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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.
31

Cooperative caching in local-area and wide-area networks /

Voelker, Geoffrey Michael, January 2000 (has links)
Thesis (Ph. D.)--University of Washington, 2000. / Vita. Includes bibliographical references (p. 140-150).
32

Dispositivos sensores em fibra para uso em refratometria

Kamikawachi, Ricardo Canute 10 2011 (has links)
Este trabalho descreve a produção e a caracterização de redes de período longo (LPG) e redes de Bragg corroídas como elemento sensor. Tanto a produção quanto às caracterizações das redes de período longo foram realizadas no Laboratório de Laser da UTFPR e a produção e caracterização das redes de Bragg corroídas foram realizadas no Laboratório de Óptica Coerente da Universidade de Aveiro, Portugal. São abordados aspectos referentes aos princípios de produção e funcionamento do dispositivo. São apresentados os resultados obtidos na produção e na caracterização das redes, bem como os sistemas experimentais desenvolvidos para estes fins. O método empregado para a escrita das redes de período longo foi o da aplicação ponto-a-ponto de um arco elétrico, sendo produzidas redes com períodos de 598 e 600 μm operando na terceira janela de transmissão em torno de 1,55 μm. As redes de período longo e as redes de Bragg corroídas foram caracterizadas quanto as suas sensibilidades ao índice de refração, temperatura e deformações longitudinais (esta última caracterização foi realizada apenas para as redes de período longo), assim com a sensibilidade cruzada a estes parâmetros. A resposta das redes de período longo em função da variação do índice de refração do meio externo em duas diferentes situações, uma na presença de gasolina em ambiente hídrico e outra na presença de vapores de hidrocarbonetos ambiente atmosférico, indica a possibilidade da utilização deste dispositivo na detecção de vazamentos de hidrocarbonetos em refinarias ou postos de abastecimentos. Estas redes também foram caracterizadas para monitorar a concentração de cromo (III e VI) em soluções aquosas, os resultados indicam a possibilidades de monitorar em tempo real os processos de tratamento destes produtos, e assim otimizar este processo. As redes de Bragg foram utilizadas para a caracterização de propriedades ópticas de materiais, o resultado obtido para o etanol mostrou boa concordância com os valores apresentados na literatura, indicando que esta é uma técnica adequada para este fim. / This work describes the production and characterization of long period gratings (LPG) and etched fiber Bragg gratings as sensors. Both the production and characterization were carried out at the Laser Laboratory of UTFPR and the production and characterization of etched fiber Bragg gratings were carried out at Coherent Optics Laboratory of University of Aveiro, Portugal. Aspects concerning to the production and operation principles are shown. The results obtained from the grating production and characterization, as well as the experimental set-up developed to these goals are presented. The method used to write the gratings was the application of point-to-point electrical arch discharge, resulting in grating periods of 598 and 600 μm operating at the third window transmission around 1.55 μm. The long period gratings and the etched fiber Bragg gratings were characterized as a function of modification on the refractive index of the external surrounding environment, of temperature changes and strain (this last parameter was carried out only for long period gratings), the cross sensitivity also was characterized. The refractive index response of long period grating at two different conditions, one of them for presence of gasoline blend in water environment and another one for vapors of some hydrocarbon in closed container, points to the use of this device for hydrocarbon leakage detection at refineries and gas stations. Long period gratings e results obtained for ethanol agrees with the data find in literature, showing that this is a good technique for this goal.
33

Dispositivos sensores em fibra para uso em refratometria

Kamikawachi, Ricardo Canute 10 2011 (has links)
Este trabalho descreve a produção e a caracterização de redes de período longo (LPG) e redes de Bragg corroídas como elemento sensor. Tanto a produção quanto às caracterizações das redes de período longo foram realizadas no Laboratório de Laser da UTFPR e a produção e caracterização das redes de Bragg corroídas foram realizadas no Laboratório de Óptica Coerente da Universidade de Aveiro, Portugal. São abordados aspectos referentes aos princípios de produção e funcionamento do dispositivo. São apresentados os resultados obtidos na produção e na caracterização das redes, bem como os sistemas experimentais desenvolvidos para estes fins. O método empregado para a escrita das redes de período longo foi o da aplicação ponto-a-ponto de um arco elétrico, sendo produzidas redes com períodos de 598 e 600 μm operando na terceira janela de transmissão em torno de 1,55 μm. As redes de período longo e as redes de Bragg corroídas foram caracterizadas quanto as suas sensibilidades ao índice de refração, temperatura e deformações longitudinais (esta última caracterização foi realizada apenas para as redes de período longo), assim com a sensibilidade cruzada a estes parâmetros. A resposta das redes de período longo em função da variação do índice de refração do meio externo em duas diferentes situações, uma na presença de gasolina em ambiente hídrico e outra na presença de vapores de hidrocarbonetos ambiente atmosférico, indica a possibilidade da utilização deste dispositivo na detecção de vazamentos de hidrocarbonetos em refinarias ou postos de abastecimentos. Estas redes também foram caracterizadas para monitorar a concentração de cromo (III e VI) em soluções aquosas, os resultados indicam a possibilidades de monitorar em tempo real os processos de tratamento destes produtos, e assim otimizar este processo. As redes de Bragg foram utilizadas para a caracterização de propriedades ópticas de materiais, o resultado obtido para o etanol mostrou boa concordância com os valores apresentados na literatura, indicando que esta é uma técnica adequada para este fim. / This work describes the production and characterization of long period gratings (LPG) and etched fiber Bragg gratings as sensors. Both the production and characterization were carried out at the Laser Laboratory of UTFPR and the production and characterization of etched fiber Bragg gratings were carried out at Coherent Optics Laboratory of University of Aveiro, Portugal. Aspects concerning to the production and operation principles are shown. The results obtained from the grating production and characterization, as well as the experimental set-up developed to these goals are presented. The method used to write the gratings was the application of point-to-point electrical arch discharge, resulting in grating periods of 598 and 600 μm operating at the third window transmission around 1.55 μm. The long period gratings and the etched fiber Bragg gratings were characterized as a function of modification on the refractive index of the external surrounding environment, of temperature changes and strain (this last parameter was carried out only for long period gratings), the cross sensitivity also was characterized. The refractive index response of long period grating at two different conditions, one of them for presence of gasoline blend in water environment and another one for vapors of some hydrocarbon in closed container, points to the use of this device for hydrocarbon leakage detection at refineries and gas stations. Long period gratings e results obtained for ethanol agrees with the data find in literature, showing that this is a good technique for this goal.
34

Microsoft Windows Server 2003 security enhancements and new features

Montehermoso, Ronald Centeno 09 1900 (has links)
Approved for public release; distribution is unlimited. / The purpose of this thesis is to discuss the new features and enhancements of Windows Server 2003. Windows NT and Windows 2000 were known to have numerous security vulnerabilities; hence Microsoft focused on improving security by making Windows Server 2003 "secure by design, secure by default, secure in deployment." This thesis examines the differences between the five unique editions of the Windows Server 2003 family. Some of the pros and cons of migrating to Windows Server 2003 are highlighted. The author hopes this study will assist information technology professionals with their decision on whether or not to upgrade to this latest version of Microsoft's flagship network operating system. / Lieutenant Commander, United States Navy
35

The internet as a strategic business management tool

14 August 2012 (has links)
M.Comm. / This study was conducted with the intent of understanding and evaluating the commercial use and possibilities that the Internet offers, as well as the strategic approach businesses should take when commencing with electronic commerce on the Internet. The potential value of Intranets and Extranets has also been examined briefly. The Internet is a very useful mechanism for marketing as well as sales of products or services on a domestic or international basis. Various other commercial possibilities and uses exist for the Internet, as well as for its derivatives — the Intranet and Extranet. In the fiercely competitive market of today, companies research, develop and invest resources in various methods and tools in the hope to gain competitive advantage over their rivals. The Internet, Intranet and Extranet, used in isolation or conjunction, pose an extremely attractive alternative to gaining competitive advantage in a specific sector or market niche.The success of the Internet as a business tool depends directly on the overall business strategy that is driving the approach. For optimum success the main business strategy must be aligned with the Information Technology Strategy, and especially include thorough consideration as well as planning when implementing the Internet or one of its derivatives as a business tool.
36

Reliable and secure data transport in large scale wireless networks of embedded devices

Naik, Vinayak Shashikant, January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 105-111).
37

Wide-area route control for online services

Valancius, Vytautas 04 May 2012 (has links)
Accelerated by on-demand computing, the number and diversity of the Internet services is increasing. Such online services often have unique requirements for the underlying wide-area network: For instance, online gaming service might benefit from low delay and jitter paths to client, while online data backup service might benefit from cheaper paths. Unfortunately, today's Internet does not accommodate fine-grained, service-specific wide-area route control. In this dissertation, I achieve the following goals: 1) improve the access to the routes, 2) quantify the benefits of fine-grained route control, and 3) evaluate the efficiency of current payment schemes for the wide-area routes. * Improving access to wide-area route control. Online services face significant technological and procedural hurdles in accessing the routes: Each service in need to control the Internet routes, has to obtain own equipment, Internet numbered resources, and establish contracts with upstream ISPs. In this dissertation, I propose and describe implementation and deployment of a secure and scalable system which provides on-demand access to the Internet routes. In setting such as cloud data center, the system can support multiple online services, providing each service with an illusion of direct connectivity to the neighboring Internet networks, which, for all practical purposes, allows services to participate fully in the Internet routing. * Quantifying the benefits of fine-grained route control. Even if online services are presented with wide-area route choice, it is not clear how much tangible benefit such choice provides. Most modern Online Service Providers (OSP) rely primarily on the content routing to improve network performance between the clients and the replicas. In this dissertation, I quantify the potential benefit the OSPs can gain if they perform a joint network and content routing. Among other findings, I find that by performing joint content and network routing, OSPs can achieve 22% larger latency reduction than can be obtained by content routing alone. * Modeling and evaluating the efficiency of the current payment schemes for wide-area routes. Finally, increasing diversity and sophistication of the online services participating in the Internet routing poses a challenge to payment models used in today's Internet. Service providers today charge business customers a blended rate: a single, "average" price for unit of bandwidth, without regard to cost or value of individual customer's flows. In my dissertation, I set to understand how efficient this payment model is and if more granular payment model, accounting for the cost and value of different flows could increase the ISP profit and the consumer surplus. I develop an econometric demand and cost model and map three real-world ISP data sets to it. I find that ISPs can indeed improve the economic efficiency with just a few pricing tiers.
38

Characterisation of end-to-end performance for web-based file server respositories /

Mascarenhas da Veiga Alves, Manoel Eduardo. January 2001 (has links) (PDF)
Thesis (M.Eng.Sc.)--University of Adelaide, Dept. of Electrical and Electronic Engineering, 2001. / Bibliography: leaves 128-135.
39

Scheduling algorithms for resilient packet ring networks with video transport applications /

Zhu, Jian, January 1900 (has links)
Thesis (M. App. Sc.)--Carleton University, 2005. / Includes bibliographical references (p. 71-76). Also available in electronic format on the Internet.
40

Microsoft Windows Server 2003 : security enhancements and new features /

Montehermoso, Ronald Centeno. January 2004 (has links) (PDF)
Thesis (M.S. in Information Technology Management)--Naval Postgraduate School, Sept. 2004. / Thesis Advisor(s): Douglas E. Brinkley. Includes bibliographical references (p. 111-118). Also available online.

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