212 research outputs found
A unified view of parameterized verification of abstract models of broadcast communication
We give a unified view of different parameterized models of concurrent and distributed systems with broadcast communication based on transition systems. Based on the resulting formal models, we discuss related verification methods and tools based on abstractions and symbolic state exploration
Parameterized verification
The goal of parameterized verification is to prove the correctness of a system specification regardless of the number of its components. The problem is of interest in several different areas: verification of hardware design, multithreaded programs, distributed systems, and communication protocols. The problem is undecidable in general. Solutions for restricted classes of systems and properties have been studied in areas like theorem proving, model checking, automata and logic, process algebra, and constraint solving. In this introduction to the special issue, dedicated to a selection of works from the Parameterized Verification workshop PV \u201914 and PV \u201915, we survey some of the works developed in this research area
Asymptotic behaviour in temporal logic
International audienceno abstrac
Computer Aided Verification
This open access two-volume set LNCS 11561 and 11562 constitutes the refereed proceedings of the 31st International Conference on Computer Aided Verification, CAV 2019, held in New York City, USA, in July 2019. The 52 full papers presented together with 13 tool papers and 2 case studies, were carefully reviewed and selected from 258 submissions. The papers were organized in the following topical sections: Part I: automata and timed systems; security and hyperproperties; synthesis; model checking; cyber-physical systems and machine learning; probabilistic systems, runtime techniques; dynamical, hybrid, and reactive systems; Part II: logics, decision procedures; and solvers; numerical programs; verification; distributed systems and networks; verification and invariants; and concurrency
Contribution to the verification of timed automata (determinization, quantitative verification and reachability in networks of automata)
Cette thĂšse porte sur la vĂ©rification des automates temporisĂ©s, un modĂšle bien Ă©tabli pour les systĂšmes temps-rĂ©els. La thĂšse est constituĂ©e de trois parties. La premiĂšre est dĂ©diĂ©e Ă la dĂ©terminisation des automates temporisĂ©s, problĂšme qui n'a pas de solution en gĂ©nĂ©ral. Nous proposons une mĂ©thode approchĂ©e (sur-approximation, sous-approximation, mĂ©lange des deux) fondĂ©e sur la construction d'un jeu de sĂ»retĂ©. Cette mĂ©thode amĂ©liore les approches existantes en combinant leurs avantages respectifs. Nous appliquons ensuite cette mĂ©thode de dĂ©terminisation Ă la gĂ©nĂ©ration automatique de tests de conformitĂ©. Dans la seconde partie, nous prenons en compte des aspects quantitatifs des systĂšmes temps-rĂ©el grĂące Ă une notion de frĂ©quence des Ă©tats acceptants dans une exĂ©cution d'un automate temporisĂ©. Plus prĂ©cisĂ©ment, la frĂ©quence d'une exĂ©cution est la proportion de temps passĂ©e dans les Ă©tats acceptants. Nous intĂ©ressons alors Ă l'ensemble des frĂ©quences des exĂ©cutions d'un automate temporisĂ© pour Ă©tudier, par exemple, le vide de langages seuils. Nous montrons ainsi que les bornes de l'ensemble des frĂ©quences sont calculables pour deux classes d'automates temporisĂ©s. D'une part, les bornes peuvent ĂȘtre calculĂ©es en espace logarithmique par une procĂ©dure non-dĂ©terministe dans les automates temporisĂ©s Ă une horloge. D'autre part, elles peuvent ĂȘtre calculĂ©es en espace polynomial dans les automates temporisĂ©s Ă plusieurs horloges ne contenant pas de cycles forçant la convergence d'horloges. Finalement, nous Ă©tudions le problĂšme de l'accessibilitĂ© des Ă©tats acceptants dans des rĂ©seaux d'automates temporisĂ©s qui communiquent via des files FIFO. Nous considĂ©rons tout d'abord des automates temporisĂ©s Ă temps discret, et caractĂ©risons les topologies de rĂ©seaux pour lesquelles l'accessibilitĂ© est dĂ©cidable. Cette caractĂ©risation est ensuite Ă©tendue aux automates temporisĂ©s Ă temps continu.This thesis is about verification of timed automata, a well-established model for real time systems. The document is structured in three parts. The first part is dedicated to the determinization of timed automata, a problem which has no solution in general. We propose an approximate (over-approximation/under-approximation/mix) method based on the construction of a safety game. This method improves both existing approaches by combining their respective advantages. Then, we apply this determinization approach to the generation of conformance tests. In the second part, we take into account quantitative aspects of real time systems thanks to a notion of frequency of accepting states along executions of timed automata. More precisely, the frequency of a run is the proportion of time elapsed in accepting states. Then, we study the set of frequencies of runs of a timed automaton in order to decide, for example, the emptiness of threshold languages. We thus prove that the bounds of the set of frequencies are computable for two classes of timed automata. On the one hand, we prove that bounds are computable in logarithmic space by a non-deterministic procedure in one-clock timed automata. On the other hand, they can be computed in polynomial space in timed automata with several clocks, but having no cycle that forces the convergence between clocks. Finally, we study the reachability problem in networks of timed automata communicating through FIFO channels. We first consider dicrete timed automata, and characterize topologies of networks for which reachability is decidable. Then, this characterization is extended to dense-time automata.RENNES1-Bibl. Ă©lectronique (352382106) / SudocSudocFranceF
Computer Aided Verification
This open access two-volume set LNCS 11561 and 11562 constitutes the refereed proceedings of the 31st International Conference on Computer Aided Verification, CAV 2019, held in New York City, USA, in July 2019. The 52 full papers presented together with 13 tool papers and 2 case studies, were carefully reviewed and selected from 258 submissions. The papers were organized in the following topical sections: Part I: automata and timed systems; security and hyperproperties; synthesis; model checking; cyber-physical systems and machine learning; probabilistic systems, runtime techniques; dynamical, hybrid, and reactive systems; Part II: logics, decision procedures; and solvers; numerical programs; verification; distributed systems and networks; verification and invariants; and concurrency
When are Stochastic Transition Systems Tameable?
A decade ago, Abdulla, Ben Henda and Mayr introduced the elegant concept of
decisiveness for denumerable Markov chains [1]. Roughly speaking, decisiveness
allows one to lift most good properties from finite Markov chains to
denumerable ones, and therefore to adapt existing verification algorithms to
infinite-state models. Decisive Markov chains however do not encompass
stochastic real-time systems, and general stochastic transition systems (STSs
for short) are needed. In this article, we provide a framework to perform both
the qualitative and the quantitative analysis of STSs. First, we define various
notions of decisiveness (inherited from [1]), notions of fairness and of
attractors for STSs, and make explicit the relationships between them. Then, we
define a notion of abstraction, together with natural concepts of soundness and
completeness, and we give general transfer properties, which will be central to
several verification algorithms on STSs. We further design a generic
construction which will be useful for the analysis of {\omega}-regular
properties, when a finite attractor exists, either in the system (if it is
denumerable), or in a sound denumerable abstraction of the system. We next
provide algorithms for qualitative model-checking, and generic approximation
procedures for quantitative model-checking. Finally, we instantiate our
framework with stochastic timed automata (STA), generalized semi-Markov
processes (GSMPs) and stochastic time Petri nets (STPNs), three models
combining dense-time and probabilities. This allows us to derive decidability
and approximability results for the verification of these models. Some of these
results were known from the literature, but our generic approach permits to
view them in a unified framework, and to obtain them with less effort. We also
derive interesting new approximability results for STA, GSMPs and STPNs.Comment: 77 page
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