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arXiv 2305.10656stat.ME
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基于稀疏张量分解的高维时间序列谱变点估计

Spectral Change Point Estimation for High Dimensional Time Series by Sparse Tensor Decomposition

East China Normal University(华东师范大学)

Xinyu Zhang, Kung-Sik Chan

AI总结:

该研究针对高维时间序列,提出基于稀疏张量分解的频域变点检测方法,经理论保证和仿真、股票收益应用验证,可定位变点并识别对应激活序列与频率。

摘要:

多变量时间序列可能在特定频带上发生局部结构变化,例如在神经科学领域。我们在频域框架内研究高维时间序列的变点检测问题,总体目标是定位所有变点,并明确哪些序列会因变点激活、以及在哪些频率上激活。实际中,每个变点对应的激活序列数量和频率范围可从少数到全部参与不等。我们的解决方法是:首先基于时间序列块估计的谱计算CUSUM张量,应用频域特定的投影方法进行降维,投影方向由所提出的、可调整变点稀疏度水平的张量分解算法估计;最后聚合跨频率的投影CUSUM向量以进行变点检测。我们为估计的变点数量及其位置的收敛速率提供理论保证,推导了用于识别变点中频域特定激活序列的估计投影方向的误差界,还提供了数据驱动的参数选择规则。仿真和股票收益应用验证了所提方法的有效性。

英文摘要:

Multivariate time series may be subject to partial structural changes over certain frequency band, for instance, in neuroscience. We study the change point detection problem with high dimensional time series, within the framework of frequency domain. The overarching goal is to locate all change points and delineate which series are activated by the change, over which frequencies. In practice, the number of activated series per change and frequency could span from a few to full participation. We solve the problem by first computing a CUSUM tensor based on spectra estimated from blocks of the time series. A frequency-specific projection approach is applied for dimension reduction. The projection direction is estimated by a proposed tensor decomposition algorithm that adjusts to the sparsity level of changes. Finally, the projected CUSUM vectors across frequencies are aggregated for change point detection. We provide theoretical guarantees on the number of estimated change points and the convergence rate of their locations. We derive error bounds for the estimated projection direction for identifying the frequency-specific series activated in a change. We provide data-driven rules for the choice of parameters. The efficacy of the proposed method is illustrated by simulation and a stock returns application.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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