A Shapelet-based Framework for Unsupervised Multivariate Time Series Representation Learning

Fuente: arXiv
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Autores principales: Liang, Zhiyu, Zhang, Jianfeng, Liang, Chen, Wang, Hongzhi, Liang, Zheng, Pan, Lujia
Formato: Preprint
Publicado: 2023
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author Liang, Zhiyu
Zhang, Jianfeng
Liang, Chen
Wang, Hongzhi
Liang, Zheng
Pan, Lujia
author_facet Liang, Zhiyu
Zhang, Jianfeng
Liang, Chen
Wang, Hongzhi
Liang, Zheng
Pan, Lujia
contents Recent studies have shown great promise in unsupervised representation learning (URL) for multivariate time series, because URL has the capability in learning generalizable representation for many downstream tasks without using inaccessible labels. However, existing approaches usually adopt the models originally designed for other domains (e.g., computer vision) to encode the time series data and {rely on strong assumptions to design learning objectives, which limits their ability to perform well}. To deal with these problems, we propose a novel URL framework for multivariate time series by learning time-series-specific shapelet-based representation through a popular contrasting learning paradigm. To the best of our knowledge, this is the first work that explores the shapelet-based embedding in the unsupervised general-purpose representation learning. A unified shapelet-based encoder and a novel learning objective with multi-grained contrasting and multi-scale alignment are particularly designed to achieve our goal, and a data augmentation library is employed to improve the generalization. We conduct extensive experiments using tens of real-world datasets to assess the representation quality on many downstream tasks, including classification, clustering, and anomaly detection. The results demonstrate the superiority of our method against not only URL competitors, but also techniques specially designed for downstream tasks. Our code has been made publicly available at https://github.com/real2fish/CSL.
format Preprint
id arxiv_https___arxiv_org_abs_2305_18888
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle A Shapelet-based Framework for Unsupervised Multivariate Time Series Representation Learning
Liang, Zhiyu
Zhang, Jianfeng
Liang, Chen
Wang, Hongzhi
Liang, Zheng
Pan, Lujia
Machine Learning
Recent studies have shown great promise in unsupervised representation learning (URL) for multivariate time series, because URL has the capability in learning generalizable representation for many downstream tasks without using inaccessible labels. However, existing approaches usually adopt the models originally designed for other domains (e.g., computer vision) to encode the time series data and {rely on strong assumptions to design learning objectives, which limits their ability to perform well}. To deal with these problems, we propose a novel URL framework for multivariate time series by learning time-series-specific shapelet-based representation through a popular contrasting learning paradigm. To the best of our knowledge, this is the first work that explores the shapelet-based embedding in the unsupervised general-purpose representation learning. A unified shapelet-based encoder and a novel learning objective with multi-grained contrasting and multi-scale alignment are particularly designed to achieve our goal, and a data augmentation library is employed to improve the generalization. We conduct extensive experiments using tens of real-world datasets to assess the representation quality on many downstream tasks, including classification, clustering, and anomaly detection. The results demonstrate the superiority of our method against not only URL competitors, but also techniques specially designed for downstream tasks. Our code has been made publicly available at https://github.com/real2fish/CSL.
title A Shapelet-based Framework for Unsupervised Multivariate Time Series Representation Learning
topic Machine Learning
url https://arxiv.org/abs/2305.18888