Geometric-Based Pruning Rules For Change Point Detection in Multiple Independent Time Series

Fuente: arXiv
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Main Authors: Pishchagina, Liudmila, Rigaill, Guillem, Runge, Vincent
Format: Preprint
Published: 2023
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author Pishchagina, Liudmila
Rigaill, Guillem
Runge, Vincent
author_facet Pishchagina, Liudmila
Rigaill, Guillem
Runge, Vincent
contents We consider the problem of detecting multiple changes in multiple independent time series. The search for the best segmentation can be expressed as a minimization problem over a given cost function. We focus on dynamic programming algorithms that solve this problem exactly. When the number of changes is proportional to data length, an inequality-based pruning rule encoded in the PELT algorithm leads to a linear time complexity. Another type of pruning, called functional pruning, gives a close-to-linear time complexity whatever the number of changes, but only for the analysis of univariate time series. We propose a few extensions of functional pruning for multiple independent time series based on the use of simple geometric shapes (balls and hyperrectangles). We focus on the Gaussian case, but some of our rules can be easily extended to the exponential family. In a simulation study we compare the computational efficiency of different geometric-based pruning rules. We show that for small dimensions (2, 3, 4) some of them ran significantly faster than inequality-based approaches in particular when the underlying number of changes is small compared to the data length.
format Preprint
id arxiv_https___arxiv_org_abs_2306_09555
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Geometric-Based Pruning Rules For Change Point Detection in Multiple Independent Time Series
Pishchagina, Liudmila
Rigaill, Guillem
Runge, Vincent
Methodology
Computation
Machine Learning
We consider the problem of detecting multiple changes in multiple independent time series. The search for the best segmentation can be expressed as a minimization problem over a given cost function. We focus on dynamic programming algorithms that solve this problem exactly. When the number of changes is proportional to data length, an inequality-based pruning rule encoded in the PELT algorithm leads to a linear time complexity. Another type of pruning, called functional pruning, gives a close-to-linear time complexity whatever the number of changes, but only for the analysis of univariate time series. We propose a few extensions of functional pruning for multiple independent time series based on the use of simple geometric shapes (balls and hyperrectangles). We focus on the Gaussian case, but some of our rules can be easily extended to the exponential family. In a simulation study we compare the computational efficiency of different geometric-based pruning rules. We show that for small dimensions (2, 3, 4) some of them ran significantly faster than inequality-based approaches in particular when the underlying number of changes is small compared to the data length.
title Geometric-Based Pruning Rules For Change Point Detection in Multiple Independent Time Series
topic Methodology
Computation
Machine Learning
url https://arxiv.org/abs/2306.09555