arXiv:2409.09930cs.LG2024-09KDD被引 10

用动态稀疏网络捕捉变量关系,实现多变量时间序列缺失值精准填补。

Mining of Switching Sparse Networks for Missing Value Imputation in Multivariate Time Series

论文配图:Mining of Switching Sparse Networks for Missing Value Imputation in Multivariate Time Series
图 1 · 摘自论文原文
  • 基于状态空间模型与可切换稀疏网络,联合建模时间依赖与变量间关系。
  • 在多个真实数据集上优于现有方法,均方误差降低10%以上。
  • 可自动发现网络结构变化点,结果可解释,适合需要透明性的场景。

多变量时间序列常存在缺失值问题,阻碍了诸多分析方法的应用。为实现高精度填补,除了利用时间依赖性外,挖掘序列间的相关性(即构建网络)同样关键,且网络结构会随时间动态变化。然而在实际中,我们通常无法预先知道网络结构或其变化时机。为此,本文提出一种名为 MissNet 的缺失值填补方法,通过状态空间模型捕捉时间依赖,并借助可切换稀疏网络建模变量间关联。该网络编码特征间的条件独立性,有助于直观理解关键关系。算法在保持线性时间复杂度的前提下,交替推断网络结构并填补缺失值,同时识别网络切换点。大量实验表明,MissNet 在多项主流指标上超越现有最佳方法,且提供可解释的结果。

原文摘要 · Abstract (English)

Multivariate time series data suffer from the problem of missing values, which hinders the application of many analytical methods. To achieve the accurate imputation of these missing values, exploiting inter-correlation by employing the relationships between sequences (i.e., a network) is as important as the use of temporal dependency, since a sequence normally correlates with other sequences. Moreover, exploiting an adequate network depending on time is also necessary since the network varies over time. However, in real-world scenarios, we normally know neither the network structure nor when the network changes beforehand. Here, we propose a missing value imputation method for multivariate time series, namely MissNet, that is designed to exploit temporal dependency with a state-space model and inter-correlation by switching sparse networks. The network encodes conditional independence between features, which helps us understand the important relationships for imputation visually. Our algorithm, which scales linearly with reference to the length of the data, alternatively infers networks and fills in missing values using the networks while discovering the switching of the networks. Extensive experiments demonstrate that MissNet outperforms the state-of-the-art algorithms for multivariate time series imputation and provides interpretable results.

时间序列缺失值填补稀疏网络可解释性

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