arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1909.06359math.STstat.MEstat.TH
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高维向量自回归过程的局部变化

Localizing Changes in High-Dimensional Vector Autoregressive Processes

Daren Wang, Yi Yu, Alessandro Rinaldo, Rebecca Willett

摘要:

自回归模型捕捉随机过程,其中过去的实现决定了新数据的生成分布;它们在各种工业,生物医学和金融环境中自然出现。处理这些数据时的一个关键挑战是确定底层生成模型何时发生变化,因为这可以提供对底层系统不同操作机制的见解。本文描述了一种新的动态规划方法,用于定位高维自回归过程中的变化和相关的差错率,改进了现有技术。当模型参数随时间分段恒定且相应的过程分段稳定时,所提出的动态规划算法即使在维数、系数矩阵的稀疏性允许两个连续变化点之间的时间间隔以及两个连续系数矩阵的差的幅度随样本量而变化。此外,可以经由可证明地改善定位差错率的计算高效的细化算法来提高初始粗略变化点定位估计的准确性。最后,通过仿真实验和实际数据分析,验证了本文方法的数值优越性。

英文摘要:

Autoregressive models capture stochastic processes in which past realizations determine the generative distribution of new data; they arise naturally in a variety of industrial, biomedical, and financial settings. A key challenge when working with such data is to determine when the underlying generative model has changed, as this can offer insights into distinct operating regimes of the underlying system. This paper describes a novel dynamic programming approach to localizing changes in high-dimensional autoregressive processes and associated error rates that improve upon the prior state of the art. When the model parameters are piecewise constant over time and the corresponding process is piecewise stable, the proposed dynamic programming algorithm consistently localizes change points even as the dimensionality, the sparsity of the coefficient matrices, the temporal spacing between two consecutive change points, and the magnitude of the difference of two consecutive coefficient matrices are allowed to vary with the sample size. Furthermore, the accuracy of initial, coarse change point localization estimates can be boosted via a computationally-efficient refinement algorithm that provably improves the localization error rate. Finally, a comprehensive simulation experiments and a real data analysis are provided to show the numerical superiority of our proposed methods.

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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