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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

An improved method for simulation of vehicle vibration using a journey database and wavelet analysis for the pre-distribution testing of packaging

Griffiths, Katharine Rhiannon January 2013 (has links)
Vehicle vibration is inherently random and non-stationary with a non-Gaussian distribution. In addition, variations in vehicle parameters, product payloads and distribution journeys mean that the characteristics of vibration are not identical for all distribution journeys. Because vehicle vibration and shock are key causes of damage during distribution, their simulation in pre-distribution testing is vital in order to ensure that adequate protection is provided for transported products. The established method set out in the current testing standards utilises a global set of averaged accelerated power spectral density spectra to construct random vibration signals. These signals are stationary with Gaussian distributions and, therefore, do not fully represent actual vehicle vibration, only an average. The aim of the investigation, reported on in this Thesis, was to create an improved test regime for simulating vehicle vibration for pre-distribution testing of packaging. This aim has been achieved through the construction of representative tests and the creation of realistic simulations with statistical significance. A journey database has been created, in which historic road profile data along with a quarter vehicle model have been used to approximate a known vehicle’s vibration on a specific distribution journey. Additionally, a wavelet decomposition method, in which wavelet analysis is used to decompose the approximate vehicle vibration in to a series of Gaussian approximations of varying amplitude and spectral content, has been developed. Along with theoretical work, case studies have been undertaken in order to validate the test regime.
72

Conversão de voz baseada na transformada wavelet / Conversão de voz baseada na transformada wavelet

Vieira, Lucimar Sasso 16 April 2007 (has links)
Dentre as inúmeras técnicas de conversão de voz utilizadas atualmente, aquelas baseadas em bancos de filtros wavelet, associadas com redes neurais artificiais,têm se destacado. Este trabalho se concentra em tais técnicas, realizando um estudo que relaciona qual a melhor wavelet para conversão de determinados padrões de voz, apresentando uma análise detalhada de quais são as características que levam a estes resultados. Os testes são realizados com vozes da base de dados TIMIT do Linguistic Data Consortium (LDC). / Dentre as inúmeras técnicas de conversão de voz utilizadas atualmente, aquelas baseadas em bancos de filtros wavelet, associadas com redes neurais artificiais, têm se destacado. Este trabalho se concentra em tais técnicas, realizando um estudo que relaciona qual a melhor wavelet para conversão de determinados padrões de voz, apresentando uma análise detalhada de quais são as características que levam a estes resultados. Os testes são realizados com vozes da base de dados TIMIT do Linguistic Data Consortium (LDC).
73

Wavelets and frames.

January 2004 (has links)
Shea Yuen Cheuk. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 91-94). / Abstracts in English and Chinese. / Introduction --- p.5 / Chapter 1 --- Prelimaries --- p.9 / Chapter 1.1 --- Basic Notations --- p.9 / Chapter 1.2 --- Multiresolution Analysis --- p.12 / Chapter 1.3 --- Orthonormal Wavelets --- p.17 / Chapter 1.4 --- Theory of Frames --- p.24 / Chapter 2 --- Construction of Orthonormal Wavelets --- p.33 / Chapter 2.1 --- Compactly Supported Smooth Orthonormal Wavelet in R --- p.33 / Chapter 2.2 --- Compactly Supported Smooth Orthonormal Wavelet in R2 --- p.40 / Chapter 3 --- Wavelet Frames --- p.51 / Chapter 3.1 --- Basic Properties --- p.51 / Chapter 3.2 --- Dual Wavelet Frame --- p.56 / Chapter 3.3 --- Canonical Dual Frame --- p.66 / Chapter 3.4 --- Oversampling --- p.69 / Chapter 4 --- MRA-Based Wavelet Frames --- p.74 / Chapter 4.1 --- Definitions --- p.74 / Chapter 4.2 --- Tight Frames Constructed by MRA --- p.77 / Chapter 4.3 --- Approximation Order and Vanishing Moments for Wavelet Frames --- p.82 / Chapter 4.4 --- Construction of MRA-Based Wavelet Frames --- p.85 / Bibliography --- p.91
74

Wavelet-based semiconductor device simulation.

January 1997 (has links)
by Pun Kong-Pang. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 94-[96]). / Acknowledgement --- p.i / Abstract --- p.iii / List of Tables --- p.vii / List of Figures --- p.viii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Role of Device Simulation --- p.2 / Chapter 1.2 --- Classification of Device Models --- p.3 / Chapter 1.3 --- Sections of a Typical Simulator --- p.6 / Chapter 1.4 --- Arrangement of This Thesis --- p.7 / Chapter 2 --- Classical Physical Model --- p.9 / Chapter 2.1 --- Carrier Densities --- p.12 / Chapter 2.2 --- Space Charge --- p.14 / Chapter 2.3 --- Carrier Mobilities --- p.15 / Chapter 2.4 --- Generation and Recombination --- p.17 / Chapter 2.5 --- Modeling of Device Boundaries --- p.20 / Chapter 2.6 --- Limits of Classical Device Modeling --- p.22 / Chapter 3 --- Computational Aspects --- p.23 / Chapter 3.1 --- Normalization --- p.24 / Chapter 3.2 --- Discretization --- p.26 / Chapter 3.2.1 --- Finite Difference Method --- p.26 / Chapter 3.2.2 --- Finite Element Method --- p.27 / Chapter 3.3 --- Nonlinear Systems --- p.28 / Chapter 3.3.1 --- Newton's Method --- p.28 / Chapter 3.3.2 --- Gummel's Method and its modification --- p.29 / Chapter 3.3.3 --- Comparison and discussion --- p.30 / Chapter 3.4 --- Linear System and Sparse Matrix --- p.32 / Chapter 4 --- Cubic Spline Wavelet Collocation Method for PDEs --- p.34 / Chapter 4.1 --- Cubic spline scaling functions and wavelets --- p.35 / Chapter 4.1.1 --- Approximation for a function in H2(I) --- p.43 / Chapter 4.2 --- Wavelet interpolation --- p.45 / Chapter 4.2.1 --- Interpolant operator Ivo in Vo --- p.45 / Chapter 4.2.2 --- Interpolation operator IWjf in Wj --- p.47 / Chapter 4.3 --- Derivative Matrices --- p.51 / Chapter 4.3.1 --- First derivative matrix --- p.51 / Chapter 4.3.2 --- Second derivative matrix --- p.53 / Chapter 4.4 --- Wavelet Collocation Method for Solving Device Equations --- p.55 / Chapter 4.4.1 --- Steady state solution --- p.57 / Chapter 4.4.2 --- Transient solution --- p.58 / Chapter 4.5 --- Reducing Collocation Points --- p.59 / Chapter 4.5.1 --- Error evaluation --- p.59 / Chapter 4.5.2 --- Deleting collocation points --- p.61 / Chapter 5 --- Numerical Results --- p.64 / Chapter 5.1 --- P-N Junction Diode --- p.64 / Chapter 5.1.1 --- Steady state solution --- p.69 / Chapter 5.1.2 --- Transient solution --- p.76 / Chapter 5.1.3 --- Convergence --- p.79 / Chapter 5.2 --- Bipolar Transistor --- p.81 / Chapter 5.2.1 --- Boundary Model --- p.82 / Chapter 5.2.2 --- DC Solution --- p.83 / Chapter 5.2.3 --- Transient Solution --- p.89 / Chapter 6 --- Conclusions --- p.92 / Bibliography --- p.94
75

Shape representation based on wavelet skeleton

You, Xinge 01 January 2004 (has links)
No description available.
76

Resolving Crystal Structure of Macro Molecule with Wavelets in Simulated Annealing

Wu, Cheng-Hui 16 July 2002 (has links)
On account of ¡§the X-ray Phase Problem¡¨, it¡¦s impossible to get the electronic density by inverse Fourier transformation(IFT). And the crystal structure of molecule can¡¦t be solved by IFT. There are many methods to overcome the problem, such as Direct Method, Heavy Atom, and Simulated Annealing. But for macro-molecules, we still face a great challenge due to tremendous computing load. We propose a method by using wavelets to resolve the electronic density. We hope the multiresolution nature of wavelets can reduce the computing load for simulated annealing method.
77

Function estimation via wavelets in the presence of interval censoring /

Song, Changyong, January 1998 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves 85-87). Also available on the Internet.
78

Multi-rank wavelet filters

Leung, Hung-kwan. January 2001 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 80-81).
79

A wavelet-based prediction technique for concealment of loss-packet effects in wireless channels /

Garantziotis, Anastasios. January 2002 (has links) (PDF)
Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, June 2002. / Thesis advisor(s): Murali Tummala, Robert Ives. Includes bibliographical references (p. 89-90). Also available online.
80

Approximation to random process by wavelet basis.

Li, Zheng. January 2008 (has links)
Thesis (Ph.D.)--Brown University, 2008. / Vita. Advisor : Donald McClure. Includes bibliographical references (leaves 87-90).

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