Physical Sciences and Mathematics Commons^™

Hysplit In Simulating The Atmospheric Dispersion Of Hazardous Aerosols: A Case Study In St. Louis, Missouri, Ahmet Tolga Odabasi

Masters Theses

"Atmospheric dispersion and transmission play an important role in the behavior and effects of air pollution. Human health can be adversely affected by air pollution in a variety of ways, both immediately and over time. The Hybrid Single Particle Lagrangian Integrated Trajectory Model (HYSPLIT) modeling program, a computer model and software package, tracks the transport trajectories and distributions of air pollution and various pollutants, including radioactive pollutants, in the atmosphere. It also facilitates research on pollution sources. This study simulated the transport of hazardous aerosols in St. Louis region for the years 2020, 2021, and 2022 using the HYSPLIT modeling …

The Geodetic Strain Rates From Gnss In The North American-Carribean-Cocos Triple Junction In Guatemala And Implications For Seismic Hazard, Tanaya Kashyap

Masters Theses

"Geodetic velocity data are pivotal for deciphering seismic risks, providing initial constraints for crustal surface strain rates. Gaining an understanding of the 2D surface strain tensor across an entire area necessitates knowledge of the surface velocity field, yet geodetic data such as measurements from the Global Navigation Satellite System (GNSS) are dispersed across the Earth’s surface. In the current scope of study, we have employed various methodologies to estimate strain rates in Guatemala, utilizing GNSS velocity data and leveraging the open-source Python tool Strain_2D. Strain_2D facilitates the computation of strain rates through diverse methods applied to the same dataset and …

Scheduled Contrastive Loss In Continued Transfer Learning For Software Engineering Tasks, Aaron Michael Harris

Dissertations, Theses, and Masters Projects

Considerable research has been performed with regard to using text-to-text machine learning methods to perform various software engineering tasks. At the same time, contrastive learning has shown promise in other modalities, such as computer vision-related problems, and has been explored to some extent in terms of limited software engineering tasks. We demonstrate that contrastive loss, on its own, is insufficient to surpass current baselines for these tasks; however, we note that there is a high degree of orthogonality in the results from existing and contrastive models. We show that when our contrastive method is used as an additional transfer learning …

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 …

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. …

Low-Rank Matrix And Tensor Models For Data Science Applications, Jeremy Moulton Myers

Dissertations, Theses, and Masters Projects

Low-rank approximations play an important role in data science analysis and applications. When the model is linear and the data is represented as a matrix, the optimal rank-r approximation is given by the r dominant factors of the singular value decomposition (SVD). When the model is multilinear and the data is represented as a multi-way array called a tensor, the optimal rank-r approximation may not even exist. Nonetheless, the canonical polyadic decomposition (CP) provides a useful low-rank tensor approximation for interpretability and analysis in a way similar to the matrix SVD but across multiple axes simultaneously. In this dissertation, we …

Environmental Controls On Carbon And Nitrogen Cycling In Alaskan Arctic Coastal Lagoons, Brian Seung Taek Kim

Dissertations, Theses, and Masters Projects

At the intersection of land, sea, and atmosphere, coastal lagoons act as bioreactors, processing both terrestrial and autochthonous organic matter production before export to the coastal ocean. Approximately half of the Beaufort Sea coast is outlined by barrier island chains that enclose shallow lagoons and sounds. These lagoons are subject to extreme seasonal variations in ice cover, temperature, and salinity, yet are home to a diverse and productive food web. Bound between the arctic tundra and Beaufort Sea, these shallow systems receive and process resources from both sea and particularly land in the form of coastal erosion and riverine export. …

Transitions To Two-Hadron States From Quantum Chromodynamics, Felipe Ortega Gama

Dissertations, Theses, and Masters Projects

The rich spectrum of hadrons reflects the complexity of interactions between quarks and gluons confined within them. Most of these hadrons are extremely short-lived and are called resonances. Experimentally, they are observed indirectly through their effects on the energy distribution in scattering experiments. Additionally, the non-perturbative nature of Quantum Chromodynamics (QCD), which governs the dynamics of quarks and gluons, prevents the implementation of known analytical techniques for calculating transition and interaction rates between hadrons. Lattice QCD (LQCD), a numerical implementation of QCD, provides a non-perturbative approach to studying the spectrum, as long as we understand how to account for finite-volume …

Emergent Capabilities Of Llms For Software Engineering, Conor O'Brien

Dissertations, Theses, and Masters Projects

A growing interest for Large Language Models (LLMs) is how increasing their size might result in changes to their behavior not predictable from relatively smaller-scaled models. Analyzing these emergent capabilities is therefore crucial to understanding and developing LLMs. Yet, whether LLMs exhibit emergence, or possess emergent capabilities, is a contested question. Furthermore, most research into LLM emergence has focused on natural language processing tasks and models suited for them. We focus on investigating emergence in the context of software engineering, and recontextualize the discussion of emergence in the context of prior research. We propose a multifaceted pipeline for evaluating and …

The Effects Of Temperature, Flooding, And Goose Feces Addition On Greenhouse Gas Emissions And Ammonification In Four High-Latitude Soils From Western Alaska, Jenna M. Ross

Electronic Theses and Dissertations

The large carbon (C) stock of wetlands is vulnerable to climate change, especially in high latitudes that are warming at a disproportional rate. Likewise, low-elevation Arctic coastal areas will flood more frequently under climate change and sea-level rise, which may alter goose herbivory and fecal deposition patterns if geese move inland. While temperature, flooding, and feces impact soil C emissions, their interactive effects have been rarely studied. Here, I explore the impact of these interactions on CO2 and CH4 emissions and nitrogen (N) mineralization (ammonification) in soils collected from four plant communities in the Yukon-Kuskokwim (Y-K) Delta, a high latitude …

Accretion Of Warm Chondrules In Weakly Metamorphosed Ordinary Chondrites And Their Subsequent Reprocessing, Alexander M. Ruzicka, Richard C. Hugo, Jon M. Friedrich, Michael Tyler Ream

Geology Faculty Datasets

To better understand chondrite accretion and subsequent processes, the textures, crystallography, deformation, and compositions of some chondrite constituents in ten lithologies of different cluster texture strength were studied in seven weakly metamorphosed (Type 3) and variably shocked ordinary chondrites (Ragland—LL3 S1, Tieschitz—H/L3 S1, NWA 5421—LL3 S2, NWA 5205—LL3 S2, NWA 11905—LL3-5 S3, NWA 5781—LL3 S3, NWA 11351—LL3-6 S4) using optical and electron microscopy and microtomography techniques. Results support a four-stage model for chondrite formation. This includes 1) limited annealing following collisions during chondrule crystallization and rapid cooling in space prior to accretion, as evidenced by olivine microstructures consistent with dislocation …

Proof Of The Toponogov Conjecture On Complete Surfaces, Brendan Guilfoyle, Wilhelm Klingenberg

Department of Mathematics Publications

We prove a conjecture of Toponogov on complete convex planes, namely that such planes must contain an umbilic point, albeit at infinity. Our proof is indirect. It uses Fredholm regularity of an associated Riemann-Hilbert boundary value problem and an existence result for holomorphic discs with Lagrangian boundary conditions, both of which apply to a putative counterexample. Corollaries of the main theorem include a Hawking-Penrose singularity-type theorem, as well as the proof of a conjecture of Milnor’s from 1965 in the convex case.

Psilocybin And Music: Proposal To Study The Effects Of Music On Efficacy Of Psilocybin-Assisted Therapy For Treatment-Resistant Depression, Giorgi Gzirishvili

Senior Projects Spring 2024

This paper proposes an experiment to investigate the efficacy of psilocybin-assisted therapy for treating treatment-resistant depression (TRD) and assess the modulating effects of music on therapeutic outcomes. Previous studies have consistently incorporated music into psilocybin-assisted therapy for TRD but have not empirically isolated its effects. This research aims to fill this gap by introducing a controlled variable of music to explore its impact on therapy efficacy. I hypothesize that listening to the music playlist created by Johns Hopkins University during therapy sessions will significantly enhance therapeutic outcomes compared to a control group listening to ambient sounds. Participants, adults diagnosed with …

Finding Maximal Cap Sizes For Quad Card Decks Using Share Strings, Oliver William Pawelek

Senior Projects Spring 2024

This project introduces the concept of share strings and how they can be used to figure out maximal cap sizes for different decks of the card game EvenQuads. We prove that all caps must map to a share string with respect to a basis and that if no share strings exist for cap size k in a given dimension d, then the maximal cap size of that dimension M (d) must be less than k. We prove the maximal cap sizes up to dimension 7 and show that there are at most 8 possible share strings for 19-caps of dimension …

Applications Of Genetic Algorithms To Chess, Elliot M. Harris

Senior Projects Spring 2024

This thesis discusses the use of genetic algorithms to tune the parameters of a chess engine, resulting in a significant increase in playing strength. The design of the genetic algorithms builds on the 2008-2011 work of David-Tabibi et al. and Vázquez-Fernández et al. The overwhelmingly positive result presented in this thesis not only suggests a promising potential for genetic algorithm use to improve computer chess, but also supports the efficacy and potential of applying genetic algorithms to a broader set of use cases.

Symmetry And Structures Of Apn Functions And Sidon Sets, Darrion Thornburgh

Senior Projects Spring 2024

Let $\mathbb{F}_p^n$ be the $n$-dimensional vector space over $\mathbb{F}_p$. The graph $\mathcal{G}_F = \{ (x, F(x)) : x \in \mathbb{F}_p^n \}$ of a vectorial function $F \colon \mathbb{F}_p^n \to \mathbb{F}_p^m$ can have interesting combinatorial properties depending on varying cryptographic conditions on $F$. A vectorial Boolean function $F \colon \mathbb{F}_2^n \to \mathbb{F}_2^n$ is almost perfect nonlinear (APN) if there are at most $2$ solutions to the equation $F(x+a) + F(x) = b$ for all $a,b \in \mathbb{F}_2^n$ where $a \neq 0$. Equivalently, $F$ is APN if and only if $\mathcal{G}_F$ is a Sidon set, that is, a set in $\mathbb{F}_2^n$ where …

Results On $K$-Covers In The Game Quads, Daniel Melvin Rose-Levine

Senior Projects Spring 2024

This project explores the $k$-cover conjecture for the game Quads. The conjecture states that for all $k\in\mathbb{N}$, there exists a $k$-cover if and only if $k = 2$ or $k = \frac{2^n-2}{6}$ for some odd $n\in\mathbb{N}$ with $n>1$. We show that if $k$ is one of these values, then there exists a $k$-cover. We discuss partial results in the other direction, i.e., that these are the only values of $k$ for which there exists a $k$-cover.

Contrastive Learning, With Application To Forensic Identification Of Source, Cole Ryan Patten

Electronic Theses and Dissertations

Forensic identification of source problems often fall under the category of verification problems, where recent advances in deep learning have been made by contrastive learning methods. Many forensic identification of source problems deal with a scarcity of data, an issue addressed by few-shot learning. In this work, we make specific what makes a neural network a contrastive network. We then consider the use of contrastive neural networks for few-shot learning classification problems and compare them to other statistical and deep learning methods. Our findings indicate similar performance between models trained by contrastive loss and models trained by cross-entropy loss. We …

Effects Of Low-Cost, Low-Tech Tools For Riparian Restoration On Prairie Streams In Western South Dakota, James Andrew Joseph Bolyard

Electronic Theses and Dissertations

Despite making up less than two percent of the overall landscape in the arid and semi-arid western US, riparian areas are a crucial resource for agriculture, livestock, and wildlife. However, many have impaired function and reduced riparian cover. Low-Cost, Low-Tech Tools (LCLTT) are a subset of Process-Based Restoration (PBR) used for riparian restoration that were chosen for their cost-effectiveness and minimal technical requirements. LCLTT has been tested in mountainous areas of the western US but only recently implemented in the Northern Great Plains (NGP). Given their novelty as an approach toward restoration for the region, professional restoration and landowner communities …

A Gis Tool For Optimal Forage Species Selection, David B. Hannaway, Christopher Daly, Michael D. Halbleib, Linda Brewer, Sophie Baur, Chelsea Clark, Emilie Krecklow, Scott Bassett

IGC Proceedings (1993-2023)

To determine appropriate forage species for US ecoregions, geographic information technologies (GIS) are being used to create climatic and soil factor maps. Excel spreadsheets and RStudio are used to create response functions of forage species to minimum and maximum temperature, annual precipitation, soil pH, soil salinity, and salinity. National forage data and expert opinion will evaluate quantitative tolerances, seasonal yield profiles, and pollinator suitability. These maps and agronomic and livestock use information will be shared with forage specialists and farmers to provide alternatives for improved perenniality, increased diversity, and system circularity. Future work will include development and evaluation of climate …

A Quantitative Analysis Of Seaplane Accidents From 1982-2021, David C. Ison

International Journal of Aviation, Aeronautics, and Aerospace

This study aimed to assess and analyze all historical National Transportation Safety Board accident reports since 1982. For analysis, reports were bisected into seaplane (float, amphibian, and hull) and non-seaplane groups. Findings showed that there is a deficiency in the level of available detail on the seaplane fleet and cadre of seaplane pilots in the U.S. During the most recent ten years of complete data (2012-2021) showed a negative trend in all accidents and fatal accidents, although only the latter being statistically convincing. During this timeframe, seaplane accident pilots had significantly higher total time and age than other groups (non-seaplane …

The Impact Of Thunderstorms On Take-Off Data In South Africa, Quinton Jacobs Mr.

International Journal of Aviation, Aeronautics, and Aerospace

Aviation and meteorology are entwined disciplines, as aviation occurs in the atmosphere. Prevailing weather conditions at take-off are of utmost importance to aviation. This determines the payload of the aircraft and runway in use. Forecast verification is essential to aviation as it determines the quality of the forecasting products. The tolerances for take-off data are stringent and slightly relaxed tolerances are used in South Africa by mutual agreement.

There are six aerodromes in South Africa where Take-off Data are produced, in varying climatic conditions as South Africa is in both the tropics and midlatitudes. Thunderstorms are a common occurrence over …