When Model Meets New Normals: Test-time Adaptation for Unsupervised Time-series Anomaly Detection

Fuente: arXiv
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Main Authors: Kim, Dongmin, Park, Sunghyun, Choo, Jaegul
Format: Preprint
Published: 2023
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author Kim, Dongmin
Park, Sunghyun
Choo, Jaegul
author_facet Kim, Dongmin
Park, Sunghyun
Choo, Jaegul
contents Time-series anomaly detection deals with the problem of detecting anomalous timesteps by learning normality from the sequence of observations. However, the concept of normality evolves over time, leading to a "new normal problem", where the distribution of normality can be changed due to the distribution shifts between training and test data. This paper highlights the prevalence of the new normal problem in unsupervised time-series anomaly detection studies. To tackle this issue, we propose a simple yet effective test-time adaptation strategy based on trend estimation and a self-supervised approach to learning new normalities during inference. Extensive experiments on real-world benchmarks demonstrate that incorporating the proposed strategy into the anomaly detector consistently improves the model's performance compared to the baselines, leading to robustness to the distribution shifts.
format Preprint
id arxiv_https___arxiv_org_abs_2312_11976
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle When Model Meets New Normals: Test-time Adaptation for Unsupervised Time-series Anomaly Detection
Kim, Dongmin
Park, Sunghyun
Choo, Jaegul
Machine Learning
Artificial Intelligence
Time-series anomaly detection deals with the problem of detecting anomalous timesteps by learning normality from the sequence of observations. However, the concept of normality evolves over time, leading to a "new normal problem", where the distribution of normality can be changed due to the distribution shifts between training and test data. This paper highlights the prevalence of the new normal problem in unsupervised time-series anomaly detection studies. To tackle this issue, we propose a simple yet effective test-time adaptation strategy based on trend estimation and a self-supervised approach to learning new normalities during inference. Extensive experiments on real-world benchmarks demonstrate that incorporating the proposed strategy into the anomaly detector consistently improves the model's performance compared to the baselines, leading to robustness to the distribution shifts.
title When Model Meets New Normals: Test-time Adaptation for Unsupervised Time-series Anomaly Detection
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2312.11976