Cross-aligned and Gumbel-refactored Autoencoders for Multi-view Anomaly Detection

Publisher:
IEEE
Publication Type:
Conference Proceeding
Citation:
2021 IEEE 33rd International Conference on Tools with Artificial Intelligence (ICTAI), 2021, 2021-November, pp. 1368-1375
Issue Date:
2021-12-21
Full metadata record
Multi-view anomaly detection (AD) is a challenging task due to the complicated data distributions across different views. Specifically, there exist two types of anomalies in multi-view distributions: attribute anomaly that exhibits consistent anomalous pattern in each view and class anomaly that exhibits inconsistent traits (e.g., semantic label) across multiple views. Existing methods detect these anomalies in an unsupervised manner with the clustering assumption: normal data share consistent clustering structure across views while anomalous data exhibits inconsistent clusters across views. However, these methods would fail for complex multi-view data distributions where there is no obvious clusters. Moreover, existing models suffer from robustness since they are undermined by anomalies during training time. To get rid of the clustering assumption, we propose a Cross-aligned and Gumbel-refactored AutoEncoders (CGAEs) model to effectively detect two types of multi-view anomalies. In CGAEs, we devise a cross-reconstruction module to detect class anomaly by recovering one view from another view. Class anomalies would lead to high cross-reconstruction loss since they do not have the correct information in one view to generate another. We further design a view-alignment module to detect attribute anomaly by the alignment distance among multiple views in the latent space. Attribute anomalies possess large distances since they are less aligned due to fewer anomalous training instances. To handle the robustness issue, we propose a Gumbel-refactored reconstruction loss to replace the mean square error (MSE) in original autoencoders. The cross entropy loss is calculated between the discreterized input and Gumbel-sampled output, thus disregarding the irrelevant details to achieve model robustness. Experimental results validate the superiority of the proposed CGAEs model on both the benchmark datasets and real world datasets.
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