Jochen Kuester of IBM Zurich Research presented a paper on Detecting and Resolving Process Model Differences in the Absence of a Change Log, co-authored by Christian Gerth, Alexander Foerster and Gregor Engels. Detecting differences would be done in the case where a process model is changed, and there is a need to detect and resolve the differences between the models. They focus on detection, visualization and resolution of differences between the process models.
Detection of differences between process model, which involves reconstructing the change log that transforms one version to another. This is done by computing fragments for the process models similar to the process structure tree methods that we saw from other IBM researches yesterday, then identifying elements that are identical in both models (even if in a different part of the model), elements that are in the first model but not the second, and those that are in the second model but not the first. This allows correspondences to be derived for the fragments in the process structure tree. From there, they can detect differences in actions/fragments, whether an insertion, deletion or move of an action within or between fragments.
They have a grammar of compound operations describing these differences, which can now be used to create a change log by creating a joint process structure tree formed by combining the process structure tree of both models, tagging the nodes with the operations, and determining the position parameters of each of the operations.
They’ve prototyped this in IBM WebSphere Process Modeler.