Physical Sciences and Mathematics Commons^™

A Game Theoretical Approach To Optimal Pitch Sequencing, William Melville

Theses and Dissertations

This paper presents a game theoretical solution to the difficult challenge of optimal pitch sequencing. We model the batter/pitcher matchup as a zero-sum game and determine the equilibrium strategy for both the pitcher and batter. We conclude that the Stackelberg equilibrium and our newly defined decision point equilibrium serve as effective pitch sequencing strategies.

A Large-Scale Survey Of Brown Dwarf Atmospheres, Savanah Kay Turner

Theses and Dissertations

Brown dwarfs are substellar objects that fall in-between the smallest stars and largest planets in size and temperature. Due to their relatively cool temperatures, the atmospheres of these 'failed stars' have been shown to exhibit interesting properties such as iron, silicate, and salt clouds. Theoretical atmospheric models based on known physics and chemistry can be used as tools to interpret and understand our observations of brown dwarfs. I have fit archival and new infrared spectra of over 300 brown dwarfs with atmospheric models. Using the parameters of the best-fit models as estimates for the physical properties of the brown dwarfs …

Use And Misuse Of X-Ray Photoelectron Spectroscopy (Xps): Reproducibility, Gross Errors, Data Reporting, And Peak Fitting, George Hobbs Major

Theses and Dissertations

X-ray photoelectron spectroscopy (XPS) is the most widely used surface analysis technique for chemically probing surfaces. Its popularity stems from the large amount of information that can be gathered about the electronic states of the atoms it probes, including core shell information and valence electron information. Simple qualitative analysis (peak identification) can often be performed, but quantitative analysis is a much more complicated process. Although XPS usage has increased dramatically, so has the amount of erroneous analysis observed in the literature. In my thesis, I first present a perspective on how to improve the quality of surface and material data …

Comparative Gpr Analysis Of Carbonate Strandline Deposits, Sydney Adelaide Richards

Theses and Dissertations

The Bahamas Island archipelago grows by the precipitation and secretion of calcium carbonate. A majority of this growth is by lateral accretion of shoreline sedimentary deposits. Previous research is not clear on whether the growth is largely due to eustasy, sediment input from catastrophic events, or a combination of both. The Bahamas is an ideal location for studying Holocene carbonate generation and deposition, but there is limited research on the analysis of strandlines in relation to lateral accretion. Carbonate strandline deposits are commonly classified as low-energy beach ridge deposits. Previous researchers have primarily focused on ooid shoals and subtidal regions. …

Bézout Domains And Elementary Divisor Domains: Are They The Same?, Michael D. Walton

Theses and Dissertations

This thesis examines the connections between Bézout domains and elementary divisor domains. I establish what both of these domains are, and I provide some clarifying examples of each. I state and prove some key results that have been established already in the literature. I describe a process by which I tried to show a distinction between Bézout domains and elementary divisor domains, and then provide an explicit example which shows that this process as formulated would not lead to an example of a Bézout domain which is not an elementary divisor domain. Throughout the thesis, I also state open questions …

A Survey Of Graph Neural Networks On Synthetic Data, Brigham Stone Carson

Theses and Dissertations

We relate properties of attributed random graph models to the performance of GNN architectures. We identify regimes where GNNs outperform feedforward neural networks and non-attributed graph clustering methods. We compare GNN performance on our synthetic benchmark to performance on popular real-world datasets. We analyze the theoretical foundations for weak recovery in GNNs for popular one- and two-layer architectures. We obtain an explicit formula for the performance of a 1-layer GNN, and we obtain useful insights on how to proceed in the 2-layer case. Finally, we improve the bound for a notable result on the GNN size generalization problem by 1.

Skew Relative Hadamard Difference Set Groups, Andrew Haviland

Theses and Dissertations

We study finite groups $G$ having a nontrivial subgroup $H$ and $D \subset G \setminus H$ such that (i) the multiset $\{ xy^{-1}:x,y \in D\}$ has every element that is not in $H$ occur the same number of times (such a $D$ is called a {\it relative difference set}); (ii) $G=D\cup D^{(-1)} \cup H$; (iii) $D \cap D^{(-1)} =\emptyset$. We show that $|H|=2$, that $H$ has to be normal, and that $G$ is a group with a single involution. We also show that $G$ cannot be abelian. We give examples of such groups, including certain dicyclic groups, by using results …

Designing Resilient Agents Using Grammatical Evolution, Behavior Trees, And Finite Linear Temporal Logic, Aadesh Neupane

Theses and Dissertations

Resilience is essential for long-term autonomous agents. Swarm behaviors seen in bees, ants, birds, fish, and others are interesting because they resiliently perform complex coordinated tasks like foraging, nest-selection, flocking and escaping predators without centralized control or coordination. Conventionally, mimicking swarm behaviors with robots requires researchers to study actual behaviors, derive mathematical models, and implement these models as state machines. Since the conventional approach is time-consuming and cumbersome, this dissertation uses a grammatical evolution algorithm with Behavior Trees (BTs) to evolve behaviors that are resilient to different perturbations for foraging and nest maintenance tasks. The modular, reactive, and readable properties …

A Language-Model-Based Chatbot That Considers The User's Personality Profile And Emotions To Support Caregivers Of People With Dementia, Yeganeh Nasiri

Theses and Dissertations

Chatbots are programs that mimic human conversation using Artificial Intelligence (AI). Recent advances in natural language pro- cessing pave the way for chatbots to generate more human-like responses. Therefore, chatbots are finding more complex tasks to perform, such as emotional support which requires both understanding emotions and the ability to properly respond to them. This work presents a chatbot capable of identifying the user's personality and creating responses based on that. During this process, emotion detection is being used to detect and react to users' emotions. The chatbot uses a dynamic knowledge graph to save information as the conversation goes …

Unsupervised Categorical Clustering On Labor Markets, Matthew James Steffen

Theses and Dissertations

During this "white collar recession,'' there is a flooded labor market of workers. For employers seeking to hire, there is a need to identify potential qualified candidates for each job. The current state of the art is LinkedIn Recruiting or elastic search on Resumes. The current state of the art lacks efficiency and scalability along with an intuitive ranking of candidates. We believe this can be fixed with multi-layer categorical clustering via modularity maximization. To test this, we gathered a dataset that is extensive and representative of the job market. Our data comes from PeopleDataLabs and LinkedIn and is sampled …

Characterizing The Informativity Of Level Ii Book Data For High Frequency Trading, Logan B. Nielsen

Theses and Dissertations

High Frequency Trading (HFT) algorithms are automated feedback systems interacting with markets to maximize returns on investments. These systems have the potential to read different resolutions of market information at any given time, where Level I information is the minimal information about an equity--essentially its price--and Level II information is the full order book at that time for that equity. This paper presents a study of using Recurrent Neural Network (RNN) models to predict the spread of the DOW Industrial 30 index traded on NASDAQ, using Level I and Level II data as inputs. The results show that Level II …

Language Modeling Using Image Representations Of Natural Language, Seong Eun Cho

Theses and Dissertations

This thesis presents training of an end-to-end autoencoder model using the transformer, with an encoder that can encode sentences into fixed-length latent vectors and a decoder that can reconstruct the sentences using image representations. Encoding and decoding sentences to and from these image representations are central to the model design. This method allows new sentences to be generated by traversing the Euclidean space, which makes vector arithmetic possible using sentences. Machines excel in dealing with concrete numbers and calculations, but do not possess an innate infrastructure designed to help them understand abstract concepts like natural language. In order for a …

The Topology And Dynamics Of Surface Diffeomorphisms And Solenoid Embeddings, Xueming Hui

Theses and Dissertations

We study two topics on surface diffeomorphisms, their mapping classes and dynamics. For the mapping classes of a punctured disc, we study the $\ZxZ$ subgroups of the fundamental groups of the corresponding mapping tori. An application is the proof of the fact that a satellite knot with braid pattern is prime. For the mapping classes of the disc minus a Cantor set, we study a special type of reducible mapping class. This has direct application on the embeddings of solenoids in $\mathbb{S}^3$. We also give some examples of other types of mapping classes of the disc minus a Cantor set. …

Network Representation Theory In Materials Science And Global Value Chain Analysis, Mats C. Haneberg

Theses and Dissertations

This thesis is divided into two distinct chapters. In the first chapter, we apply network representation learning to the field of materials science in order to predict aluminum grain boundaries' properties and locate the most influential atoms and subgraphs within each grain boundary. We create fixed-length representations of the aluminum grain boundaries that successfully capture grain boundary structure and allow us to accurately predict grain boundary energy. We do this through two distinct methods. The first method we use is a graph convolutional neural network, a semi-supervised deep learning algorithm, and the second method is graph2vec, an unsupervised representation learning …

Sensitivity Of The Cupid Experiment To Bragg-Primakoff Conversion Of Solar Axions And Alps, Kevin P. Wilson

Theses and Dissertations

The author reports in this dissertation on the application of a technique to use bolometer detector arrays, such as those of the CUORE experiment and its proposed upgrade CUPID, to search for 14.4 keV Solar axions arising from an M1 nuclear transition of thermally excited ⁵⁷Fe in the Solar core. Density functional theory calculations performed using QU A N T U M ESPRESSO for Li₂MoO₄ enable the computation of a time-dependent axionto-photon conversion rate in the bolometer crystals. These calculations predict that the proposed CUPID detector will be sensitive to Solar axions or axion-like particles that …

Learning Analytics Through Machine Learning And Natural Language Processing, Bokai Yang

Theses and Dissertations

The increase of computing power and the ability to log students’ data with the help of the computer-assisted learning systems has led to an increased interest in developing and applying computer science techniques for analyzing learning data. To understand and investigate how learning-generated data can be used to improve student success, data mining techniques have been applied to several educational tasks. This dissertation investigates three important tasks in various domains of educational data mining: learners’ behavior analysis, essay structure analysis and feedback providing, and learners’ dropout prediction. The first project applied latent semantic analysis and machine learning approaches to investigate …

Evaluation Of A Radium-Thorium Disequilibrium Sediment Method Used To Model And Assess Porewater And Submarine Groundwater Exchange In The Coastal Marsh, Madeline R. Bodine

Theses and Dissertations

Ground, pore, and surface water exchange has been extensively studied in beach and near shore environments but has been long neglected in saltmarsh systems due to their complexity. Saltmarsh systems are of particular importance as they are the interface between fresh and saltwater. Saltmarshes impact carbon exchange, release and sequestration, and they process particulate matter. Understanding the characteristics of a marsh system such as the nutrient and particulate loads in conjunction with the flux of water exchange through the marsh provides a deeper understanding of these systems and can impact our understanding of the global water and carbon cycles, as …

Gamma Calibration Of Scintillators For The Muon Scattering Experiment, Anne Gloria Flannery

Theses and Dissertations

The MUon Scattering Experiment (MUSE) at the Paul Scherrer Institute seeks to measure the muon-proton and electron-proton elastic cross-sections in the same experiment by measuring the scattering angle of particles from a 115-160 MeV beam onto a liquid hydrogen target. The timing detectors, as well as several of other detectors in the experiment, are plastic scintillators. This document discusses a method for the energy calibration, using ²⁰⁸Tl, ²²Na, and 88Y sources, signal attenuation, and hit-position reconstructions of various timing detectors, as well as their function in the experiment as a whole. This method involves first attaining the pulse-height …

Extreme Covering Systems, Primes Plus Squarefrees, And Lattice Points Close To A Helix, Jack Robert Dalton

Theses and Dissertations

This dissertation considers three different topics.

In the first part, we prove that if the least modulus of a distinct covering system is 4, its largest modulus is at least 60; also, if the least modulus is 3, the least common multiple of the moduli is at least 120; finally, if the least modulus is 4, the least common multiple of the moduli is at least 360. The constants 60, 120, and 360 are best possible, they cannot be replaced by larger constants. We also show that there do not exist distinct covering systems with all of the moduli in …

Semantics-Based Data Security Models, Theppatorn Rhujittawiwat

Theses and Dissertations

In this dissertation, we studied how an adversary could attack databases and how the system could prevent or recover from such an attack. Our motivation to improve the current security capabilities of database management systems. We provided better recovery capabilities of database management systems by incorporating data provenance. We also expand our study to express security and privacy needs of data in the Internet of Things (IoT) environments such as a smart home environment. For this, we proposed a stream data security model to theoretically represent the data in the IoT network. We built a dynamic authorization model on our …

Bayesian Dependence Structure Analysis For Ordinal Data, Yang He

Theses and Dissertations

This dissertation explores different methods to study the dependence structure among many ordinal variables under the Bayesian framework.

Chapter 1 introduces ordinal data analysis methods, and the related literature works are briefly reviewed. An outline of the dissertation is put forward.

In Chapter 2, Gaussian copula graphical models with different priors of graphical Lasso, adaptive graphical Lasso, and spike-and-slab Lasso on the precision matrix are assessed and compared. The proposed models are well illustrated via simulations and a real ordinal survey data analysis.

In Chapter 3, adaptive spike-and-slab Lasso prior is proposed as an extension of Chapter 2. The developed …

Expanding Tailorable Nanomaterial Synthesis With Persistent Micelle Templates, Eric R. Williams

Theses and Dissertations

The control of block polymer micelle dimensions while in solution is critical for a range of emerging applications in diverse fields from drug delivery and nanoreactors to use as sacrificial templates for porous nanomaterials. When under kinetic control, micelles will maintain a constant average size and thus aggregation number (N_agg) through the suppression of chain exchange mechanisms. Such kinetic control effectively enables the decoupling of micelle dimensions from solution conditions. In other words, kinetically trapped micelles can resist reorganizations brough about by e.g., the addition of metal nanoparticles. However, such micelles are traditionally governed by a fickle �� …

Muon Intensity Measurement With The Majorana Demonstrator, Franklin Michael Adams Jr.

Theses and Dissertations

The Majorana Demonstrator (MJD) is a shielded radiation detection system located a mile underground at the Sanford Underground Research Facility (SURF) in South Dakota. The system aims to detect the theorized, rare process of neutrinoless double-beta decay. The Demonstrator utilizes an array of scintillating acrylic detectors to veto any signals induced by earth-penetrating cosmogenic muons and reach background levels necessary for the detection of neutrinoless double-beta decay. Utilizing the data collected by the muon veto system, an analysis has been done to determine the differential muon intensity. The complex geometry of the interlacing detector panels requires the use of Monte …

A Study Of Single Molecule Detection With Graphene Hall Bars, Kenneth Stephen Stephenson

Theses and Dissertations

In 2007, detection of individual molecules with a solid-state gas sensor was reported for first time by Schedin et al. where they used micromechanically-cleaved graphene for their sensing material, which exhibits isotropic and homogeneous conduction [1]. However, despite the novelty and popularity of their work, it has never been repeated. Further, we found their associated calculations to be self-inconsistent by a factor of 103 . So, hoping to account for and resolve this discrepancy, we outline the plan we had to reproduce their experiment. We also justify any substantial modifications, particularly our choice to use epitaxial graphene instead. Then, we …

Advancements In Parametric Modal Regression, Qingyang Liu

Theses and Dissertations

This dissertation considers statistical inference methods for parametric modal regression models. In Chapter 1, we motivate the mode as the measure of central tendency instead of the median or the mean with an example. Following the motivational example, we include an overview of existing modal regression models. Later, in the same chapter, we explain advantages of the parametric modal regression models over existing nonparametric modal regression models. In Chapter 2, we address issues in statistical inference brought in by data contaminated with measurement error. With measurement error in covariates, statistical inference methods designed for modal regression models with error-free covariates …

Detecting Spatially Varying Coefficient Effects With Conditional Autoregressive Models: A Simulation Study Using Social Determinants Of Health Screening Data, Reid J. Demass

Theses and Dissertations

Generalized linear models which include spatially varying coefficient terms allow researchers to determine if the association between predictor and outcome variables vary across geographic space. Such models are particularly applicable to research with public health data where interventions and limited health care resources must be allocated carefully. The integrated nested Laplace approximation (INLA) methodology available in the R INLA package is a popular tool to estimate spatially varying coefficients. To assess the performance of the estimation procedure, patient emergency department (ED) visits were simulated from data sourced from a pilot study at Prisma Health. The INLA technique was used to …

The Kinetic Control Of Polymer Micelles; Chemical Functionality, Material Interactions, And Equilibration, Taylor Larison

Theses and Dissertations

Polymer micelles have found significant uses in areas such as, energy storage devices, catalysis, opto-electronics, drug-delivery, oil additives, and nanoreactors. In many of these applications the overall micelle size (aggregation number) and chemical functionalization determines performance. To progress towards more advanced materials synthesized from the facile bottom-up approach with polymeric micelles the implementation and study of thermodynamic handles were investigated. Here the kinetic control of micelles was studied across a range of applications; independent control over micelle functionality, the spatial orientation of multiple metal oxide nanoparticles in mesoporous materials via self-assembly, and the use of small-angle neutron scattering (SANS) to …

Coordination Environment And Thermodynamics Of Colloidal Quantum Dots In Polar Solvents, Nuwanthaka Prasad Jayaweera Millaniyage

Theses and Dissertations

Colloidal semiconductor quantum dots (QDs) have been extensively investigated due to their attractive properties such as size-tunable absorption and emission spectra, large molar extinction coefficients, and significant photostability. These properties make them promising candidates for optoelectronic, photocatalytic, and biomedical applications. Common synthetic procedures of QDs produce nanocrystals capped with long-chain fatty acid derivatives which are stabilized in high boiling point solvents. Especially for bioimaging applications, the exchange of these native hydrophobic ligands with hydrophilic ligands should be performed, while preserving the smaller hydrodynamic radius. The coordination environment and thermodynamic parameters of the ligand exchanges should be carefully investigated to engineer …

Reactive End Capped Polybenzimidazole Oligomers For High Temperature Thermosets And Improved Membranes For Electrochemical Devices, Caroline Marie Rohlfing

Theses and Dissertations

Polybenzimidazoles (PBI) are heterocyclic polymers that possess high thermal and oxidative stability. The inherent strength and chemical and thermal stability of PBI make it ideal for use in extreme environments; however, the current processing of PBI molded parts makes the process practically and economically unfavorable. These intrinsic properties make PBIs of particular interest for many industrial applications, varying from fabrics to membrane materials to molded parts. Processing these molded parts is extremely difficult, as the high glass transition temperature and extremely high melting point (>500°C) of PBI result in poor flow properties of PBI resins even at high temperatures. …

Dust Production And Transport In A Long-Lived Fluvial-Eolian System In The Pampas Of South America, Blake Marcus Stubbins

Theses and Dissertations

Wind-blown dust from southern South America links the terrestrial, marine, atmospheric, and biologic components of Earth’s climate system. The Pampas of central Argentina (~33-40° S) contain an extensive upper Miocene to Holocene eolian record that spans the relatively warm conditions of the Late Miocene to cooler climates of the Plio-Pleistocene and Holocene. We collected 13 loess, paleosol, and fluvial samples from the upper Miocene Cerro Azul and Rio Negro Formations which resulted in n = 5129 new detrital zircon U-Pb ages. Late Miocene rivers conveyed sediment from northern Patagonia, the Andes adjacent to the Pampas, and the Sierras Pampeanas to …