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 81 for “"Linear Array"”.
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Optimal linear array heading in a directional noise field
… the signal-to-noise ratio (SNR) detected by a linear array in a directional ambient noise field. The SNR can be optimized by minimizing the ambient noise detected by the array. For a given target location, each possible heading of the array centers the ambiguous beam of the array at a different …
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Photoacoustic Microscopy and Photoacoustic Computed Tomography Using High-frequency Linear Array Ultrasonic Transducers
… imaging depth in tissue by employing ultrasonic array detectors and inverse algorithms. This dissertation aims to improve the functionality of OR-PAM using a high-frequency linear ultrasonic array, and to advance the performance of linear-array PACT to full view angle capability and higher …
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Optical Analysis of a Linear-Array Thermal Radiation Detector for Geostationary Earth Radiation Budget Applications
… detector consists of a thermopile linear array thermal radiation detector. The principal objective of this research is to develop an optical model for the detector and its cavity. The model based on the Monte-Carlo ray-trace (MCRT) method, permits parametric studies to optimize the …
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Horizontal linear array sensor localization and preliminary coherence measurements from the 2001 ASIAEX South China Sea experiment
… 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. Therefore, to maximize the efficiency of an array, the size …
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Analytical and Experimental Characterization of a Linear-Array Thermopile Scanning Radiometer for Geo-Synchronous Earth Radiation Budget Applications
… The radiometer consists of a 256-element linear-array thermopile detector mounted on the wall of a mirrored wedge-shaped cavity. The objective of this research is to provide analytical and experimental characterization of the proposed radiometer. A dynamic end-to-end opto-electrothermal …
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Passive monitoring of high-intensity focused ultrasound
… was employed using beamforming approaches and a linear array system co-aligned with the HIFU source. The passive array made use of the weakly scattered signal from the medium to reconstruct the field pattern of the HIFU field in the medium. The focus of a 6 MHz single-element transducer (f/3) was …
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The Communication Complexity of Distributed Computing and a Parallel Algorithm for Polynomial Roots
… derived by simulating the general network by a linear array and then using a lower bound on the communication complexity of the problem on the linear array. Applications of this technique yield nontrivial optimal or near-optimal lower bounds on the communication complexity of distinctness, …
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Phased Array Beamsteering in Composite Laminates for Guided Wave Structural Health Monitoring
<p>In this study a guided wave phased array beamsteering approach is applied to composite laminates. Current beamsteering algorithms derived for isotropic materials assume omnidirectional wave propagation. Due to inherent anisotropy in composites, guided wave propagation varies with direction and …
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Phased Array 802.11g Antenna
… involves the development of a 2.4GHz phased array antenna for consumer wireless applications. 802.11g specifications include 11 channels from 2.412 GHz to 2.472 GHz. Each channel has a 22MHz minimum bandwidth with a 5 MHz center-to-center interchannel spacing. Design goals for the phased …
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Exploring potential mechanisms responsible for observed changes of ultrasonic backscattered energy with temperature variations
… The simulations were carried out with a linear array having 128 elements and center frequency of 5.5 MHz. Experiments were carried out by scanning physical phantoms containing randomly spaced glass beads with a Sonix RP scanner at every 0.5 ºC from 37 ºC to 48 ºC. Shifts in the …
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Imaging the crust and uppermost mantle of north central Alaska using the joint inversion of ambient seismic noise correlation and receiver function
… mainly of the temporarily deplored ARTIC seismic array from mid 2005 to mid 2007. This linear array runs north from Fairbanks, AK to Prudhoe Bay, AK. The source for the surface wave tomography is ambient seismic noise correlation, which correlates the background noise from a seismic station’s …
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Aeroacoustic Study of a Model-Scale Landing Gear in a Semi-Anechoic Wind Tunnel
… out using both a 63-elements microphone phased array and a linear array of 15 microphones. The noise sources were identified from the flyover view under various flow speeds and the phased array positioned in both the near and far-field. The directivity pattern of the landing gear was determined …
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Wideband planar array antennas: theory and measurements
The need for a wide bandwidth array is introduced and explained. Basic planar array principles are reviewed as well as previous work performed on wide bandwidth planar array design. An Archimedean spiral is suggested for the array element and a model for the element radiation pattern is presented. …
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Syntheses of Dimensionally Altered Enzyme Substrates by Means of the Finkelstein Reaction (Benzopurine, Naphthopurine)
… commenced with 5,6-dimethylbenzimidazole and the linear array of rings was constructed by means of the Finkelstein reaction. lin-Naphthoadenosine was synthesized by ribosidation of 9-methylthiobenzimidazo{5,6-g}quinazoline followed by ammonia displacement. Syntheses of …
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Latency Study and System Design Guidelines for Cooperative LTE-DSRC Vehicle-to-Everything (V2X) Communications including Smart Antenna
… better in a dynamic propagation environment. A linear array antenna can perform dynamical appropriate azimuth pattern by having different weights of each element. The later section includes (1) identifying beam pattern parameters based on locations of a vehicular transmitter and fixed receivers …
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Transitive Inference and Commonly Coded Stimuli
… were associated with one another along the linear array. For the Within Common Coding Group, the outcomes were arranged so that B and D both received the same outcome (when positive in their respective pairs). For the Between Common Coding Group, the outcomes were arranged so that B and D …
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A Bayesian Approach to Beamforming for Uncertain Direction -of -Arrival
… by the signal-to-noise ratio (SNR) of the array. Three efficient implementation algorithms for the Bayesian beamformer are developed by exploiting the structure of the steering vector of a uniform linear array (ULA). Each algorithm is analogous to a conventional filter design technique. The …
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A real-time optical measurement system
… ability of the algorithms to find a target on a linear-array charge-coupled device (CCD) camera are performed. The running maximum algorithm provides the best accuracy and speed and therefore is recommended. A real-time architecture to implement the running maximum algorithm is developed. The …
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Digitally controlled microstrip phased array.
Adaptive phased arrays are versatile sensors which adjust themselves automatically and electronically to meet particular constraints. Such a constraint might be to minimise the level of interference or to enhance the desired signals or both simultaneously. This enhanced system performance. These …
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CAPACITY ENHANCEMENT OF CDMA SYSTEM USING ANTENNA ARRAY
… multiple access (CDMA) system with uniform linear array (ULA) at the base station (BS) [1 - 3]. An overall system outage probability is proposed as a capacity performance measure for multirate CDMA system with different service requirements among users. In this thesis, the performance …
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