Digital Commons Network^™

Advancing Unmanned Ground Vehicle Path Planning With Quantified Map Uncertainty, Israel Afriyie

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This thesis addresses the complex challenge of path planning for Unmanned Ground Vehicles (UGVs) in areas where traditional navigation systems are inadequate, such as unstructured or off-road military zones. Recognizing the limitations of current path planning algorithms, which primarily focus on optimizing for the shortest path and often fail to account for variability and risks, this research proposes an enhanced Hyperstar algorithm. This approach not only considers the fastest route but also integrates maximum delays and visibility risks into its computation, ensuring a balance between swift mission completion and concealment from adversaries.

Utilizing terrain maps and incorporating uncertainties in map …

Exploiting Physical Side-Channel Information For Offensive And Defensive Ends, Sisheng Liang

All Dissertations

Side-channel information consists of side effects of computation that range from microarchitectural to physical phenomena. Empirical studies have demonstrated the practical exploitability of these side effects in real-world systems for malicious attacks and effective defenses. In this dissertation, we discover, analyze, and exploit certain physical side-channel information for end-to-end attacks and defense across three studies.

In the first study, we demonstrate a new DNN model extraction attack named Clairvoyance that exploits certain far-field electromagnetic signals emitted from a GPU to steal DNN models several meters away from the victim machine, even with some physical obstacles in between. Using Clairvoyance, an …

Frameworks For The Techno-Economic Assessment Of Membrane-Based Bioprocessing Platforms, Juan Jose Romero Conde

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This dissertation describes developing and implementing computational frameworks for simulating and optimizing purification processes in the biopharmaceutical industry. The framework performs techno-economic analyses to establish value propositions for new process alternatives, especially membrane technologies. Initially, the focus is developing a framework capable of simulating monoclonal antibody (mAb) capture using membrane and resin media in multi-column chromatography (MCC) platforms for continuous manufacturing. Subsequently, the impact of capture MCC is compared against other intensification strategies in established mAb manufacturing facilities. Finally, the framework application expands to simulate the purification of adeno-associated virus (AAV) vectors for gene therapy.

Chapter 2 details the framework …

Offensive Content Detection In Online Social Platforms, Ebuka Okpala

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Online social platforms enable users to connect with large, diverse audiences and the ability for a message or content to flow from one user to another user, user to followers, followers to user, and followers to followers. Of course, the advantages of this are apparent, and the dangers are also clearly obvious. The user-generated content could be abusive, offensive, or hateful to other users, possibly leading to adverse health effects or offline harm. As more of society's public discourse and interaction move online and these platforms grow and increase their reach, it is inherently important to protect the safety of …

Large-Scale Hpc-Empowered Power Electronics Modeling And Simulation In Photovoltaic Applications, Liwei Wang

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The rising popularity of renewable energy sources requires advanced, efficient power electronic systems for energy conversion, grid integration, and system management, thereby raising expectations for power electronics in the energy industry. The complexity of modern power electronic systems requires comprehensive simulations and in-depth analysis to predict performance accurately, but this process is impeded by prolonged simulation times. The primary objective of this dissertation is to develop a high-fidelity, high-speed event-driven simulator to tackle challenges related to mass data processing, uncertainty evaluation, as well as modeling and simulation issues in assessing the reliability of power electronics in large-scale Photovoltaic (PV) systems. …

Investigating Institutional Support For A Minority Engineering Program At A Historically White Institution, Stephanie Damas

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Engineering programs at historically White institutions (HWIs) often perpetuate stereotypes and racism against Black students, impacting their experiences and opportunities in the field. Minority engineering programs (MEPs) provide support and resources to minority students in engineering, challenging stereotypes and fostering positive identity development. MEPs push back on cultural norms by rejecting the stereotypical narrative of what it means to be Black in engineering. Despite their significance, MEPs face challenges in garnering institutional support and recognition within engineering departments. It is imperative to understand what institutional support for MEPs looks like to mitigate barriers identified in the literature. To address these …

Voices From The Countryside: Unveiling The Stories Of Rural Teachers In Stem Education, Devan A. Jones

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This narrative study delves into the overlooked perspective of rural communities within the broader educational landscape, highlighting their unique and vital role in education. It primarily aims to gain insights from K-8 teachers working in multigrade, multi-curricular Sustained Deep Rurality (SDR) schools situated in the challenging terrain of the Northern Rocky Mountain area. Employing a methodology centered around episodic narrative interviews and small story analysis, the study uncovers the intricacies and challenges inherent in teaching under the extreme conditions of rural environments.

These SDR schools, situated in remote and isolated regions, serve as vital pillars in rural education, embodying qualities …

Ultra High-Performance Concrete As A High Friction Surface Treatment For Pavements And Bridges, Kyle Maeger

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High Friction Surface Treatment (HFST) is a proven technology to reduce crashes on roadways by increasing the coefficient of friction between vehicle tires and the pavement. However, it is an expensive solution due to the high cost of the two commonly used constituent materials, calcined bauxite aggregate and epoxy resin binders.

This study evaluated the abrasion resistance performance of four alternative HFST aggregates to calcined bauxite using Los Angeles Abrasion and Micro-Deval Abrasion tests, and studied the surface texture utilizing a high-resolution laser scanner and friction utilizing the British Pendulum Test.

This study also assessed the performance of non-proprietary Ultra …

Probabilistic Frames And Concepts From Optimal Transport, Dongwei Chen

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As the generalization of frames in the Euclidean space $\mathbb{R}^n$, a probabilistic frame is a probability measure on $\mathbb{R}^n$ that has a finite second moment and whose support spans $\mathbb{R}^n$. The p-Wasserstein distance with $p \geq 1$ from optimal transport is often used to compare probabilistic frames. It is particularly useful to compare frames of various cardinalities in the context of probabilistic frames. We show that the 2-Wasserstein distance appears naturally in the fundamental objects of frame theory and draws consequences leading to a geometric viewpoint of probabilistic frames.

We convert the classic lower bound estimates of 2-Wasserstein distance \cite{Gelbrich90, …

Time-Domain Line Protection In Presence Of Renewables, Prabin Adhikari

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Inverter based resources (IBRs) are crucial in integrating renewable energy sources into the power grid. However, their unique fault characteristics, significantly different from synchronous generators (SGs), present several challenges for existing line protection schemes at both transmission and distribution levels. These schemes, reliant on distance and directional relays designed in phasor domain, are not well-suited for IBRs. Most published literature addressing this problem concentrates on altering the control design of inverters. However, this approach faces practical limitations. Inverter controls, often proprietary, are not readily accessible to utilities, rendering the control-based solutions impractical for widespread implementation.

To address this challenge, this …

Fluid-Solid Coupled Analysis Of Biological Samples In A Flow Chamber Using Optical Coherence Tomography, Reece W. Fratus

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Forces from fluid flow on a tissue or cellular boundary can drive remodeling processes through mechanotransduction pathways. In most cases, the exact mechanisms are not understood, such as in marine biofilm development or vascular remodeling. To gain a better understanding of these interactions, the flow profile at a solid boundary and the mechanical changes of that solid can be coupled together to determine the impact of fluid flow on mechanical remodeling. To achieve this, optical coherence tomography (OCT) is used to image the fluid and solid simultaneously. Fluid seeded with particles can be imaged and run through a particle image …

Don't Waste Our Time: Key Transformative Structures For Fast Track Learning, Carlita S. King

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Following a massive wave of school closures during the COVID-19 pandemic, educators found the need to be hyper-critical of how they spend their instructional time with students. Almost all students are expected to return nearly a full grade-level behind and would likely have to learn to navigate a completely new school environment. As a result, many educators were overwhelmed to cover unprecedented amounts of instructional content in less time. High-intensity tutoring programs have been known to have the potential to help struggling students advance their skills and gain up to three additional months of learning within a few sessions. The …

Fundamental Study Of Nonlinear Electrophoresis, Joseph Armakan Bentor

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Classical electrophoretic theory describes the linear response of particles suspended in Newtonian fluids under weak electric fields. When the electric field exceeds this weak limit, a nonlinear response arises due to non-uniform surface conduction over the curved particles. This nonlinear behavior introduces dependencies on fluid and particle properties not considered in the classical theory, offering potential advantages for microfluidic particle manipulation. While this phenomenon has been extensively studied theoretically and numerically in Newtonian fluids, experimental investigations have been relatively limited.

Fluid rheology can significantly alter particle dynamics under applied electric fields. Rheological properties like shear-thinning and elasticity which are not …

Electrochemical Characteristics Of Bio-Derived And Silicon-Based Materials For Lithium Ion And Lithium Sulfur Batteries, Nawraj Sapkota

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The increasing demand for advanced batteries, driven by automotive and energy storage needs, emphasizes the need for improved energy density, longevity, and cost-effectiveness. While lithium-ion batteries (LIBs) offer high energy density, their traditional anode and cathode materials are reaching their limits. Innovations in battery chemistry, particularly using sulfur cathodes and silicon-based anodes, are crucial. Sulfur and silicon are attractive due to their abundance, environmental friendliness, and higher theoretical capacities. This research aims to enhance the electrochemical performance of lithium-sulfur batteries using three-dimensional architectures and solid-state electrolytes, and to improve silicon-based materials by modifying their surface architectures.

Chapter 1 reviews the …

Lab To Leadership: How Do Women College Stem Students’ Classroom Experiences Inform Their Leader Identity Development?, Meredith Mcdevitt

All Dissertations

This dissertation is an exploration of leader identity development and women in science, technology, engineering, and mathematics (STEM) college academic classrooms. While there continues to be research promoting diversity in STEM professions, women remain underrepresented in STEM disciplines, leadership positions, and for this specific study, the college academic classroom. This dissertation represents an opportunity for women in STEM college students to reflect on their experiences in STEM academic spaces and communities, while self-exploring factors that shape their leader identity development. The research utilized a basic qualitative research design to understand the participant’s authentic experiences within the academic environment. Conducting semi-structured …

Assessment Of Tce And Chiral Pcb Dechlorination Rate, Congener Diversity, And Enantioselectivity In Town Creek, Sc, Usa Sediment Microcosms, Catherine P. Sumner

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Polychlorinated biphenyls (PCBs) and trichloroethene (TCE) are ubiquitous contaminants and are recognized as persistent organic pollutants due to their extreme chemical stability. PCBs were manufactured by chlorinating biphenyls that created 209 congeners with various structures, of which 19 are chiral and can exist as a pair of stable atropisomers. PCBs have been known to cause developmental and neurological toxicity in humans and wildlife; they can act as endocrine disrupters, carcinogens, and teratogens. Sangamo Weston Inc. was an industrial plant located near Town Creek in Pickens Country, South Carolina, that manufactured capacitors and used Aroclors 1016 and 1254 as dialectic fluids …

Ensuring The Privacy Compliance Of Voice Personal Assistant Applications, Song Liao

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Voice Personal Assistants (VPA) such as Amazon Alexa and Google Assistant are quickly and seamlessly integrating into people’s daily lives. Meanwhile, the increased reliance on VPA services raises privacy concerns, such as the leakage of private conversations and sensitive information. Privacy policies play an important role in addressing users’ privacy concerns and developers are required to provide privacy policies to disclose their apps’ data practices. In addition, voice apps targeting users in European countries are required to comply with the GDPR (General Data Protection Regulation). However, little is known about whether these privacy policies are informative and trustworthy on emerging …

How School Leaders Can Increase Teacher Satisfaction In A Rural Fringe High School In South Carolina, William T. Dyer

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Unfilled teaching positions are rising in South Carolina, increasing year over year. To combat this problem of practice, I conducted an improvement science study to understand factors that impact teacher satisfaction levels aimed to raise teacher retention rates. The study aimed to allow teachers to identify areas that school administrators can target to positively affect teacher satisfaction levels. I created a change idea based on this teacher feedback to impact their retention decisions. As an educator, I have identified three major themes in this area. First, influence over their profession impacts teachers' decision to return to their position each year. …

Linear And Nonlinear Topology Optimization With Morphing Beam Networks, Andrew S. Montalbano

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Topology optimization (TO) is an engineering design discipline dedicated to optimizing material distribution within a given domain. In traditional gradient-based topology optimization, the solid domain is discretized into small volumetric elements. Using finite element analysis (FEA) of the structure, the gradient of the objective function with respect to the design variables (the pseudo densities) is computed, and these design variables are updated iteratively until convergence is achieved. Although gradient-based TO methods are well-established, sensitivity analyses of objective functions and constraints can be both mathematically complex and computationally intensive. The nonconvex nature of most TO problems often complicates efficient convergence. Furthermore, …

Hybrid Physics-Infused Machine Learning Framework For Fault Diagnostics And Prognostics In Cyber-Physical System Of Diesel Engine, Shubhendu Kumar Singh

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Fault diagnosis is required to ensure the safe operation of various equipment and enables real-time monitoring of associated components. As a result, the demand for new cognitive fault diagnosis algorithms is the need of the hour. Existing deep learning algorithms can detect, classify, and isolate faults. Still, most depend solely on data availability and do not incorporate the system's underlying physics into their prediction. Therefore, the results generated by these fault-detecting algorithms sometimes need to make more sense and deliver when tested in actual operating conditions.

Similar to diagnosis, the fault prognosis of diesel engines is paramount in numerous industries. …

Opportunities To Learn In Rural South Carolina Schools: Rurality, Place, And Passion, Grig Sawyer

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High school principals can change the status quo of the current iniquitous disparities in the education system between South Carolina’s rural high schools and their more populated and affluent suburban schools. Using a non-standard structure and the resources in their control, these school leaders can find solutions so schools can offer rural students advanced math and science programs. Yet, there is a paucity of studies examining how small rural school principals make advanced math and science courses available to their students, particularly in rural South Carolina. Thus, studies must examine how South Carolina school leaders successfully offer advanced math and …

Genomic Data Science Approaches For Understanding Human Diseases, Snehal Shah

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The intricate interplay of genetic predisposition, environmental influences, and lifestyle acts as the multifactorial landscape of diseases. Understanding this complexity presents a significant challenge. Molecular insights into disease mechanisms, particularly the interactions of DNA, RNA, and proteins with environmental and lifestyle factors, have revolutionized disease diagnosis, prognosis, and treatment. High-throughput technologies, such as next-generation sequencing, generate large amounts of molecular data, holding a wealth of knowledge. These datasets unveil the roles of genes and their interactions with various factors through analysis, shedding light on previously unknown molecular mechanisms underlying disease pathogenesis. Furthermore, they facilitate the discovery of biomarkers crucial for …

Essays On Retail Operations, Yao Chen

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This dissertation consists of three essays examining various aspects of retail operations. The first essay explores the strategic implementation of free in-store pickup services. Motivated by the rise of omni-channel strategies, it analytically models how a profit-maximizing retailer decides to adopt free ship-to-store services for online-exclusive products. The analysis reveals the effects on pricing, shipping fees, and customer behavior, as well as how these services attract foot traffic and boost in-store sales. Prescriptive models are provided to help retailers assess the potential value and customer response to ship-to-store services.

The second essay investigates the impact of negative environmental, social, and …

Using Improvement Science To Increase The Achievement Of Multilingual Learners, Jamie L. Mccarthy

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The population in the United States continues to become more diverse each year. Our education system is not designed to support students that do not have English as a first language. The population of multilingual learners are falling behind their English Proficient peers. Inadequate teacher training and program design are contributing factors as to why multilingual learners are not demonstrating an appropriate rate of academic growth each year. This improvement science study was designed to determine a method that would decrease the achievement gap between multilingual learners and English proficient student groups. The teachers and I studied different co-teaching models …

Preparing For Kindergarten: An In-Depth Look At The Lived Experiences Of Parents Preparing A Child For Kindergarten, Grace Bache-Wiig

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The purpose of this multi-modal phenomenological study was to examine the lived experiences of parents preparing their first child for kindergarten and to evaluate the sources of information used to inform these experiences. Eight parents of rising kindergarteners were sampled for interviewing from preschool and homeschool settings in North Carolina. Semi-structured interviews were conducted to explore participant experiences and participants identified sources of information to be gathered for content analysis. The interview transcripts were analyzed using van Manen’s approach to identify units of meaning. Four major themes emerged from this study: emotions about kindergarten readiness, an emphasis on social and …

Relating Elasticity And Other Multiplicative Properties Among Orders In Number Fields And Related Rings, Grant Moles

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This dissertation will explore factorization within orders in a number ring. By far the most well-understood of these orders are rings of algebraic integers. We will begin by examining how certain types of subrings may relate to the larger rings in which they are contained. We will then apply this knowledge, along with additional techniques, to determine how the elasticity in an order relates to the elasticity of the full ring of algebraic integers. Using many of the same strategies, we will develop a corresponding result in the rings of formal power series. Finally, we will explore a number of …

An Emergency Response System To Assist The Movement Of Vehicles During Emergency Operations In Urban Transportation Networks, Jamal Nahofti Kohneh

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Emergency responders need to arrive at the emergency scene as soon as possible, but operating vehicles under emergency conditions can pose a risk to both the responders and other road users, potentially resulting in crashes or delays in emergency operations. In this research, an emergency response system is proposed to assist emergency and non-emergency response vehicles (ERVs and non-ERVs) during emergency operations in a connected vehicle environment. This system collects the information from connected ERVs and non-ERVs, utilizes this information as inputs in the proposed models, and sends instruction messages back to vehicles. The proposed models provide the fastest ERV …

Do I Belong?, Audrey Gilden

All Dissertations

To measure students' Social-Emotional-Learning (SEL), Lowcountry School District (LSD) administers Panorama Education surveys to students, teachers, and staff twice a year. The mission of the surveys is to support educators in radically improving student outcomes with data. Students are given two surveys: 1) Student SEL Competency & Well-Being and 2) Student Supports & Environment. The first survey focuses on supportive relationships and self-management, while the second focuses on teacher-student relationships, sense of belonging, and school climate. Looking specifically at the Student Supports & Environment survey, two areas of concern are school climate and sense of belonging. School climate measures the …

Answering The Call: Harnessing Internal Boundary Spanning Infrastructure To Organize For Rural District Improvement, Cynthia Ward

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Despite the number of students and the growing diversity of the students served by rural districts, a lack of research exists on rural district systems to support the continuous improvement of schools. The lack of understanding around systems for rural district improvement stands to exacerbate long-standing inequities for rural communities. Using a three-article format and a qualitative case study approach, this dissertation contributes to what is understood about rural district systems for continuous improvement of schools. The first article examines how a rural district organized for the continuous improvement of its schools. The second article uses an improvement science approach …

Hardware-Oriented Protection And Acceleration For Machine Learning Application, Antian Wang

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The security of Machine Learning (ML) grows along with the development of high-performance models and expanding application scenarios. Numerous users are benefiting from the convenience brought by transformative ML applications. In the meantime, various attackers are trying to find vulnerabilities within ML deployment service models, thereby undermining the performance of ML and jeopardizing stakeholders’ interests. The dissertation focuses on the two aspects of secure ML applications: acceleration and protection. Homomorphic Encryption (HE) emerges as a widely recognized security primitive suitable for the cloud computing service model, where the computation can be performed over ciphertext without decryption. However, evaluations in the …