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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.
451

Validação de métodos para coleta de espectro de emissividade no infravermelho de ondas curtas e termal utilizando um espectrorradiômetro de campo portátil / Validation of methods for collecting the emissivity spectrum in the short wave infrared and thermal infrared using a portable field spectroradiometer

Luján Iglesias, María January 2013 (has links)
Esta pesquisa tem como objetivo principal desenvolver uma rotina de procedimentos de coleta de dados espectrais utilizando um espectro radiômetro de campo portátil, μFTIR Model 102, desenvolvido pela empresa Design & Prototypes, o qual permite a aquisição de espectros infravermelhos de superfícies entre 2 e 14 μm. O equipamento foi utilizado para realizar leituras de radiância e calculo de emissividade, transmitância e refletância, utilizando uma amostra de quartzo, a qual apresenta uma curva de emissividade bem conhecida no infravermelho termal (região entre 8-14 μm). Foram realizadas leituras na amostra para diferentes condições de temperatura e umidade, tanto no campo como no laboratório com o fin de obter um completo protocolo para a calibração e coleta de dados. Embora o instrumento opere numa região mais ampla, este estudo apenas avalia os dados entre 7-14 μm onde a maioria dos instrumentos a bordo de plataformas aéreas e orbitais posiciona os detectores. / The main purpose of this research is to develop a routine procedure for data collection using a field spectral radiometer, μFTIR Model 102, developed by Design & Prototypes, which allows the acquisition of infrared spectra of surfaces between 2 and 14 μm. The instrument was used to perform lectures of radiances and calculation of emissivity, transmittance and reflectance, using a sample of quartz, which shows a very well-known curve of emissivity in the thermal infrared (region between 8-14 μm). Reading were taken in the sample for different conditions of temperature and humidity, both in the field and in the laboratory with the objective of get a complete protocol for calibration and data collection. Although the instrument operating in a wider region, this study evaluates the data between 7-14 μm where most of the instruments on board of airborne platforms and orbital detectors are positioned.
452

Reflorestamento no Brasil e o Protocolo de Quioto / Reforestation in Brazil and the Kioto Protocol

Gustavo D'Almeida Scarpinella 24 June 2002 (has links)
A questão das mudanças climáticas vem ganhando destaque e sendo mais discutida à medida que se caminha para a ratificação do Protocolo de Quioto. No presente trabalho é analisada a viabilidade de um projeto de reflorestamento candidato ao Mecanismo de Desenvolvimento Limpo, mecanismo de flexibilização proposto pelo Protocolo que permite a participação brasileira. São discutidos aspectos favoráveis e desfavoráveis à implementação de um projeto florestal, nas condições atuais. Para tal discussão propõe-se uma atividade de reflorestamento com espécies do gênero Eucalyptus, administrada por uma cooperativa florestal dentro da regional agrícola de Botucatu (SP). Os objetivos principais desta atividade são a obtenção de madeira para fins de serraria e a comercialização de créditos de carbono referentes ao volume de madeira serrada. Foram feitos cálculos de viabilidade econômica pela Taxa Interna de Retorno (TIR) e pelo Valor Presente Líquido (VPL) do projeto, com e sem o emprego do MDL. Verificou-se a viabilidade econômica nos dois casos, embora a diferença na receita não tenha sido considerável. Em projetos em que não há a participação do MDL, a TIR média foi de 7% para todas as áreas. Com a participação do MDL, houve uma variação da TIR de 6,2% a 7,3%, conforme as extensões das áreas adotadas e os preços pagos pela tonelada do carbono. Para pequenas áreas, o emprego do MDL pode inviabilizar o projeto. As atividades florestais para fins de serraria mostraram um rendimento muito baixo para o MDL, pelo fato de apenas um décimo da produção total ser aceito para comercialização dos créditos de carbono. / The issue of climate change wins relevance and brings controversy as the ratification of Kyoto Protocol approaches for most countries. Present work analyses feasibility for a reforesting project candidate for the Clean Development Mechanism (CDM). CDM is a flexibilization mechanism proposed in the Protocol wich allows Brazilian participation. Both favorable and unfavorable aspects are discussed for the implementation of a forest project under present conditions. For the purpose of this discussion, an activity of reforestation based on trees of the Eucalyptus species, managed by a forest cooperative society, in the agricultural region of Botucatu (SP). Main goal for such cooperative are obtained of lumber and commercialization of carbon credits relative to the quantity of lumber produced. Calculations for economic feasibility were carried out, producing the Internal Rate of Revenue (IRR) and the Present Net Worth (PNW), both under and out of the CDM. Economical feasibility were confirmed for both cases, although difference between revenues was not considerable. For projects with no CDM participation, average IRR was 7,0 per cent for all area extents. With CDM participation, the was a rate range between 6,2 and 7,3 per cent, according to the extent of submitted areas, and prices paid for ton of carbon. For small areas, CDM adoption can turn the project unfeasible. Forest activities for producing lumber showed low profitability for CDM, due to the fact that only one tenth of total production is accepted for commercialization of carbon credits.
453

Validação de métodos para coleta de espectro de emissividade no infravermelho de ondas curtas e termal utilizando um espectrorradiômetro de campo portátil / Validation of methods for collecting the emissivity spectrum in the short wave infrared and thermal infrared using a portable field spectroradiometer

Luján Iglesias, María January 2013 (has links)
Esta pesquisa tem como objetivo principal desenvolver uma rotina de procedimentos de coleta de dados espectrais utilizando um espectro radiômetro de campo portátil, μFTIR Model 102, desenvolvido pela empresa Design & Prototypes, o qual permite a aquisição de espectros infravermelhos de superfícies entre 2 e 14 μm. O equipamento foi utilizado para realizar leituras de radiância e calculo de emissividade, transmitância e refletância, utilizando uma amostra de quartzo, a qual apresenta uma curva de emissividade bem conhecida no infravermelho termal (região entre 8-14 μm). Foram realizadas leituras na amostra para diferentes condições de temperatura e umidade, tanto no campo como no laboratório com o fin de obter um completo protocolo para a calibração e coleta de dados. Embora o instrumento opere numa região mais ampla, este estudo apenas avalia os dados entre 7-14 μm onde a maioria dos instrumentos a bordo de plataformas aéreas e orbitais posiciona os detectores. / The main purpose of this research is to develop a routine procedure for data collection using a field spectral radiometer, μFTIR Model 102, developed by Design & Prototypes, which allows the acquisition of infrared spectra of surfaces between 2 and 14 μm. The instrument was used to perform lectures of radiances and calculation of emissivity, transmittance and reflectance, using a sample of quartz, which shows a very well-known curve of emissivity in the thermal infrared (region between 8-14 μm). Reading were taken in the sample for different conditions of temperature and humidity, both in the field and in the laboratory with the objective of get a complete protocol for calibration and data collection. Although the instrument operating in a wider region, this study evaluates the data between 7-14 μm where most of the instruments on board of airborne platforms and orbital detectors are positioned.
454

Melhorando o desempenho do ZRP em um cenário emergencial usando redes AD HOC

Leite, Luis Felipe Formiga 29 August 2014 (has links)
Submitted by Matheus Alves Bulhoes (matheus.bulhoes@ufpe.br) on 2015-05-12T14:36:25Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação_Luis_Final.pdf: 2794061 bytes, checksum: ca38ae8cdb5e52a8b28f84163a66bc6b (MD5) / Made available in DSpace on 2015-05-12T14:36:25Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação_Luis_Final.pdf: 2794061 bytes, checksum: ca38ae8cdb5e52a8b28f84163a66bc6b (MD5) Previous issue date: 2014-08-29 / Redes emergenciais são redes móveis utilizadas em cenários de catástrofes onde os meios de transmissão convencionais estão usualmente comprometidos. Neste contexto o estabelecimento de uma MANET (Mobile Ad Hoc Network) é a solução mais indicada para suprir a comunicação entre as equipes de resgate e organizações competentes. Atualmente existe uma gama de trabalhos que, através de simulações, avaliam o desempenho de protocolos de roteamento em cenários variados, alguns de desastres. O cenário apresentado por este trabalho é específico de uma situação de desastre, similar a uma ocorrência de deslizamento de terra. Acontecimentos como esse criam um ambiente com características particulares e, o roteamento usado deveria suprir da melhor forma esses fatores únicos. Portanto, este trabalho apresentou uma hipótese que o roteamento baseado em zonas pode ser a melhor escolha para o cenário proposto. Foi desenvolvido um novo protocolo com base no já existente Zone Routing Protocol e comparado através de métricas de desempenho com os protocolos AODV e DSDV, além do próprio ZRP. Ainda, objetivando modelar uma mobilidade mais condizente com a apresentada pelas equipes de resgate, foi desenvolvida uma adaptação do "disaster mobility model" para junto com o cenário sumarizar as características únicas desse ambiente e gerar simulações mais realistas. As simulações foram feitas com uma variação do número de nós entre os cenários, e a comparação dos protocolos foi analisada pelos valores atingidos por eles nas simulações em métricas de desempenho. Os resultados mostraram que o novo protocolo foi bastante superior ao seu original em todas as métricas, atingindo também um desempenho semelhante ou melhor que o AODV e o DSDV em packet delivery ratio, end to end delay e routing overhead. Dessa forma, concluiu-se que o novo protocolo desenvolvido alcançou seu objetivo, se tornando, entre os protocolos testados, uma opção viável para roteamento em redes emergenciais críticas.
455

Methodological assessment of the Critical Thermal Maximum (CTmax) of anuran larvae: interaction among the experimental heating rates, ontogeny and body mass / Estudo metodológico da Temperatura Crítica Máxima (CTmax) de larvas de anfíbios anuros: interação entre as taxas de aquecimento experimental, ontogenia e massa corpórea

Gustavo Adolfo Agudelo Cantero 31 October 2016 (has links)
Thermal limits for ectothermic animals displays a picture of the range of body temperatures that is tolerable by individuals before their locomotory capacity is impaired. However, thermal limits are not fixed and specific traits, but labile ones subjected to plastic adjustments and evolutionary change, and also are influenced by intrinsic and extrinsic factors of organisms, as well as by methodological factors inherent to experimental protocols. Even more, the influences of these factors on thermal limits have been commonly addressed independently in different taxa, and the extent by which multiple factors interact and affect thermal limits within taxa is poorly understood. Thus, the main aim of this work was to conduct a methodological assessment of the Critical Thermal Maximum (CTmax) by studying the influences of different experimental heating rates (ΔT’s), ontogeny, body mass, and the interaction among these factors on this trait. This matter was addressed on larvae of Physalaemus nattereri and Hypsiboas pardalis, two anuran species from the São Paulo State, southeastern Brazil, that differ in their phylogenetic background, ecological and life-history characteristics and inhabit environments with different thermal regimes. First, ΔT’s did affect averages and variances of CTmax in a species-specific manner. In addition, it was found a ΔT-dependent decreasing in CTmax at the end of metamorphosis in tadpoles of P. nattereri, because only the metamorphosing tadpoles exposed to the acute ΔT were more sensitive to high temperature than premetamorphic tadpoles. Finally, body mass and ΔT’s interacted on the CTmax of both species along our experimental design. In P. nattereri, body mass affected CTmax through physiology at the slow ΔT’s, whereas in H. pardalis body mass affected CTmax at the acute ΔT through a methodological artifact driven by higher thermal inertia in the group of large tadpoles. This study revealed that ΔT’s, ontogeny and body mass interact on the CTmax of our studied species, and these interactive effects could not have been elucidated by the independent study of each factor. It also highlights the importance of integrating the factors that influence thermal limits of ectothermic animals, especially in the context of climate change / Os limites térmicos para animais ectotérmicos mostram uma imagem do intervalo de temperaturas corporais que é tolerável pelos indivíduos antes de sua capacidade locomotora ser prejudicada. Porém, os limites térmicos não são características fixas e específicas, mas traços lábeis sujeitos tanto a ajustes plásticos quanto a mudanças evolutivas, e são influenciados por fatores intrínsecos e extrínsecos dos organismos, e também por fatores metodológicos associados aos protocolos experimentais. Ainda mais, as influências desses fatores sobre os limites térmicos têm sido comumente abordadas de forma independente em diferentes espécies, e o grau pelo qual múltiplos fatores interagem e afetam os limites térmicos dentro das espécies é pouco compreendido. Assim, o principal objetivo deste trabalho foi conduzir uma avaliação metodológica da Temperatura Crítica Máxima (CTmax) estudando as influências de diferentes taxas de aquecimento experimental (ΔT’s), ontogenia, massa corpórea e a interação entre esses fatores sobre esta característica fisiológica. Este assunto foi abordado em larvas de Physalaemus nattereri e Hypsiboas pardalis, dois espécies de anfíbios anuros encontrados no Estado de São Paulo, sudeste do Brasil, que diferem em sua origem filogenética, características ecológicas e de história de vida, e também habitam ambientes com diferentes regimes térmicos. Primeiro, foi encontrado que as ΔT’s afetaram tanto os valores médios quanto as variâncias da CTmax em ambas as espécies de maneira específica. Além disso, achou-se uma diminuição em CTmax no final da metamorfose que foi dependente da ΔT em larvas de P. nattereri, dado que nessa espécie só os girinos em metamorfose que foram expostos à ΔT aguda foram mais sensíveis às altas temperaturas do que os girinos premetamórficos. Finalmente, a massa corpórea e as ΔT’s interagiram sobre a CTmax em ambas as espécies ao longo do desenho experimental. Em P. nattereri, o efeito da massa corpórea sobre a CTmax foi fisiológico nas ΔT’s lentas, enquanto que em H. pardalis o efeito da massa corpórea na ΔT aguda foi devido a um artefato metodológico causado por maior inércia térmica no grupo de girinos maiores. Este estudo revelou que as ΔT’s, a ontogenia e a massa corpórea interagem sobre a CTmax das espécies estudadas, e estes efeitos interativos não poderiam ter sido elucidados pelo estudo independente de cada fator. Também é salientada a importância de integrar os fatores que influenciam os limites térmicos dos animais ectotérmicos, especialmente no contexto das mudanças climáticas
456

Development and Implementation of a Low Power Wireless Sensor Network

Bengtsson, Niclas January 2007 (has links)
The wish to measure different environmental parameters, in for example office buildings, is getting more and more important in today’s society. Since the sensors should be easily deployed they need to be battery powered and communicate wireless. Furthermore the radio range must be extended because of the limited range on the free frequencies. This is where wireless sensor networks come in and extend the range by relaying the data through other nodes in the network, thereby extending the total range of the network. The purpose of this thesis work is to develop a protocol for such a wireless sensor network, capable of delivering and relaying sensor data through the nodes of the network. The protocol has been implemented in hardware also designed in this thesis. Tests of the network have been performed and the results have shown that the network works very well and fulfills all of the requirements. Furthermore the power consumption is only 15% of the required value. This thesis has produced a very good platform to use as a base for further development of a commercial product.
457

PROTOCOL PERFORMANCE MEASUREMENT METHODOLOGY - EXPERIMENTATION WITH SIGNALING SYSTEM NO 7

Tumkur, Anand AswathaNarayana, Dutta, Avijit January 2009 (has links)
Performance is the driving force for the effective network utilization in the current telecommunication world. The thesis aims to define suitable performance measurement methodologies for communication over stack based Signalling System No 7 (SS7). This thesis also throws a quick glance on open source SS7 and Ericsson proprietary SS7 protocols, to devise performance measurement approach that can be adopted to develop sophisticated tools. We adopt a scientific experimental approach for numerical measurement of throughput and latency of the protocol stack. Our current work finishes experimentation with open source SS7 protocol (SCTP) in Fedora based two identical servers. SCTP (Stream Control Transmission Protocol) is an important transport layer protocol for communication of SS7 message over an IP network. Message communication using SCTP protocol over an IP/Ethernet network between these two identical servers has been measured and analyzed using the IPerf tool. TCP (Transmission Control Protocol) being another important transport layer protocol of TCP/IP stack, the performance of TCP is compared with SCTP. The results prove that under normal circumstances TCP gains over SCTP and our analysis support that under multi homing support, SCTP should gain over TCP when throughput is measured
458

Bridging of SCSI to SATA and Implementationof a SATA Controller using Virtex-5 / Bryggning mellan SCSI och SATA samt implementering av en styrenhet för SATA på en Virtex-5

Landström, Erik January 2009 (has links)
Companies and authorities of today often handle large amount of data, not unusually with a restricted content which should be kept secret from outsiders. One way of accomplish this is to encrypt stored data in real time. For this a hardware solution is ideal since it can be independent, fast enough, and easily added to already existing systems. This report is a starting point to achieve this with two of the most common mass storage standards SATA and SCSI in focus. It is based on the task to develop a FPGA based SATA controller and investigate the possibility to ”speak” SCSI with SATA devices. The working process has involved theoretical studies, system design, test driven development using simulations and hardware tests and technical investigation. The thesis resulted in a SCSI-to-SATA translation investigation pointing out difficulties and presenting a translation model. A SATA host was also implemented in VHDL on a Virtex-5 FPGA that can execute a number of SATA commands on different devices. Simulations performed shows that the total latency reaches one μs/32 bits in the SATA host and that should not be much of a problem for most applications in a possible bridge solution.
459

INSTRUMENTING AN ETHERNET AVIONICS BUS FOR APACHE TESTING

Cuevas, Vannesa, Diehl, Michael, Wilcox, Tab 10 1900 (has links)
Last year, the U.S. Army Yuma Proving Ground (YPG) faced a short suspense requirement to instrument an Apache's Ethernet bus. YPG was able to implement an effective method to satisfy this requirement; however, more capable and effective methodologies could not be developed and utilized due to time constraints. While continuing to support ongoing Apache testing, YPG is working to implement more efficient methods to capture and utilize the Ethernet data. This paper will discuss YPG’s initial implementation and the follow-on efforts being pursued.
460

Efficient Schemes for Improving the Performance of Clock Synchronization Protocols in Wireless Sensor Networks Using TDMA- based MAC Protocols

Watwe, Siddharth P January 2015 (has links) (PDF)
Clock synchronization in a wireless sensor network (WSN) is essential as it provides a consistent and a coherent time frame for all the nodes across the network. Typically, clock synchronization is achieved by message passing using carrier sense multiple access (CSMA) for media access. The nodes try to synchronize with each other, by sending synchronization request messages. If many nodes try to send messages simultaneously, contention-based schemes cannot efficiently avoid collisions which results in message losses and affects the synchronization accuracy. Since the nodes in a WSN have limited energy, it is required that the energy consumed by the clock synchronization protocols is as minimum as possible. This can be achieved by reducing the duration for which the clock synchronization protocols execute. Synchronous clock synchronization protocols in WSNs execute the clock synchronization process at each node, roughly during the same real-time interval, called synchronization phase. The duration when there is no synchronization activity is called the synchronization interval. Synchronization phases are divided into synchronization rounds. The energy consumed by these protocols depends on the duration of the synchronization phase and how frequently the synchronization phase is executed. Hence, to minimize the energy consumption by each node, the duration of synchronization phase should be as small as possible. Due to different drift rates of the clocks, the synchronization phases at different nodes drift apart and special techniques are required to keep them in sync. An existing protocol, called improved weighted-average based clock synchronization (IWICS) uses a pullback technique to achieve this. If a message from (i + 1)th synchronization round is received by a node still executing the ith synchronization round, the receiving node reduces its next synchronization interval to ensure greater overlap in the synchronization rounds. The reduction in overlap is a gradual and continuous phenomenon, and so, it can be detected and dealt with continuously. In this thesis, first, we make use of TDMA-based MAC protocols, instead of CSMA, to deal with the problem of message losses. We discuss the challenges of using TDMA-based MAC protocols for clock synchronization and how to overcome these challenges. Second, The IWICS protocol calculates the virtual drift rate which we use to modify the duration of the synchronization interval so that there is more overlap between the synchronization phases of neighbouring nodes. We refer to this technique as drift rate correction. Finally, we propose a different pullback technique where the pullback detection is carried out in each of the synchronization phase as opposed to the old pullback mechanism where it would be detected only when an out-of-round synchronization message is received. The proposed pullback technique when applied to the current synchronization interval ensures that the synchronization phases, that follow the current synchronization interval, are better synchronized with each other. As a result of this, we are able to reduce the duration of synchronization phases further. The IWICS protocol with all these modifications incorporated is termed as the TIWICS (TDMA-based IWICS) protocol. Simulation and experimental results confirm that the TIWICS protocol performs better in comparison to the existing protocols.

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