Digital Commons Network^™

Optimizing Photoacoustic Imaging With Advanced Reconstruction Techniques: Compressive Sensing And Deep Learning, Mary Anjaley Josy

Dissertations

Photoacoustic Tomography (PAT) is a noninvasive medical imaging technique that combines the advantages of optical imaging and ultrasonic detection, offering deep tissue visualization with high resolution. Despite its potential, the effectiveness of PAT is dependent on the accuracy and efficiency of the underlying imaging algorithms. This thesis aims to enhance the resolution and speed of PAT imaging through the integration of compressive sensing (CS) and deep learning techniques, targeting both full-view and limited-view sensor configurations. Two model-based CS iterative algorithms are developed: relaxed-basis pursuit via alternating direction method of multipliers (rBP-ADMM), and split Bregman total variation (SBTV) formulation. Additionally, Plug-and-Play …

Tackling Toxicity And Harassment In Online Environments Through The Use Of Artificial Intelligence, Heba Saleous

Dissertations

With the increase in popularity of online communities, such as social media platforms, online games, and chatroom servers, there is a need to improve chat and content moderation. Platforms have reported an increase in the prevalence of toxic behavior and hate speech. Meanwhile, moderators are reporting difficulties in keeping up with the amount of data to check as well and the type of content they are exposed to, which further harms their own mental health. The main objective of this work is to address the challenges that exist within online communities with the rising prevalence of hate speech. Additionally, some …

The United Arab Emirates Birth Cohort Study: A Pilot Examination Of Maternal And Infant Health Outcomes, Sharon Mutare

Dissertations

The first 1,000 days of life represent a critical window for influencing optimal fetal growth and establishing lifelong health foundations. Recent evidence underscores the significant association between maternal health and nutrition during this period and the subsequent risk of non-communicable diseases, which are responsible for 74% of global deaths. Despite the rapid globalization and urbanization experienced in the United Arab Emirates in recent years, there remains a paucity of research on how maternal health and nutrition impact perinatal outcomes among Emirati women.
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/="/">The primary objective of this dissertation was to profile the nutritional habits, status, and lifestyle of …

Trauma-Informed Teaching In Uae Schools: Investigating Teachers’ Experiences And The Effect Of A Cognitive Behavioral Intervention For Students Affected By Trauma, Hadeel Mohsen Saleh

Dissertations

This study explores UAE teachers’ experiences and knowledge regarding trauma-informed teaching and assesses the effectiveness of a cognitive-behavioral intervention for two elementary school students with Posttraumatic Stress Disorder (PTSD) in a general classroom setting. It also examines parents’ perceptions before and after the intervention. The study addresses two primary concerns: 1) the preparedness of UAE teachers to support trauma-affected students in schools, and 2) the efficacy of a targeted cognitive-behavioral intervention aimed at improving students' emotional regulation and behavioral outcomes. Using an exploratory sequential design, qualitative data from seven semi-structured interviews with UAE teachers revealed a significant gap in training …

Use Of Cement-Free Geopolymer Composites In Different Construction Applications, Joud Mohamad Hewalla

Dissertations

The demand for sustainable and eco-friendly construction materials has driven significant interest in the development of cement-free Geopolymer (GP) composites. A comprehensive scientometric analysis was conducted, highlighting a steady increase in research on geopolymer materials since 2013, with fire resistance, corrosion protection, and repair being the most studied applications. However, gaps remain in areas like 3D printing, heavy metals absorption, rehabilitation and repair, screed flooring, and shotcrete. The review emphasized the need for further investigation into lifecycle assessments and the potential use of diverse alumina- and silica-rich binders to enhance the environmental and mechanical properties of geopolymers. Accordingly, this thesis …

How Do Lgbt Employees Assess Their Firm’S Organizational Culture Regarding Lgbt Leadership?, Philippe Honore

Dissertations

This study explored Lesbian, Gay, Bisexual, and Trans (LGBT) employees’ perceptions and assessments of their firms’ organizational cultures and, in particular, the opportunities within the culture that can lead to upper management positions for those who identify as LGBT. The research sought to understand the extent to which inclusivity efforts are reflected in real career progression opportunities for openly LGBT employees working in San Diego County. Employing a convergent parallel mixed-methods research design, the study incorporated quantitative surveys and qualitative interviews to achieve a comprehensive understanding of participant’s perspectives and experiences. The decision to use both methods allowed the research …

Leveraging Social Practices In The 11th Grade American Literature Classroom: Video Games As Texts, Alora Moser

Dissertations

This quasi-experimental study explores the effectiveness of using a video game as a text in high school narrative instruction, testing Lave and Wenger’s (1991) situated learning theory, which posits that learning is a by-product of social interaction. This study seeks to bridge the gap between literacy practices at home and in school (Beavis, 2014; Ladson-Billings, 1995), effectively acknowledging students’ cultural capital, including multiliteracies (New London Group, 1996) and affinity spaces (Gee, 2013) in privileged academic settings such as the Georgia Milestones American Literature End of Course assessment. 11^th grade American literature students in a suburban Georgia high school were …

Bridging The Gap And Shaping Behavior: Applying Gilbert’S Behavioral Engineering Model To Explore The Role Of A Parent-Teacher Communication Tool On Parental Involvement, Christina Holtapp

Dissertations

This study investigated the environmental and behavioral factors influencing parent-teacher communication in a rural high school setting. The research used a mixed-methods approach, incorporating surveys and focus groups with parents and teachers, to explore using the mobile communication app ParentSquare. The findings reveal a generally positive perception of ParentSquare among parents, who appreciate its convenience, centralized communication features, and ability to connect with teachers. However, initial login difficulties and limited internet access in remote areas were also identified. The study also identifies a discrepancy between parents' perceived importance of involvement and their actual participation, suggesting a need for schools to …

Under The Surface Of Perfectionism: A Qualitative Examination Of Perfectionism In Women Leaders, Rachelle Martin

Dissertations

This qualitative study explores the manifestations and management of perfectionism among women leaders, framed through the lens of conservation of resources (COR) theory. By examining the experiences of women across various industries, the research highlights how perfectionism can act both as a strength and a challenge, depending on resource availability and self-awareness. The findings emphasize the compounded pressures faced by women, particularly women of color, and the significant role of self-awareness, coping mechanisms and mitigation techniques. Participants revealed how resource depletion may contribute to heightened perfectionistic tendencies, which subsequently may impact career outcomes. Self-awareness emerged as a moderating factor that, …

Fabrication And Evaluation Of Multicomponent Biomimetic Scaffolds For Bone Tissue Engineering, Mozan Osman Hassan

Dissertations

Bones have an inherent ability to remodel, but critical-size defects can hinder regeneration, leading to delayed healing or non-union fractures. Traditional bone grafts have limitations, such as donor site morbidity and immune rejection, driving the need for synthetic bone substitutes. Bone tissue engineering (BTE) addresses this by developing biomimetic scaffolds that replicate bone properties. This research aimed to fabricate composite scaffolds from strontium (Sr) and zinc (Zn) doped nano-hydroxyapatite (nHAp), collagen, and poly(lactide-co-glycolide) (PLGA). Different doping percentages of Sr/Zn (1%, 2.5%, 4%) were used to fabricate the scaffolds using supercritical CO2 (ScCO2) and electrospinning techniques. Scaffolds were then analyzed for …

A Delphi Study On The Use Of Simulation In Undergraduate Nursing Education, Diana L. Bailey

Dissertations

The lack of traditional clinical sites for nursing students has prompted a surge in simulation as an innovative teaching strategy in undergraduate nursing education. The International Nursing Association for Clinical Simulation and Learning (INASCL) developed the INACSL Standards of Best Practice: SimulationSM to direct schools of nursing in implementing high-quality simulations. As simulated experiences replace traditional clinical experiences, it is imperative that simulated experiences replicate real-life patient scenarios. The purpose of this Delphi study was to establish consensus on the use of the INACSL Standards of Best Practice: Simulation in undergraduate nursing education. The conceptual frameworks guiding this study were …

An Insider's Perspective To Mentoring Novice Math And Science Teachers In A University Mentoring Program: A Self-Study, Krishna R. Millsapp

Dissertations

Novice teachers benefit from individualized and cohort mentoring to help them successfully navigate student teaching and the first years of independent teaching. However, schools are experiencing a rise in attrition rates post-pandemic, especially in math and science. Mentoring, goal setting, and community-building are deemed important for retaining novices and providing them with individualized support as they navigate instructional challenges and professional responsibilities. This self-study investigates the experiences of a mentor while leading a new Professional Development & Mentoring Program for math and science novices. Educative mentoring and Hegarty’s Reflective framework helped guide the reflections of the mentor as mentoring strategies …

Warm Bodies, Strong Attachments, And The Search For Better Bonds: The Politics Of Human-Animal Entanglements In U.S. Fiction And Media, John Charles Hawkins

Dissertations

This dissertation describes human-animal relationships as sites of political longing and meaningful failure in the context of twentieth and twenty-first U.S. fiction and media. I locate three tendencies of imagination prevalent in writing about bonds between humans and other animals: collaboration in regional modernity, refamiliarization in consumer capitalism, and transformation in rationalist patriarchy. These expressions of desire for a different way of relating, I argue, open important windows into the places where current power structures generate suffering and distress. I also emphasize the compelling but imperfect nature of these expressions. The texts and images in this dissertation offer attempts to …

“I Really Like The Idea Of Being The Source Of Change”: The Perspectives Of Black And Latine Youth Experiencing Low Income About How Personal Change Occurs In Out-Of-School Group Programs, Kevin Miller

Dissertations

Structured out-of-school programs (OSPs) can be contexts in which youth can be producers of their own positive change (Eccles & Gootman, 2002). However, despite a considerable body of research documenting the benefits of participating in OSPs, there is a lack of knowledge about how youth of color in low-income communities define positive personal change in OSP settings. As a result, many OSPs and interventions designed for youth of color rely on adult practitioners’ or researchers’ perspectives of the change process, which may weaken program impact and fail to holistically meet youths’ developmental needs. This study uses a critical realist scientific …

Regulatory, Structural And Functional Studies Of The Adp-Glucose Pyrophosphorylase From Photosynthetic And Heterotrophic Organisms, Gabriela Martinez-Ramirez

Dissertations

The production of biofuels like ethanol has increased with the transition to renewable energy. Starch can be converted into ethanol through chemical modification. Increasing the availability of starch is crucial to fight back climate change thus, researchers have focused on the biotechnological modification of plants. This modification is known as transgenics, where a plant is modified by the insertion of genes, to make it as productive as possible. The genes inserted code for enzymes that control pathways responsible for the synthesis of certain biomolecules, in this case starch. The synthesis of starch in plants (as glycogen in both photosynthetic and …

Navigating Culture And Family In Post-Secondary Education As Nigerian American College Students, Funmilayo Ojikutu

Dissertations

The purpose of this dissertation is to examine how Nigerian Americans and their families understand academic success, identity, and family influence. This research study aims to understand these three areas by examining the experiences of five Nigerian American undergraduate students and their respective families. The data for this study was collected through individual interviews, focus groups, and an artifact analysis. Through using the Multidimensional Model of Racial Identity framework, findings demonstrated the importance of balancing identities, community, legacy, and shifts in generational mindsets. The findings in this dissertation offer larger discussions related to differences within the Nigerian community, the impact …

Investigating The Neurovascular Correlates Of Cognitive Function In Individuals With Spinal Cord Injury Using Functional Near-Infrared Spectroscopy, Donna Yali Chen

Dissertations

Individuals with spinal cord injury (SCI) have a 13 times greater risk of cognitive impairment than able-bodied individuals and commonly report symptoms of depression and anxiety. The reports of cognitive impairment in individuals with SCI are independent of concomitant brain injury. Although the direct cause of cognitive impairment in individuals with SCI is unknown, key contributors may include comorbid depression, chronic pain, anxiety, fatigue, brain injury, or cardiovascular dysfunction. Previous studies have focused on SCI at the level of the spinal cord but have under-investigated the supraspinal levels. Due to the lack of neuroimaging studies on SCI rehabilitation, it is …

A Micromagnetic Study Of Skyrmions In Thin-Film Multilayered Ferromagnetic Materials, Nicholas J. Dubicki

Dissertations

Magnetic skyrmions are topologically protected, localized, nanoscale spin textures in non-centrosymmetric thin ferromagnetic materials and heterostructures. At present they are of great interest to physicists for potential applications in information technology due to their particle-like properties and stability. In a system of multiple thin ferromagnetic layers, the stray field interaction was typically treated with various simplifications and approximations. It is shown that extensive analysis of the micromagnetic equations leads to an exact representation of the stray field interaction energy in the form of layer interaction kernels, a so-called 'finite thickness' representation. This formulation reveals the competition between perpendicular magnetic anisotropy …

Enhancing Community Flood Resilience By Incorporating Landscape Hydrological Sensitivity And Connectivity, Wenlong Feng

Dissertations

Rapid urban expansion and dramatic climate change have significantly increased the intensity and frequency of floods worldwide. With rising flood risks, conventional flood defense strategies that rely on structural measures become ineffective. The present designations for flood-prone areas, such as FEMA's flood maps, are becoming unreliable. Flood risk management is shifting toward enhancing community flood resilience, highlighting the importance of non-structural approaches. Landscape resilience has become a foundation of community flood resilience. However, past urban development typically undermined natural hydro-ecological functions and landscape resilience because of poor recognition of landscapes' ecological role, hydrological sensitivity, and hydrological connections. This study aims …

Certifying Stability In Runge-Kutta Schemes: Algebraic Conditions And Semidefinite Programming, Austin Juhl

Dissertations

Numerical stability is a critical property for a time-integration scheme. In the context of Runge-Kutta methods applied to stiff differential equations, A-stability is one of the most basic and practically important notions of stability. Dating back to the work of Dahlquist, it has been known that A-stability is equivalent to the Runge-Kutta stability function satisfying a particular convex feasibility problem. Specifically, up to a transformation, the stability function lies in the convex cone of positive functions. In recent years, sum-of-squares optimization and semidefinite programming have become valuable tools in developing rigorous certificates of stability in dynamical systems. Therefore, it is …

Federated Learning Systems For Mobile Sensing Data, Xiaopeng Jiang

Dissertations

Federated Learning (FL) has emerged as a new distributed Deep Learning (DL) paradigm that enables privacy-aware training and inference on mobile devices with help from the cloud. This dissertation presents a comprehensive exploration of FL with mobile sensing data, covering systems, applications, and optimizations.

First, a mobile-cloud FL system, FLSys, is designed to balance model performance with resource consumption, tolerate communication failures, and achieve scalability. In FLSys, different DL models with different FL aggregation methods can be trained and accessed concurrently by different apps. In addition, FLSys provides advanced privacy-preserving mechanisms and a common API for third-party app developers to …

Data Driven Decision Making For Sustainable Planning And Operations Of Large Scale Networks, Bahareh Kargar

Dissertations

This dissertation explores data-driven decision-making networks, focusing on sustainable planning and operations for large-scale systems such as healthcare supply chains and power systems. One significant application in healthcare is the optimization of vaccine supply chains. An agent-based simulation-optimization modeling framework is developed to enhance the efficiency and sustainability of vaccine distribution. First, an agent-based epidemiological model of COVID-19 is extended to capture disease transmission dynamics and forecast the number of susceptible individuals and infections. Then, a sustainable vaccine supply chain considering the impacts of greenhouse gases is developed and integrated with the simulation model to minimize total costs and environmental …

Electrified Membrane For Water Treatment And Resource Recovery: Advancing Multiscale Strategies In Gas-Involving Reactions, Jianan Gao

Dissertations

Multifunctional, modular, and scalable water treatment technologies that operate without chemical additives are crucial for addressing global water pollution challenges. While traditional membrane-based separation processes are crucial for ensuring clean water supplies, they primarily focus on pollutant removal rather than on the upcycling of pollutants into valuable resources. Electrified membrane filtration presents a robust alternative, utilizing minimal or no chemical additives and harnessing electrical power to directly reduce contaminants or produce reactive oxidants or reductants on-site.

This dissertation is dedicated to the development of innovative electrochemically reactive membranes designed to address three major challenges: (1) the engineering of electrocatalysts with …

A Methodological Framework For Ontology Development, Enrichment, And Application In Natural Language Processing Tasks, Navya Martin Kollapally

Dissertations

Electronic Health Records (EHRs) have been widely used in healthcare to record demographics, vital signs, test results, immunizations, medical imaging reports, differential diagnoses, etc. It is now accepted that non-clinical (e.g., social) factors have a substantial influence on health outcomes. Hence, it is desirable to record these Social and Commercial Determinants of Health (SDoH & CDoH) in an EHR. The "non-text parts" of EHR notes (e.g., data tables) rely on coded terms from underlying ontologies or terminologies to facilitate semantic interoperability. Ontologies help define concepts, the relationships between them, and instances that can be utilized in research.

The first accomplishment …

Microwave Catalysis-Enabled Membrane Processes For Microbial Inactivation, Fangzhou Liu

Dissertations

The COVID-19 pandemic has highlighted the urgent need for advanced technologies to combat virus transmission. Traditional membrane filtration technologies primarily serve as physical barriers, capturing pollutants but failing to inactivate microbial agents such as bacteria and viruses. These membranes typically target larger particles but are ineffective against sub-micrometer viral particles. Thus, there's a critical demand for membrane filtration processes that combine robust filtration with antifouling and reaction -enabled functions for efficient pathogen disinfection. This research explores a novel microwave-assisted membrane filtration process incorporating catalytic reactions to enhance microbial disinfection and prevent membrane fouling, offering a groundbreaking solution to global challenges …

Estimation Of Spo2 Levels And Heart Rate From Ppg Signals In The Presence Of Motion Artifacts, Chizhong Wang

Dissertations

In the rapidly advancing world of health technology, wearable devices are at the forefront, fundamentally changing how individuals monitor their health. The key to this transformation is photoplethysmography (PPG), a non-invasive optical method that measures blood flow variations through the skin by detecting changes in light absorption with each heartbeat. This capability makes PPG essential for monitoring vital signs such as heart rate and blood oxygen saturation(SpO₂). Furthermore, the utility of PPG signals has been extended beyond traditional health metrics to include human activity classification, offering a holistic perspective on an individual's physical health and activity levels, in …

Order-Picking Strategies And Efficiency Models For The Fulfillment Of Multi-Line E-Commerce Grocery Orders, Zijia Wang

Dissertations

The fulfillment process for Buy Online Pickup from Store grocery orders (BOPS-Grocery) is particularly challenging, given the large item count per order and the low-profit margins. This research investigates the BOPS-Grocery model and pursues the following objectives: (i) Defining and specifying the BOPS-Grocery fulfillment process. Differentiating the process from classical warehouse order picking., identifying performance objectives, and characterizing design options and facility layout. (ii) Modelling and developing order picking algorithms specific to the straight aisle section. Formulated as an order hatching problem with picker movement minimization. No order splitting, and (iii) modeling and developing order picking algorithms specific to the …

Numerical Techniques For Improving Simulations Of Tropical Cyclones, Yassine Tissaoui

Dissertations

The increasing frequency and intensity of tropical cyclones (TCs) due to climate change pose significant challenges for forecasting and mitigating their impacts. Despite advancements, accurately predicting TC rapid intensification (RI) remains a challenge. Large eddy simulation (LES) allows for explicitly resolving the large eddies involved in TC turbulence, thus providing an avenue for studying the mechanisms behind their intensification and RI. LES of a full tropical cyclone is very computationally expensive and its accuracy will depend on both explicit and implicit dissipation within an atmospheric model. This dissertation presents two novel numerical methodologies with the potential to improve the efficiency …

Collision Dynamics Of Compound Droplets In Microchannels: A Combined Numerical And Data-Driven Study, S M Abdullah Al Mamun

Dissertations

Understanding and predicting the hydrodynamic interactions of micron-scale droplets is crucial in a wide range of industrial and real-life applications, including microfluidics, pharmaceutics, drug delivery, food science, and enhanced oil recovery. These multi-phase and multi-scale phenomena are further complicated by the presence of core droplets of an immiscible fluid within shell droplets, known as compound droplets. The collisions and interactions of droplets in emulsions are influenced by various physical and geometric parameters, leading to distinct rheological and dynamic responses. This research employs numerical methods for a systematic parametric study of both simple and compound droplet pair collisions under confined shear …

Large Deviation Theory In Stochastic Processes: Applications To Biological Modeling, Moshe C. Silverstein

Dissertations

This dissertation delves into developing and applying stochastic models to analyze complex biological systems. It leverages Large Deviation Theory (LDT) to gain insights into these systems, focusing on two key examples: neural networks and calcium signaling dynamics. Traditional deterministic methods frequently fail to capture biological processes' randomness and inherent variability. Meanwhile, many stochastic approaches struggle to be mathematically tractable or provide accessible insights. The approach introduced in this study provides rigorous mathematical frameworks to enhance understanding of these stochastic behaviors while remaining tractable and insightful.

A stochastic model for a random biological neural network is constructed that addresses the dependencies …