arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 1907.09477math.STstat.MEstat.TH
收藏

多元时间序列极值的多块大小和重叠块

Multiple block sizes and overlapping blocks for multivariate time series extremes

Nan Zou, Stanislav Volgushev, Axel Bücher

摘要:

块极大值方法构成了极值分析中统计工具箱的基本部分。然而,大多数相应的理论是在简化的假设下得出的,即块极大值是来自真正的极值分布的独立观测值。然而,在实践中,块大小是有限的,并且来自不同块的观测是相关的。关于后者的并发症的理论还没有得到很好的发展,并且在多变量的情况下,最近才建立了一个单一的块大小的不相交块。我们表明,使用重叠的块,而不是不相交的块导致统一的改进的渐进方差的多变量经验分布函数的重新缩放块的最大值和任何光滑的泛函(如经验copula),而没有任何牺牲的渐近偏差。我们进一步推导出多元经验分布函数和经验copula函数的泛函中心极限定理,这些函数在块大小参数上是一致的,这似乎是基于块极大值的估计的第一个结果。该理论允许在多个块大小上的各种聚合方案,导致在单个分组长度情况下的实质性改进,并为进一步的方法开发打开了大门。特别是,我们考虑偏差校正程序,可以提高极值估计的收敛速度,并在主要目的是偏差校正时,对二阶参数的估计提供一些新的启示。

英文摘要:

Block maxima methods constitute a fundamental part of the statistical toolbox in extreme value analysis. However, most of the corresponding theory is derived under the simplifying assumption that block maxima are independent observations from a genuine extreme value distribution. In practice however, block sizes are finite and observations from different blocks are dependent. Theory respecting the latter complications is not well developed, and, in the multivariate case, has only recently been established for disjoint blocks of a single block size. We show that using overlapping blocks instead of disjoint blocks leads to a uniform improvement in the asymptotic variance of the multivariate empirical distribution function of rescaled block maxima and any smooth functionals thereof (such as the empirical copula), without any sacrifice in the asymptotic bias. We further derive functional central limit theorems for multivariate empirical distribution functions and empirical copulas that are uniform in the block size parameter, which seems to be the first result of this kind for estimators based on block maxima in general. The theory allows for various aggregation schemes over multiple block sizes, leading to substantial improvements over the single block length case and opens the door to further methodology developments. In particular, we consider bias correction procedures that can improve the convergence rates of extreme-value estimators and shed some new light on estimation of the second-order parameter when the main purpose is bias correction.

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。

↑