Conformance checking -- a branch of process mining -- focuses on establishing to what extent actual executions of a process are in line with the expected behavior of a reference model. Current conformance checking techniques only allow for a-posteriori analysis: the amount of (non-)conformant behavior is quantied after the completion of the process instance. In this paper we propose a framework for online conformance checking: not only we quantify (non-)conformant behavior as the execution is running, we also restrict the computation to constant time complexity per event analyzed, thus enabling the online analysis of a stream of events. The framework is instantiated with ideas coming from the theory of regions, and state similarity. An implementation is available in ProM and promising results have been obtained.
Published in Proceedings of the 13th International Workshop on Business Process Intelligence (BPI 2017); September 10-11, 2017.