Дисертації з теми "Fin array"
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Cowan, Jonathan B. "Investigation of Erosion and Deposition of Sand Particles within a Pin Fin Array." Thesis, Virginia Tech, 2009. http://hdl.handle.net/10919/35959.
Повний текст джерелаMaster of Science
Harding, Matthew T. "An experimental investigation of the performance of staggered PIN-FIN Array laminar flow heat exchangers." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Mar%5FHarding.pdf.
Повний текст джерелаKomral, Ata. "Heat transfer studies and flow visualization of a rectangular channel with an offset strip fin array." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1995. http://handle.dtic.mil/100.2/ADA306675.
Повний текст джерелаThesis advisor(s): Matthew Kelleher. "September 1995." Includes bibliographical references. Also available online.
Suarez, Carlos M. "Heat transfer studies and flow visualization of a rectangular channel with an offset-plate-fin array." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1996. http://handle.dtic.mil/100.2/ADA311664.
Повний текст джерелаFarjam, Aslan. "Influence of Alumina Addition to Aluminum Fins for Compact Heat Exchangers Produced by Cold Spray Additive Manufacturing." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/33383.
Повний текст джерелаTindall, A. T. R. "Experimental and theoretical studies of convective heat transfer from fin arrays." Thesis, University of Lincoln, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.354881.
Повний текст джерелаThrift, Alan Albright. "Aerodynamic Force and Pressure Loss Measurements on Low Aspect Ratio Pin Fin Arrays." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/31189.
Повний текст джерелаThis project culminates in the measurement of both pin fin force and array pressure drop as they related to changes in the array geometry. Specifically, the effects of Reynolds number, spanwise pin spacing, streamwise pin spacing, pin aspect ratio, and flow incidence angle. Direct two-component force measurement is achieved with a cantilever beam force sensor that uses highly sensitive piezoresistive strain gauges, relating the strain at the base of the beam to the applied force. With proper characterization, forces as small as one-tenth the weight of a paper clip are successfully measured. Additionally, array pressure drop measurements are achieved using static pressure taps.
Experiments were conducted over a range of Reynolds numbers between 7,500 and 35,000. Changes in the spanwise pin spacing were shown to substantially alter the pin fin drag and array pressure drop, while changes in the streamwise pin spacing were less influential. The experimental results also showed a dramatic reduction in the pin fin drag and array pressure drop for an inline flow incidence angle. Finally, changes in the pin aspect ratio were shown to have little effect on the array pressure drop.
Master of Science
Esposito, Robert Anthony. "TURBO CODING IMPLEMENTED IN A FINE GRAINED PROGRAMABLE GATE ARRAY ARCHITECTURE." Diss., Temple University Libraries, 2009. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/26071.
Повний текст джерелаPh.D.
One recent method to approach the capacity of a channel is Turbo Coding. However, a major concern with the implementation of a Turbo Code is the overall complexity and real-time throughput of the digital hardware system. The salient design problem of Turbo Coding is the iterative decoder, which must perform calculations over all possible states of the trellis. Complex computations such as exponentiations, logarithms and division are explored as part of this research to compare the complexity of the traditionally avoided maximum a-posteriori probability (MAP) decoder to that of the more widely accepted and simplified Logarithm based MAP decoder (LOG-MAP). This research considers the fine grained implementation and processing of MAP, LOG-MAP and a hybrid LOG-MAP-Log Likelihood Ratio (LLR) based Turbo Codes on a Xilinx Virtex 4 PGA. Verification of the Turbo Coding system performance is demonstrated on a Xilinx Virtex 4 ML402SX evaluation board with the EDA of the Xilinx System Generator utilizing hardware co-simulation. System throughput and bit error rate (BER) are the performance metrics that are evaluated as part of this research. An efficient system throughput is predicated by the parallel design of the decoder and BER is determined by data frame size, data word length and the number of decoding iterations. Furthermore, traditional and innovative stopping rules are evaluated as part of this research to facilitate the number of iterations required during decoding.
Temple University--Theses
Axtmann, Meriam [Verfasser]. "Investigations on Heat Transfer and Pressure Loss in Staggered Pin Fin Cooling Arrays / Meriam Axtmann." München : Verlag Dr. Hut, 2018. http://d-nb.info/1164293982/34.
Повний текст джерелаMoores, Kevin A. "Effect of tip clearance on the thermal and hydrodynamic performance of shrouded pin fin arrays." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8787.
Повний текст джерелаThesis research directed by: Dept. of Mechanical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Achanta, Vamsee Satish. "An experimental study of endwall heat transfer enhancement for flow past staggered non-conducting pin fin arrays." [College Station, Tex. : Texas A&M University, 2003. http://hdl.handle.net/1969.1/140.
Повний текст джерела"Major Subject: Mechanical Engineering" Title from author supplied metadata (record created on Jul. 18, 2005.) Vita. Abstract. Includes bibliographical references.
Dallmeyer, Matthew John. "Reducing Fir Filter Costs: A Review of Approaches as Applied to Massive Fir Filter Arrays." University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1417544448.
Повний текст джерелаWalsh, Declan. "Design and implementation of massively parallel fine-grained processor arrays." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/design-and-implementation-of-massively-parallel-finegrained-processor-arrays(e0e03bd5-4feb-4d66-8d4b-0e057684e498).html.
Повний текст джерелаLico, Rocco <1984>. "Non-thermal emission in High Frequency Peaked blazars towards the Square Kilometer Array era." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amsdottorato.unibo.it/7233/.
Повний текст джерелаRodney, David M. "Digital Channelized Wide Band Receiver Implemented with a Systolic Array of Multi-Rate FIR Filters." Wright State University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=wright1150923373.
Повний текст джерелаMarinho, Marco Antonio Marques. "Array interpolation methods with applications in wireless sensor networks and global positioning systems." reponame:Repositório Institucional da UnB, 2013. http://repositorio.unb.br/handle/10482/15614.
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Nas últimas três décadas o estudo de técnicas de processamento de sinais em arranjos de sensores tem recebido grande atenção. Uma grande quantidade de técnicas foi desenvolvida com diversas finalidades como a estimação da direção de chegada, a filtragem ou separação espacial dos sinais recebidos, a estimação do atraso de propagação, a estimação da frequência Doppler e a pré-codificação de sinais na transmissão para maximização da potência recebida por outro arranjo. Técnicas para estimação da direção de chegada são de particular interesse para sistemas de posicionamento baseado em ondas de rádio, como os sistemas de posicionamento global e para o mapeamento de sensores em redes de sensores. Uma particularidade dessas aplicações é a necessidade de uma estimação em tempo real ou computacionalmente eficiente. Técnicas de estimação da direção de chegada que atendem esses requisitos requerem uma estrutura muito específica do arranjo de antenas que, em geral, não pode ser obtida em implementações reais. Nesse trabalho é apresentado um conjunto de técnicas que permitem a interpolação de sinais recebidos em arranjos de geometria arbitrária para arranjos de geometria específica, de forma eficiente e robusta, para possibilitar a aplicação de técnicas eficientes para estimação da direção de chegada em arranjos de geometria arbitrária. Como aplicações das técnicas propostas são apresentados o mapeamento preciso em redes de sensores e posicionamento preciso em receptores de sistemas de posicionamento global. _______________________________________________________________________________________ ABSTRACT
In the last three decades the study of antenna array signal processing techniques has received significant attention. A large number of techniques have been developed with different purposes such as the estimation of the direction of arrival (DOA), filtering or spatial separation of received signals, estimation of time delay of arrival (TDOA), Doppler frequency estimation and precoding of transmitted signals to maximize the power received by a different array. DOA estimation techniques are of particular interest for positioning systems based on radio waves such as the global positioning system (GPS) and for sensor mapping in wireless sensor networks (WSNs). These applications have the particular requirement of demanding the estimations to be made in real time or with reduced computational complexity. DOA estimation techniques that fulfill these requirements demand very specific antenna array structures that cannot, in general, be obtained in real implementations. In this work a set of techniques is presented that allows the interpolation of signals received in arrays of arbitrary geometry into arrays of specific geometry efficiently and robustly to allow the application of efficient DOA estimation techniques in arrays of arbitrary geometry. As an application of the proposed techniques precise mapping for WSNs and precise positioning for GPS receivers is presented.
Burich, Lawrence D. "Digital Wideband Spectral Sensing Receiver." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1345689526.
Повний текст джерелаRosette, Keith Andrew. "Investigation of a compact acoustic source array for the active control of aircraft engine fan noise." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-12302008-063020/.
Повний текст джерелаPotluri, Keerti. "Improving DNA quality using FFPE tissues for Array Comparative Genomic Hybridization to find Single Nucleotide Polymorphisms (SNPs) in Melanoma." Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1438267267.
Повний текст джерелаLawson, Seth Augustus. "Heat Transfer from Multiple Row Arrays of Low Aspect Ratio Pin Fins." Thesis, Virginia Tech, 2007. http://hdl.handle.net/10919/31190.
Повний текст джерелаMaster of Science
Santamaria, Luca. "Systèmes d'antennes reconfigurables intégrés dédiés aux réseaux IoT sans fil dynamiques." Thesis, Université Côte d'Azur, 2021. http://www.theses.fr/2021COAZ4103.
Повний текст джерелаBecause of the unique characteristics of the Internet of things (IoT), such as massive volume of data, stringent resource constraints, and heterogeneous activity levels, future wireless IoT infrastructures must integrate smart self-organizing solutions to efficiently operate in the dynamic IoT environment.Within this context, this thesis presents the development of innovative integrated reconfigurable antenna systems capable of adapting to such dynamic and multi-purposed wireless IoT networks.As a first step, the thesis covers the design of antennas suitable for integration in IoT terminals when specific radiation properties or multi-band operations are needed. Both antenna structures and integration techniques are presented for single and multi-band IoT applications. Next, a design methodology based on a multi-access single structure antenna and a miniaturized omnidirectional circularly polarized antenna for IoT applications are presented. Successively, an approach based on Neural Networks (NN) to estimate the performance of small antennas given practical constraints is presented. As proof of concept, the case of printed antennas integrated into compact terminals is considered.In the second part, the thesis focuses on the development of compact and low-power-consuming reconfigurable antennas. In order to enable new applications, such as wearable communications, and to deliver higher performance in a variety of integration environments, a flexible, reconfigurable antenna is presented. To guarantee reliable operation, flexible antennas must maintain proper electrical or radiation characteristics despite the variation of their structure given by the flexibility. Consequently, the reconfiguration mechanism of the proposed antenna allows the shift of the antenna resonance, making the antenna capable of maintaining an acceptable impedance matching over the operating band even when the antenna is folded.A compact high gain and front-to-back ratio pattern reconfigurable antenna for spatial filtering in IoT networks is then proposed. The reconfiguration mechanism is based on the use of a low-insertion, low-on resistance SP4T switch, which can be numerically controlled by a microcontroller, as required by IoT applications. Successively, a slot-based electronically steerable parasitic array radiator (ESPAR) antenna suitable for IoT applications is presented. The work describes in-depth the design procedure of the antenna, addressing the practical implementation of the reconfiguration mechanism, and focusing on the realization of the prototype and its experimental evaluation.Finally, a methodology for synthesizing parasitic antenna arrays is proposed. The method is based on the use of a Particle Swarm Optimizer (PSO), which iteratively optimizes the parasitic element loads until the desired pattern behavior is obtained. In order to assess the method's ability to address the desired goals, the methodology is used to optimize the directivity, the front-to-back ratio, and the gain of compact parasitic array antennas for IoT devices. The impedance loads values identified with this approach are integrated into the antenna structures to realize the parasitic antenna array. Reconfiguration can then simply be obtained by rotating the load's values over the parasitic elements
Conradie, P. J. F. "Edge fan performance in air cooled condensers systems." Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4238.
Повний текст джерелаENGLISH ABSTRACT: Large air‐cooled heat exchangers and condensers make use of fan arrays to provide cooling. The performance of the fan arrays are however negatively affected by distorted inlet conditions. Given the size of these fans, quantifying exactly what the detrimental effects are is practically impossible. This serves as motivation for developing a scaled multi‐fan testing platform that is able to mimic the behaviour of a full‐scale array but at a more measureable and manageable scale. This investigation was conducted in two parts. A Reynolds number investigation was conducted to determine what effect incorporating Reynolds number effects will have on the scaled fan performance. Computational fluid dynamics (CFD) was used to determine where turbulent transition onset occurs on the full‐scale fan blades and trip wires were then sized and positioned appropriately to recreate the same transition effect. From this initial investigation it was found that the trip wires have an allround negative impact on fan performance but when compensated for by increasing the blade angle, the tripped fan static pressure rise performance is comparable with the non‐tripped fan performance. This suggests that the Reynolds number effects may be ignored for this scaled fan testing investigation. Scaled equivalents of the fans in cooling arrays were tested in a three row multi‐fan array which, using symmetry, represents a typical bay in a full‐scale installation. Various platform heights were simulated and the corresponding decrease in system performance was compared to a model formulated to predict how fan volumetric effectiveness decreases with platform height. The model deviated from the test data at very low platforms heights. A replacement fan for the scaled equivalent fan was tested while installed as the edge fan of a multi‐fan array, the fan worst affected by any inlet disturbance, and was found to perform similarly to the scaled equivalent fan for most platform heights but exceeded the scaled equivalent fan’s performance for the lowest platform height and the most adverse conditions. This proves the effectiveness of the replacement fan as an edge fan.
AFRIKAANSE OPSOMMING: Groot lugverkoelde warmteruilers maak gebruik van waaier matrikse om verkoeling te voorsien. Die verrigting van die waaieropstelling word egter negatief beïnvloed deur versteurde inlaattoestande. Gegewe die grootte van hierdie waaiers is daar geen praktiese metode om die nadelige invloed van die versteurde inlaattoestande te kwantifiseer nie. Hierdie dien as motivering vir die ontwikkeling van ‘n multi‐waaier toetsplatform wat daartoe in staat is om die gedrag van die volskaal opstelling na te boots maar op ‘n baie meer meetbare en hanteerbare skaal. Hierdie ondersoek was uitgevoer in twee dele. ‘n Reynoldsgetal ondersoek was uitgevoer om te bepaal watter impak dit sal hê op die skaalwaaier verrigting indien die Reynolds getaleffekte ingesluit word in die toetswerk. Berekende vloeidinamka (BVD) was gebruik om te bepaal waar turbulente oorgang voorkom op die volskaal waaierlemme en pooitjiedrade was geselekteer en geposisioneer hiervolgens om dieselfde oorgang te herskep. Vanuit hierdie aanvanklike ondersoek was dit gevind dat die pooitjiedrade ‘n algehele afname in verrigting tot gevolg het, maar wanneer dit oorkom word deur die lemhoek op te stel, die gedrag en verrigting van die gepooitjiede waaier soortgelyk is aan die van die nie‐gepooitjiede waaier. Hierdie gedrag stel voor dat die Reynoldsgetalle maar geïgnoreer kan word vir hierdie skaalwaaier toetswerk. Gelykwaardige skaalwaaiers van die wat in bedryf is in volskaal opstellings was getoets in ‘n drie ry multi‐waaier opstelling wat, deur simmetrie, verteenwordigend is van ‘n tipiese straat in ‘n volskaal opstelling. Verskeie platformhoogtes was gesimuleer en die ooreenstemmende afname in stelsel verrigting was vergelyk met ‘n model wat geformuleer is juis om te voorspel hoe die volumetriese effektiwiteit afneem met platformhoogte. Die model wyk af van die toetsdata by baie lae platform hoogtes. ‘n Vervangingswaaier vir die aanvanklike geskalleerde waaier was getoets as ‘n randwaaier, die waaier wat die ergste benadeel word deur versteurde inlaattoetstande, in die multi‐waaier opstelling. Die vervangingswaaier het soortgelyk aan die aanvanklike waaier verrig vir meeste platformhoogtes, maar oortref die aanvanklike waaier se werksverrigting by die laagste platformhoogte en mees ongunstige toestande. Hierdie bewys die vermoëns van die vervangingswaaier as ‘n randwaaier.
Rust, Ryan Leonard. "Active Noise Control of a Two-Fan Exhaust-Mounted Array Using Near-Field Control Sources and Error Sensors." BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2427.
Повний текст джерелаSouza, Gustavo Souto de Sá e. "Arranjo linear de dez eletrodos ativos sem fio para eletromiografia de superfície." Universidade Federal de Goiás, 2013. http://repositorio.bc.ufg.br/tede/handle/tede/3895.
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This project, in the area of biomedical engineering, belongs to the promising field of research in surface electromyography (s-EMG). This technology can be used for in-depth study of some neuromuscular diseases, such as polyneuropathies and myopathies. Using an array of multichannel electrodes, we can also obtain the decomposition of s-EMG signals, estimation of conduction velocity of muscle fibers, location of innervation zones (set of motor units), among other applications. Although there are wireless electromyographers, there are no wireless electrode arrays in the market. Thinking about this, it was developed a wireless linear array of ten active electrodes for surface electromyography and a set of programs able to receive and process the data captured by this device. The hardware’s features are: low cost compared to similar equipment on the market, 12 bits resolution, 9216 samples per second (1024 samples per second per channel, with 9 channels and 10 electrodes in bipolar configuration), common mode rejection ratio greater than 50 dB; possess an interface for easy interaction with any computers via Bluetooth; enabling research in diverse areas (biomechanics, signal acquisition in athletes, animals, among other possibilities). In addition, it is powered by two lithium-ion batteries and autonomy of approximately 3 hours and 18 minutes. Although there were challenges in various stages of the device construction process, for example, in obtaining a high processing capacity and a high data transmission rate, the tests with prototypes show excellent results, consistent with the literature. After the implementation of the hardware, operational tests were performed as well as practical applications the use of a multi-channel electromyographer.
Esse projeto, da área da engenharia biomédica, pertence ao campo promissor de pesquisas em eletromiografia de superfície (EMG-s). Essa tecnologia pode ser usada para o estudo aprofundado de algumas doenças neuromusculares, como por exemplo, polineuropatias, miastenias e miopatias. Utilizando um arranjo de eletrodos multicanal, também podemos obter a decomposição de sinais de EMG-S, estimativa de velocidade de condução das fibras musculares, localização de zonas de inervação (conjunto de pontos motores), entre outras aplicações. Apesar de existirem eletromiógrafos sem fio, não há arranjos de eletrodos sem fio no mercado. Pensando nisso, foi desenvolvido um arranjo linear de dez eletrodos sem fio para eletromiografia de superfície e um conjunto de programas capazes de receber e processar os dados capturados por esse dispositivo. As características alcançadas por esse eletromiógrafo portátil são um baixo custo mesmo quando comparado aos eletromiógrafos de apenas um canal do mercado, 12 bits de resolução, 9216 amostras por segundo (1024 amostras por segundo por canal, com 9 canais e 10 eletrodos utilizando a configuração bipolar), taxa de rejeição de modo comum maior que 50 dB, uma interface que permite interação com computadores via Bluetooth, permitindo pesquisa em diversas áreas (biomecânica, aquisição de sinais em atletas, animais, entre outras possibilidades). Além disso, é alimentado por duas baterias de íon-lítio e possui uma autonomia média de 3 horas e 18 minutos. Apesar de terem surgidos desafios em várias etapas do processo de construção do dispositivo, como por exemplo, a obtenção de uma alta capacidade de processamento e de uma alta taxa de transmissão de dados, os testes com protótipos construídos mostram um resultado excelente e condizente com a literatura. Após a implementação deste hardware, foram realizados testes de funcionamento, assim como aplicações práticas da utilização de um eletromiógrafo de múltiplos canais.
Caldas, Luciano Coutinho. "In-duct beamforming and mode detection using a circular microphone array for the characterisation of broadband aeroengine fan noise." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3142/tde-29082016-142207/.
Повний текст джерелаComo desenvolver de tecnologias para redução de ruído de motores aeronáuticos turbofans, o ruído gerado pelo fan (primeiro estágio do motor) vem se mostrando cada vez mais um grande contribuinte na emissão total de ruído em um avião. Com isso, a necessidade de se estudar mecanismos geradores de ruído nestes motores veio à tona e motivou a construção de uma bancada de experimentos aero-acústicos junto àUniversidade de São Paulo, campus São Carlos, oriundo da parceria entre EMBRAER S.A. e Universidade de São Paulo. A bancada de ensaios compõe um conjunto rotor/estator, sendo que o fan (rotor) é equipado com 16 pás e a estatora 14 pás, conectado a um motor elétrico de 100 hp através de um eixo ao rotor, alcançando 4250 RPM com velocidade de escoamento axial médio de 0,1 Mach. Esta bancada é composta por um longo duto e a seção de ensaio com o fan localiza-se ao centro. Uma antena dispondo de 77 microfones foi especialmente projetada para fazer aquisição do ruído gerado pelo fan. Uma parceria com a NASA-Glenn possibilitou a troca de informações e dados experimentais de sua bancada de experimentos similar (ANCF) ajudando assim a validar os códigos desenvolvidos bem como comparar resultados para ambas as bancadas. Umpequeno roteiro para projeto de antena para análise modal e beamforming em duto é apresentado neste trabalho. Um complexo software foi desenvolvido a fim de processar sistematicamente os dados aquisitados pelos microfones da antena. Três tipos de análise são feitas: Via espectro densidade de potência; Imagem de ruído acústico obtido através da técnica de beamforming, e por último, análise modal. Uma técnica diferente para análise modal baseada em imagens obtidas através de beamforming é proposta neste trabalho. Nada similar foi encontrado nas referências consultadas. Os resultados foram validados com dados de fontes sintéticas produzidas pela bancada ANCF-NASA. Resultados comparativos para ambas as bancadas são exibidas neste trabalho, tais quais: Análise do espectro densidade de potência para diferentes rotações do fan; análise modal nas frequências de passagem das pás (forte ruído tonal gerado pelo fan); imagem acústica do ruído gerado tanto por fontes rotativas quanto para fontes estáticas. Finalmente, os resultados obtidos estão de acordo com o esperado e de antemão observados nas referências consultadas.
Marinho, Marco Antonio Marques. "Array processing techniques for direction of arrival estimation, communications, and localization in vehicular and wireless sensor networks." reponame:Repositório Institucional da UnB, 2018. http://repositorio.unb.br/handle/10482/32685.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).
Técnicas de processamentos de sinais para comunicações sem fio tem sido um tópico de interesse para pesquisas há mais de três décadas. De acordo com o padrão Release 9 desenvolvido pelo consorcio 3rd Generation Partnership Project (3GPP) sistemas utilizando múltiplas antenas foram adotados na quarta geração (4G) dos sistemas de comunicação sem fio, também conhecida em inglês como Long Term Evolution (LTE). Para a quinta geração (5G) dos sistemas de comunicação sem fio centenas de antenas devem ser incorporadas aos equipamentos, na arquitetura conhecida em inglês como massive multi-user Multiple Input Multiple Output (MIMO). A presença de múltiplas antenas provê benefícios como o ganho do arranjo, ganho de diversidade, ganho espacial e redução de interferência. Além disso, arranjos de antenas possibilitam a filtragem espacial e a estimação de parâmetros, ambos podem ser usados para se resolver problemas que antes não eram vistos pelo prisma de processamento de sinais. O objetivo dessa tese é superar a lacuna entre a teoria de processamento de sinais e as aplicações da mesma em problemas reais. Tradicionalmente, técnicas de processamento de sinais assumem a existência de um arranjo de antenas ideal. Portanto, para que tais técnicas sejam exploradas em aplicações reais, um conjunto robusto de métodos para interpolação do arranjo é fundamental. Estes métodos são desenvolvidos nesta tese. Além disso problemas no campo de redes de sensores e redes veiculares são tratados nesta tese utilizando-se uma perspectiva de processamento de sinais. Nessa tesa métodos inovadores de interpolação de arranjos são apresentados e sua performance é testada utilizando-se cenários reais. Conceitos de processamento de sinais são implementados no contexto de redes de sensores. Esses conceitos possibilitam um nível de sincronização suficiente para a aplicação de sistemas de múltiplas antenas distribuídos, o que resulta em uma rede com maior vida útil e melhor performance. Métodos de processamento de sinais em arranjos são propostos para resolver o problema de localização baseada em sinais de rádio em redes veiculares, com aplicações em segurança de estradas e proteção de pedestres. Esta tese foi escrita em língua inglesa, um sumário em língua portuguesa é apresentado ao final da mesma.
Array signal processing in wireless communication has been a topic of interest in research for over three decades. In the fourth generation (4G) of the wireless communication systems, also known as Long Term Evolution (LTE), multi antenna systems have been adopted according to the Release 9 of the 3rd Generation Partnership Project (3GPP). For the fifth generation (5G) of the wireless communication systems, hundreds of antennas should be incorporated to the devices in a massive multi-user Multiple Input Multiple Output (MIMO) architecture. The presence of multiple antennas provides array gain, diversity gain, spatial gain, and interference reduction. Furthermore, arrays enable spatial filtering and parameter estimation, which can be used to help solve problems that could not previously be addressed from a signal processing perspective. The aim of this thesis is to bridge some gaps between signal processing theory and real world applications. Array processing techniques traditionally assume an ideal array. Therefore, in order to exploit such techniques, a robust set of methods for array interpolation are fundamental and are developed in this work. Problems in the field of wireless sensor networks and vehicular networks are also addressed from an array signal processing perspective. In this dissertation, novel methods for array interpolation are presented and their performance in real world scenarios is evaluated. Signal processing concepts are implemented in the context of a wireless sensor network. These concepts provide a level of synchronization sufficient for distributed multi antenna communication to be applied, resulting in improved lifetime and improved overall network behaviour. Array signal processing methods are proposed to solve the problem of radio based localization in vehicular network scenarios with applications in road safety and pedestrian protection.
Trindade, Diego von Brixen Montzel. "Modelagem e simulação de metamaterial para isolamento de campo próximo entre elementos de antenas phased-array." Pontifícia Universidade Católica do Rio Grande do Sul, 2011. http://hdl.handle.net/10923/3221.
Повний текст джерелаPhased-Array antennas are becoming the primary choice for wireless communication solutions. This is due to the fact that controllers already have the computational power required to deal with adaptive algorithms that control the amplitude and phase (through changes in the reactance) of the currents on the array elements in real-time. Along with the increased usage of this technology, the problems related to mutual electromagnetic coupling between elements become evident. On arrays consisted of only one active element and multiple parasite elements (which steer the radiation pattern), as is the case of the ESPAR antenna, it is desirable to have maximum mutual coupling between each parasite element and the active one, however the mutual coupling between parasite elements decreases the overall efficiency of adaptive algorithm being used to optimize the radiating pattern of the array. A solution that has been shown to be effective to minimize the near-field mutual coupling is the use of metamaterials, whose electric and magnetic properties are not found in other natural materials. These metamaterials are capable of attenuating, and even eliminating, the amplitude of electromagnetic waves on specific frequencies. This thesis proposes the use of metamaterials to minimize the near-field mutual coupling between parasite elements of an ESPAR antenna.
Antenas phased-array são cada vez mais utilizadas em soluções de comunicação wireless. Isto se deve ao fato de os processadores já terem um poder computacional suficiente para lidar com algoritmos adaptativos que controlam a amplitude e a fase das correntes nos elementos do array em tempo-real. Junto com o crescente uso desta tecnologia surge o problema do acoplamento eletromagnético entre elementos. No caso de arrays com um elemento irradiante e múltiplos elementos passivos (e. g. Electronically Steerable Passive Array Radiator - ESPAR), o acoplamento entre cada elemento passivo e o elemento ativo é desejável, porém o acoplamento entre elementos passivos representa um esforço a mais que o algoritmo adaptativo deverá fazer para otimizar o diagrama de irradiação. Uma solução que tem se mostrado eficiente para o problema do acoplamento no near-field é o uso de metamateriais, cujas propriedades eletromagnéticas não são encontradas em materiais naturais, e são capazes de atenuar a amplitude de ondas eletromagnéticas em freqüências específicas. Neste contexto, o trabalho em questão propõe o uso de metamaterial para minimizar o acoplamento eletromagnético entre os elementos passivos de uma antena ESPAR.
Cormier, Yannick. "Performance, Manufacturability and Mechanical Properties of Near-Net Shaped Pyramidal Fin Arrays for Compact Heat Exchangers Produced Using Cold Spray as an Additive Manufacturing Technique." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34981.
Повний текст джерелаLorandel, Jordane. "Etude de la consommation énergétique de systèmes de communications numériques sans fil implantés sur cible FPGA." Thesis, Rennes, INSA, 2015. http://www.theses.fr/2015ISAR0036/document.
Повний текст джерелаWireless communication systems are still evolving since the last decades, driven by the growing demand of the electronic market for energy efficient and high performance devices. Thereby, new design constraints have appeared that aim at taking into account power consumption in order to improve battery-life of circuits. Current wireless communication systems commonly dissipate a lot of power. On the other hand, the complexity of such systems keeps on increasing through the generations to always satisfy more users at a high degree of performance. In this highly constrained context, FPGA devices seem to be an attractive technology, able to support complex systems thanks to their important number of resources. According to the FPGA nature, designers need to estimate the power consumption and the performance of their wireless communication systems as soon as possible in the design flow. In this way, they will be able to perform efficient design space exploration and make decisive implementation and optimization choices. Throughout this thesis, a power estimation methodology for hardware-focused FPGA device is described and aims at making design space exploration a lot easier, providing early and fast power and performance estimation at high-level. It also proposes an efficient way to efficiently compare several systems. The methodology is effective through an lP characterisation step and the development of their SystemC models. Then, a high level description of the entire system is realized from the SystemC models that have been previously developed. High-level simulations enable to check the functionality and evaluate the power and performance of the system. One of the contributions consists in monitoring the JP time-activities during the simulation. We show that this has an important impact on both power and performances. The effectiveness of the methodology has been demonstrated throughout several baseband processing chains of the wireless communication domain such as a SISO-OFDM generic chain, LTE transmitters etc. To conclude, the main limitations of the proposed methodology have been investigated and addressed
Vilmann, Peter. "Endoscopic ultrasonography with curved array transducer in diagnosis of cancer in and adjacent to the upper gastrointestinal tract : scanning and guided fine needle aspiration biopsy /." Copenhagen : Munksgaard, 1998. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=007939492&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.
Повний текст джерелаTrindade, Diego Von Brixen Montzel. "Modelagem e simula??o de metamaterial para isolamento de campo pr?ximo entre elementos de antenas phased-array." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2011. http://tede2.pucrs.br/tede2/handle/tede/3033.
Повний текст джерелаAntenas phased-array s?o cada vez mais utilizadas em solu??es de comunica??o wireless. Isto se deve ao fato de os processadores j? terem um poder computacional suficiente para lidar com algoritmos adaptativos que controlam a amplitude e a fase das correntes nos elementos do array em tempo-real. Junto com o crescente uso desta tecnologia surge o problema do acoplamento eletromagn?tico entre elementos. No caso de arrays com um elemento irradiante e m?ltiplos elementos passivos (e.g. Electronically Steerable Passive Array Radiator - ESPAR), o acoplamento entre cada elemento passivo e o elemento ativo ? desej?vel, por?m o acoplamento entre elementos passivos representa um esfor?o a mais que o algoritmo adaptativo dever? fazer para otimizar o diagrama de irradia??o. Uma solu??o que tem se mostrado eficiente para o problema do acoplamento no near-field ? o uso de metamateriais, cujas propriedades eletromagn?ticas n?o s?o encontradas em materiais naturais, e s?o capazes de atenuar a amplitude de ondas eletromagn?ticas em freq??ncias espec?ficas. Neste contexto, o trabalho em quest?o prop?e o uso de metamaterial para minimizar o acoplamento eletromagn?tico entre os elementos passivos de uma antena ESPAR
Jíša, Pavel. "Využití jazyka C při implementaci algoritmů pro FPGA." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219682.
Повний текст джерела大岡, 昌博, Masahiro OHKA, 浩嗣 古賀, Hiroshi KOGA, 徹. 宮岡, Tetsu MIYAOKA, 保永 三矢 та Yasunaga MITSUYA. "高密度ピンアレイ形触覚マウスによる格子状仮想テクスチャ呈示 (第1報,触覚マウスの試作と性能評価実験法の確立)". 日本機械学会, 2005. http://hdl.handle.net/2237/9056.
Повний текст джерелаShirai, Alysson Hikaru. "Estudo e implementação de sistemas de localização em hardware de lógica programável para utilização em rede de sensores sem fio." Universidade Tecnológica Federal do Paraná, 2013. http://repositorio.utfpr.edu.br/jspui/handle/1/511.
Повний текст джерелаRedes de sensores sem fio (RSSF) têm sido tema central de diversos estudos na atualidade. Em certas aplicações, como, por exemplo, as que necessitam saber de onde os dados estão sendo enviados ou em casos em que o próprio nó sensor precisa saber sua posição para executar alguma ação, mecanismos de localização se tornam imprescindíveis. Porém, a execução deste tipo de algoritmo é custosa para os nós sensores. Concomitantemente, o advento das low power FPGAs têm viabilizado a aplicação de dispositivos programáveis em RSSFs e aplicações envolvendo reconfiguração dinâmica de FPGA em nós sensores têm aumentado o uso destes dispositivos nestas redes. Unindo-se estas demandas, o objetivo desta dissertação é estudar e implementar sistemas de localização em hardware de lógica programável, visando atender aplicações voltadas a RSSF. Utilizando-se no nó sensor um bloco de hardware dedicado para realizar os cálculos de posição minimiza a utilização de seu CPU, podendo este hardware, inclusive, ser apenas uma parte de um sistema maior implementado na FPGA. O processo de localização baseia-se na utilização das distâncias entre o nó de posição desconhecida e os nós de referência, determinadas através de medição de RSSI, e o uso de algoritmos específicos que calculam a posição desejada. As principais etapas foram: revisão da literatura, modelagem do comportamento das medições de RSSI, análise do desempenho dos algoritmos e projeto de hardware. Através das simulações realizadas pôde-se desenvolver metodologias e ferramentas para a geração otimizada do hardware de localização. O desenvolvimento deste trabalho possibilitou analisar a aplicabilidade do ponto flutuante e ponto fixo, definir a arquitetura adequada para o hardware e o dimensionamento adequado da quantidade de bits necessária nas implementações.
Wireless sensor networks (WSN) have been the central theme of many researches in actuality. In certain applications, like, for example, the ones that need to know from where the data is being sent or in cases which the sensor node need to know its own position to perform some action, location mechanism is indispensable. However, the execution of these algorithms is costly for the sensor nodes. Concomitantly, the advent of low power FPGAs made feasible the application of programmable devices in WSNs and applications involving dynamic reconfiguration of FPGA in sensor nodes increased the use of these devices in WSNs. Joining these demands, the goal of this master thesis is to study and implement locating systems in programmable logic hardware, aiming at meeting applications in WSN. Employing a dedicated hardware block in sensor node to compute the position minimizes its CPU usage, and this hardware can even be just a part of a larger system implemented in FPGA. The localization process is based on the use of distances, measured between the sensor node with unknown position and the reference nodes, determined from RSSI measurements, and the use of specific algorithms that calculate the desired position. The main steps were: review of the literature, modeling the behavior of the RSSI measurements, performance analysis of the algorithms and hardware design. Through the performed simulations it was possible to develop methodologies and tools to generate optimized locating hardware. The development of this work allowed to evaluate the feasibility of the floating point and fixed point, to set the appropriate architecture for the hardware and to find the proper dimension of the number of bits required in the implementations.
Vandelle, Erika. "Exploration de solutions antennaires et de formation passive de faisceaux pour la récupération et le transfert d’énergie sans fil." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT060.
Повний текст джерелаWireless energy harvesting (WEH) of ambient or intentional electromagnetic power sources of frequency ranging from 100 MHz to 10 GHz, has appeared as a promising solution to develop self-powered electronics in the past decades. However, the low power densities available, usually lower than 1 uW.cm-2, result in a limited RF-to-DC conversion efficiency and sensitivity of the energy harvesting system (rectenna) and the ambient signal diversities (unknown and time-varying direction of arrival, polarization) prohibit the use of directive antennas.In this thesis, the power combination techniques of Radio Frequency (RF) or Direct Current (DC) power in multi-antenna WEH systems, together with original structures, are investigated to address those challenges. Besides, a new Figure-of-Merit (harvesting capability) for rectennas operating in ambient scenarios is derived with probabilistic terms representing the frequency, polarization and spatial diversities of ambient signals.The first part of this thesis focuses on the design of efficient antenna and rectenna elements. Eco-responsible and low-cost prototypes are proposed by using a paper substrate along with an original strategy for the reduction of the losses.In the second part of this work, the rectification efficiency of a WEH system is enhanced through the combination of the RF power prior to the rectification process, without reduction of the spatial coverage. For this, a 3D multidirectional structure of scanning antenna arrays using passive beam-forming networks is designed to obtain a multidirectional high gain aggregate pattern. This radar-inspired solution involving Butler matrices results in a highly efficient RF-to-DC power conversion along with an optimal angular coverage, which leads to a harvesting capability higher than the state-of-the-art.The last part of this work addresses the limited sensitivity of the RF combination technique compared to that obtained with the series DC combination technique thanks to a reconfigurable system. To this end, modular rectenna unit cells are designed to form a scalable and adaptative interferometric beam-forming network, which offers the possibility to achieve a highly efficient and sensitive WEH system. This solution is suitable for low-power energy harvesting, autonomous passive tracking or RFID applications
Hussein, Ali Abdulsattar. "Photonic Integrated Circuits Utilizing Nano-Electromechanical Systems on Silicon-on-Insulator Platform for Software Defined Networking in Elastic Optical Networks: New Insights Into Phased Array Systems, Tunable WDM, and Cascaded FIR and IIR Architectures." Thesis, Université d'Ottawa / University of Ottawa, 2019. http://hdl.handle.net/10393/39592.
Повний текст джерелаVykydal, Martin. "Zpracování signálu z digitálního mikrofonu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-218904.
Повний текст джерела大岡, 昌博, Masahiro OHKA, 浩嗣 古賀, Hiroshi KOGA, 徹. 宮岡, Tetsu MIYAOKA, 保永 三矢 та Yasunaga MITSUYA. "高密度ピンアレイ形触覚マウスによる格子状仮想テクスチャ呈示 (第2報,触知ピン間隔,テクスチャ密度および畝高さの検討)". 日本機械学会, 2006. http://hdl.handle.net/2237/9055.
Повний текст джерелаVillafañe, Roca Laura. "Experimental Aerothermal Performance of Turbofan Bypass Flow Heat Exchangers." Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/34774.
Повний текст джерелаVillafañe Roca, L. (2013). Experimental Aerothermal Performance of Turbofan Bypass Flow Heat Exchangers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34774
TESIS
Bazzi, Ahmad. "Techniques d'estimation de paramètres pour la localisation à l'intérieur via WiFi." Thesis, Paris, ENST, 2017. http://www.theses.fr/2017ENST0051/document.
Повний текст джерелаIn an indoor environment, the problem of extracting the Angle-of-Arrival of the Line-of-Sight component between a transmitter and Wi-Fi receiver using a SIMO link is the main concern of this thesis. One main challenge in doing so is due to the rich multipath channel that indoor environments enjoy. This is so because multipath results from the fact that the propagation channel consists of several obstacles and reflectors. Thus, the received signal arrives as an unpredictable set of reflections and/or direct waves each with its own degree of attenuation and delay. Other challenges are limitation of resources, such as number of antennas, available bandwidth, and Signal-to-Noise-Ratio; not to mention the Wi-Fi ”imperfections”, such as gain/phase mismatches between antennas and synchronisation issues between transmitter and receiver. In this thesis, our main focus is implementing a real-time system that could measure the angle between a transmitter and receiver in the presence of all challenges. In particular, we have taken into account all factors that perturb the Joint Angle and Delay estimation problem and formulated a system model accordingly. These factors are: Sampling Frequency offset (SFO), Carrier Frequency Offset (CFO), Phase and Delay offsets at each antenna. To compensate for the effect of these critical factors, we propose an offline calibration method to compensate for all their effects. This thesis will also include other theoretical methods that have to deal with Angle-of-Arrival Estimation problem from compressed sensing and signal processing point of views
Rozé, Antoine. "Massive MIMO, une approche angulaire pour les futurs systèmes multi-utilisateurs aux longueurs d’onde millimétriques." Thesis, Rennes, INSA, 2016. http://www.theses.fr/2016ISAR0014/document.
Повний текст джерелаAs wireless communication networks are driven toward densification with small cell deployments, massive MIMO technology shows great promises to boost capacity through beamforming techniques. It is also well known that millimeter-Wave systems are going to be an important part of future dense network solutions because, not only do they offer high bandwidth, but channel is mostly Line-of-Sight (LOS). The attractiveness of using a multi-user Massive MIMO system at these frequencies comes partly from the reduced size of a many antenna base station, but also from the high beamforming gains they provide, which is highly suited to combat the high path losses experienced at such small wavelengths. First we show how raising the carrier frequency impacts the performance of some linear precoders widely used in Massive MIMO systems. By means of a geometrical deterministic channel model, we simulate a dense outdoor scenario and highlight the influence of the direct and multi-paths components. More importantly we prove that, in a Line-of-Sight (LOS) configuration, the discriminating skill of the well-known Zero Forcing precoder is much more sensitive to the antenna array structure and the user location than the Conjugate Beamforming precoder, also known as Time-Reversal. A precoder based on the knowledge of the angular position of all users is then introduced and compared to the other precoders based on channel response knowledge. Its robustness against angle estimation error is illustrated for a specific scenario and serves to back up the importance such a solution represents for future dense 5G networks, angular information being easier to estimate, and more so to keep track of.After that, we show how the knowledge of Directions of Arrival can be used to increase the sum capacity of a multi-user transmission through leakage based power allocation. This allocation uses an estimation of inter-user interference, referred to as Leakage, and we show through simulations how this factor, even under its most simplified form, improves realistic transmissions. Moreover this solution is not iterative and is extremely easy to implement which makes it particularly well suited for high deployment scenarios.Finally we introduce the Hybrid Analog and Digital Beamforming systems that have recently emerged to retain a high number of antennas without as many Radio Frequency (RF) chains, in order to keep high beamforming gains while lowering the complexity of conceiving many antenna base stations. We first describe a user equipment solution allowing the system to form a beam that adapts to its own movement so that it always focuses its energy toward the base station, using an on-board analog array and an Inertial Measurement Unit. Then we compare the performance of a known Hybrid solution with a fully digital Massive MIMO system, having as many RF chains as the Hybrid system, but serving user equipments with beamforming abilities. Mostly we emphasize how such a system allows for great flexibility and evolution, both traits being invaluable features in many future networks
Chiniard, Renaud. "Contribution à la modélisation de la surface équivalente radar des grandes antennes réseaux par une approche multi domaine/Floquet." Toulouse 3, 2007. http://www.theses.fr/2007TOU30295.
Повний текст джерелаThis study proposes to treat large array antennas with an original approach. It makes it possible to reach problems whose great dimensions lead traditional and rigorous methods to be unsuccessful. The first part is devoted to the description of the employed methods. The first one is the multi domain method which makes it possible to split in sub domains the initial problem. Each domain is then calculated using the numerical method (integral equations, finite elements,…) adapted. It allows to obtain a condensed operator (S matrix) for each sub domain in an uncoupled way. Once they have been put together with the feeding, the problem can be solved. The main advantage lies in the modular approach which makes it very efficient in parametric studies by re-use of the matrices S of unchanged volumes. We further present the development in Floquet modes, assuming the planar, infinite and periodic hypothesis. It thus makes it possible to reduce the problem to the size of the elementary cell. In the second part, the hybridization of the two methods previously introduced is shown. It is discussed on a rectangular guide array case which, in addition to validating our approach, allows the installation of physical indicators. To enhance our tool, in the next chapter we couple the array to its mechanical support and propose an efficient modelling of this global realistic antenna. The final chapter makes it possible to confront our code with the measurements of one real array antenna. It allows to estimate all the capabilities of the method developed during this study. At the end of this study, a software tool has been developed and it makes it possible to calculate Radar Cross Section of the large antenna arrays inserted in their supports and for various conditions of feeding impedances
Torres, Villa Robinsón Alberto. "Instrumental techniques for improving the measurements based on Quartz Crystal Microbalances (Técnicas instrumentales para mejorar las mediciones con microbalanzas de cuarzo)." Doctoral thesis, Universitat Politècnica de València, 2012. http://hdl.handle.net/10251/17323.
Повний текст джерелаTorres Villa, RA. (2007). Instrumental techniques for improving the measurements based on Quartz Crystal Microbalances (Técnicas instrumentales para mejorar las mediciones con microbalanzas de cuarzo) [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/17323
Palancia
Le, Pelleter Tugdual. "Méthode de discrétisation adaptée à une logique événementielle pour l'utra-faible consommation : application à la reconnaissance de signaux physiologiques." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT043/document.
Повний текст джерелаOur everyday life is highly dependent on mobile embedded systems. In order to make them suitable to differentapplications, they have underwent size reduction and lifetime extension. However, these improvementsare currently limited by the possibilities of the integrated circuits technologies. In order to push back theboundaries, it is necessary to reconsider the whole digital signal processing chain from scratch to sustain thepower consumption reduction in this kind of system. This work develops on the first hand a strategy thatsmartly uses the level-crossing sampling scheme and on the other combines this sampling method with eventlogicto highly reduce the power consumption in mobile embedded systems. A discretisation method adaptedto the recognition of physiological patterns application is described. A first event-logic (asynchronous) prototypeimplemented on FPGA proved the potential benefits that an adapted sampling scheme could offersto reduce activity compared to a uniform sampling scheme. Electrical simulations performed on a secondprototype, also designed in asynchronous logic, with CMOS AMS 0.35 μm technology, validated a high gainin power consumption
Masucci, Antonia Maria. "Moments method for random matrices with applications to wireless communication." Thesis, Supélec, 2011. http://www.theses.fr/2011SUPL0011/document.
Повний текст джерелаIn this thesis, we focus on the analysis of the moments method, showing its importance in the application of random matrices to wireless communication. This study is conducted in the free probability framework. The concept of free convolution/deconvolution can be used to predict the spectrum of sums or products of random matrices which are asymptotically free. In this framework, we show that the moments method is very appealing and powerful in order to derive the moments/asymptotic moments for cases when the property of asymptotic freeness does not hold. In particular, we focus on Gaussian random matrices with finite dimensions and structured matrices as Vandermonde matrices. We derive the explicit series expansion of the eigenvalue distribution of various models, as noncentral Wishart distributions, as well as correlated zero mean Wishart distributions. We describe an inference framework so flexible that it is possible to apply it for repeated combinations of random ma- trices. The results that we present are implemented generating subsets, permutations, and equivalence relations. We developped a Matlab routine code in order to perform convolution or deconvolution numerically in terms of a set of input moments. We apply this inference framework to the study of cognitive networks, as well as to the study of wireless networks with high mobility. We analyze the asymptotic moments of random Vandermonde matrices with entries on the unit circle. We use them and polynomial expansion detectors in order to design a low complexity linear MMSE decoder to recover the signal transmitted by mobile users to a base station or two base stations, represented by uniform linear arrays
Šimeček, Ondřej. "Problematika šablonového tisku pájecí pasty pro součástky s malou roztečí vývodů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-218992.
Повний текст джерелаChang, Jim M., and 張明. "Analysis of thermally optimized fin array." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/24039929804845685842.
Повний текст джерела國立海洋大學
航海技術學系
83
This study presents the relationship between fin geometry and heat transfer rate in the optimum design of longitudinal fin arrays in forced convection. Four kinds of fin shapes: the rectangular, convex-parabolic, triangular, and concave- parabolic cross section are analyzed. The aspect ratio, interfin spacing, and heat transfer characteristics of the optimal array are determined chiefly by the basis of the fixed size of the total root area and the volume of all fins, and the assumptions of constant thermal properties. Through the modeling of derivative interfin spacing, it has determined the optimum aspect ratio as well as the spacing decreases while the total heat transfer rate increases at high Biot number. In the chosen four profile, the heat transfer rate gained the most in the arrays with concave- parabolic profile, whereas the rectangular design gained the least. The optimum aspect ratio and interfin spacing are inversely proportional to the profile index. From the modeling of derivative fin base thickness, it is concluded that the aspect ratio of optimal fin arrays has very little to do with the Biot numbers. Both the dimensionless heat transfer rate and fin spacing increase with fin parameter and Biot number. The heat duties of optimum arrays are ranked in the following order: 1. rectangular-fin, 2. convex-parabolic- fin, 3. triangular-fin, 4.concave-parabolic-fin arrays. However, the differences in heat duty are not significicant for the above-mentioned four arrays. The influence of humidity of ambient air is also important. It shows that a significant reduction in optimum aspect ratio and interfin spacing when relative humidity is increased. The added moisture has enhances the heat transfer rate in all cases. The results of this work are presented in dimensionless form for the convenience of parametric study and easy reference in the design analysis for others.
Jia-ChenGuo and 郭嘉振. "Investigation of Fin-Nano-Array AlGaN/GaN MOS-HEMTs." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/s8acx8.
Повний текст джерелаHuang, Ren-Chan, and 黃任禪. "Numerical Analysis of the Thermal Modules of Fin Array in Different Configurations." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/69874438907200006924.
Повний текст джерела國立臺灣海洋大學
機械與機電工程學系
98
The objective of this thesis is to investigate the effectiveness of the fin array applied in computers or other electronic equipments by both analytical and numerical analysis in an effort to improve its cooling and avoid overheating. As modern computer technology advances, The power consumption of its processors also increases and combines with a substantial increase in the chip temperature. The processors should be maintained at a certain temperature for proper operation and long service life. So, it is a major thermal design challenge to transfer waste heat from the chips effectively and avoid heat concentration inside the chips board. A combination of fin array and fan set up is one of the main thermal technologies in the cooling of micro processors. Several different configurations of fin array, fin geometry, and shapes are investigated so that some guidelines could be achieved in the design and application of fin array. ANSYS software package and other analytical means are used for the numerical simulation in the thesis. The effects fin array in a different geometry, shape, and size are discussed, which are divided into following: 1. Fin thickness, height, spacing, number of fins, fin material. 2. Different shapes of fin. 3. Optimization in the fin array design. Another major challenge in the design of fin array is the estimate of convective heat transfer coefficient. Several empirical correlations are used and CFD Fluent software is applied to validate the use of empirical formula. More accurate convective heat transfer coefficient could be obtained through higher computing speed and better experimental data in the future, which will help in the design analysis of fin array.
Lin, Zhi-You, and 林芝佑. "Influence of Air Flow Arrangement on the Performance of Heat Sink with Rectangular Plate Fin and Square Pin Fin Array." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/91859028465333239591.
Повний текст джерела國立雲林科技大學
機械工程系碩士班
93
An experimental study is conducted on forced convection heat transfer from heat sinks. A total of twelve heat sinks with six plate fin and six pin fin configurations are tested subjecting to confined cross flow, partially-confined cross flow and impingement flow conditions. The purpose of the present study can be divided into three parts: observation of the effect of the frontal velocity on the thermal resistance, investigation of the differences between confined cross flow and partially-confined cross flow, and examination of the performances under confined cross flow and impingement flow. Generally, the thermal resistance of the heat sinks decreases with increasing the frontal velocity and the total convective area. For a frontal velocity (Vfr) of 5m/s, the heat transfer coefficients of the staggered pin fins are 33% higher than those of the in-line pin fins and 50% higher than those of the plate pins, accompanying an increase of the pressure drops by 45% and by 50%, respectively. In addition, both the heat transfer coefficients and the pressure drops under confined cross flow are larger than those under partially-confined cross flow. For a frontal velocity of 5m/s, an enhancement of 15% for the heat transfer coefficients and 35% for the pressure drops are observed. For the comparison between the confined cross flow and the impingement flow, the heat transfer coefficients under impingement flow outperform those under confined cross flow by about 45% at the expense of tremendous pressure drops by 7 ~ 10 times.