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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

A low power sensor positioner for satellite or balloon use

Marschke, Carl Ronald. January 1964 (has links)
Thesis (M.S.)--University of Wisconsin--Madison, 1964. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 68-69.
2

Triple modular redundancy (TMR) in a configurable fault-tolerant processor (CFTP) for space applications /

Yuan, Rong. January 2003 (has links) (PDF)
Thesis (M.S. in Electrical Engineering)--Naval Postgraduate School, December 2003. / Thesis advisor(s): Herschel H. Loomis Jr., Alan A. Ross. Includes bibliographical references (p. 259). Also available online.
3

Crew station aspects of manned spacecraft design /

Goodman, Jerry Ronald. January 1972 (has links)
Thesis (M.S.)--University of Illinois at Urbana-Champaign, 1972. / Includes bibliographical references (leaves 301-306).
4

Effects of stimulus class on short-term memory workload in complex information display formats /

Tan, Kay Chuan, January 1990 (has links)
Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 87-94). Also available via the Internet.
5

Development of a Control Moment Gyroscope controlled, three axis satellite simulator, with active balancing for the bifocal relay mirror initiative /

Kulick, Wayne J. January 2004 (has links) (PDF)
Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, Dec. 2004. / Thesis Advisor(s): Brij N. Agrawal. Includes bibliographical references (p. 103-104). Also available online.
6

Effects of stimulus class on short-term memory workload in complex information display formats

Tan, Kay Chuan 28 July 2008 (has links)
The objective of this research effort was to identify opportunities and demonstrate methods to reduce aircraft crew member cognitive workload (CWL) by reducing short-term memory (STM) demand. Two experiments qualitatively and quantitatively compared memory loading as a function of stimulus class. Experiment 1 employed a dual-task paradigm where the primary task was compensatory tracking used to load STM and the secondary task was item recognition using the Sternberg paradigm. Experiment 2 employed a singletask paradigm using a modified version of the Sternberg task. Digits, letters, colors, words, and geometrical shapes were tested as memory-set (MSET) items in the Sternberg task. Recognition latency and error rate served as objective measures of STM performance while the Subjective Workload Assessment Technique (SWAT) was employed as a Subjective second measure. Root Mean Square error was used to gauge tracking performance. Analyses of the experiments' results revealed that recognition latency and SWAT ratings Statistically varied as functions of stimulus class, MSET size, and the interaction between stimulus class and MSET size. Error rate was not statistically different across stimulus class or MSET size. Post-hoc analyses found SWAT to be a more sensitive STM measurement instrument than recognition latency or error rate. No statistically significant degree of secondary task intrusion on the tracking task was found. In addition to the commonly used classes of digits and letters, this research demonstrated that colors, words, and geometrical shapes could also be utilized as MSET items in short-term memory workload investigations. This research has, more importantly, provided further support for the vital link between STM demand and perceived workload. The main conclusion of this research is that stimulus class optimization can be a feasible method for reducing STM demand. Differences in processing rate among stimulus classes are large enough to impact visual display design. For many context-specific applications, it should be possible to determine the most efficient stimulus class in which to portray the needed information. The findings of this research are especially applicable in situations of elevated STM demand (e.g., aviation systems operations). In general, however, the results provide helpful information for visual display designers. / Ph. D.
7

Development of a Control Moment Gyroscope controlled, three axis satellite simulator, with active balancing for the bifocal relay mirror initiative

Kulick, Wayne J. 12 1900 (has links)
Approved for public release; distribution in unlimited. / This thesis develops and implements a Control Moment Gyroscope (CMG) steering law, controller and active balancing system for a three-axis satellite simulator (TASS). The CMGs are configured in a typical pyramid configuration (the fourth CMG position being null). The development was done primarily with simulation and experiments utilizing Real Time Workshop and XPC Target of MATLAB and SIMULINK. The TASS is a double circular platform mounted on a spherical air bearing with the center of rotation (CR) about the approximate physical geometric center of the simulator. The TASS utilizes three moveable masses in the three body axes for balancing which actively eliminate any center of gravity (CG) offset and return the CG to the CR. The TASS supports an optics payload designed to acquire, track and point a received laser beam onto an off-satellite target. The target may be stationary or moving. Actively balancing the TASS reduces the torque output requirement for the CMGs while maintaining either a stabilized level platform or a particular commanded attitude. Reduction or elimination of torque output from the CMGs results in a more stabilized platform, less structural induced vibration, less jitter in payload optics and less power required in spacecraft applications. / Lieutenant Commander, United States Navy
8

Modeling and Detecting Orbit Observation Errors Using Statistical Methods

Christopher Y Jang (8918840) 15 June 2020 (has links)
In the globally collaborative effort of maintaining an accurate space catalog, it is of utmost importance for ground tracking stations to provide observations which can be used to update and improve the catalog. However, each tracking station is responsible for viewing thousands of objects in a limited window of time. Limitations in sensor capabilities, human error, and other circumstances inevitably result in erroneous, or unusable, data, but when receiving information from a tracking station, it may be difficult for the end-user to determine a data set's usability. Variables in equipment, environment, and processing create uncertainties when computing the positions and orbits of the satellites. Firstly, this research provides a reference frame for what degrees of errors or biases in equipment translate to different levels of orbital errors after a least squares orbit determination. Secondly, using just an incoming data set's angle error distribution compared to the newly determined orbit, statistical distribution testing is used to determine the validity and usability of the newly received data set. In the context of orbit position uncertainty, users are then able to communicate and relay the uncertainties in the data they share while assessing incoming data for potential sources of error.
9

Utilizando as ci?ncias espaciais e a astron?utica na constru??o de atividades pr?ticas em ensino de f?sica

Machado, Jo?o Felisardo 19 May 2006 (has links)
Made available in DSpace on 2014-12-17T15:05:06Z (GMT). No. of bitstreams: 1 JoaoFelisardoM.pdf: 1390724 bytes, checksum: 3c669bea60181234ba1aa8160bc9bb5d (MD5) Previous issue date: 2006-05-19 / In this work we consider the use of new technologies fron the Space Science and Astronautical, in the learning process, incorporating technical and conceptions of physics Spatial what can take on the response of some problems what there are a lot insistent in populate the mind of professors and followers regarding agreement of these conceptions into the level Average. Intending to bring another contribution to Physics teaching practice, especially Classical Mechanics, but introducing many introductory concepts from Modern Physics, since this topic is considered of great interest for teachers and students, for it involves high technology. It s advanced manufacturing demand certain processes that make possible the application of those concepts / Neste trabalho refletimos sobre a utiliza??o das novas tecnologias provenientes das pesquisas das Ci?ncias Espaciais e da Astron?utica no processo educativo, incorporando t?cnicas e conceitos da F?sica Espacial que podem levar ? resposta de alguns problemas que h? muito insistem em povoar a mente de professores e alunos quanto ao entendimento desses conceitos no n?vel M?dio. Com ele pretendemos levar mais uma contribui??o ? pr?tica de ensino nas aulas de F?sica, especialmente da Mec?nica Cl?ssica, permeando-se, por?m, v?rios conceitos introdut?rios da F?sica Moderna, haja vista que o tema gerador ? instigante, de grande interesse por parte de mestres e aprendizes, envolvendo tecnologia de ponta, cujos componentes de fabrica??o passam por processos que possibilitam a contextualiza??o desses conceitos
10

Analise socio-tecnica de processos de produção de tecnologias intensivas em conhecimento em paises subdesenvolvidos : a trajetoria de uma empresa nuclear e espacial argentina (1970-2005) / Sociotechnical analysis of knowledge-intensive technologies production processes in underdeveloped countries: the case of an Argentinean nuclear and space company (1970-2005)

Versino, Mariana Selva 28 August 2006 (has links)
Orientador: Hernan Eduardo Thomas / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociencias / Made available in DSpace on 2018-08-07T09:01:36Z (GMT). No. of bitstreams: 1 Versino_MarianaSelva_D.pdf: 1141722 bytes, checksum: 48efd0a98f87631b89b1e0c3fa9989f4 (MD5) Previous issue date: 2006 / Resumo: A tese analisa como tem sido possível o desenvolvimento de tecnologias intensivas em conhecimento bem sucedidas em termos comerciais, em países em que existe escassa relação entre pesquisa e produção e onde o usual é a manufatura de bens com pequeno valor agregado. O estudo focaliza-se em processos concretos de criação e incorporação de conhecimentos à produção, desde uma abordagem sócio-técnica que integra as dimensões sociais, econômica, política e ideológica, analisadas de forma isolada e como ¿fatores externos¿ à produção da tecnologia na literatura existente. A pesquisa analisa as estratégias desenvolvidas pelos diferentes atores (engenheiros, pesquisadores, técnicos, empresários, clientes, fornecedores, funcionários etc.) participantes dos processos de construção de tecnologias intensivas em conhecimentos.Para isso, se estuda a trajetória sócio-técnica de uma empresa Argentina de capital nacional, exportadora de tecnologia nos setores espacial e nuclear, com uma permanência no mercado há mais de uma descada, e que baseia sua vantagem competitiva no uso intensivo do conhecimento. Utilizam-se categorias teóricas da sociologia da tecnologia e da economia da inovação, a partir de uma triangulação conceitual e de uma análise crítica para a compreensão da realidade latino-americana. A metodologia do trabalho é qualitativa e histórica. Utiliza fontes secundárias além da realização de trabalho de campo com entrevistas na empresa. A tese leva a compreender os processos de aprendizagem, produção e utilização do conhecimento em países subdesenvolvidos e ao enriquecimento das ferramentas teórico-conceituais do campo Ciência, Tecnologia e Sociedade (CTS) para a análise dos processos de mudança tecnológica e inovação na América Latina. Ao mesmo tempo, os resultados da pesquisa são um insumo de interesse para o desenho e planejamento das políticas de C&T e de inovação nacionais e regionais / Abstract: The thesis analyzes how has been possible the development of knowledge-intensive technologies comercially suscessful, in countries where there is a weak relationship between research and production and where the usual is the manufacture of goods with small joined value. The study is focused in concrete processes of criation and incorporation of knowledge to production, from a sociotechnical approach that integrates the social, economical, political and ideological dimensions considered in an isolated way and as ¿external factors¿ to the production of technology in the existent literature. The research seeks to understand the strategies developed by the different actors (engineers, researchers, technicians, entrepreneurs, customers, suppliers, employees etc.) participants of the processes of construction of knowledge-intensive technologies. For that, it is studied the sociotechnical trajectory of an Argentinean company of national capital, technology exporter in the space and nuclear sectors, with a permanence in the market of more than one decade and that bases its competitive advantage on the intensive use of knowledge. Theoretical categories of the sociology of technology and the economy of innovation are used, based on a conceptual triangulation and on a critical analysis for the understanding of the Latin-American reality. The methodology of the work is qualitative and historical. It uses secondary sources besides the accomplishment of field work with interviews in the company. The thesis intends to understand the learning processes, production and use of knowledge in underdeveloped countries and contribute to the enrichment of the theoretical tools of Science and Technology Studies (STS) for the analysis of the processes of technological change and innovation in Latin America. At the same time, the results of the research are an interesting input for the drawing and planning of Science, Technology and Innovation national policies / Doutorado / Doutor em Política Científica e Tecnológica

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