SimAD: A Simple Dissimilarity-based Approach for Time Series Anomaly Detection
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Abstract (arXiv)
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 Simple dissimilarity-based approach for time series Anomaly Detection, referred to as 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 19.85% on F1, 4.44% on Aff-F1, 77.79% on NAff-F1, and 9.69% on AUC on six multivariate datasets. Code and pre-trained models are available at https://github.com/EmorZz1G/SimAD.
Key facts. Cited by 6 papers in the map (data through 14 Oct 2026). Builds on 32 of its 72 references that are in the map. First posted on arXiv 18 May 2024.
Builds on
32 of 72 references.
References · 32
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20 more
- 2023SimpleNet: A Simple Network for Image Anomaly Detection and Localizationcited by 256
- 2022TranAD: Deep Transformer Networks for Anomaly Detection in Multivariate Time Series Datacited by 214
- 2023Frequency-domain MLPs are More Effective Learners in Time Series Forecastingcited by 172
- 2020Current Time Series Anomaly Detection Benchmarks are Flawed and are Creating the Illusion of Progresscited by 151
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- 2023DCdetector: Dual Attention Contrastive Representation Learning for Time Series Anomaly Detectioncited by 103
- 2021Towards a Rigorous Evaluation of Time-series Anomaly Detectioncited by 97
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Built on by
Citing papers per year: 2025: 4; 2026: 2.
6 papers.
- 2025STAR: Boosting Time Series Foundation Models for Anomaly Detection through State-aware Adaptercited by 7
- 2025CCE: Confidence-Consistency Evaluation for Time Series Anomaly Detectioncited by 0
- 2025Pi-transformer: A prior-informed dual-attention model for multivariate time-series anomaly detectioncited by 0
- 2025PathFinder: Advancing Path Loss Prediction for Single-to-Multi-Transmitter Scenariocited by 0
- 2026PaAno+: Multiscale Encoding and Cross-Variable Attention for Time Series Anomaly Detectioncited by 0
- 2026Did We Actually Fix It? An Independent Adversarial Stress-Test of Post-Point-Adjustment Evaluation Metrics for Time-Series Anomaly Detectioncited by 0
- 2026Did We Actually Fix It? An Independent Adversarial Stress-Test of Post-Point-Adjustment Evaluation Metrics for Time-Series Anomaly Detection12 Jul 2026
- 2026PaAno+: Multiscale Encoding and Cross-Variable Attention for Time Series Anomaly Detection18 Jun 2026
- 2025PathFinder: Advancing Path Loss Prediction for Single-to-Multi-Transmitter Scenario16 Dec 2025
- 2025STAR: Boosting Time Series Foundation Models for Anomaly Detection through State-aware Adapter15 Oct 2025
- 2025Pi-transformer: A prior-informed dual-attention model for multivariate time-series anomaly detection24 Sep 2025
- 2025CCE: Confidence-Consistency Evaluation for Time Series Anomaly Detection1 Sep 2025