In: J. Esparza, C. Lakos (Eds.): Lecture Notes in Computer Science, Vol. 2360: 23rd International Conference on Applications and Theory of Petri Nets, Adelaide, Australia, June 24-30, 2002, pages 1-394pp. Springer Verlag, June 2002.
Abstract: We propose extensions to predicate/transition nets to allow tokens to carry both data and control information, where such control can refine special `` refinable place nodes'' in the net. These formal extensions find use in active document workflow, in which documents themselves specify portions of the overall processing within a workflow net. Our approach enables the workflow designer to specify which places of the target predicate/transition net may be refined and it enables the document author to specify how these places will be refined (via attachment of a token-generated `` refinement net'' ). This apportionment of the overall task allows the workflow designer to set general constraints within which the document author can control the processing; it prevents conflicts between them in foreseeable practical cases. Refinable places are augmented with a permission structure specifying which document authors can refine that place and which document tokens can execute a node's refinement net. Our refined nets have a hierarchical structure which can be represented by bipartite trees.