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arXiv 1607.03592stat.COcs.NAmath.NAstat.AP
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非高斯数据同化中的聚类采样滤波器

Cluster Sampling Filters for Non-Gaussian Data Assimilation

Virginia Polytechnic Institute and State University(弗吉尼亚理工大学)

Ahmed Attia, Azam Moosavi, Adrian Sandu

AI总结:

本文提出一种非高斯Hamilton蒙特卡罗采样滤波器,通过引入聚类步骤和高斯混合模型估计先验密度,实现对非高斯先验的灵活处理,验证了该方法在准地转模型中的有效性。

摘要:

本文提出了一种完全非高斯版本的Hamilton蒙特卡罗(HMC)采样滤波器。在原始HMC滤波器中对高斯先验假设的放松是关键。具体而言,在滤波的预报阶段之后引入聚类步骤,并通过拟合高斯混合模型(GMM)到先验集合来估计先验密度函数。利用数据似然函数,后验密度被公式化为混合密度,并通过HMC方法(或其他能够高维子空间中采样多模态密度的方案)进行采样。本文开发的主要滤波器称为“聚类HMC采样滤波器”(ClHMC)。还提出了ClHMC的多链版本,即MC-ClHMC,以确保样本从后验概率模式的所有邻域中被采样。新方法在双涡旋风强迫和双谐波摩擦的准地转模型中进行了测试。数值结果展示了使用GMM放松HMC滤波范式中高斯先验假设的有用性。

英文摘要:

This paper presents a fully non-Gaussian version of the Hamiltonian Monte Carlo (HMC) sampling filter. The Gaussian prior assumption in the original HMC filter is relaxed. Specifically, a clustering step is introduced after the forecast phase of the filter, and the prior density function is estimated by fitting a Gaussian Mixture Model (GMM) to the prior ensemble. Using the data likelihood function, the posterior density is then formulated as a mixture density, and is sampled using a HMC approach (or any other scheme capable of sampling multimodal densities in high-dimensional subspaces). The main filter developed herein is named "cluster HMC sampling filter" (ClHMC). A multi-chain version of the ClHMC filter, namely MC-ClHMC is also proposed to guarantee that samples are taken from the vicinities of all probability modes of the formulated posterior. The new methodologies are tested using a quasi-geostrophic (QG) model with double-gyre wind forcing and bi-harmonic friction. Numerical results demonstrate the usefulness of using GMMs to relax the Gaussian prior assumption in the HMC filtering paradigm.

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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