334 research outputs found
Tools and Algorithms for the Construction and Analysis of Systems
This book is Open Access under a CC BY licence. The LNCS 11427 and 11428 proceedings set constitutes the proceedings of the 25th International Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2019, which took place in Prague, Czech Republic, in April 2019, held as part of the European Joint Conferences on Theory and Practice of Software, ETAPS 2019. The total of 42 full and 8 short tool demo papers presented in these volumes was carefully reviewed and selected from 164 submissions. The papers are organized in topical sections as follows: Part I: SAT and SMT, SAT solving and theorem proving; verification and analysis; model checking; tool demo; and machine learning. Part II: concurrent and distributed systems; monitoring and runtime verification; hybrid and stochastic systems; synthesis; symbolic verification; and safety and fault-tolerant systems
Recent advances in petri nets and concurrency
CEUR Workshop Proceeding
Vérification efficace de systèmes à compteurs à l'aide de relaxations
Abstract : Counter systems are popular models used to reason about systems in various fields such as the analysis of concurrent or distributed programs and the discovery and verification of business processes. We study well-established problems on various classes of counter systems. This thesis focusses on three particular systems, namely Petri nets, which are a type of model for discrete systems with concurrent and sequential events, workflow nets, which form a subclass of Petri nets that is suited for modelling and reasoning about business processes, and continuous one-counter automata, a novel model that combines continuous semantics with one-counter automata. For Petri nets, we focus on reachability and coverability properties. We utilize directed search algorithms, using relaxations of Petri nets as heuristics, to obtain novel semi-decision algorithms for reachability and coverability, and positively evaluate a prototype implementation. For workflow nets, we focus on the problem of soundness, a well-established correctness notion for such nets. We precisely characterize the previously widely-open complexity of three variants of soundness. Based on our insights, we develop techniques to verify soundness in practice, based on reachability relaxation of Petri nets. Lastly, we introduce the novel model of continuous one-counter automata. This model is a natural variant of one-counter automata, which allows reasoning in a hybrid manner combining continuous and discrete elements. We characterize the exact complexity of the reachability problem in several variants of the model.Les systèmes à compteurs sont des modèles utilisés afin de raisonner sur les systèmes
de divers domaines tels l’analyse de programmes concurrents ou distribués, et
la découverte et la vérification de systèmes d’affaires. Nous étudions des problèmes
bien établis de différentes classes de systèmes à compteurs. Cette thèse se penche sur
trois systèmes particuliers : les rĂ©seaux de Petri, qui sont un type de modèle pour les systèmes discrets Ă
événements concurrents et séquentiels ; les « réseaux de processus », qui forment une sous-classe des réseaux de Petri
adaptée à la modélisation et au raisonnement des processus d’affaires ; les automates continus à un compteur, un nouveau modèle qui combine une
sémantique continue à celles des automates à un compteur.
Pour les réseaux de Petri, nous nous concentrons sur les propriétés d’accessibilité
et de couverture. Nous utilisons des algorithmes de parcours de graphes, avec
des relaxations de réseaux de Petri comme heuristiques, afin d’obtenir de nouveaux
algorithmes de semi-décision pour l’accessibilité et la couverture, et nous évaluons
positivement un prototype.
Pour les «réseaux de processus», nous nous concentrons sur le problème de validité,
une notion de correction bien établie pour ces réseaux. Nous caractérisions
précisément la complexité calculatoire jusqu’ici largement ouverte de trois variantes
du problème de validité. En nous basant sur nos résultats, nous développons des techniques
pour vérifier la validité en pratique, à l’aide de relaxations d’accessibilité dans
les réseaux de Petri. Enfin, nous introduisons le nouveau modèle d’automates continus à un compteur. Ce modèle est une variante naturelle des automates à un compteur, qui permet de
raisonner de manière hybride en combinant des éléments continus et discrets. Nous
caractérisons la complexité exacte du problème d’accessibilité dans plusieurs variantes
du modèle
Monotonic Abstraction Techniques: from Parametric to Software Model Checking
Monotonic abstraction is a technique introduced in model checking
parameterized distributed systems in order to cope with transitions containing
global conditions within guards. The technique has been re-interpreted in a
declarative setting in previous papers of ours and applied to the verification
of fault tolerant systems under the so-called "stopping failures" model. The
declarative reinterpretation consists in logical techniques (quantifier
relativizations and, especially, quantifier instantiations) making sense in a
broader context. In fact, we recently showed that such techniques can
over-approximate array accelerations, so that they can be employed as a
meaningful (and practically effective) component of CEGAR loops in software
model checking too.Comment: In Proceedings MOD* 2014, arXiv:1411.345
ADAM: Analysis of Discrete Models of Biological Systems Using Computer Algebra
Background: Many biological systems are modeled qualitatively with discrete
models, such as probabilistic Boolean networks, logical models, Petri nets, and
agent-based models, with the goal to gain a better understanding of the system.
The computational complexity to analyze the complete dynamics of these models
grows exponentially in the number of variables, which impedes working with
complex models. Although there exist sophisticated algorithms to determine the
dynamics of discrete models, their implementations usually require
labor-intensive formatting of the model formulation, and they are oftentimes
not accessible to users without programming skills. Efficient analysis methods
are needed that are accessible to modelers and easy to use. Method: By
converting discrete models into algebraic models, tools from computational
algebra can be used to analyze their dynamics. Specifically, we propose a
method to identify attractors of a discrete model that is equivalent to solving
a system of polynomial equations, a long-studied problem in computer algebra.
Results: A method for efficiently identifying attractors, and the web-based
tool Analysis of Dynamic Algebraic Models (ADAM), which provides this and other
analysis methods for discrete models. ADAM converts several discrete model
types automatically into polynomial dynamical systems and analyzes their
dynamics using tools from computer algebra. Based on extensive experimentation
with both discrete models arising in systems biology and randomly generated
networks, we found that the algebraic algorithms presented in this manuscript
are fast for systems with the structure maintained by most biological systems,
namely sparseness, i.e., while the number of nodes in a biological network may
be quite large, each node is affected only by a small number of other nodes,
and robustness, i.e., small number of attractors
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
Model Checking Linear Logic Specifications
The overall goal of this paper is to investigate the theoretical foundations
of algorithmic verification techniques for first order linear logic
specifications. The fragment of linear logic we consider in this paper is based
on the linear logic programming language called LO enriched with universally
quantified goal formulas. Although LO was originally introduced as a
theoretical foundation for extensions of logic programming languages, it can
also be viewed as a very general language to specify a wide range of
infinite-state concurrent systems.
Our approach is based on the relation between backward reachability and
provability highlighted in our previous work on propositional LO programs.
Following this line of research, we define here a general framework for the
bottom-up evaluation of first order linear logic specifications. The evaluation
procedure is based on an effective fixpoint operator working on a symbolic
representation of infinite collections of first order linear logic formulas.
The theory of well quasi-orderings can be used to provide sufficient conditions
for the termination of the evaluation of non trivial fragments of first order
linear logic.Comment: 53 pages, 12 figures "Under consideration for publication in Theory
and Practice of Logic Programming
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