Grünhagen, ArneArneGrünhagenEichler, AnnikaAnnikaEichlerTropmann-Frick, MarinaMarinaTropmann-FrickFey, GörschwinGörschwinFey2025-11-212025-11-212025Frontiers in artificial intelligence and applications 399: 129-145 (2025)https://hdl.handle.net/11420/58920The early and automatic detection of faulty behavior is essential for maintaining the reliability of a cyber-physical system. In this paper we describe a fault localization approach for such a highly complex distributed system, the optical synchronization system of the European X-ray free-electron laser. Using a dependency graph, we model the relationships between the components and the influences of environmental effects. After we first resolve linear long-term dependencies between dependent components with a correlation analysis, we then use an unsupervised fault detection pipeline consisting of statistical feature extraction and unsupervised anomaly detection to accurately identify anomalies and localize their origins in the system.enhttps://creativecommons.org/licenses/by-nc/4.0/Data MiningFault AnalysisDependency GraphCyber-Physical SystemComputer Science, Information and General Works::005: Computer Programming, Programs, Data and Security::005.8: Computer SecurityTechnology::620: EngineeringBook Parthttps://doi.org/10.15480/882.1619210.3233/FAIA24157710.15480/882.16192Book Chapter