论文标题
数据驱动的多项式混沌扩展的稀疏近似:诱导采样方法
Sparse approximation of data-driven Polynomial Chaos expansions: an induced sampling approach
论文作者
论文摘要
正向不确定性量化(UQ)领域中的一个开放问题之一是能够对仅有关随机输入分布的不完整信息进行准确评估不确定性的能力。另一个挑战是有效利用有限的培训数据来用于对复杂工程问题的UQ预测,尤其是在高维随机参数的情况下。我们通过将数据驱动的多项式混乱扩展与最近开发的UQ问题预处理的稀疏近似方法相结合,以解决这些挑战。这两个步骤过程中的第一个任务是采用(Ahlfeld等人,2016年)中开发的过程,以使用随机输入的有限数量的统计矩构建“任意”的多项式混沌扩展基础。第二步是通过$ \ ell^1 $最小化实现稀疏近似的新过程,以量化正向不确定性。为了增强预处理的$ \ ell^1 $最小化问题的性能,我们从所谓的诱导分布中采样,而不是使用原始未知概率度量的蒙特卡洛(MC)采样。我们在测试问题上证明,与来自渐近最佳措施(例如平衡度量)的采样相比,引起采样是一种竞争性,通常是更好的选择。我们通过稀疏表示,在测试函数的数据和Kirchoff Plending弯曲问题上通过Random Young的模量进行了有限的数据,证明了提出的诱导采样算法的能力。
One of the open problems in the field of forward uncertainty quantification (UQ) is the ability to form accurate assessments of uncertainty having only incomplete information about the distribution of random inputs. Another challenge is to efficiently make use of limited training data for UQ predictions of complex engineering problems, particularly with high dimensional random parameters. We address these challenges by combining data-driven polynomial chaos expansions with a recently developed preconditioned sparse approximation approach for UQ problems. The first task in this two-step process is to employ the procedure developed in (Ahlfeld et al. 2016) to construct an "arbitrary" polynomial chaos expansion basis using a finite number of statistical moments of the random inputs. The second step is a novel procedure to effect sparse approximation via $\ell^1$ minimization in order to quantify the forward uncertainty. To enhance the performance of the preconditioned $\ell^1$ minimization problem, we sample from the so-called induced distribution, instead of using Monte Carlo (MC) sampling from the original, unknown probability measure. We demonstrate on test problems that induced sampling is a competitive and often better choice compared with sampling from asymptotically optimal measures (such as the equilibrium measure) when we have incomplete information about the distribution. We demonstrate the capacity of the proposed induced sampling algorithm via sparse representation with limited data on test functions, and on a Kirchoff plating bending problem with random Young's modulus.