مدل سازی جریان کار برای فرآیندهای مجازی: رویکرد محافظت دستور مشاهده فرآیند

Conducting workflow management allows virtual enterprises to collaboratively manage business processes. Given the diverse requirements of the participants involved in a business process, providing various participants with adequate process information is critical to effective workflow management. This work describes a novel process-view, i.e., an abstracted process which is derived from a base process to provide process abstraction, for modeling a virtual workflow process. The proposed process-view model enhances the conventional activity-based process models by providing different participants with various views of a process. Moreover, this work presents a novel order-preserving approach to derive a process-view from a base process. The approach proposed herein can preserve the original ordering of activities in the base process. Additionally, a formal model is presented to define an order-preserving process-view. Finally, an algorithm is proposed for automatically generating an order-preserving process-view. The proposed approach increases the flexibility and functionality of workflow management systems.

Workflow management via workflow management systems (WfMSs) not only facilitates electronic commerce, but also allows virtual enterprises to collaboratively manage business processes. As an effective process management tool, WfMSs allow businesses to analyze, simulate, design, enact, control and monitor their overall business processes [1] and [2]. The support of a WfMS allows various participants to collaborate in effectively managing a workflow-controlled business processes. The participants represent particular positions in a company or particular companies in a supply chain. In practice, these participants possess different needs and levels of authority when obtaining information on business processes. To facilitate effective workflow management, a WfMS should provide various participants with adequate process information. For example, a high-level manager may require aggregated information on a process, while a marketing manager may not have the authority or need to know each specific step of the production flow. These requirements create the need for a flexible process model capable of providing appropriate processes abstraction for various roles within an enterprise. Furthermore, interorganizational coordination via WfMSs has become a critical success factor for businesses in rapidly fluctuating and complex business environments. Besides the interoperability issues of heterogeneous WfMSs, in a WfMS-supported supply chain (or called multi-enterprise process [3]), each participatory organization wants to conceal its own processes from other organizations, and different organizations require different supply chain information. In sum, providing aggregated information or encapsulating sensitive data requires the development of a workflow model capable of offering adequate abstracted processes for different levels, units, and organizations. Despite notational differences, activity-based methodologies are extensively used process modeling techniques, and have been extensively adopted for commercial products, research projects, and standards, e.g., MQSeries Workflow [4], Ultimus [5], METEOR [6], and workflow management coalition (WfMC) process definition metamodel [7]. A typical activity-based approach designs a workflow though a top-down decomposition procedure. This stepwise refinement allows a modeler to define a process more easily and completely than do one-step approaches. However, resultant layered process definitions do not always fit into an organizational hierarchy, despite providing several different levels of hierarchical abstraction. Therefore, hierarchically decomposing a process may not provide each organizational level with an appropriate view of that process. Despite forcing a process modeler to follow an organizational hierarchy while decomposing a process, different organizational units (divisions/companies) may have difficulties in obtaining adequate abstractions of the process/supply chain they participate in. The activity-based approach cannot adequately provide different participants with varied abstracted processes. The activity-based approach should be enhanced to provide different process abstractions. Several formal process modeling techniques, including process algebras and Petri Nets [8], [9], [10] and [11], can provide process abstractions by renaming activities to silent activities that are not observable. Such abstraction is considered as partial abstraction since it provides partial observability of a process. Although useful in satisfying some of the needs of process abstractions, partial abstraction may be unable to adequately address the needs of managers or collaborative parties who require aggregated information on a process. Based on the notion of views in database management systems (DBMSs), this work proposes a novel virtual workflow process, i.e., a process-view, in a WfMS. A process-view, i.e., an abstracted process derived from an implemented base process, is employed to provide aggregate abstraction of a process. During workflow build time, a process modeler does not need to be concerned with process abstraction, and can focus solely on process design, using a top-down decomposition procedure to define the process in detail. The modeler can then use a process-view definition tool to define multiple abstracted processes, i.e., process-views. During run time, creating a process instance initiates its corresponding process-view instances. Each participant can retrieve and monitor appropriate process information via the related process-view instance. Therefore, coordination within an organization or across multiple organizations can be improved. Although process design is a specialized and top-down procedure, process-view design is a generalized and bottom-up procedure. Process-views allow a WfMS to provide various aggregated views of a process for different levels or departments in an organization or for different organizations in a supply chain. Several approaches can be adopted to construct a process-view. This work describes a novel order-preserving approach in which the constructed process-view can preserve the original ordering of activities in the base process. A formal model is also presented to define an order-preserving process-view. Theoretical analysis is performed herein, indicating that the defined process-view satisfies the order-preserving property. Moreover, an algorithm is proposed to automatically generate an order-preserving process-view. The remainder of this paper is organized as follows. Section 2 formally defines business processes. Section 3 then describes and defines a process-view. Next, Section 4 presents the proposed order-preserving approach to construct a process-view. Section 5 then discusses and compares related work on workflow modeling. Conclusions and future work are finally made in Section 6. Appendix A provides proofs of all lemmas

6. Conclusion and future work This work proposes a novel concept of process abstraction: process-view. Process-view enhances the conventional activity-based model to satisfy the diverse needs for obtaining abstracted process information. A process modeler can easily use a process-view definition tool to provide numerous views of a business process for different levels, divisions, and enterprises. The process-view achieves information abstraction and progress monitoring. Each role can obtain adequate information on a business process by setting up a role-related process-view, thereby facilitating hierarchical coordination within an organizational unit and horizontal coordination across multiple organizations (internal or external). The proposed approach increases the flexibility and functionality of current WfMSs. Moreover, given the importance of execution order in business processes, this work also proposes an order-preserving approach to construct a process-view that preserves the original execution order of its base process. The proposed algorithm automatically derives minimal virtual activities and related virtual dependencies to generate an order-preserving process-view. The algorithm assists vendors in implementing process-view definition tools in their commercial systems. A real world example is used to demonstrate the feasibility of applying process-views. According to the atomicity rule, the execution state of a virtual activity is either started or completed. However, a base activity may have more semantic states such as suspended or aborted (i.e., abnormal completion) state. Determining the state of a virtual activity is difficult, for example, if the current states of its three member activities are suspended, started, and aborted. This problem becomes more complicated when a process modeler is allowed to define more application-specific activity states, such as CMI approach [3]. To express the progress information of process-views semantically, the issue of state abstraction requires further investigations. This work currently defines the produced/consumed data of a virtual activity as a set of the produced/consumed data of member activities. However, according to the demands of different roles, a process modeler may wish to define process-view relevant data as an aggregation of base process relevant data (e.g., summation or average), or a selected portion of base process relevant data. Furthermore, process relevant data may have various semantic meanings and definitions. For example, a sales order or an insurance contract have various semantics in different steps of their processing workflow. Abstracting process relevant data from these aspects is a difficult problem, and future enhancement should provide more advanced abstraction of process-view data.