Physical Sciences and Mathematics Commons^™

Computational Materials Science And Engineering: Model Development And Case Study, Yihan Xu

Theses and Dissertations

This study presents three tailored models for popular problems in energy storage and biological materials which demonstrate the application of computational materials science in material system development in these fields. The modeling methods can be extended for solving similar practical problems and applications.

In the first application, the thermo-mechanical stress concentrated region in planar sodium sulfur (NaS) cells with large diameter and different container materials has been estimated as well as the shear and normal stresses in these regions have been quantified using finite-element analysis (FEA) computation technique. It is demonstrated that the primary failure mechanism in the planar NaS …

Algebraic Relations Via A Monte Carlo Simulation, Alison Elaine Becker

Theses and Dissertations

The conjugation action of the complex orthogonal group on the polynomial functions on $n \times n$ matrices gives rise to a graded algebra of invariants, $\mathcal{P}(M_n)^{O_n}$. A spanning set of this algebra is in bijective correspondence to a set of unlabeled, cyclic graphs with directed edges equivalent under dihedral symmetries. When the degree of the invariants is $n+1$, we show that the dimension of the space of relations between the invariants grows linearly in $n$. Furthermore, we present two methods to obtain a basis of the space of relations; we construct a basis using an idempotent of the group algebra …

A Dynamic Programming Approach To Impulse Control Of Brownian Motions, Robin Braun

Theses and Dissertations

This thesis considers an impulse control problem of a standard Brownian motion under a discounted criterion, in which every intervention incurs a strictly positive cost. The value function and an optimal $(\tau_{*}, Y_{*})$ policy are found using the dynamic programming principle together with the smooth pasting technique. The thesis also performs a sensitivity analysis by analyzing the limiting behaviors of the value function and the $(\tau_{*}, Y_{*})$ policy when the fixed intervention cost converges to zero. It is demonstrated that the limits agree with the classic fuel follower problem.

The thesis next formulates and analyzes an $N$-player stochastic game of …

Dictionary-Based Data Generation For Fine-Tuning Bert For Adverbial Paraphrasing Tasks, Mark Anthony Carthon

Theses and Dissertations

Recent advances in natural language processing technology have led to the emergence of

large and deep pre-trained neural networks. The use and focus of these networks are on transfer

learning. More specifically, retraining or fine-tuning such pre-trained networks to achieve state

of the art performance in a variety of challenging natural language processing/understanding

(NLP/NLU) tasks. In this thesis, we focus on identifying paraphrases at the sentence level using

the network Bidirectional Encoder Representations from Transformers (BERT). It is well

understood that in deep learning the volume and quality of training data is a determining factor

of performance. The objective of …

Analysis On Some Basic Ion Channel Modeling Problems, Zhen Chao

Theses and Dissertations

The modeling and simulation of ion channel proteins are essential to the study of many vital physiological processes within a biological cell because most ion channel properties are very difficult to address experimentally in biochemistry. They also generate a lot of new numerical issues to be addressed in applied and computational mathematics. In this dissertation, we mainly deal with some numerical issues that are arisen from the numerical solution of one important ion channel dielectric continuum model, Poisson-Nernst-Planck (PNP) ion channel model, based on the finite element approximation approach under different boundary conditions and unstructured tetrahedral meshes. In particular, we …

Gross's Proof Of Local Existence For The Coupled Maxwell-Dirac Equations, Kimberly Jane Harry

Theses and Dissertations

The Maxwell-Dirac equations are a model for the interaction of a relativistic electron with an electromagnetic field. It is to be expected that the initial value problem will have an unique solution which exists for all time t >0, for all appropriate initial conditions. This is not yet known, but in 1966, Leonard Gross proved a local existence theorem. In this thesis, we will present an overview of Leonard Gross's proof.

Water Chemistry And Lake Dynamics Of Laguna Bacalar, Quintana Roo, Mexico, Ryan Matzuk

Theses and Dissertations

Laguna Bacalar in the Quintana Roo region is the second largest lake in Mexico and contains freshwater derived solely from groundwater. Local geology on the Yucatan Peninsula is karstic and the southern shoreline of Laguna Bacalar is spotted with a handful of cenotes that contribute substantial amounts of inflowing groundwater to the lake. This is shown by sonde profile data taken in one of the largest cenotes in the area. Outflow is dominated by a surface water outlet in the southern portion of the lake and an unknown amount of outflowing groundwater. During January of 2017 through 2019, UWM researchers …

Analysis Of The Continuity Of The Value Function Of An Optimal Stopping Problem, Samuel Morris Nehls

Theses and Dissertations

In order to study model uncertainty of an optimal stopping problem of a stochastic process with a given state dependent drift rate and volatility, we analyze the effects of perturbing the parameters of the problem. This is accomplished by translating the original problem into a semi-infinite linear program and its dual. We then approximate this dual linear program by a countably constrained sub-linear program as well as an infinite sequence of finitely constrained linear programs. We find that in this framework the value function will be lower semi-continuous with respect to the parameters. If in addition we restrict ourselves to …

Estimating Distortion Risk Measures Under Truncated And Censored Data Scenarios, Sahadeb Upretee

Theses and Dissertations

\begin{center}

ABSTRACT\\

\vspace{0.4in}

ESTIMATING DISTORTION RISK MEASURES UNDER TRUNCATED AND CENSORED DATA SCENARIOS

\end{center}

\doublespacing

\noindent

~In insurance data analytics and actuarial practice, a broad class of

risk measures -- {\em distortion risk measures\/} -- are used to capture

the riskiness of the distribution tail. Point and interval estimates of

the risk measures are then employed to price extreme events, to develop

reserves, to design risk transfer strategies, and to allocate capital.

When solving such problems, the main statistical challenge is to choose

an appropriate estimate of a risk measure and to assess its variability.

In this context, the empirical …

Information Retrieval Of Opioid Dependence Medications Reviews From Health-Related Social Media, Seyedeh Samaneh Omranian

Theses and Dissertations

Social media provides a convenient platform for patients to share their drug usage experience with others; consequently, health researchers can leverage this potential data to gain valuable information about users’ drug satisfaction. Since the 1990s, opioid drug abuse has become a national crisis. In order to reduce the dependency of opioids, several drugs have been presented to the market, but little is known about patient satisfaction with these treatments. Sentiment analysis is a method to measure and interpret patients’ satisfaction. In the first phase of this study, we aimed to utilize social media posts to predict patients’ sentiment towards opioid …

Asynchronous Monad For Reactive Iot Programming, Adam Bertrand Berger

Theses and Dissertations

The widespread adoption of Internet of Things (IoT) has given rise to systems which must reactively process signal data, while maintaining latency and throughput constraints. While the reactive programming paradigm partially addresses this problem, it does not offer a complete solution. We propose a design for a monad, AsyncM, and apply it to implement push-pull functional reactive programming (FRP) where side-effect bound events are performed in low-latency push streams, and time-series computations are performed in demand-driven pull streams. The design uses implicitly threaded cancellation tokens and continuation passing style to allow for implementations in languages which have single-threaded event-loops as …

Understanding Mechanochemical Processes On Surfaces Measured In Ultrahigh Vacuum, Resham Rana

Theses and Dissertations

Tribology is the study of friction and wear and of the energy dissipated when two surfaces slide against each other. A recent DOE report shows that improved lubricants could save ~103 exaJoules (1 exaJoule = 10^18 joules) per year, equivalent to 20% of the world’s total energy consumption. The focus of this work is to understand the surface chemistry and tribological reactions of model sulfur-, carbon-, and phosphorus-based lubricant additives to understand the mechanisms by which they operate. Previous work has shown that lubricant additives react by a novel mechanochemical process in which the force acting on the adsorbate accelerates …

Effect Of Force And Confinement On Chemical Reaction Kinetics, Alejandro Boscoboinik

Theses and Dissertations

This work studies model systems that are relevant to understanding the fundamentals of surface chemical processes. A Cu(100) single crystal surface modified by methyl thiolate species, formed from the adsorption of dimethyl disulfide, is used for modeling the effect of an external force in a chemical reaction. Furthermore, 2D-Zeolite is synthesized, characterized and postulated as a model system for studying chemistry in confined space. Furfural adsorption on Pd(111) is studied under different experimental conditions by means of infrared reflection-absorption spectroscopy. Furfural uptake experiments from sub-monolayer to multilayer coverages and sequential heating lead to an analysis of conformational changes and tilting …

Nuclear Magnetic Resonance Under Extreme Conditions, Anand Prashant Dwivedi

Theses and Dissertations

Nuclear Magnetic Resonance (NMR) is a prime characterization tool used to understand the structures and interactions in organic molecules, crystals, as well as non-crystalline materials. However, until now, the combination of NMR with high-pressure instrumentation such as Diamond Anvil Cells (DAC) was deemed unfeasible due to the high spatial and electrical costs of standard NMR electromagnets or the regular refill of cryogenic liquids for superconducting magnets. Standard NMR techniques also raises technical difficulties when combining high-pressure instrumentation with high-temperature techniques such as laser heating. In the first part of this thesis, we present the development of a low-cost and space-saving …

Development Of A Novel Sequential Injection-Proton Nmr Method For Determining Cathinones In Forensic Samples, Malati Thapa

Theses and Dissertations

A novel method was developed for the determination of low levels of Cathinones in authentic samples by interfacing Sequential Injection Analysis (SIA) to Proton Nuclear Magnetic Resonance Spectroscopy (NMR). In the first part of this study, solid phase extraction (SPE) was studied by SIA to preconcentrate the sample and remove matrix interferences. Phenylpropanolamine (PPA), Phenylephrine (PEP), and Methylephedrine (MEP) were studied as simulants for the Cathinones, representing primary, secondary, and tertiary amines, respectively. A variety of stationary, mobile, and eluent phases for several column geometries were examined, and a wide cylindrical column (20 mm6.6 mm) with a bed volume of …

Machine-Learning-Based Prediction Of Sepsis Events From Vertical Clinical Trial Data: A Naïve Approach, Tyler Michael Gaddis

Theses and Dissertations

Sepsis is a potentially life-threatening condition characterized by a dysregulated, disproportionate immune response to infection by which the afflicted body attacks its own tissues, sometimes to the point of organ failure, and in the worst cases, death. According to the Centers for Disease Control and Prevention (CDC) Sepsis is reported to kill upwards of 270,000 Americans annually, though this figure may be greater given certain ambiguities in the current accepted diagnostic framework of the disease.

This study attempted to first establish an understanding of past definitions of sepsis, and to then recommend use of machine learning as integral in an …

Reevaluating Order Fulfillment Decisions For E-Tailers Under True Simulated Operating Conditions, Amir H. Kalantari

Theses and Dissertations

This dissertation makes both a methodological and an applied contribution. From a methodological standpoint, this is among the very first works in the literature to explore the concepts of true simulated operating conditions and fully embedded decision-making algorithms. We illustrate the effectiveness of these concepts by applying them to an online retailer (i.e. e-tailer) order fulfillment decision making process.

Online shopping has completely transformed retail markets in recent years. For customers, it provides convenience, visibility and choice, and for retailers it provides market expansion opportunities, operational cost reduction, and many other advantages. There are fundamental differences between the supply chain …

Late Paleozoic Climatic Reconstruction Of Western Argentina: Glacial Extent And Deglaciation Of Southwestern Gondwana, Kathryn N. Pauls

Theses and Dissertations

Throughout its history Earth has experienced both icehouse and greenhouse conditions. Shifts and transitions from one end member to the other are driven by numerous driving mechanisms on global, orbital and more local scales. In particular, the late Paleozoic ice age (LPIA) is thought to have been driven by global drivers such as the drift of the Gondwanan continent across the South Pole, fluctuations in atmospheric CO2 concentrations, and Milankovitch cycles. It was also affected by more local and regional drivers such as active tectonism along accretionary margins and changes in atmospheric and oceanic circulation patterns. South American Gondwana provides …

Development Of An Advanced Zinc Air Flow Battery System (Phase 2), Jingyu Si

Theses and Dissertations

A zinc-air battery is the promising energy storage technology for large-scale energy storage applications due to its low cost, environmental friendliness, and high energy density. However, the electrically rechargeable zinc−air batteries suffer from poor energy efficiency and cycle life because of critical problems such as passivation, dendrite growth, and hydrogen evolution reaction. The proliferation of zinc−air batteries is limited.

The zinc-air flow battery combines the advantages of both a zinc-air battery and a redox flow battery. This combination permits the zinc-air flow battery to compete with the current leading battery technologies in the marketplace. A rechargeable Zn-air flow battery with …

Non-Discriminatory Service Robot Placement Using Geometric Median, Brian Boyd

Theses and Dissertations

Service robots are becoming increasingly common, and businesses are adopting their use at an increasingly rapid rate in order to reduce costs and provide efficiencies in performing mundane tasks. However, very little research has been performed in order to understand and address ethical concerns regarding their deployment and use.

One such concern is how one can ensure placement of a service robot such that is does not discriminate either in favor of or against individuals. This research explores techniques that can be used to provide a quantitative methodology to ensure fairness in terms of service robot placement such that discrimination …

Evaluation Of Text Document Clustering Using K-Means, Lisa Beumer

Theses and Dissertations

The fundamentals of human communication are language and written texts. Social media is an essential source of data on the Internet, but email and text messages are also considered to be one of the main sources of textual data. The processing and analysis of text data is conducted using text mining methods. Text Mining is the extension of Data Mining to text files to extract relevant information from large amounts of text data and to recognize patterns. Cluster analysis is one of the most important text mining methods. Its goal is the automatic partitioning of a number of objects into …

Characterization Of Water Pathways And Hydrolytic Weakening Within Naturally Deformed Quartz Grains Along The Willard Thrust Fault, Utah, Charles Alexander Martin

Theses and Dissertations

Evidence of water infiltration was examined in naturally deformed quartzite clasts from diamictite of the Mineral Fork Formation sampled from Antelope Island in the Great Salt Lake, Utah. The diamictite deformed via subsimple shear in the footwall of the Willard thrust fault and displays spatial variations in strain intensity. Evidence of water infiltration was investigated utilizing three complimentary techniques: standard petrographic microscopy to identify microstructures and interpret deformation mechanisms; scanning electron microscopy cathodoluminescence (SEM-CL) to create maps of healed microfractures and subgrain boundaries related to pathways of fluid infiltration; and synchrotron-source Fourier-transform infrared spectroscopy (FTIR) to create micron-scale water absorbance …

Simulating The Effects Of Urbanization And Climate Change On Ground Water Recharging Using The Usgs Precipitation And Runoff Modelling System (Prms), Kenneth Oanes

Theses and Dissertations

The Root River watershed, located in southeastern Wisconsin, was selected to be the subject of a study modeling the impacts of urbanization and climate change on groundwater recharge. Historical and projected (2035) land use data for the study area was sourced from the Southeast Wisconsin Regional Planning Committee (SEWRPC). The USGS Precipitation and Runoff Modelling System (PRMS) was selected to estimate recharge from a 35-year period of historical climate data (1980-2014). PRMS was run for the full 35-year time period under each land-use scenario and model outputs for evapotranspiration (ET), runoff, and recharge were calculated on a daily time-step.

Model …

Biomarker Development For Use In Regression Calibration, Yiwen Zhang

Theses and Dissertations

It is challenging to alleviate systematic measurement error in self-reported data when studying the associations between dietary intakes and chronic disease risk. The regression calibration method has been used for this purpose when an objectively measured biomarker that satisfies a classical measurement error assumption is available. The requirement for the biomarkers needs to be quite strong and very few dietary intake biomarkers as such have been developed. Feeding studies provide opportunities to develop such potential biomarkers using regression methods with a much larger variety of dietary variables. However, the measurement error for the resulting biomarkers will be of Berkson type …

Infant Mortality In The United States: Socioeconomic Factors Predicting Infant Survival In Late Neo-Natal And Post Neo-Natal Infants From Birth Certificate Data, Mark Brunk-Grady

Theses and Dissertations

According to the Centers for Disease Control and Prevention, the infant mortality rate in the United States in 2018 was 5.6 deaths per 1000 live births. Infant mortality is defined as a child being born alive but dying before their first birthday. This study aimed to determine if adding socioeconomic factors to traditional predictive survival models improved the predictive power in terms of survival for late and post neonatal infants. Secondly, this study looked to develop a risk score to and predict which mothers would be classified as “High” or “Low” risk for infant death.

Data were analyzed from a …

An Investigation Into The Trophic Magnification Of Polychlorinated Biphenyls In The Lake Michigan Food Web, Philip Hurst

Theses and Dissertations

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants known to contribute to several adverse health conditions in humans including cancers and a suite of liver diseases. While there exist 209 unique PCB congeners, the World Health Organization has identified 12 that pose the greatest health risk to humans due to these congeners’ functional similarity to dioxins, another notoriously toxic class of contaminants. Along with methylmercury, PCBs are the primary drivers behind fish consumption advisories in the Great Lakes. These guidelines are informed primarily by surveys of contaminants in freshwater biota. However, the proliferation of invasive species, such as …

Numerical Solution Of A Class Of Stochastic Functional Differential Equations With Financial Applications, Laszlo Nicolai Fertig

Theses and Dissertations

After a brief review of the Euler and Milstein numerical schemes and their convergence results

for stochastic differential equations (SDEs) and stochastic functional differential equations

(SFDEs), the thesis next proposes two specific SFDEs. The classical Euler and Milstein

schemes are developed to find the numerical solutions of these SFDEs, which are then compared

with the Ornstein-Uhlenbeck and a modified Ornstein-Uhlenbeck processes. These

results are further used to build four different but related stochastic models for stock prices.

The fitness of these models is analyzed by comparing real market data. The thesis concludes

with a numerical study for option pricing for …

A Feasibility Study Of Microbialites As Paleomagnetic Recorders, Ji-In Jung

Theses and Dissertations

Microbialites are carbonate organosedimentary deposits formed by benthic microbial communities that trap and bind detrital sediments, and/or inorganic and biologically influenced calcification. Any ferromagnetic particles incorporated into the microbialite structure have the potential to preserve variations in Earth’s magnetic field. A paleomagnetic record in microbialites would be useful for reconstructing the geomagnetic field because it may record at a high temporal resolution based on estimated growth rates, thus preserving relatively short-period variations of the Earth’s magnetic field. In addition, microbialites can be found in the geologic record going back ~3.5 Ga, hence potentially providing information on very ancient variations in …

Smoothed Quantiles For Claim Frequency Models, With Applications To Risk Measurement, Ponmalar Suruliraj Ratnam

Theses and Dissertations

Statistical models for the claim severity and claim frequency variables are routinely constructed and utilized by actuaries. Typical applications of such models include identification of optimal deductibles for selected loss elimination ratios, pricing of contract layers, determining credibility factors, risk and economic capital measures, and evaluation of effects of inflation, market trends and other quantities arising in insurance. While the actuarial literature on the severity models is extensive and rapidly growing, that for the claim frequency models lags behind. One of the reasons for such a gap is that various actuarial metrics do not possess ``nice'' statistical properties for the …

Analysis Of Inventory Models With Random Supply Using A Long-Term Average Criterion, Lars Moestue

Theses and Dissertations

In this thesis we will use different numerical algorithms for inventory models, where the inventory level is described by a stochastic differential equation and therefore random. Furthermore we assume that order supply is randomly distributed. The goal is to find the optimal order strategy to minimize the long-term average costs.\\

This stochastic problem can be reformulated as non-linear optimization problem. However the problems are too complex to solve by hand, so we need to use numerical optimization algorithms and for some of the models even numerical integration methods. \\

These algorithms then can be used to analyze some properties and …