Digital Commons Network^™

Identifying Mobility Hub Suitability In The Mid-Sized United States Urban Area Using Weighted Overlay And Percentile Based Local Peak Analysis, Eric Asplund

Theses and Dissertations

IDENTIFYING MOBILITY HUB SUITABILITY IN THE MID-SIZED UNITED STATES URBAN AREA USING WEIGHTED OVERLAY AND PERCENTILE‑BASED LOCAL PEAK ANALYSIS

By Eric Asplund

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Urban and Regional Planning at Virginia Commonwealth University.

Virginia Commonwealth University, 2026.

Major Director: Dr. Ivan Suen, Ph. D., Associate Professor, Faculty of Urban and Regional Studies and Planning

Shared mobility hubs are increasingly posited in transportation planning as interventions supporting multimodality, sustainability, and equitable access, but guidance on evaluation of potential hub locations remains uneven, particularly in mid-sized United States cities where …

Environmental Monitoring In Shallow Lakes: Public Health Threats In Urban Waters, Kyleigh E. Johnson

Theses and Dissertations

Lakes are an integral part of urban and suburban communities, providing ecological, recreational, and public health benefits. Many of these lakes are located in densely populated areas and are subject to urban influences on water quality. Algal toxins and Escherichia coli are two common recreational concerns. Algal toxins come from harmful algal blooms that are influenced by nutrient availability and temperature, while bacteria are often introduced through run-off and animal waste. Sampling every 3-4 weeks from May-October 2025 allowed for the assessment of seasonal patterns and site-specific differences across nine lakes in the Richmond area. The highest bacterial concentrations appeared …

Mathematical Models With Clinical Applications For Improving Health Outcomes, Helen Harris

Theses and Dissertations

In clinical settings, patients are exposed to many risks and stressors that could result in adverse health outcomes. Here we present mathematical models that seek to address these risks. First, we present a Markov Chain model to investigate the effect of medication reconciliation (MR) completion on patient health outcomes in the intensive care unit. Using this model, we simulate the annual incidence of adverse drug events (ADEs) for three different ADE rates. Based on the simulated results, we conduct a cost-benefit analysis for various levels of compliance to determine the financial implications of increasing MR completion depending on the baseline …

Absolute Quantification And Identification Of Rna From Rna-Lipid Nanoparticles Using High Resolution Mass Spectrometry, Jason C. Funderburk

Theses and Dissertations

RNA therapeutics are a rising drug category with potential use for a range of conditions encompassing infectious diseases to therapies for cancer, diseases, and genetic disorders. RNA-lipid nanoparticles (RNA-LNPs) are the prominent delivery method for these therapeutics approved products include mRNA vaccines and polyneuropathy treatments. The emergency use authorizations and orphan drug status of current RNA-LNP drugs has allowed approval without finalization of the regulatory analytical procedures for quality monitoring. The objective of the study was to develop an LC-MS assay to simultaneously measure identity and concentration of two therapeutically relevant intact RNA constructs extracted from RNA-LNPs to enhance quality …

Re-Sense, Nneoma Njoku

Theses and Dissertations

Re-Sense examines artist’s books as perceptual tools capable of reshaping how readers encounter history, memory, and archival absence. Beginning with the idea that books teach us how to know and how to see, the text argues that conventional book structures often reinforce Western knowledge systems through overemphasis of linearity, coherence, and containment. In contrast, artist’s books' experimental structures support novel modes of knowing and relation to ourselves and the world of humans and non-humans. The author describes this process of exhuming perception from Western constraints as re-sensing.

Through re-sensing, the historical past becomes less like a fixed record and more …

A Framework For Digital Energy Modulation And Translation In Projectional X-Ray Imaging, Richard R. Wargo

Theses and Dissertations

In projectional X-ray imaging, acquisition energy fundamentally influences subject contrast, image noise, and radiation dose. While dual-energy techniques exploit spectral differences to optimize contrast and enable material separation, acquiring multiple images of the same anatomy often requires additional exposures and increased system complexity.

This dissertation presents a framework for digital energy modulation (DEM), in which computational models are trained to translate projection images between energy domains without requiring additional X-ray acquisitions. DEM is conceived as a generalizable strategy for controlled contrast modulation in projection imaging, with potential applications in image optimization, radiation therapy alignment, and dual-energy applications.

The framework was …

Proof Of Recovery: A Model To Enhance Data Integrity In Data Management Systems, Gustaf Barkstrom

Theses and Dissertations

Businesses lose millions of dollars every year when they can’t restore data from backups. Research shows that Disaster Recovery Plan (DRP) testing is not conducted frequently enough, nor are records maintained that demonstrate full data recovery from backups. This work introduces a design science artifact called PRTOK that aims to increase DRP testing. The design science artifact is a software solution that integrates with Data Management Systems (DMS)

such as iRODS and DSpace, and can work with formats such as HDF5 and BagIt. Proof-of- recovery records, or tokens, are recorded in a replicated, resilient, and indelible proof-of- authority blockchain data …

Follow The Cyclists: Everyday Navigation Of Richmond's Bike Infrastructure, Emily E. Schreer

Theses and Dissertations

This thesis explores the embodied experience of cycling in Richmond, emphasizing the importance of centering firsthand, lived experience in cycling research and urban planning. While traditional transportation planning can often myopically prioritize efficiency and safety metrics to evaluate infrastructure, this project argues that such approaches overlook essential experiential, sensory, and emotional dimensions of cycling that determine how infrastructure is perceived, used, and ultimately succeeds or fails.

Through an ethnographic approach combining field observation of cyclist behavior and mental mapping sessions with Richmond cyclists, this study positions people who bike in Richmond as expert knowledge holders. Participant contributions, combined with observations …

Nanomagnet Based Straintronic Devices For Unconventional Computing: Simulation And Performance Analysis, Rahnuma Rahman

Theses and Dissertations

Nanomagnetic devices are of great interest in digital hardware because of their non-volatility and dynamic ability to change magnetization but suffer from high switching error rates and temperature sensitivity. Magnetostrictive nanomagnets that utilize strain to switch between stable magnetization states encoding bit information are of interest since they are extremely energy efficient as piezoelectric layers can be used to rotate magnetization that have switching energies in the range of attojoules. Their stochasticity can also be useful in probabilistic, analog, neuromorphic, and collective computing systems, where occasional switching errors are not devastating. The dissertation extends spintronics beyond conventional computing schemes by …

Fused Filament Fabrication Additive Manufacturing Of 17-4 Ph Stainless Steel: Process–Structure–Property Relationships In Magnetic Materials, Maanav Patel

Theses and Dissertations

Additive manufacturing (AM) enables the fabrication of complex metallic components through layer-by-layer processing directly from digital models. Among AM techniques, material extrusion–based processes such as fused filament fabrication (FFF) provide an accessible method for producing metal parts using filament feedstocks composed of metal powders and polymer binders. When applied to precipitation-hardening stainless steels such as 17-4 PH, the processing route and heat treatments can influence the resulting microstructure and functional properties. This work investigates the magnetic behavior of 17-4 PH stainless steel fabricated using FFF and evaluates how heat treatment conditions influence measured magnetic properties. Samples were produced and analyzed …

Exploring, Understanding, And Supporting Academic Help-Seeking In Context, Molly L. Taylor

Theses and Dissertations

Conceptualized as a self-regulated learning (SRL) strategy, academic help-seeking is a fascinating behavior because it is self-directed while also reliant on social interactions with help-givers (Karabenick, 2004). What is known about help-seeking in academic settings largely revolves around individual traits, strategies, motivations, beliefs, and identities, and how each of these constructs influence help-seeking outcomes (Bornschlegl et al., 2020; Fong et al., 2023; Karabenick & Gonida, 2018). What is underexplored in these areas, however, is how features of the learning context interact with student-level factors to shape academic help-seeking behaviors and beliefs. This dissertation attempts to address some of these gaps …

The Effects Of Overwash On Barrier Island Evolution And Building A Barrier Island Measure Of Resistance, Beth Thomas

Theses and Dissertations

Barrier islands are critical for coastal communities, as they serve as a natural buffer against storm surge, waves, and the effects of rising sea levels, protecting life and property. These islands continuously evolve due to both normal and severe environmental conditions; global warming makes it increasingly difficult to predict the evolution of these islands due to increases in storm frequency and intensity. We present a cellular model of barrier island evolution consisting of biotic and abiotic processes including the effects of vegetation, wind, ocean currents, and gravity. The model is used to predict the future evolution of barrier islands off …

Machine Learning-Based Spatio-Temporal Modeling Of Climate Dynamics And Desertification In The Sahara–Sahel Region, Stephen M. Tivenan

Theses and Dissertations

Arid climate classifications are threshold-dependent and easily interpretable mappings that are widely used in ecological, agricultural, and climate-related studies. These classifications inform scientific understanding, support policy and land management decisions, and provide an intuitive summary of environmental conditions. Despite their usefulness, traditional arid climate classifications often fail to quantify uncertainty, incorporate spatial context, or account for complex relationships among relevant environmental variables. Existing approaches to uncertainty assessment have largely relied on comparing classifications across multiple datasets or alternative formulas, but these methods generally overlook important spatial dependence and latent structure in the data.

This dissertation develops three machine learning-based statistical …

In-Between Echoes, Jiayi Liang

Theses and Dissertations

In this dissertation, I explore memory, diaspora, labor, and intergenerational trauma through constructed photography and experimental film. Informed by Homi K. Bhabha’s concept of the Third Space, I examine how identity is shaped through displacement, cultural negotiation, and inherited memory. Drawing from my relationship with my grandmother and my experience as a Chinese woman living in diaspora, I consider labor as both survival and care, tracing how domestic gestures and emotional structures continue across generations. Through collage, reconstruction, and animation, I rework fragments of family archives, colonial landscape imagery, and personal photographs to address grief, racialized perception, belonging, and the …

An Examination Of The Determinants Of Audit Quality: Implications From Firms Listed In Us Stock Markets, Abdelrahman Naser Elmaria

Theses and Dissertations

The purpose of this thesis is to examine the effect of several audit determinants, namely audit tenure, non-audit to audit fees ratio, auditing firm size, and firm size, impact on audit quality. This thesis extends the existing literature on audit determinants effect on audit quality using a Generalized Linear Model, (GLM) regression with robust estimation by analyzing a sample of 446 companies from the USA in the manufacture and service sectors. This is conducted through a series of diagnostic tests to identify an appropriate regression model. Such tests include testing and checking of baseline regression models to check for multicollinearity, …

Dimension Reduction Involving Exogenous Variables With Applications In Manufacturing And Healthcare, Linxi Li

Theses and Dissertations

High-dimensional data analysis presents diverse challenges, including the curse of dimensionality, the complexities of working with datasets that combine large feature spaces with limited sample sizes, and difficulties in identifying meaningful relationships among variables. As datasets grow in size and complexity across different fields, it is increasingly important to develop practical approaches for extracting essential information from such data. Dimension reduction methods address these challenges by alleviating the effects of high dimensionality, enhancing the ability to reveal hidden patterns, and uncovering latent structures within the data to support further analysis. Some methods reduce dimensionality while preserving all relevant information, offering …

Medical Linear Accelerator Water Tank Measurements Optimization For Commissioning, Tyler R. Laugh

Theses and Dissertations

Beam commissioning is a critical component of linear accelerator (LINAC) implementation, requiring accurate measurement of percent depth dose (PDD), beam profiles, and output factors across a wide range of field sizes. Conventional commissioning workflows often require multiple detectors and can be time-intensive, particularly for small-field dosimetry where measurement accuracy is highly sensitive to detector characteristics. This study evaluated the performance of a plastic scintillation detector (BP-PSD) for full water tank commissioning and its potential to improve efficiency while maintaining dosimetric accuracy.

Beam data were acquired for field sizes ranging from 1 × 1 cm² to 40 × 40 cm² using …

Towards Sample-Efficient Deep Reinforcement Learning, Guang Yang

Theses and Dissertations

Deep reinforcement learning (DRL), combining reinforcement learning and high-performance function approximations such as deep neural networks (DNN), is a powerful approach to solving complex sequential decision-making problems. However, due to the complex solution space of the sequential decision-making problems and the inefficient design of the DRL algorithms, DRL algorithms usually require a prohibitively large number of data samples to train effective strategies. Consequently, it is difficult to apply these DRL algorithms to complex real-world problems that require high costs to collect a large volume of data samples. This dissertation proposes new mechanisms to address this sample inefficiency issue, realizing sample-efficient …

An Integrated Data-Driven Framework For Arctic Shipping: Analyzing Vessel Speed, Environmental And Ecological Factors Through Innovative Statistical Spatio-Temporal Methods, Inverse Optimization And Machine Learning, Mauli Pant

Theses and Dissertations

This dissertation develops an integrated data-driven framework to analyze vessel navigation and ecological risk in the United States Arctic from 2010 to 2019. As environmental change and maritime activity increase in the region, understanding how vessels respond to dynamic conditions and how those responses interact with marine ecosystems has become increasingly important. A central theme of this dissertation is the treatment of vessel speed as both an observed outcome and a decision variable reflecting trade- offs among operational, environmental, and ecological factors. The first chapter develops a predictive framework for vessel speed over ground (SOG) using Gaussian Process Boosting (GPBoost), …

Student Centered Approaches To Analyzing Engagement And Discourse, Kamil Hankour

Theses and Dissertations

Student engagement and participation in classroom discourse are widely recognized as powerful predictors of meaningful science learning, yet students’ own perspectives on the factors that shape their engagement and participation are currently underexamined. Prior research has established strong links between engagement, discourse and outcomes such as academic achievement (Bae & DeBusk-Lane, 2019; Fredricks et al., 2004; Sedova et al., 2019), but less is known about how students understand and interpret their experiences across individual, group-level and classroom contexts, particularly within historically marginalized populations (Cook-Sather, 2013; Schaefer et al., 2024). This three paper dissertation advances a line of inquiry integrating a …

Light And Unseen, Daša Kulikova

Theses and Dissertations

This thesis is a body of paintings and two poetic fragments. Shaped by distance and displacement, the work finds its ground in the tension between the desire to be free from the past and heal, and longing for home and connection. Painting practice becomes an event of contact with what is lost, or unclear, or in the process of becoming through accumulating layers, marks, erasures, and traces of the process of its making.

There Is A Puddle In Stonehenge, Nathaniel Newcomb

Theses and Dissertations

I began by making what I called "furniture": finding discarded logs and using a chainsaw, I milled out slabs of wood far larger than any normal board or beam, and gave them the function of chair, table, shelf. Sometimes it was a "shelf" in name only, and was commentary on furniture. In my practice, using discarded wood is necessary for the sake of the earth; making original pieces is necessary for the sake of my soul. I am reminded of megaliths when I erect these enormous forms in wood. I make intuitively, and like the meaning of megaliths, obscured by …

Plumbed 3-Manifolds And Neumann Moves, Noah J. Pope

Theses and Dissertations

We give a constructive proof that every weakly negative definite plumbing tree can be transformed into a negative definite one by a finite sequence of Neumann moves. The argument combines Neumann’s plumbing calculus with the diagonalization algorithm of Duchon, Eisenbud, and Neumann, which extracts the eigenvalues of the framing matrix directly from the combinatorics of the tree. We show that any positive eigenvalues are supported on linear branches and can be eliminated systematically via controlled applications of Neumann moves. This provides an explicit algorithm reducing weakly negative definite plumbing trees to negative definite ones.

Comorbid Psychosis In The General Population, Mariam Sankoh

Theses and Dissertations

Psychosis is a complex psychiatric phenotype characterized by substantial heterogeneity in symptom presentation, psychosis diagnosis, comorbidity patterns, and genetic architecture across diverse populations in the general population. Despite advances in psychiatric epidemiology and genomics, important gaps remain in understanding how psychosis symptoms and psychosis-related diagnoses manifest across racial and ethnic groups and how evolutionary genomic factors may contribute to disease risk and cross-ancestry genetic prediction. This dissertation, Characterizing Comorbidity in Psychosis in the General Population, integrates epidemiological, psychometric, and evolutionary genetic approaches to examine psychosis across diverse populations.

Aim 1 examined racial and ethnic differences in psychosis comorbidity patterns …

24-H Circadian Rest-Activity Rhythms And Physical Frailty In Older Adults: A Biopsychosocial Perspective On Sex Differences And Social Capital, Jisu Kim

Theses and Dissertations

Physical frailty is a prevalent geriatric syndrome characterized by age-related decline across multiple physiological systems. Physical frailty is associated with an elevated risk of adverse health outcomes, including chronic disease progression and all-cause mortality, representing a significant and growing public health concern. Disrupted circadian rest-activity rhythms (RARs) are increasingly recognized as clinically meaningful markers of physical frailty in older adults. However, the extent to which biological sex and social determinants of health (SDoH), particularly social capital, contribute to or modify the associations between RARs and physical frailty remains underexplored.

Therefore, this dissertation summarizes the existing literature on age-related changes in …

Mediator: Ornament As A Visual Language Of The Transcendent, Selma Fejzullaj

Theses and Dissertations

Adolf Loos’s declaration that “ornament is a crime” defined modernist design, establishing a legacy that dismisses ornamentation as wasteful and regressive. This research questions that legacy by repositioning aesthetics as a divinely grounded value, inspired by the Qur’anic vision of Paradise. In this celestial realm, beauty is not wasteful but a manifestation of divine perfection. Conceptually, the project reclaims ornament as a vital tool for contemplating metaphysical themes. Materially, it reimagines glass, shifting it from modernist "radical honesty" to a medium of layered depth. Recombining traditional Islamic ornamentation practices such as Girih and Chaharbagh, the project evokes the Qur’anic vision …

Centering Individual Well-Being In Learning Environments: Academic Stress, Psychological Safety, And Digital Discourse, Rachel Niemira Namboodri

Theses and Dissertations

Statement of Problem

How do we guide students through school while supporting their emotional and psychological health? This question lies at the heart of contemporary educational psychology research, as growing evidence demonstrates that students’ academic achievement and psychological well-being are deeply intertwined with their experiences in learning environments (Baumeister & Leary, 1995; Edmondson & Lei, 2014; Gopalan & Brady, 2020; Song et al., 2024; Spencer, 1995; Walton & Cohen, 2011). Decades of scholarship affirm that students’ academic achievement and psychological well-being are deeply intertwined with how they experience schools, classrooms, peers, teachers, and institutional structures (Baumeister & Leary, 1995; Edmondson …

A Mathematical Frameworks For Singular, Nonlinear Phenomena: Applications To Nematocyst Firing And Inhomogeneous Nls With Coulomb Potential, Abdulrahman Alharbi

Theses and Dissertations

Nematocysts are specialized cellular organelles found in all cnidarians, including corals and jellyfish, as well as in some single-celled protists such as dinoflagellates. These organelles display remarkable diversity in morphology and function, playing roles in prey capture and defense. The firing of a nematocyst is one of the fastest accelerations in nature, yet the underlying physical mechanisms remain not fully understood. In this work, we address key questions: how sufficient force is generated to overcome the fluid boundary layer, whether fluid–structure interaction models can reproduce observed dynamics, and what mechanisms trigger discharge.

Our research investigates models based on osmotic pressure …

Early Math Readiness And Later Achievement: A Longitudinal Study, Bailey Bontrager

Theses and Dissertations

The current body of literature provides much evidence that mathematics skills at the start of kindergarten are predictive of later mathematics achievement, and that students enrolled in early childhood education (ECE) programs are better prepared for mathematics at the start of kindergarten. However, the potential for children to develop mathematical skills prior to entering kindergarten relies on access to ECE programs and resources in families’ surrounding communities. Recent use of geospatial data collection techniques and measures of community resource availability have enabled researchers to examine specific localities for the ways in which community organizations and institutions support residents in particular …

De Novo Protein Binding To Zinc Oxide Through Biomineralization Pathways, Jean-Mark A. Francis

Theses and Dissertations

De novo proteins are structurally distinct from proteins found in nature and thus capable of having their amino acid sequence modified to accomplish tasks such as increasing protein-nanoparticle binding without unfolding or decomposing. Zinc Oxide nanoparticles are functionally distinct from their bulk counterparts and are widely used as semiconductors in a variety of fields such as medicine and agriculture. With demand for these nanoparticles increasing, environmentally sustainable methods of Zinc Oxide nanoparticle synthesis are being investigated as an eco-friendly alternative to currently utilized but environmentally hazardous chemical and physical techniques. This research investigates the binding characteristics between Zinc Oxide nanoparticles …