TimeMAE: Self-Supervised Representations of Time Series with Decoupled Masked Autoencoders

Fuente: arXiv
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Autori principali: Cheng, Mingyue, Tao, Xiaoyu, Liu, Zhiding, Liu, Qi, Zhang, Hao, Zhang, Rujiao, Chen, Enhong
Natura: Preprint
Pubblicazione: 2023
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author Cheng, Mingyue
Tao, Xiaoyu
Liu, Zhiding
Liu, Qi
Zhang, Hao
Zhang, Rujiao
Chen, Enhong
author_facet Cheng, Mingyue
Tao, Xiaoyu
Liu, Zhiding
Liu, Qi
Zhang, Hao
Zhang, Rujiao
Chen, Enhong
contents Learning transferable representations from unlabeled time series is crucial for improving performance in data-scarce classification. Existing self-supervised methods often operate at the point level and rely on unidirectional encoding, leading to low semantic density and a mismatch between pre-training and downstream optimization. In this paper, we propose TimeMAE, a self-supervised framework that reformulates masked modeling for time series via semantic unit elevation and decoupled representation learning. Instead of modeling individual time steps, TimeMAE segments time series into non-overlapping sub-series to form semantically enriched units, enabling more informative masked reconstruction while reducing computational cost. To address the representation discrepancy introduced by masking, we design a decoupled masked autoencoder that separately encodes visible and masked regions, avoiding artificial masked tokens in the main encoder. To guide pre-training, we introduce two complementary objectives: masked codeword classification, which discretizes sub-series semantics via a learned tokenizer and masked representation regression, which aligns continuous representations through a momentum-updated target encoder. Extensive experiments on five datasets demonstrate that TimeMAE outperforms competitive baselines, particularly in label-scarce scenarios and transfer learning scenarios.
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publishDate 2023
record_format arxiv
spellingShingle TimeMAE: Self-Supervised Representations of Time Series with Decoupled Masked Autoencoders
Cheng, Mingyue
Tao, Xiaoyu
Liu, Zhiding
Liu, Qi
Zhang, Hao
Zhang, Rujiao
Chen, Enhong
Machine Learning
Learning transferable representations from unlabeled time series is crucial for improving performance in data-scarce classification. Existing self-supervised methods often operate at the point level and rely on unidirectional encoding, leading to low semantic density and a mismatch between pre-training and downstream optimization. In this paper, we propose TimeMAE, a self-supervised framework that reformulates masked modeling for time series via semantic unit elevation and decoupled representation learning. Instead of modeling individual time steps, TimeMAE segments time series into non-overlapping sub-series to form semantically enriched units, enabling more informative masked reconstruction while reducing computational cost. To address the representation discrepancy introduced by masking, we design a decoupled masked autoencoder that separately encodes visible and masked regions, avoiding artificial masked tokens in the main encoder. To guide pre-training, we introduce two complementary objectives: masked codeword classification, which discretizes sub-series semantics via a learned tokenizer and masked representation regression, which aligns continuous representations through a momentum-updated target encoder. Extensive experiments on five datasets demonstrate that TimeMAE outperforms competitive baselines, particularly in label-scarce scenarios and transfer learning scenarios.
title TimeMAE: Self-Supervised Representations of Time Series with Decoupled Masked Autoencoders
topic Machine Learning
url https://arxiv.org/abs/2303.00320