مدل سازی فرآیندهای جریان کار با شبکه های پتری رنگی

The definition and maintenance of workflow processes have become important tasks for enterprises as workflow management systems (WFMS) are systematically applied to critical business processes. In order to simplify the management and usage of workflow processes and to integrate with other applications, a good modeling method is essential. The WFCP-net (workflow-net based on colored Petri net) is an extension of the workflow-net (WF-net) which can be used to model family of workflow processes with similar process routes and logic rules. An expanding suite of tools, which currently includes, can support its application: a process structure graph editor, a WF script (workflow script language for writing business rules) editor and translator (translate WF script into Java classes) and a dynamically loadable workflow engine.

These years have seen many workflow management systems implemented on a wide range of organizations. From office automation to enterprise application integration, workflow technology is playing a vital role. Workflow management systems are being used to model, execute, monitor, coordinate and improve business process of real or virtual organizations. A WFMS consists of two basic components: workflow models and workflow enactment engine. Various authors have stressed the need for formal foundations of process specifications techniques [1] and [8], and many researches focus on conceptual model of workflow [6], [7] and [18]. The Meteor project [12] developed workflow specification language (WSL), a declarative rule-based language, to expression application level interaction with multi-tasks and task specification language (TSL) to depict individual task issues. These languages were used to address the issues of inter-task dependencies, data formatting, data exchange, error handling and recovery. Ellis used information control net (ICN) to represent control flow and data flow [8]. But the ICN definition has only defined individual process model rather than family of models with similar rules and routes. Hofstede use Task Structure to specify workflow processes [9], van der Aalst and coworkers applied Petri net to workflow modeling in a series of papers such as [1], [2] and [3]. While the Petri net variant approach has a solid mathematical basis as well as analysis and verification algorithms and tools, there are still some outstanding issues to be addressed such as the description of family of workflow processes and convenient methods and tools to integrate WFMS with enterprise application software. In seriously competitive worldwide markets, it is vital for enterprises to increasingly improve their business process to meet the demand of consumers, especially for new product development departments. In Collaborative Product Commerce environments [16], there are higher requirements for workflow management process models and execution engines than in rigorous product workflow management system. The workflow management components must have powerful methods to control product design processes and engineering change processes; a case study presented in Section 2 exemplifies these requirements. The remainder of this paper is organized as follows. Section 2 introduces a case study of workflow processes and puts forward the requirements. Section 3 presents our workflow conceptual architecture. In Section 4, we define WFCP-net by extending WF-net with data type and show that this method is powerful enough to model process families by modeling the case study given in Section 2. Section 5 presents our implementation of workflow engine and other modeling tools.

This paper has used colored Petri net as a formal language for workflow process definition, and proposed WFCP-net to extend WF-net. With WFCP-net, supervisors of WFMS can define compact and comprehensive families of workflow process specifications in order to decrease the number of business processes for different types of cases with arc expressions, guard functions and multiple exits. The workflow script language and editor/translator allow users to write business rules and to integrate with the applications. All of these enhance the flexibility of workflow and make up of the core of simulation. For future work, we plan to work on editing ebXML business process models with these method and tools [13].