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International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / An improved ionospheric delay correction model for a transionospheric electromagnetic pulse (EMP) is used for estimating the total-electron-content (TEC) profile of the path and accurate ranging of the EMP source. For a known pair of time of arrival (TOA) measurements at two frequency channels, the ionospheric TEC information is estimated using a simple numerical technique. This TEC information is then used for computing ionospheric group delay and pulse broadening effect correction to determine the free space range. The model prediction is compared with the experimental test results. The study results show that the model predictions are in good agreement with the test results.

Thèse (M.A.)--Université Laval, 2004. / Bibliogr.: f. [169]-189. "Internet": f. 190-191. Publié aussi en version électronique.

Abstract The Technology Acceptance Model (TAM) currently enjoys the status of being the leading predictive tool for testing user acceptance of new technologies. Despite IS researchers and practitioners holding the model in high esteem, this study exposes some of its limitations when applied to a study of shop-floor users in South Africa. In search of an alternative theory explaining why these users so openly embraced the new information system, it emerges that the Critical Social Theory (CST) of Jürgen Habermas provides the most relevant insight. The use of the CST perspective reveals how these users view the new system as a potential means with which to achieve emancipation from their otherwise dreary existence as product inspectors. This thesis argues that this emancipatory potential offered by the new system played a major role in its successful acceptance. / Dissertation (Magister Commercii (Informatics))--University of Pretoria, 2007. / Informatics / unrestricted

Made available in DSpace on 2015-03-26T13:27:52Z (GMT). No. of bitstreams: 1 01 - capa_pag 43.pdf: 764272 bytes, checksum: 173aa8b0c5529105523297af4780b280 (MD5) Previous issue date: 2009-08-07 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The main source of error in the position of the user of GPS (Global Positioning System) receivers, using a frequency is the effect caused by the ionosphere on the signal transmitted by satellites. This error is directly proportional to the total electron content (TEC - Total Electron Content) in the ionosphere and inversely proportional to the square of the frequency of the transmitted signal. The TEC varies in time and space with respect to time (daily variation), the time of year (seasonal variation), geographical location, the cycle of sunspots (range, long period). In this work was studied and evaluated the variation of the TEC and, therefore, the error due to the ionosphere in the GPS observable for the years 2004 to 2008, covering the Brazilian territory, using maps of VTEC (TEC in vertical direction) using the data model global ionosphere (files IONEX - Ionosphere Map Exchange Format) from IGS (International GNSS Service) assessing the stage of the cycle of decline of 23 spots and start the cycle 24. It was also assessed the processing of precise point positioning using PPP on-line software provided by the GSD (Geodetic Survey Canada) of NRCan (Natural Resource Canada), known as CSRS-PPP (Canadian Spatial Reference System Precise Point Precise) for the years 2004 and 2008, correcting the effect of the ionosphere by IONEX. These experiments show a reduction in the value of the VTEC during 2008 in respect to the year 2004, due to lower solar activity in the year 2008 compared to 2004, consequently, a smaller amount of electrons in the ionosphere, improving the performance of the positioning with GPS, with this decline in the number of sunspots. / A principal fonte de erro na posição do usuário do sistema GPS (Global Positioning System), utilizando receptores de uma frequência, é o efeito causado pela ionosfera no sinal transmitido pelos satélites. Este erro é diretamente proporcional ao conteúdo total de elétrons (TEC Total Electron Content) presentes na ionosfera e inversamente proporcional ao quadrado da frequência do sinal transmitido. O TEC varia no tempo e no espaço com relação a hora (variação diária), a época do ano (variação sazonal), a localização geográfica, ao ciclo de manchas solares (variação de longo período). Neste trabalho foi estudado e avaliado a variação do TEC para os anos de 2004 a 2008, abrangendo o território brasileiro, através de mapas do VTEC (TEC na direção vertical) utilizando dados do modelo global da ionosfera (arquivos IONEX Ionosphere Map Exchange Format) do IGS (International GNSS Service), analisando a fase de declínio do ciclo de manchas 23 e início do ciclo 24. Também foi avaliado o processamento do posicionamento por ponto preciso, utilizando software PPP-online fornecido pelo GSD (Geodetic Survey Canada) do NRCan (Natural Resource Canada), denominado CSRS-PPP (Canadian Spatial Reference System Precise Point Precise) para os anos de 2004 e 2008, corrigindo o efeito da ionosfera pelo IONEX. Estes experimentos constatam uma redução no valor do VTEC no ano de 2008 em relação ao ano de 2004, devido a menor atividade solar no ano de 2008 em comparação à 2004, consequentemente, uma menor quantidade de elétrons presentes na ionosfera, melhorando a performance do posicionamento com GPS, com o declínio no número de manchas solares.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-03-04T10:23:09Z No. of bitstreams: 1 fernandorobertoamorimsouza.pdf: 6328191 bytes, checksum: a067c0691137d10461bb9b1d610680dd (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T01:49:26Z (GMT) No. of bitstreams: 1 fernandorobertoamorimsouza.pdf: 6328191 bytes, checksum: a067c0691137d10461bb9b1d610680dd (MD5) / Made available in DSpace on 2016-04-24T01:49:26Z (GMT). No. of bitstreams: 1 fernandorobertoamorimsouza.pdf: 6328191 bytes, checksum: a067c0691137d10461bb9b1d610680dd (MD5) Previous issue date: 2013-08-14 / A temática em estudo explora a educação profissional no Brasil, considerada atualmente matéria principal das políticas públicas do Ministério da Educação – MEC, por ser uma iniciativa que vem ao encontro do apelo midiático sobre a existência de um apagão de mão de obra no âmbito do mercado de trabalho brasileiro. Trata da Rede e-Tec Brasil, como estratégia adotada pelo governo para a qualificação de trabalhadores, constituindo-se numa ação de incentivo e apoio à oferta e expansão de cursos técnicos na modalidade a distância, que envolve instituições públicas de educação profissional e tecnológica das esferas federal e estaduais. Reflete sobre o crescimento significativo de matrículas nos cursos técnicos e o aporte orçamentário que aumenta, anualmente, e, proporcionalmente, ao número de matrículas para financiar as instituições, apontando que apesar do volumoso recurso público aplicado, não há por parte do MEC nenhuma ação de avaliação para mensurar sua eficiência de modo a garantir a eficácia desse investimento. Apresenta a sistematização de dados e informações sobre a educação profissional no Brasil, notadamente a avaliação das condições da oferta dos cursos da Rede e-Tec Brasil, contextualizada na Secretaria de Estado de Pernambuco, possibilitando levantar as potencialidades e fragilidades dos cursos, notadamente dos aspectos referentes ao processo de ensino-aprendizagem, além de subsídios para corrigir as possíveis distorções detectadas. A pesquisa permitiu um exame da realidade concreta, com a aplicação de questionários envolvendo alunos, coordenadores, tutores e professores dos cursos. Os resultados trouxeram contribuições importantes, vez que as questões abordadas envolveram diferentes componentes: cursos, polo e disciplinas onde cada avaliador trouxe informações importantes para a compreensão dos problemas investigados. A expectativa é que este estudo possa trazer contribuições significativas para elevar as condições de oferta de todos os cursos promovidos por meio da Rede e-Tec Brasil. / This study presents the systematization of data and information on vocational education in Brazil currently considered as the main theme of the policies of the Ministry of Education – MEC, as an initiative that is in agreement with the media appeal about the existence of a manpower blackout in the Brazilian labor market. This is the Brazil e-Tec Network, a strategy adopted by the government for qualifying employees, constituting an act of encouragement and support to technical courses in the distance mode expansion, which involves public institutions of professional and technological on federal and intrastate sphere. It reflects on the significant growth of enrollments in technical courses and budgetary support that increases every year, proportionally to the number of enrollments for financing institutions, indicating that despite the massive public resource applied, there is no evaluation by MEC in order to measure the strategy efficiency to ensure the effectiveness of this investment. It presents the systematization of data and information on professional education in Brazil, especially the conditions evaluation of the courses offered from Brazil e-Tec Network, contextualized in the Secretary of the State of Pernambuco, enabling the strengths and weaknesses raisings of its courses, particularly referring to the teaching and learning process as well as subsidies to remedy possible distortions detected. The research allowed an examination of the concrete reality, with questionnaires involving students, coordinators, tutors and teachers from the courses. The results brought important contributions, since the issues discussed involved different components: courses, pole and disciplines where each evaluator provided important information for the understanding of problems studied. The expectation is that this study should provide significant contributions for raising the supply conditions of all courses offered by Brazil e-Tec Network.

There is an increasing demand for higher precision when using Global Navigation Satellite Systems, GNSS, for positioning. The measurement uncertainty depends on multiple factors and one of them is the ionosphere. Due to the ionosphere being ionized and contains free electrons, satellite signals that propagates the ionosphere will be affected by the total electron content, TEC. There is no way to reduce the errors caused by the ionosphere for single frequency measuring, but it can be done for dual frequencies. The objective for this study was to compare different websites modeling results for disturbance on ground and ionospheric turbulence. Three websites were used in the comparison: Swedish SWEPOS, Norwegian seSolstorm and German IMPC. Due to different content on the websites, SWEPOS was compared with seSolstorm and IMPC was compared to seSolstorm on five different dates. In total 10 comparisons were made. The websites were evaluated on four criteria, designed from the point of view of a land surveyor: user friendliness, graphical representation, knowledge requirement and mobile website adaptation. Each criterion was graded on a scale from 1–5, where 5 was considered the best. The study showed that the modeling results from the websites differed and that the difference can not only be explained by different graphical representation or scales for measure. The results for the evaluation and grading of the websites where as follows: SWEPOS 16, seSolstorm 13 and IMPC 12. This makes SWEPOS the best suited website to use for a land surveyor. / Vid positionsbestämning finns det ett behov av högre precision vid användandet av Global Navigation Satellite Systems, GNSS. Mätosäkerheten beror av ett flertal faktorer och en av dem är jonosfären. Tack vare att jonosfären är joniserad och innehåller fria elektroner kommer satellitsignaler som färdas genom jonosfären att påverkas av det totala elektroninnehållet, TEC. Det finns idag inget sätt för enkel frekvensmätning att eliminera den mätosäkerhet som uppstår till följd av jonosfäriska störningar, däremot är det möjligt att modellera för dessa störningar då två frekvenser används. Målet för denna studie var att jämföra olika webbplatsers modelleringsresultat för störningar på marknivå och för jonosfärisk turbulens. Tre webbplatser användes i jämförelsen: svenska SWEPOS, norska seSolstorm och tyska IMPC. På grund av att hemsidorna hade olika innehåll gällande modelleringar jämfördes SWEPOS med seSolstorm, medan IMPC jämfördes med seSolstorm. Totalt gjordes 10 jämförelser för fem olika datum. Webbplatserna utvärderades utifrån fyra kriterier vilka var utformade utifrån en mätteknikers synvinkel: användarvänlighet, grafisk representation, kunskapsbehov och mobil webbplatsanpassning. Varje kriterium betygsattes på en skala från 1–5, där 5 ansågs vara det bästa. Studien visade att modelleringsresultaten från webbplatserna skilde sig åt och att skillnaden inte kunde förklaras med olika grafiska framställningar eller skalstorlek. Resultaten för utvärdering och betygsättning av webbplatserna var följande: SWEPOS 16, seSolstorm 13 och IMPC 12. Detta gjorde SWEPOS till den bäst lämpade webbplatsen att använda för en mättekniker.

The thymic stroma primarily comprises epithelial, mesenchymal and endothelial cells, interspersed with those of haematopoietic origin. Thymic epithelial cells (TECs) are highly heterogeneous, but can be divided into two broad lineages, cortical and medullary, based on phenotype, functionality and location. A population of Plet1+ TEC progenitors have been identified which, when isolated from mouse E12.5 or E15.5 fetal thymus, reaggregated, and grafted, can produce a functional thymus. However, the potential of individual progenitors to form cortex and/or medulla is undefined. The main aim of this thesis was to use retrospective clonal analysis to ascertain the point during thymus ontogeny at which the cortical and medullary lineages diverge. To this end, I used transgenic mice carrying a ubiquitous ROSA26laacZ reporter gene (where a duplication within lacZ encodes non-functional b-galactosidase). Here, rare, random laacZ-lacZ genetic recombinations result in heritable expression of functional b-gal, producing labelled clones. As this occurs at a known frequency, determination of TEC numbers would enable calculation of the expected number of TEC clones present throughout ontogeny. Due to the lack of quantitative data on all thymic cell populations, I determined the size not only of TEC (lin-EpCAM+), but also haematopoietic (CD45+), mesenchymal (lin-PDGFRa+ and/or lin-PDGFRb+) and endothelial (lin-CD31+) populations from E12.5 until E17.5. I then showed that the absolute number of Plet1+ TECs remains constant during this time, although the proportion of Plet1+ cells in cycle decreases. From these collective data, I propose a model for the role of the Plet1+ population in thymus development, in which Plet1+ cells continually give rise to Plet1- TECs in a self-renewing manner. Finally, I present a ‘dual origin coefficient’ strategy for analysis of a library of prospective TEC clones. I calculated the number of TEC lacZ+ clones expected to be present throughout thymus ontogeny, selecting an appropriate developmental stage for analysis. Although I observed several clones of apparent mesenchymal origin, supporting a single origin for intrathymic and capsular mesenchyme at E15.5, I observed no TEC clones in this extensive analysis. The CpG content of the ROSA26 promoter suggests a possibility of methylation-induced silencing brought about by de novo methylation of the lacZ reporter gene.

The purpose of this thesis has been to determine experimentally how good a peltier element is to convert waste heat from wood burning. Three different peltier elements were used in a comparison study. The comparison was mainly done to know how much power could be obtained from each element. Even, a circuit with a step-up function has been created to give a higher output voltage than the peltier element itself. The result of the experiments was a low output power, the highest value reached 2.18W. Also, the Carnot efficiency has been calculated for the three different elements and the efficiency ranged between 14 and 33%. From the circuit a constant 3.3V output was delivered. The main conclusion of this project is that furthermore Studies are needed in the material field because the elements available at the market today have too low efficiency.

abstract: Thermoelectric devices (TED's) continue to be an area of high interest in both thermal management and energy harvesting applications. Due to their compact size, reliable performance, and their ability to accomplish sub-ambient cooling, much effort is being focused on optimized methods for characterization and integration of TED's for future applications. Predictive modeling methods can only achieve accurate results with robust input physical parameters, therefore TED characterization methods are critical for future development of the field. Often times, physical properties of TED sub-components are very well known, however the "effective" properties of a TED module can be difficult to measure with certainty. The module-level properties must be included in predictive modeling, since these include electrical and thermal contact resistances which are difficult to analytically derive. A unique characterization method is proposed, which offers the ability to directly measure all device-level physical parameters required for accurate modeling. Among many other unique features, the metrology allows the capability to perform an independent validation of empirical parameters by measuring parasitic heat losses. As support for the accuracy of the measured parameters, the metrology output from an off-the-shelf TED is used in a system-level thermal model to predict and validate observed metrology temperatures. Finally, as an extension to the benefits of this metrology, it is shown that resulting data can be used to empirically validate a device-level dimensionless relationship. The output provides a powerful performance prediction tool, since all physical behavior in a performance domain is captured using a single analytical relationship and can be plotted on a singe graph. / Dissertation/Thesis / M.S. Mechanical Engineering 2011