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A New Alternating Minimization Algorithm for Total Variation Image Reconstruction
(2007-06)
We propose, analyze and test an alternating minimization algorithm for recovering images from blurry and noisy observa- tions with total variation (TV) regularization. This algorithm arises from a new half-quadratic model ...
Domain Decomposition and Model Reduction of Systems with Local Nonlinearities
(2007-11)
The goal of this paper is to combine balanced truncation model reduction and domain decomposition to derive reduced order models with guaranteed error bounds for systems of discretized partial differential equations (PDEs) ...
Passivity Preserving Model Reduction via Interpolation of Spectral Zeros: Selection Criteria and Implementation
(2007-09)
This thesis presents spectral zero selection criteria for a rigorous theory on passivity preserving model reduction via interpolation of spectral zeros. For linear time invariant systems in circuit simulation, passivity ...
A Fixed-Point Continuation Method for L_1-Regularization with Application to Compressed Sensing
(2007-05)
We consider solving minimization problems with L_1-regularization: min ||x||_1 + mu f(x) particularly for f(x) = (1/2)||Ax-b||M2, where A is m by n and m < n. Our goal is to construct efficient and robust algorithms for ...
A Study on Conditions for Sparse Solution Recovery in Compressive Sensing
(2007-08)
It is well-known by now that under suitable conditions L1 minimization can recover sparse solutions to under-determined linear systems of equations. More precisely, by solving the convex optimization problem min{||x||1 : ...
A MADS Algorithm with a Progressive Barrier for Derivative-Free Nonlinear Programming
(2007-12)
We propose a new algorithm for general constrained derivative-free optimization. As in most methods, constraint violations are aggregated into a single constraint violation function. As in filter methods, a threshold, or ...
Comparing Problem Formulation for Coupled Sets of Component
(2007-11)
In this paper several formulations and comparative test results are presented for problems involving the general paradigm of coupled sets of components. This paradigm is general enough to include systems of systems (SoS) ...
Migration Velocity Analysis and Waveform Inversion
(2007-03)
Waveform (output least squares) inversion of seismic reflection data can reconstruct remarkably detailed models of subsurface structure, and take into account essentially any physics of seismic wave propagation that can ...
Efficient and Accurate Simulation of Integrate-and-Fire Neuronal Networks in the Hippocampus
(2007-12)
This thesis evaluates a method of computing highly accurate solutions for network simulations of integrate-and-fire (IAF) neurons. Simulations are typically evolved using time-stepping, but since the IAF model is composed ...
Best Symmetric Low Rank Approximation Via the Symmetry Preserving Singular Value Decomposition
(2007-12)
The symmetry preserving singular value decomposition (SPSVD) produces the best symmetric (low rank) approximation to a set of data. These symmetric approximations are characterized via an invariance under the action of a ...