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arXiv 2006.12640stat.ME
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密度时间序列的Wasserstein自回归模型

Wasserstein Autoregressive Models for Density Time Series

Chao Zhang, Piotr Kokoszka, Alexander Petersen

摘要:

由时间指数分布的横截面或日内收益组成的数据在金融领域已经得到了广泛的研究,并提供了一个例子,其中数据原子由连续相关的概率分布组成。受这些数据的启发,我们提出了一个自回归模型的密度时间序列,利用切空间结构的分布空间,这是由Wasserstein度量。密度本身不被假设为具有任何特定的参数形式,从而可以灵活地预测未来未观测到的密度。阶$p$ Wasserstein自回归模型的主要估计指标是Wasserstein自相关和向量值自回归参数。我们提出了合适的估计,并建立其渐近正态性,这是在模拟研究中验证。新的顺序- $p$ Wasserstein自回归模型导致的预测算法,其中包括一个数据驱动的顺序选择过程。它的性能相比,现有的预测程序,通过应用程序的四个财务回报数据集,其中各种指标被用来量化预测的准确性。对于大多数指标,所提出的模型优于现有的方法在两个数据集,而最好的经验表现在其他两个数据集是通过现有的方法的基础上的密度的函数变换。

英文摘要:

Data consisting of time-indexed distributions of cross-sectional or intraday returns have been extensively studied in finance, and provide one example in which the data atoms consist of serially dependent probability distributions. Motivated by such data, we propose an autoregressive model for density time series by exploiting the tangent space structure on the space of distributions that is induced by the Wasserstein metric. The densities themselves are not assumed to have any specific parametric form, leading to flexible forecasting of future unobserved densities. The main estimation targets in the order-$p$ Wasserstein autoregressive model are Wasserstein autocorrelations and the vector-valued autoregressive parameter. We propose suitable estimators and establish their asymptotic normality, which is verified in a simulation study. The new order-$p$ Wasserstein autoregressive model leads to a prediction algorithm, which includes a data driven order selection procedure. Its performance is compared to existing prediction procedures via application to four financial return data sets, where a variety of metrics are used to quantify forecasting accuracy. For most metrics, the proposed model outperforms existing methods in two of the data sets, while the best empirical performance in the other two data sets is attained by existing methods based on functional transformations of the densities.

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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