Jean-François Raskin

Bio: Jean-François Raskin is an academic researcher from Université libre de Bruxelles. The author has contributed to research in topics: Decidability & Markov decision process. The author has an hindex of 47, co-authored 293 publications receiving 7429 citations. Previous affiliations of Jean-François Raskin include Free University of Brussels & Université de Namur.

ω-Petri Nets: Algorithms and Complexity

Abstract: We introduce ω-Petri nets ωPN, an extension of plain Petri nets with ω-labeled input and output arcs, that is well-suited to analyse parametric concurrent systems with dynamic thread creation. Most techniques such as the Karp and Miller tree or the Rackoff technique that have been proposed in the setting of plain Petri nets do not apply directly to ωPN because ωPN define transition systems that have infinite branching. This motivates a thorough analysis of the computational aspects of ωPN. We show that an ωPN can be turned into a plain Petri net that allows us to recover the reachability set of the ωPN, but that does not preserve termination an ωPN terminates iff it admits no infinitely long execution. This yields complexity bounds for the reachability, boundedness, place boundedness and coverability problems on ωPN. We provide a practical algorithm to compute a coverability set of the ωPN and to decide termination by adapting the classical Karp and Miller tree construction. We also adapt the Rackoff technique to ωPN, to obtain the exact complexity of the termination problem. Finally, we consider the extension of ωPN with reset and transfer arcs, and show how this extension impacts the decidability and complexity of the aforementioned problems.

Optimal Values of Multidimensional Mean-Payoff Games

Abstract: In this paper, we study the set of thresholds that the protagonist can force in a zero-sum two-player multidimensional mean-payoff game. The set of maximal elements of such a set is called the Pareto curve, a classical tool to analyze trade-offs. As thresholds are vectors of real numbers in multiple dimensions, there exist usually an infinite number of such maximal elements. Our main results are as follow. First, we study the geometry of this set and show that it is definable as a finite union of convex sets given by linear inequations. Second, we provide a Σ2 P algorithm to decide if this set intersects a convex set defined by linear inequations, and we prove the optimality of our algorithm by providing a matching complexity lower bound for the problem. Furthermore, we show that, under natural assumptions, i.e. fixed number of dimensions and polynomially bounded weights in the game, the problem can be solved in deterministic polynomial time. Finally, we show that the Pareto curve can be effectively constructed, and under the former natural assumptions, this construction can be done in deterministic polynomial time.

Iterated Regret Minimization in Game Graphs

Abstract: Iterated regret minimization has been introduced recently by J.Y. Halpern and R. Pass in classical strategic games. For many games of interest, this new solution concept provides solutions that are judged more reasonable than solutions offered by traditional game concepts -- such as Nash equilibrium --. Although computing iterated regret on explicit matrix game is conceptually and computationally easy, nothing is known about computing the iterated regret on games whose matrices are defined implicitly using game tree, game DAG or, more generally game graphs. In this paper, we investigate iterated regret minimization for infinite duration two-player quantitative non-zero sum games played on graphs. We consider reachability objectives that are not necessarily antagonist. Edges are weighted by integers -- one for each player --, and the payoffs are defined by the sum of the weights along the paths. Depending on the class of graphs, we give either polynomial or pseudo-polynomial time algorithms to compute a strategy that minimizes the regret for a fixed player. We finally give algorithms to compute the strategies of the two players that minimize the iterated regret for trees, and for graphs with strictly positive weights only.

Compositional Algorithms for Succinct Safety Games

Abstract: We study the synthesis of circuits for succinct safety specifications given in the AIG format. We show how AIG safety specifications can be decomposed automatically into sub specifications. Then we propose symbolic compositional algorithms to solve the synthesis problem compositionally starting for the sub-specifications. We have evaluated the compositional algorithms on a set of benchmarks including those proposed for the first synthesis competition organised in 2014 by the Synthesis Workshop affiliated to the CAV conference. We show that a large number of benchmarks can be decomposed automatically and solved more efficiently with the compositional algorithms that we propose in this paper.

New algorithms and data structures for the emptiness problem of alternating automata

Abstract: This work studies new algorithms and data structures that are useful in the context of program verification. As computers have become more and more ubiquitous in our modern societies, an increasingly large number of computer-based systems are considered safety-critical. Such systems are characterized by the fact that a failure or a bug (computer error in the computing jargon) could potentially cause large damage, whether in loss of life, environmental damage, or economic damage. For safety-critical systems, the industrial software engineering community increasingly calls for using techniques which provide some formal assurance that a certain piece of software is correct.One of the most successful program verification techniques is model checking, in which programs are typically abstracted by a finite-state machine. After this abstraction step, properties (typically in the form of some temporal logic formula) can be checked against the finite-state abstraction, with the help of automated tools. Alternating automata play an important role in this context, since many temporal logics on words and trees can be efficiently translated into those automata. This property allows for the reduction of model checking to automata-theoretic questions and is called the automata-theoretic approach to model checking. In this work, we provide three novel approaches for the analysis (emptiness checking) of alternating automata over finite and infinite words. First, we build on the successful framework of antichains to devise new algorithms for LTL satisfiability and model checking, using alternating automata. These algorithms combine antichains with reduced ordered binary decision diagrams in order to handle the exponentially large alphabets of the automata generated by the LTL translation. Second, we develop new abstraction and refinement algorithms for alternating automata, which combine the use of antichains with abstract interpretation, in order to handle ever larger instances of alternating automata. Finally, we define a new symbolic data structure, coined lattice-valued binary decision diagrams that is particularly well-suited for the encoding of transition functions of alternating automata over symbolic alphabets. All of these works are supported with empirical evaluations that confirm the practical usefulness of our approaches. / Ce travail traite de l'etude de nouveaux algorithmes et structures de donnees dont l'usage est destine a la verification de programmes. Les ordinateurs sont de plus en plus presents dans notre vie quotidienne et, de plus en plus souvent, ils se voient confies des tâches de nature critique pour la securite. Ces systemes sont caracterises par le fait qu'une panne ou un bug (erreur en jargon informatique) peut avoir des effets potentiellement desastreux, que ce soit en pertes humaines, degâts environnementaux, ou economiques. Pour ces systemes critiques, les concepteurs de systemes industriels pronent de plus en plus l'usage de techniques permettant d'obtenir une assurance formelle de correction.Une des techniques de verification de programmes les plus utilisees est le model checking, avec laquelle les programmes sont typiquement abstraits par une machine a etats finis. Apres cette phase d'abstraction, des proprietes (typiquement sous la forme d'une formule de logique temporelle) peuvent etres verifiees sur l'abstraction a espace d'etats fini, a l'aide d'outils de verification automatises. Les automates alternants jouent un role important dans ce contexte, principalement parce que plusieurs logiques temporelle peuvent etres traduites efficacement vers ces automates. Cette caracteristique des automates alternants permet de reduire le model checking des logiques temporelles a des questions sur les automates, ce qui est appele l'approche par automates du model checking. Dans ce travail, nous etudions trois nouvelles approches pour l'analyse (le test du vide) desautomates alternants sur mots finis et infinis. Premierement, nous appliquons l'approche par antichaines (utilisee precedemment avec succes pour l'analyse d'automates) pour obtenir de nouveaux algorithmes pour les problemes de satisfaisabilite et du model checking de la logique temporelle lineaire, via les automates alternants.Ces algorithmes combinent l'approche par antichaines avec l'usage des ROBDD, dans le but de gerer efficacement la combinatoire induite par la taille exponentielle des alphabets d'automates generes a partir de LTL. Deuxiemement, nous developpons de nouveaux algorithmes d'abstraction et raffinement pour les automates alternants, combinant l'usage des antichaines et de l'interpretation abstraite, dans le but de pouvoir traiter efficacement des automates de grande taille. Enfin, nous definissons une nouvelle structure de donnees, appelee LVBDD (Lattice-Valued Binary Decision Diagrams), qui permet un encodage efficace des fonctions de transition des automates alternants sur alphabets symboliques. Tous ces travaux ont fait l'objet d'implementations et ont ete valides experimentalement.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Tools and Algorithms for the Construction and Analysis of Systems. Proc. TACAS 2009

Abstract: ing WS1S Systems to Verify Parameterized Networks . . . . . . . . . . . . 188 Kai Baukus, Saddek Bensalem, Yassine Lakhnech and Karsten Stahl FMona: A Tool for Expressing Validation Techniques over Infinite State Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204 J.-P. Bodeveix and M. Filali Transitive Closures of Regular Relations for Verifying Infinite-State Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 220 Bengt Jonsson and Marcus Nilsson Diagnostic and Test Generation Using Static Analysis to Improve Automatic Test Generation . . . . . . . . . . . . . 235 Marius Bozga, Jean-Claude Fernandez and Lucian Ghirvu Efficient Diagnostic Generation for Boolean Equation Systems . . . . . . . . . . . . 251 Radu Mateescu Efficient Model-Checking Compositional State Space Generation with Partial Order Reductions for Asynchronous Communicating Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 266 Jean-Pierre Krimm and Laurent Mounier Checking for CFFD-Preorder with Tester Processes . . . . . . . . . . . . . . . . . . . . . . . 283 Juhana Helovuo and Antti Valmari Fair Bisimulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299 Thomas A. Henzinger and Sriram K. Rajamani Integrating Low Level Symmetries into Reachability Analysis . . . . . . . . . . . . . 315 Karsten Schmidt Model-Checking Tools Model Checking Support for the ASM High-Level Language . . . . . . . . . . . . . . 331 Giuseppe Del Castillo and Kirsten Winter Table of

PDDL2.1: an extension to PDDL for expressing temporal planning domains

Abstract: In recent years research in the planning community has moved increasingly towards application of planners to realistic problems involving both time and many types of resources. For example, interest in planning demonstrated by the space research community has inspired work in observation scheduling, planetary rover exploration and spacecraft control domains. Other temporal and resource-intensive domains including logistics planning, plant control and manufacturing have also helped to focus the community on the modelling and reasoning issues that must be confronted to make planning technology meet the challenges of application. The International Planning Competitions have acted as an important motivating force behind the progress that has been made in planning since 1998. The third competition (held in 2002) set the planning community the challenge of handling time and numeric resources. This necessitated the development of a modelling language capable of expressing temporal and numeric properties of planning domains. In this paper we describe the language, PDDL2.1, that was used in the competition. We describe the syntax of the language, its formal semantics and the validation of concurrent plans. We observe that PDDL2.1 has considerable modelling power -- exceeding the capabilities of current planning technology -- and presents a number of important challenges to the research community.

Lazy abstraction

Abstract: One approach to model checking software is based on the abstract-check-refine paradigm: build an abstract model, then check the desired property, and if the check fails, refine the model and start over. We introduce the concept of lazy abstraction to integrate and optimize the three phases of the abstract-check-refine loop. Lazy abstraction continuously builds and refines a single abstract model on demand, driven by the model checker, so that different parts of the model may exhibit different degrees of precision, namely just enough to verify the desired property. We present an algorithm for model checking safety properties using lazy abstraction and describe an implementation of the algorithm applied to C programs. We also provide sufficient conditions for the termination of the method.