LOUIS University of Alabama in Huntsville
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Development of a Racetrack Magnetic Nozzle for Use in Pulsed Fusion Propulsion of Spacecraft
No full texthttps://louis.uah.edu/rceu-hcr/1512/thumbnail.jp
Doppler Radar Observations of Near-Surface Wind Profiles During the Landfall of Hurricane Laura (2020)
No full texthttps://louis.uah.edu/rceu-hcr/1521/thumbnail.jp
Analyzing Kepler Light-Curves of Eclipsing Binary Stars
No full texthttps://louis.uah.edu/rceu-hcr/1524/thumbnail.jp
Unbound subgenres : overlapping age categories in contemporary romance and their implications
No full textThis thesis aims to highlight the importance of genre labelling in contemporary romance fiction and the larger implications that come from the misuse of labels. Considerations of the genre based on narrative elements (Regis, 2003; Michelson, 2022), age categorization (Cart, 2011; Tribunella, 2007), and emerging market conditions (McAlister, 2018; Stewart, 2013) have generated considerable discussion over the last twenty-five years. While each of these scholars draws important conclusions about romance and its subgenres, none of them consider the significance of reader opinion, which is now enhanced due to literary digital spaces. In this paper, I examine nine romance novels for their narrative elements and sexual content before considering the ways in which the marketing of these texts differs between publishers, authors, and their respective readers. The results show varied understanding of each subgenre’s meaning, for which I suggest the implementation of a new maturity rating system
Near-field analysis of horn antennas for electromagnetic compatibility testing
No full textStandard gain horn antennas are widely used in electromagnetic compatibility (EMC) testing and antenna measurements. In EMC testing, it is often required to generate high electric field intensities across a wide frequency range within the near-field region. However, the focusing properties of antennas are deteriorated in the radiating near-field region. In order to increase engineering confidence in EMC testing, it is desirable to understand the root causes of the aforementioned radiation degradation. In this thesis, the near-field characteristics of three different pyramidal standard gain horns are investigated using full-wave analysis, analytical methods, and measurement. The causes of near-field gain reduction are examined, as well as the accuracy of a commonly used analytical gain approximation for different horns. The main goal is to develop a process to estimate the near-field gain of horn antennas through various methods as well as foster deeper insight into the near-field behavior of horn antennas
Blockchain poisoning attacks in federated learning
No full textFederated Learning (FL) enables collaborative model training across distributed clients without sharing raw data, thereby preserving privacy. However, conventional FL depends on a centralized aggregator, exposing it to poisoning and backdoor attacks that threaten model integrity. This thesis introduces B-ZkFed, a blockchain-based and zero-knowledge proof (ZKP)-enhanced FL framework designed to ensure verifiable trust, transparency, and robustness. The blockchain layer decentralizes aggregation through smart contracts, while the ZKP module allows clients to cryptographically prove the correctness of updates without revealing private data. A multi-layer adaptive defense combining gradient-norm filtering, model-similarity analysis, and robust aggregation mitigates poisoning threats under both IID and Non-IID settings. Experiments on the CIFAR-10 dataset show that B-ZkFed reduces attack success rates by up to 30.7% and sustains accuracy within 3-4% of the clean baseline, with minimal computational overhead. Overall, B-ZkFed establishes a verifiable, privacy-preserving, and tamper-resistant foundation for secure federated intelligence
Utilizing ground-based radar analyses to investigate ocean-to-land differences in the tropical cyclone wind profile and their impacts on tornadogenesis
No full textOn 20 August 2008, the MAX radar was deployed southeast of the Jacksonville, FL WSR-88D radar to monitor the boundary layer before, during, and after the landfall of TS Fay. During the 57-hour deployment, MAX sampled around a tornadic rainband that produced at least one confirmed tornado. To illustrate TCBL changes across a coastal zone, VAD profiles from MAX and KJAX are compared, and a dual- Doppler analysis is performed. One key finding from the DDA was the consistent presence of southeasterly background flow, vertical vorticity, enhanced cyclonic shear zones, and minisupercells throughout the 1650-1725 UTC analysis period. The primary rainband separated stronger southeasterly flow (to the east) from weaker southeasterly flow (to the west). One key finding from the VAD was that the wind profile differences were greatest below 500 m AGL. SRH10−1000m was 35% greater at KJAX than at MAX due to longer hodographs produced by weaker low-level flow
Air-breathing hypersonic missile control using adaptive higher order sliding mode control driven by finite- and fixed-time sliding mode observers
No full textThis research is focused on the study of the trajectory tracking of a Hypersonic Missile (HM) in its terminal phase of flight in light of the cross coupling, high nonlinearity, and uncertainty in the missile dynamics. This is coupled with unmatched disturbances and perturbations that all need to be compensated for in a really short time. In this research, a relative degree approach is utilized to design an adaptive higher order sliding mode control (AHOSM) for controlling the nonlinear perturbed HM. This technique allows for the proposed observation/differentiation/control (autopilot) algorithms equipped with adaptation capabilities to be employed for designing the HM integrated guidance and autopilot. This research develops each portion of the proposed algorithm and the corresponding differentiator settling time estimation. The HOSM observer exactly estimates the perturbations which is used by the controller to cancel out the nonlinear perturbations. An adaptive nonlinear continuous finite time convergent control algorithm is used in conjunction with HOSM differentiators to control the system response to track the desired terminal phase trajectory. The double-layer adaptive algorithm is based on equivalent control concept and does not allow overestimation of the control gains which mitigates control chattering and yields control continuity. Fixed convergence time estimation is achieved independent of initial conditions of the differentiation errors. The robustness and high accuracy output tracking in the presence of matched and unmatched external disturbances and missile model uncertainties is demonstrated for both the differentiator and controller via Monte Carlo simulations
Effects of Band-K reordering on sparse tensor formats for parallel architectures
No full textThis thesis presents a background in sparse tensor formats and a study of the effects of Band-K and lexi-ordering on the HiCOO sparse tensor format using the matricized tensor times Khatri-Rao product (MTTKRP). We provide a background of sparse tensors and tensors in general. We cover several foundational sparse tensor formats including CSR, BCSR, and COO, and extensions to those formats HiCOO and CSR-K. Furthermore, we discuss methods of reordering tensors using Band-K and lexi-ordering. Finally, we modify HiParTI to supporting Band-K reordering over slices and benchmark the results against lexi-ordering and natural ordering
