Physical Sciences and Mathematics Commons^™

Variational Bias Sampling For Collaborative Filtering Recommender Systems, Prisca Stephens

Theses and Dissertations

Advancements in digitalization has yielded enormous growth of data on online platforms, overwhelming users with multitude of options to choose from. Recommender systems narrow down these options to a few relevant ones thereby facilitating the decision-making processes for users. This study presents a framework for integrating variational bias sampling into model-based collaborative filtering techniques for recommender systems. Variational bias sampling is a novel and unique way to account for random factors that affect explicit ratings in collaborative filtering recommender systems. A Gaussian distribution is used to model all the possible random factors that could affect ratings. Sampling user and item …

A Study Of Quantitative Reasoning Instructors’ Choices And Motivations When Teaching Quantitative Reasoning For The First Time, Trish Ann Harding

Theses and Dissertations

This qualitative study delves into the instructional decision-making processes of post-secondary instructors teaching quantitative reasoning (QR) courses for the first time. The study aims to address the gap in understanding how first-time QR instructors navigate the complexities of curriculum design and pedagogical strategies, and how these experiences contribute to their professional development. The research questions center on identifying the instructional decisions made by these instructors, exploring the factors influencing their decision-making, and understanding the impact of exercising agency has on their professional development. Through in-depth exploration, this study seeks to shed light on the challenges and opportunities faced by first-time …

How Mathematics Instructors Foster The Development Of Black Students' Mathematics Identity In Undergraduate Active Learning Mathematics Courses, Ashly J. Olusanya

Theses and Dissertations

Black students must overcome unique challenges to succeed in mathematics. Educators are tasked with identifying equitable teaching practices to support these students. Active learning (AL) is a teaching pedagogy that engages students in rigorous mathematical activities and encourages student participation. This research study will explore the professors’ beliefs about how students learn mathematics and why they use active learning in their collegiate mathematics courses. The study explores the connections between these beliefs and their reported use of instructional practices. The study also identifies the instructors’ beliefs about developing students’ mathematics identities, particularly their Black …

A Study On A Vector Complex Modified Korteweg-De Vries Equation, Changyan Shi

Theses and Dissertations

In this thesis, we systematically study a vector complex modified Kordeweg-de Vries equation by combining Hirota's bilinear method and the the Kadomtsev–Petviashvili (KP) reduction method. This vector nonlinear equation is a multi-component generalization of the well-known modified Kordeweg-de Vries (mKdV) equation and can be reduced to the known Hirota equation, Sasa-Satsuma (SS) equation, Sasa-Satsuma-mKdV equation as well as coupled Sasa-Satsuma equation. First, we bilinearize the vector complex mKdV equation under both the zero and nonzero boundary conditions by introducing auxiliary tau functions. Then, starting from two sets of bilinear equations of multi-component KP hierarchy and single-component KP-Toda …

Soil Carbon Sequestration Efforts In Arid And Semi-Arid Climates Under Conservation Agriculture And Reforestation, Samantha Lynn Colunga

Theses and Dissertations

Soil organic carbon (SOC) plays a vital role in the global carbon cycle and aids in climate change mitigation. However, deforestation and intensive agricultural practices threaten topsoil and carbon (C) pools through soil disturbances releasing vast amounts of carbon dioxide (CO2) by enhancing the decomposition of organic materials. Degraded soils typically lack stable aggregates, nutrient and water retention, and overall low fertility. In arid and semi-arid regions, soils are in an even more dire situation, as low precipitation and high temperatures slow down the accumulation of SOC. This thesis has two objectives: 1) to evaluate whether conservation tillage practices increase …

Representation Learning For Generative Models With Applications To Healthcare, Astronautics, And Aviation, Van Minh Nguyen

Theses and Dissertations

This dissertation explores applications of representation learning and generative models to challenges in healthcare, astronautics, and aviation.

The first part investigates the use of Generative Adversarial Networks (GANs) to synthesize realistic electronic health record (EHR) data. An initial attempt at training a GAN on the MIMIC-IV dataset encountered stability and convergence issues, motivating a deeper study of 1-Lipschitz regularization techniques for Auxiliary Classifier GANs (AC-GANs). An extensive ablation study on the CIFAR-10 dataset found that Spectral Normalization is key for AC-GAN stability and performance, while Weight Clipping fails to converge without Spectral Normalization. Analysis of the training dynamics provided further …

A Statistical Fetch Model For Water Wave Glint Correction Using Worldview-3 Imagery, Amanda Jade Quintanilla

Theses and Dissertations

Sun glint in satellite imagery of the water surface contaminates the upwelling signal received by a detector. Many models exist that attempt to correct for this wave facet effect and phenomena. In this work a model for sun glint correction is created using the comparison of image transects between two nearly simultaneously collected images of the same area, although with differing sensor geometry. One image utilized in this research is almost entirely glint free while the other is contaminated by water wave facet glint. Although many models for removing sun glint exist based on various techniques, none are completely accurate, …

Unraveling The Physics Of Quasar Jets Using Hst Polarimetry, Devon Clautice

Theses and Dissertations

We present a multiwavelength study of three high-power FR II (quasar) jets -- 3C 273, PKS 0637-752, and 1150+497 -- with an emphasis on new high-quality Hubble Space Telescope (HST) optical polarimetry and Chandra X-ray Observatory imaging. Relativistic jets from active galactic nuclei transport energy and mass from the supermassive black hole’s accretion region out to Megaparsec-scale lobes, with effects that feedback into galaxy formation and cluster energetics. We build on recent work which has called into question our fundamental understanding of FR II jet physics, and suggest that highly-efficient particle acceleration must be taking place in situ …

Deep Learning In Indus Valley Script Digitization, Deva Munikanta Reddy Atturu

Theses and Dissertations

This research introduces ASR-net(Ancient Script Recognition), a groundbreaking system that automatically digitizes ancient Indus seals by converting them into coded text, similar to Optical Character Recognition for modern languages. ASR-net, with an 95% success rate in identifying individual symbols, aims to address the crucial need for automated techniques in deciphering the enigmatic Indus script. Initially Yolov3 is utilized to create the bounding boxes around each graphemes present in the Indus Valley Seal. In addition to that we created M-net(Mahadevan) model to encode the graphemes. Beyond digitization, the paper proposes a new research challenge called the Motif Identification Problem (MIP) related …

Modelling Terrestrial And Potential Extraterrestrial Photopigments Via Density Functional Theory, Dorothea Illner

Theses and Dissertations

In the search for extraterrestrial life, biosignatures play a crucial role in identifying its putative traces. A commonly known and robust biosignature is the Vegetation Red Edge (VRE), which can be described as a sharp increase of reflectance observed from a planet and stems from the light absorption of photopigments in specific regions in the electromagnetic spectrum. For Earth, this VRE is known to occur around 700 nm, however, if the photopigments absorb light in different regions and have different structures the VRE could experience a wavelenght shift.

In this work, Chlorophyll a and a potential photopigment precursor called Phot0 …

Space Transformation For Open Set Recognition, Atefeh Mahdavi

Theses and Dissertations

Open Set Recognition (OSR) is about dealing with unknown situations that were not learned by the models during training. In OSR, only a limited number of known classes are available at the time of training the model and the possibility of unknown classes never seen at training time emerges in the test environment. In such a setting, the unknown classes and their risk should be considered in the algorithm. Such systems require not only to identify and discriminate instances that belong to the source domain (i.e., the seen known classes contained in the training dataset) but also to reject unknown …

Investigating The Impact Of Human-Centered Interface Design On The User Experience Of Mobile Device Users, Ruchir Gupta

Theses and Dissertations

In order to investigate the intricate interaction between interface design, user technological proficiency, and other components of the user experience, this research study used a mixed-method approach. The beginner user group—those with little experience or expertise with technology - were the main target audience. The important discovery emphasizes the substantial influence that careful design can have on improving the effectiveness and usability of interfaces for non-tech-savvy individuals. When using the suggested Interface B instead of the current Interface A, beginner participants' task completion times significantly improved, according to the user study. This underlines the significance of creating with the needs …

Development Of Chiral Lewis Base Catalysts For Chlorosilane-Mediated Asymmetric C-C Bond Formations, Changgong Xu

Theses and Dissertations

The chiral hydrazine is a crucial structural motif that serves as pivotal structural elements in numerous natural products and biologically significant molecules. We are particularly interested in the catalytic asymmetric reduction of hydrazones, as well as the catalytic asymmetric propargylation and allenylation of hydrazones, because they provide direct pathways to these enantio-enriched chiral building blocks. In this work, we will explore the potential of two different categories of chiral Lewis base catalysts in the said transformations.

Developed by another student in our group, axial-chiral 3,3’-triazolyl biisoquinoline N,N’-dioxides derived catalysts are tested and demonstrated its capability in activating various hydrazone …

Brain-Inspired Continual Learning: Rethinking The Role Of Features In The Stability-Plasticity Dilemma, Hikmat Khan

Theses and Dissertations

Continual learning (CL) enables deep learning models to learn new tasks sequentially while preserving performance on previously learned tasks, akin to the human's ability to accumulate knowledge over time. However, existing approaches to CL face the challenge of catastrophic forgetting, which occurs when a model's performance on previously learned tasks declines after learning the new task. In this dissertation, we focus on the crucial role of input data features in determining the robustness of CL models to mitigate catastrophic forgetting. We propose a framework to create CL-robustified versions of standard datasets using a pre-trained Oracle CL model. Our experiments show …

An Investigation Of The Interactions Of Gradient Coherence And Network Pruning In Neural Networks, Zachary Yauney

Theses and Dissertations

We investigate the coherent gradient hypothesis and show that the coherence measurements are different on real and random data regardless of the network's initialization. We introduce "diffs," an attempt at an element-wise approximation at coherence, and investigate their properties. We study how coherence is affected by increasing the width of simple fully-connected networks. We then prune those fully-connected networks and find that sparse networks outperform dense networks with the same number of nonzero parameters. In addition, we show that it is possible to increase the performance of a sparse network by scaling the size of the dense parent network it …

Trip - Transformer Interatomic Potential Predicts Realistic Energy Surface Using Physical Bias, Bryce Eric Hedelius

Theses and Dissertations

Accurate interatomic energies and forces enable high-quality molecular dynamics simulations, torsion scans, potential energy surface mapping, and geometry optimization. Machine learning algorithms have enabled rapid estimates of energies and forces with high accuracy. Further development of machine learning algorithms holds promise for producing general potentials that support dozens of atomic species. I present my own Transformer Interatomic Potential (TrIP): a chemically sound potential based on the SE(3)-Transformer. TrIP's species-agnostic architecture--using continuous atomic representation and homogenous graph convolutions--encourages parameter sharing between atomic species for more general representations of chemical environments, keeps a reasonable number of parameters, serves as a form of …

Towards A Practical Method For Monitoring Kinetic Processes In Polymers With Low-Frequency Raman Spectroscopy, Robert Vito Chimenti

Theses and Dissertations

Unlike liquids and crystalline solids, glassy materials exist in a constant state of structural nonequilibrium. Therefore, a comprehensive understanding of material kinetics is critical for understanding the structure-property-processing relationships of polymeric materials. Amorphous materials universally display low-frequency Raman features related to the phonon density of states resulting in a broad disorder band for Raman shifts below 100 cm-1, which is related to the conformational entropy and the modulus. This disorder band is dominated by the Boson peak, a feature due to phonon scattering because of disorder and can be related to the transverse sound velocity of the material, and a …

Head Tail Open: Open Tailed Classification Of Imbalanced Document Data, Chetan Joshi

Theses and Dissertations

Deep learning models for scanned document image classification and form understand- ing have made significant progress in the last few years. High accuracy can be achieved by a model with the help of copious amounts of labelled training data for closed-world classification. However, very little work has been done in the domain of fine-grained and head-tailed(class imbalance with some classes having high numbers of data points and some having a low number of data points) open-world classification for documents. Our proposed method achieves a better classification results than the baseline of the head-tail-novel/open dataset. Our techniques include separating the head-tail …

Unique K3 Surfaces With Purely Non-Symplectic Automorphism: Insights From Weighted Projective Spaceunique K3 Surfaces With Purely Non-Symplectic Automorphism:\\Insights From Weighted Projective Space, Elizabeth Melville

Theses and Dissertations

K3 surfaces have garnered attention across various fields, from optics and dynamics to high energy physics, making them a subject of extensive study for many decades. Recent work by mathematicians, including Brandhorst [1], has focused on non-symplectic automorphisms, aiming to categorize K3 surfaces that admit such automorphisms. Brandhorst made a list of unique K3 surfaces with purely non-symplectic automorphisms and established specific criteria for a K3 surface to be isomorphic to one on his list. This thesis aims to provide an alternative representation of select K3 surfaces from Brandhorst's list. While Brandhorst predominantly characterizes these surfaces as elliptic K3 surfaces, …

The Generation Of Terahertz Light And Its Applications In The Study Of Vibrational Motion, Aldair Alejandro

Theses and Dissertations

Terahertz (THz) spectroscopy is a powerful tool that uses ultrashort pulses of light to study the properties of materials on picosecond time scales. THz light can be generated through a variety of methods. In our lab, we generate THz through the process of optical rectification in nonlinear optical (NLO) organic crystals. THz light can be used to study several phenomena in materials, such as spin precession, electron acceleration, vibrational and rotational motion. The work presented in this dissertation is divided into two parts: (1) the generation of THz light and (2) applications of THz light. The first portion of this …

Multifunctional And Moisture Tolerant Zinc-Based Mono- And Bi-Metallic Metal-Organic Framework (Mof) Thin Films, Emmanuel Agbata

Theses and Dissertations

Many applications of metal-organic frameworks (MOFs) are highly dependent on their structures. The type and consistency of structure inform their properties. Zinc-based MOFs are applicable in different fields because of the low toxicity of zinc materials and are therefore also useful for catalysis. While MOF-5, a zinc-based MOF with carboxylate linkers is moisture intolerant, a variant of this is moisture tolerant. The introduction of a nitrogen-based linker in the zinc MOF which renders the structure moisture-tolerant. This material has not been explored as much, despite its multifunctional properties. Furthermore, the growth of Zn-based bimetallics of this MOF has not yet …

Applying Mathematical Modeling To The Study Of Family Systems, Dahlia Maxwell

Theses and Dissertations

Mathematical modeling provides a powerful framework for insight into current scientific theories as well as hypothesis generation for further research. Despite its undeniable potential to enrich scientific advancement, the application of mathematical modeling remains conspicuously scarce in the field of family science. The complexity inherent in family dynamics, coupled with the intricate interplay of emotions in the individual, underscores the necessity of a robust analytical approach. Addressing this critical gap in the literature, this thesis introduces a sophisticated mathematical model of family dynamics integrating essential elements from family systems theory, emotion dynamics, and appraisal theory. The model is implemented as …

Advancing Single-Cell Proteomics Through Innovations In Liquid Chromatography And Mass Spectrometry, Kei Grant Isaac Webber

Theses and Dissertations

Traditional proteomics studies can measure many protein biomarkers simultaneously from a single patient-derived sample, promising the possibility of syndromic diagnoses of multiple diseases sharing common symptoms. However, precious cellular-level information is lost in conventional bulk-scale studies that measure tissues comprising many types of cells. As single cells are the building blocks of organisms and are easier to biopsy than traditional bulk samples, performing proteomics on a single-cell level would benefit clinicians and patients. Single-cell proteomics, combined with mass spectrometry imaging, can be used to analyze cells in their microenvironment, preserving spatial information. We have previously used laser-capture microdissection to isolate …

Robot Proficiency Self-Assessment Using Assumption-Alignment Tracking, Xuan Cao

Theses and Dissertations

A robot is proficient if its performance for its task(s) satisfies a specific standard. While the design of autonomous robots often emphasizes such proficiency, another important attribute of autonomous robot systems is their ability to evaluate their own proficiency. A robot should be able to conduct proficiency self-assessment (PSA), i.e. assess how well it can perform a task before, during, and after it has attempted the task. We propose the assumption-alignment tracking (AAT) method, which provides time-indexed assessments of the veracity of robot generators' assumptions, for designing autonomous robots that can effectively evaluate their own performance. AAT can be considered …

N-H Nhc Palladium Catalysts Derived From Unique 2-Phosphinoimidazole Precursors For C-C Cross Coupling Reactions And Application Of Slow Releasing Polymers Impregnated With Gibberellic Acid To Overcome Seed Dormancy For Land Reclamation, Alexandra Jean Setelin Larson

Theses and Dissertations

Organometallic chemistry is highly dependent upon the ligands which are employed on a metal's surface. These ligands control steric bulk and electronics of the metal center which can change the reactivity of the organometallic complex. Ligands that are standard in organometallic chemistry include phosphine ligands. These phosphine ligands have been utilized in the field since the 1960's and have shaped the development of many key organometallic catalysts. Phosphine ligands are easily functionalized and highly reactive. This increased reactivity, however, causes severe limitations as phosphine ligands are often unstable under standard benchtop conditions and must be handled both air and moisture …

Gt-Ches And Dycon: Improved Classification For Human Evolutionary Systems, Joseph S. Johnson

Theses and Dissertations

The purpose of this work is to rethink the process of learning in human evolutionary systems. We take a sober look at how game theory, network theory, and chaos theory pertain specifically to the modeling, data, and training components of generalization in human systems. The value of our research is three-fold. First, our work is a direct approach to align machine learning generalization with core behavioral theories. We made our best effort to directly reconcile the axioms of these heretofore incompatible disciplines -- rather than moving from AI/ML towards the behavioral theories while building exclusively on AI/ML intuition. Second, this …

Development Of Bifunctional Peptides As Scaffolds For Bifunctional Catalysis And A Novel Method Of Peptide Stapling Using Squaric Esters, Adam X. Wayment

Theses and Dissertations

Enzymes are some of nature's most powerful tools in chemical processes. However, their molecular complexity makes them difficult to synthesize and complicates their application in traditional organic synthesis. Peptides, a building block of enzymes, can be rapidly synthesized and have been used as a possible alternative in achieving enzyme-like catalysis. However, most peptide-based catalysts are limited in reaction-scope and are unable to incorporate traditional organic catalysts. We have designed a helical peptide scaffold capable of being functionalized with a wide variety of organocatalysts as well as transition-metal based catalysts. In order to understand how the peptide structure effects reactivity and …

Development Of Salinomycin Derivatives As Potential Anticancer Agents, Viren Soni

Theses and Dissertations

Salinomycin is a poly-ionophore antibiotic that was originally isolated from Streptomyces albus by Miyazaki and colleagues from Kaken Chemicals Co., Ltd., Tokyo, Japan. Salinomycin exhibits antimicrobial activity against Gram-positive bacteria including Bacillus subtilis, Staphylococcus aureus, Micrococcus flavus, Sarcina lutea, Mycobacterium spp. Some filamentous fungi, Plasmodium falciparum, and Eimeria spp. as well as protozoan parasites responsible for the poultry disease coccidiosis. Hence, it is used in veterinary medicine. In 2009 Gupta et al demonstrated that salinomycin selectively killed human breast cancer stem cells (CSCs) with great efficacy, and the mechanism of action of this novel CSCs molecule was explored. To name …

Mri Image Regression Cnn For Bone Marrow Lesion Volume Prediction, Kevin Yanagisawa

Theses and Dissertations

Bone marrow lesions (BMLs), occurs from fluid build up in the soft tissues inside your bone. This can be seen on magnetic resonance imaging (MRI) scans and is characterized by excess water signals in the bone marrow space. This disease is commonly caused by osteoarthritis (OA), a degenerative join disease where tissues within the joint breakdown over time [1]. These BMLs are an emerging target for OA, as they are commonly related to pain and worsening of the diseased area until surgical intervention is required [2]–[4]. In order to assess the BMLs, MRIs were utilized as input into a regression …

New Mathematics Teachers' Goals, Orientations, And Resources That Influence Implementation Of Principles Learned In Brigham Young University's Teacher Preparation Program, Caroline S. Gneiting

Theses and Dissertations

Research in mathematics education shows that new mathematics teachers struggle to implement reform teaching practices that they learned in their teacher preparation programs. In this study, the researcher observed and interviewed three new mathematics teachers (within five years of graduation) to further explore the question of why new teachers use or do not use what they learned in their teacher preparation program. The study uses an expanded version of Schoenfeld's decision-making theory of Orientations, Goals, and Resources. This theory proved useful in the analysis of the research data, providing a framework to incorporate and organize the numerous reasons suggested by …