Synthesis of Bounded Choice-Free Petri Nets

This paper describes a synthesis algorithm tailored to the construction of choice-free Petri nets from finite persistent transition systems. With this goal in mind, a minimised set of simplified systems of linear inequalities is distilled from a general region-theoretic approach, leading to algorithmic improvements as well as to a partial characterisation of the class of persistent transition systems that have a choice-free Petri net realisation

Indefinite waitings in MIRELA systems

MIRELA is a high-level language and a rapid prototyping framework dedicated to systems where virtual and digital objects coexist in the same environment and interact in real time. Its semantics is given in the form of networks of timed automata, which can be checked using symbolic methods. This paper shows how to detect various kinds of indefinite waitings in the components of such systems. The method is experimented using the PRISM model checker.Comment: In Proceedings ESSS 2015, arXiv:1506.0325

Incremental and unifying modelling formalism for biological interaction networks

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A Decidable Characterization of a Graphical Pi-calculus with Iterators

This paper presents the Pi-graphs, a visual paradigm for the modelling and verification of mobile systems. The language is a graphical variant of the Pi-calculus with iterators to express non-terminating behaviors. The operational semantics of Pi-graphs use ground notions of labelled transition and bisimulation, which means standard verification techniques can be applied. We show that bisimilarity is decidable for the proposed semantics, a result obtained thanks to an original notion of causal clock as well as the automatic garbage collection of unused names.Comment: In Proceedings INFINITY 2010, arXiv:1010.611

On Deadlockability, Liveness and Reversibility in Subclasses of Weighted Petri Nets

International audienceLiveness, (non-)deadlockability and reversibility are behavioral properties of Petri nets that are fundamental for many real-world systems. Such properties are often required to be mono-tonic, meaning preserved upon any increase of the marking. However, their checking is intractable in general and their monotonicity is not always satisfied. To simplify the analysis of these features, structural approaches have been fruitfully exploited in particular subclasses of Petri nets, deriving the behavior from the underlying graph and the initial marking only, often in polynomial time. In this paper, we further develop these efficient structural methods to analyze deadlockability, live-ness, reversibility and their monotonicity in weighted Petri nets. We focus on the join-free subclass, which forbids synchronizations, and on the homogeneous asymmetric-choice subclass, which allows conflicts and synchronizations in a restricted fashion. For the join-free nets, we provide several structural conditions for checking liveness, (non-)deadlock-ability, reversibility and their monotonicity. Some of these methods operate in polynomial time. Furthermore , in this class, we show that liveness, non-deadlockability and reversibility, taken together or separately, are not always monotonic, even under the assumptions of structural boundedness and structural liveness. These facts delineate more sharply the frontier between monotonicity and non-monotonicity of the behavior in weighted Petri nets, present already in the join-free subclass. In addition, we use part of this new material to correct a flaw in the proof of a previous characterization of monotonic liveness and boundedness for homogeneous asymmetric-choice nets, published in 2004 and left unnoticed

Dynamic exploration of multi-agent systems with timed periodic tasks

We formalise and study multi-agent timed models MAPTs (Multi-Agent with timed Periodic Tasks), where each agent is associated to a regular timed schema upon which all possibles actions of the agent rely. MAPTs allow for an accelerated semantics and a layered structure of the state space, so that it is possible to explore the latter dynamically and use heuristics to greatly reduce the computation time needed to address reachability problems. We apply MAPTs to explore state spaces of autonomous vehicles and compare it with other approaches in terms of expressivity, abstraction level and computation time

Efficient reachability graph representation of Petri nets with unbounded counters

International audienceIn this paper, we define a class of Petri nets, called Petri nets with counters, that can be seen as place/transition Petri nets enriched with a vector of integer variables on which linear operations may be applied. Their semantics usually leads to huge or infinite reachability graphs. Then, a more compact representation for this semantics is defined as a symbolic state graph whose nodes possibly encode infinitely many values for the variables. Both representations are shown behaviourally equivalent

Deadlock and temporal properties analysis in mixed reality applications

International audienceMixed reality systems overlay real data with virtual information in order to assist users in their current task, they are used in many fields (surgery, maintenance, entertainment). Such systems generally combine several hardware components operating at different time scales, and software that has to cope with these timing constraints. MIRELA, for Mixed Reality Language, is a framework aimed at modelling, analysing and implementing systems composed of sensors, processing units, shared memories and rendering loops, communicating in a well-defined manner and submitted to timing constraints. The paper describes how harmful software behaviour, which may result in possible hardware deterioration or revert the system's primary goal from user assistance to user impediment, may be detected such as (global and local) deadlocks or starvation features. This also includes a study of temporal properties resulting in a finer understanding of the software timing behaviour, in order to fix it if needed