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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.
261

A VLSI-nMOS hardware implementation of an IIR bandpass orthogonal digital filter

Kaake, Fadi M. January 1986 (has links)
No description available.
262

An Experimental Study of the Performance, Energy, and Programming Effort Trade-offs of Android Persistence Frameworks

Pu, Jing 16 August 2016 (has links)
One of the fundamental building blocks of a mobile application is the ability to persist program data between different invocations. Referred to as persistence, this functionality is commonly implemented by means of persistence frameworks. When choosing a particular framework, Android-the most popular mobile platform-offers a wide variety of options to developers. Unfortunately, the energy, performance, and programming effort trade-offs of these frameworks are poorly understood, leaving the Android developer in the dark trying to select the most appropriate option for their applications. To address this problem, this thesis reports on the results of the first systematic study of six Android persistence frameworks (i.e., ActiveAndroid, greenDAO, OrmLite, Sugar ORM, Android SQLite, and Realm Java) in their application to and performance with popular benchmarks, such as DaCapo. Having measured and analyzed the energy, performance, and programming effort trade-offs for each framework, we present a set of practical guidelines for the developer to choose between Android persistence frameworks. Our findings can also help the framework developers to optimize their products to meet the desired design objectives. / Master of Science
263

Orthogonal vs. Biorthogonal Wavelets for Image Compression

Rout, Satyabrata 19 September 2003 (has links)
Effective image compression requires a non-expansive discrete wavelet transform (DWT) be employed; consequently, image border extension is a critical issue. Ideally, the image border extension method should not introduce distortion under compression. It has been shown in literature that symmetric extension performs better than periodic extension. However, the non-expansive, symmetric extension using fast Fourier transform and circular convolution DWT methods require symmetric filters. This precludes orthogonal wavelets for image compression since they cannot simultaneously possess the desirable properties of orthogonality and symmetry. Thus, biorthogonal wavelets have been the de facto standard for image compression applications. The viability of symmetric extension with biorthogonal wavelets is the primary reason cited for their superior performance. Recent matrix-based techniques for computing a non-expansive DWT have suggested the possibility of implementing symmetric extension with orthogonal wavelets. For the first time, this thesis analyzes and compares orthogonal and biorthogonal wavelets with symmetric extension. Our results indicate a significant performance improvement for orthogonal wavelets when they employ symmetric extension. Furthermore, our analysis also identifies that linear (or near-linear) phase filters are critical to compression performance---an issue that has not been recognized to date. We also demonstrate that biorthogonal and orthogonal wavelets generate similar compression performance when they have similar filter properties and both employ symmetric extension. The biorthogonal wavelets indicate a slight performance advantage for low frequency images; however, this advantage is significantly smaller than recently published results and is explained in terms of wavelet properties not previously considered. / Master of Science
264

Ortho-ambivalence des groupes finis / Ortho-ambivalence of finite groups

Ntabuhashe Zahinda, Obed 16 May 2008 (has links)
Soient G un groupe fini et k un corps dont la caractéristique ne divise pas l’ordre de G. Il est établi, d’une part que pour que tous les caractères irréductibles de G soient réels, il faut et il suffit que G soit ambivalent; d’autre part, que pour que la restriction de l’involution canonique à chaque composante simple de l’algèbre de groupe kG soit une involution de première espèce, il faut et il suffit que G soit ambivalent. G est dit ortho-ambivalent par rapport à k si la restriction de l’involution canonique à chaque composante simple de l’algèbre de groupe kG est une involution orthogonale. Dans cette thèse, nous démontrons que les propositions suivantes sont équivalentes : (i) G est ortho-ambivalent par rapport à k ; (ii) G est totalement orthogonal ; (iii) G est ambivalent et tout caractère irréductible de G est de type 1 ; (iv) G est ambivalent et la somme des degrés des caractères irréductibles de G égale le nombre d’éléments de G dont les carrés sont égaux à l’élément neutre de G ; de plus, si la caractéristique de k est différente de 2, ces propositions sont équivalentes à la suivante : (v) G est ambivalent et le premier groupe de Witt tordu de la catégorie des kG-modules libres finiment engendrés munie d’une dualité définie en fonction de l’involution canonique sur kG est trivial. L’étude des 2-groupes spéciaux occupe une partie importante. Nous démontrons qu’un 2-groupe spécial ambivalent G d’application quadratique q est ortho-ambivalent par rapport à k si et seulement si pour toute forme linéaire s sur le centre de G (par rapport au corps à 2 éléments), l’invariant d’Arf de la forme quadratique induite par le transfert de q par s est nul. / Let G be a finite group and k a field whose characteristic does not divide the order of G. It is established, on the one hand that all irreducible characters of G are real if and only if G is ambivalent; in addition, that the restriction of the canonical involution on each simple component of the group algebra kG is an involution of first kind if and only if G is ambivalent. We say that G is ortho-ambivalent compared to k if the restriction of the canonical involution on each simple component of the group algebra kG is an orthogonal involution. In this thesis, we show that the following conditions are equivalent: (I) G is ortho-ambivalent compared to k; (II) G is totaly orthogonal; (III) G is ambivalent and any irreducible character of G is of type 1; (iv) G is ambivalent and the sum of the degrees of the irreducible characters of G equalizes the number of elements of G whose squares are equal to the neutral element of G; moreover, if the characteristic of k is different from 2, these conditions are equivalent to the following one: (v) G is ambivalent and the first twisted Witt group of the category of the free kG-modules finitely generated provided with a duality defined according to the canonical involution on kG is trivial. The study of the special 2-groups occupies a great part. We show that an ambivalent special 2-group G of quadratic application q is ortho-ambivalent compared to k if and only if for any linear form s on the center of G (compared to the field with 2 elements), the Arf invariant of the quadratic form induced by the transfer of q by s is null.
265

Pravoúhlá axonometrie pro střední školy / Orthogonal axonometry for secondary schools

Janišová, Lenka January 2019 (has links)
This work, which is intended for secondary school pupils and teachers, is fo- cused on orthogonal axonometry for pupils and teachers at secondary schools. The thesis consists of exercises, some of them are stepped in presentations and can be found on the attached CD. Templates of models that students can build themselves are included in the first exercises for better understanding. The text is supplemented by the development of orthogonal axonometry and an analysis of the current state of orthogonal axonometry education in the Czech Republic, based on a questionnaire survey and an analysis of textbooks. The theoretical part of the work was prepared for publication on the website. 1
266

Optical Orthogonal Signature Pattern Codes with Maximum Collision Parameter 2 and Weight 4

Sawa, Masanori 07 1900 (has links)
No description available.
267

Estimation of Orthogonal Regression Under Censored Data.

Ho, Chun-shian 19 July 2008 (has links)
The method of least squares has been used in general for regression analysis. It is usually assumed that the errors are confined to the dependent variable, but in many cases both dependent and independent variables are typically measured with some stochastic errors. The statistical method of orthogonal regression has been used when both variables under investigation are subject to stochastic errors. Furthermore, the measurements sometimes may not be exact but have been censored. In this situation doing orthogonal regression with censored data directly between the two variables, it may yield an incorrect estimates of the relationship. In this work we discuss the estimation of orthogonal regression under censored data in one variable and then provide a method of estimation and two criteria on when the method is applicable. When the observations satisfy the criteria provided here, there will not be very large differences between the estimated orthogonal regression line and the theoretical orthogonal regression line.
268

Orthogonal functionalization strategies in polymeric materials

Yang, Si Kyung 31 August 2009 (has links)
This thesis describes original research aimed at the development of highly efficient polymer functionalization strategies by introducing orthogonal chemistry within polymeric systems. The primary hypothesis of this thesis is that the use of click chemistries or noncovalent interactions can provide new and easy pathways towards the synthesis of highly functionalized polymers thereby addressing the shortcomings of traditional covalent functionalization approaches. To verify the hypothesis, the work presented in the following chapters of this thesis further explores previous methods of either covalent or noncovalent polymer functionalization described in Chapter 1. Chapters 2 and 3 present advanced methods of covalent polymer functionalization based on high-yielding and orthogonal click reactions: 1,3-dipolar cycloaddition, hydrazone formation, and maleimide-thiol coupling. All three click reactions employed can be orthogonal to one another and conversions can be quantitative, leading to the easy and rapid synthesis of highly functionalized polymers without interference among functional handles along the polymer backbones. The next two chapters focus on the noncovalent functionalization strategies for creating supramolecular block copolymers via the main-chain self-assembly of telechelic polymers. Novel synthetic methods to prepare telechelic polymers bearing terminal recognition motifs were developed through a combination of ROMP using functionalized ruthenium initiators and functionalized chain-terminators, and the resulting polymers were self-assembled to form supramolecular block copolymers. Chapter 4 demonstrates the formation of supramolecular multiblock copolymers via self-assembly of symmetrical telechelic polymers using metal coordination, while Chapter 5 demonstrates that supramolecular ABC triblock copolymers can be prepared by the self-assembly of a heterotelechelic polymer as the central block with two other complementary monotelechelic polymers using two orthogonal hydrogen bonding interactions. Chapter 6 presents a unique application of noncovalent functionalization approaches. The ultimate goal of this research is to develop a controlled polymerization method based on noncovalent templation. The initial attempts at the metal coordination-based template polymerization are presented in this chapter. Finally, Chapter 7 summarizes the findings in each chapter and presents the potential extensions of the orthogonal functionalization strategies developed in this thesis.
269

THE EQUIVALENCE PROBLEM FOR ORTHOGONALLY SEPARABLE WEBS ON SPACES OF CONSTANT CURVATURE

Cochran, Caroline 09 June 2011 (has links)
This thesis is devoted to creating a systematic way of determining all inequivalent orthogonal coordinate systems which separate the Hamilton-Jacobi equation for a given natural Hamiltonian defined on three-dimensional spaces of constant, non-zero curvature. To achieve this, we represent the problem with Killing tensors and employ the recently developed invariant theory of Killing tensors. Killing tensors on the model spaces of spherical and hyperbolic space enjoy a remarkably simple form; even more striking is the fact that their parameter tensors admit the same symmetries as the Riemann curvature tensor, and thus can be considered algebraic curvature tensors. Using this property to obtain invariants and covariants of Killing tensors, together with the web symmetries of the associated orthogonal coordinate webs, we establish an equivalence criterion for each space. In the case of three-dimensional spherical space, we demonstrate the surprising result that these webs can be distinguished purely by the symmetries of the web. In the case of three-dimensional hyperbolic space, we use a combination of web symmetries, invariants and covariants to achieve an equivalence criterion. To completely solve the equivalence problem in each case, we develop a method for determining the moving frame map for an arbitrary Killing tensor of the space. This is achieved by defining an algebraic Ricci tensor. Solutions to equivalence problems of Killing tensors are particularly useful in the areas of multiseparability and superintegrability. This is evidenced by our analysis of symmetric potentials defined on three-dimensional spherical and hyperbolic space. Using the most general Killing tensor of a symmetry subspace, we derive the most general potential “compatible” with this Killing tensor. As a further example, we introduce the notion of a joint invariant in the vector space of Killing tensors and use them to characterize a well-known superintegrable potential in the plane. xiii
270

Algoritmos evolutivos aplicados na alocação de recursos em Sistemas OFDMA

Bulgaroni, Caio Rodrigo Guimarães January 2017 (has links)
Orientador: Prof. Dr. Ivan Roberto Santana Casella / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2017. / A busca por transmissoes de dados em altas taxas é um fator indispensavel para a evolução dos sistemas de comunicação Wireless. Dessa forma, se faz necessario o estudo e desenvolvimento de novos metodos que visam aprimorar o desempenho desses sistemas. Uma tecnica bastante utilizada para atingir este objetivo é a OFDM (Orthogonal Frequency Division Multiplexing), onde é possivel aumentar a robustez do sistema a canais com desvanecimento seletivo em frequencia. Outra tecnica bastante interessante e difundida para este fim é a alocaação de recursos, que possibilita a otimização do uso dos recursos do sistema de forma a maximizar a taxa de transmissão (ou outro parametro do sistema de interesse). Neste sentido, este trabalho visa estudar o problema de alocação de recursos em sistemas Wireless e analisar algumas estrategias especificas para sistemas OFDM com multiplos usuarios como os sistemas OFDMA (Orthogonal Frequency Division Multiple Access) empregados no downlink das redes LTE (Long Term Evolution). Os estudos apresentados irão focar nos metodos de alocaçao de subportadoras e potencia propostos por Shen e, posteriormente, por Wong e nos metodos baseados em Algoritmos Geneticos (GA). / The search for high-speed data transmissions is an indispensable factor for the evolution of Wireless communication systems. Thus, it is necessary to study and develop new methods that aim to improve the performance of these systems. A technique widely used to achieve this goal is OFDM (Orthogonal Frequency Division Multiplexing), where it is possible to increase the robustness of the system to channels with frequency selective fading. Another very interesting and widespread technique for this purpose is the allocation of resources, which makes it possible to optimize the use of system resources in order to maximize the transmission rate (or other parameter of the system of interest). In this sense, this work aims to study the problem of resource allocation in Wireless systems and to analyze some specic strategies for multi-user OFDM systems such as the Orthogonal Frequency Division Multiple Access (OFDMA) systems used in the downlink of LTE (Long Term Evolution) networks. The studies presented will focus on the methods of subcarrier allocation and power proposed by Shen and later by Wong and in the methods based on genetic algorithms (GA).

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