ShapeCond: Fast Shapelet-Guided Dataset Condensation for Time Series Classification

Fuente: arXiv
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Main Authors: Peng, Sijia, Xiong, Yun, Chen, Xi, Xie, Yi, Li, Guanzhi, Yu, Yanwei, Zhu, Yangyong, Shen, Zhiqiang
Format: Preprint
Published: 2026
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author Peng, Sijia
Xiong, Yun
Chen, Xi
Xie, Yi
Li, Guanzhi
Yu, Yanwei
Zhu, Yangyong
Shen, Zhiqiang
author_facet Peng, Sijia
Xiong, Yun
Chen, Xi
Xie, Yi
Li, Guanzhi
Yu, Yanwei
Zhu, Yangyong
Shen, Zhiqiang
contents Time series data supports many domains (e.g., finance and climate science), but its rapid growth strains storage and computation. Dataset condensation can alleviate this by synthesizing a compact training set that preserves key information. Yet most condensation methods are image-centric and often fail on time series because they miss time-series-specific temporal structure, especially local discriminative motifs such as shapelets. In this work, we propose ShapeCond, a novel and efficient condensation framework for time series classification that leverages shapelet-based dataset knowledge via a shapelet-guided optimization strategy. Our shapelet-assisted synthesis cost is independent of sequence length: longer series yield larger speedups in synthesis (e.g., 29$\times$ faster over prior state-of-the-art method CondTSC for time-series condensation, and up to 10,000$\times$ over naively using shapelets on the Sleep dataset with 3,000 timesteps). By explicitly preserving critical local patterns, ShapeCond improves downstream accuracy and consistently outperforms all prior state-of-the-art time series dataset condensation methods across extensive experiments. Code is available at https://github.com/lunaaa95/ShapeCond.
format Preprint
id arxiv_https___arxiv_org_abs_2602_09008
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle ShapeCond: Fast Shapelet-Guided Dataset Condensation for Time Series Classification
Peng, Sijia
Xiong, Yun
Chen, Xi
Xie, Yi
Li, Guanzhi
Yu, Yanwei
Zhu, Yangyong
Shen, Zhiqiang
Machine Learning
Time series data supports many domains (e.g., finance and climate science), but its rapid growth strains storage and computation. Dataset condensation can alleviate this by synthesizing a compact training set that preserves key information. Yet most condensation methods are image-centric and often fail on time series because they miss time-series-specific temporal structure, especially local discriminative motifs such as shapelets. In this work, we propose ShapeCond, a novel and efficient condensation framework for time series classification that leverages shapelet-based dataset knowledge via a shapelet-guided optimization strategy. Our shapelet-assisted synthesis cost is independent of sequence length: longer series yield larger speedups in synthesis (e.g., 29$\times$ faster over prior state-of-the-art method CondTSC for time-series condensation, and up to 10,000$\times$ over naively using shapelets on the Sleep dataset with 3,000 timesteps). By explicitly preserving critical local patterns, ShapeCond improves downstream accuracy and consistently outperforms all prior state-of-the-art time series dataset condensation methods across extensive experiments. Code is available at https://github.com/lunaaa95/ShapeCond.
title ShapeCond: Fast Shapelet-Guided Dataset Condensation for Time Series Classification
topic Machine Learning
url https://arxiv.org/abs/2602.09008