WoPeD Workflow Petri Net Designer

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1 WoPeD Workflow Petri Net Designer Thomas Freytag University of Cooperative Education (Berufsakademie) Department of Computer Science D Karlsruhe Abstract. WoPeD (WoPeD Petrinet Designer) is a Java-based software tool being developed as an open-source project at the University of Cooperative Education (BA) Karlsruhe, Germany. WoPeD uses the Petri Net Markup Language (PNML) as interchange format and is able to edit, simulate and analyse workflow Petri nets (WF-nets) as originally introduced by Wil van der Aalst. Keywords. Workflow nets, Java, PNML. 1 Quick Overwiew Name WoPeD Homepage Availability Free (open-source) Platforms Independendent (Java) Installer for Windows, Linux and MacOS Net class Workflow Nets, Place/Transition Nets File format PNML Features Graphical editor, simulator, analysing interface 2 Short description WoPeD is a simple, easy-to-use, platform-independent software tool for editing, analysing and visualizing workflow Petri nets. WoPeD is a successor work of the original software product named PWFtool which has already been presented and published in [FrL03]. WoPeD is freely available via the project website [WoP05] and runs on all operating systems for which a Java VM is available, in particular on all Windows 32-bit systems, most Linux distributions and MacOS X. WoPeD is mainly a tool for educational and publishing purposes. It aims to support lecturers, researchers and students in the field of Petri nets and Workflow Management in their daily work. By relating strictly to the original van der Aalst workflow net notation [Aal98], WoPeD is a handy tool to create lecture notes, interactive teaching material or example case studies. WoPeD can visualize the structure and the dynamics of workflow nets and can provide a deeper understanding of the underlying concepts. WoPeD has even successfully served as a software front-end for small student assessment projects. WoPeD offers a comfortable, intuitive modelling interface, a graphical interactive token game simulator and supports several export interfaces, including JPEG graphics, standard PNML [WeK03] and TPN. By this, net models created with WoPeD can easily be exported and furtherly investigated by third-party tools like Woflan [Wof05] or Pipe [Pip05].

2 3 Functional features The development of WoPeD started in Mai 2003 as a part of a diploma thesis [Lan03] at the University of Cooperative Education (BA) Karlsruhe. In the meantime, a growing and very productive project group has been established, consisting of staff persons and students of the BA Karlsruhe, but also of former students, neighbour universities and software engineers from local industry partners. The first public beta was published in March 2005 via Sourceforge, a well-established development platform for open-source projects. The current version of WoPeD is mainly implementing an elaborate graphical modelling environment and supplies the following functional features: Full graphical editor WoPeD provides a powerful graphical editor for place/transition nets. A multiple-document interface allows to work concurrently with several open nets. Smart editing functions Many comfortable editing features, e. g. cut, paste and copy functions (also across editor windows) as well as undo and redo functions (with unlimited history) and group and ungroup functions to simplify changes. Editor windows can be scaling arbitrarily, allowing to produce high-quality net graphics. A very useful feature is "smart-naming" allowing on-the-fly net element name editing and "smart-arc-drawing", allowing to create nets with a minimum of mouse clicks. Support for Workflow Nets WoPeD can handle tradional place/transition nets, but also supports the extended "van der Aalst"-like workflow net syntax with special split and join transitions (AND, XOR) and four trigger types (resource, time, message). Animated token game simulation The current net can be executed by playing the token game interactively. PNML-compliant file format The standard file format of WoPeD is based on the widely-accepted PNML syntax, enabling to export or import net models to and from other Petri net tools which are using PNML. The workflow net extensions are transparently translated into plain PNML Export to multiple formats WoPeD supports several output formats to use the created models either graphically (JPEG) or textually (TPN) to perform soundness checks with Woflan. Additionally, a direct call interface to Woflan is provided. Fully-integrated user manual An interactive HTML user manual is included an can be used from inside WoPeD.

3 4 Screenshots The following screenshots provide a visual impression of the user interface of WoPeD and are all based on version (first public beta release from Mar 25 th, 2005). Graphical editor Context menu for net elements

4 Woflan calling interface Configuration dialog

5 Interactive token game Built-in user manual

6 5 Future plans WoPeD is a work-in-progress project and is planned to be extended significantly in the near future. Subprocesses It will be possible to split workflow nets into light-weight, handy subprocesses, being able to handle even large process models. This feature should also allow the embedding of one subprocess definition in more than one workflow processes, leading to a collection of reusable process modules. Workflow patterns Another challenge will be the support of workflow patterns as discussed in recent publications and most promisingly implemented in the YAWL project [Yaw05]. By supporting the underlying pattern concept and interfacing to the YAWL syntax, WoPeD could serve as an alternative front-end for editing and validating engine-executable workflow processes. Qualititive analysis Moreover, WoPeD will be extended to by an analysis engine, being able to perform soundness checks by using built-in algorithms or by calling additional third-party tools. One important issue will be the future perspective of PNML and the (hopefully) increasing number of specialized analysis tools being able to understand this format. WoPeD could be again a graphical front-end for visualizing analysis results. Quantitative analysis Another important future extension of WoPeD is to allow the creation of a separate resource model in addition to the workflow process definition. By assigning resource classes (i. e. groups and roles) to workflow tasks and by specifying (estimated) execution times of each task as well as assigning (estimated) branching probabilities of OR-split transitions, it will be possible to apply performance measurement methods like those described by van der Aalst and van Hee in [AaH02]. Implementing the associated algorithm, WoPeD again can act as a problem solver and visualizing front-end for quantiative analysis results. 6 Conclusion WoPeD is a evolving tool for many purposes. Though currently mainly useful for teaching and presentation purposes, it is on its best way to become a powerful modelling and analysis platform for many workflow-related applications.

7 7 References [AaH02] W. M. P. van der Aalst, K. van Hee. Workflow Management Models, Methods and Systems. MIT Press, Cambridge, [Aal98] W. M. P. van der Aalst. The Application of Petri Nets to Workflow Management. The Journal of Circuits, Systems and Computers, 8 (1) 1998, pp [Fre01] T. Freytag. Softwarevalidierung durch Auswertung von Petrinetz-Abläufen. PhD thesis, University of Karlsruhe, [FrL03] T. Freytag, S. I. Landes. PWFtool a Petri net workflow modelling environment. Proceedings of the Workshop "Algorithmen und Werkzeuge für Petrinetze (AWPN), Eichstätt, [Lan03] S. I. Landes. Entwicklung eines Modellierungstools für Workflow-Petrinetze. Diploma Thesis BA Karlsruhe, [Pip05] The PIPE project homepage [WeK03] M. Weber, E. Kindler. The Petri Net Markup Language. In: H. Ehrig, W. Reisig, G. Rozenberg, H. Weger (Eds.). Petri Net Technology for Communication Based Systems, LNCS 2472, Springer [Ver04] H. M. W. Verbeek. Verification of WF-nets. PhD thesis, TU Eindhoven, [Wof05] The Woflan project homepage [WoP05] The WoPeD project homepage [Yaw05] The YAWL project homepage