A spectral approach for online covariance change point detection

Fuente: arXiv
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Auteurs principaux: Bao, Zhigang, Cheong, Kha Man, Li, Yuji, Qiu, Jiaxin
Format: Preprint
Publié: 2026
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author Bao, Zhigang
Cheong, Kha Man
Li, Yuji
Qiu, Jiaxin
author_facet Bao, Zhigang
Cheong, Kha Man
Li, Yuji
Qiu, Jiaxin
contents Change point detection in covariance structures is a fundamental and crucial problem for sequential data. Under the high-dimensional setting, most of the existing research has focused on identifying change points in historical data. However, there is a significant lack of studies on the practically relevant online change point problem, which means promptly detecting change points as they occur. In this paper, applying the limiting theory of linear spectral statistics for random matrices, we propose a class of spectrum based CUSUM-type statistic. We first construct a martingale from the difference of linear spectral statistics of sequential sample Fisher matrices, which converges to a Brownian motion. Our CUSUM-type statistic is then defined as the maximum of a variant of this process. Finally, we develop our detection procedure based on the invariance principle. Simulation results show that our detection method is highly sensitive to the occurrence of change point and is able to identify it shortly after they arise, outperforming the existing approaches.
format Preprint
id arxiv_https___arxiv_org_abs_2601_22602
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A spectral approach for online covariance change point detection
Bao, Zhigang
Cheong, Kha Man
Li, Yuji
Qiu, Jiaxin
Statistics Theory
Methodology
Change point detection in covariance structures is a fundamental and crucial problem for sequential data. Under the high-dimensional setting, most of the existing research has focused on identifying change points in historical data. However, there is a significant lack of studies on the practically relevant online change point problem, which means promptly detecting change points as they occur. In this paper, applying the limiting theory of linear spectral statistics for random matrices, we propose a class of spectrum based CUSUM-type statistic. We first construct a martingale from the difference of linear spectral statistics of sequential sample Fisher matrices, which converges to a Brownian motion. Our CUSUM-type statistic is then defined as the maximum of a variant of this process. Finally, we develop our detection procedure based on the invariance principle. Simulation results show that our detection method is highly sensitive to the occurrence of change point and is able to identify it shortly after they arise, outperforming the existing approaches.
title A spectral approach for online covariance change point detection
topic Statistics Theory
Methodology
url https://arxiv.org/abs/2601.22602