Computing Alignments for Partially-ordered Traces Through Petri Net Unfoldings

Conformance checking techniques aim to provide diagnostics on the conformity between process models and event data. Conventional methods, such as trace alignments, assume strict total ordering of events, leading to inaccuracies when timestamps are overlapping, coarse, or missing. In contrast, existing methods that support partially ordered events rely upon the interleaving semantics of Petri nets, the reachability graphs, which suffer from the state space explosion problem. %Besides, this view also forces the solution to create a partially ordered alignment almost artificially. This paper proposes an improved approach to conformance checking based upon partially ordered event data by utilizing Petri net unfolding, which leverages partial-order semantics of Petri nets to represent concurrency and uncertainty in event logs more effectively. Unlike existing methods, our approach offers a streamlined one-step solution, improving efficiency in the computation of alignments. Additionally, we introduce a novel visualization technique for partially ordered unfolding-based alignments. We implement unfolding-based alignments with its user-friendly insights in a conformance analysis tool. Our experimental evaluation, conducted on synthetic and real-world event logs, demonstrates that the unfolding-based approach is particularly robust in handling high degrees of parallelism and complexity in process models.