutoff techniques, produces winning strategies which are symbolic, that is, they do not need to count precisely how the population is spread between states. We also show that if there is no winning strategy, then there is a population size M such that Controller wins the m-population game if and only if m $≤ M$ . Surprisingly, M can be doubly exponential in the number of states of the NFA, with tight upper and lower bounds.

Published
2017

3. On Regularity of unary Probabilistic Automata

Author

Akshay, S., Genest, Blaise, Karelovic, Bruno, Vyas, Nikhil, Department of Computer Science and Engineering [Bombay], Indian Institute of Technology Bombay (IIT Bombay), SUpervision of large MOdular and distributed systems (SUMO), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-LANGAGE ET GÉNIE LOGICIEL (IRISA-D4), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de Recherche en Informatique et en Automatique (Inria)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Télécom Bretagne-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Université de Bretagne Sud (UBS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Laboratoire d'informatique Algorithmique : Fondements et Applications (LIAFA), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), ANR-13-BS02-0011,Stoch-MC,Modèles stochastiques: passage à l'échelle pour le Model Checking(2013), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Institut National de Recherche en Informatique et en Automatique (Inria)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Bretagne Sud (UBS)-École normale supérieure - Rennes (ENS Rennes)-Télécom Bretagne-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)

Subjects
000 Computer science, knowledge, general works, 010201 computation theory & mathematics, Computer Science, [INFO.INFO-OH]Computer Science [cs]/Other [cs.OH], 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, 0102 computer and information sciences, 02 engineering and technology, 01 natural sciences, Computer Science::Formal Languages and Automata Theory
Abstract

International audience; The quantitative verification of Probabilistic Automata (PA) is undecidable in general. Unary PA are a simpler model where the choice of action is fixed. Still, the quantitative verification problem is open and known to be as hard as Skolem's problem, a problem on linear recurrence sequences, whose decidability is open for at least 40 years. In this paper, we approach this problem by studying the languages generated by unary PAs (as defined below), whose regularity would entail the decidability of quantitative verification. Given an initial distribution, we represent the trajectory of a unary PA over time as an infinite word over a finite alphabet, where the n th letter represents a probability range after n steps. We extend this to a language of trajectories (a set of words), one trajectory for each initial distribution from a (possibly infinite) set. We show that if the eigenvalues of the transition matrix associated with the unary PA are all distinct positive real numbers, then the language is effectively regular. Further, we show that this result is at the boundary of regularity, as non-regular languages can be generated when the restrictions are even slightly relaxed. The regular representation of the language allows us to reason about more general properties, e.g., robustness of a regular property in a neighbourhood around a given distribution.

Published
2016

4. Minimal Disclosure in Partially Observable Markov Decision Processes

Author

Bertrand, Nathalie, Genest, Blaise, Verification models and techniques applied to testing and control of reactive systems (VERTECS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Image & Pervasive Access Lab (IPAL), National University of Singapore (NUS)-MATHEMATIQUES, SCIENCES ET TECHNOLOGIES DE L'INFORMATION ET DE LA COMMUNICATION (UJF)-Agency for science, technology and research [Singapore] (A*STAR)-Centre National de la Recherche Scientifique (CNRS)-Institute for Infocomm Research - I²R [Singapore], and National University of Singapore (NUS)-Agency for science, technology and research [Singapore] (A*STAR)-Centre National de la Recherche Scientifique (CNRS)-Institute for Infocomm Research - I²R [Singapore]

Subjects
000 Computer science, knowledge, general works, 010201 computation theory & mathematics, Computer Science, [INFO.INFO-OH]Computer Science [cs]/Other [cs.OH], 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, 0102 computer and information sciences, 02 engineering and technology, 01 natural sciences
Abstract

International audience; For security and efficiency reasons, most systems do not give the users a full access to their information. One key specification formalism for these systems are the so called Partially Observable Markov Decision Processes (POMDP for short), which have been extensively studied in several research communities, among which AI and model-checking. In this paper we tackle the problem of the minimal information a user needs at runtime to achieve a simple goal, modeled as reaching an objective with probability one. More precisely, to achieve her goal, the user can at each step either choose to use the partial information, or pay a fixed cost and receive the full information. The natural question is then to minimize the cost the user needs to fulfill her objective. This optimization question gives rise to two different problems, whether we consider to minimize the worst case cost, or the average cost. On the one hand, concerning the worst case cost, we show that efficient techniques from the model checking community can be adapted to compute the optimal worst case cost and give optimal strategies for the users. On the other hand, we show that the optimal average price (a question typically considered in the AI community) cannot be computed in general, nor can it be approximated in polynomial time even up to a large approximation factor.

Published
2011

5. Verifying Recursive Active Documents with Positive Data Tree Rewriting

Author

Genest, Blaise, Muscholl, Anca, Wu, Zhilin, Distributed and Iterative Algorithms for the Management of Telecommunications Systems (DISTRIBCOM), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria), Laboratoire Bordelais de Recherche en Informatique (LaBRI), Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Inria Rennes – Bretagne Atlantique, Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Université Sciences et Technologies - Bordeaux 1-Université Bordeaux Segalen - Bordeaux 2, and Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)

Subjects
FOS: Computer and information sciences, 000 Computer science, knowledge, general works, [INFO.INFO-DB]Computer Science [cs]/Databases [cs.DB], Other Computer Science (cs.OH), [INFO.INFO-OH]Computer Science [cs]/Other [cs.OH], Databases (cs.DB), 0102 computer and information sciences, 02 engineering and technology, 01 natural sciences, TheoryofComputation_MATHEMATICALLOGICANDFORMALLANGUAGES, Computer Science - Databases, Computer Science - Other Computer Science, 010201 computation theory & mathematics, Computer Science::Logic in Computer Science, Computer Science, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Computer Science::Databases
Abstract

This paper considers a tree-rewriting framework for modeling documents evolving through service calls. We focus on the automatic verification of properties of documents that may contain data from an infinite domain. We establish the boundaries of decidability: while verifying documents with recursive calls is undecidable, we obtain decidability as soon as either documents are in the positive-bounded fragment (while calls are unrestricted), or when there is a bound on the number of service calls (bounded model-checking of unrestricted documents). In the latter case, the complexity is NexpTime-complete. Our data tree-rewriting framework resembles Guarded Active XML, a platform handling XML repositories that evolve through web services. The model here captures the basic features of Guarded Active XML and extends it by node renaming and subtree deletion.

Published
2010

6. Determinacy and Decidability of Reachability Games with Partial Observation on Both Sides

Author

Bertrand, Nathalie, Genest, Blaise, Gimbert, Hugo, Verification models and techniques applied to testing and control of reactive systems (VERTECS), Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), Distributed and Iterative Algorithms for the Management of Telecommunications Systems (DISTRIBCOM), Institut de Recherche en Informatique et Systèmes Aléatoires (IRISA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Inria Rennes – Bretagne Atlantique, Institut National de Recherche en Informatique et en Automatique (Inria), Laboratoire Bordelais de Recherche en Informatique (LaBRI), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB), ERTN GAMES, ANR-06-SETI-0003,DOTS,Systèmes distribués, ouverts et temporisés(2006), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Inria Rennes – Bretagne Atlantique, and Université de Bordeaux (UB)-École Nationale Supérieure d'Électronique, Informatique et Radiocommunications de Bordeaux (ENSEIRB)-Centre National de la Recherche Scientifique (CNRS)

Subjects
FOS: Computer and information sciences, Computer Science::Computer Science and Game Theory, [INFO.INFO-GT]Computer Science [cs]/Computer Science and Game Theory [cs.GT], Computer Science - Computer Science and Game Theory, Computer Science::Logic in Computer Science, games with partial observation, Mathematics::Metric Geometry, computer science, Computer Science::Formal Languages and Automata Theory, reachability games, Computer Science and Game Theory (cs.GT)
Abstract

We prove two determinacy and decidability results about two-players stochastic reachability games with partial observation on both sides and finitely many states, signals and actions.

Published
2008

7. Detecting Races in Ensembles of Message Sequence Charts.

Author

Hutchison, David, Kanade, Takeo, Kittler, Josef, Kleinberg, Jon M., Mattern, Friedemann, Mitchell, John C., Naor, Moni, Nierstrasz, Oscar, Rangan, C. Pandu, Steffen, Bernhard, Sudan, Madhu, Terzopoulos, Demetri, Tygar, Doug, Vardi, Moshe Y., Weikum, Gerhard, Grumberg, Orna, Huth, Michael, Elkind, Edith, Genest, Blaise, and Peled, Doron

Abstract

The analysis of message sequence charts (MSCs) is highly important in preventing common problems in communication protocols. Detecting race conditions, i.e., possible discrepancies in event order, was studied for a single MSC and for MSC graphs (a graph where each node consists of a single MSC, also called HMSC). For the former case, this problem can be solved in quadratic time, while for the latter case it was shown to be undecidable. However, the prevailing real-life situation is that a collection of MSCs, called here an ensemble, describing the different possible scenarios of the system behavior, is provided, rather than a single MSC or an MSC graph. For an ensemble of MSCs, a potential race condition in one of its MSCs can be compensated by another MSC in which the events occur in a different order. We provide a polynomial algorithm for detecting races in an ensemble. On the other hand, we show that in order to prevent races, the size of an ensemble may have to grow exponentially with the number of messages. Also, we initiate the formal study of the standard MSC coregion construct, which is used to relax the order among events of a process. We show that by using this construct, we can provide more compact race-free ensembles; however, detecting races becomes NP-complete. [ABSTRACT FROM AUTHOR]

Published
2007
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8. Causal Message Sequence Charts.

Author

Hutchison, David, Kanade, Takeo, Kittler, Josef, Kleinberg, Jon M., Mattern, Friedemann, Mitchell, John C., Naor, Moni, Nierstrasz, Oscar, Pandu Rangan, C., Steffen, Bernhard, Sudan, Madhu, Terzopoulos, Demetri, Tygar, Doug, Vardi, Moshe Y., Weikum, Gerhard, Caires, Luís, Vasconcelos, Vasco T., Gazagnaire, Thomas, Genest, Blaise, and Hélouët, Loïc

Abstract

Scenario languages based on Message Sequence Charts (MSCs) and related notations have been widely studied in the last decade [14,13,2,9,6,12,8]. The high expressive power of scenarios renders many basic problems concerning these languages undecidable. The most expressive class for which several problems are known to be decidable is one which possesses a behavioral property called "existentially bounded". However, scenarios outside this class are frequently exhibited by asynchronous distributed systems such as sliding window protocols. We propose here an extension of MSCs called Causal Message Sequence Charts, which preserves decidability without requiring existential bounds. Interestingly, it can also model scenarios from sliding window protocols. We establish the expressive power and complexity of decision procedures for various subclasses of Causal Message Sequence Charts. [ABSTRACT FROM AUTHOR]

Published
2007
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9. Constructing Exponential-Size Deterministic Zielonka Automata.

Author

Genest, Blaise, Muscholl, Anca, Bugliesi, Michele, Preneel, Bart, Sassone, Vladimiro, and Wegener, Ingo

Abstract

The well-known algorithm of Zielonka describes how to transform automatically a sequential automaton into a deterministic asynchronous trace automaton. In this paper, we improve the construction of deterministic asynchronous automata from finite state automaton. Our construction improves the well-known construction in that the size of the asynchronous automaton is simply exponential in both the size of the sequential automaton and the number of processes. In contrast, Zielonka’s algorithm gives an asynchronous automaton that is doubly exponential in the number of processes (and simply exponential in the size of the automaton). [ABSTRACT FROM AUTHOR]

Published
2006
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10. Grey-Box Checking.

Author

Najm, Elie, Pradat-Peyre, Jean François, Donzeau-Gouge, Véronique Viguié, Elkind, Edith, Genest, Blaise, Peled, Doron, and Hongyang Qu

Abstract

There are many cases where we want to verify a system that does not have a usable formal model: the model may be missing, out of date, or simply too big to be used. A possible method is to analyze the system while learning the model (black box checking). However, learning may be an expensive task, thus it needs to be guided, e.g., using the checked property or an inaccurate model (adaptive model checking). In this paper, we consider the case where some of the system components are completely specified (white boxes), while others are unknown (black boxes), giving rise to a grey box system. We provide algorithms and lower bounds, as well as experimental results for this model. [ABSTRACT FROM AUTHOR]

Published
2006
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11. On Implementation of Global Concurrent Systems with Local Asynchronous Controllers.

Author

Abadi, Martín, De Alfaro, Luca, and Genest, Blaise

Abstract

The classical modelization of concurrent system behaviors is based on observing execution sequences of global states. This model is intuitively simple and enjoys a variety of mathematical tools, e.g. finite automata, helping verifying concurrent systems. On the other hand, parallel composition of local controllers are needed when dealing with the actual implementation of concurrent models. A well known tool for turning global observation into local controllers is Zielonka's theorem, and its derivatives. We give here another algorithm, simpler and cheaper than Zielonka's theorem, in the case where the events observed do not include communication but only local asynchronous actions. In a developer point of view, it means that she does not have to explicitly specify the messages needed, which will be added (if allowed) automatically by the implementation algorithm. [ABSTRACT FROM AUTHOR]

Published
2005
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12. Snapshot Verification.

Author

Halbwachs, Nicolas, Zuck, Lenore D., Genest, Blaise, Kuske, Dietrich, Muscholl, Anca, and Peled, Doron

Abstract

The classical model for concurrent systems is based on observing execution sequences of global states, separated from each other by atomic transitions. This model is intuitively simple and enjoys a variety of mathematical tools, e.g., finite automata and linear temporal logic, and algorithms that can be applied in order to test and verify concurrent systems. Although this model is sufficient for most frequently used validation tasks, some phenomena of concurrent systems are difficult to express using its related formalisms. In particular, not all the global states (snapshots) related to an execution appear on a particular execution sequence; some appear on equivalent sequences. Previous attempts to move into formalisms that are based on a more detailed model of execution, e.g,. the causality based model, resulted in specification formalisms with inherently high complexity verification algorithms. We study here verification problems that involve allowing the execution sequences model to observe past global states from equivalent executions. We show various algorithms and complexity results related to our extension of the interleaving model. [ABSTRACT FROM AUTHOR]

Published
2005

13. Compositional Message Sequence Charts (CMSCs) Are Better to Implement Than MSCs.

Author

Halbwachs, Nicolas, Zuck, Lenore D., and Genest, Blaise

Abstract

Communicating Finite States Machines (CFMs) and Message Sequence Graphs (MSC-graphs for short) are two popular specification formalisms for communicating systems. MSC-graphs capture requirements (scenarios), hence they are the starting point of the design process. Implementing an MSC-graph means obtaining an equivalent deadlock-free CFM, since CFMs correspond to distributed message-passing algorithms. Several partial answers for the implementation have been proposed. E.g., local-choice MSC-graphs form a subclass of deadlock-free CFM: Testing equivalence with some local-choice MSC-graph is thus a partial answer to the implementation problem. Using Compositional MSCs, we propose a new algorithm which captures more implementable models than with MSCs. Furthermore, the size of the implementation is reduced by one exponential. [ABSTRACT FROM AUTHOR]

Published
2005

14. Quasi-static scheduling of communicating tasks

Author

Darondeau, Philippe, Genest, Blaise, Thiagarajan, P.S., and Yang, Shaofa

Subjects
*COMPUTER scheduling, *EMBEDDED computer systems, *COMPUTER simulation, *SEQUENTIAL processing (Computer science), *COMPUTER science, *PETRI nets, *GRAPHIC methods
Abstract

Abstract: Good scheduling policies for distributed embedded applications are required for meeting hard real time constraints and for optimizing the use of computational resources. We study the quasi-static scheduling problem in which (uncontrollable) control flow branchings can influence scheduling decisions at run time. Our abstracted distributed task model consists of a network of sequential processes that communicate via point-to-point buffers. In each round, the task gets activated by a request from the environment. When the task has finished computing the required responses, it reaches a pre-determined configuration and is ready to receive a new request from the environment. For such systems, we prove that determining the existence of a scheduling policy that guarantees upper bounds on buffer capacities is undecidable. However, we show that the problem is decidable for the important subclass of “data-branching” systems in which control flow branchings are exclusively due to data-dependent internal choices made by the sequential components. This decidability result exploits ideas derived from the Karp and Miller coverability tree for Petri nets as well as the existential boundedness notion of languages of message sequence charts. [ABSTRACT FROM AUTHOR]

Published
2010
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15. On commutativity based Edge Lean search.

Author

Bošnački, Dragan, Elkind, Edith, Genest, Blaise, and Peled, Doron

Subjects
COMMUTATIVE algebra, ALGEBRA, COMPUTER science, ARTIFICIAL intelligence, MATHEMATICS
Abstract

The problem of state space search is fundamental to many areas of computer science, such as, e.g., AI and formal methods. Often, the state space to be searched is huge, so optimizing the search is an important issue. In this paper, we consider the problem of visiting all states in the setting where transitions between states are generated by actions, and the (reachable) states are not known in advance. Some of the actions may commute, i.e., they result in the same state for every order in which they are taken. We show how to use commutativity to achieve full coverage of the states, while traversing a relatively small number of edges. [ABSTRACT FROM AUTHOR]

Published
2009
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