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 17 of 17 for “"acoustic array"”.
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A tomographic ocean sound speed profile from a long veritcal acoustic array
… northeast Pacific ocean is obtained using Ocean Acoustic Tomography, from data acquired during the 1987 SVLA experiment on a long (900 m) 120 hydrophone vertical acoustic array. In particular, we pulse compress the received signal with a phase-only matched filter. The signal, centered at 80Hz, is …
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Evaluation by simulation of an acoustic array composed of multiple autonomous vehicles
Ship-towed arrays have been integral to Navy combatant operations for many decades. The continual advancement of towed array technology has been continually driven by the need for high sensitivity, low self-noise, and response across a wide range of frequencies. Robotic autonomy, as applied to …
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Sound Propagation via Narrow Beam Audio Projection
The parametric acoustic array is a nonlinear phenomenon of physics theoretically described over fifty years ago. It consists in the generation of secondary sound waves by the propagation of two collimated primary ultrasonic waves at a close frequency. The sound wave generated corresponds to the …
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Acoustic travel time perturbations due to an internal tide and internal wave field in the Barents Sea
… loggers on the southwest mooring of the array. Modal perturbations in acoustic pulse travel time and the travel time covariance are calculated and compared for consistency to a simple ray model. These perturbations are small for the modal arrivals that the vertical acoustic array which …
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Efficient localization in a dispersive waveguide : applications in terrestrial continental shelves and on Europa
… and environmental parameter estimation in seismo-acoustic waveguides by exploiting the dispersive behavior of guided wave propagation. The methods developed are applied to the terrestrial continental shelf environment and the Jovian icy satellite Europa. The thesis is composed of two parts. First, …
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Design and experimental evaluation of an Autonomous Surface Craft to support AUV operations
… two modems together in a short baseline acoustic array. Results of this tracking show less than four meters of error under difficult real-world test conditions.
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Vertical axis wind turbine acoustics
… measurements were carried out using the phased acoustic array in the closed section Markham wind tunnel at Cambridge University Engineering Department. Beamforming was used in conjunction with analysis of the measured sound spectra in order to locate and identify the noise sources on the VAWT …
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Horizontal linear array sensor localization and preliminary coherence measurements from the 2001 ASIAEX South China Sea experiment
… component of the 2001 Asian Seas International Acoustic Experiment (ASIAEX), where a fixed Horizontal Linear Array (HLA) was deployed to study transverse array coherence in a coastal environment. Arrays obtain their gain and directivity by coherently adding the energy that impinges on them. …
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Gulf Sturgeon (<i>Acipenser oxyrinchus desotoi</i>) Pre-Restoration Occupancy Patterns on Ship Island, Mississippi Sound with an Evaluation of Designated Critical Habitat Use by Eastern and Western Population Segments
… habitat monitored by the Ship Island (SI) acoustic array during overwintering periods from 2011 to 2015 prior to MsCIP SI restoration. An occupancy index analyzed patterns of spatial and temporal habitat use of both western and eastern population segments (WPS and EPS, respectively) of GS …
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The rise and fall of the spiny lobster (Jasus edwardsii) in the Hauraki Gulf, northeastern New Zealand
… Point (CROP) marine reserve with a passive acoustic array, and carrying out feeding assays to determine the ability of J. edwardsii to consume C. rodgersii, and its preference for another barren-forming sea urchin, Evechinus chloroticus. Lobster densities in three marine reserves and their …
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Slat aerodynamics and aeroacoustics with flow control
… study primarily investigated the flow and aeroacoustics associated with the slat of a three-element aerofoil in approach conditions. The study assessed importance of several factors and examined their aerodynamic impacts. The factors investigated were aerofoil incidence, slat angle, slat cusp …
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Localization of Dynamic Acoustic Sources with a Maneuverable Array
… spatial spectrum estimation with maneuverable arrays. Two applications, each having different environmental assumptions and array geometries, are considered: 1) passive broadband source localization with a rigid 2-sensor array in a shallow water, multipath environment and 2) time-varying …
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The Impact of Three Dimensional Flow Anisotropy and Transients on Turbulence Ingestion Noise in Open Rotors
… of the sound. Measurements of the sound using an acoustic array showed directivity effects that resulted from the location of the embedded shear layer and rollup vortices. Although the vortices likely have some effect on the spectra, most of the noise is dominated by the turbulence ingestion of …
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Adaptive matched field processing in an uncertain propagation environment
Adaptive array processing algorithms have achieved widespread use because they are very effective at rejecting unwanted signals (i.e., controlling sidelobe levels) and in general have very good resolution (i.e., have narrow mainlobes). However, many adaptive high-resolution array processing …
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Delination of Coastal Shark Habitat within North Carolina Waters Using Acoustic Telemetry, Fisher-Independent Surveys, and Local Ecological Knowledge
… using fishery-independent means. Catch data and acoustic telemetry were used to assess shark habitat at the coastal nearshore scale. Sharks captured near Cape Hatteras could be grouped into warm water and cold water assemblages. Juvenile Dusky (Carcharhinus obscurus) and Sandbar (Carcharhinus …
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Incorporating Migration and Local Movement Patterns into Management Strategies for Spiny Dogfish (Squalus acanthias)
… in dynamic environments through the use of acoustic telemtry. Approximately 30 percent of papers reviewed had no details on design specifications. Meta-analyses suggest that more fish were redetected when more acoustic equipment was deployed for longer periods of time, exemplifying the need …
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Architectures for e-Textiles
… (e-textile) hardware prototype, a large-scale acoustic beamformer, provides a basis for the simulator and offers experience in building these systems. The contributions of this research focus on defining the electronic textile architecture, creating a simulation environment, defining a …