论文标题

更高阶的无声转换

A Higher Order Unscented Transform

论文作者

Easley, Deanna, Berry, Tyrus

论文摘要

我们开发了一种新方法,用于估计应用于具有任意分布的多元随机变量的非线性函数的预期值。我们没有假设我们只给出分布的前四个时刻,而是假设我们只有。目的是使用少量的正交节点总结分布,这些节点称为$σ$ - 点。我们通过选择节点和权重来实现这一目标,以匹配分布的指定矩。经典缩放的无气味变换(SUT)与分布的平均值和协方差相匹配。在本文中,引入了高阶的无气体变换(Hout),该变换也与任何给定的偏度和峰度张量相匹配。事实证明,匹配较高时刻的关键是等级-1张量分解。虽然最小的等级-1分解是NP完整的,但我们提出了一种用于计算非最低级别秩-1分解并在线性时间中证明收敛性的实用算法。然后,我们展示如何结合矩的排名1分解,以形成$σ$ - 点和权重。通过非线性函数传递$σ$ - 点并应用我们的正交规则,我们可以估计输出分布的矩。我们证明,任意多项式最高第四阶的任意多项式。最后,我们从数值上比较了应用于非高斯随机变量的非线性函数的SUT,包括用于预测和不确定性定量混乱动力学的应用。

We develop a new approach for estimating the expected values of nonlinear functions applied to multivariate random variables with arbitrary distributions. Rather than assuming a particular distribution, we assume that we are only given the first four moments of the distribution. The goal is to summarize the distribution using a small number of quadrature nodes which are called $σ$-points. We achieve this by choosing nodes and weights in order to match the specified moments of the distribution. The classical scaled unscented transform (SUT) matches the mean and covariance of a distribution. In this paper, introduce the higher order unscented transform (HOUT) which also matches any given skewness and kurtosis tensors. It turns out that the key to matching the higher moments is the rank-1 tensor decomposition. While the minimal rank-1 decomposition is NP-complete, we present a practical algorithm for computing a non-minimal rank-1 decomposition and prove convergence in linear time. We then show how to combine the rank-1 decompositions of the moments in order to form the $σ$-points and weights of the HOUT. By passing the $σ$-points through a nonlinear function and applying our quadrature rule we can estimate the moments of the output distribution. We prove that the HOUT is exact on arbitrary polynomials up to fourth order. Finally, we numerically compare the HOUT to the SUT on nonlinear functions applied to non-Gaussian random variables including an application to forecasting and uncertainty quantification for chaotic dynamics.

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