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Numerical Methods for Optimal Experimental Design of Ill-posed Problems.

机译:不适定问题最优实验设计的数值方法。

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摘要

The two goals of this thesis are to develop numerical methods for solving large-scale optimal experimental design problems efficiently and to apply optimal experimental design ideas to applications in regularization techniques and geophysics.;The thesis can be divided into three parts. In the first part, we consider the problem of experimental design for linear ill-posed inverse problems. The minimization of the objective function in the classic A-optimal design is generalized to a Bayes risk minimization with a sparsity constraint. We present efficient algorithms for applications of such designs to large-scale problems. This is done by employing Krylov subspace methods for the solution of a subproblem required to obtain the experiment weights. The performance of the designs and algorithms is illustrated with a one-dimensional magnetotelluric example and an application to two-dimensional super-resolution reconstruction with MRI data.;In the second part, we find the optimal regularization for linear ill-posed problems. We propose an optimal ℓ2 regularization approach enabling us to obtain inexpensive and good solutions to the inverse problem. In order to reduce the computational cost, several sparsity patterns are added to the regularization operator. Numerical experiments will show that our optimal ℓ 2 regularization approach provides much better results than the traditional Tikhonov regularization.;In the last part of the thesis, we design optimal placement of sources and receivers in a CO2 injection monitoring. An optimal criteria is proposed based on a target zone and different treatments for placing sources and receivers are discussed.
机译:本文的两个目标是开发有效解决大规模最优实验设计问题的数值方法,并将最优实验设计思想应用于正则化技术和地球物理学中。;论文可分为三个部分。在第一部分中,我们考虑线性不适定反问题的实验设计问题。经典A最优设计中目标函数的最小化被推广为具有稀疏约束的贝叶斯风险最小化。我们提出了将此类设计应用于大规模问题的有效算法。这是通过使用Krylov子空间方法来解决获得实验权重所需的子问题的。通过一维大地电磁实例说明了该设计和算法的性能,并将其应用到利用MRI数据进行二维超分辨率重建中。第二部分,我们找到了线性不适定问题的最佳正则化方法。我们提出了一种最佳的ℓ 2正则化方法,使我们能够获得反问题的廉价且良好的解决方案。为了减少计算成本,将几种稀疏模式添加到正则化运算符。数值实验表明,我们的最优ℓ 2正则化方法比传统的Tikhonov正则化方法要好得多。在本文的最后一部分,我们设计了在CO2注入监测中优化源和接收器的位置。根据目标区域提出了最佳标准,并讨论了放置源和接收器的不同方法。

著录项

  • 作者

    Magnant, Zhuojun.;

  • 作者单位

    Emory University.;

  • 授予单位 Emory University.;
  • 学科 Education Mathematics.;Applied Mathematics.;Education Sciences.
  • 学位 Ph.D.
  • 年度 2011
  • 页码 150 p.
  • 总页数 150
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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