Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 16 of 16 for “"Ray-tracing Model"”.
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The mid-latitude ionosphere under quiet geomagnetic conditions: propagation analysis of SuperDARN radar observations from large ionospheric perturbations
… conditions. First, we seek to establish a better model of HF propagation effects on SuperDARN observations. To do so, we developed a ray-tracing model coupled with the International Reference Ionosphere (IRI). This model is tested against another well established ray-tracing model, then optimized …
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RF-Based Indoor Localization Around Corners
… past RF-based proposals rely on a simplistic ray-tracing model that fails in practical indoor scenarios. This thesis introduces CornerRadar, an RF-based method that provides accurate around-corner indoor localization. CornerRadar addresses the limitations of the ray-tracing model used in past …
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A matched field processing approach to long range acoustic navigation
… high-multipath environment. The system uses a ray tracing model of sound propagation in a horizontally stratified ocean to associate each multipath arrival with a particular ray path through the ocean. This ray path identification allows an inversion for both vehicle position and sound speed …
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Simulating high flux solar radiation and assessing its influence on a sooty flame
… gap. High flux solar simulators, comprising an array of high-intensity-discharge lamps coupled with elliptical reflectors, have been widely employed to study concentrated solar thermal energy systems. The use of electrical solar simulators holds the advantage over natural solar radiation in …
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Biofilm Control Inside Secondary Water Storage Containers Using UV LIght
… in humanitarian contexts. To address this gap, a ray tracing model was developed to simulate UV irradiance distribution within a representative jerry can, and experimental validation showed model predictions were within 17% of measured values. Lab-grown biofilms were then treated at locations …
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Forward sound propagation around seamounts : application of acoustic models to the Kermit-Roosevelt and Elivs seamounts
… by the seamounts. A towed hydrophone array, with 64 sensors cut for 250Hz (3m spacing), was used to measure the signals transmitted from the aforementioned broadband sources at many locations around the Kermit-Roosevelt and Elvis seamounts. Utilizing the measured broadband signals from …
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Design of a 5 Degree of Freedom Kinematic Stage for the Dual Crystal Backlighter Imager Diagnostic
… crystal backlighter imager (CBI), allows for X-ray imaging of the target at late stages of its implosion.</p> <p>The aim of this project was to increase the current capabilities of the CBI diagnostic with the addition of a second crystal. This thesis focuses on the design development of the 5 …
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Site-specific propagation prediction for wireless in-building personal communication system design
This dissertation describes a geometrical optics model to predict propagation in buildings for personal communication system (PCS) design. Background on the growth of wireless communications is given, and the importance of accurate propagation models is discussed. The peculiarities of propagation …
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Prediction of sound pressure and intensity fields in rooms and near surfaces by ray tracing
… unwanted acoustical problems. Prediction models are often used to find the most cost-effective solution to a given acoustical problem. The accuracy of sound-field prediction varies with the particular model, as do the parameters predicted. Most models only predict sound-pressure levels. …
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Stochastic acoustic ray tracing with dynamically orthogonal equations
Developing accurate and computationally efficient models for ocean acoustics is inherently challenging due to several factors including the complex physical processes and the need to provide results on a large range of scales. Furthermore, the ocean itself is an inherently dynamic environment …
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The Influence of Obliquely Propagating Monsoon Gravity Waves on the Polar Summer Mesosphere
… waves is not included in the present global models. Understanding the influence of the obliquely propagating monsoon gravity waves on the polar summer mesosphere, as well as the hemispheric and seasonal variations of this phenomenon, can improve the gravity-wave parameterization schemes used …
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Forward sound propagation around seamounts : application of acoustic models to the Kermit-Roosevelt and Elvis seamounts
… by the seamounts. A towed hydrophone array, with 64 sensors cut for 250Hz (3m spacing), was used to measure the signals transmitted from the aforementioned broadband sources at many locations around the Kermit-Roosevelt and Elvis seamounts. Utilizing the measured broadband signals from …
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GPS augmentation using digital spatial data
… to the fact that higher accuracy digital surface models (DSMs), which include buildings and vegetation, and digital maps, have only been made widely available in recent years.<br/><br/>This thesis will report on a number of experiments that used spatial data of various complexity and accuracy for …
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Enhancing Signal Coverage for UHF RFID Systems
… a combination of antenna design, mathematical modelling and algorithm development. A novel UHF RFID reader antenna with 2D beam-scanning ability, a wide axial ratio (AR) beamwidth and tunable polarisation performance is designed, simulated, measured and tested in Chapter 3 of this thesis. It is …
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Ultra thin micro solar cells with concentration optics: fabrication, modeling and characterization
… for certain applications. A micro solar cell array module was thus developed to overcome these limitations and provide a cheap and compact solution. By miniaturizing the solar cells to produce micro-scale solar cells, several advantages can be achieved. The micro solar cell enables a distributed …
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Impacts of short-time scale water column variability on broadband high-frequency acoustic wave propagation
… of acoustic beams and refraction of acoustic rays. This study focuses on high-frequency broadband acoustic waves, and examines the influence of short-time scale water column variability on broadband high-frequency acoustics, wavefronts, from 7 to 28 kHz, in shallow water. Short-time scale …