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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.
131

DEVELOPMENT OF AN UNMANNED AIRBORNE TELEMETRY TRACKING AND RELAY SYSTEM

Pho, Tam P., Wysong, Henry D. 10 1900 (has links)
ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Aerocross Systems, Inc. is developing a low-cost unmanned airborne telemetry relay system to augment the USAF Air Armament Center’s Eglin Gulf Range instrumentation resources. The system is designed to remotely autotrack and relay S-Band telemetry and VHF/UHF voice communications from test articles beyond the line-of-sight of land-based instrumentation. The system consists of a medium altitude/endurance Unmanned Aerial Vehicle (UAV), a Mission Control Station, and a remotely operated telemetry/voice tracking and relay instrumentation suite. Successfully developed and deployed, the system will contribute to lower range costs while enhancing range instrumentation performance.
132

Adaptation of a Loral ADS 100 as a Remote Ocean Buoy Maintenance System

Sharp, Kirk, Thompson, Lorraine Masi 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / The Naval Ocean Research and Development Activity (NORDA) has adapted the Loral Instrumentation Advanced Decommutation system (ADS 100) as a portable maintenance system for one of its remotely deployable buoy systems. This particular buoy system sends up to 128 channels of amplified sensor data to a centralized A/D for formatting and storage on a high density digital recorder. The resulting tapes contain serial PCM data in a format consistent with IRIG Standard 106-87. Predictable and correctable perturbations exist within the data due to the quadrature multiplexed telemetry system. The ADS 100 corrects for the perturbations of the telemetry system and provides the user with diagnostic tools to examine the stored data stream and determine the operational status of the buoy system prior to deployment.
133

ADAPTATION OF A LORAL ADS 100 AS A REMOTE OCEAN BUOY MAINTENANCE SYSTEM

Sharp, Kirk, Thompson, Lorraine Masi 11 1900 (has links)
International Telemetering Conference Proceedings / October 30-November 02, 1989 / Town & Country Hotel & Convention Center, San Diego, California / The Naval Ocean Research and Development Activity (NORDA) has adapted the Loral Instrumentation Advanced Decommutation system (ADS 100) as a portable maintenance system for one of its remotely deployable buoy systems. This particular buoy system sends up to 128 channels of amplified sensor data to a centralized A/D for formatting and storage on a high density digital recorder. The resulting tapes contain serial PCM data in a format consistent with IRIG Standard 106-87. Predictable and correctable perturbations exist within the data due to the quadrature multiplexed telemetry system. The ADS 100 corrects for the perturbations of the telemetry system and provides the user with diagnostic tools to examine the stored data stream and determine the operational status of the buoy system prior to deployment.
134

SELF-ORIENTING AND LOCATING UNIT

Briggs, James R., Youssef, Ahmed H. 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / Optical trackers are often used at the Air Force Flight Test Center (AFFTC) and at other Department of Defense (DoD) ranges to collect video and trajectory data for real-time display and postflight processing. When optical trackers are used in remote areas, pointing data from radar is utilized to enable the trackers to initially acquire targets. To enable the trackers to use radar-pointing data, offsets to true north must first be known. This offset is taken into account given the current position of the optical tracker. During postflight processing, when determining the trajectory of the target, the offsets are also taken into account to produce an accurate trajectory solution. Current methods of determining offsets to true north are time consuming and involve a lot of guesswork. Typically, a map and a known landmark are used to determine the offsets to true north. Another method is to look for the North Star (Polaris) and input an estimated offset. This paper will describe an inexpensive, stand-alone system that utilizes the Global Positioning System (GPS) to determine these offsets. This device may be modified and integrated with other systems that may need to point accurately. For example, a gun barrel on a tank may need to point accurately to within a degree. This device may also be used to accurately position telemetry antennas.
135

PERFORMANCE OF SOQPSK AND MULTI-H CPM IN THE PRESENCE OF ADJACENT CHANNEL INTERFERENCE

Hill, Terrance J. 10 1900 (has links)
International Telemetering Conference Proceedings / October 22-25, 2001 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Multi-h CPM has been selected as the Tier II waveform for the Advanced Range Telemetry (ARTM) program, because it offers 50% better spectral efficiency than Feher-patented FQPSK, which is the Tier I waveform. Shaped Offset QPSK has been shown to be nearly identical in performance to Feher-patented FQPSK. Both the Tier I and Tier II waveforms must operate in the presence of adjacent channel interference in order to meet the range community's telemetry requirements. This paper presents an experimental characterization of SOQPSK and Multi-h CPM in the presence of adjacent channel interference, over a range of channel spacings and differential signal amplitudes. Quantitative results are presented which demonstrate the relative robustness of the ARTM Tier I and Tier II waveforms, with adjacent channel interference representative of a typical range environment.
136

Real-Time Calibration of the Steering Wheel Angle Sensor

Larsén, Nils January 2017 (has links)
A stationary or temporary offset in the steering system of a vehicle can result in functions, relying on the steering wheel angle, performing poorly. Due to the wide range of different vehicle configurations at Scania CV, all sensors with relevant information regarding vehicle direction are not available on all vehicles. By using a statistical approach, including common sensors installed on the vehicle, a conceptual algorithm calibrating the Steering Wheel Angle Sensor offset in real- time has been developed. The algorithm is simple and relies on the assumption that a vehicle is driving straight ahead most of the time above a certain minimum vehicle speed, thus the most frequent steering wheel angle is the straight ahead angle. The algorithm is only active above the certain minimum vehicle speed and consists of two moving windows comprising steering wheel angle samples in which the calculations are performed. The results show that the algorithm is able to detect offsets with a short calibration time. Storage of samples is required but no vehicle specific parameters are needed.
137

Technology Transfer within Related Offset Business : From an Aircraft Production Perspective

Malm, Anna January 2016 (has links)
The aircraft industry is viewed as a prestigious industry by many countries. Emerging economies regard the establishment of aircraft production capabilities as contributing to their competitiveness and technological development. Therefore, in the defence aircraft industry, politics play a key role in competitiveness. Governments can strategically trade market access for technological development, often in the form of offset business. “Offset” is defined as an agreement in which a large system is bought and the seller assumes obligations that both benefit the buying nation and have long-term effects on the development of the buyer’s national industry. When the offset obligations are directly connected to the product or system sold, they are called “related offsets”. The realization of an offset agreement is in most cases including some form of technology transfer. Technology transfer is the transfer of technology from a sending company, to a receiving company, where it is implemented and adapted to use. The empirical data presented in this thesis were gathered through six in-depth studies performed at the unit for aircraft production at the Swedish company Saab. The findings from the studies are presented in six appended papers. The objective of this thesis is to extend the current understanding of technology transfer realization connected to related offsets within the defence aircraft industry. The research objective is fulfilled through the addressing of two research questions. The first research question aims to identify factors that can have a major effect on technology transfer realization in the research context. As an answer to the first research question. Following factors were identified: Capability gaps, Knowledge transfer, The purpose of related offset business, Seller’s fulfilment of offset obligations before contract termination, Related offset business include hierarchical levels, Related offset work package identification to meet the buyer’s request, and Assessment of the receiver in two steps, and finally Cultural and communication challenges. These factors set the basis for research question two. The second research question addresses how to manage future related offset technology transfer realization connected to aircraft production. As an answer to the second research question, a structured related offset process and facilitation tools for managing capability gaps between the sending and the receiving company was presented. The purpose of the suggested structure is to maintain the link between the negotiated related offset agreements and the employees, working to achieve the agreement within the realization of the technology transfer.
138

Assessing the performance of Ecological Compensation in Sweden : A comparative case study of an emerging tool in different contexts

Kylin, Hanna Linnéa January 2017 (has links)
The concept of ecological compensation (EC) assumes that ecological values are substitutable across spatial units. EC is increasingly recognised in Sweden as a novel policy instrument for land-use planning, however, it suffers from inconsistency in application and outcome. For example, there are no legal provisions to require EC for urban development or new roads and railways. This study shows that there are many context dependent variables affecting the performance of EC in Sweden, which can partly be explained by authorities’ lacking experience in administrating these questions, and by the absence of a standardised structure for handling the full EC process. These shortcomings together with an inadequate legislation may cause EC to result in “license-to-trash” and fails to guarantee no net loss of ecological values. The performance of EC in Sweden was assessed through two case studies: the Sigtuna trading estate and the Aitik mine expansions. Implementation procedures and compensation designs were investigated by analysis of written documents and semi-structured interviews. The data was structured in an analytical framework, displaying similarities and context dependent disparities. The results suggest that, for the Aitik-case, licence-to-trash is a risk if compensation schemes are reviewed by the regulatory authorities during the processing of the application. The Sigtuna case suggests, opposed to earlier findings, that the Plan and Building Act can be utilised for EC if the compensation measures are regulated in a development agreement between the municipality and the landowner/developer. Both cases suggest that additionality can be met by appropriate institutional design, whereas no net loss of biodiversity and ecosystem services hardly can be achieved within the existing Swedish legal framework. To improve the performance of EC, structures for handling the process from quantification of social and ecological values, to monitoring of compensation outcomes must be implemented in all development projects affecting nature.
139

Acordos de Compensação (Offsets) na Força Aérea: uma análise do Projeto H-X BR

Silva, Robson Alves da January 2016 (has links)
Submitted by Fernanda Weschenfelder (fernanda.weschenfelder@uniceub.br) on 2018-05-28T18:43:17Z No. of bitstreams: 1 61300067.pdf: 1248300 bytes, checksum: 9d3f40fb51f674713bd598e87a9ae2a5 (MD5) / Approved for entry into archive by Fernanda Weschenfelder (fernanda.weschenfelder@uniceub.br) on 2018-05-28T18:43:22Z (GMT) No. of bitstreams: 1 61300067.pdf: 1248300 bytes, checksum: 9d3f40fb51f674713bd598e87a9ae2a5 (MD5) / Made available in DSpace on 2018-05-28T18:43:22Z (GMT). No. of bitstreams: 1 61300067.pdf: 1248300 bytes, checksum: 9d3f40fb51f674713bd598e87a9ae2a5 (MD5) Previous issue date: 2016 / A presente pesquisa teve como meta avaliar criticamente em que medida os Acordos de Offset contribuem para o desenvolvimento da indústria de defesa, na perspectiva do setor aeronáutico brasileiro. Buscou-se analisar o processo de transferência de tecnologia, a partir dos acordos de compensação firmados no Projeto H-X BR, cujo objeto é a aquisição de 50 helicópteros franceses e suporte logístico inicial, destinados à satisfação de demandas operacionais das três Forças Armadas. A presente pesquisa analisou também as contribuições teóricas das principais linhas de pensamento em relação ao papel da inovação para o segmento de defesa, levando-se em conta os múltiplos participantes da estrutura estatal, a análise do arranjo normativo brasileiro e a natureza jurídica das práticas compensatórias, bem como o papel dos atores envolvidos no processo de aprovação dos Acordos de Offset.
140

Cálculos de estrutura eletrônica de materiais e nanoestruturas com inclusão de autoenergia: Método LDA - 1/2. / Electronic structure calculations of material and nanostructures with the inclusion of the self-energy: the LDA - 1/2 method.

Ribeiro Junior, Mauro Fernando Soares 13 December 2011 (has links)
Neste trabalho, utilizamos o desenvolvimento recente do método DFT/LDA-1/2 para cálculos de estados excitados em materiais. Começamos com um resumo da teoria do funcional da densidade (DFT) e incluímos uma introdução ao método LDA-1/2 para cálculos de excitações em sólidos. Na compilação dos resultados esperamos ter demonstrado a utilidade do LDA-1/2 para cálculos de alinhamentos de bandas em junções semicondutor/semicondutor e semicondutor/isolante. A aplicação do método envolve o conhecimento da química básica dos sistemas. Para tanto, escolhemos sistemas importantes para diversas aplicações, e cujos modelos de simulação estão o limite ou fora do alcance de metodologias que envolvem alto custo computacional, mas que foram bem caracterizados experimentalmente. Concentramos nossas ações no estudo da capacidade preditiva do LDA-1/2 para alinhamentos de bandas, os chamados band offsets, particularmente importantes para a micro e optoeletrônica. Quando não foi possível compararmos nossos resultados com o experimento, procuramos a comparação com métodos estado-da-arte como GW. Bons resultados foram obtidos para band gaps e band offsets de interfaces A1As/GaAs, Si/SiO2, A1N/GaN e CdSe/CdTe, que representam os diferentes tipos de jun_c~oes poss__veis, com (e.g. A1As/GaAs, A1N/GaN) e sem (e.g. Si/SiO2, CdSe/CdTe) ^anions omuns, com (e.g. A1As/GaAs) e sem (e.g. CdSe/CdTe, Si/SiO2) casamento de parâmetros de rede e diferentes tipos de alinhamentos (\"straddling\", e.g. A1As/GaAs ou \"staggered\"e.g. CdSe/CdTe). Analisamos de maneira sistemática o comportamento do entorno do bandgap ao longo da interface, verificando plano a plano atômico o comportamento das bordas de valência e condução com LDA-1/2 em comparação com o LDA, ou comparando diferentes modelos dentro do LDA-1/2, como o caso do CdSe/CdTe e do Si/SiO2. Para o caso A1As/GaAs, aproveitamos o casamento de parâmetros de rede dos semicondutores constituintes e tentamos um modelo de interface de ligas A1xGa1-x As/GaAs para estudar a variação de valência, condução e bandgap em função da composição x. No AlN/GaN, estudamos também os offsets com as contribuições dos orbitais separadamente. Em todos os casos o LDA-1/2 levou-nos a resultados interessantes com modelos simples. A exploração de novas fronteiras de aplicação do método fez-se necessária com a diminuição da dimensionalidade dos sistemas, de 3D (bulk ) para 2D (interfaces) e depois para 1D, ou seja, _os quânticos (\"nanofios\"). Nosso material de estudo para os foi o ZnO que, além da motivação oriunda de conhecidas aplicações em optoeletrônica, apresenta desafios para simulações bulk com qualquer método, e que foi abordado com certo sucesso usando o LDA-1/2 anteriormente, sendo que para fios quânticos encontramos resultados interessantes em geometrias triangulares que facilitaram os modelos. Calculamos o bandgap ZnO bulk e de nanofios passivados e não passivados com hidrogênios usando LDA e LDA-1/2 sem polarização de spin. As estruturas de bandas e o bandgap como função do diâmetro do ano_o foram calculados e ajustes com funções de decaimento foram feitos para comparação, por extrapolação, dos bandgaps com valores experimentais. Foi possível comparar nossos resultados de fios com o bulk, e predizer uma faixa de variaação de bandgaps que os experimentais podem encontrar para nanofios triangulares de ZnO. Também foi feita análise de energias de confinamento em fios quânticos de ZnO, comparando o LDA com LDA-1/2. Finalmente, mostramos os resultados de uma oportunidade de aplicação do método a um material com defeitos, recentemente descoberto e promissor, e com enorme mercado potencial em fotocatálise, o Ti1-O4N. Nosso trabalho envolveu a aplicação do LDA-1/2 a um problema muito desafiador, e.g. a geração de energia limpa, especificamente a separação da molécula de água para produção de hidrogênio. O desafio maior vem da dificuldade de predição de bandgaps teoricamente, em particular para sistemas grandes como é o caso de modelos atomísticos com defeitos, devido aos altos custos computacionais envolvidos. Tais dificuldades forçam os pesquisadores a usarem parâmetros ajustáveis ou métodos semi-empíricos, ou modelos simplificados demais para descrever precisamente resultados experimentais. Isto dificulta o estudo dos sistemas fotocatalíticos potencialmente eficientes e que não foram ainda caracterizados ou otimizados. O LDA-1/2 é aqui validado para esta classe de materiais, abrindo assim a oportunidade para estudar sistemas mais realísticos e complexos para cálculos ainda mais precisos, particularmente para geração de energia limpa. Em particular, modelamos o TiO2 na estrutura rutile com nitrogênio substitucional, cuja estrutura eletrônica é ainda debatida. Foi a primeira aplicação do LDA-1/2 a sistemas com algum tipo de defeito, com ótimos resultados para o novo sistema Ti1- _O4N com vacâncias de Ti. / In this work, we used the recent development of DFT/LDA-1/2 method for calculations of excited states in materials. We begin with a summary of the density functional theory (DFT) and included an introduction to the method LDA-1/2 for calculations of excitations in solids. In compiling the results we hope to have demonstrated the usefulness of the LDA-1/2 for calculating alignments of bands at junctions semiconductor / semiconductor and semiconductor / insulator. The method involves the knowledge of basic chemical systems. To do this we chose systems important for several applications, and simulation models which are the limit or beyond the reach of methodologies involving high computational cost, but have been well characterized experimentally. We focus our actions in the study of the predictive capability of the LDA-1/2 for alignments of bands, the band called offsets, particularly important for micro and optoelectronics. When it was not possible to compare our results with experiment, we compared the methods with state of the art as GW. Good results were obtained for band gaps and band offsets of interfaces A1As/GaAs, Si/SiO2, A1N/GaN and CdSe / CdTe, which represent the different types of jun_c poss__veis-tions, with (eg A1As/GaAs, A1N/GaN) and without (eg Si/SiO2, CdSe / CdTe) ^ omuns anions with (eg A1As/GaAs) and without (eg CdSe / CdTe, Si/SiO2) matching network parameters and different types of alignments (\"straddling\" eg A1As/GaAs or \"staggered\" eg CdSe / CdTe). Systematically analyze the behavior of the environment along the interface bandgap, plane by plane scanning behavior of the edges atomic valence and conduction with LDA-half in comparison with LDA, or comparing templates within the LDA-1 / 2, as the case of CdSe / CdTe and Si/SiO2. For the case A1As/GaAs, we take the marriage of network parameters of semiconductor components and try an interface model alloys A1xGa1-x As / GaAs to study the variation of valence, conduction and bandgap as a function of composition x. In the AlN / GaN, we also studied the offsets with the contributions of the orbitals separately. In all cases the LDA-half led us to interesting results from simple models. The exploration of new frontiers of the method was necessary to decrease the dimensionality of the systems, the 3D (bulk) for 2D (interfaces) and then to 1D, ie, quantum _os (\"nanowires\"). Our study material for the ZnO was that, apart from the motivation coming from known applications in optoelectronics, presents challenges for bulk simulations with any method, and that was addressed with some success using the LDA-half earlier, and for wireless find interesting results in quantum triangular geometries that facilitated models. We calculate the bandgap and bulk ZnO nanowires passivated and not passivated with hydrogen using LDA and LDA-1/2 without spin polarization. The bandgap structures and strips as a function of the diameter of ano_o adjustments are calculated and decay functions for comparison were made by extrapolation of the bandgaps with experimental values. It was possible to compare our results with the bulk of wires, and predict a range of bandgaps that variaação can find experimental triangular ZnO nanowires. It was also made analysis of energy confinement in ZnO quantum wires, comparing LDA with LDA-1/2. Finally, we show the results of an opportunity to apply the method to a material with defects, newly discovered and promising, and with huge market potential in photocatalysis, the Ti1-O4N. Our work involved the application of LDA-1/2 to a very challenging problem, eg the generation of clean energy, specifically the separation of the water molecule for hydrogen production. The main challenge has been the difficulty of predicting bandgaps theoretically, in particular for large systems such as the model atomistic defects because of the high computational costs involved. These difficulties force the researchers to use adjustable parameters or semi-empirical methods, or other simplified models to accurately describe experimental results. This complicates the study of potentially efficient photocatalytic systems which have not yet been characterized or optimized. The LDA-1/2 is here validated for this class of materials, thus opening the opportunity to study more realistic and complex systems for more accurate calculations, particularly for clean energy generation. In particular, we modeled the structure of TiO2 in the rutile with substitutional nitrogen, whose electronic structure is still debated. It was the first application of the LDA-1/2 systems with some kind of defect, with excellent results for the new system Ti1-_O4N with Ti vacancies.

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