Fast and Optimal Changepoint Detection and Localization using Bonferroni Triplets

Fuente: arXiv
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Main Authors: Jang, Jayoon, Walther, Guenther
Format: Preprint
Published: 2024
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author Jang, Jayoon
Walther, Guenther
author_facet Jang, Jayoon
Walther, Guenther
contents The paper considers the problem of detecting and localizing changepoints in a sequence of independent observations. We propose to evaluate a local test statistic on a triplet of time points, for each such triplet in a particular collection. This collection is sparse enough so that the results of the local tests can simply be combined with a weighted Bonferroni correction. This results in a simple and fast method, {\sl Lean Bonferroni Changepoint detection} (LBD), that provides finite sample guarantees for the existance of changepoints as well as simultaneous confidence intervals for their locations. LBD is free of tuning parameters, and we show that LBD allows optimal inference for the detection of changepoints. To this end, we provide a lower bound for the critical constant that measures the difficulty of the changepoint detection problem, and we show that LBD attains this critical constant. We illustrate LBD for a number of distributional settings, namely when the observations are homoscedastic normal with known or unknown variance, for observations from a natural exponential family, and in a nonparametric setting where we assume only exchangeability for segments without a changepoint.
format Preprint
id arxiv_https___arxiv_org_abs_2410_14866
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Fast and Optimal Changepoint Detection and Localization using Bonferroni Triplets
Jang, Jayoon
Walther, Guenther
Methodology
The paper considers the problem of detecting and localizing changepoints in a sequence of independent observations. We propose to evaluate a local test statistic on a triplet of time points, for each such triplet in a particular collection. This collection is sparse enough so that the results of the local tests can simply be combined with a weighted Bonferroni correction. This results in a simple and fast method, {\sl Lean Bonferroni Changepoint detection} (LBD), that provides finite sample guarantees for the existance of changepoints as well as simultaneous confidence intervals for their locations. LBD is free of tuning parameters, and we show that LBD allows optimal inference for the detection of changepoints. To this end, we provide a lower bound for the critical constant that measures the difficulty of the changepoint detection problem, and we show that LBD attains this critical constant. We illustrate LBD for a number of distributional settings, namely when the observations are homoscedastic normal with known or unknown variance, for observations from a natural exponential family, and in a nonparametric setting where we assume only exchangeability for segments without a changepoint.
title Fast and Optimal Changepoint Detection and Localization using Bonferroni Triplets
topic Methodology
url https://arxiv.org/abs/2410.14866