SimAD: A Simple Dissimilarity-based Approach for Time Series Anomaly Detection

Fuente: arXiv
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Main Authors: Zhong, Zhijie, Yu, Zhiwen, Xi, Xing, Xu, Yue, Cao, Wenming, Yang, Yiyuan, Yang, Kaixiang, You, Jane
Format: Preprint
Published: 2024
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author Zhong, Zhijie
Yu, Zhiwen
Xi, Xing
Xu, Yue
Cao, Wenming
Yang, Yiyuan
Yang, Kaixiang
You, Jane
author_facet Zhong, Zhijie
Yu, Zhiwen
Xi, Xing
Xu, Yue
Cao, Wenming
Yang, Yiyuan
Yang, Kaixiang
You, Jane
contents Despite the prevalence of reconstruction-based deep learning methods, time series anomaly detection remains a tremendous challenge. Existing approaches often struggle with limited temporal contexts, insufficient representation of normal patterns, and flawed evaluation metrics, all of which hinder their effectiveness in detecting anomalous behavior. To address these issues, we introduce a $\textbf{Sim}$ple dissimilarity-based approach for time series $\textbf{A}$nomaly $\textbf{D}$etection, referred to as $\textbf{SimAD}$. Specifically, SimAD first incorporates a patching-based feature extractor capable of processing extended temporal windows and employs the EmbedPatch encoder to fully integrate normal behavioral patterns. Second, we design an innovative ContrastFusion module in SimAD, which strengthens the robustness of anomaly detection by highlighting the distributional differences between normal and abnormal data. Third, we introduce two robust enhanced evaluation metrics, Unbiased Affiliation (UAff) and Normalized Affiliation (NAff), designed to overcome the limitations of existing metrics by providing better distinctiveness and semantic clarity. The reliability of these two metrics has been demonstrated by both theoretical and experimental analyses. Experiments conducted on seven diverse time series datasets clearly demonstrate SimAD's superior performance compared to state-of-the-art methods, achieving relative improvements of $\textbf{19.85%}$ on F1, $\textbf{4.44%}$ on Aff-F1, $\textbf{77.79%}$ on NAff-F1, and $\textbf{9.69%}$ on AUC on six multivariate datasets. Code and pre-trained models are available at https://github.com/EmorZz1G/SimAD.
format Preprint
id arxiv_https___arxiv_org_abs_2405_11238
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle SimAD: A Simple Dissimilarity-based Approach for Time Series Anomaly Detection
Zhong, Zhijie
Yu, Zhiwen
Xi, Xing
Xu, Yue
Cao, Wenming
Yang, Yiyuan
Yang, Kaixiang
You, Jane
Machine Learning
Artificial Intelligence
Despite the prevalence of reconstruction-based deep learning methods, time series anomaly detection remains a tremendous challenge. Existing approaches often struggle with limited temporal contexts, insufficient representation of normal patterns, and flawed evaluation metrics, all of which hinder their effectiveness in detecting anomalous behavior. To address these issues, we introduce a $\textbf{Sim}$ple dissimilarity-based approach for time series $\textbf{A}$nomaly $\textbf{D}$etection, referred to as $\textbf{SimAD}$. Specifically, SimAD first incorporates a patching-based feature extractor capable of processing extended temporal windows and employs the EmbedPatch encoder to fully integrate normal behavioral patterns. Second, we design an innovative ContrastFusion module in SimAD, which strengthens the robustness of anomaly detection by highlighting the distributional differences between normal and abnormal data. Third, we introduce two robust enhanced evaluation metrics, Unbiased Affiliation (UAff) and Normalized Affiliation (NAff), designed to overcome the limitations of existing metrics by providing better distinctiveness and semantic clarity. The reliability of these two metrics has been demonstrated by both theoretical and experimental analyses. Experiments conducted on seven diverse time series datasets clearly demonstrate SimAD's superior performance compared to state-of-the-art methods, achieving relative improvements of $\textbf{19.85%}$ on F1, $\textbf{4.44%}$ on Aff-F1, $\textbf{77.79%}$ on NAff-F1, and $\textbf{9.69%}$ on AUC on six multivariate datasets. Code and pre-trained models are available at https://github.com/EmorZz1G/SimAD.
title SimAD: A Simple Dissimilarity-based Approach for Time Series Anomaly Detection
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2405.11238