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Dissertations / Theses on the topic 'Directivity'

Author: Grafiati

Published: 4 June 2021

Last updated: 25 July 2025

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1

Basta, Nina Popovic. "Multilayer scalable coupler with high directivity." Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/53955.

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This thesis addresses the design, analysis, and experimental validation of a high-directivity and high coupling microwave directional coupler. The motivating application is in broadband signal routing between cores of multi-core processors, where the delay of simple wire interconnects introduces unacceptable latency. The performance goals include scalability with frequency, a coupling coefficient of 3 dB, directivity larger than 40 dB, high return loss, low insertion loss below 3 dB at the center frequency, and small footprint. The approach to this problem taken in the thesis is a combination

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2

Loveridge, M. M. "Marine seismic source signatures : directivity and the ghost." Thesis, University of Oxford, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.355760.

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3

Ivars, Morón Diego. "Optimizing the directivity index of a two-way loudspeaker." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-11108.

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Performance of the loudspeaker in a common living room is analyzed in this project. Moreover, directivity parameters like Directivity Index and polar Directivity Diagram are studied taking as example one specific tweeter construction. Some writers suggest that largely frequency-independent Directivity Index is preferable for loudspeakers in an ordinary indoor stereo setup. To achieve this goal, variation of the original radiation diagram of the studied tweeter is performed including reflectors in the system. A measurement protocol is designed and used. Obtained data is processed by developed s

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4

Foltz, Eleanor R. (Eleanor Ruth). "Two dimensional control of metamaterial parameters for radiation directivity." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37199.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.<br>Includes bibliographical references (leaves 77-80).<br>This work examines the feasibility of using metamaterials to direct radiation. The limits of required index of refraction and the required material depth are explored using MATLAB simulations. A wedge of connected S-shape metamaterial is chosen and simulated in CST Microwave Studio. The incident radiation is Transverse Magnetic (TM) and negative deflection is achieved. The S-shape wedge is adjusted in small ways, and a sp

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5

Sviridova, T. V. "The development to ecological directivity of the operation enterprise." Thesis, Вид-во СумДУ, 2010. http://essuir.sumdu.edu.ua/handle/123456789/13191.

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6

Wang, Zhiwei, and Shen Zhang. "Design of 5G antenna arrays based on Multi-directivity." Thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-95135.

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As communication technology evolves, the focus shifts to 5G. The discussion of 5G cannot be separated from a discussion of related antenna systems. Chapter 1 is a brief introduction to our work, which is an antenna array for a 5G communication system operating in the band 3.4 to 3.8 GHz. This is a common band for 5G in Europe. Background and theory are presented in Chapters 2 and 3. In Chapter 4, the design has been simulated with the software CST Studio Suite. We study an antenna group that consists of four linear arrays that together cover all directions. The gain eventually reaches 12dB in

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7

Juyal, Prateek. "Directive microstrip disc radiators based on TM1m modes." IEEE TAP, 2016. http://hdl.handle.net/1993/32074.

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Fundamental TM11 mode of circular microstrip antennas has a limitation of low broadside gain. This thesis explores and investigates the possibility of designing high gain circular microstrip antennas by using higher zeros of the first order mode, or the TM1m modes. Deficiencies in the existing methods of gain enhancement, motivates the need to look for new methods. This is done by first investigating the radiation characteristics of TM1m modes, and then providing techniques for sidelobe suppression in their radiation patterns. Several approaches are proposed and corresponding to each developed

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8

Larsson, Kristina. "Assessment of directivity of real noise sources- Application to vehicles." Thesis, KTH, Farkost och flyg, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-151025.

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The aim of this project is to evaluate a new method for noise directivity measurements; whether a room correction factor can be used to compensate for the effect of a light reverberation field. Another aim is to find if there is any suitable standard to use. No standard to use fully was found, but SS-EN ISO 3744:2010 has a method to compensate for reverberation upon which the present method is based. Measurements were performed for three objects in a semi anechoic room and two ordinary rooms. Sound pressure was measured for all multiples of 30° in the horizontal plane where the acoustic centre

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Friman, Manne. "Directivity of sound from wind turbines : A study on the horizontal sound radiation pattern from a wind turbine." Thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-48926.

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In the present paper, a study on the directivity of sound from a wind turbine has been conducted. The aim of the study is to investigate the horizontal sound radiation pattern through a field study compared to a noise prediction. The benefit of the results may be used to optimize the output effect from the wind turbine while the guidelines for noise levels at nearby residential areas still are met. The complete directivity pattern around the wind turbine was investigated by performing emission measurements around the wind turbine from a method described in IEC 61400-11 Wind turbine generator s

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10

Bonvalot, Eliot. "Dynamic response of bridges to near-fault, forward directivity ground motions." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Summer2006/e%5Fbonvalot%5F072606.pdf.

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11

Ziolkowski, Richard W. "The directivity of a compact antenna: an unforgettable figure of merit." EDP SCIENCES S A, 2017. http://hdl.handle.net/10150/626104.

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When an electrically small antenna is conceived, designed, simulated, and tested, the main emphasis is usually placed immediately on its impedance bandwidth and radiation efficiency. All too often it is assumed that its directivity will only be that of a Hertzian dipole and, hence, its directivity becomes a minor consideration. This is particularly true if such a compact antenna radiates in the presence of a large ground plane. Attention is typically focused on the radiator and its size, while the ground plane is forgotten. This has become a too frequent occurrence when antennas, such as patch

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12

Sterba, Ron. "Distortion directivity and circuit modeling of a needle array plasma loudspeaker." Ohio : Ohio University, 1991. http://www.ohiolink.edu/etd/view.cgi?ohiou1183749470.

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13

Bodon, K. Joshua. "Development, Evaluation, and Validation of a High-Resolution Directivity Measurement System for Played Musical Instruments." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5653.

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A high-resolution directivity measurement system at Brigham Young University has been renovated and upgraded. Acoustical treatments have been installed on the microphone array, professional-grade audio hardware and cabling have been utilized, and user-friendly MATLAB processing and plotting codes have been developed. The directivities of 16 played musical instruments and several loudspeakers have been measured by the system, processed, and plotted. Using loudspeakers as simulated musicians, a comprehensive analysis was completed to validate the system and understand its error bounds. A compari

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14

Mobley, Frank Spencer. "Further development of 3-D rotary-wing acoustic directivity using a spherical harmonic representation." University of Dayton / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1335543552.

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15

Eyring, Nicholas J. "Development and Validation of an Automated Directivity Acquisition System Used in the Acquisition, Processing, and Presentation of the Acoustic Far-Field Directivity of Musical Instruments in an Anechoic Space." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/4004.

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A high spatial resolution acoustic directivity acquisition system (ADAS) has been developed to acquire anechoic measurements of the far field radiation of musical instruments that are either remote controlled or played by musicians. Building upon work performed by the BYU Acoustic Research Group in the characterization of loudspeaker directivity, one can rotate a musical instrument with sequential azimuthal angle increments under a fixed semicircular array of microphones while recording repeated notes or sequences of notes. This results in highly detailed and instructive directivity data prese

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Anagnostopoulos, Eleftherios. "Modélisation de la génération d'ultrasons par laser : application à l'inspection de composants aéronautiques métalliques et composites." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0043/document.

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Le Contrôle Non Destructif par ultrasons-laser est une technique attractive pour l'industrie aéronautique de par son caractère entièrement sans contact et permet l'inspection rapide etefficace de composants mécaniques complexes. L'objectif de ces travaux de thèse concerne lamodélisation de la génération d'ultrasons par laser dans les composants aéronautiques, métalliques etcomposites, de géométrie bicouche. Nous cherchons en effet à étudier l’influence sur le mécanisme degénération ultrasonore d’un revêtement tel qu’une couche superficielle de peinture ou de résine. Dansun premier chapitre, no

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Pollow, Martin Verfasser], Michael [Akademischer Betreuer] [Vorländer, and Peter [Akademischer Betreuer] Vary. "Directivity patterns for room acoustical measurements and simulations / Martin Pollow ; Michael Vorländer, Peter Vary." Aachen : Universitätsbibliothek der RWTH Aachen, 2015. http://d-nb.info/1127337165/34.

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Pollow, Martin [Verfasser], Michael [Akademischer Betreuer] Vorländer, and Peter [Akademischer Betreuer] Vary. "Directivity patterns for room acoustical measurements and simulations / Martin Pollow ; Michael Vorländer, Peter Vary." Aachen : Universitätsbibliothek der RWTH Aachen, 2015. http://nbn-resolving.de/urn:nbn:de:hbz:82-rwth-2015-047810.

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19

Varada, Vijay K. "Acoustic Localization Employing Polar Directivity Patterns of Bidirectional Microphones Enabling Minimum Aperture Microphone Arrays." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1290118825.

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20

Miranda, Jofre Luis Alejandro. "The acoustics of concentric sources and receivers – human voice and hearing applications." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15506.

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One of the most common ways in which we experience environments acoustically is by listening to the reflections of our own voice in a space. By listening to our own voice we adjust its characteristics to suit the task and audience. This is of particular importance in critical voice tasks such as actors or singers on a stage with no additional electroacoustic or other amplification (e.g. in ear monitors, loudspeakers, etc.). Despite the usualness of this situation, there are very few acoustic measurements aimed to quantify it and even fewer that address the problem of having a source and receiv

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Hildebrandt, Andre [Verfasser]. "Design and fundamentals of optical nanoantennas for high intensity enhancement or high directivity / Andre Hildebrandt." Paderborn : Universitätsbibliothek, 2017. http://d-nb.info/1129252361/34.

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Joshi, Varun Anil. "Near-Fault Forward-Directivity Aspects of Strong Ground Motions in the 2010-11 Canterbury Earthquakes." Thesis, University of Canterbury. Department of Civil and Natural Resources Engineering, 2013. http://hdl.handle.net/10092/8987.

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The purpose of this thesis is to conduct a detailed examination of the forward-directivity characteristics of near-fault ground motions produced in the 2010-11 Canterbury earthquakes, including evaluating the efficacy of several existing empirical models which form the basis of frameworks for considering directivity in seismic hazard assessment. A wavelet-based pulse classification algorithm developed by Baker (2007) is firstly used to identify and characterise ground motions which demonstrate evidence of forward-directivity effects from significant events in the Canterbury earthquake sequenc

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23

Woolston, Scott R. "Development of methods to propagate energy density and predict farfield directivity using nearfield acoustic holography /." Diss., CLICK HERE for online access, 2009. http://contentdm.lib.byu.edu/ETD/image/etd3016.pdf.

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24

Warren, Linda M. "Analysis of global compressional-wave spectra to determine anelastic earth structure and earthquake rupture directivity /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3100367.

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Woolston, Scott Richard. "Development of Methods to Propagate Energy Density and Predict Farfield Directivity Using Nearfield Acoustic Holography." BYU ScholarsArchive, 2009. https://scholarsarchive.byu.edu/etd/1726.

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Acoustical-based imaging systems have found merit in determining the behavior of vibrating structures. This thesis focuses on the continued development of the nearfield acoustic holography (NAH) approach. Conventional NAH consists of first measuring the pressure field on a two-dimensional conformal surface and then propagating this data back to the vibrating structure to obtain information about the source, such as the normal velocity distribution. Recent work has been done which incorporates particle velocity information into the traditional NAH measurements to reduce the number of measuremen

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Ramanandraibe, Marosoa Esthelladi. "Miniaturisation des antennes de station de base RFID dans la bande UHF et leur fonctionnement en multibande, par l'utilisation de métamatériaux." Thesis, Rennes 1, 2016. http://www.theses.fr/2016REN1S125.

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Les dimensions d’une antenne sont inversement proportionnelles à leurs fréquences de fonctionnement. De plus, la miniaturisation d’une antenne entraîne la dégradation de ses performances électriques et de rayonnement. Par conséquent, il est important pour le concepteur de trouver un bon compromis entre le taux de miniaturisation et les performances souhaitées. L’objet de cette thèse est de proposer une antenne miniature possédant les meilleures caractéristiques possibles dans la bande UHF de la RFID (860MHz – 960MHz), facile à réaliser et à moindre coût d’industrialisation. Les travaux de cett

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27

Sharma, R. "Simulation studies on effects of dual polarisation and directivity of antennas on the performance of MANETs." Thesis, Coventry University, 2014. http://curve.coventry.ac.uk/open/items/4cc65581-8030-45bc-8136-82fdf902052e/1.

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In the purview of efficient communication in MANETs for enhanced data rates and reliable routing of information, this thesis deals with dual polarised directional antenna based communication. This thesis proposes a dual polarised directional communication based cross-layer solution to mitigate the problems of interference, exposed nodes, directional exposed nodes, and deafness, and to achieve efficient routing of information. At the physical layer of network protocol stack, this thesis proposes the use of dual polarised directional antenna for the mitigation of interference. Use of dual polari

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28

Ouarradi, Noureddine. "Etude théorique et expérimentale du champ ultrasonore transitoire généré par un transducteur plan dans un milieu solide homogène et isotrope : Approche de la réponse impulsionnelle de diffraction." Valenciennes, 1999. https://ged.uphf.fr/nuxeo/site/esupversions/00c238b0-7907-4a5d-a70f-ddf9c707e8e9.

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L’objet de cette thèse est le développement d'un code de calcul, basé sur une formulation mathématique explicite, permettant de calculer le champ de déplacement transitoire généré par un transducteur ultrasonore plan, en contact direct avec un milieu solide, homogène et isotrope. La formulation adoptée introduit la fonction de green élastodynamique temporelle. La réponse impulsionnelle de déplacement est donnée sous forme d'une somme de trois intégrales de surface, qui représentent respectivement les contributions des ondes de compression, de cisaillement et de la combinaison de ces deux ondes

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29

Habert, Benjamin. "Contrôle de la fluorescence par des nanoantennes plasmoniques." Phd thesis, Palaiseau, Institut d'optique théorique et appliquée, 2014. http://pastel.archives-ouvertes.fr/pastel-01023199.

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Dans ce travail de these, nous étudions comment des nano-structures métalliques modifient le processus d'émission spontannée d'objets fluorescents et jouent ainsi un rôle d'antenne. Ces structures supportent des modes optiques confinés aux interfaces metal-diélectrique: ce sont des modes plasmoniques.De par leur fort confinement, ces modes modifient la densité locale d'états optiques et permettent notamment d'accélérer le processus d'émission spontannée (facteur de Purcell). Nous étudions le cas d'une structure planaire metal-isolant-métal de type patch couplée à un ensemble de nanocristaux co

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Souai, Sana. "Réseaux d’antennes miniatures super-directifs reconfigurables basses fréquences pour l’IoT." Thesis, Université Côte d'Azur, 2021. http://www.theses.fr/2021COAZ4020.

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L'Internet des objets (IoT) fait référence à tout système où les objets sont connectés à Internet, il intègre une architecture de connectivité réseau, des capteurs et des appareils intelligents. Selon des recherches récentes, environ 30 milliards d'objets collectent désormais des données et effectuent toutes sortes de tâches. Déployées dans des environnements intelligents, tels que les maisons intelligentes, les villes intelligentes et les transports intelligents.Le but de cette thèse est le développement dans un espace réduit, réseau d'antennes miniatures basse fréquence, en vue d’atteindre u

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Weiler, Bradley. "Finite Element Method Based Analysis and Modeling in Rotordynamics." University of Cincinnati / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1510917784717535.

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PETRIS, GIOVANNI. "Physics and modelling of generation and propagation of noise by complex sources in realistic basins." Doctoral thesis, Università degli Studi di Trieste, 2023. https://hdl.handle.net/11368/3042165.

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The need to develop more accurate numerical tools for the propagation of noise in underwater environments is driven by the continuous increase of human activity in the sea and coastal areas. Noise has been shown to be dangerous to marine wildlife, and steps should be taken soon to mitigate it. Knowing that the primary sources of noise pollution at sea are marine propellers, one of the problems is assessing how the noise generated interacts with the environment, since up to now, the main focus was the characterization of the acoustic signature in the near field or, alternatively, the propagatio

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Mieskoski, Randy. "Capturing and Modeling a Three-Dimensional Stationary Noise Source Directivity Pattern with a Dynamic Array in the Near Field." Wright State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=wright1387979181.

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Cambridge, Jason Esan. "The Sound Insulation of Cavity Walls." Thesis, University of Canterbury. Mechanical Engineering, 2012. http://hdl.handle.net/10092/7332.

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Lightweight building materials are now commonly employed in many countries in preference to heavyweight materials. This has lead to extensive research into the sound transmission loss of double leaf wall systems. These studies have shown that the wall cavity and sound absorption material placed within the cavity play a crucial role in the sound transmission through these systems. However, the influence of the wall cavity on the sound transmission loss is not fully understood. The purpose of this research is to obtain a comprehensive understanding of the role played by the wall cavity and any

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Oliveira, Alexandre Maniçoba de. "Desenvolvimento e otimização de antenas Vivaldi antipodais para aplicações a altas frequências." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/3/3140/tde-21062016-145910/.

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Esta tese propõe a síntese e o estudo de uma nova técnica de cavidades de borda aplicada a antenas Vivaldi, com o intuito de melhorar suas características de diretividade. Embora as antenas do tipo Vivaldi possuam características diretivas, elas produzem radiações laterais indesejáveis, o que se reflete nos elevados índices de lóbulos laterais devido a correntes superficiais que fluem ao longo das bordas metalizadas nas laterais da antena. Estas correntes são a origem das radiações laterais que vêm sendo mitigadas pela aplicação de cavidades ressonantes, triangulares ou retangulares, que apris

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Oliveira, Lucas Rangel de. "Concepção de um índice para localização de trincas em eixos rotativos através da análise do SDI (Shape and Directivity Index) /." Ilha Solteira, 2019. http://hdl.handle.net/11449/180841.

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Orientador: Gilberto Pechoto de Melo<br>Resumo: A identificação de trincas ainda é um desafio na área de monitoramento da integridade estrutural em eixos rotativos. Embora muitas técnicas e modelos tenham sido desenvolvidos, encontrar uma técnica eficiente que possa localizar uma única ou múltiplas trincas ao longo do eixo, ainda é um grande desafio. Nesse trabalho, um novo índice para localização de trincas em eixos rotativos é apresentado. A equação do movimento do rotor com trinca utiliza a notação em coordenadas complexas a fim de separar as contribuições dos modos de precessão direta e re

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Bonfanti, Thierry. "Phénoménologie de la situation médiative." Thesis, Brest, 2012. http://www.theses.fr/2012BRES0007/document.

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M’interrogeant sur l’inflation du mot « médiation », j’ai passé en revue quelques unes des pratiques les plus courantes invoquant un terme dont j’ai pu en constater, dans certains cas, l’usage abusif. À partir de là, j’ai tenté de tracer les contours d’un concept en mal de définition. J’ai ainsi dégagé deux caractéristiques intrinsèques de la médiation, à savoir la triangularité et la non-directivité ainsi que ses deux prérequis que sont le libre consentement des participants et la légitimation du médiateur. Par ailleurs, j’ai constaté que la médiation ne s’appliquait pas qu’aux situations con

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Batista, Ana Carla Schiavinato. "A (não)diretividade pedagógica na educação a distância." Universidade Federal de São Carlos, 2013. https://repositorio.ufscar.br/handle/ufscar/2659.

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Made available in DSpace on 2016-06-02T19:39:33Z (GMT). No. of bitstreams: 1 5059.pdf: 899945 bytes, checksum: 39caf1fefbf2aca53ad119d52f92bea4 (MD5) Previous issue date: 2013-03-04<br>Financiadora de Estudos e Projetos<br>This search presents a subject that is on top of the currently education scenario, the Distance Education. This new education mode that comes as a promess to breaking barriers of timing and space, still have many things to say about their real consequences regarding education of the individual. Thus arises the importance of this research which aims investigating issues rel

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Pavasovic, Vladimir, and vpavasovic@wmgacoustics com au. "The radiation of Sound from Surfaces at Grazing Angles of Incidence." RMIT University. Applied Sciences, 2006. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20060911.115939.

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It is difficult to predict the sound radiation from large factory roofs. The existing infinite panel theories of sound insulation are not sufficient when the sound radiates at grazing angles. It has been shown that the reason for the collapse of the theory is the well known result for the radiation efficiency. This research will present a simple analytic strip theory, which agrees reasonably well with numerical calculations for a rectangular panel. Simple analytic strip theory has lead to the conclusion that it is mainly the length of the panel in the direction of radiation, rather than its

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Ma, Hua. "Localisation de sources par méthodes à haute résolution et par analyse parcimonieuse." Phd thesis, Université de Franche-Comté, 2011. http://tel.archives-ouvertes.fr/tel-00839142.

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Cette thèse a pour but d'estimer la position et la puissance de sources sonores ponctuelles à l'aide d'une antenne acoustique. Nous nous intéressons d'abord à la directivité des antennes acoustiques pondérées. On montre qu'une telle antenne, appelée antenne conventionnelle, même si elle est à directivité optimale, est inutilisable pour localiser plusieurs sources sonores. Des traitements adaptatifs d'antenne sont donc exigés et les méthodes dites à haute résolution sont introduites. Elles sont basées sur l'estimation de la matrice de covariance des signaux issus des capteurs et présentent l'av

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Goncharova, Iuliia. "Investigation of a small-sized omnidirectional antenna." Thesis, Linnéuniversitetet, Institutionen för datavetenskap, fysik och matematik, DFM, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-17835.

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The purpose of this research is to find ways to create an omnidirectional antenna with high directivity in the vertical plane. The investigation is based on computer simulation using the program CST 2011. The objective is a narrow-band antenna that is omnidirectional in the horizontal plane and has maximum achievable directivity for a fixed size. Three of the most promising antenna designs are selected based on the current state of antenna technology. Their maximum directivities are estimated by means of well known relations in antenna theory. It is shown that the most suitable design is an om

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Raetz, Samuel. "Développement de méthodes numériques pour l’imagerie de sources optoacoustiques en milieu solide." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14624/document.

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L’objectif de ces travaux est le développement d’une méthode d’imagerie de sources optoacoustiques en milieu solide. Afin d’analyser l’influence de la géométrie de la source sur les ondes acoustiques qu’elle génère et ainsi prévoir qualitativement si l’image de la source peut être obtenue avec une précision suffisante, la directivité d’une source acoustique est d’abord considérée. Pour quantifier plus précisément cette influence, la résolution complète de la propagation des ondes générées par cette source est ensuite menée. L’analyse de l’influence de l’incidence oblique d’un faisceau laser lo

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Hickling, Christopher John. "Inhomogeneous, Anisotropic Turbulence Ingestion Noise in Two Open Rotor Configurations." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/100637.

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Two rotor configurations with different non-uniform inflows were studied: a rotor ingesting the wake of an upstream cylinder and a rotor ingesting a thick axially symmetric boundary layer from an upstream centerbody. In both cases, the undisturbed inflow was measured without the rotor present in order to characterize the inflow, in particular to calculate the unsteady upwash velocity distribution at the location of the rotor. In addition, detailed acoustic measurements were completed using a 251-channel large-area microphone array. In all, over 400 conditions covering different advance rati

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Olsson, Mikael, and Anders Söderberg. "Design guideline for audible warning signal and determination of sound pressure characteristics : Second version." Thesis, Örebro universitet, Akademin för naturvetenskap och teknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:oru:diva-19412.

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Today Atlas Copco Rock Drills AB hasn’t got any method to determine how many warning alarms they need on their machines and how they should be mounted to use their full potential. At the moment a travel alarm is usually placed in the front of the machine and a reverse alarm in the back. Then a measurement of the sound pressure level around the machine is performed to see if it is enough to pass the limit according to different ISO-standards. Otherwise they have to mount some extra alarms and then do the measurements again until the standards are fulfilled. The aim of this thesis work is to dev

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Baleshan, Tharunie. "Analysis of distributed beamforming in cooperative communications network with phase shifter based smart antenna nodes." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/84539/1/Tharunie_Baleshan_Thesis.pdf.

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This research study investigates the application of phase shifter-based smart antenna system in distributed beamforming. It examines the way to optimise the transmit power by jointly maximising the directivity of the array antennas and the weight vector for distributed beamforming. This research study concludes that maximising directivity can lead to better transmit power minimisation compared to maximising field intensity. This study also concludes that signal to noise power ratio maximisation subject to a power constraint and power minimisation subject to a signal to noise power ratio constr

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Demontis, Hugo. "Identification de sources acoustiques complexes en milieu réverbérant par grands réseaux de microphones." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS196.

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La directivité d'une source sonore intervient dans de nombreuses applications en acoustique, allant de la compréhension des phénomènes physiques aéro-acoustiques jusqu'à la reproduction sonore spatialisée. Pour estimer expérimentalement cette signature spatiale, il est d’usage de déployer les microphones de sorte à englober partiellement ou totalement les sources. Le rayonnement acoustique est ainsi capté dans toutes les directions de l'espace. Sur ce principe, nous proposons dans ce manuscrit le développement d'un réseau microphonique 3D de grandes dimensions. L'antenne baptisée MODO ("Les Mu

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Lardies, Joseph. "Etude d'antennes acoustiques a directivite constante sur une large bande." Toulouse 3, 1987. http://www.theses.fr/1987TOU30214.

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Cette etude porte sur la conception et la realisation d'antennes acoustiques a largeur de faisceau constante sur une large bande. On examine deux techniques, dont l'une est basee sur un reseau d'antennes maintenant la largeur du lobe principal constant sur plusieurs octaves, tandis que l'autre methode permet de maintenir la largeur du faisceau d'une antenne constante sur plusieurs octaves. Etude de l'estimation de la direction et de la puissance de signaux acoustiques en vue d'applications possibles

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Boissinot, Philippe. "Impedance acoustique de rayonnement dans les antennes planes : impedances mutuelles avec un milieu de propagation de type viscoelastique et application aux directivites d'antenne." Paris 6, 1988. http://www.theses.fr/1988PA066092.

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Chen, Yang-Ming, and 陳陽明. "Humane Directivity Point System." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/gb8rc6.

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碩士<br>國立高雄應用科技大學<br>電子工程系碩士班<br>104<br>ABSTRACT Taiwan high degree of urbanization, Three-quarters of the people live in 31% of the land area. The population density per square kilometer up to 1551.6 people, causing traffic accidents occur frequently. When traffic accidents, resulting in a high proportion of deaths of pedestrians. In recent years the proportion of pedestrian injuries decreased. In recent years the proportion of pedestrian injuries decreased. The reason is that a significant increase in traffic accidents. Resulting in the relative decline in the proportion of pedestrian injurie

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Spagnuolo, E. "Fault Directivity and Seismic Hazard." Thesis, 2010. http://hdl.handle.net/2122/10121.

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In planning the design of structures in a region of potential seismic activity, a specification of the “strength” of the earthquake ground motion, or the most likelihood ground motion level, is needed. The earthquake occurrence, and its effects, is described as a stochastic process. Thus its realization is linked to state variables defined over a a known space through a continuous function. The Ground Motion Predictive Equation (GMPE) realize this function and, despite its shortcoming as an effective design tool to control damage (Priestly, 2003), it is still the most widely used representatio

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