Physical Sciences and Mathematics Commons^™

Comparison Of Nutrient Concentrations And Primary Production Indicators Across Plume Fronts, Taylor Dishon

Electronic Theses and Dissertations

Coastal buoyant plumes carry low-salinity waters containing particulate and dissolved terrestrial materials with an abundance of nutrients into the coastal ocean, including inorganic nitrogen and phosphorous. Plume fronts act as transport barriers created from the convergence of a fresher plume with an older, saltier plume or with ambient waters, leading to potential accumulation of phytoplankton and nutrients. This accumulation creates an optimal environment for primary production. The primary goals of this study were: to investigate the distribution of and potential relationships between nutrient concentrations and chlorophyll a across plume fronts of the Winyah Bay River Plume, and examine potential relationships …

Performance Of The Two Sample Likelihood Ratio Test Under A Nested Dirichlet: A Simulation Study, Edwina Agyeman

Electronic Theses and Dissertations

Compositional data analysis (CoDA) addresses multivariate data constrained to a constant sum, such as proportions or percentages. Originating from early warnings regarding misinterpretation by Pearson (1897), the field was formalized by John Aitchison in 1986, whose foundational work remains highly influential. Over time, new modeling techniques and visualization tools have advanced the field, as noted by Greenacre et al. More recently, Turner et al. proposed an approach based on the Nested Dirichlet Distribution (NDD), which accommodates more flexible dependence structures than the standard Dirichlet model. This thesis builds on the methodology of Turner et al. Chapter 1 introduces the nature …

Evaluating Alpha Spending Functions Applied To Observational Time-To-Event Analysis, Moses Torgbenu

Electronic Theses and Dissertations

This thesis explores the theoretical foundation of the alpha spending approach and extends its application beyond the conventional setting of randomized controlled trials (RCTs) to observational studies with time to event analyses. In these less structured environments, key design parameters such as the total number of events are often unknown, posing challenges for the standard implementation of sequential analysis methods.

Through simulation studies, this research delivers several important contributions. First, it presents a modified approach that uses calendar time to define the timing of interim analyses while relying on event-based information to estimate the correlation among test statistics. This adjustment …

Simultaneous Application Of Multiple Process Control Rules, Tran B. Ngo

Electronic Theses and Dissertations

Statistical Process Control (SPC) charts are tools used in quality control to monitor and analyze the stability of a process over time. This study evaluates the effectiveness of eight individual Western Electric rules, also known as WECO rules, and the various combinations of these rules with Shewhart rule (or WECO rule 1) to SPC charts. As more rules are added to a process control scheme with Rule 1, there is a trade-off: a higher false out-of-control signal rate but an increase in sensitivity, that is the ability of a specified process control scheme to capture a true out-of-control signal. This …

Mixture Effects On Metal Accumulation In The Asian Clam, Corbicula Fluminea, Mark A. Huff

Electronic Theses and Dissertations

Field collected Corbicula fluminea were exposed to trace level copper, lead, and zinc with the aim of examining the preferential accumulation between the soft tissue and shell. Metal levels were based on those in a permitted industrial effluent. At 1X effluent and 2X effluent exposure levels, copper was found to preferentially accumulate in the clam soft tissue, lead was found to preferentially accumulate in the clam shell, and zinc was found to excrete back into the diluent after preferentially accumulating in the clam soft tissue. When exposed as a mixture at 1X effluent levels, copper and lead were found to …

Diagenesis And Controls On Porosity And Permeability In The Upper San Andres Formation Of West Texas, Jack Butcher

Electronic Theses and Dissertations

West Texas reservoirs on the Central Basin Platform (CBP) are dominated by Permian-age carbonate deposits, significantly contributing to petroleum production. The Upper Permian-aged San Andres Formation, composed primarily of dolomite and limestone, is a prolific reservoir. This study assesses diagenetic influences on porosity and permeability within the San Andres Formation along the northern CBP. Two cores from the Monument 4-2 and Peterson 1 wells in West Texas were analyzed using core descriptions, thin section petrography, XRD, XRF, and MICP. Results indicate that dolomitization enhances porosity, with intercrystalline and moldic porosity being dominant, while late-stage cementation and compaction reduce permeability. XRD …

Estimation Methods For Bayesian Exponential Random Graph Models Under The Horseshoe Prior., Pamela Linares

Electronic Theses and Dissertations

Networks are powerful tools for modeling the complexity of social interactions, biological systems, and information spread. A leading statistical frameworks for analyzing network data are Exponential Random Graph Models (ERGMs), which provide a principled approach to capturing structural dependencies. However, ERGMs remain challenging to estimate, especially in sparse or high-dimensional settings where models suffer from degeneracy and unstable parameter inference. This paper proposes a penalized Bayesian approach to ERGMs that utilizes the horseshoe prior, a sparsity-inducing global-local shrinkage prior. This prior offers robust regularization while preserving important signals, improving estimation by shrinking irrelevant parameters and reducing the impact of extreme …

Recent Studies On The Reactions And Synthesis Of Nitrogen And Sulfur - Containing Heterocyclic Pharmacophores., Bernard Louis Adjei

Electronic Theses and Dissertations

Nitrogen and sulfur-containing heterocycles remain significant classes of compounds in the field of medicinal and organic chemistry due to their unique structural features and diverse biological activities which make them of considerable interest for drug discovery and development. Notable examples of the nitrogen containing heterocycles include the phthalimide and glutarimide rings present in thalidomide. Thalidomide, a potent small-molecule therapeutic agent, precipitated a significant global drug crisis due to its teratogenicity, causing congenital malformations in phocomelia infants, which remains unrivaled over half a century ago. Currently, thalidomide derivatives are extensively utilized in the therapeutic management of various hematological malignancies. Recent investigations …

Evometric: An Interactive Framework For Scalable Visual Analytics Of Time Series Data With Dynamic Changes., Jiahang Huang

Electronic Theses and Dissertations

In today's data-intensive landscape, rapid advances in digital sensing and recording technologies have enabled the acquisition of high-resolution multimodal time series data, capturing intricate real-world dynamics across various domains such as healthcare, behavioral science, and environmental monitoring. However, the complexity and scale of these datasets present significant analytical challenges, particularly in understanding dynamic changes at both individual and cohort levels. This dissertation introduces EvoMetric, a novel visual analytics framework designed to support scalable exploration and analysis of large-scale multimodal time series data with dynamic changes. EvoMetric seamlessly integrates individual-level temporal dynamics with population-level comparative insights, enabling users to visually …

Synthetic And Pharmacological Diversity Of Nitrogen-Containing Heterocycles., Shramana Ghosh

Electronic Theses and Dissertations

Nitrogen-containing heterocycles are a foundational class of compounds in organic chemistry, playing critical roles in pharmaceuticals, agrochemicals, and natural products due to their structural diversity and biological relevance. Among them, isoindolinones are notable for their wide range of pharmacological activities. Structurally, isoindolinones possess a benzylic methylene group adjacent to the nitrogen atom, which allows for selective oxidative transformations to yield phthalimide derivatives, well-known intermediates in synthetic, pharmaceutical, and materials chemistry. Although phthalimide is traditionally employed as a protecting group for amines via the Gabriel synthesis, isoindolinone offers a valuable alternative. Through a modified Gabriel-like approach, isoindolinones can serve as more …

Electrochemical And Electrocatalytic Properties Of Screen-Printable Carbon Inks Featuring Pyridinic Nitrogen-Containing Polymeric Binder, Albert Sam Junior

Electronic Theses and Dissertations

Screen-printable conductive inks have been widely applied to prepare electrodes for electrochemical sensing. These inks generally consist of conductive metal or carbon particles, solvents, and polymeric binders. Low-cost, carbon-based, screen-printable conductive inks are especially popular. However, screen-printed carbon electrodes (SPCEs) must often be modified after they are printed to impart the necessary characteristics (e.g., sensitivity, selectivity, stability) for the desired application. For example, nitrogen-doping of SPCEs, especially in ways that introduce pyridinic or pyrrolic nitrogen species, can impart electrocatalytic properties towards reduction of O₂, H₂O₂, and CO₂. While our previous work done …

Confidence Intervals For The Difference And Ratio Of Two Means From Independent Beta Distribution, Albert Ashong

Electronic Theses and Dissertations

This thesis explores constructing and evaluating confidence intervals for the difference and ratio of means from two independent Beta distributions using Maximum Likelihood Estimation (MLE) and the Wald method. It addresses the limitations of traditional methods due to the unique properties of Beta distributions. Extensive simulation studies assess interval performance based on coverage probability and Average width. The study aims to provide robust tools for statistical analysis in fields where Beta distributions are common, enhancing understanding and application of these methods in various scientific domains. Additionally, these confidence intervals will be applied to real biological data from a Morris Water …

Multi-Label Classification Of Acoustic And Electronic Drum Sounds Using Machine Learning, Sean Perman

Electronic Theses and Dissertations

This paper presents a system for multi-class classification of drum sounds using audio signal processing and machine learning techniques. The project utilizes a diverse dataset of both acoustic and electronic drum samples and extracts ten distinct audio features to capture the timbral and temporal characteristics of each sound. The methodology includes signal preprocessing, feature extraction, and the application of supervised classification algorithms to distinguish between multiple drum classes. Experimental evaluations demonstrate that the selected features significantly enhance classification accuracy across a varied dataset. These findings underscore the effectiveness of combining traditional audio processing with modern machine learning, offering promising applications …

Enhancing Multi-Step Stock Price Forecasting With Social Media Sentiment And Engagement Metrics, Damilare Olaniyan

Electronic Theses and Dissertations

This thesis investigates whether social media sentiment can improve the accuracy of stock price prediction beyond traditional historical data. While financial markets have long relied on structured numerical indicators, the growing influence of public discourse on platforms like Twitter has introduced new opportunities for extracting market-relevant signals from unstructured text. The study focuses on four major technology firms and combines sentiment features derived from Twitter with historical stock prices in a hybrid machine learning framework. Engagement-weighted sentiment, linguistic complexity, and polarity intensity were extracted using natural language processing techniques and incorporated into classification and regression models. Results show that including …

Collaborative Federated Learning For Robots In Heterogeneous Environments, Karlan Schneider

Electronic Theses and Dissertations

This research investigates the performance of Federated Averaging (FedAvg) in simulated Federated Learning (FL) scenarios with varying degrees of environmental heterogeneity among robotic agents. The study explores the impact of data heterogeneity on both the convergence of FedAvg and the fairness of learning, with regard to consistency of performance across agents. Experiments were conducted with simulated robots trained to perform a target collection task, where a subset of agents encountered an unfamiliar environment. The results demonstrate that while FedAvg exhibits resilience to the introduction of new environmental data, it struggles to ensure both convergence and fairness in heterogeneous settings. Specifically, …

Photochemistry Of Quinones And Combustion-Derived Particles, Desiree J. Sarmiento

Electronic Theses and Dissertations

Quinones are ubiquitous species that can be produced from the photochemical aging of combustion-derived particles (CDPs). Polycyclic aromatic hydrocarbons (PAHs) are a major component of CDPs and are precursors to quinones and other oxidized products (OPAHs). My work first expanded on the PAH and OPAH photochemistry research of Dr. John Haynes, who showed that anthracene (ANT) oxidizes into 1,4-naphthoquinone (1,4-NAPQ), 1,4-anthraquinone (1,4-ANTQ), and 9,10-anthraquinone (9,10-ANTQ), and of Dr. Heather Runberg, who demonstrated the ability of ANT and these quinones to generate reactive oxygen species (ROS). Then at the Pacific Northwest National Laboratory (PNNL), I was given the opportunity to investigate …

Optimizing Option Market Clearing, Juan Andrés Malaver Alvarado

Electronic Theses and Dissertations

Modern options markets clear each strike in isolation, leaving cross-strike arbitrage unexploited. This thesis applies a payoff-dominant clearing mechanism to realized trades—roughly 2 000 Cboe VIX option executions from June–November 2016—after classifying each trade’s side and bundling by expiration. Three optimization formulations are tested: a fractional linear program (LP), a mixed-integer LP, and a pure integer program. On a 10-core laptop every bundle solves in < 0.5 s. The LP captures the greatest surplus, yet the integer models recover nearly as much while filling whole contracts and holding only modest margin. Results reveal persistent, albeit small, inefficiencies in executed trades and demonstrate that an integral cross-strike auction could operate in real time. The accompanying C/Gurobi code is modular and readily extendable to early-exercise options. Trade-level evidence thus supports redesigning exchange clearing to consider the complete option book.

Culture And Environment: The Calling Lakes Ecomuseum As A Community Sustainability Initiative, Kace N. Anders

Electronic Theses and Dissertations

Located in Saskatchewan, Canada, the Calling Lakes Ecomuseum, CLEM, is a community-based organization focused on water management and sustainability. Ecomuseums are holistic organizations that occupy landscapes, are responsive to community needs, conserve in situ heritage, and incorporate sustainability along with community development. The ecomuseum movement came from a need for holistic heritage management that disengaged with conventional museology and created space for communities to engage with their heritage in ways that promote community identity. This thesis analyzes the Calling Lakes Ecomuseum and how it utilizes the ecomuseum concept alongside environmental sustainability. Both semi-structured interviews and place-based field observations were used …

Conceptualizing The Explanatory Fully Longitudinal Mixed Methods Case Study Design: A Demonstration With An Arithmetic Education Trial With Kindergarten Children, Menglong Cong

Electronic Theses and Dissertations

In employing longitudinal mixed methods designs, researchers have commonly used the fully longitudinal mixed methods design. This has occurred mostly in the health sciences but less in education. The current investigation proposes a novel longitudinal mixed methods research design, explanatory fully longitudinal mixed methods case study design. It demonstrates its potential for addressing research inquiries in educational research using the arithmetic learning trajectories datasets. This study is presented in three components. The first is a quantitative phase, selecting an exploratory case from a previous arithmetic learning trajectories study (Clements et al., 2021) for qualitative analyses based on maximizing the …

Some Results In Thermodynamic Formalism, C. Evans Hedges

Electronic Theses and Dissertations

This dissertation investigates several key questions at the intersection of dynamical systems, computability theory, and thermodynamic formalism. In the symbolic setting, we establish novel results regarding the statistical properties of equilibrium states, deriving bounds on probabilities of configurations and relating these bounds to the Gibbs property through the homoclinic relation. Additionally, we examine the computability of thermodynamic quantities such as pressure, ground state energy, and residual entropy. We show that topological pressure is computable from above for general subshifts and computable for strongly irreducible shifts, with similar results extending to ground state energy and residual entropy.

Extending beyond subshifts, we …

Toward Sustainable Human Well-Being: A Multidimensional Assessment In Colorado, Uma Umut Baysal

Electronic Theses and Dissertations

Evaluating progress in human well-being is essential for guiding effective policy and promoting sustainable development. Traditional approaches often emphasize economic and social dimensions while overlooking ecological indicators critical to long-term sustainability. This research addresses that gap by proposing a layered, scalable local framework for county-level analysis and bottom-up decision-making, integrating multiple objective indicators to assess and compare well-being outcomes across regions.

The first goal of this dissertation is to measure human well-being in Colorado counties by developing a Human Well-Being Index (HWBI). This index combines a newly developed Built Environment Index (BEI) comprising five sub-indices: accessibility, housing affordability, transportation, …

Cultivating Resilience In The Anthropocene: Evaluating A Gssw Ecological Justice Curriculum, Windy Selig

Electronic Theses and Dissertations

This Dissertation in Practice evaluated the University of Denver’s Graduate School of Social Work (GSSW) Ecological Justice Pathway to examine how resilience is conceptualized and cultivated within the curriculum. Grounded in a constructivist paradigm and guided by an ecological justice framework, this evaluation explored the pedagogical and curricular strategies designed to prepare social work students for the emotional, ethical, and professional demands of practicing in the Anthropocene—a time marked by ecological degradation, climate crisis, and compounding social inequities.

Through qualitative methods, including faculty interviews and curriculum document analysis, the evaluation identified both explicit and implicit components that foster student resilience. …

Spatial Analysis Of La Nana Bayou Watershed To Assess Stream Health, Rylee G. Gabbert

Electronic Theses and Dissertations

The purpose of this study was to evaluate the feasibility of using land cover mapping to identify water quality indicators within a river basin, assessing whether this method provides greater efficiency compared to traditional field-based water quality testing. Land cover mapping has efficiently monitored environmental changes by detecting alterations within specific areas. With the La Nana Bayou Watershed positioned in the heart of Nacogdoches City, an urbanized environment; it is subject to human induced alterations that can negatively affect the natural functionality of its system. When water quality indicators are successfully related to land cover maps, changes within the landscape …

Feasibility Analysis For The Implementation Of An Anaerobic Digestion System In The City Of Pittsburgh, Pa, Gianna L. Kolencik

Electronic Theses and Dissertations

The current study is investigating the feasibility of an anaerobic digestion system

in Pittsburgh, Pennsylvania, at the old State Correctional Institute (SCI-Pittsburgh)

located at 1922 Westhall St. This location is immediately upstream of the Allegheny

County Sanitary Authority (ALCOSAN) along the Ohio River. Municipal solid waste

from ALCOSAN may be used as the main form of feedstock. ALCOSAN produced

roughly 36,500 tons of dry sludge in the reporting year 2023-2024. Based on the volume

of dry sludge from ALCOSAN it is estimated that an anaerobic digestion system could

yield approximately 29,930,000 kWh of energy, which is enough to power over …

Impact Of Unconventional Gas Extraction On Tributaries Of Tenmile Creek, Greene County, Pennsylvania: A 12-Year Perspective, Christian L. Beall

Electronic Theses and Dissertations

Much of southwestern Pennsylvania has been central to a rapid increase in development for unconventional natural gas extraction in the past two decades. The continued monitoring of streams over their lifetime as extraction sites is pivotal to understanding the effects of fracking on local waterways and their ability to provide for wildlife and human use. Here, using multiple indices of biotic integrity (IBI), I perform analyses of fish and macroinvertebrate communities as well as water chemistry on two streams, Bates Fork (with shale wells) and Fonner Run (without), as part of a follow-up to work performed there from 2010-2012. Fish …

Evaluating Predictive Models For Predicting Total Score Of Beef Carcasses, Emmanuel Forson

Electronic Theses and Dissertations

The beef industry plays a vital role in global agriculture, with carcass quality and consumer preference being key determinants of market success. This thesis examines predictive modeling techniques for estimating the Total Score of beef carcasses, a composite measure representing yield and quality, primarily used by the Nebraska Cattlemen Association. Using data from the Nebraska Cattlemen’s Foundation Retail Value Steer Challenge (2000–2023), the study compares the performance of First Order Multiple Linear Regression (MLR) with three machine learning techniques: K-Nearest Neighbors (KNN), Random Forest, and Gradient Boosting Machine (GBM).

The analysis focuses on six key predictors: Hot Carcass Weight, Back …

Thin-Film Optical Filters For Selective Transmission And Black-Body Reflection In Pyroelectric Energy Systems., Cedric Cruz Silva

Electronic Theses and Dissertations

Essential to pyroelectric energy systems is the ability for a pyroelectric material to achieve high temperatures rapidly. In pursuit of augmenting this process, several thin-film optical filters were designed for transmitting laser excitation in the near-infrared region, while simultaneously reflecting black-body radiation for pyroelectric materials. Designs include a classical Fabry-Perot structure with gold and tantalum pentoxide, an induced transmittance filter with silica, hafnia, and gold, and an indium-tin-oxide filter with silica, alumina, and ITO. Performance varies depending on the design. The Fabry-Perot filter experimentally showed a maximum transmittance of 42% at 1.04 μm and an infrared reflectance of 98%. The …

New Bayesian Methods For Longitudinal Data Analysis With Complex Dependence Structures., Anish Mukherjee

Electronic Theses and Dissertations

Longitudinal data in real-world settings are frequently found to be heterogeneous and exhibit intricate spatio-temporal dependence structures. Analyzing such complex data to obtain reliable estimation while quantifying uncertainty necessitates using sophisticated Bayesian methodology. In this work, we present novel Bayesian methods developed to address these challenges. We often observe heterogeneity in longitudinal data, where the mean and variance for certain profiles meaningfully differs from the rest. Some profiles may also exhibit outliers at a limited number of measurements. Using a standard mixed effects model, which assumes homogeneity, can lead to overestimating the residual variance and inefficient estimation. In this work, …

Studies Of Pathways To T2d And Interventions Through A Dynamical System Model., Rafiqul Islam

Electronic Theses and Dissertations

Existing mathematical models investigating the progression of type 2 diabetes (T2D) over time primarily focus on glucose, insulin, β-cell mass, and other related factors, while often omitting fatty acids (FA) as an explicit variable—despite FA being a major energy source for the body. There exists a complex network of dynamical interactions among glucose, insulin, FA, and β-cell mass. To gain deeper insights into the metabolic dynamics and pathophysiology of T2D, it is essential to incorporate FA into such models. In this study, we extend the classic Topp’s GIβ model by explicitly incorporating FA and exploring its interactions with glucose, insulin, …

5g Network Slice Vulnerabilities And Exploit Chaining Through Enablers, John Breeden

Electronic Theses and Dissertations

Network slicing provides fundamental support for the enhanced features of 5G. Network slicing enablers, such as software-defined networking and network function virtualization facilitate the separation of the physical distributed infrastructures and the functions that create isolated slices. With this framework, the network slice is no longer under the control of a single entity. Multiple infrastructure providers share responsibility for the slice. The 5G architecture derives from multiple services, distributed over great distances, and managed by multiple parties. Each enabler and provider adds vulnerability to network slicing. We examine the interweaving of these enablers to identify vulnerabilities, discuss potential mitigation, and …