A History Equivalence Algorithm for Dynamic Process Migration

Dynamic changes in processes necessitate the notion of state equivalence between the old and new workflows. In several cases, the history of the workflow to be migrated provides sufficient context for a meaningful migration. In this paper, we present an algorithm to find the equivalence mapping for states from the old workflow to the new one using a trail-based consistency model called history equivalence. The algorithm finds history equivalent mappings for all migratable states in the reachability graph of the process under migration. It also reports all non-migratable states that fall in the change region for a given pair of old and new Petri Nets. The paper presents the algorithm, its working, and an intuitive proof. The working is demonstrated through a couple of illustrations.