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Articles 1 - 19 of 19
Full-Text Articles in Engineering
Analysis, Validation, And Improvement Of High-Resolution Wind Estimates From The Advanced Scatterometer (Ascat), Jeffrey Richard Blodgett
Analysis, Validation, And Improvement Of High-Resolution Wind Estimates From The Advanced Scatterometer (Ascat), Jeffrey Richard Blodgett
Theses and Dissertations
The standard L2B ocean wind product from the Advanced Scatterometer (ASCAT) is retrieved as a 25 km product on a 12.5 km grid. Ultra-high resolution (UHR) processing allows ASCAT wind retrieval on a high-resolution 1.25 km grid. Ideally, such a high-resolution sample grid provides wind information down to a 2.5 km scale, allowing better analysis of winds with high spatial variability such as those in near-coastal regions and storms. Though the wind field is sampled on a finer grid, the actual data resolution needs to be validated. This thesis provides an analysis and validation of ASCAT UHR wind estimates in …
B1 Mapping For Magnetic Resonance Imaging, Daniel Joseph Park
B1 Mapping For Magnetic Resonance Imaging, Daniel Joseph Park
Theses and Dissertations
Magnetic Resonance Imaging (MRI) is a non-ionizing form of medical imaging which has practical uses in diagnosing, characterizing, and studying diseases in vivo. Current clinical practice utilizes a highly trained radiologist to view MR images and qualitatively diagnose, characterize, or study a disease. There is no easy way to compare qualitative data. That is why developing quantitative measures in MRI show promise. Quantitative measures of disease can be compared across a population, MRI sites, and over time. Osteoarthritis is one disease where those who have it may benefit from the development of quantitative MRI measures. Those benefits may include earlier …
Compact Antennas And Arrays For Unmanned Air Systems, James Arthur Eck
Compact Antennas And Arrays For Unmanned Air Systems, James Arthur Eck
Theses and Dissertations
A simple and novel dual-CP printed antenna is modelled and measured. The patch antennais small and achieves a low axial ratio without quadrature feeding. The measured pattern showsaxial ratio pattern squinting over frequency. Possible methods of improving the individual element are discussed, as well as an array technique for improving the axial ratio bandwidth. Three endfire printed antenna structures are designed, analyzed, and compared. The comparison includes an analysis of costs of production for the antenna structures in addition to their performance parameters. This analysis concludes that cost of materials primarily reduces the size of antennas for a given gain …
Tincr: Integrating Custom Cad Tool Frameworks With The Xilinx Vivado Design Suite, Brad S. White
Tincr: Integrating Custom Cad Tool Frameworks With The Xilinx Vivado Design Suite, Brad S. White
Theses and Dissertations
The field programmable gate array (FPGA) is appealing as a computational platform because of its ability to be repurposed for a number of different applications and its relatively low design cost. Traditionally, FPGA vendors provide a set of electronic design automation (EDA) tools to assist customers with the implementation of their designs. These tools are necessarily general purpose, and the resulting tool flow does not provide the user much in the way of customization. Frameworks such as RapidSmith and Torc allow for the creation of custom CAD tools that are able to target actual Xilinx FPGA devices. However, they are …
Developments In Lfm-Cw Sar For Uav Operation, Craig Lee Stringham
Developments In Lfm-Cw Sar For Uav Operation, Craig Lee Stringham
Theses and Dissertations
Opportunities to use synthetic aperture radar (SAR) in scientific studies and military operations are expanding with the development of small SAR systems that can be operated on small unmanned air vehicles (UAV)s. While the nimble nature of small UAVs make them an attractive platform for many reasons, small UAVs are also more prone to deviate from a linear course due autopilot errors and external forces such as turbulence and wind. Thus, motion compensation and improved processing algorithms are required to properly focus the SAR images. The work of this dissertation overcomes some of the challenges and addresses some of the …
A Solid-State Ion Detector For Use In Portable Mass Spectrometry, Sadek Salman Sabbah
A Solid-State Ion Detector For Use In Portable Mass Spectrometry, Sadek Salman Sabbah
Theses and Dissertations
Mass spectrometry has long been used as a scientific tool in a wide variety of applications. A portable mass spectrometer would make many of these applications faster and more efficient. One of the key components of a mass spectrometer is its ion detection system; to make a mass spectrometer portable, this system must be small and involve as few components as possible. Single ion detection has been achieved through several methods, nearly all of which are well-known and understood. These methods, however, often require bulky vacuum and/or cooling systems in order to achieve high sensitivity. An ion detection system that …
Digital Back End Development And Interference Mitigation Methods For Radio Telescopes With Phased-Array Feeds, Richard Allen Black
Digital Back End Development And Interference Mitigation Methods For Radio Telescopes With Phased-Array Feeds, Richard Allen Black
Theses and Dissertations
The Brigham Young University (BYU) Radio Astronomy group, in collaboration with Cornell University, the University of Massachusetts, and the National Radio Astronomy Observatory (NRAO), have in recent years developed and deployed PAF systems that demonstrated the advantages of PAFs for astronomy. However, these systems lacked the necessary bandwidth and acquisition times to be scientifically viable. This thesis outlines the development of a 20-MHz bandwidth system that can acquire for much longer periods of time and across much larger bandwidths than previous BYU systems. A report of the deployment of this system on the 305-meter reflector at the Arecibo Observatory in …
Verifying Molecular Dynamics Using Dielectric Spectroscopy, Joshua Dee Smith
Verifying Molecular Dynamics Using Dielectric Spectroscopy, Joshua Dee Smith
Theses and Dissertations
The electrical properties of proteins in solution are important for their structure and function. Computational biophysics studies of proteins need accurate parameters to ensure that numerical simulations match physical reality. Past work in this eld has compared the electrical properties of proteins obtained from dielectric spectroscopy to numerical simulations of proteins in water with adjustment of pKa values to try to capture the inevitable changes in electrical conformation that will occur in a complex structure such as a folded protein. However, fundamental veri cation of the charge parameters of the amino acid building blocks in common molecular dynamics software packages …
Design And Analysis Of Receiver Systems In Satellite Communications And Uav Navigation Radar, Matthew Robertson Morin
Design And Analysis Of Receiver Systems In Satellite Communications And Uav Navigation Radar, Matthew Robertson Morin
Theses and Dissertations
The design of a low cost electronically steered array feed (ESAF) is implemented and tested. The ESAF demonstrated satellite tracking capabilities over four degrees. The system was compared to a commercial low-noise block downconverter (LNBF) and was able to receive the signal over a wider angle than the commercial system. Its signal-to-noise ratio (SNR) performance was poor, but a proof of concept for a low cost ESAF used for tracking is demonstrated. Two compact low profile dual circularly polarized (CP) reflector feed antenna designs are also analyzed. One of the designs is a passive antenna dipole array over an electromagnetic …
Recursive-Ransac: A Novel Algorithm For Tracking Multiple Targets In Clutter, Peter C. Niedfeldt
Recursive-Ransac: A Novel Algorithm For Tracking Multiple Targets In Clutter, Peter C. Niedfeldt
Theses and Dissertations
Multiple target tracking (MTT) is the process of identifying the number of targets present in a surveillance region and the state estimates, or track, of each target. MTT remains a challenging problem due to the NP-hard data association step, where unlabeled measurements are identified as either a measurement of an existing target, a new target, or a spurious measurement called clutter. Existing techniques suffer from at least one of the following drawbacks: divergence in clutter, underlying assumptions on the number of targets, high computational complexity, time-consuming implementation, poor performance at low detection rates, and/or poor track continuity. Our goal is …
Single Event Mitigation For Aurora Protocol Based Mgt Fpga Designs In Space Environments, Alexander Stanley Harding
Single Event Mitigation For Aurora Protocol Based Mgt Fpga Designs In Space Environments, Alexander Stanley Harding
Theses and Dissertations
This work has extended an existing Aurora protocol for high-speed serial I/O between FPGAs to provide greater fault recovery in the presence of high-energy radiation. To improve on the Aurora protocol, additional resets that affect larger portions of the system were used. Detection for additional error modes that occurred but were not detected by the Aurora protocol was designed. Radiation testing was performed on the Aurora protocol with the additional mitigation hardware. The test gathered large amounts of data on the various error modes of the Aurora protocol and how the additional mitigation circuitry affected the system. The test results …
Target Motion Estimation Techniques For Single-Channel Sar, Mark T. Crockett
Target Motion Estimation Techniques For Single-Channel Sar, Mark T. Crockett
Theses and Dissertations
Synthetic aperture radar (SAR) systems are versatile, high-resolution radar imagers useful for providing detailed intelligence, surveillance, and reconnaissance, especially when atmospheric conditions are non-ideal for optical imagers. However, moving targets in SAR images are smeared. Along-track interferometry is a commonly-used method for extracting the motion parameters of moving targets but requires a dual-aperture SAR system, which may be power- size- or cost-prohibitive. This thesis presents a method of estimating target motion parameters in single-channel SAR data given geometric target motion constraints. I test this method on both simulated and actual SAR data. This estimation method includes an initial estimate, computation …
Signal-To-Noise Measurements And Particle Focusing In Liquid-Core Waveguides, Michael A. Olson
Signal-To-Noise Measurements And Particle Focusing In Liquid-Core Waveguides, Michael A. Olson
Theses and Dissertations
This thesis presents an analysis of the signal-to-noise ratio in liquid core anti-resonant reflecting optical waveguides (ARROWs) and the application of hydrodynamic focusing to the waveguides. These concepts are presented as a method to improve the detection capabilities of the ARROW platform. The improvements are specifically targeted at achieving single molecule detection (SMD) with the devices. To analyze the SNR of the waveguides a test platform was designed and fabricated. This test platform was then used to examine relationship between the SNR and the location of the excitation region. It was determined that the excitation region should be moved closer …
Power Side-Channel Dac Implementations For Xilinx Fpgas, Daniel Chase Savory
Power Side-Channel Dac Implementations For Xilinx Fpgas, Daniel Chase Savory
Theses and Dissertations
This thesis presents a novel power side-channel DAC (PS-DAC) which is constructed from user-controllable short circuits in FPGAs and which manipulate overall system power through dynamic power dissipation. Alternately, similar PS-DACs are created using shift-register primitives(SRL16E) which manipulate system power through switching logic, for means of comparison with short-circuit-based PS-DACs. PS-DACs are created of various sizes using both short-circuit-based and shift-register-based methods. These PS-DACs are characterized in terms of output linearity,monotonicity, and frequency distortion. Applications explored in this thesis which use PS-DAC technology include a Simple Power Analysis (SPA) side-channel transmitter, and a frequency watermarking application. These applications serve as …
Application Improvements Of Slab-Coupled Optical Fiber Sensors, Spencer L. Chadderdon
Application Improvements Of Slab-Coupled Optical Fiber Sensors, Spencer L. Chadderdon
Theses and Dissertations
This dissertation explores techniques for improving slab-coupled optical fiber sensor (SCOS) technology for use in specific applications and sensing configurations. SCOS are advantageous for their small size and all-dielectric composition which permit non-intrusive measurement of electric fields within compact environments; however, their small size also limits their sensitivity. This work performs a thorough analysis of the factors contributing to the performance of SCOS and demonstrates methods which improve SCOS, while maintaining its small dimensions and high level of directional sensitivity. These improvements include increasing the sensitivity by 9x, improving the frequency response to include sub 300 kHz frequencies, and developing …
Passive And Electronically Steered Array Planar Feeds For Satellite Communications, Kyle C. Browning
Passive And Electronically Steered Array Planar Feeds For Satellite Communications, Kyle C. Browning
Theses and Dissertations
As the need for more bandwidth increases, satellite communication (SatCom) terminals are forced to climb higher in frequency. Higher frequency means greater propagation losses, and so antenna gain and sensitivity have to increase. The higher the gain, the more difficult it is to point the antenna. To make matters even more challenging, consumers are requesting satellite links in harsher environments and on moving vehicle and planes. In order to meet today's challenges and improve on dish feeds, research is ongoing to replace fixed-beam feedhorns with smaller, cheaper, and lighter PCB based antennas and to develop low-cost electronically steered array feeds …
Modulation And Synchronization For Aeronautical Telemetry, Christopher G. Shaw
Modulation And Synchronization For Aeronautical Telemetry, Christopher G. Shaw
Theses and Dissertations
Aeronautical telemetry systems have historically been implemented with constant envelope modulations like CPM. Shifts in system constraints including reduced available bandwidth and increased throughput demands have caused many in the field to reevaluate traditional methods and design practices. This work examines the costs and benefits of using APSK for aeronautical telemetry instead of CPM. Variable rate turbo codes are used to improve the power efficiency of 16- and 32-APSK. Spectral regrowth in nonlinear power amplifiers when driven by non-constant envelope modulation is also considered. Simulation results show the improved spectral efficiency of this modulation scheme over those currently defined in …
Compact Fmcw Radar For Gps-Denied Navigation And Sense And Avoid, James David Mackie
Compact Fmcw Radar For Gps-Denied Navigation And Sense And Avoid, James David Mackie
Theses and Dissertations
Location information is vital for any type of aircraft and even more crucial for Unmanned Aerial Systems (UAS). GPS is a readily available solution but signals can easily be jammed or lost. In this thesis, radar is explored as a backup system for self-localization when GPS signals are not available. The method proposed requires that an area be pre mapped by collecting radar data with known latitude and longitude coordinates. New radar data is then collected and compared to previously stored values. Channel matrices are stored at each point and are used as the basis for location comparisons. Various methods …
High-Resolution Mri For 3d Biomechanical Modeling: Signal Optimization Through Rf Coil Design And Mr Relaxometry, James A. Badal
High-Resolution Mri For 3d Biomechanical Modeling: Signal Optimization Through Rf Coil Design And Mr Relaxometry, James A. Badal
Theses and Dissertations
Computed Tomography (CT) is often used for building 3D biomechanical models of human anatomy. This method exposes the subject to a significant x-ray dose and provides limited soft-tissue contrast. Magnetic Resonance Imaging (MRI) is a potential alternative to CT for this application, as MRI offers significantly better soft-tissue contrast and does not expose the subject to ionizing radiation. However, MRI requires long scan times to achieve 3D images at sufficient resolution, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR). These long scan times can make subject motion a problem. This thesis describes my work to reduce scan time while achieving sufficient …