Digital Commons Network^™

Generalized Vulnerability Measures Of Graphs, Julia Vanlandingham

All Theses

Several measures of vulnerability of a graph look at how easy it is to disrupt the network by removing/disabling vertices. As graph-theoretical parameters, they treat all vertices alike: each vertex is equally important. For example, the integrity parameter considers the number of vertices removed and the maximum number of vertices in a component that remains. We consider the generalization of these measures of vulnerability to weighted vertices in order to better model real-world applications. In particular, we investigate bounds on the weighted versions of connectivity and integrity, when polynomial algorithms for computation exist, and other characteristics of the generalized measures.

The Effects Of The Esol Program On African American Vernacular Speaking Students Reading, Marquice Clark

All Dissertations

South Carolina’s public education system is broken. For the past several years, the State of South Carolina and the nation have somehow managed to do the nearly impossible. Both have produced more English Language Learning (ELL) students to be proficient in English Language Arts (ELA) (i.e., reading, writing, and usage) than native English speakers. The issue of low black performance on state and national standardized assessments has always been a cumbersome task for America's public school system. Although Black students comprise more than 30 percent of the total student population in America, more Limited English students are demonstrating a higher …

A Deeper Understanding Of The R Process, Mengke Li

All Dissertations

The overarching aim of my PhD research is to deepen our understanding of r-process nu- cleosynthesis. The initial phase of my work involved developing a Machine Learning-based nuclear mass model, specifically tailored to predict nuclear masses crucial for r-process nucleosynthesis. This model was then applied to simulate the r-process, focusing on neutron-rich nuclei significant to nucleosynthesis. The simulations yielded r-process abundance patterns, extending up to thorium and uranium, that align qualitatively with the observed solar system abundance patterns, with the characteristic peaks well positioned. Advancing our study further, we introduced a novel graph-based methodology named GrRproc for calculating r-process abundances. …

Controlled Manipulation And Transport By Microswimmers In Stokes Flows, Jake Buzhardt

All Dissertations

Remotely actuated microscale swimming robots have the potential to revolutionize many aspects of biomedicine. However, for the longterm goals of this field of research to be achievable, it is necessary to develop modelling, simulation, and control strategies which effectively and efficiently account for not only the motion of individual swimmers, but also the complex interactions of such swimmers with their environment including other nearby swimmers, boundaries, other cargo and passive particles, and the fluid medium itself. The aim of this thesis is to study these problems in simulation from the perspective of controls and dynamical systems, with a particular focus …

Femtosecond Laser Shock Peening And The Dynamics Of Femtosecond Laser-Induced Shock Waves, Yuxin Li

All Dissertations

Laser shock peening (LSP) is an important material surface strengthening technique that uses laserinduced shock waves to cause severe plastic deformation near material surfaces. It can significantly improve material properties like hardness, strength, fatigue life, and corrosion resistance and is widely used in industrial sectors such as automotive, aerospace, nuclear, and medical areas. The conventional nanosecond laser shock peening (ns-LSP) has demonstrated effectiveness but faces challenges such as complex setup, low throughput, high energy consumption, and inflexibility for complex geometries. Femtosecond laser shock peening (fs-LSP) offers a promising alternative to overcome these issues, thanks to its ultra-high laser intensity and …

Impacts Of Connected And Automated Vehicles On Energy And Traffic Flow: Optimal Control Design And Verification Through Field Testing, Tyler Ard

All Dissertations

This dissertation assesses eco-driving effectiveness in several key traffic scenarios that include passenger vehicle transportation in highway driving and urban driving that also includes interactions with traffic signals, as well as heavy-duty line-haul truck transportation in highway driving with significant road grade. These studies are accomplished through both traffic microsimulation that propagates individual vehicle interactions to synthesize large-scale traffic patterns that emerge from the eco-driving strategies, and through experimentation in which real prototyped connected and automated vehicles (CAVs) are utilized to directly measure energy benefits from the designed eco-driving control strategies. In particular, vehicle-in-the-loop is leveraged for the CAVs driven …

Deep Reinforcement Learning For The Design Of Structural Topologies, Nathan Brown

All Dissertations

Advances in machine learning algorithms and increased computational efficiencies have given engineers new capabilities and tools for engineering design. The presented work investigates using deep reinforcement learning (DRL), a subset of deep machine learning that teaches an agent to complete a task through accumulating experiences in an interactive environment, to design 2D structural topologies. Three unique structural topology design problems are investigated to validate DRL as a practical design automation tool to produce high-performing designs in structural topology domains.

The first design problem attempts to find a gradient-free alternative to solving the compliance minimization topology optimization problem. In the proposed …

An Investigation Of The Accretion Processes In T Tauri And Herbig Ae/Be Systems Using High Resolution Optical And Near-Infrared Spectroscopy, Joshua Kern

All Dissertations

Star and planet formation is intimately tied to the accretion of material from the environments in which they form. During the formation process, disks of gas and dust develop in young stellar objects through which material is facilitated to the star and forming planets. Theoretical models of these accretion processes invoke viscous spreading via hydrodynamics, as well as more complex interactions with magnetic fields be it from the stellar component or the formation environment in order to catalyze these mass flows. These accretion models predict various scenarios including magnetospheric accretion as well as supersonic accretion flows in the disk atmosphere …

Estimating Financial And Environmental Risk: Some New Developments And Comparison Study., Fnu Kamronnaher

All Dissertations

This dissertation delves into the concept of risk, specifically focusing on two prominent categories: financial risk and environmental risk.

Financial risk is the probability of unfavorable outcomes of an investment while environmental risk refers to the possible harm to the environment resulting from extreme weather events. More specifically, risk is the high (low) quantiles of the distribution of variables of interest. \\ To quantify and assess uncertainties in financial and environmental risk, robust and reliable methodologies are needed. The aim of this dissertation is to develop some risk assessment methods and compare them with the widely used methodologies in both …

A Survey Of Code-Based Cryptography, Antsa Rakotondrafara

All Theses

One of the biggest concerns of the digital era is to keep data secure. With the rise of quantum computers, some of the problems that were considered hard will be solved in polynomial time. Therefore, efforts are taken to design practical cryptosystems that will resist attacks from both classical computers and quantum computers. In this thesis, we analyze three quantum-resistant code-based cryptosystems. We propose a new type of attack based on mixed-integer non-convex programming for the NIST submission FuLeeca.

Converging Human Intelligence With Ai Systems To Advance Flood Evacuation Decision Making, Rishav Karanjit

All Theses

The powers that artificial intelligence (AI) has developed are astounding, with recent success in integrating into a human cognitive workflow. AI will attain its full potential only if, as part of its intelligence, it also actively teams up with humans to co-create solutions. Combining AI simulation with human understanding and strategic abilities through data convergence may optimize the process and provide a capacity akin to "teaming intelligence." This thesis will introduce the concepts of Human AI Convergence (HAC) capabilities for flood evacuation decision-making. The concept introduced in this thesis is the first step toward the HAC concept in weather disaster …

Material World, Nicole Weldy

All Theses

My thesis, Material World, delves into the use of the crochet unit as a construction technique for building forms. Through this, I aim to organize different materials in a way that responds to the challenges posed by the physical world. My artistic process is centered around honoring the inherent qualities of thread and uses these qualities to create form, lightness, and linearity. At the same time, I remain receptive to transformative processes such as combining three-dimensional (3D) printed lines and lace stiffener to push the boundaries of what thread can do. By combining manual craftsmanship with technology materialized as …

Dynamic Translation Of Drone View To Vehicle View For Autonomous Driving, Grayson Byrd

All Theses

As the field of computer vision continues to advance, the use of autonomous vehicles in military applications has increased and the tasks associated with these systems have grown in scope and complexity. These vehicles tend to operate in combat situations, presenting significant risk in the form of sensor damage. Since these autonomy algorithms rely on sensor information to navigate their environment, any threat to sensor functionality negatively impacts the reliability of the system. As a potential solution, I propose Dynamic Diffusion-based View Translation (DDVT), a novel computer vision algorithm capable of restoring image sensor function in ground vehicles through aerial …

Safe Navigation Of Quadruped Robots Using Density Functions, Andrew Zheng

All Theses

Safe navigation of mission-critical systems is of utmost importance in many modern autonomous applications. Over the past decades, the approach to the problem has consisted of using probabilistic methods, such as sample-based planners, to generate feasible, safe solutions to the navigation problem. However, these methods use iterative safety checks to guarantee the safety of the system, which can become quite complex. The navigation problem can also be solved in feedback form using potential field methods. Navigation function, a class of potential field methods, is an analytical control design to give almost everywhere convergence properties, but under certain topological constraints and …

Model-Free Methods To Analyze Pmu Data In Real-Time For Situational Awareness And Stability Monitoring, Sean Kantra

All Dissertations

This dissertation presents and evaluates model-free methodologies to process Phasor Measurement Unit (PMU) data. Model-based PMU applications require knowledge of the system topology, most frequently the system admittance matrix. For large systems, the admittance matrix, or other system parameters, can be time-consuming to integrate into supporting PMU applications. These data sources are often sensitive and can require permissions to access, delaying the implementation of model-based approaches. This dissertation focuses on evaluating individual model-free applications to efficiently perform functions of interest to system operators for real-time situational awareness. Real-time situational awareness is evaluated with respect to central digitization where the PMU …

From Experiences To Beliefs: An Exploratory Case Study On Science Teachers’ Attitudes Towards Emergent Bilinguals, Yamil Ernesto Ruiz

All Dissertations

Emergent bilingual (EB) students in the US are those who are in the process of developing academic English proficiency. EBs are some of the fastest growing populations of students in American public schools. There exists a great deal of research geared towards developing both curricular resources and instructional strategies to best support EBs in the science classroom, however many of these professional development studies lament the lack of growth in terms of achievement in science learning outcomes of EBs. It is possible that due to a lack of transformation in their beliefs that the teachers in these studies do not …

Interpretable Mechanistic And Machine Learning Models For Pre-Dicting Cardiac Remodeling From Biochemical And Biomechanical Features, Anamul Haque

All Dissertations

Biochemical and biomechanical signals drive cardiac remodeling, resulting in altered heart physiology and the precursor for several cardiac diseases, the leading cause of death for most racial groups in the USA. Reversing cardiac remodeling requires medication and device-assisted treatment such as Cardiac Resynchronization Therapy (CRT), but current interventions produce highly variable responses from patient to patient. Mechanistic modeling and Machine learning (ML) approaches have the functionality to aid diagnosis and therapy selection using various input features. Moreover, 'Interpretable' machine learning methods have helped make machine learning models fairer and more suited for clinical application. The overarching objective of this doctoral …

Studies On Electrochemical Hydrogen Isotope Separation, Liyanage Mayura Sankalpa Silva

All Dissertations

Graphene-integrated Proton Exchange Membrane (PEM) electrochemical cells have emerged as a novel area of scientific investigation in the realm of hydrogen isotope separation. Chemical Vapor Deposited (CVD) graphene has been especially useful due to its large-scale production capability for scaling-up purposes. The research described in this dissertation explores the role that inadvertent introduction of cations, notably ammonium and copper, during the CVD graphene transfer onto PEM substrates, such as Nafion, might play in affecting hydrogen ion transport and isotope separation in PEM electrochemical cells. An extensive review of existing literature exposed a gap concerning unintentional cation introductions during graphene transfer, …

Ti-6al-4v Β Phase Selective Dissolution: In Vitro Mechanism And Prediction, Michael A Kurtz

All Dissertations

Retrieval studies document Ti-6Al-4V β phase dissolution within total hip replacement systems. A gap persists in our mechanistic understanding and existing standards fail to reproduce this damage. This thesis aims to (1) elucidate the Ti-6Al-4V selective dissolution mechanism as functions of solution chemistry, electrode potential and temperature; (2) investigate the effects of adverse electrochemical conditions on additively manufactured (AM) titanium alloys and (3) apply machine learning to predict the Ti-6Al-4V dissolution state. We hypothesized that (1) cathodic activation and inflammatory species (H₂O₂) would degrade the Ti-6Al-4V oxide, promoting dissolution; (2) AM Ti-6Al-4V selective dissolution would occur …

The Power Of Play: The Role Of Children’S Museums In Kindergarten Readiness, Catie Davis

All Dissertations

This study explores the transformative potential of play in preparing young children for Kindergarten, focusing on the intersection of children's museums, caregiver interactions, and school readiness. The study, conducted over an eight-week Pop-Up Classroom program at The Flowerfield Children's Museum, included 52 participants, primarily from low-income backgrounds. Through a mixed-methods approach, including participant observations and caregiver surveys, the research aimed to answer the fundamental question: What is the role of play in preparing children for Kindergarten?

Two significant findings emerged. Firstly, the study illuminated the pivotal role of play in nurturing social-emotional development and communication skills among children. Structured observations …

Leveraging Artificial Intelligence For Team Cognition In Human-Ai Teams, Beau Schelble

All Dissertations

Advances in artificial intelligence (AI) technologies have enabled AI to be applied across a wide variety of new fields like cryptography, art, and data analysis. Several of these fields are social in nature, including decision-making and teaming, which introduces a new set of challenges for AI research. While each of these fields has its unique challenges, the area of human-AI teaming is beset with many that center around the expectations and abilities of AI teammates. One such challenge is understanding team cognition in these human-AI teams and AI teammates' ability to contribute towards, support, and encourage it. Team cognition is …

Atomistic And Mesoscale Modeling Of Microstructure Development During Solid-State Sintering, Omar Hussein

All Dissertations

Interfaces are ubiquitous in materials systems, and they influence the processing and properties of nearly all engineering and functional materials. Examples include grain boundaries (GBs) in polycrystalline materials, free surfaces in nanoparticles, and phase boundaries in multiphase materials. Therefore, understanding and controlling interfacial processes is a key aspect of materials design and discovery efforts.

Recent developments in advanced manufacturing and synthesis techniques have enabled the fabrication of materials architectures with intricate nanoscale features. Of particular interest is solid-state sintering, known for creating complex and high-precision geometries with controlled microstructures. While sintering science has been the subject of active research, very …

Experimental And Computational Platforms For Studying Systems Mechanobiology, Brendyn Miller

All Dissertations

Mechanical stimulation through physical activity has been shown to play an important role in treating and preventing several non-communicable diseases such as hypertension, lower back pain (LBP), type-2 diabetes mellitus, and several cancers. This is accomplished through the regulation of cellular behavior and tissue remodeling within the body at both the micro- and macro-scale levels. The goal of mechanobiology research is to gain in-depth knowledge and understanding of how cells sense physical forces in conjunction with other biochemical cues and translate those factors into important biological functions that either maintain tissue homeostasis or lead to pathological states. Understanding these processes …

Leveraging Professional Learning To Impact Leadership Of Technology Integration, Tennille Woodward

All Dissertations

School and district leaders lack awareness of the depth and complexity of the International Society for Technology in Education (ISTE) Standards for Education Leaders and how the implementation of the leader standards provides for students and teachers to learn relevant skills and strategies. Continuing the work of Schoenbart’s 2019 dissertation, the Education Leaders Technology Survey (ELTS) provides a self-assessment for education leaders to reflect on their leadership of technology integration and provides baseline data for this study. Professional learning around the ISTE Standards for Education Leaders provided through a Canvas course provides education leaders with a theory of action to …

Hydrothermal Synthesis Of First-Row Transition Metal Polyanions Towards The Design Of Frustrated Magnetic Materials, Megan Smart

All Dissertations

Novel modern materials are constantly being discovered as humanity seeks constantly better improvement to the optics and electronics around us, from lasers used in medical therapies to the magnets and supercomputing chips in our phones. Inorganic oxides commonly draw inspiration from naturally occurring minerals to template new discoveries through substitution of similarly behaving elements with the goal of inducing certain desired properties, such as ferroelectricity or creating the elusive quantum spin liquid. While many minerals are silicates, its periodic table neighbor germanium(IV) has a rich and under-explored crystal chemistry that could contain many new structures and magnetic materials. Another common …

Integrated Techniques To Identify And Characterize Resistance To Fusarium Wilt Caused By Fusarium Oxysporum, F. Sp. Vasinfectum Race 4 In Two Domesticated Gossypium Species, Stephen Parris

All Dissertations

Fusarium wilt of cotton (Gossypium hirsutum and G. barbadense), caused by Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4), is the most threatening disease faced by today’s cotton breeders. During the past 20 years, over $7 million have been dedicated to efforts in breeding upland cotton for resistance to FOV4 while yielding little to no results. To counteract this, we conducted a study in Clint, TX, that utilized control plots and geostatistical methods to adjust phenotypic data for the heterogeneous distribution of FOV4 in the field, improving the accuracy of genetic resistance assessments. Concurrently, early-generation genetic mapping in …

Aspects Of Stochastic Geometric Mechanics In Molecular Biophysics, David Frost

All Dissertations

In confocal single-molecule FRET experiments, the joint distribution of FRET efficiency and donor lifetime distribution can reveal underlying molecular conformational dynamics via deviation from their theoretical Forster relationship. This shift is referred to as a dynamic shift. In this study, we investigate the influence of the free energy landscape in protein conformational dynamics on the dynamic shift by simulation of the associated continuum reaction coordinate Langevin dynamics, yielding a deeper understanding of the dynamic and structural information in the joint FRET efficiency and donor lifetime distribution. We develop novel Langevin models for the dye linker dynamics, including rotational dynamics, based …

An In Vitro Platform To Characterize Myocardial Wound Remodeling, Jonathan Heywood

All Dissertations

Heart Failure, sometimes called Congestive Heart Failure, is a collection of pathological disruptions in which the heart is unable to pump blood properly. It affects over 6 million people in the United States, with the cost-per-patient at approximately $30,000 and the total cost estimated to be $160 billion by 2030. There is no single cause of heart failure, as it can manifest as a varying array of diseases, disorders, and syndromes. However, many of these underlying diseases result specifically from dysregulation of mechanically active cells called cardiac fibroblasts, which play a critical role in the remodeling of the extracellular matrix …

Zero-Knowledge Reductions And Confidential Arithmetic, Marvin Jones

All Dissertations

The changes in computing paradigms to shift computations to third parties have resulted in the necessity of these computations to be provable. Zero-knowledge arguments are probabilistic arguments that are used to to verify computations without secret data being leaked to the verifying party.

In this dissertation, we study zero-knowledge arguments with specific focus on reductions. Our main contributions are:

1. Provide a thorough survey in a variety of zero-knowledge techniques and protocols.
2. Prove various results of reductions that can be used to study interactive protocols in terms of subroutines. Additionally, we identify an issue in the analogous definition of zero-knowledge for …

Cfrp Delamination Density Propagation Analysis By Magnetostriction Theory, Brandon Eugene Williams

All Dissertations

While Carbon Fiber Reinforced Polymers (CFRPs) have exceptional mechanical properties concerning their overall weight, their failure profile in demanding high-stress environments raises reliability concerns in structural applications. Two crucial limiting factors in CFRP reliability are low-strain material degradation and low fracture toughness. Due to CFRP’s low strain degradation characteristics, a wide variety of interlaminar damage can be sustained without any appreciable change to the physical structure itself. This damage suffered by the energy transfer from high- stress levels appears in the form of microporosity, crazes, microcracks, and delamination in the matrix material before any severe laminate damage is observed. This …