With the rapid development of wireless communication technology, the demands for higher communication rates are increasing. Higher communication rate corresponds to higher DoF. Interference alignment, which is an emerging interference management technique, is able to substantially increase the DoF of wireless communication systems. This thesis mainly studies the delay-based interference alignment technique. The key problem lies in the design of the transmission scheme and the appropriate allocation of the propagation delay, so as to achieve the desired DoF of different wireless networks. In addition, through delay-based interference alignment, the achievability of extreme points of the DoF region of different wireless networks can be proved.

We developed an extreme ultraviolet (EUV) polarimeter, which employs laser-generated high-order harmonics as the light source. This relatively high-flux directional EUV source has available wavelengths between 8 nm and 62 nm and easily rotatable linear polarization. The polarimeter will aid researchers at BYU in characterizing EUV thin films and improving their understanding of materials for use in EUV optics. This first-time workhorse application of laser high harmonics enables polarization-sensitive reflection measurements not previously available in the EUV. We have constructed a versatile positioning system that places harmonics on the microchannel plate detector with an accuracy of 0.3 mm, which allows a spectral resolution of about 180. We have demonstrated that reflectance as low as 0.2% can be measured at EUV wavelengths and that this data is repeatable to within the error of our source stability (~7% fluctuation). We have compared reflectance data with that taken from the same sample at Beamline 6.3.2 at the Advanced Light Source. This data agrees well from 5 degrees to 30 degrees and the angular locations of the interference fringes also agree.

Classical models for multivariate or spatial extremes are mainly based upon the asymptotically justified max-stable or generalized Pareto processes. These models are suitable when asymptotic dependence is present. However, recent environmental data applications suggest that asymptotic independence is equally important. Therefore, development of flexible subasymptotic models is in pressing need. This dissertation consists of four major contributions to subasymptotic modeling of multivariate and spatial extremes. Firstly, the dissertation proposes a new spatial copula model for extremes based on the multivariate generalized hyperbolic distribution. The extremal dependence of this distribution is revisited and a corrected theoretical description is provided. Secondly, the dissertation thoroughly investigates the extremal dependence of stochastic processes driven by exponential-tailed Lévy noise. It shows that the discrete approximation models, which are linear transformations of a random vector with independent components, bridge asymptotic independence and asymptotic dependence in a novel way, whilst the exact stochastic processes exhibit only asymptotic independence. Thirdly, the dissertation explores two different notions of optimal prediction for extremes, and compares the classical linear kriging predictor and the conditional mean predictor for certain non-Gaussian models. Finally, the dissertation proposes a multivariate skew-elliptical link model for correlated highly-imbalanced (extreme) binary responses, and shows that the regression coefficients have a closed-form unified skew-elliptical posterior with an elliptical prior.

Coral reefs are threatened due to anthropogenic stressors, especially due to warming. Corals typically live in a narrow range of environmental conditions; however, some individuals are able to thrive in extreme temperatures. Such colonies could provide insight into how the coral holobiont acclimates or adapts to extreme temperatures. This study used the model coral species Stylophora pistillata (Esper, 1797) in the Saudi Arabian Red Sea, which is abundant and occurs across a range of desired microhabitats to examine the role of the environment on population structure and physiology. Specifically, this project aimed to 1) review the literature on S. pistillata used in stress studies to better understand the threats it faces, and where knowledge gaps exist, 2) conduct a demographic assessment of S. pistillata populations across different reefs and microhabitats, and 3) evaluate the physiological state of S. pistillata colonies occurring in these microhabitats with differing temperature profiles. The literature review revealed disparities in stress studies on S. pistillata, with most originating from the Gulf of Aqaba and conducted on temperature tolerance. The population assessment showed a high spatial variability in size structure, but a tendency for offshore reefs to have larger colonies and higher colony density. It also showed that purple color morphs tended to be more frequently encountered in the exposed reef flat zones. Similarly, the physiological study showed high spatial variability in chlorophyll, protein and lipid content, and skeletal and symbiont density. However, there was a clear seasonal component, with a multivariate analysis revealing the coolest sampling period as distinct. The metabolic profiles of S. pistillata indicated that offshore colonies differ from midshelf and nearshore colonies. Finally, an opportunistic study reports a case of S. pistillata bleaching due to an unusual occurrence of cold stress coupled with a low tide, supporting the notion that continued monitoring of this population on the reef flat is important for documenting rare evets and understanding their impacts on coral ecology. Taken together, this thesis establishes baseline information on the ecology of an important Red Sea coral inhabiting an extreme environment, and will be important for understanding its response to future changes.

Groundnut production is vital to the Senegalese agricultural economy, particularly in the Groundnut Basin. However the region is increasingly affected by climate change and associated rising temperatures. This study investigates long-term changes in the frequency of extreme temperatures in the Groundnut Basin and the impact of extreme temperatures on groundnut production. The current economic costs of extreme temperatures on groundnut farmers and potential future additional economic costs associated with climate change are then calculated. The study uses a two-year panel dataset from 1,123 households in the Groundnut Basin and weather data from meteorological stations and the ERA5 climate database. Results identify a significant increasing trend in extreme temperatures across the Groundnut Basin and a negative relationship between extreme temperatures and groundnut yield. This leads to financial losses for farmers, with adaptation strategies such as input level adjustments providing partial mitigation. Future projections indicate further increases in extreme heat degrees days, resulting in significant yield losses by 2050. But the implications of extreme heat also extend beyond agriculture, affecting human habitation and exacerbating societal inequalities. The findings highlight the potential long-term effects of increasing temperatures on agricultural practices in the Groundnut Basin and underscore the need for adaptation and mitigation strategies to cope with the impacts of climate change. / Master of Science / Groundnut production plays an important role in Senegal's agricultural economy, particularly in the Groundnut Basin. However, the region is facing growing challenges due to climate change and rising temperatures. This study examines the long-term changes in extreme temperatures in the Groundnut Basin and their impact on groundnut production. By analyzing data from 1,123 households and temperature records, the study calculates the current economic costs of extreme temperatures on groundnut farmers and predicts potential future costs associated with climate change. The findings reveal a significant increase in extreme temperatures across the Groundnut Basin, which has a negative effect on groundnut yields. As a result, farmers face financial losses. However, they are employing adaptation strategies, such as adjusting input levels, to partially mitigate these losses. In the future, projections indicate that extreme heat will continue to rise, leading to substantial yield losses by 2050. But the implications of these findings also go beyond agriculture, impacting human settlements and exacerbating existing societal inequalities. The study emphasizes the potential long-term consequences of increasing temperatures on groundnut farming in the Groundnut Basin and highlights the urgency of implementing adaptation and mitigation strategies to address the impacts of climate change.

This thesis is a novella highlighting the struggle many religious individuals face to maintain a faith with or without physical props and boundaries, and why some people voluntarily live with pharisaical rules that make it harder to reside in the modern world. Maid for Man is the story of Caty, a young woman brought up by the strict conservatism of a combined church and homeschool group, who, after marrying a man and discovering he has no physical interest in her, must decide whether or not to divorce him, even though her family and community believe divorce is an excommunicable sin.

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