Digital Commons Network^™

Multi-Objective Optimization Strategy For Component Sizing In Solar-Hydrogen Microgrids Using An Advanced Hybrid Genetic Algorithm, Dylan Jones

UNF Graduate Theses and Dissertations

This thesis presents the development of a genetic algorithm (GA) optimization framework for the design and component sizing of hybrid solar-hydrogen microgrids. The framework addresses a critical gap in research and existing commercial tools by unifying performance maximization and cost minimization objectives across both grid-tied and islanded configurations. Integrating solar photovoltaics, electrolyzers, hydrogen storage, fuel cells, and batteries, the GA employs adaptive weighting and dynamic boundary constraints to balance technical feasibility with economic efficiency. To ensure real-world viability, the algorithm relies on a novel Daylight Sun Factor (DSF) for localized solar assessment and was rigorously validated against multi-year, high-fidelity irradiance …

Mechanical Behavior Of Additively Manufactured Ti-6al-4v Eli Parts: Effects Of Laser Parameter Selection, Samuel Lopez

UNF Graduate Theses and Dissertations

Additive manufacturing (AM) of TI-6AL‑4V Extra‑Low Interstitial (ELI) enables complex geometries for fatigue‑critical medical device applications, yet fatigue performance remains sensitive to process‑induced defects. This work investigates the effect of laser process parameter selection on the microstructure, mechanical properties, and fatigue behavior of TI- 6AL‑4V ELI fabricated via laser powder bed fusion (L‑PBF) using a Renishaw RenAM system. The influence of laser parameters was isolated by holding powder chemistry, build orientation, scan strategy, sub‑transus annealing, and post‑processing constant between a non‑optimized baseline and an optimized parameter set selected based on tensile performance.

Optical microscopy showed the optimized condition exhibited improved …

Performance Of Numerical Methods Applied To The Black–Scholes Model, Scott Cameron Williams

UNF Graduate Theses and Dissertations

We compare five numerical approaches for approximating solutions to the Black–Scholes partial differential equation for pricing European call options: FTCS, BTCS, Crank– Nicolson, Monte Carlo simulation, and a physics–informed neural network (PINN). These methods span finite difference techniques, probabilistic simulation, and machine learning. Performance is evaluated based on computational efficiency and accuracy relative to the analytical Black–Scholes solution.

Among the methods, Crank–Nicolson and the PINN demonstrated the strongest overall performance. Crank–Nicolson achieved the highest accuracy but exhibited increased runtime as the number of underlying stock price grid points grew. In contrast, the PINN produced slightly less accurate results but with …

Effects Of Pressure-Based Virtual Reality Training On Mental Toughness In Athletes, Rylee J. Aspinwall

UNF Graduate Theses and Dissertations

Athletes often underperform in high-pressure situations due to challenges in emotional regulation rather than deficits in physical skill. Mental toughness, broadly defined as the ability to maintain performance under stress, is a key determinant of athletic success but remains difficult to train using traditional methods. Virtual reality (VR) offers a controlled and immersive environment for simulating competitive pressure; however, its application for training mental toughness remains limited. The present study examined the effects of pressure-based VR training on psychological and physiological responses in collegiate baseball and softball athletes. Participants completed up to eight VR training sessions under either high-pressure or …

Don't Crash Out: The Effects Of Personality And Social Support On Subjective Stress Responses And Heart Rate Variability, Nicholas Kilpatrick

UNF Graduate Theses and Dissertations

The present study examined the relationship between personality traits, physiological stress responses, and subjective stress during a social-evaluative stress task, as well as the potential mediating role of heart rate variability (HRV) and moderating role of imagined social support. Participants completed a laboratory-based modified Trier Social Stress Task while HRV was continuously recorded, and self-reported stress was assessed across task phases. Results indicated that neuroticism and protective self-monitoring were associated with higher levels of subjective stress, while acquisitive self-monitoring was associated with greater reductions in stress following the task. Neuroticism was also associated with greater increases in HRV during the …

A Comparative Evaluation Of Data Imbalance Handling Techniques In Machine Learning Models For One-Year Mortality Prediction In Liver Cirrhosis, Sumiya Hasan Trisha

UNF Graduate Theses and Dissertations

Liver cirrhosis is associated with substantial morbidity and mortality, making one-year mortality prediction a clinically relevant problem. Using a liver cirrhosis dataset as the motivating application, this thesis evaluates five machine learning classifiers—Logistic Regression, Random Forest, XGBoost, LightGBM, and CatBoost—under five class-imbalance handling strategies: Baseline learning, Random Oversampling, SMOTE-NC, ADASYN, and Cost-Sensitive Learning. Hyperparameter tuning was conducted using randomized search, and predictive performance was assessed over 200 iterations of Monte Carlo Cross-Validation using Accuracy, Precision, Recall, Fl-score, and ROC-AUC.

The results suggest that imbalance-handling strategies can materially affect predictive performance, particularly recall. Because the outcome of interest is death within …

Variance Shrinkage In Dunnett-Type Multiple Comparisons With Missing Data, Md Habibullah

UNF Graduate Theses and Dissertations

Dunnett’s procedure is widely used for comparing multiple treatments with a control, but its application becomes challenging in the presence of missing data and multiple com- parisons. An improved Dunnett-type procedure addresses this by using multiple imputation under Rubin’s framework and constructing unified confidence intervals based on a multi- variate t distribution, allowing valid simultaneous inference while controlling the family-wise error rate (FWER). This work further extends the method by incorporating shrinkage-based variance estimation. Specifically, individual group variances are shrunk toward a common value to improve stability. This approach is particularly effective when group variances are similar or moderately different, …

Ridit-Based Adaptive Allocation In Two-Stage Clinical Trials With Binary Outcomes, Dewan Fahim

UNF Graduate Theses and Dissertations

This study explores better ways to assign patients to treatments in clinical trials with binary outcomes, such as success or failure. Adaptive methods are used to learn from early results and adjust treatment assignments during the trial, helping more patients receive better performing treatments while maintaining reliable conclusions. We focus on trials comparing multiple treatments using a two-stage design. In the first stage, several treatments are tested to identify the most promising one; in the second stage, that treatment is compared with a control. Unlike traditional equal assignment, we use adaptive allocation in the second stage to make better use …

A Comparative Study Of Classification Methods For Healthcare Analytics, Xueting Zhao

UNF Graduate Theses and Dissertations

This thesis presents a comparative study of logistic regression, Linear Discriminant Analy- sis (LDA), and Quadratic Discriminant Analysis (QDA) for binary classification in healthcare analytics, integrating theoretical derivation, simulation, and real-data application. A facto- rial simulation study crosses the covariance structure (equal vs. unequal), predictor correla- tion (ρ ∈ {0, 0.5, 0.9}), dimensionality (p ∈ {2, 5, 10}) and sample size (n ∈ {50, 100, 200}) across 54 scenarios with 1,000 Monte Carlo replicates each. Three main findings emerge. Logistic regression and LDA are nearly interchangeable when the assumption of equal-covariance holds. QDA achieves substantially better discrimi- nation when class-specific …

Parental Distress, Coercive Control With Food, And Child Self-Regulation, Kattie Nguyen

UNF Graduate Theses and Dissertations

Self-regulation is the management of one's emotions, thoughts, and behaviors to adapt to a situation (Smith-Donald et al., 2007). During infancy and toddlerhood, parents foster self-regulation through co-regulation (e.g., sensitivity, responsiveness), helping children manage their emotions, behaviors, and thoughts (Butler & Randall, 2013). Parents who experience distress (e.g., depression, stress, anxiety) are more likely to use less responsive and harsher, controlling practices like coercive control. Coercive control with food is a practice where parents use food as threats or bribes to control their child’s emotions and behaviors (Vaughn et al., 2016). The present study examined the associations between parental distress, …

Social Support, Trauma And Neurophysiological Stress, Devon S. Glicken

UNF Graduate Theses and Dissertations

Traumatic life experiences and the prolonged effects of stress can negatively impact an individual’s mental and physical health. Hyperreactivity to acute stressors can often be seen in individuals with anxiety, depression, and suicidal ideations, conditions commonly observed with endocrine dysfunction. How do traumatic experiences, particularly experiences related to military affiliation, influence stress responses and feelings of burdensomeness and thwarted belongingness? This study predicted (1) that military-affiliated individuals (and those with PTSD symptomology and high perceived life stress) will have heightened neurophysiological responses to minor levels of acute stress compared to individuals without military-affiliations (and those without PTSD symptomology or high …

Two-Stage Response-Adaptive Randomization Designs For Multi-Arm Trials With Normal Outcome, Tanjin Tamanna Happy

UNF Graduate Theses and Dissertations

This study focuses on improving how clinical trials compare new treatments with a standard treatment, when the response is quantitative (normally distributed). In a common two-stage design, several new treatments are first evaluated, and the best-performing one is selected if it appears better than the standard. In the second stage, this selected treatment is compared again with the standard using additional data to confirm its effectiveness. This approach is known to be efficient in terms of accuracy and sample size savings. We extend this design by introducing an adaptive method for assigning patients to treatments in the second stage. Instead …

The Effect Of Coercive Control With Digital Devices On Emotion Regulation In Preschool-Age Children: An Experimental Approach, Gina Burroughs

UNF Graduate Theses and Dissertations

The experiment was an investigation on the differences in child emotion regulation between two groups during a disappointing gift task. Fifteen four-to-five-year-olds were randomly assigned to either receive coercive control with a digital tablet or an emotion-coping intervention. All children received a disappointing gift a second time as emotion regulation strategies (cognitive reframing, self-soothing, comfort-seeking) were recorded. A χ² test revealed a nonsignificant difference between frequency of post-manipulation emotion regulation strategies. Three cognitive-reframing subtypes were coded and an independent-samples t-test revealed between-group differences approaching significance, suggesting that adults can teach cognitive reframing to this age range. Additional analysis revealed …

Experimental Validation Of Optical Wireless Communication And Power Transfer For Uav Applications, Fnu Dhruv

UNF Graduate Theses and Dissertations

Unmanned Aerial Vehicles (UAVs) have revolutionized emergency response, disaster assessment, and search-and-rescue operations. However, their operational efficacy is fundamentally constrained by limited battery endurance and the susceptibility of traditional radio-frequency communication to disruption in adverse weather. To address these limitations, this thesis proposes and experimentally validates a novel architecture integrating Free-Space Optical (FSO) communication with Simultaneous Lightweight Information and Power Transfer (SLIPT). This system utilizes a split-beam configuration to concurrently enable high-bandwidth data transmission and optical energy harvesting to replenish the UAV's battery pack. The research was conducted in three progressive phases. Initially, system feasibility was established through rigorous optical …

Widowed And Wounded? Exploring The Health Impacts Of Adverse Childhood Experiences In Later Life Widowhood, Sierra Wickline

UNF Graduate Theses and Dissertations

Losing a spouse is considered one of the most stressful life events that disproportionately affect older individuals. Exposure to traumatic events at an early age can change the body’s response to subsequent stressors across the lifespan. These physical changes often impact people’s health. Utilizing data from the Health and Retirement Study, the current study aimed to investigate the link between: adverse childhood experiences (ACEs) and three indicators of health: inflammation (i.e., c-reactive protein [CRP], reflecting immune functioning), as well as self-reported depressive symptoms and physical health, among people who have lost a spouse. Participants included 97 widowed individuals aged 68 …

A Stability Analysis Of The Phase-Lock Equations, Brian M. Sunguza

UNF Graduate Theses and Dissertations

Ginzburg and Landau have provided a set of equations that relate superconductivity to magnetic fields. Through a transformation process, Zhan has derived what are now called the phase-lock equations. A stability analysis of the spatially-independent phase-lock equations is the purpose of this presentation. This simplification is significant since it allowed for the analytical determination of equilibria, their stability, and the influence of a periodic forcing function. Through the use of an original code, numerical simulations are shown to corroborate the analytical results described above.

This analysis includes novel Lyapunov functions that allowed for the analytical determination of the instability region. …

The Effects Of Weathering On The Very High Cycle Fatigue Behavior Of Aluminum 6061-T6, Rama Albatesh

UNF Graduate Theses and Dissertations

Aluminum 6061-T6 is commonly used in structural and transportation applications due to its strength-to-weight ratio, corrosion resistance, and ease of manufacturing. In many practical situations, components made from this alloy experience cyclic loading while exposed to environmental conditions such as humidity, temperature changes, and ultraviolet radiation. These factors can affect surface integrity and fatigue performance, especially in the very high-cycle fatigue (VHCF) regime.

This study aims to explore how accelerated weathering impacts the ultrasonic fatigue behavior of Aluminum 6061-T6. First, assess the material through tensile testing to determine its mechanical properties. Then conducted microstructural analysis using optical microscopy, scanning electron …

Energy-Efficient Security For Narrowband Iot Using Blockchain And Ep-Cumac, Hafizullah Kakar

UNF Graduate Theses and Dissertations

The Narrowband Internet of Things (NB-IoT) continues to expand but faces challenges such as cryptographic overhead and energy consumption. Security frameworks such as blockchain and Energy-Performance Cumulative Message Authentication Codes (EP-CuMAC) rely heavily on SHA-256, which is not optimized for energy-limited devices.

This work unifies two complementary approaches, a hybrid blockchain-based NB-IoT framework and an EP-CuMAC-based framework, by engineering their cryptographic core with an Energy Complexity Model-optimized SHA-256 (ECM-SHA256). ECM applies parallel memory-bank mapping and block-level access optimization to reduce redundant power usage while preserving algorithmic integrity.

Experimental evaluation on identical Intel DDR3 systems using pyRAPL shows energy savings of …

Towards All-Epitaxial Josephson Junctions With High-Temperature Superconductors, Daniela Amalfi Ojeda

UNF Graduate Theses and Dissertations

Josephson junctions are fundamental components of superconducting electronics. Although junctions based on conventional superconductors are well established, reproducible devices based on high-temperature superconductors remain challenging. This work investigates the growth, fabrication, and electrical characterization of all-epitaxial DyBa₂Cu₃O₇₋ₓ (DBCO) /SrTiO₃ (STO) /DBCO trilayer heterostructures for potential Josephson junction applications. An initial optimization of YBa₂Cu₃O₇₋ₓ (YBCO) growth produced reproducible films with a zero-resistance critical temperature ( ) of K and a maximum  of 89 K. These growth conditions were adapted to DBCO, resulting in reproducible superconducting films with values of approximately 80 K. DBCO/STO/DBCO trilayers were grown by molecular beam epitaxy and …

Growth And Dielectric Characterization Of Epitaxial Sr1-Xmgxtio3 Thin Films, Richard Badu

UNF Graduate Theses and Dissertations

Complex oxide materials with ferroelectric ground states remain promising candi dates for next-generation high-capacitance and nonlinear microelectronic applica tions. One of those materials is SrTiO3 (STO). However, STO is an incipient fer roelectric with anomalously high dielectric permittivity at low temperatures. STO crystals possess a highly polarizable lattice that is sensitive to even small amounts of impurities. Substituting Mg into the STO matrix is predicted to induce a corre lation between ferroelectric and relaxor behavior. In this thesis, we demonstrated the growth of a series of epitaxial STO and Sr1-xMgxTiO3 thin films using molec ular beam epitaxy. The surface evolution …

Development And Testing Of A Low-Cost Inertial Impact Sensor, Gabriel Michael Pesek

UNF Graduate Theses and Dissertations

Acceleration sensors have seen increasing usage within sports to detect when somebody receives an impact to their head which can potentially lead to Traumatic Brain Injury (TBI). While adoption of these sensors has steadily risen, the cost of these sensors is often cited as a reason they have not been as widely adopted, especially for amateur teams. This leads to the need for a lower-cost option for detecting these impacts. To fill this gap, a low-cost, lightweight acceleration sensor was designed that exploits the inertia of a working fluid on impact in order to rupture a metallic membrane which acts …

Thermomechanical Modeling Of Transpiration Surfaces For Hypersonic Propulsion, Spencer D. Smith

Graduate Studies Theses and Dissertations 2026

Hypersonic flight vehicles are a promising form of high speed passenger transport and efficient space access architectures. However, they are fundamentally a thermally limited technology. High heat fluxes exceeding 10 MW/m2 and gas temperatures between 3000-4000K can be found both within the engine, and on the outer surface. Current conventional engineering materials are non-viable at these conditions. In order to make these materials viable, active cooling strategies could be utilized. One particularly promising type is transpiration cooling, where a coolant is diffused through a porous surface. Although researched heavily in the 1960s, adoption is still minimal. Part of the reason …

Examining Relationships Between Pre-Arrival Information, Perceived Preparedness, And Distressing Call Outcomes Among Firefighters, Victoria L. Steigerwald

Graduate Studies Theses and Dissertations 2026

Responding to distressing emergency calls increases firefighters’ risk for negative mental health outcomes, including posttraumatic stress disorder, warranting investigation into factors that can be targeted to reduce their risk for call-related distress. The present study examined whether the completeness of pre-arrival information about a distressing call reduced firefighters’ peri- and post-call distress via their perceived preparedness for the call and whether general self-efficacy moderated the relationship between pre-arrival information completeness and perceived preparedness. Data were analyzed from 173 active firefighters in the United States (89.0% male, mean age=37.98 years) who completed an online survey asking them to report on levels …

Experimental Characterization Of Obstacle-Driven Ddt And The Performance Of Relief Dump Tanks In Detonation Systems, Bryan Suarez

Graduate Studies Theses and Dissertations 2026

This study investigates the lifecycle of a detonation event in a modular detonation
tube facility. It focuses on the mechanisms of deflagration-to-detonation transition
(DDT) and the effectiveness of a pressure relief system. With a stoichiometric
hydrogen-oxygen mixture, the research aims to characterize the effect of
interchangeable turbulator obstacles on the DDT process. By varying blockage
ratios and obstacle geometries in the pre-detonation section. This study identifies
how physical characteristics influence transition efficiency. The experimental data
collected includes pressure spikes and wave speed which were then used to
validate against the Chapman-Jouguet (CJ) theory at initial pressures of 350 Torr
and …

Federated Learning In The Era Of Foundation Models, Guangyu Sun

Graduate Studies Theses and Dissertations 2026

The emergence of large-scale foundation models has reshaped computer vision and multi-modal learning, but their substantial computational and communication demands pose significant challenges for deployment in federated learning (FL) systems. Federated learning enables collaborative model training across decentralized clients without sharing raw data, offering strong privacy guarantees. However, adapting foundation models in FL remains difficult due to communication bottlenecks, heterogeneous data distributions, limited device resources, and scarce labeled data. This dissertation presents a unified line of research that addresses these challenges through four complementary frameworks, progressively advancing the efficiency, personalization, and practicality of foundation model adaptation in federated settings.

First, …

Building Eden Where We Can, Ireland Thomas

Graduate Studies Theses and Dissertations 2026

Building Eden Where We Can is a nonfiction memoir told in vignettes that come together to build a wider story. Through these vignettes, we are shown a narrator who is simultaneously surviving an abusive family, navigating a rare diagnosis, and coming to terms with their queerness. By braiding narratives and maintaining these various threads, this collection examines the intersections of sickness and religion, tradition and freedom, as well as fear and love. The lattermost dichotomy is represented in the narrator’s ultimate choice to leave behind a life of fear in the mother figure’s safe cage. In exchange, they receive a …

Abig4l: A Semantic Reasoning Engine For Verilog Via Abstract Interpretation, Alicia Thoney

Graduate Studies Theses and Dissertations 2026

Modern Electronic Design Automation (EDA) flows treat structural and semantic reasoning as separate concerns. Synthesis structurally optimizes RTL, while dedicated verification teams validate functional behavior through testbenches and formal methods. This organizational divide means designers have no automatic, sound way to understand what their RTL does at the moment they are writing it. This thesis introduces AbIG4L (Abstract Interpretation of Generic 4-valued Logic), a static analysis framework that bridges this gap by delivering sound semantic reasoning automatically, directly within the hardware design loop.

The framework operates on a language-agnostic intermediate representation to compute sound over-approximations of hardware behavior across 0, …

The Reliability, Validity, And Sensitivity Of Physical Working Capacity At The Pain Intensity Threshold, Danielle A. Sterner

Graduate Studies Theses and Dissertations 2026

The purpose of this dissertation was to evaluate the reliability, validity, and responsiveness to training intervention of a pain-anchored capacity threshold, the Physical Working Capacity at the Pain Intensity Threshold (PWC_PIT), as a practical submaximal marker of endurance-related exercise tolerance. Study one examined the test-retest reliability of pain-based, perceptual, and physiological physical working capacity measures in recreationally active men using a standardized multi-bout cycling protocol, with pain intensity responses demonstrating strong reproducibility and low measurement error, supporting the stability of pain-anchored thresholds when standardized procedures are applied. Study two evaluated the validity of PWC_PIT by examining pain …

Chirpi - Implementing And Analyzing The Chirp Communication Algorithm On Esp32 Hardware, Calvin Vanwormer

Graduate Studies Theses and Dissertations 2026

This work presents the implementation and experimental evaluation of the CHIRP communication algorithm on resource-constrained ESP32-S3 microcontrollers, bridging the gap between simulation-based validation and real-world deployment. CHIRP is a lightweight, fully decentralized peer-to-peer protocol designed for IoT networks with dynamic node membership, enabling runtime node join and leave operations without centralized coordination or global reconfiguration. The implementation comprises two main components: C-based node firmware running on FreeRTOS [1, 2], which implements the full CHIRP protocol including peer discovery, round-robin pairing, and firefly-inspired phase synchronization, and a Python-based experiment controller that orchestrates network experiments and collects per-node metrics without influencing protocol …

Watch Your Step, Mind The Crowd: Socially Compliant Navigation In Unstructured Environments, Jack Vice

Graduate Studies Theses and Dissertations 2026

Autonomous mobile robots increasingly operate in complex real-world environments characterized by uneven terrain, dynamic obstacles, and human presence. This dissertation addresses the fundamental challenge of developing adaptive navigation strategies that enable robots to safely and effectively traverse unstructured outdoor environments including construction sites, agricultural fields, and disaster areas while maintaining social compliance around people. We advance this capability through five complementary contributions that collectively target dynamic, unstructured, human-occupied environments. First, we demonstrate evolutionary optimization of legged mobility for uneven terrain. Second, we propose using a spatiotemporal autoencoder to learn the temporal dynamics of moving people and objects. Third, we introduce …