通过动态系统建模,让生理信号自监督学习更懂身体状态。
Self-Supervised Dynamical System Representations for Physiological Time-Series
- 基于多时序共享系统参数,分离可迁移的生理信息与个体噪声。
- 在合成数据上验证理论有效性,在真实数据中提升分类与迁移性能。
- 适合做生理信号表征学习、低标签场景下的医疗分析任务。
自监督学习在生理时序数据中的效果取决于预训练目标能否保留潜在生理状态信息并过滤无关噪声。现有方法受限于启发式设计或约束不足的生成任务。为此,我们提出一种利用多时序动态系统生成模型信息结构的预训练框架。关键洞察在于:类别信息可通过提取跨样本共享的系统参数相关变量来高效捕捉,而仅属于单个样本的噪声应被丢弃。基于此,我们提出PULSE,一种基于交叉重建的预训练目标,显式提取系统信息并摒弃非可迁移的样本特异性信息。我们建立了理论,给出系统信息可恢复的充分条件,并在合成动力系统实验中实证验证。进一步应用于多个真实世界数据集,结果表明,PULSE学习到的表示能有效区分语义类别,提升标签效率,并改善迁移学习表现。
原文摘要 · Abstract (English)
The effectiveness of self-supervised learning (SSL) for physiological time series depends on the ability of a pretraining objective to preserve information about the underlying physiological state while filtering out unrelated noise. However, existing strategies are limited due to reliance on heuristic principles or poorly constrained generative tasks. To address this limitation, we propose a pretraining framework that exploits the information structure of a dynamical systems generative model across multiple time-series. This framework reveals our key insight that class identity can be efficiently captured by extracting information about the generative variables related to the system parameters shared across similar time series samples, while noise unique to individual samples should be discarded. Building on this insight, we propose PULSE, a cross-reconstruction-based pretraining objective for physiological time series datasets that explicitly extracts system information while discarding non-transferrable sample-specific ones. We establish theory that provides sufficient conditions for the system information to be recovered, and empirically validate it using a synthetic dynamical systems experiment. Furthermore, we apply our method to diverse real-world datasets, demonstrating that PULSE learns representations that can broadly distinguish semantic classes, increase label efficiency, and improve transfer learning.
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