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 28 for “"small aperture"”.
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Investigating Exoplanets and Transients Using Small-Aperture Telescopes
… well as assessing the usefulness and impact of a small-aperture semi-autonomous facility in Mallorca for exoplanet studies and studies of transient sources. Additionally, a method for exploring the Roche lobe of an exoplanet and the effects this has on the shape and density of the planet is also …
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Orbital Determination Feasibility of LEO Nanosatellites Using Small Aperture Telescopes
… orbit using a Meade LX600-ACF 14” diameter aperture telescope currently located on the California Polytechnic State University campus. The optical telescope is fitted with an f/6.3 focal reducer, SBIG ST-10XME CCD camera and Optec TCF-S Focuser. This instrumentation allowed for a 22’ X 15’ …
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Space Image Processing and Orbit Estimation Using Small Aperture Optical Systems
… awareness (SSA) data has never been greater. Small aperture (< 0:5m) optical systems, increasingly popular in both amateur and professional circles, provide an inexpensive source of such data. However, utilizing these types of systems requires understanding their limits. This research uses a …
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Software simulation of depth of field effects in video from small aperture cameras
… of the effect (such as the amount of defocus, aperture shape, and defocus plane) and allows the effect to be used even on hardware which would not typically allow for depth of field. In addition, because it is a completely post processing technique and requires no change in capture method or …
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An Investigation of a Digital Bearing Computer for a Small Aperture Radiodirection Finding System
Made available in DSpace on 2014-12-08T22:23:47Z (GMT). No. of bitstreams: 1 6511790.pdf: 4042738 bytes, checksum: cd5092ad30e6e65669c2cb15c9cc690d (MD5) Previous issue date: 1965
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DSSS detection and direction finding methods for a DSP-based small aperture DF system
This dissertation discusses an investigation into methods for detection and direction finding of direct-sequence spread-spectrum signals (DSSS), appropriate for a particular DSP-based direction finding platform. Relevant details on DSSS and radio direction finding are presented. These are used as …
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Planetary Seismology using Single-Station and Small-Aperture Arrays: Implications for Mars and Ocean Worlds
… investigated how single-station seismometers and small-aperture seismic arrays in analog settings can quantify instrument capabilities, develop methodologies to detect and locate seismicity, and constrain internal structure. First, I used a single-station seismometer in Germany to study how the …
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Transport of elliptic intense charged -particle beams
… associated with the high space charge and small-aperture structure is addressed, and a novel transport theory of large-aspect-ratio elliptic beams has been developed. In a small-aperture system image-charge effects have been found to be a new mechanism for inducing chaotic particle motion, …
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Spread spectrum satellite multiple access and overlay service
… of spread spectrum technology to very small aperture terminal (VSAT) satellite communication networks. It describes two spread spectrum multiple access systems which use a form of noncoherent M-ary FSK (MFSK) as the primary modulation and analyzes their throughput. The analysis …
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Performance analysis of VSAT networks
Very small aperture terminal (VSAT) networks offer a solution to the increasing demand for low-density voice and data communications. Spread Spectrum and single-channel-per-carrier (SCPC) transmission techniques work well for multiple access purposes while allowing the earth station antennas to …
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Global and Local Properties of Noninteracting Irregular Galaxies
… from intermediate band filter photometry, large aperture spectrophotometry, small aperture spectrophotometry of individual H II regions, and H I 21-cm observations. The gas and abundance parameters, combined with other derived quantities such as the SFR, the fraction of a galaxy involved in the …
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Design, fabrication, and characterization of high-speed light-emitting transistors and microcavity lasers
… vertical-cavity surface-emitting laser employing small aperture buried-oxide current and field confinement is also demonstrated with wider mode spacing and faster carrier recombination lifetime (enhanced Purcell factor ~ 2 to 8 times, but still limited cavity), lower threshold current, larger side …
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Overcoming the far-field diffraction limit via absorbance modulation
… close proximity or fabrication of a physically small aperture. Near-field apertures are dynamically generated in the photochromic absorbance modulation layer (AML) with only far-field illuminations. In this thesis, the concept of absorbance modulation is explained and in-house simulation models …
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Analysis and design of a data network for distance education for the state of Virginia
… bit error rate (BER) of 1E-6 or less. A very small aperture terminal (VSAT) network has also been proposed for the purpose.
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An educational VSAT system for Thailand
Very small aperture terminal (VSA T) networks offer great opportunities to combine satellite technology and the needs of education in Thailand. An educational VSAT network for Thailand needs a central hub station in Bangkok and seven remote sites with VSAT equipment. The network supports two way …
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Portable Tungsten Coil Atomic Emission and Atomic Fluorescence Spectrometry
… projector light bulb. The coil is housed in a small, aluminum cell. The emission signal exits from a small aperture in the cell, while the bulk of the blackbody emission from the tungsten coil is blocked. The resulting spectra exhibit extremely low background signals. The atomization cell, a …
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Design and characterization of flat lens antenna using aperture-coupled microstrip patches
… wave into planar wavefront at the back of the aperture. Therefore, the array unit cell must be designed to establish the required phase adjustment. Flat lens antenna elements which are based on aperture-coupled microstrip patches are presented. The lens contains 7×7 elements with a diameter of …
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Characterization of a piezoelectric transformer plasma source
… then generates an electric potential within the aperture of the PTPS. With an electrode pattern of a large annular electrode with a small aperture in the center the generated output voltage is larger than the applied voltage. Near the resonant frequency, the voltage step-up ratio can be very …
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The effects of heating and dehydration on the crystal structure of hemimorphite up to 600{u00B0}C
… may not qualify for a molecular sieve due to its small aperture size, it may be useful as an isotopic sieve.
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Performance analysis of star architecture packet-switched VSAT network using roll-call polling multiple access scheme
… This study analyses the performance of a Very Small Aperture Terminal (VSAT) satellite star network. The network uses roll-call polling as its multiple access scheme, High-level Data Link Control or HDLC, and go-back-N Automatic Repeat Request, for error control. The network is a VSAT …
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