Scoring Message Stream Anomalies in Railway Communication Systems
Lucas Foulon, Serge Fenet, Christophe Rigotti, Denis Jouvin · 2019
This work focuses on the detection of anomalies in a railway communication system. We present the detection method as well as the architecture of the system supporting it. The method is based on a preliminary stage to collect and aggregate the data. It then combines the use of a multidimensional indexation tree (i.e., iSax tree) to store time series, and the computation of an anomaly detection score (i.e., CFOF score). We propose a fast estimation of this anomaly score, based on the information stored in the indexation tree, so that the score can therefore be computed on the fly over the stream of messages in the communication system. We show by mean of experiments that this estimation is close to the exact score. We describe the platform that has been implemented, and we show that it effectively support abnormal behaviour detection in the real stream of messages within the communication system of the French Railway Company (SNCF).