1 Coloured Petri Nets and Education Søren Christensen Department of Computer Science University of Aarhus Denmark 4th Advanced Course on Petri Nets 2003, Eichstätt, Germany

2 This presentation aims to give you zSuggestions for general questions when preparing courses zSuggestions for subjects zExamples of different kinds of courses related to Coloured Petri Nets zPointer to examples of material, i.e., slides, examples, tools,... zCourage to “try it when you get home”!

3 General Questions to guide the planning of the course zWho is the Audience? y1st year Students, Software Engineers,... zWhy should they learn about Coloured Petri Nets? yA tool to solve problems yAn example of an interesting formalism zWhat is the most important focus? yGeneral understanding yConcrete methods and tools for a specific problem

4 General Questions to guide the planning of the course (2) zHow should the subject be presented? yLevel of Detail yExercise / Lectures yHistorical / Thematic yBottom Up / Top Down zPractical limitations yAvailable time, tools, and other resources

5 Coloured Petri Nets, a wide area, you need to focus…

6 High-level Petri Nets, Special Concerns zNet Structure yTop Down zInscription Language yBottom Up zHow to find the “right” level of abstraction yExamples of models from the same application areas

7 Examples of course activities zColoured Petri Nets as a tool in teaching Distributed Systems and Network protocols zColoured Petri Nets as a tool in teaching Process Modelling zSystems Design for Software Engineers zColoured Petri Nets: Two Part Course yIntroduction and Workshop Participation yEither State Space Methods or modeling project zProjects: Theory, Tools and Applications

8 Coloured Petri Nets as a tool in teaching Distributed Systems and Network protocols z2. or 3. year Computer Science students y students yHas been given in a number of variations during the last 10 years zThe aim is to give the students a tool to understand and discuss protocols and algorithms in distributed systems zInformal introduction y6 hours of lecture + tool demo + reading + exercises yJensen: Vol. 1 (pages 1-55 and ) zExamples yStandard Networking book, but many examples translated to CP-nets zWork with tools ySmall exercises, partial nets yLarger mandatory exercise zhttp:// (In Danish)

9 Coloured Petri Nets as a tool in teaching Process Modelling z1. year “Technology Management” Students zAround 200 students zVery comprehensive notes yBasic Concepts of Classical Petri Nets yApplication of Classical Petri Nets yExtending Classical Petri Nets by Adding Color and Time: A Gentle Introduction yColoured Petri Nets: The Language yHierarchical Petri Nets zhttp://tmitwww.tm.tue.nl/staff/wvdaalst/courses/pm/pm.htmlhttp://tmitwww.tm.tue.nl/staff/wvdaalst/courses/pm/pm.html

10 Systems Design for Software Engineers zSoftware Engineers y2-6 Software Engineers yIntense short course, days zSpecially tailored for a company yIntroduction + tool demo using prepared example that the Software Engineers know from their ordinary work y“The Practitioner's Guide to Coloured Petri Nets” zWork with tools ySmall exercises, partial nets yMore models of the same system

11 Coloured Petri Nets: Two Part Course z4. year Computer Science Students zPart 1: Introduction and Workshop Participation yIntroduction to the areas needed to read and understand the papers accepted for the CPN workshop yGroups of students read, review and present papers yParticipate in the CPN workshop zPart 2: Either State Space Methods or Modeling project

12 Projects: Theory, Tools and Applications zShort Student projects yMany smaller projects typically related to the course zMaster Thesis projects zPhD projects

13 Subjects for Master Thesis zModular State Spaces in Design/CPN zRouting in mobile ad-hoc networks zAnalysis of GSM Handovers using Coloured Petri Nets zI/O Efficient State-Space Storage zDistributed Methods for Computation and Analysis of a Coloured Petri Net State Space zModelling of interactive, event based multimedia systems using Coloured Petri Nets zOn-the-fly LTL Model Checking in Design/CPN zInternal Network Security - Defending the Network from the Inside zAutomatic Code Generation from Coloured Petri Nets zColoured Petri Nets and State Space Reduction Methods zDesign and Analysis of a Bus Scheduling System by Means of Coloured Petri Nets zInterval Timed Coloured Petri Nets

14 PhD thesis subjects zColoured Petri Nets - a Pragmatic Formal Method for Designing and Analysing Distributed Systems zState Space Methods for Coloured Petri Nets zPerformance Analysis using Coloured Petri Nets zFacilitating the Practical Use of Coloured Petri Nets zThe Symmetry Method for Coloured Petri Nets - Theory, Tools, and Practical Use zSweeping the State Space - A Sweep-Line State Space Exploration Method

15 Repository of Presentations zGeneral zApplications zState Spaces zPlace Invariants zTools zhttp://

16 Introductory Papers that we often use zL.M. Kristensen, S. Christensen, K. Jensen: The Practitioner's Guide to Coloured Petri Nets. International Journal on Software Tools for Technology Transfer, 2 (1998), Springer Verlag, yKeywords: Introduction to CP-nets, Simulation, State spaces, Occurrence graphs, CP-nets with time, Hierarchical CP-nets, Tool support, Application, General. yComments: This paper provides a comprehensive road map to the practical use of CP-nets and the Design/CPN tool. The paper is self- contained and does not assume any prior knowledge of Petri nets and CP-nets nor any experience with the Design/CPN tool. zK. Jensen: A Brief Introduction to Coloured Petri Nets. In: E. Brinksma (ed.): Tools and Algorithms for the Construction and Analysis of Systems. Proceeding of the TACAS'97 Workshop, Enschede, The Netherlands 1997, Lecture Notes in Computer Science Vol. 1217, Springer-Verlag 1997, yKeywords: Introduction to CP-nets, General. yComments: A very brief introduction to CP-nets and their analysis methods. zK. Jensen: An Introduction to the Practical Use of Coloured Petri Nets. In: W. Reisig and G. Rozenberg (eds.): Lectures on Petri Nets II: Applications, Lecture Notes in Computer Science vol. 1492, Springer-Verlag 1998, yKeywords: Introduction to CP-nets, Simulation, State spaces, Condensed state spaces, Occurrence graphs, CP-nets with time, Hierarchical CP-nets, Tool support, Application, General. yComments: A good introduction to the practical use of CP-nets and the CPN tools. zK. Jensen: An Introduction to the Theoretical Aspects of Coloured Petri Nets. In: J.W. de Bakker, W.-P. de Roever, G. Rozenberg (eds.): A Decade of Concurrency, Lecture Notes in Computer Science vol. 803, Springer-Verlag 1994, yKeywords: Introduction to CP-nets, Formal definition, Dynamic properties, State spaces, Occurrence graphs, Place invariants, General. yComments: A good introduction to the theoretical aspects of CP-nets. zhttp://

17 Coloured Petri Nets - Modelling and Analysis “To cope with the complexity of modern computing systems, it becomes more and more crucial to be able to debug and test the central parts of system designs before implementation starts. One way to do this is to build a prototype. Another and faster way is to build a model. This allows the designer to inspect the model and in this way learn about the behaviour of the system. This is similar to an architect who builds a scaled model of a new building to inspect and discuss its properties before the construction starts. Coloured Petri Nets is a modelling language that allows the user to build models that can be executed by a computer. In this way it is possible to make simulations which illustrates the behaviour of the system in selected scenarios. Having constructed a CPN model, it is also possible to apply a number of mathematical analysis methods to prove that the system design possesses certain properties, e.g. absence of deadlock and functional correctness. Finally, the CPN model can be used to predict and improve the efficiency of the system, e.g., the speed at which it operates. Coloured Petri Nets are used to model systems in which communication, synchronisation and resource sharing are crucial, e.g. communication protocols and other software for distributed systems. The course introduces the theory and practice behind Coloured Petri Nets, its analysis methods, and tool support. The students are expected to build a number of small models and investigate these by means of simulation and formal analysis methods. Although the examples will be small, they will be large enough to illustrate the main ideas and problems. Hence, they are a good foundation for students who later need to build models in their future job as system designers.”