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.
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Showing 1 to 20 of 21 for “"array geometry"”.
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Capturing spatial audio from arbitrary microphone arrays for binaural reproduction
… been recorded from specialized microphone arrays that are too expensive and unwieldy to incorporate into today's consumer devices. Consumer devices, such as mobile devices, typically use cheap microphones with strict limitations on array geometry. Therefore, in order to capture spatial …
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A beam pattern design procedure for multidimensional sonar arrays employing minimum variance beamforming
… for general multidimensional irregular sonar arrays that incorporates the not well understood effects of array geometry into the design process. The procedure is implemented by generating a "penalty function" in a spectral covariance function form. Processing the penalty function causes beam …
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Enhanced flow boiling heat transfer in microchannels with structured surfaces at varied mass flow rates
… in microchannels with surface micropillar arrays. The motivation for this investigation was to determine the general trends of the optimal micropillar array geometry in terms of its heat transfer capabilities. The experiment was conducted with three microchannels: a flat surface …
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Kurtosis-based blind beamforming: an adaptive, subband implementation with a convergence improvement
… of background noise using a multi-microphone array. Without knowledge of the array geometry, talker location, or the room response, many traditional beamforming techniques cannot be used effectively. An adaptive, maximum-kurtosis objective is used in the frequency domain to blindly enhance the …
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Manufacturing and analysis of a LIGA heat exchanger for the surface of a tube: a cooling simulation of the leading edge region of a turbine blade
… fin heat exchanger are described. The pin fin array geometry investigated is staggered, with pin diameters of 500 ¦Ìm, height to diameter ratios of 1.0 and spacing to diameter ratios of 2.5. Pressure loss and heat transfer experimental results for 4,000¡ÜRe¡Ü20,000 are reported and a Nu-Re …
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Accuracy and resolution in 2D resistivity inversion
… inverse problem. The insensitivity of surface array data to deeper targets typically presents an under-determined problem for solution by the inversion algorithm, and the smoothing function within the algorithm tends to "smear" tomographic imagery. Together, the physical challenges of …
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Development of MRI-compatible Transducer Array for Focused Ultrasound Surgery: : The Use of Relaxor-based Piezocrystals
… limited availability of experimental ultrasound array sources and multichannel electronics able to drive them hinder the research into FUS system configurations for patient conditions such as breast cancer. <br/>The work in this dissertation explored the development of ultrasound arrays for MRI …
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Exploring data compression for a distributed aerial relay application
Beamforming systems typically involve arrays of antenna elements with controllable spacing and little or no motion. However, a distributed beamforming system could leave array geometry and motion largely unconstrained. This work considers an airborne relay communication concept with multiple …
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Binaural Hearing Effects of Mapping Microphone Array's Responses to a Listener's Head-Related Transfer Functions
… thesis focuses on the mapping of the microphone array’s response to match the characteristics of a human subject’s Head-Related Transfer Function (HRTF). The mapping of the response is first explored with a ‘monaural HRTF matching’ that filters the response independent of the arrival angles. For …
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Thermal hydraulic analysis of hydride fuels in BWR's
… operate at the highest possible power. This fuel geometry is found out of hundreds of possible choices by using a script to automate a parametric study. A similar process was completed by an MIT graduate student for PWR reactors. While this thesis demonstrates the ability to use such a method for …
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Comparison of Machine Learning-Based Methods for Narrowband Blind Adaptive Beamforming
… assumed prior knowledge of the receive array geometry and of the incoming signal directions. This information is normally found via array calibration. Blind source separation methods do not require this information and therefore are more robust to array calibration errors. Traditional …
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Array signal processing for source localization and enhancement
<p>“A common approach to the wide-band microphone array problem is to assume a certain array geometry and then design optimal weights (often in subbands) to meet a set of desired criteria. In addition to weights, we consider the geometry of the microphone arrangement to be part of the optimization …
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Aerodynamic Force and Pressure Loss Measurements on Low Aspect Ratio Pin Fin Arrays
… of internal cooling channels fitted with pin fin arrays serves as one method of accomplishing this goal. Consequently, the addition of pin fin arrays comes at the expense of increased pressure drop. Therefore the pin fin geometry must be judiciously chosen to achieve the required heat transfer …
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Analysis And Modeling Of The Eds Maglev System Based On The Halbach Permanent Magnet Array
… / space launch assist system. The Halbach array due to its unique magnetic field feature has been widely used in various applications. The EDS system using Halbach arrays leads to the potential EDS system without super-conductor (SC) technology. In this thesis, the Halbach array magnetic …
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Design and Implementation of System Components for Radio Frequency Based Asset Tracking Devices to Enhance Location Based Services. Study of angle of arrival techniques, effects of mutual coupling, design of an angle of arrival algorithm, design of a novel miniature reconfigurable antenna optimised for wireless communication systems
… sources plays a vital role in the field of array signal processing as MIMO systems can be employed at both the transmitter and the receiver end and the system capacity, reliability and throughput can be significantly increased by using array signal processing. Almost all applications require …
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Development of ZnO Nanotube Arrays for Chemical Sensing
… of a new material, anodic ZnO nanotube array, as the sensing platform and the application of artificial intelligence to a sensor system developed using this material. The nanotube array geometry showed specific light scattering properties, as revealed by the finite difference time domain …
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Interference Mitigation by Reconfigurable Adaptive Antenna Array
Antenna arrays play an important role in diverse application areas, such as target detection and direction of arrival (DOA) estimation to list a few. Traditional receiver structures with a fixed array configuration are either inefficient due to array redundancies or may incur significant …
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Reconfigurable Resonant Cubic HF Phased Array for In-Space Assembly Operation
Conventional two-dimensional phased arrays face two major shortcomings: the presence of ambiguities in direction of arrival measurements and beam broadening endfire effects. The literature provides methods for addressing and minimizing these problems on conventional planar phased array structures, …
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Wireless Sensing and Fusion using Deep Neural Networks
… occupancy sensing. Finally, in the context of array processing, we solve the Model order estimation (MOE) problem, a prerequisite for Direction of Arrival (DoA) estimation in the presence of correlated multipath, a well-known difficult problem. Due to the limits imposed by array geometry, it is …
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Sviluppo di metodologie di localizzazione nel contesto del Comprehensive Nuclear Test-Ban Treaty
… of very low magnitude recorded by a trypartite array at a very local scale. For the two above-mentioned techniques, we have used the crosscorrelation technique among digital waveforms in order to minimize the errors linked with incorrect phase picking. The cross-correlation method relies on the …
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