Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"Conjugate Gradient Algorithm"”.
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A "HUM" conjugate gradient algorithm for constrained nonlinear optimal control : terminal and regular problems
… constraints on the control variables. The algorithm has been developed so that systems governed by general parabolic partial differential equations can be solved. The problems addressed are of the regulator-terminal type, in which deviations from specified state variable behavior are …
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An updating rule for the penalty constant used in the penalty function method for mathematical programming problems
… be increased when shifting from one cycle of the algorithm to the next. Here, k denotes the penalty constant of the present cycle, and k* denotes the penalty constant of the next cycle. In this dissertation, two updating rules are compared: (a) the penalty constant is increased at a constant rate …
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GPU-accelerated Linear Solvers for High-order Finite Element Methods in Poisson Problems
… develops and analyzes numerical methods and algorithms aimed at improving the convergence and efficiency of the preconditioned conjugate gradient (PCG) algorithm for high-order finite element methods on Graphics Processing Units (GPUs). The conjugate gradient algorithm iteratively refines an …
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Preconditioned sequential and parallel conjugate gradient algorithms for homotopy curve tracking
There are algorithms for finding zeros or fixed points of nonlinear systems of equations that are globally convergent for almost all starting points, i.e., with probability one. The essence of all such algorithms is the construction of an appropriate homotopy map and then tracking some smooth curve …
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Fast Algorithms for Volterra-Series-Based Nonlinear Adaptive Filters
Two efficient algorithms for the second-order adaptive Volterra filter are developed in Chapter 2. By utilizing the special structure of the input correlation matrix of the Volterra filter the two algorithms essentially implement quasi-Newton algorithm with $O\lbrack {\rm N}\sp2\rbrack$ …
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Krylov subspace estimation
This thesis proposes a new iterative algorithm for the simultaneous computation of linear least-squares estimates and error variances. There exist many iterative methods for computing only estimates. However, most of these will not also compute error variances. A popular method for computing only …
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Preconditioned iterative methods on virtual shared memory machines
… Schatz. The Krylov subspace method used was the conjugate gradient algorithm. The linear systems being solved are derived from finite difference discretization of elliptic boundary value problems. Most of the focus of this thesis is upon how data structures affect performance of the algorithm on …
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Novel Monte Carlo Methods for Large-Scale Linear Algebra Operations
… deterministic numerical linear algebra algorithms have difficulty to scale to handle large data sets.</p> <p>Monte Carlo methods, which are based on statistical sampling, exhibit many attractive properties in dealing with large volume of datasets, including fast approximated results, …
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Comparison of energy minimization with direct stiffness for linear structural analysis
… analyzed. From the survey of variable metric and conjugate gradient algorithms included in this study, the Davidon-Fletcher-Powell variable metric algorithm and the FletcherReeves conjugate gradient algorithm were chosen to minimize the total potential energy. A description of both algorithms is …
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Support Vector Machine algorithms : analysis and applications
… of my thesis work is to improve computational algorithms as well as the mathematical understanding of SVMs, so that they can be easily applied to real problems. SVMs solve classification problems by learning from training examples. From the geometry, it is easy to formulate the finding of SVM …
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Computer modelling of plastic deformation and fracture in heterogeneous systems.
… linearity and is, therefore, solvable using a conjugate gradient algorithm. Fracture is introduced through the iterative removal of bonds, where clusters of bonds normal to a potential fracture plane are considered. The model gives reasonable agreement with theoretical predictions for the …
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High fidelity imaging in electrical impedance tomography
… We extend the developed iterative Newton-Raphson algorithm to include image smoothness constraints and adaptive mesh refinement based on conductivity gradients in the image. The results show that the image resolution can be made independent of the underlying numerical discretization and therefore …
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A Method for Characterizing the Properties of Industrial Foams
… asymmetry parameter varied between 0 and 1. A conjugate-gradient algorithm was used to minimize the difference between simulated Monte Carlo measurements and diffusion theory predicted measurements. A large set of simulated measurements, calculated at various source-detector separations and …
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Iterative Techniques for Radial Basis Function Interpolation
… techniques. They were developed from an algorithm described by Beatson, Goodsell and Powell (1995), which is examined first. By gaining more and more theoretical insight into the original algorithm, new algorithms are developed and connections to known methods are made. We establish the …
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Reconstruction of the Temperature Profile Along a Blackbody Optical Fiber Thermometer
<p>A blackbody optical fiber thermometer consists of an optical fiber whose sensing tip is given a metallic coating. The sensing tip of the fiber forms an isothermal cavity, and the emission from this cavity is approximately equal to the emission from a blackbody. Standard two-color optical fiber …
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Optimisation Methods For Training Deep Neural Networks in Speech Recognition
… learning difficult via first order stochastic gradient descent (SGD). The task of finding the best procedure to train DNNs continues to be an active area of research and has been made even more challenging by the availability of ever more training data. This thesis focuses on designing better …
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Solution of a Second Order Elliptic Partial Differential Equation with Varying Complex Coefficients: An Application for Computing Effective Complex Electrical Properties of Materials represented by 3D Images
… an energy function which is minimised using the Conjugate Gradient algorithm. It allows to obtain the electric potentials, and then the computation of the conductivity is carried out. Moreover, this approach can also be used to calculate effective permittivity of material when a static field is …
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Solution of a Second Order Elliptic Partial Differential Equation with Varying Complex Coefficients: An Application for Computing Effective Complex Electrical Properties of Materials represented by 3D Images
… an energy function which is minimised using the Conjugate Gradient algorithm. It allows to obtain the electric potentials, and then the computation of the conductivity is carried out. Moreover, this approach can also be used to calculate effective permittivity of material when a static field is …
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Kinetic modeling and automated optimization in microreactor systems
… complex conversion profile. A steepest descent algorithm is first used to optimize conversion and production rates. The steepest descent algorithm tends to move slowly up the production rate ridge, significantly reducing efficiency. This issue is overcome by using a Fletcher-Reeves conjugate …