Desel, Jörg

Freytag, Thomas

Oberweis, Andreas

Zimmer, Torsten

KITopen

VIPtoolA partial order based simulation tool for high-level Petri netsJörg Desel, Thomas Freytag, Institut AIFB, University of Karlsruhe, GermanyAndreas Oberweis, Torsten Zimmer, Institut für Wirtschaftsinformatik, University of Frankfurt, Germanydesel j freytag @aifb.uni-karlsruhe.deoberweis j zimmer @wiwi.uni-frankfurt.deShort descriptionVIPtool is a tool for editing, simulation and validation of high-level Petri nets. It implementsconcepts that are in the focus of a project named VIP (Verication of Information systems byevaluating partially-ordered runs of Petri nets). This project is a cooperative work of researchersat the universities of Frankfurt and Karlsruhe and is sponsored by the German Research Society(DFG). The main concern of this project is to establish a simulation and validation concept forPetri nets that is not based on the generation and evaluation of totally ordered sequences oftransitions but on partially ordered execution runs (process nets).Theoretical backgroundThere are two general views at the dynamic behaviour of a net model: The rst one - calledthe sequential semantics - looks at the set of ring sequences of a net. The second one - calledthe causal semantics - looks at the set of partially ordered runs (or processes) of a net. Whereasthe causal semantics is favorized in Petri net theory because of its ability to handle concurrency,the area of applications still is dominated by the sequential semantics because of their easy andstraight-away denition.There are also two ways to check (desired or undesired) properties of a net model: The rst one isto apply analysis methods from net theory deciding a property essentially by analysis of the statespace. This very clean way becomes inapplicable when systems are large and their state spacesuers from the state explosion. The second approach is not to consider all possible executions ofa net but only a well-chosen subset determined by simulation. The given property is then checkedagainst 'empirical' data - comparable to the systematic testing of a program.The VIP project tries to nd a way betwee these approaches, preserving the advantages andavoiding the disadvantages of each: simulate systems modelled by high-level Petri nets by generating partial ordered runs, check given system properties by evaluating these runs, specify these properties in a user-oriented graphical way and visualize dynamic system behaviour by means of its causal semantics optimize system performance through investigation of causal behaviourImplementationVIPtool is mainly written in Python, a freely available, object-oriented and interpreted scriptlanguage. Runtime-critical algorithmic parts (such as the simulator and the vericator) are writtenin ANSI-C and are compiled and linked directly into the interpreter as dynamic link libraries. Thegraphical user interface is based on an built-in extension of Python that gives full access to theTcl/Tk functionality.1Hardware requirementsVIPtool is available for Intel-PCs running Linux and Sun workstations running SunOS. A portto Windows 95/Windows NT is planned for the future.Software requirementsVIPtool requires Python version 1.4, Tcl version 7.5, Tk version 4.1 and an ANSI-compatible Ccompiler for building the sources.Structure and functionalityVIPtool consists of six main components: A net editor where nets can be edited and system properties can be graphically specied A process database containing all simulated processes A query component which accesses the process database and controls the property-based partof the simulation policy A vericator that does the 'pattern matching' in order to validate the given property againstthe contents of the process database A simulator which generates processes of the net according to a dynamic control mechanismwhich includes global termination rules, conict resolution rules, ring probabilities and rulesthat inuence the simulation policy depending on the specied property A process browser that visualizes process nets and gives additional information about thevalidation of the propertySimulatorFile  Edit  Sim  Options        Help<x><y><x,y>EditorFile  Edit  View  Options      HelpBrowserdesigns,editsasks Query-componentProcesssupportsvisualizesValidatorProcess databaseUserstartscontrolsstartsanswersevaluatesgeneratesinteractsContactFor further information about VIPtool please contactThomas Freytag, Institut AIFB, Universität Karlsruhe, D-76128 Karlsruhee-mail freytag@aifb.uni-karlsruhe.de - phone ++49-721-608-4063 - fax ++49-721-693717.2

VIPtool: a partial order based simulation tool for high-level Petri nets [online]

https://publikationen.bibliothek.kit.edu/3298/3128

VIPtool: a partial order based simulation tool for high-level Petri nets [online]

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