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Full-Text Articles in Electrical and Computer Engineering
Theory And Applications Of Compressive Sensing, Atul Divekar, Okan Ersoy
Theory And Applications Of Compressive Sensing, Atul Divekar, Okan Ersoy
Department of Electrical and Computer Engineering Technical Reports
This thesis develops algorithms and applications for compressive sensing, a topic in signal processing that allows reconstruction of a signal from a limited number of linear combinations of the signal. New algorithms are described for common remote sensing problems including superresolution and fusion of images. The algorithms show superior results in comparison with conventional methods. We describe a method that uses compressive sensing to reduce the size of image databases used for content based image retrieval. The thesis also describes an improved estimator that enhances the performance of Matching Pursuit type algorithms, several variants of which have been developed for …
Throughput And Delay Analysis On Uncoded And Coded Wireless Broadcast With Hard Deadline Constraints, Xiaohang Li, Chih-Chun Wang, Xiaojun Lin
Throughput And Delay Analysis On Uncoded And Coded Wireless Broadcast With Hard Deadline Constraints, Xiaohang Li, Chih-Chun Wang, Xiaojun Lin
Department of Electrical and Computer Engineering Technical Reports
Multimedia streaming applications have stringent QoS requirements. Typically each packet is associated with a packet delivery deadline. This work models and considers realtime streaming broadcast over the downlink of a single cell. The broadcast capacity of the system subject to deadline constraints are studied for both uncoded and coded wireless broadcast schemes. For the uncoded scenario, an optimal transmission policy is devised based on finite-horizon dynamic programming, and a closed-form expression of the optimal throughput is developed in the asymptotic regime, as the size of the file approaches infinity. For the coded scenario, the optimal capacity in the asymptotic regime …
Probabilistic Matching Pursuit For Compressive Sensing, Atul Divekar, Okan K. Ersoy
Probabilistic Matching Pursuit For Compressive Sensing, Atul Divekar, Okan K. Ersoy
Department of Electrical and Computer Engineering Technical Reports
Compressive sensing investigates the recovery of a signal that can be sparsely represented in an orthonormal basis or overcomplete dictionary given a small number of linear combinations of the signal. We present a novel matching pursuit algorithm that uses the measurements to probabilistically select a subset of bases that is likely to contain the true bases constituting the signal. The algorithm is successful in recovering the original signal in cases where deterministic matching pursuit algorithms fail. We also show that exact recovery is possible when the number of nonzero coefficients is upto one less than the number of measurements. This …
H-Matrix-Based Fast Direct Finite Element Solver For Large-Scale Electromagnetic Analysis, Haixin Liu, Dan Jiao
H-Matrix-Based Fast Direct Finite Element Solver For Large-Scale Electromagnetic Analysis, Haixin Liu, Dan Jiao
Department of Electrical and Computer Engineering Technical Reports
In this work, we prove that the sparse matrix resulting from a finite-element-based analysis of electrodynamic problems can be represented by an H-matrix without any approximation, and the inverse of this sparse matrix has a data-sparse H-matrix approximation with error well controlled. Based on this proof, we develop an H-matrix-based direct finite-element solver of O(kNlogN) memory complexity and O(k2Nlog2N) time complexity for solving electromagnetic problems, where k is a small variable that is adaptively determined based on accuracy requirements, and N is the number of unknowns. Both inversebased and LU-based direct solutions are developed. The LU-based solution is further accelerated …
A Theoretically Rigorous Full-Wave Finite-Element-Based Solution Of Maxwell's Equations From Dc To High Frequencies, Jianfang Zhu, Dan Jiao
A Theoretically Rigorous Full-Wave Finite-Element-Based Solution Of Maxwell's Equations From Dc To High Frequencies, Jianfang Zhu, Dan Jiao
Department of Electrical and Computer Engineering Technical Reports
It has been observed that finite element based solutions of full-wave Maxwell's equations break down at low frequencies. In this paper, we present a theoretically rigorous method to fundamentally eliminate the low-frequency breakdown problem. The key idea of this method is that the original frequency-dependent deterministic problem can be rigorously solved from a generalized eigenvalue problem that is frequency independent. In addition, we found that the zero eigenvalues of the generalized eigenvalue problem cannot be obtained as zeros because of finite machine precision. We hence correct the inexact zero eigenvalues to be exact zeros. The validity and accuracy of the …