Overview (in progress)

Workshops

Workshop on Algorithms & Theories for the Analysis of Event Data (ATAED'2015)

The workshop aims to attract papers related to Process Mining, Region Theory and other synthesis techniques. These techniques have in common that "lower level" behavioral descriptions (event logs, partial orders, transition systems, etc.) are used to create "higher level" process models (e.g., various classes of Petri nets).

International Workshop on Petri Nets and Software Engineering (PNSE'2015)

For the successful realisation of complex systems of interacting and reactive software and hardware components the use of a precise language at different stages of the development process is of crucial importance. Petri nets are becoming increasingly popular in this area, as they provide a uniform language supporting the tasks of modelling, validation, and verification. Their popularity is due to the fact that Petri nets capture fundamental aspects of causality, concurrency and choice in a natural and mathematically precise way without compromising readability.

The use of Petri Nets (P/T-Nets, Coloured Petri Nets and extensions) in the formal process of software engineering, covering modelling, validation, and verification, will be presented as well as their application and tools supporting the disciplines mentioned above.

6th International Workshop on Biological Processes and Petri Nets (BioPPN'2015)

The goal of this workshop is to provide a platform for researchers aiming at fundamental research and real life applications of Petri nets and other concurrency models in Systems and Synthetic Biology. Systems and Synthetic Biology are full of challenges and open issues, with adequate modelling and analysis techniques being one of them, specifically when multiple scales and multiple levels come into play. We are looking for approaches helping to bridge the gap between different formalisms, with Petri nets being one them, as they offer a family of related models, which can be used as a kind of umbrella formalism - models may share the network structure, but vary in their kinetic details (quantitative information).

International Workshop on Petri nets for Adaptive Discrete-Event Control Systems (ADECS'2015)

The new generation of Discrete-Event Control Systems (DECS) is addressing new important criteria as flexibility and agility. To reduce the development cost, these systems should be changed and adapted to their environment without any disturbance. Several academic and industrial research works have been made in recent years to develop reconfigurable adaptive systems. We distinguish in these works two reconfiguration policies: static and dynamic reconfigurations such that static reconfigurations are applied off-line to apply changes before any system cold start, whereas dynamic reconfigurations are dynamically applied at run-time. Two cases exist in the second policy: manual reconfigurations applied by users and automatic reconfigurations applied by intelligent agents. This workshop intends to gather students and researchers who have interests in the application of concurrency modelling and analysis techniques for adaptive DECS. Case studies with specific focus on reconfigurability and demonstrating the specific power of different Petri net classes are especially encouraged.

Petri Net course

The Petri Net Course takes place from Sunday to Tuesday before the conference. It offers a thorough introduction to Petri Nets in four half-day modules on Sunday and Monday:

On Tuesday there is a choice between two full-day tutorial modules on applications of Petri Nets and/or new developments presented by experts in the area. This year the subjects are:

Each module of the course can be taken separately. In particular, the lectures on Tuesday can be followed as independent Tutorials.

Credits

All Course modules are open for everyone interested. For the Course as a whole, graduate and PhD Students are the intended audience. It is possible to earn credit points (3 ECTS awarded by Leiden University, NL) on basis of successful participation in the Course including: a preparation phase before the Course; examinations for the theory modules in the form of small exercises or homework; and a written report as an outcome of a project associated with the tutorial chosen for the third day.

For the preparation phase, students who have registered for the full Course, will receive one to two weeks in advance material containing preliminaries on the philosophy of net theory, basic notions, small examples, typical application areas etc. For the examination of the Sunday/Monday modules, time will be available during the Course. The completion of the assignment of the Tuesday module will take place after the Course as agreed with the lecturer(s).

Module 1: Basic net classes

Content: This is the introductory module to the Petri Net Course and as such provides key concepts and definitions underlying almost every Petri net model. Guided by a motivating example, principles of net theory are discussed highlighting local dynamics and concurrency. Two basic net classes are introduced and investigated: Place/Transition Systems and Elementary Net (EN) Systems. We consider the occurrence rule (token game), reachability, state graph, behavioural properties like deadlock and boundedness, behavioural equivalence and normal forms. The fundamental situations causality, conflict, concurrency, and confusion are explained in the context of EN Systems. We discuss EN system behaviour in terms of sequential and non-sequential observations. Finally, basic analysis techniques are presented to establish structural properties of nets.

  • Date: Sunday, June, 21st.
  • Location: Forum Building, room OF2070.
  • Time: 9:00 ‐ 10:30 and 11:00 ‐ 12:30
  • Lecturer: Jörg Dessel

Module 2: Coloured Petri Nets 1 - Modelling and CPN Tools

This module focusses on the constructs and definition of the Coloured Petri Nets (CPNs) modelling language. CPNs belong to the class of high-level Petri nets and combines Petri Nets with the functional programming language Standard ML (SML). Petri nets provides the primitives for modelling concurrency, communication, and synchronisation while SML provides the primitives for modelling data manipulation and for creating compact and parameterised models. CPNs and the supporting computer tool CPN Tools have been widely used in practice for modelling and validating a wide range of concurrent and distributed systems. Having completed this module the participants should be able to:

  • explain and use the basic constructs of the CPN modelling language
  • explain the syntax and semantics of CPNs
  • structure CPN models into a hierarchically related set of modules
  • apply CPN Tools for construction and simulation of CPN models
The module includes hands-on experiments with CPN Tools.

Module 3: Coloured Petri Nets 2 - Verification and Applications

Explicit state space exploration is one of the main approaches to computer-aided verification of concurrent systems, and it is one of the main analysis methods for Coloured Petri Nets (CPNs). This module provides an introduction to state space methods in the context of CPNs, and explains how standard behavioural properties of CPNs can be verified fully automatically using state spaces and the support for state space exploration provided by CPN Tools. The module also introduces the basics of temporal logic and associated model checking algorithms for verifying more general behavioral properties of concurrent systems. Examples demonstrating the practical use of CPN modelling and verification on industrial-sized systems will be presented. Having completed this module the participants should be able to:

  • define standard behavioural properties of CPNs and express behavioral properties in temporal logic
  • explain the basic concepts of state spaces and how they are computed
  • explain how behavioural properties can be automatically checked from state spaces
  • apply state spaces and model checking techniques for verification of CPN models
The module includes hands-on experiments with CPN Tools.

Module 4: Time(d) and Stochastic Petri Nets

This module presents different ways to introduce time in Petri nets. The focus will be on two kinds of models: (1) either a time is non deterministically chosen, or (2) it is chosen based on a probability distribution. The two main models associated with non deterministic choices are time Petri nets (TPN) where time is associated with a delay for transition firings and timed Petri nets (TdPN) where time is associated with the age of tokens. We introduce the syntax and semantics of both models and we develop some standard analysis techniques. In generalized stochastic Petri nets (GSPN) the delay for transition firings is obtained by sampling a random variable. For particular kinds of distributions, we describe the construction of a continuous time Markov chain on which the main performance indices can be computed. The module will include a short description of Markov chains in order to be self-contained.

  • Date: Monday, June, 22nd.
  • Location: Forum Building, auditorium G.
  • Time: 14:00 ‐ 15:30 and 16:00 ‐ 17:30
  • Lecturer: Serge Haddad

Tutorial: From Symmetric Nets to Symmetric Nets with Bags

Abstract: Depending on the system to model and analyse, using place/transition nets may easily be cumbersome and error-prone. Hence, it might be convenient to use some class of high-level nets. Coloured Petri nets enjoy the use of a high-level language to describe data while the net structure captures the flow of information. Although they provide very nice means for modelling, their generality has the drawback of the difficulty to apply efficient analysis techniques.

In this tutorial, we focus on symmetric nets which are high-level nets with a limited set of allowed data types, allowing for efficient state space analysis. We also tackle their extension to symmetric nets with bags for which analysis can still be applied.

The tutorial will present the underlying theory, the verification approaches, typical applications, and will put these into practice through hands-on sessions using the CosyVerif verification environment.

Tutorial: Modeling, Synthesis and Verification of Hardware

Abstract: In this tutorial we will present an up-to-date vision of and approach to applying Petri nets and related concurrency models to modelling, verification and synthesis of electronic circuits. Petri nets are seen here as a unifying modelling language for reasoning about the behaviour of digital circuits and systems, where various application-specific and engineering-specific modelling notations can be used as front-end notations. In the first half of the tutorial we will introduce theoretical aspects of our methodology, while the second half will be devoted to the familiarisation with the toolkit Workcraft, which supports (and is constantly in the process of expansion!) a range of front-end notations for digital hardware, captured at different levels of abstraction and granularity. The examples of the front end notation we will be presenting include both structurally oriented models, such as data-flow structures and logic circuit net-lists, as well a behavioural formalisms, such as state-graphs and conditional partial order graphs.

While the spectrum of hardware that can be modelled and designed includes both synchronous (aka globally clocked) and asynchronous (aka self-timed) circuits, our main focus is on the support for designing asynchronous logic. Why? The reason for that is that self-timed circuits are inherently concurrent and the role played by Petri nets for them is as fundamental as the role played by finite-state machines in traditional synchronous design. Thus, the hardware whose behavioural semantics is conveniently underpinned by Petri nets includes digital processors, pipelines, arbiters, interfaces and controllers, and most notably digital control for analog electronics, such as power converters.

Model-Checking Contest

The Model Checking Contest is a yearly event, jointly held with the Petri Nets conference, that gathers developers of formal verification tools for concurrent systems.

The first goal of the Model Checking Contest is to enable the assessment of existing tools on a set of models (i.e., benchmarks) proposed by the scientific community. All tools are compared on the same benchmarks and using the same computing platform, so that a fair comparison can be made, which is not possible using traditional scientific publications, which use different benchmarks executed on different platforms.

The second goal of the Model Checking Contest is to infer conclusions about the respective efficiency of verification techniques for Petri nets (decision diagrams, partial orders, symmetries, etc.) depending to the particular characteristics of models under analysis. Through the feedback on tools efficiency, we aim at identifying which techniques can best tackle a given class of models. Finally, the Model Checking Contest seeks to be a friendly place where developers meet, exchange, and collaborate to enhance their verification tools.

Tool presentation session

During the conference reception (on Wednesday evening), a tool presentation session will be organised. All participants are welcome to present their tool. A poster is welcome too.

If you want to present your favourite tool during the session, send an e-mail to the organisers (pn2015 [at] lit.ulb.ac.be).

Tool presentation(s) that are already announced:

  • Jonny Beaumont: A Workcraft plugin for the Algebra of Parameterised Graphs
  • Alessandro De Gennaro: SCENCO
  • Fabrice Kordon: Generating Test Scenarios With CosyVerif in MIDAS
  • Franck Pommereau: SNAKES
  • Sebastiaan J. van Zelst: Data Streams in ProM 6: A Single-node Architecture
  • Karsten Wolf: LoLA 2.0.