RoCA: Robust Contrastive One-class Time Series Anomaly Detection with Contaminated Data

Fuente: arXiv
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Main Authors: Mou, Xudong, Wang, Rui, Li, Bo, Wo, Tianyu, Sun, Jie, Wang, Hui, Liu, Xudong
Format: Preprint
Published: 2025
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author Mou, Xudong
Wang, Rui
Li, Bo
Wo, Tianyu
Sun, Jie
Wang, Hui
Liu, Xudong
author_facet Mou, Xudong
Wang, Rui
Li, Bo
Wo, Tianyu
Sun, Jie
Wang, Hui
Liu, Xudong
contents The accumulation of time-series signals and the absence of labels make time-series Anomaly Detection (AD) a self-supervised task of deep learning. Methods based on normality assumptions face the following three limitations: (1) A single assumption could hardly characterize the whole normality or lead to some deviation. (2) Some assumptions may go against the principle of AD. (3) Their basic assumption is that the training data is uncontaminated (free of anomalies), which is unrealistic in practice, leading to a decline in robustness. This paper proposes a novel robust approach, RoCA, which is the first to address all of the above three challenges, as far as we are aware. It fuses the separated assumptions of one-class classification and contrastive learning in a single training process to characterize a more complete so-called normality. Additionally, it monitors the training data and computes a carefully designed anomaly score throughout the training process. This score helps identify latent anomalies, which are then used to define the classification boundary, inspired by the concept of outlier exposure. The performance on AIOps datasets improved by 6% compared to when contamination was not considered (COCA). On two large and high-dimensional multivariate datasets, the performance increased by 5% to 10%. RoCA achieves the highest average performance on both univariate and multivariate datasets. The source code is available at https://github.com/ruiking04/RoCA.
format Preprint
id arxiv_https___arxiv_org_abs_2503_18385
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle RoCA: Robust Contrastive One-class Time Series Anomaly Detection with Contaminated Data
Mou, Xudong
Wang, Rui
Li, Bo
Wo, Tianyu
Sun, Jie
Wang, Hui
Liu, Xudong
Machine Learning
Artificial Intelligence
The accumulation of time-series signals and the absence of labels make time-series Anomaly Detection (AD) a self-supervised task of deep learning. Methods based on normality assumptions face the following three limitations: (1) A single assumption could hardly characterize the whole normality or lead to some deviation. (2) Some assumptions may go against the principle of AD. (3) Their basic assumption is that the training data is uncontaminated (free of anomalies), which is unrealistic in practice, leading to a decline in robustness. This paper proposes a novel robust approach, RoCA, which is the first to address all of the above three challenges, as far as we are aware. It fuses the separated assumptions of one-class classification and contrastive learning in a single training process to characterize a more complete so-called normality. Additionally, it monitors the training data and computes a carefully designed anomaly score throughout the training process. This score helps identify latent anomalies, which are then used to define the classification boundary, inspired by the concept of outlier exposure. The performance on AIOps datasets improved by 6% compared to when contamination was not considered (COCA). On two large and high-dimensional multivariate datasets, the performance increased by 5% to 10%. RoCA achieves the highest average performance on both univariate and multivariate datasets. The source code is available at https://github.com/ruiking04/RoCA.
title RoCA: Robust Contrastive One-class Time Series Anomaly Detection with Contaminated Data
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2503.18385