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A DistributedMemory Randomized Structured Multifrontal Method for Sparse Direct Solutions
(2017)We design a distributedmemory randomized structured multifrontal solver for large sparse matrices. Two layers of hierarchical tree parallelism are used. A sequence of innovative parallel methods are developed for randomized ... 
An alternating direction and projection algorithm for structureenforced matrix factorization
(2017)Structureenforced matrix factorization (SeMF) represents a large class of mathematical models appearing in various forms of principal component analysis, sparse coding, dictionary learning and other machine learning ... 
Angola Cameia Development CasingSettlement Calculations
(2017)The amount of axial settlement of casings supported by regions of axial elastic foundations is computed. The differential equation of axial equilibrium, including the foundation stiffnesses, is solved by use of cubic axial ... 
Fullwaveform inversion via sourcereceiver extension
(2017)Fullwaveform inversion produces highly resolved images of the subsurface and quantitative estimation of seismic wave velocity, provided that its initial model is kinematically accurate at the longest data wavelengths. If ... 
Shape Optimization of Shell Structure Acoustics
(2017)This paper provides a rigorous framework for the numerical solution of shape optimization problems in shell structure acoustics using a referencedomain approach. The structure is modeled with Naghdi shell equations, fully ... 
A Branch Decomposition Algorithm for the pMedian Problem
(2017)In this paper, we use a branch decomposition technique to improve approximations to the pmedian problem. Starting from a support graph produced either by a combination of heuristics or by linear programming, we use dynamic ... 
ResidualBased Adaptivity and PWDG Methods for the Helmholtz Equation
(2015)We present a study of two residual a posteriori error indicators for the plane wave discontinuous Galerkin (PWDG) method for the Helmholtz equation. In particular, we study the $h$version of PWDG in which the number of ... 
A Comparison of High Order Interpolation Nodes for the Pyramid
(2015)The use of pyramid elements is crucial to the construction of efficient hexdominant meshes [M. Bergot, G. Cohen, and M. Duruflé, J. Sci. Comput., 42 (2010), pp. 345381]. For conforming nodal finite element methods with ... 
An Efficient GaussNewton Algorithm for Symmetric LowRank Product Matrix Approximations
(2015)We derive and study a GaussNewton method for computing a symmetric lowrank product $XX^{{T}}$, where $X \in{\mathbb{R}}^{n\times k}$ for $k<n$, that is the closest to a given symmetric matrix $A \in{\mathbb{R}}^{n\times ... 
Optimal Convergence Rates Results for Linear Inverse Problems in Hilbert Spaces
(2016)In this article, we prove optimal convergence rates results for regularization methods for solving linear illposed operator equations in Hilbert spaces. The results generalizes existing convergence rates results on ... 
A DEIM Induced CUR Factorization
(2016)We derive a CUR approximate matrix factorization based on the discrete empirical interpolation method (DEIM). For a given matrix ${\bf A}$, such a factorization provides a lowrank approximate decomposition of the form ... 
Inverse Boundary Value Problem For The Helmholtz Equation: Quantitative Conditional Lipschitz Stability Estimates
(2016)We study the inverse boundary value problem for the Helmholtz equation using the DirichlettoNeumann map at selected frequencies as the data. A conditional Lipschitz stability estimate for the inverse problem holds in the ... 
An approximate inverse to the extended Born modeling operator
(2015)Given a correct (dataconsistent) velocity model, reverse time migration (RTM) correctly positions reflectors but generally with incorrect amplitudes and wavelets. Iterative leastsquares migration (LSM) corrects the ... 
Numerical method of characteristics for onedimensional blood flow
(2015)Mathematical modeling at the level of the full cardiovascular system requires the numerical approximation of solutions to a onedimensional nonlinear hyperbolic system describing flow in a single vessel. This model is often ... 
Scattering and dip angle decomposition based on subsurface offset extended waveequation migration
(2016)An angledependent reflection coefficient is recovered by seismic migration in the angle domain. We have developed a postmigration technique for computing scattering and dip angle commonimage gathers (CIGs) from seismic ... 
An adaptive multiscale algorithm for efficient extended waveform inversion
(2017)Subsurfaceoffset extended fullwaveform inversion (FWI) may converge to kinematically accurate velocity models without the lowfrequency data accuracy required for standard datadomain FWI. However, this robust alternative ... 
Reconstruction of Lamé Moduli and Density at the Boundary Enabling Directional Elastic Wavefield Decomposition
(2017)We consider the inverse boundary value problem for the system of equations describing elastic waves in isotropic media on a bounded domain in $\mathbb{R}^3$ via a finitetime Laplace transform. The data are the dynamical ... 
Predicting solvation free energies and thermodynamics in polar solvents and mixtures using a solvationlayer interface condition
(2017)We demonstrate that with two small modifications, the popular dielectric continuum model is capable of predicting, with high accuracy, ion solvation thermodynamics (Gibbs free energies, entropies, and heat capacities) in ... 
Modulation of Orthographic Decoding by Frontal Cortex
(2016)Opinions are divided on whether word reading processes occur in a hierarchical, feedforward fashion or within an interactive framework. To critically evaluate these competing theories, we recorded electrocorticographic ... 
A Topological Model of the Hippocampal Cell Assembly Network
(2016)It is widely accepted that the hippocampal place cells' spiking activity produces a cognitive map of space. However, many details of this representation's physiological mechanism remain unknown. For example, it is believed ...