Thesis (M.S.)--University of North Carolina at Wilmington, 2003. / Includes bibliographical references (leaf : [37]).

Thesis (M.S.)--University of North Carolina at Wilmington, 2003. / Includes bibliographical references (leaf : 44).

Intelligent programming tutors have proven to be an economically viable and effective means of assisting novice programmers overcome learning difficulties. However, the large-scale use of intelligent programming tutors has been impeded by the high developmental costs associated with building intelligent programming tutors. The research presented in this thesis forms part of a larger initiative aimed at reducing these costs by building a generic architecture for the development of intelligent programming tutors. One of the facilities that must be provided by the generic architecture is the automatic generation of solutions to programming problems. The study presented in the thesis examines the use of genetic programming as means of inducing solution algorithms to novice programming problems. The scope of the thesis is limited to novice procedural programming paradigm problems requiring the use of arithmetic, string manipulation, conditional, iterative and recursive programming structures. The methodology employed in the study is proof-by-demonstration. A genetic programming system for the induction of novice procedural solution algorithms was implemented and tested on randomly chosen novice procedural programming problems. The study has identified the standard and advanced genetic programming features needed for the successful generation of novice procedural solution algorithms. The outcomes of this study include the derivation of an internal representation language for representing procedural solution algorithms and a high-level programming problem specification format for describing procedural problems, in the generic architecture. One of the limitations of genetic programming is its susceptibility to converge prematurely to local optima and not find a solution in some cases. The study has identified fitness function biases against certain structural components that are needed to find a solution, as an additional cause of premature convergence in this domain. It presents an iterative structure-based algorithm as a solution to this problem. This thesis has contributed to both the fields of genetic programming and intelligent programming tutors. While genetic programming has been successfully implemented in various domains, it is usually applied to a single problem within that domain. In this study the genetic programming system must be capable of solving a number of different programming problems in different application domains. In addition to this, the study has also identified a means of overcoming premature convergence caused by fitness function biases in a genetic programming system for the induction of novice procedural programming algorithms. Furthermore, although a number of studies have addressed the student modelling and pedagogical aspects of intelligent programming tutors, none have examined the automatic generation of problem solutions as a means of reducing developmental costs. Finally, this study has contributed to the ongoing research being conducted by the artificial intelligence in education community, to test the effectiveness of using machine learning techniques in the development of different aspects of intelligent tutoring systems. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2004.

The development of a simple efficient Pulse Width Modulation (PWM) modulator has been a goal for many research workers. In general three techniques have been used, namely; the analogue triangular wave technique; the use of look-up tables, and the use of Analogue to Digital converters together with analogue circuitry. The modulator described in this thesis is based on an iterative numerical algorithm, and is thus fundamentally different from all previous techniques. The algorithm is limited only by the speed and precision of the associated digital circuitry and can achieve higher modulating frequencies with greater accuracy than can be realised using any of the methods that have previously been investigated. The use of high switching frequencies simplifies the design of filters to reduce both unwanted harmonics and acoustic noise. In this thesis, an equation of a multiphase digital oscillator is derived which is simple to implement and will operate over a wide range of frequencies. The conditions for stable oscillation are derived, and two classes of oscillator are developed. It is shown how the frequency and amplitude of oscillations can be independently and continuously varied. The errors in computing the amplitude and frequency are analysed, and are shown to be cyclic. Upper bounds for the amplitude errors are derived. Single and three phase PWM modulators are described and the implementation procedures for their practical realisation are developed. Two specific implementations of the algorithm are investigated and experimental results confirm theoretical analyses. The algorithm can be incorporated in the Space Vector Modulation (SVM) method of PWM, to improve the resolution at low speeds and to enable the SVM technique to be applied at high gear ratios. A 3-phase 16-bit PWM modulator was built and operated satisfactorily with a pulse switching frequency of 20 kHz and an output frequency range of 1000:1. / Thesis (Ph.D.)-University of Natal, Durban, 1989.

Thesis (M.S. )--Duquesne University, 2007. / Title from document title page. Abstract included in electronic submission form. Includes bibliographical references (p. 59-61) and index.

Thesis (M.S.)--Texas State University--San Marcos, 2008. / Vita. Includes bibliographical references (leaves 50-51). Also available on microfilm.

Thesis (Ph. D.)--Aerospace Engineering, Georgia Institute of Technology, 2009. / Committee Chair: Olivier A. Bauchau; Committee Member: Andrew Makeev; Committee Member: Carlo L. Bottasso; Committee Member: Dewey H. Hodges; Committee Member: Massimo Ruzzene. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Thesis (Ph. D.)--Industrial and Systems Engineering, Georgia Institute of Technology, 2006. / Parker, R. Gary, Committee Member ; Shapiro, Alexander, Committee Member ; Nemirovski, Arkadi, Committee Member ; Green, William, Committee Member ; Monteiro, Renato, Committee Chair.

by Dimitri P. Bertsekas, John N. Tsitsiklis, Michael Athans. / "December, 1983." / Bibliography: p. 40-42. / NSF-ECS-8217668 ONR/N00014-77-C-0532(NR 041-519)

Orientador: Alvaro Rodolfo De Pierro / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 2018-08-05T18:58:18Z (GMT). No. of bitstreams: 1 Martinez_AnaGabriela_D.pdf: 800274 bytes, checksum: 9d484ffeb59df3623e4bb55d8c8fb1a1 (MD5) Previous issue date: 2006 / Resumo: A detecção de descontinuidades e um problema que aparece em muitas áreas de aplicação. Exemplos disto são os métodos de Fourier em tomografia computa dorizada, inversão em ressonância magnetica e as leis de conservação em qua»c~oes diferenciais. A determina»c~ao precisa dos pontos de descontinuidade e essencial para obter converg^encia exponencial da serie de Fourier para fun»c~oes cont³nuas por partes e evitar assim os efeitos do conhecido fen^omeno de Gibbs. Nos trabalhos de Wei et al. de 1999 e 2004 foram desenvolvidos ¯ltros polinomiais para reconstruir funções a partir de seus coeficientes de Fourier. No trabalho de Wei et al. do 2005 estes filtros foram usados para construir metodos iterativos rapidos para a detecção de de- scontinuidades. Nesta tese são introduzidos filtros mais gerais baseados em fun»c~oes splines, que conseguem maior precis~ao que aqueles apresentados em esses trabalhos e também são apresentados os correspondentes metodos iterativos para as descon- tinuidades. S~ao obtidas tambem estimativas para os erros assim como experi^encias numericas que validam os algoritmos. Mostra-se tambem um novo metodo que ap- resenta um melhor desempenho que aqueles baseados na serie parcial conjugada de Fourier usados nos trabalhos de Gelb e Tadmor / Abstract: Detecting discontinuities from Fourier coefficients is a problem that arises in several areas of application. Important examples are Fourier methods in Computed Tomography, Nuclear Magnetic Resonance Inversion and Conservation Law Differential Equations. Also, the knowledge of the precise location of the discontinuity points is essential to obtain exponential convergence of the Fourier series for a piecewise continuous function, avoiding the well known Gibbs phenomenon. In the work of Wei et al. (1999, 2004), polynomial filters were developed to reconstruct functions from their Fourier coefficients. In the work of Wei et. al. (2005), these fillters were used to develop fast iterative methods for discontinuity detection. In this thesis we introduce more general spline based filters, that achieve higher accuracy than those works, and the corresponding iterative methods for the discontinuities. Estimates for the errors are presented as well as many numerical experiments validating the algorithms. Also, we show that a new and simple method, not using any nonlinear solver, performs better than those based on the conjugate Fourier series as in the work of Gelb and tadmor / Doutorado / Analise Numerica / Doutor em Matemática Aplicada