The positions are within dr. Sicco Verwer's recently funded VIDI project "Learning state machines from infrequent software traces". The project goal is research and develop novel model learning algorithms and develop tools for learning from software log data. The aim is to provide software analysts with insightful models. We are able to learn insightful state machine models for the frequent happy flow of software. Although these can be useful to understand software, the real interesting behavior occurs in the infrequent unhappy flows, typically caused by errors.