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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.
1

Measuring the ⁷Be Neutrino Flux From the Sun: Calibration of the Borexino Solar Neutrino Detector

Hardy, Steven 06 May 2010 (has links)
The Borexino solar neutrino detector is a real-time liquid scintillator detector designed to measure sub-MeV neutrinos. With its unprecedented level of radio-purity, Borexino is poised to provide the most precise measurements to-date of solar neutrino and geo-antineutrino fluxes. However, in order to reduce the systematic errors to sub-5% levels, the detector must be care- fully calibrated to understand, among other things, the position and energy reconstructions. To that end, the Virginia Tech component of the Borexino collaboration has constructed a system for deploying and locating calibration sources within the detector. The system was used in four separate calibration campaigns and deployed numerous sources in almost 300 locations throughout the detector. The data from the calibrations have already resulted in the reduction of several sources of systematic error by a factor of two or more. With the results from the calibration, the Borexino detector has entered a new era of low- energy, high-precision, neutrino detection. This work was supported by NSF Grant 0802114 / Ph. D.
2

Desenvolvimento e análise de um índice de sustentabilidade energética utilizando lógica fuzzy

SANTOS, FRANCISCO C.B. dos 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:33Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:40Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
3

Desenvolvimento e análise de um índice de sustentabilidade energética utilizando lógica fuzzy

SANTOS, FRANCISCO C.B. dos 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:33:33Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:40Z (GMT). No. of bitstreams: 0 / A questão do Desenvolvimento Sustentável é um dos temas mais falados na atualidade, e a busca do seu entendimento um grande desafio aos pesquisadores. Mas buscar seu entendimento e as relações das dimensões que o compõe (dimensão econômica, social, ambiental e institucional) não é o único desafio. Mensurar o caminho do desenvolvimento de uma sociedade é um desafio igualmente grande, principalmente devido as intrincadas relações entre meio ambiente, sociedade e economia. Este trabalho apresenta uma nova abordagem na construção de um índice sintético de desenvolvimento sustentável do ponto de vista da sustentabilidade energética. Esta metodologia se baseou em arquétipos matemáticos estruturados na Lógica Fuzzy, permitindo assim incorporar novas bases de conhecimento, mesmo que com definições vagas. O resultado final é a criação de um Índice de Sustentabilidade Energética que pode ser acompanhado no tempo, e que permite comparações entre países, já que na sua construção utiliza-se a base de dados do Guia de Indicadores Energéticos de Desenvolvimento Sustentável da Agência Internacional de Energia Atômica, que apresenta uma metodologia mundialmente aceita de indicadores energéticos. Este índice foi concebido para se parecido com outros indicadores como Índice de Desenvolvimento Humano (IDH) elaborado pela Organização das Nações Unidas, o que permite um fácil entendimento, por ser um número entre zero e um. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
4

Development Of Free/libre And Open Source Spatial Data Analysis System Fully Coupled With Geographic Information System

Kepoglu, Volkan Osman 01 March 2011 (has links) (PDF)
Spatial Data Analysis (SDA) is relatively narrower and constitutes one of the areas of Spatial Analysis. Geographic Information System (GIS) offers a potentially valuable platform for supporting SDA techniques. Integration of SDA with GIS helps SDA to benefit from the data input, storage, retrieval, data manipulation and display capabilities of GIS. Also, GIS can benefit from SDA techniques in which the integration of these techniques can increase the analysis capabilities of GIS. This integration serves for disseminating and facilitating improved understanding of spatial phenomena. How SDA techniques should be integrated with GIS arise the coupling problem. The complete integration of SDA techniques in GIS can be applied without the support of GIS vendor when the free/libre and open source software (FLOSS) development methodology is properly followed. This approach causes to interpret the coupling problem in a new way. This thesis aims to develop a fully coupled SDA with GIS in FLOSS environment. A fully coupled SDA in free GIS software as FLOSS system is developed by writing nearly 13,000 line Python code in 2.5 years. Usage of this system has reached to nearly 1600 unique visitors, 3000 visits and 8600 page views in two years. As the current status of development in GIS is considered, it is unlikely in commercial market to have full coupled SDA techniques in GIS software. However, it is expected to have more SDA developments in proprietary GIS software in the near future as there is an increasing trend for requesting more sophisticated SDA tools.
5

Avaliação ambiental de diferentes formas de geração de energia elétrica

GUENA, ANA M. de O. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:52:35Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:39Z (GMT). No. of bitstreams: 0 / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
6

Avaliação ambiental de diferentes formas de geração de energia elétrica

GUENA, ANA M. de O. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:52:35Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:01:39Z (GMT). No. of bitstreams: 0 / No mundo moderno a energia elétrica tem um papel fundamental; ela é a base do progresso e desenvolvimento mundial. O seu surgimento propiciou a melhora no saneamento, na saúde, no abastecimento de água e alimentos, na qualidade de vida e também fez surgir a sociedade capitalista e de consumo. A utilização do petróleo como fonte geradora de energia foi o impulso da revolução industrial e através dele foram desenvolvidos motores, geradores e máquinas que contribuíram para o progresso. Com isto veio também a emissão de gases (CO2, CO, SOX e NOX) e outras substâncias que agravaram o efeito estufa, o buraco na camada de ozônio e a chuva ácida alterando o equilíbrio do planeta. O desenvolvimento de outras formas de geração de energia provocou mudanças nos locais onde estas foram instaladas, impactando o meio ambiente. Este trabalho apresenta uma avaliação ambiental sobre as diferentes formas de geração de energia elétrica e os impactos ambientais pertinentes a cada uma delas. Inclui cinco formas de geração de energia elétrica: termelétrica, nuclear, hidrelétrica, eólica e solar. No tópico energia termelétrica apresenta-se a geologia do petróleo, a sua extração e beneficiamento. Mostra também a descoberta e o desenvolvimento da indústria petrolífera no mundo e no Brasil. Detalha o funcionamento de três tipos de centrais termelétricas: a carvão, a gás e a óleo. São relacionados os impactos ambientais comuns a elas e os característicos de cada tipo de usina. Assim como o decorrente da desativação de cada uma delas. É apresentado um pequeno histórico da energia nuclear, seu desenvolvimento no Brasil e no mundo, bem como o funcionamento de uma usina e os impactos causados durante a sua operação e seu descomissionamento. A história, o funcionamento e o avanço da energia hidrelétrica no Brasil, as grandes usinas e a sua relação com o meio ambiente, são mostrados juntamente com os impactos ambientais na sua implantação, operação e desativação. A energia eólica é mostrada desde a sua implantação e funcionamento até os impactos ambientais decorrentes do processo de geração de energia elétrica e da sua desativação. No caso da energia solar é apresentado o funcionamento dos painéis solares, a implantação da central e os impactos ambientais relacionados a utilização desta. Os impactos originados na sua desativação também são apresentados. Destacados os impactos ambientais para cada forma de geração de energia elétrica, estes são correlacionados e comparados pela área de implantação da usina, a capacidade de geração, a eficiência, a potência e o custo do kW. Não existe uma forma totalmente limpa de geração de energia elétrica. Existem, sim, formas que não emitem os gases responsáveis pelo efeito estufa. Assim, todas as formas de geração de energia são importantes para um país, ou seja, quanto mais diversificada for a matriz energética, melhor. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
7

Identifying and Analyzing Knowledge Management Aspects of Practices in Open Source Software Development / Kunskapsledning i öppenkällkodsprojekt

Jonson, Fredrik, Rudzki, Przemyslaw January 2004 (has links)
In this thesis we explore how knowledge management is performed in open source projects. Open source projects are often perceived as informal, even unmanaged. Still, they appear to manage knowledge acquisition and sharing sufficiently well to successfully develop software in such a distributed environment as the Internet. This thesis aims to explore that apparent contradiction, and thus complement the currently limited research in this field. The thesis consists of a literature study of knowledge management theory and open source development, resulting in the analysis of open source practices from a knowledge management perspective. Currently the field of knowledge management maintains several, partially opposing doctrines. Apart from the business aspect, two main schools of thought are present. The commodity school approaches knowledge as a universal truth, an object that can be separated from the knower. The community school emphasises knowledge as something internal to the human mind, but which can be shared as experiences between people. In the analysis presented, we have applied an analysis method which considers both the commodity and the community perspectives. The analysis is based on previous research studies of open source, and open source practices, and is furthered by a cursory case study using examples from a selected set of open source projects. Our conclusions are that knowledge management indeed is present in open source projects, and that it is supported by an ecology like interaction of project practices. / Denna uppsats undersöker hur kunskapsledning används i öppenkällkodsprojekt. Öppenkällkodsprojekt uppfattas ofta som informella, ibland till och med okontrollerade. Ändå verkar de kunna hämta in och sprida kunskap tillräckligt väl för att kunna utveckla lyckade programvaruprojekt, även i en så distribuerad miljö som Internet. Med uppsatsen vill vi undersöka den skenbara motsättningen. Uppsatsen består av en literaturstudie av kunskapsledning och öppen källkod. Dessa studier har utmynnat i en analys av projektmetoder som används i öppenkällkodsprojekt, sett från ett kunskapsledningsperspektiv. Idag finns det flera motsägelsefulla lärosatser inom området kunskapsledning. Två huvudsakliga inriktningar är den kognitiva skolan och den konstruktivistiska skolan. I den kognitiva skolan anses kunskap kunna objektiviseras och behandlas som en vara, separat från personen som har kunskapen. Den konstruktivistiska skolan anser att kuskapen är bunden till den som vet, men att det går att dela med sig av kunskap genom social interaktion. I uppsatsen har vi analyserat projektmetoderna från båda dessa perspektiv. Analysen baseras på tidigare forskning om öppenkällkodsprojekt, och kompletteras av exempel på hur projektmetoderna används i ett urval av öppenkällkodsprojekt. Våra slutsatser är att det finns ett starkt stöd för kunskapsledning i öppenkällkodsprojekt och att den stöds av en ekologiliknande växelverkan mellan olika projektmetoder.
8

Predictive Modeling of Sulfur Flower Buckwheat (Erigonum umbellatum Torrey) Using Non-Parametric Multiplicative Regression Analysis

Davis, David B. 18 November 2009 (has links) (PDF)
Impacts of humans on ecosystems in western United States have necessitated ecological restoration, which includes the development of native seed that can be used for revegetation efforts. Development of such seed sources are costly and time consuming. This study describes the use of non-parametric multiplicative regression analysis (NPMR) to develop a predictive model for occurrence of sulfur-flower buckwheat (Eriogonum umbellatum Torrey) population seed collection. This perennial forb species is of interest for seed source development in the western United States. Presence and absence data for E. umbellatum was taken from the Utah Division of Wildlife Resources Big Game Range Trend project as well as herbarium specimens across Utah, U.S.A. NPMR, a statistical niche modeling system that selects the best predictor variables and develops probability of occurrence estimates multiplicatively, was used to select predictor variables from spatially explicit data made available in a Geographic Information System (GIS). Two models were created using NPMR, one with a suggested default minimum average neighborhood size and the other with a less-restricted minimum average neighborhood size. GIS maps of models were created, artificially classified into low, medium, and high probability areas, and validated in the field in Tooele County, Utah. Of 68 possible physiographic, climatic, and soil variables provided for analysis, NPMR selected 4 variables for the default minimum average neighborhood model and 10 variables for the less restricted neighborhood model. The default model had a higher descriptive statistic (log β value) and mapped a larger area than the less restrictive neighborhood model. When increased minimum neighborhood sizes were selected during the development of the probability maps, the resulting areas of probability prediction decreased. The presence rates of E. umbellatum in field-validated test sites were 7.4%, 12.0%, and 28.6% for the low, medium, and high probability sites, respectively. Although presence rates of field validated data were lower than the predicted probability ranges for those same sites, presence rates increased with increased probability ranges. Using the generated model can reduce the cost and time necessary to locate plants compared to searching for species populations using an undirected approach.
9

Large-scale spatially extended atmospheric pressure plasma

Cao, Zhi January 2010 (has links)
This thesis presents experimental studies of low-temperature atmospheric pressure plasma sources with generic ability to effectively treat large-scale three-dimensional (3D) objects. The reported large-scale plasma sources are developed through parallelisation of single plasma jets. This strategy outshines the other reported strategies for treatment of uneven surfaces by being able to produce spatially extended plasma directly onto the surface of heavily three-dimensional objects. Comparable studies of the design of elemental plasma jets bring out a hybrid electrode configuration, the capillary-ring jet, as the best elemental jet to be used in the parallelisation. It is found that the introduction of a ballast resistor to the individual jet circuit or built-in capacitance is important to assure the jet-to-jet synchronism, stability and uniformity. Electrical and optical analyses of one-dimensional (1D) array of atmospheric pressure plasma jets demonstrate robust temporal and spatial jet-to-jet uniformity both for flat and sloped surfaces. Hexagonally-arranged two-dimensional (2D) arrays of atmospheric pressure plasma jets show good level of insusceptibility to variations of the downstream samples in their physical dimensions as well as structural and material properties. The reaction chemistry impact area of a 2D 37-jet array is estimated to be 18.6 cm2. These confirm the plasma jet arrays as a viable option as large-scale atmospheric plasma sources, well suited for many processing applications including plasma medicine. The spatially separated dual-frequency excitation further benefits the plasma jet in that separate control of different important plasma parameters is possible. Enhanced plasma properties achieved by the dual-frequency offer greater potential to the jet arrays.
10

The Making of Laborer Subjectivity and Knowledge in the Information Industry:Gender Dimensions of Free and Open Source Development

Oh, Yeon Ju 07 August 2013 (has links)
No description available.

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