Authors:
Lucas Correia
1
;
2
;
Jan-Christoph Goos
1
;
Philipp Klein
1
;
Thomas Bäck
2
and
Anna Kononova
2
Affiliations:
1
Mercedes-Benz AG, Stuttgart, Germany
;
2
Leiden University, Leiden, The Netherlands
Keyword(s):
Anomaly Detection, Multivariate, Time Series, Automotive, Test Bench, Variational Autoencoder, Bypass Phenomenon.
Abstract:
A clear need for automatic anomaly detection applied to automotive testing has emerged as more and more attention is paid to the data recorded and manual evaluation by humans reaches its capacity. Such real-world data is massive, diverse, multivariate and temporal in nature, therefore requiring modelling of the testee behaviour. We propose a variational autoencoder with multi-head attention (MA-VAE), which, when trained on unlabelled data, not only provides very few false positives but also manages to detect the majority of the anomalies presented. In addition to that, the approach offers a novel way to avoid the bypass phenomenon, an undesirable behaviour investigated in literature. Lastly, the approach also introduces a new method to remap individual windows to a continuous time series. The results are presented in the context of a real-world in-dustrial data set and several experiments are undertaken to further investigate certain aspects of the proposed model. When configured pro
perly, it is 9% of the time wrong when an anomaly is flagged and discovers 67% of the anomalies present. Also, MA-VAE has the potential to perform well with only a fraction of the training and validation subset, however, to extract it, a more sophisticated threshold estimation method is required.
(More)