Evolutionary Design through Reflective Petri Nets: an Application to Workflow

The design of dynamic workflows needs adequate modeling/specification formalisms and tools to soundly handle possible changes during workflow operation. A common approach is to pollute workflow design with details that do not regard the current behavior, but rather evolution. That hampers analysis, reuse and maintenance in general. We propose and discuss the adoption of a recent Petri netbased reflective model as a support to dynamic workflow design. Keeping separated functional aspects from evolution, results in a dynamic workflow model merging flexibility and ability of formally verifying basic workflow properties. A structural on-the-fly characterization of sound dynamic workflows is adopted based on Petri net’s freechoiceness preservation. An application is presented to a localized open problem: how to determine what tasks should be redone and which ones do not when transferring a workflow instance from an old to a new template.