Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains xi, 75 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 69-74).

Thesis (M.S.)--West Virginia University, 2003. / Title from document title page. Document formatted into pages; contains ix, 64 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 62-64).

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains x, 71 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 64-68).

SANTOS, M. C. Experimentos Computacionais com Implementações de Conjunto por Endereçamento Direto e o Problema de Conjunto Independente Máximo. 2013. 78 f. Dissertação (Mestrado em Ciência da Computação) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2013. / Submitted by Daniel Eduardo Alencar da Silva (dealencar.silva@gmail.com) on 2015-01-23T19:19:39Z No. of bitstreams: 1 2013_dis_mcsantos.pdf: 1370695 bytes, checksum: f82fbf8bcae3901a15066e6d39ac2720 (MD5) / Approved for entry into archive by Rocilda Sales(rocilda@ufc.br) on 2015-09-23T16:28:47Z (GMT) No. of bitstreams: 1 2013_dis_mcsantos.pdf: 1370695 bytes, checksum: f82fbf8bcae3901a15066e6d39ac2720 (MD5) / Made available in DSpace on 2015-09-23T16:28:47Z (GMT). No. of bitstreams: 1 2013_dis_mcsantos.pdf: 1370695 bytes, checksum: f82fbf8bcae3901a15066e6d39ac2720 (MD5) Previous issue date: 2013 / The use of bit vectors is a usual practice for represent sets by direct addressing with the aim of reduce memory consumed and improve efficiency of applications with the use of bit parallel techniques. In this text, we study implementations for represent sets by direct addressed. The basic structure in this implementations is the bit vector. Besides that basic implementation, we implement two variations also. The first one is a stratification of the bit vector, while the second uses a hash table. The operations linked to the implemented structure are include and remove an element and the union and intersection of two sets. Especial attention is given to the use of bit parallel in this condition. The implementation of the different structures in this work use an base interface and a base abstract class, where the operations are defined and the bit parallel is used. An experimental comparative between this structures is carry out using enumerative algorithms for the maximum stable set problem. Two approaches are used in the implementation of the enumerative algorithms for the maximum stable set problem, both using the bit parallel in the representation of the graph and on the operations with subsets of vertices. The first one is a known branch-and-bound algorithm and the second uses the Russian dolls method. In both cases, the use of bit parallel improve efficiency when the lower bounds are calculated based in a clique cover of the vertices. The results of computational experiments are presented as comparison between the two algorithms and as an assessment of the structures implemented. These results show that the algorithm based on the method Russian Dolls is more efficient regarding runtime and the memory consumed. Furthermore, the experimental results also show that the use stratification and hash tables also allow more efficiency in the case of sparse graphs. / A utilização de vetores de bits é prática corrente na representação de conjuntos por endereçamento direto com o intuito de reduzir o espaço de memória necessário e melhorar o desempenho de aplicações com uso de técnicas de paralelismo em bits. Nesta dissertação, examinamos implementações para representação de conjuntos por endereçamento direto. A estrutura básica nessas implementações é o vetor de bits. No entanto, além dessa estrutura básica, implementamos também duas variações. A primeira delas consiste em uma estratificação de vetores de bits, enquanto a segunda emprega uma tabela de dispersão. As operações associadas às estruturas implementadas são a inclusão ou remoção de um elemento do conjunto e a união ou interseção de dois conjuntos. Especial atenção é dada ao uso de paralelismo em bits nessas operações. As implementações das diferentes estruturas nesta dissertação utilizam uma interface e uma implementação abstrata comuns, nas quais as operações são especificadas e o paralelismo em bits é explorado. A diferença entre as implementações está apenas na estrutura utilizada. Uma comparação experimental é realizada entre as diferentes estruturas utilizando algoritmos enumerativos para o problema de conjunto independente máximo. Duas abordagens são utilizadas na implementação de algoritmos enumerativos para o problema de conjunto independente máximo, ambas explorando o potencial de paralelismo em bits na representação do grafo e na operação sobre subconjuntos de vértices. A primeira delas é um algoritmo do tipo {em branch-and-boound} proposto na literatura e a segunda emprega o método das bonecas russas. Em ambos os casos, o uso de paralelismo em bits proporciona ganhos de eficiência quando empregado no cálculo de limites inferiores baseados em cobertura por cliques. Resultados de experimentos computacionais são apresentados como forma de comparação entre os dois algoritmos e como forma de avaliação das estruturas implementadas. Esses resultados permitem concluir que o algoritmo baseado no método das bonecas russas é mais eficiente quanto ao tempo de execução e quanto ao consumo de memória. Além disso, os resultados experimentais mostram também que o uso de estratificação e tabelas de dispersão permitem ainda maior eficiência no caso de grafos com muito vértices e poucas arestas.

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A Thesis Submitted to the Faculty of Engineering University of Witwatersrand, Johannesburg for the Degree of Doctor of Philosophy. Johannesburg 1977 / No abstract

Thesis (M.S.)--West Virginia University, 2000. / Title from document title page. Document formatted into pages; contains vi, 81 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 71-75).

Un des plus grands challenges dans le domaine de l’information quantique est la génération, manipulation et détection de plusieurs qubits sur des micro-puces. On assiste ainsi à un véritable essor des technologies pour l’information quantique et pour transmettre l’information, les photons ont un grand avantage sur les autres systèmes, grâce à leur grande vitesse et leur immunité contre la décohérence.Mon travail de thèse porte sur la conception, fabrication et caractérisation d’une source de photons intriqués en matériaux semiconducteurs d’une très grande compacité. Ce dispositif fonctionne à température ambiante, et émet dans la bande de longueurs d’onde télécom. Après une présentation des concepts fondamentaux (chap. 1), le chap. 2 explique la conception et la fabrication des dispositifs.Le chap. 3 présente les caractérisations opto-électroniques des échantillons pompés électriquement, et le chap. 4 les résultats des mesures de pertes et des caractérisations non-linéaires optiques (génération de seconde harmonique, conversion paramétrique spontanée et reconstruction de l’intensité spectrale jointe). Les chap. 5 et 6 se concentrent sur la caractérisation des états quantiques générés par un dispositif passif (démonstration de l’indiscernabilité et de l’intrication en énergie-temps) et leur utilisation dans un protocole de distribution de clés quantiques multi-utilisateurs (intrication en polarisation). Finalement le travail sur le premier dispositif produisant des pairs de photons dansles longueurs d’onde télécoms, injecté électriquement et fonctionnant à température ambiante est présenté (chap. 7). / One of the main issues in the domain of quantum information and communication is the generation,manipulation and detection of several qubits on a single chip. Several approaches are currentlyinvestigated for the implementation of qubits on different types of physical supports and a varietyof quantum information technologies are under development: for quantum memories, spectacularadvances have been done on trapped atoms and ions, while to transmit information, photons arethe ideal support thanks to their high speed of propagation and their almost immunity againstdecoherence. My thesis work has been focused on the conception, fabrication and characterization ofa miniaturized semiconductor source of entangled photons, working at room temperature and telecomwavelengths. First the theoretical concepts relevant to understand the work are described (chapter1). Then the conception and fabrication procedures are given (chapter 2). Chapter 3 presents theoptoelectronics characterization of the device under electrical pumping, and chapter 4 the resultson the optical losses measurements and the nonlinear optical characterization (second harmonicgeneration, spontaneous parametric down conversion and joint spectral intensity reconstruction).Chapters 5 and 6 focus on the characterization of the quantum state generated by a passive sample(demonstration of indistinguishability and energy-time entanglement) and its utilization in a multiuserquantum key distribution protocol (polarization entanglement). Finally the work on the firstelectrically driven photon pairs source emitting in the telecom range and working at room temperatureis presented (chapter 7).

Vita. / Digitized by Kansas Correctional Industries

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in partial fulfillment of the requirements for the degree of Master of Science in Engineering, School of Mechanical, Industrial & Aeronautical Engineering, 2017 / An investigation of polycrystalline diamond compact (PDC) cutter failures, which are industrially known as spalling, was conducted by exploring changes in the diamond layer architecture and edge geometry of the cutter. Layer architecture was investigated through the use of layered functionally graded (FG) structures. Twenty one FG variations were prepared by the tape casting method and sintered using a high-pressure, high-temperature press. The vertical borer test (VBX), a laboratory test method, was used to gauge the improvement in spall resistance of the FG specimens against the benchmarks. Due to cost constraints associated with VBX testing, of the 21 available specimens, only four variations were tested for spalling. Contrary to expectation, it was found that all four specimens spalled during VBX testing despite showing a slight improvement in the spall area. For this reason, this route was abandoned. It was concluded that the use of layered structures is not effective in resolving the spalling problem. The use of novel edge geometry was investigated by taking three standard products and creating new geometric profiles on the specimens using a spark erosion machine. Each profile comprised a depression on the front face of the cutter. The specimens with novel geometry were also tested on the VBX. The spall was found to be confined between the chamfer breach and the depression feature. The depression appeared to have stopped the spall from propagating beyond the allowable spall limit of 1.2mm. On the basis of this 3 finding, it was concluded that spalling was successfully resolved. It is recommended that further optimization of this solution should be explored in field testing. In addition, a cost-effective way to fabricate the geometric profiles on the cutters should be further investigated because creating specimens using the spark erosion machine was quite expensive. Therefore, it is not viable for fabrication of large production volumes / CK2018