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Abstract : |
The workflow technology has been an active area of research for the past few years. The conceptual modeling of workflows is the first, and arguably the most important, step towards understanding business processes. A well defined workflow conceptual model leads to the development of an effective workflow application. This paper presents a graphical modeling technique for workflows. We introduce four graphical modeling objects: tasks, conditions, synchronizers, and flows. The tasks represent the primary modeling concept and could be classified through several generic and workflow specific characteristics, some of which have been identified in this paper. Using the four modeling objects, the following workflow modeling constructs are identified: ordering, alternative, exclusive join, concurrency, synchronization, iteration, start/stop, nesting, and contingency. It is possible to easily get into error situations while building large workflow specifications. We present a set of constraints for ensuring the correctness of workflow specifications. A brief introduction to the concept of task compensation and task structures is given. We also apply the proposed conceptual modeling technique to model an example document workflows application for handling postgraduate admission process of a university. The concepts introduced in this paper are applied as a foundation to the development of a CASE tool for the modeling and syntactical verification of workflow, |
