Low Rank Transformer for Multivariate Time Series Anomaly Detection and Localization

Fuente: arXiv
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Main Authors: Shimillas, Charalampos, Malialis, Kleanthis, Fokianos, Konstantinos, Polycarpou, Marios M.
Format: Preprint
Published: 2026
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author Shimillas, Charalampos
Malialis, Kleanthis
Fokianos, Konstantinos
Polycarpou, Marios M.
author_facet Shimillas, Charalampos
Malialis, Kleanthis
Fokianos, Konstantinos
Polycarpou, Marios M.
contents Multivariate time series (MTS) anomaly diagnosis, which encompasses both anomaly detection and localization, is critical for the safety and reliability of complex, large-scale real-world systems. The vast majority of existing anomaly diagnosis methods offer limited theoretical insights, especially for anomaly localization, which is a vital but largely unexplored area. The aim of this contribution is to study the learning process of a Transformer when applied to MTS by revealing connections to statistical time series methods. Based on these theoretical insights, we propose the Attention Low-Rank Transformer (ALoRa-T) model, which applies low-rank regularization to self-attention, and we introduce the Attention Low-Rank score, effectively capturing the temporal characteristics of anomalies. Finally, to enable anomaly localization, we propose the ALoRa-Loc method, a novel approach that associates anomalies to specific variables by quantifying interrelationships among time series. Extensive experiments and real data analysis, show that the proposed methodology significantly outperforms state-of-the-art methods in both detection and localization tasks.
format Preprint
id arxiv_https___arxiv_org_abs_2602_08467
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Low Rank Transformer for Multivariate Time Series Anomaly Detection and Localization
Shimillas, Charalampos
Malialis, Kleanthis
Fokianos, Konstantinos
Polycarpou, Marios M.
Machine Learning
Multivariate time series (MTS) anomaly diagnosis, which encompasses both anomaly detection and localization, is critical for the safety and reliability of complex, large-scale real-world systems. The vast majority of existing anomaly diagnosis methods offer limited theoretical insights, especially for anomaly localization, which is a vital but largely unexplored area. The aim of this contribution is to study the learning process of a Transformer when applied to MTS by revealing connections to statistical time series methods. Based on these theoretical insights, we propose the Attention Low-Rank Transformer (ALoRa-T) model, which applies low-rank regularization to self-attention, and we introduce the Attention Low-Rank score, effectively capturing the temporal characteristics of anomalies. Finally, to enable anomaly localization, we propose the ALoRa-Loc method, a novel approach that associates anomalies to specific variables by quantifying interrelationships among time series. Extensive experiments and real data analysis, show that the proposed methodology significantly outperforms state-of-the-art methods in both detection and localization tasks.
title Low Rank Transformer for Multivariate Time Series Anomaly Detection and Localization
topic Machine Learning
url https://arxiv.org/abs/2602.08467