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 26 for “"Acoustic Waveguide"”.
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Instantaneous continental-shelf scale sensing of cod with Ocean Acoustic Waveguide Remote Sensing (OAWRS)
… and fishing consortiums were made for an Ocean Acoustic Waveguide Remote Sensing (OAWRS) survey of the Gulf of Maine cod stock. Typically, cod stock assessments incorporate data collected from conventional acoustic and trawl line transect surveys that highly undersample the marine environment in …
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Remote sensing of submerged objects and geomorphology in continental shelf waters with acoustic waveguide scattering
… The conditions necessary for scattering in a waveguide to become diffuse is derived directly from Green's Theorem. Simulations with the unified model indicate that the detection of submerged target echoes above diffuse seafloor reverberation is highly dependent upon waveguide properties, …
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Spectral discrimination of fish shoals from seafloor in the Gulf of Maine during the ocean acoustic waveguide remote sensing (OAWRS) 2006 experiment
… dependence of all pixels in an examined ocean acoustic waveguide remote sensing (OAWRS) image.
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Acoustic Frequency Domain Reflectometry
Acoustic Frequency Domain Reflectometry (AFDR) is a novel technique employing frequency modulated continuous wave (FMCW) methods in solid acoustic waveguide reflectometry. It is particularly suited to dispersion compensation and phase compensation due to the measurement domain being the frequency …
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Elastic sandwich problem: ocean acoustics in Arctic environments
… ice layer as the upper boundary of the ocean acoustic waveguide and an elastic half-space seafloor as the lower boundary. An analytic normal mode solution for the problem of ocean acoustic propagation in this waveguide is found and then simulated numerically. The solution is benched marked …
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The effect of attenuation from fish on long-range active and passive acoustic sensing in the ocean
Attenuation from fish can reduce the intensity of acoustic signals and significantly decrease detection range for long-range active and passive sensing in the ocean. This makes it important to understand the relevant mechanisms and accurately predict attenuation from fish in underwater acoustic …
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The Effect of Attenuation from Fish on Long-Range Active and Passive Acoustic Sensing in the Ocean
Attenuation from fish can reduce the intensity of acoustic signals and significantly decrease detection range for long-range active and passive sensing in the ocean. This makes it important to understand the relevant mechanisms and accurately predict attenuation from fish in underwater acoustic …
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Multichannel blind deconvolution in underwater acoustic channels
… problem and implemented these techniques in acoustic waveguide multiple environment. We developed a systematic way to build an efficient and accurate channel models incorporating a priori information about the expected Channel Impulse Responses' (CIRs) arrival-time structure. Based on the …
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Exploration of liquid crystal polymer packaging techniques for rf wireless systems
… are then utilized for the demonstration of bulk acoustic waveguide (BAW) filter applications and for the realization of highly integrated phased-array antenna systems.
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The effect of internal waves on long range acoustic propagation in the ocean
The acoustic-internal wave interaction in an acoustic waveguide is investigated using wave techniques. Refractive index fluctuations due to the vertical displacements of the internal waves create an inhomogeneous waveguide. The analysis uses weak scattering theory based upon the Rytov perturbation …
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Performance bounds on matched-field methods for source localization and estimation of ocean environmental parameters
… parameters by exploiting full wave modeling of acoustic waveguide propagation. Typical estimation performance demonstrates two fundamental limitations. First, sidelobe ambiguities dominate the estimation at low signal-to-noise ratio (SNR), leading to a threshold performance behavior. Second, …
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Study of waveguide and anisotropy effects upon surface acoustic wave velocities in thin films
… on laser excitation and detection of surface acoustic waves (SAWs) for mechanical properties of thin metal films in the microelectronic industry. In this work, the effect of elastic anisotropy from silicon wafers on ISTS measurements has been studied. It has been shown that for films of …
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Performance bounds on matched-field methods for source localization and estimation of ocean environmental parameters
… parameters by exploiting full wave modeling of acoustic waveguide propagation. Typical estimation performance demonstrates two fundamental limitations. first, sidelobe ambiguities dominate the estimation at low signal-to-noise ratio (SNR), leading to a threshold performance behavior. Second, …
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Acoustic data communication system for in-pipe wireless sensor networks
… unit, it is proposed to use the pipeline as an acoustic waveguide for the transmission of appropriately modulated acoustic waves that encapsulate the digital data, since radio frequency transmission is not feasible underground. The confined acoustic channel imposes severe distortion on the …
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Fish population and behavior revealed by instantaneous continental-shelf scale imaging
… over thousands of square kilometers using Ocean Acoustic Waveguide Remote Sensing (OAWRS) is demonstrated with data from its first implementation in a 2003 field experiment off the US Continental Shelf south of Long Island, NY. Conventional methods for monitoring fish populations rely on …
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Analysis of acoustic propagation in the region of the New England continental shelfbreak
During July and August of 1996, a large acoustics/physical oceanography experiment was fielded in the Mid-Atlantic Bight, south of Nantucket Island, MA. Known as the Shelfbreak Front PRIMER Experiment, the study combined acoustic data from a moored array of sources and receivers with very high …
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Analysis of acoustic propagation in the region of the New England continental shelfbreak
During July and August of 1996, a large acoustics/physical oceanography experiment was fielded in the Mid-Atlantic Bight, south of Nantucket Island, MA. Known as the Shelfbreak Front PRIMER Experiment, the study combined acoustic data from a moored array of sources and receivers with very high …
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Acoustic Waveguides and Sensors for High Temperature and Gamma Radiation Environment
… are reported, such as optical fiber sensors and acoustic sensors, they all have drawbacks. In this dissertation, fused quartz and sapphire acoustic waveguides and sensors are developed for high temperature and heavy gamma radiation. The periodic structure, acoustic fiber Bragg grating (AFBG), is …
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Tracking and speed evaluation of cod schools in the 2014 Nordic Seas experiments
… by conventional methods such as echosounders and acoustic tagging of fish, which are only able to track one or a few schools at a time with low spatial sampling. In 2014, the Ocean Acoustic Waveguide Remote Sensing system (OAWRS) was employed in the Nordic Seas for the study of fish shoal behavior …
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Mean, variance, and temporal coherence of the 3D acoustic field forward propagated through random inhomogeneities in continental-shelf and deep ocean waveguides
When an acoustic field propagates through a multimodal waveguide, the effect of variations in medium properties induced by 3D random inhomogeneities accumulates by multiple forward scattering over range. This causes significant random fluctuations in the received field and greatly affects …
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