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Full-Text Articles in Engineering
Performance Prediction Of Quantization Based Automatic Target Recognition Algorithms, Matthew Steven Horvath
Performance Prediction Of Quantization Based Automatic Target Recognition Algorithms, Matthew Steven Horvath
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The difficulty of designing automatic target recognition (ATR) systems is that there are many sources of potential variation in the data, often referred to as operating conditions (OCs). Typical evaluation methodologies rely on empirical simulations on fixed datasets, where it can be difficult to fully sample the variations the algorithm will see in application. Here we focus on analytic performance prediction approaches to quantization based algorithms where the sources of variation are assumed conditionally independent. We have focused on three algorithms in particular: multinomial pattern matching (MPM), quantized grayscale matching (QGM), and a quantized mean-squared error approach (QMSE). The first …
Nano-Materials For Microwave And Terahertz Applications, Joshua Myers
Nano-Materials For Microwave And Terahertz Applications, Joshua Myers
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In this age of digital electronics the quest for faster computational devices and high speed communications have driven a need for new materials that are capable of fulfilling these goals. In both areas the need for a thinner channel in transistors, faster carrier transport characteristics, and better magnetic materials dominate the direction of research. Recently 2D materials have been realized. These single layer atomic thick materials show potential in having extremely high carrier transport velocities at room temperature and, due to their natural 2D structure, are the thinnest material possible in nature. On the other hand spin-spray ferrites have showed …
A Framework For Uncertainty Quantification In Microstructural Characterization With Application To Additive Manufacturing Of Ti-6al-4v, Gregory Thomas Loughnane
A Framework For Uncertainty Quantification In Microstructural Characterization With Application To Additive Manufacturing Of Ti-6al-4v, Gregory Thomas Loughnane
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The sampling of three dimensional (3D) mesoscale microstructural data is typically prescribed using simple rules, likely resulting in data under- or oversampling depending on the measurement(s) of interest. The first part of this work investigates one approach for determining a minimally sufficient sampling scheme for 3D microstructural data, using computer-generated phantoms of polycrystalline grain microstructures. Sources of error that are observed experimentally are modeled using phantoms, in order to determine the effect that errors have on the microstructural statistic(s)-of-interest. Minimally-sufficient sampling schemes are then established based on a required accuracy in the microstructural statistic(s). The characterization error modeling framework is …
Large Scene Sar Image Formation, Leroy A. Gorham
Large Scene Sar Image Formation, Leroy A. Gorham
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With new advances in digital signal processing technology, Synthetic Aperture Radar (SAR) systems are capable of collecting high resolution data over very large scenes. Well known image formation algorithms such as the polar format algorithm (PFA) create image artifacts in large images due to phase errors introduced by the algorithm. In this dissertation, we analyze the nature of these artifacts by comparing PFA to an exact imaging algorithm, the backprojection algorithm (BPA). First, we perform a novel phase error analysis by decomposing the PFA phase errors into constant, linear, and quadratic terms for arbitrary flight paths. Second, we utilize the …
Modern Digital Chirp Receiver: Theory, Design And System Integration, Stephen Ray Benson
Modern Digital Chirp Receiver: Theory, Design And System Integration, Stephen Ray Benson
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Chirp signals can achieve a high range resolution without sacrificing SNR or maximum range, making them a strong candidate for use in radar and sonar applications. Chirp signals are also power efficient and resistant to interference, making them well suited for communication applications as well. The proposed digital high chirp rate receivers will showcase the use of digital instantaneous frequency measurement (IFM) devices for high chirp rate measurement. The receivers are paired with a high resolution time-of-arrival algorithm, capable of detecting the TOA and TOD of a pulse with an average error of less than 2ns. The high resolution pulse …
The Effects Of Proximity Compatibility And Graphics On Spatio-Temporal Situation Awareness For Navigation, Chang-Geun Oh
The Effects Of Proximity Compatibility And Graphics On Spatio-Temporal Situation Awareness For Navigation, Chang-Geun Oh
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While aircraft pilots must attain awareness of both pertinent spatial and temporal navigation information in the Next Generation Air Transportation System, current flight decks present spatial and temporal information separately. This research explored display design to enhance situation awareness (SA) while conducting navigation with spatial and temporal constraints (space-time navigation). For Experiment 1, static maps were developed for space-time navigation including scheduled/estimated time of arrival for passengers at bus stops on public bus routes. The maps varied time status representation and format of indicated time into four conditions. To examine SA, the test program provided 23 non-pilot participants with the …