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arXiv 1507.05073stat.COstat.ML
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基于Hermite级数的序贯分位数密度估计

Sequential Quantiles via Hermite Series Density Estimation

Michael Stephanou, Melvin Varughese, Iain Macdonald

摘要:

序贯分位数估计是指以增量方式将观测值合并到分位数估计值中,从而在任何给定时间点提供一个或多个分位数的在线估计值。序贯分位数估计也称为在线分位数估计。这个领域与数据流分析和大规模数据集的一次性分析有关。应用包括网络流量和延迟分析、实时欺诈检测和高频交易。在静态分位数估计和动态分位数估计的背景下,提出了基于Hermite级数估计的在线分位数估计新方法。在静态分位数估计设置中,我们以一种新的方式应用现有的Gauss-Hermite展开。特别是,我们利用高斯-厄米系数可以按顺序更新的事实。为了处理动态分位数估计,我们引入了一种新的扩展与指数加权估计的高斯-厄米特系数,我们称之为指数加权高斯-厄米特(EWGH)的扩展。这些算法超越了现有的顺序分位数估计算法,因为它们允许在任何时间点估计任意分位数(与预先指定的分位数相反)。在这样做,我们提供了一个解决方案,在线分布函数和在线分位数函数估计的数据流。特别是,我们推导出的CDF的解析表达式,并证明在一定条件下的CDF的一致性结果。此外,我们分析了相关的分位数估计。仿真研究和实际数据的测试表明,基于高斯-厄米特算法是具有竞争力的领先的现有算法。

英文摘要:

Sequential quantile estimation refers to incorporating observations into quantile estimates in an incremental fashion thus furnishing an online estimate of one or more quantiles at any given point in time. Sequential quantile estimation is also known as online quantile estimation. This area is relevant to the analysis of data streams and to the one-pass analysis of massive data sets. Applications include network traffic and latency analysis, real time fraud detection and high frequency trading. We introduce new techniques for online quantile estimation based on Hermite series estimators in the settings of static quantile estimation and dynamic quantile estimation. In the static quantile estimation setting we apply the existing Gauss-Hermite expansion in a novel manner. In particular, we exploit the fact that Gauss-Hermite coefficients can be updated in a sequential manner. To treat dynamic quantile estimation we introduce a novel expansion with an exponentially weighted estimator for the Gauss-Hermite coefficients which we term the Exponentially Weighted Gauss-Hermite (EWGH) expansion. These algorithms go beyond existing sequential quantile estimation algorithms in that they allow arbitrary quantiles (as opposed to pre-specified quantiles) to be estimated at any point in time. In doing so we provide a solution to online distribution function and online quantile function estimation on data streams. In particular we derive an analytical expression for the CDF and prove consistency results for the CDF under certain conditions. In addition we analyse the associated quantile estimator. Simulation studies and tests on real data reveal the Gauss-Hermite based algorithms to be competitive with a leading existing algorithm.

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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