Laure Petrucci

The Petri net markup language: concepts, technology, and tools

The Petri Net Markup Language (PNML) is an XML-based interchange format for Petri nets. In order to support different versions of Petri nets and, in particular, future versions of Petri nets, PNML allows the definition of Petri net types. Due to this flexibility, PNML is a starting point for a standard interchange format for Petri nets. This paper discusses the design principles, the basic concepts, and the underlying XML technology of PNML. The main purpose of this paper is to disseminate the ideas of PNML and to stimulate discussion on and contributions to a standard Petri net interchange format.

Modular Analysis of Petri Nets

This paper shows how two of the most important analysis methods for Petri nets can be performed in a modular way. We illustrate our techniques by means of modular Place/Transitions nets (modular PT-nets) in which the individual modules interact via shared places and shared transitions. For place invariants we show that it is possible to construct invariants of the total modular PT-net from invariants of the individual modules. For state spaces, we show that it is possible to decide behavioural properties of the modular PT-net from state spaces of the individual modules plus a synchronization graph, without unfolding to the ordinary state space. The generalization of our techniques to high-level Petri nets is rather straightforward.

FAST: Fast Acceleration of Symbolic Transition Systems

fast is a tool for the analysis of infinite systems. This paper describes the underlying theory, the architecture choices that have been made in the tool design. The user must provide a model to analyse, the property to check and a computation policy. Several such policies are proposed as a standard in the package, others can be added by the user. fast capabilities are compared with those of other tools. A range of case studies from the literature has been investigated.

FAST: acceleration from theory to practice

Fast acceleration of symbolic transition systems (Fast) is a tool for the analysis of systems manipulating unbounded integer variables. We check safety properties by computing the reachability set of the system under study. Even if this reachability set is not necessarily recursive, we use innovative techniques, namely symbolic representation, acceleration and circuit selection, to increase convergence. Fast has proved to perform very well on case studies. This paper describes the tool, from the underlying theory to the architecture choices. Finally, Fast capabilities are compared with those of other tools. A range of case studies from the literature is investigated.

Improved multi-core nested depth-first search

This paper presents Cndfs, a tight integration of two earlier multi-core nested depth-first search (Ndfs) algorithms for LTL model checking. Cndfs combines the different strengths and avoids some weaknesses of its predecessors. We compare Cndfs to an earlier ad-hoc combination of those two algorithms and show several benefits: It has shorter and simpler code and a simpler correctness proof. It exhibits more robust performance with similar scalability, while at the same time reducing memory requirements. The algorithm has been implemented in the multi-core backend of the LTSmin model checker, which is now benchmarked for the first time on a 48 core machine (previously 16). The experiments demonstrate better scalability than other parallel LTL model checking algorithms, but we also investigate apparent bottlenecks. Finally, we noticed that the multi-core Ndfs algorithms produce shorter counterexamples, surprisingly often shorter than their BFS-based counterparts.

Modular State Space Analysis of Coloured Petri Nets

State Space Analysis is one of the most developed analysis methods for Petri Nets. The main problem of state space analysis is the size of the state spaces. Several ways to reduce it have been proposed but cannot yet handle industrial size systems.

An Approach to Distributed State Space Exploration for Coloured Petri Nets

We present an approach and associated computer tool support for conducting distributed state space exploration for Coloured Petri Nets (CPNs). The distributed state space exploration is based on the introduction of a coordinating process and a number of worker processes. The worker processes are responsible for the storage of states and the computation of successor states. The coordinator process is responsible for the distribution of states and termination detection. A main virtue of our approach is that it can be directly implemented in the existing single-threaded framework of Design/CPN and CPN Tools. This makes the distributed state space exploration and analysis largely transparent to the analyst. We illustrate the use of the developed tool on an example.

Towards a Modular Analysis of Coloured Petri Nets

The use of different High-level Petri net formalisms has made it possible to create Petri net models of large systems. Even though the use of such models allows the modeller to create compact representations of data and action, the size of models has been increasing. A large model can make it difficult to handle the complexity of the modelling as well as the analysis of the total model. It is well-known that the use of a modular approach to modelling has a lot of advantages. A modular approach allows the modeller to consider different parts of the system independently of one another and also to reuse the same module in different systems. A modular approach to analysis is also attractive. It often dramatically decreases the complexity of the analysis task.

PNML framework: an extendable reference implementation of the petri net markup language

The International Standard on Petri nets, ISO/IEC 15909, provides a formal semantics and syntax to enable model interchange and industrial dissemination. Part 2 defines a concrete interchange format as an XML-based language: PNML. This language is bound to evolve together with future developments of the standard. This paper presents PNML Framework, a companion implementation of the standard. It provides developers of Petri net tools with a convenient and fast way to implement support of PNML documents. It abstracts away from any XML explicit manipulation and ensures compliance with the standard by using APIs.

Parallel nested depth-first searches for LTL model checking

Even though the well-known nested-depth first search algorithm for LTL model checking provides good performance, it cannot benefit from the recent advent of multi-core computers. This paper proposes a new version of this algorithm, adapted to multi-core architectures with a shared memory. It can exhibit good speed-ups as supported by a series of experiments.