Discovering Hierarchical Processes Using Flexible Activity Trees for Event Abstraction

In this work, we propose FlexHMiner (FH), a three-step approach for the discovery of hierarchal models. We formalize the concept of activity tree and event abstraction, which allows us to be flexible in the ways of computing the process hierarchy. We illustrate this flexibility by proposing three different techniques to discover an activity tree: (1) a fully domain based approach (DK-FH), (2) a random approach (RC-FH), and (3) a fall-back, flat activity tree (F-FH). After obtaining an activity tree, the second step of our approach is to compute the logs for each subprocess using log abstraction and log projection. Finally, FlexHMiner discovers a subprocess model for each subprocess by leveraging the capabilities of existing discovery algorithms. Using the domain-based approach as the gold standard and the flat tree approach as base line, we compare the three ways of discovering an activity tree using seven real-life logs.