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arXiv 1702.01236math.NAcs.NAstat.ME
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改进的概率主成分分析用于降阶建模应用

Improved Probabilistic Principal Component Analysis for Application to Reduced Order Modeling

Clarkson University(克拉克森大学);National Security Technologies LLC(国家安全技术有限责任公司)

Indika Udagedara, Brian Helenbrook, Aaron Luttman, Jared Catenacci

AI总结:

本文改进概率主成分分析用于降阶建模,通过估计训练数据中的噪声并优化基向量,提高在噪声数据下的预测准确性。

摘要:

在先前的工作中,为随机系统构建了降阶模型(ROM),其中噪声数据被投影到主成分分析(PCA)导出的基向量上以获得无噪声数据的准确重建。该工作使用了为确定性数据设计的技术,PCA用于生成基函数,$L_2$投影用于创建重建。在本工作中,采用了概率方法。概率主成分分析(PPCA)用于生成基向量,从而允许估计训练数据中的噪声。PPCA还被改进,使得导出的基向量是正交的,并且可以估计训练数据集上基展开系数的方差。标准方法假设这些系数具有单位方差。基于PPCA的结果,应用模型选择标准来自动选择ROM的维度。在先前的工作中,使用启发式方法来选择维度。最后,使用新的统计方法进行投影步骤,其中从改进的PPCA获得的方差信息用作先验以改进投影。这在投影数据存在噪声时比$L_2$投影提供了更高的准确性。此外,投影数据的噪声统计不假设与训练数据相同,而是在投影过程中进行估计。整个方法提供了一种完全随机的方法,用于从噪声训练数据中计算ROM,确定理想的模型选择,并投影噪声测试数据,从而能够从数据中准确预测无噪声数据。

英文摘要:

In our previous work, a reduced order model (ROM) for a stochastic system was made, where noisy data was projected onto principal component analysis (PCA)-derived basis vectors to obtain an accurate reconstruction of the noise-free data. That work used techniques designed for deterministic data, PCA was used for the basis function generation and $L_2$ projection was used to create the reconstructions. In this work, probabilistic approaches are used. The probabilistic PCA (PPCA) is used to generate the basis, which then allows the noise in the training data to be estimated. PPCA has also been improved so that the derived basis vectors are orthonormal and the variance of the basis expansion coefficients over the training data set can be estimated. The standard approach assumes a unit variance for these coefficients. Based on the results of the PPCA, model selection criteria are applied to automatically choose the dimension of the ROM. In our previous work, a heuristic approach was used to pick the dimension. Lastly, a new statistical approach is used for the projection step where the variance information obtained from the improved PPCA is used as a prior to improve the projection. This gives improved accuracy over $L_2$ projection when the projected data is noisy. In addition, the noise statistics for the projected data are not assumed to be the same as that of the training data, but are estimated in the projection process. The entire approach gives a fully stochastic method for computing a ROM from noisy training data, determining ideal model selection, and projecting noisy test data, thus enabling accurate predictions of noise-free data from data that is dominated by noise.

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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