WF-Net Based Modeling and Soundness Verification of Interworkflows

Shingo YAMAGUCHI  Hajime MATSUO  Qi-Wei GE  Minoru TANAKA  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E90-A   No.4   pp.829-835
Publication Date: 2007/04/01
Online ISSN: 1745-1337
DOI: 10.1093/ietfec/e90-a.4.829
Print ISSN: 0916-8508
Type of Manuscript: Special Section PAPER (Special Section on Selected Papers from the 19th Workshop on Circuits and Systems in Karuizawa)
interworkflow,  interoperability,  workflow net,  Petri net,  soundness,  

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This paper deals with WF-net based modeling and verification of interorganizational workflows (interworkflows for short) based on the protocol of WfMC. In the protocol, there are three patterns of interoperability: Chained, Nested, and Parallel synchronized; and an interworkflow is constructed by using those interoperability patterns. We first give a WF-net based modeling method. In this modeling method, the three interoperability patterns are respectively expressed in terms of WF-nets. They enable us to model a given interworkflow as a WF-net by connecting WF-nets representing its constituent workflows. We also indicate that if free choice WF-nets are connected by means of any combination of the three patterns then the resultant WF-net is asymmetric choice. Next we discuss verification of WF-nets obtained through the modeling method. Intuitively, a WF-net is said to be sound if, for any case, the initial state is always transformed to the final state. Unfortunately, even if every constituent WF-net is sound FC, the resultant WF-net is not always sound. We give a sufficient condition of non-soundness checkable in polynomial time. We also show that if they are connected by only the Nested pattern then the resultant WF-net is sound.