Modeling Workflow within Distributed Systems

Yuhong Yan Flydragon Computer consulting,NY,USA

Alex Bejan ANCA Tech. RI,USAComputer Supported Cooperative Work in Design, The Sixt

h International Conference on, 2001

Outline Introduction Workflow Modeling Based on Petri Nets:

State of Art The Definition of Standard Workflow

Network Workflow Network Decomposition Conclusion

Introduction The main purpose of a WFMS is the support

of the definition, execution, registration and control of processes

Modeling business process is the start point of the workflow management techniques

The fact is that many WFMS’s modeling tools are paid less effort than the workflow engine

Introduction (cont.) Modeling tools drawbacks

No mathematical skills are used to analyze the properties of the processes

The current methods are not suitable in large scaled analysis

Consider the Petri Net as the modeling tools in this paper

We present the concept of Standard Workflow Structure and a set of standard workflow blocks

Also present the method of decomposing a large scaled workflow network into sub-networks

Workflow Modeling Based on Petri Nets: State of Art

Workflow Modeling Based on Petri Nets: State of Art

Workflow Modeling Based on Petri Nets: State of Art

The definition of Standard Workflow Networks Observe of the illness structures of a

workflow In Figure1 following the source place are 2

Or-branches. No matter what branch is executed, the token is blocked in p2 or p5 because transition a3 can never be triggered

The definition of Standard Workflow Networks

The definition of Standard Workflow Networks

The definition of Standard Workflow Networks

The definition of Standard Workflow Networks

The definition of Standard Workflow Networks

The definition of Standard Workflow Networks

A SWF-net has the following properties A SWF-net is bounded A SWF-net is live A SWF-net is sound

Workflow Network Decomposition Figure 3 is the whole Petri Net model To decompose a network:

How to divide the whole network How to build the synchronous relation

between sub-networks The properties of the sub-networks

Workflow Network Decomposition How to divide the network

Have to add new start and end places Adding start and end places under the

different sub-network situations How to synchronize different sub-

networks From figure, we can see the CA controls the

start of the SA at a1, while SA controls which branch of the 2 Or-connected branches in CA.

Workflow Network Decomposition

Workflow Network Decomposition

Workflow Network Decomposition

This paper presents a set of methods for modeling large-scaled workflow network

The soundness of single workflow net and the joint workflow net can be guaranteed

Not suitable in analyzing the undetermined relationships

Self-loop connection might be only one control relation between sub networks

Conclusion