Simple models for articulating complex work processes

Abstract

Adaptability of workflow models can be achieved if the specification module of the Workflow Management System (WMS) is based on a theoretical kernel, allowing minimal effort for the creation of a workflow model capable of providing, when necessary, any view (and the related services) the users may want of it. The specification module of the Milano WMS has been developed on the basis of the above assumption [2, 3], so that it supports the articulation of complex work processes. Milano [1] is a system integrating in the user workspace a WMS with a multimedia conversation handler, and, finally, an object repository where an organizational handbook is stored.The workflow models of Milano constitute a small subcategory of ENS (Elementary Net Systems), namely Free-Choice Acyclic ENS. Free-choice Acyclic ENS have some nice, efficiently computable, properties: there is a synthesis algorithm from Elementary Transition Systems (ETS) to ENS so that the user can have different views of the workflow; it is possible to compute and classify the jumps recovering exceptions; morphisms between models allow an efficient correctness check for changes and support on-the-fly enactment of changes. The formal aspects of the Milano WMS are described in [2, 3]. Figure 1 presents the Workflow Net Model (WNM) (in the state {b4, b9}) of the first part of a Credit Procedure.