Physical Sciences and Mathematics Commons^™

Intelligent Software Tooling For Improving Software Development, Nathan Allen Cooper

Dissertations, Theses, and Masters Projects

Software has eaten the world with many of the necessities and quality of life services people use requiring software. Therefore, tools that improve the software development experience can have a significant impact on the world such as generating code and test cases, detecting bugs, question and answering, etc. The success of Deep Learning (DL) over the past decade has shown huge advancements in automation across many domains, including Software Development processes. One of the main reasons behind this success is the availability of large datasets such as open-source code available through GitHub or image datasets of mobile Graphical User Interfaces …

Appearance Driven Reflectance Modeling, James Christopher Bieron

Dissertations, Theses, and Masters Projects

Creating realistic computer generated imagery is essential for modern movies and video games. Recreating the appearance of materials is integral to generating such photo-realistic images. While the problem of how to model materials is well studied, here we will focus on the question of how to recreate the appearance of specific materials found in the real world. In this dissertation we will begin with a short introduction to rendering, followed by a discussion of various material models, techniques for measuring reflectance, and strategies for fitting these models to reflectance data. We will then introduce a novel two-stage process for fitting, …

Program Analysis For Software Engineers And Students, Jialiang Tan

Dissertations, Theses, and Masters Projects

Software inefficiencies are inevitable in computer systems. At the code level, software packages have become increasingly complex, they are comprised of a large amount of source code, sophisticated control and data flow, and growing levels of abstraction. This complexity often introduces inefficiencies across software stacks, leading to performance degradation. At the resource level, the evolution of hardware outpaces the performance optimization of software, leading to resource wastage and energy dissipation in emerging architecture. To better understand program behaviors, software developers take advantage of performance profiling tools. Existing profiling techniques, whether fine-grained profilers or coarse-grained profilers focus on identifying hotspots, which …

Characterizing Molecular Environments In Acrylic Paint Via Single-Sided Nmr, Lyndi Kiple

Dissertations, Theses, and Masters Projects

Acrylic paint is a modern artistic material made of colored pigment and polymeric binder. Acrylic binder requires fundamental study at the molecular level to understand its physical properties for purposes of art conservation and general polymer chemistry. The research presented in this thesis uses single-sided nuclear magnetic resonance (NMR) as a non-invasive and non-destructive way to measure relaxation and self-diffusion, which provide insight to molecular mobility and physical properties of proton-containing samples. Specifically, this study relies on T2 relaxation to gain insight to regions within acrylic paint with different molecular mobilities. In both dry and wet paint, relaxometry data revealed …

Biotic And Abiotic Factors Associated With Temporal And Spatial Variability Of Constitutive Mixotroph Abundance And Proportion, Marcella Dobbertin Da Costa

Dissertations, Theses, and Masters Projects

Mixotrophic protists, which combine the use of photosynthesis and prey ingestion to obtain nutrients for growth, comprise a substantial portion of the plankton community. However, there is a major gap in our understanding of how mixotroph prevalence varies spatially and temporally and under what conditions they dominate. I utilized a recently developed molecular technique to experimentally identify active mixotrophs (taxa identified to be grazing when samples were collected) and combined this with microscopy data to estimate active mixotroph abundance and proportion at two locations in a temperate estuary over a year. Active mixotroph abundance was compared to potential mixotroph (taxa …

Learning-Based Ubiquitous Sensing For Solving Real-World Problems, Woosub Jung

Dissertations, Theses, and Masters Projects

Recently, as the Internet of Things (IoT) technology has become smaller and cheaper, ubiquitous sensing ability within these devices has become increasingly accessible. Learning methods have also become more complex in the field of computer science ac- cordingly. However, there remains a gap between these learning approaches and many problems in other disciplinary fields. In this dissertation, I investigate four different learning-based studies via ubiquitous sensing for solving real-world problems, such as in IoT security, athletics, and healthcare. First, I designed an online intrusion detection system for IoT devices via power auditing. To realize the real-time system, I created a …

Climate Impacts On Spatiotemporal Habitat Usage Of Mid-Atlantic Fishes, Adena Jade Schonfeld

Dissertations, Theses, and Masters Projects

Climate change has altered marine environments, most notably by increasing water temperatures and reducing dissolved oxygen concentrations. These persistent changes have impacted the phenology and spatiotemporal habitat usage of mobile species, often through distributional shifts poleward or to deeper water. Climate-driven distributional shifts have been documented for numerous species inhabiting the Atlantic Ocean along the US East Coast, a region disproportionately affected by climate change. Adjacent estuaries are experiencing similar alterations to their physical environments and biotic community composition. Many estuarine species are seasonal residents and changes to environmental conditions within an estuary can result in altered usage and residence …

Development Of 3d And 360 Gis-Based Models To Visualize Projected Sea Level Rise In Coastal Virginia, Candice M. Vinson

Dissertations, Theses, and Masters Projects

Science communication is a skill that can be strengthened with practice. Like any skill, it helps to know what you need to practice in order to get better at it. When presenting information to an audience, the skill of science communication comes into play as early as the first draft of a presentation. As you think about how you will tell your story to the audience, you likely consider including text on slides, images, graphs, maps, or even videos. However, it is crucial to remember that accessibility barriers are something we must often consciously work to rid our presentations of, …

Achieving Real-Time Dnn Execution On Mobile Devices With Compiler Optimizations, Wei Niu

Dissertations, Theses, and Masters Projects

Deep learning, particularly deep neural networks (DNNs), has led to significant advancements in various fields, such as autonomous driving, natural language processing, extended reality (XR), and view synthesis. Mobile and edge devices, with their efficient and specialized processors and suitability for real-time scenarios, have become the primary carriers for these emerging applications. The advancements in AutoML tools (e.g., Network Architecture Search) and training techniques have resulted in increasingly complex and deep DNN architectures with larger computational requirements. However, achieving real-time DNN execution (inference) on mobile devices is a challenging task due to the limited computing and storage resources available on …

Matfusion: A Generative Diffusion Model For Svbrdf Capture, Samuel Lee Sartor

Dissertations, Theses, and Masters Projects

We formulate SVBRDF estimation from photographs as a diffusion task. To model the distribution of spatially varying materials, we first train a novel unconditional SVBRDF diffusion backbone model on a large set of 312,165 synthetic spatially varying material exemplars. This SVBRDF diffusion backbone model, named MatFusion, can then serve as a basis for refining a conditional diffusion model to estimate the material properties from a photograph under controlled or uncontrolled lighting. Our backbone MatFusion model is trained using only a loss on the reflectance properties, and therefore refinement can be paired with more expensive rendering methods without the need for …

Synthesis And Characterization Of Two Sets Of Group 12 Complexes With Organic Ligands, Michelle Sturner

Dissertations, Theses, and Masters Projects

The complexes of group 12 elements are subjects of incredible interest due to differences in their bioactivity. Zinc is an essential element of life and is required for many bodily processes including gene production, growth, and the immune response. Cadmium and mercury are both toxic elements to humans. Part of their activity is due to their ability to replace zinc metal centers. Synthesis of new group 12 complexes can provide insight regarding their bioactivity and how replacement of metal centers can affect the structure of enzymes. In this thesis, the preparation and characterization of two sets of group 12 complexes …

Subsurface Structure And Impacts Of Marine Heatwaves In The Chesapeake Bay, Nathan P. Shunk

Dissertations, Theses, and Masters Projects

Extreme temperature events known as Marine Heatwaves (MHW), akin to atmospheric heatwaves, have only recently received attention by the estuarine scientific community. Thus far, studies have focused solely on surface events due to scarcity of long-term subsurface data. This study investigates, for the first time, the subsurface temperature and dissolved oxygen (DO) anomalies associated with surface MHW events in a large, temperate, partially mixed estuary: the Chesapeake Bay (CB). Using over three decades (1986-2021) of in-situ data from several long-term monitoring programs in the CB (including sub daily moored measurements and monthly/bimonthly cruises along the main stem) and a global …

Achieving Equitable Offshore Wind Development: Lessons From European Stakeholders, Kacey Hirshfeld

Dissertations, Theses, and Masters Projects

The Biden Administration has set aggressive offshore wind energy goals, aiming to have 30 gigawatts of offshore energy in place by 2030. This amount of energy has the potential to power 10 million homes (White House, 2022), helping the administration to reach larger clean energy goals. In Virginia, Dominion Energy aims to have 2.6 gigawatts of offshore wind energy by 2026, enough to power up to 660,000 homes (Dominion Energy).

While the upcoming offshore wind energy development will create clean energy and green jobs, the ocean is no longer an open field for development and already supports a complex matrix …

Exploring Pah Partitioning In Oysters Using Immunological Techniques, Kristen Madison Prossner

Dissertations, Theses, and Masters Projects

Anthropogenic activities such as oil spills are major sources of polycyclic aromatic hydrocarbon (PAH) pollution in the environment. Bivalves such as C. virginica can accumulate high levels of PAHs in tissue due to a limited metabolic capacity for these compounds. Accordingly, bivalves have served as key biomonitoring species for contaminants and exposure to PAH through seafood consumption can also be an important risk to human health due to the toxic and carcinogenic potential of these compounds. For evaluating bivalve PAH levels, conventional analyses are limited due to extensive time and expense and unreliability. This work demonstrates the application of immunological …

Identifying Factors Controlling Dinophysis Spp. Feeding, Growth, And Toxin Production Through Field And Lab Studies, Vanessa R. Strohm

Dissertations, Theses, and Masters Projects

Harmful algal blooms (HABs) and their associated phycotoxins pose a threat to both human and shellfish health around the world. Dinophysis spp., a causative organism of diarrhetic shellfish poisoning (DSP) in humans, and its two toxin classes: dinophysistoxins (DTXs) and pectenotoxins (PTXs), have been documented throughout the year in the Chesapeake Bay. While DTX concentrations currently remain below regulatory limits in regional seafood products, further research is needed to understand environmental drivers, both biotic and abiotic, that may be impacting Dinophysis spp. feeding on prey, growth, and toxin production. To characterize populations of Dinophysis in situ, an Imaging FlowCytobot (IFCB) …

Spectroscopy And Dynamics Of Atmospherically And Combustion-Relevant Collision Complexes, John Patrick Davis

Dissertations, Theses, and Masters Projects

Potential energy surfaces describing bimolecular collisions sensitively depend on the chemical functionality and the relative orientation of colliding partners, thus defining the accessibly reactive and nonreactive pathways. Herein, we investigate the peculiar product outcomes arising from Jahn-Teller distortion of the nitric oxide and methane complex (NO-CH4). We have reported an in-depth spectroscopic and dynamics study of NO-CH4 by utilizing conformation-specific and action spectroscopy, as well as velocity map imaging, to understand the fundamental dissociative mechanisms at play. Ultimately, we have gained information about how the Jahn Teller effect possibly impacts the potential product energy transfer pathways. There is a translationally …

Constraining Of The Minerνa Medium Energy Neutrino Flux Using Neutrino-Electron Scattering, Luis Zazueta

Dissertations, Theses, and Masters Projects

Long baseline neutrino oscillation experiments rely on the flux from accelerator-based neutrino beams. As experimental neutrino physics moves to the next generation of experiments a precise characterization of the neutrino flux on a given experiment becomes crucial to the goals of the experiments: to precisely determine the neutrino oscillation parameters.This work takes advantage of neutrino-electron scattering processes for their precisely predicted cross section. The observed number of scattering events can be used as a benchmark to constrain the neutrino flux. A measurement was made of the energy spectrum of neutrino-electron elastic scattering (νe-→νe-), using data from the antineutrino-enhanced run period …

Emerging Red Sore Disease Of American Eel (Anguilla Rostrata) In Chesapeake Bay: Etiology, Epidemiology, And Impacts In Aquaculture And The Wild, Amanpreet Kaur Kohli

Dissertations, Theses, and Masters Projects

Emerging infectious diseases in aquatic systems, both in aquaculture and in the wild, are a global concern. Many have proposed an uptick in marine diseases as a result of environmental changes including a warming climate, habitat modifications, trade and transfer of wildlife and aquaculture products, pollution, overharvesting of resources, and other anthropogenic impacts. These perturbations can disturb the delicate host-pathogen relationships and result in new diseases or exacerbate the existing diseases in a population. Diseases can lead to several direct and indirect effects in the ecosystem such as population declines and extinctions, and thereby a change in population dynamics, as …

From The Hubbard Model To Coulomb Interactions: Quantum Monte Carlo Computations In Strongly Correlated Systems, Zhi-Yu Xiao

Dissertations, Theses, and Masters Projects

The study of interacting quantum many-body systems poses one of the main challenges in areas including condensed matter physics, nuclear physics, cold atoms physics, quantum chemistry, and materials science. Currently, no general approach is capable of handling the full complexity of interacting quantum systems, providing systematically accurate results across different ranges of many-body models and materials. The continued development of more general and more accurate numerical methodologies is instrumental in meeting the challenges of understanding and predicting the properties of interacting quantum systems. Quantum Monte Carlo (QMC) methods represent an important class of many-body techniques extensively employed in studying correlated …

Efficient Parallelization Of Irregular Applications On Gpu Architectures, Qihan Wang

Dissertations, Theses, and Masters Projects

With the enlarging computation capacity of general Graphics Processing Units (GPUs), leveraging GPUs to accelerate parallel applications has become a critical topic in academia and industry. However, a wide range of irregular applications with a computation-/memory-intensive nature cannot easily achieve high GPU utilization. The challenges mainly involve the following aspects: first, data dependence leads to a coarse-grained kernel; second, heavy GPU memory usage may cause frequent memory evictions and extra overhead of I/O; third, specific computation patterns produce memory redundancies; last, workload balance and data reusability conjunctly benefit the overall performance, but there may exist a dynamic trade-off between them. …

Environmental Education In The Classroom: Selected Early-Career Teachers' Experiences Navigating Pre-Service And In-Service Activity Systems, Sarah Mcguire Nuss

Dissertations, Theses, and Masters Projects

Recent publications argue that to prepare teachers of all grade levels to be confident and competent in incorporating environmental education into their classrooms, pre-service teacher training is effective (e.g., J. T. McDonald & Dominguez, 2010). But the systems in which teachers learn and work are complex, making professional learning about, and implementation of, environmental education both disparate and limited (Franzen, 2017). This study sought to understand the nature of participants’ experiences within and between teacher preparation and in-service learning systems as they relate to environmental education. Cultural historical activity theory (CHAT) provided a framework to allow for deeper understanding of …

Exploring Multi-Level Parallelism For Graph-Based Applications Via Algorithm And System Co-Design, Zhen Peng

Dissertations, Theses, and Masters Projects

Graph processing is at the heart of many modern applications where graphs are used as the basic data structure to represent the entities of interest and the relationships between them. Improving the performance of graph-based applications, especially using parallelism techniques, has drawn significant interest both in academia and industry. On the one hand, modern CPU architectures are able to provide massive computational power by using sophisticated memory hierarchy and multi-level parallelism, including thread-level parallelism, data-level parallelism, etc. On the other hand, graph processing workloads are notoriously challenging for achieving high performance due to their irregular computation pattern and unpredictable control …

Roles Of Hydrodynamics And Topographies On The Transport Of Dissolved Material, Particulates, And Harmful Algae In Chesapeake Bay, Jilian Xiong

Dissertations, Theses, and Masters Projects

Estuaries are highly productive and characterized by complex shoreline geometry and topography. Multiple materials produced within or transported into estuaries include non-living dissolved/particulate materials and living organisms. Estuarine circulation determines material transport and distributions, which further impact estuarine ecosystem to support abundant fauna/flora and their vulnerability to escalated anthropogenic inputs. Short-term material transport process in Chesapeake Bay (CB) has been studied for years, yet its long-term characteristics and the transport of materials with settling and biological behaviors that interact with physical transport have not been fully studied. This study aims to understand the transport of non-living and non-motile dissolved/particulate materials, …

The Fate And Transport Of Nitrogen In Subterranean Estuaries, Stephanie J. Wilson

Dissertations, Theses, and Masters Projects

The subterranean estuary (STE) is a subsurface ecosystem where fresh groundwater mixes with intruding, recirculated seawater at the coastline. Despite being present globally, STEs and their potential impacts as hotspots for biogeochemical processing, or as a source of nutrients to coastal systems, are not well understood. STEs have been recognized as highly reactive zones for biogeochemical reactions, which influence the fate and transport of nutrients, organic matter, and trace metals discharged to the coastal ocean. Biogeochemical processing of nitrogen (N) in STEs influences N in submarine groundwater discharge (SGD) including its availability for use by primary producers and cascading eutrophication. …

Feedbacks Among Benthic Metabolism, Nitrogen Cycling, And Intense Phytoplankton Blooms In The York River Estuary, Michelle H. Woods

Dissertations, Theses, and Masters Projects

Benthic-pelagic coupling is defined as the deposition of organic matter from the water column to the sediments, and the subsequent remineralization of this organic matter and release of inorganic nutrients back to the water column. This process plays an important role in determining the magnitude of benthic net community production (NCP), a metric that reflects the balance between gross primary production and respiration. Environmental factors, such as the presence or absence of intense phytoplankton blooms can influence the direction and magnitude of benthic-pelagic coupling and determine if benthic NCP is net autotrophic or heterotrophic. The objective this thesis was to …

Inclusive And Inelastic Scattering In Neutrino-Nucleus Interactions, Amy Filkins

Dissertations, Theses, and Masters Projects

Neutrino-nucleus cross section measurements can provide both insights into nuclear physics and important data that can be used to improve model predictions used for neutrino oscillation physics. Two measurements of neutrino-nucleus cross sections were performed using data from the MINERvA experiment, each probing different classes of neutrino interactions. Double and single-differential flux-integrated measurements of inclusive charged current neutrino-nucleus cross sections at a peak neutrino energy of 3.5 GeV are presented as a function of the longitudinal and transverse momentum of the muon produced in the interaction. Additionally, an analysis of charged-current deep inelastic scattering (DIS) of muon neutrinos was performed …

Ecosystem Enriching And Efficient Solar Energy: Exploring The Effects Of Pollinator-Friendly Solar Facilities On Ecosystem Function And Solar Panel Efficiency, Jordan Martin

Dissertations, Theses, and Masters Projects

As the solar energy industry grows, many hundreds of thousands of acres of land will be transformed into solar panel facilities. With this large change in land use, there is the opportunity to promote biodiversity and support pollinators by using pollinator-friendly management practices at the solar facilities. This paper explores the ecological and economic effects of a pollinator-friendly solar facility compared to a turfgrass solar facility.

I hypothesized that a pollinator-friendly solar facility would be functionally equivalent in pollinator support and overall insect diversity to a pollinator-friendly non-solar field and that both sites would have far greater pollinator support and …

Barrier-Island Dynamics: Transgression, Regression, And State Changes, Justin Lee Shawler

Dissertations, Theses, and Masters Projects

Barrier islands provide critical habitat for shorebirds and buffer backbarrier and inland coastal habitats and communities from the direct effects of storms and wave energy. Yet, barrier systems are under threat from these very same processes. In particular, whereas long-term barrier behavior and landward migration rate is directly related to the rate of sea-level rise, decadal to centennial barrier-island dynamics are more complicated, and often highly localized. Barrier-island dynamics—including state changes between seaward growth and landward migration—are driven by a complex interplay of forcings and interactions, including changes in longshore and cross-shore sediment fluxes, underlying geology and slope, barrier-marsh and …

Electronic Transport In Topological Superconducting Heterostructures, Joseph Jude Cuozzo

Dissertations, Theses, and Masters Projects

In this dissertation, we study Andreev transport and Josephson effects in topological superconducting heterostructures. We study consider two platforms: quantum Hall-superconductor (QH-SC) heterostructures and Josephson junctions. In the first platform, we study QH graphene-SC systems with a focus on the influence symmetry-breaking effects have on Andreev transport. In graphene, valley and spin degeneracy lead to an approximate SU(4) symmetry that is reflected in the approximate 4-fold degeneracy of graphene's Landau levels (LL). We develop an effective low-energy description of Andreev edge states that takes into account the correction to the drift velocity of the QH-SC edge modes due to SU(4) …

Exploring The Photophysics Of Brown Carbon Chromophores Using Laser-Based Spectroscopy And Computational Methods, Megan Elizabeth Alfieri

Dissertations, Theses, and Masters Projects

Atmospheric aerosols are made up of suspended liquids and solids in the atmosphere. These aerosols play a very important role in the solar energy exchange in Earth’s atmosphere as well have dramatic impact on human health. Different aerosols have different effects on the atmosphere depending on the physical properties of the aerosols.

The purpose of this research project is to understand how the structure of molecular chromophores impacts the solar absorption properties of aerosols. We propose a series of laboratory studies to investigate the outcomes from solar absorption of brown carbon chromophores: 1-phenylpyrrole, 2-phenyl-1-H-pyrrole, 2-phenylimadazole, as well as water complexes. …