Physical Sciences and Mathematics Commons^™

Hierarchical Quantized Autoencoders: Using Hierarchical Models For Data Compression Across Multiple Domains, Armani Lorenzo Rodriguez

Theses and Dissertations

In the era of vast data processing and transmission, sending data over a channel for downstream operations is a very common occurrence. The bandwidth of this data channel acts as a limiting factor in this operation, capping the amount of data that can be sent over a time period. Therefore, in addition to pursuing advancements in networking technology, there exists a need for more efficient means of data compression. Learned compression is the application of machine learning models to the data compression problem, and in this study, we leverage the ability of neural networks to learn the underlying structure of …

Study Of Modified Salinomycin Analogs On Inhibition Of Triple Negative Breast Cancer Metastasis And Invasion, Farnaz Malekmarzban

Theses and Dissertations

Triple negative breast cancer (TNBC) is a more aggressive type of breast cancer which contains faster growth, higher metastasis rate and worse prognosis. The main challenge toward treatment of this type of cancer is being heterogeneous. Recently, Salinomycin (SAL) has been considered as a potential agent for triple negative breast cancer treatment. However, chemical modification of SAL is needed to improve SAL selectivity to cations and decrease its cytotoxicity. The purpose of this study was to evaluate the effect of chemically modified analogs of SAL on the viability, metastasis, Wnt pathway as well as angiogenesis of Triple negative breast cancer …

Application And Development Of Ceragenins In Medical Device Coatings For Clinical Settings, Elliot E. Sherren

Theses and Dissertations

Hospital-acquired infections (HAIs) pose a significant and increasing threat to global health. One primary cause of this threat is increasing antibiotic resistance. As traditional antibiotics continue to grow less effective, there is an urgent need for novel antimicrobial strategies. This work explores the potential of ceragenins, also known as cationic steroid antimicrobials (CSAs), as a promising alternative to combat HAIs. Specifically, we investigated potential roles that CSAs can play in the context of multiple medical device coatings in healthcare settings. Ceragenins are synthetic mimic of antimicrobial peptides (AMPs) which exhibit broad-spectrum antimicrobial activity against many common pathogens that have been …

A Nordhaus-Gaddum Type Problem For The Normalized Laplacian Spectrum And Graph Cheeger Constant, Adam Widtsoe Knudson

Theses and Dissertations

We will study various quantities related to connectivity of a graph. To this end, we look at Nordhaus-Gaddum type problems, which are problems where the same quantity is studied for a graph $G$ and its complement $G^c$ at the same time. For a graph $G$ on $n$ vertices with normalized Laplacian eigenvalues $0 = \lambda_1(G) \leq \lambda_2(G) \leq \cdots \leq \lambda_n(G)$ and graph complement $G^c$, we prove that \begin{equation*} \max\{\lambda_2(G),\lambda_2(G^c)\}\geq \frac{2}{n^2}. \end{equation*} We do this by way of lower bounding $\max\{i(G), i(G^c)\}$ and $\max\{h(G), h(G^c)\}$ where $i(G)$ and $h(G)$ denote the isoperimetric number and Cheeger constant of $G$, respectively. We …

Potent And Selective Small Molecule Mcl-1 Inhibitor Demonstrates Anti-Myeloma Activity And Overcomes Chemotherapy Resistance, Omar Sami Faleh Al-Odat

Theses and Dissertations

Despite a record number of clinical studies investigating various anti-myeloma treatments, the 5-year survival rate for multiple myeloma (MM) patients in the US is only 55%, and nearly all patients relapse. Poor patient outcomes demonstrate that myeloma cells are "born to survive” which means they can adapt and evolve following treatment. Thus, new therapeutic approaches to combat survival mechanisms and target treatment resistance are required. Importantly, Mcl-1, anti-apoptotic protein, is required for the development of MM and treatment resistance. This study looks at the possibility of KS18, a selective Mcl-1 inhibitor, to treat MM and overcome resistance. Our investigation demonstrates …

An Empirical Study On Detecting And Explaining Global Structural Change In Evolving Graph Using Martingale, Tarun Teja Kairamkonda

Theses and Dissertations

There is a growing interest in practical applications involving networks of interacting entities such as sensor networks, social networks, urban traffic networks, and power grids, all of which can be represented using evolving graphs. Changes in these evolving graphs can signify shifts in the behavior of interacting entities or alterations in the patterns of their interactions. Identifying and detecting these changes is crucial for addressing potential challenges or opportunities in various domains. In this study, we propose an approach for detecting structure change in evolving graphs based on the martingale change detection framework on multiple graph features extracted over time. …

The Osteological Neutral Pose Of The Neck Of An Apatosaurine Sauropod Based On Virtual And Physical Models, Colin Don Boisvert

Theses and Dissertations

An array of sauropod taxa coexisted in Late Jurassic North America. How so many giant genera coexisted without competing for food is puzzling considering their potential metabolic requirements. One aspect of this question is neck posture, which has been much contested, both in terms of the intrinsic curvature of the neck and the resultant elevation of the head. Neck curvature is characterized by the Osteological Neutral Pose (ONP), wherein the intervertebral joints are in an undeflected state. This pose is crucial to understanding neck posture. The articulated series of presacral vertebrae 2-19 of an exceptionally well-preserved apatosaurine, BYU 18531, are …

"Vampire Plastics": An Investigation Of Poly(Olefin Sulfone) Depolymerization And Its Dust Mitigation Abilities, Alexandra Kathryn Kanani Gallion Stapley

Theses and Dissertations

The ubiquity of particulate contamination requires dust mitigation techniques to provide low-scatter surfaces and edges on sensitive optical devices in space. Poly(olefin sulfone)s have been shown to photodegrade with the assistance of a photobase generator when exposed to UV light (254 nm) and heat (120 °C). These polymers may be useful for minimizing dust on optical surfaces for space applications. However, their behavior in vacuum has not been fully characterized. We synthesized poly(2-methyl-1-pentene sulfone) (PMPS) and poly(1-hexene sulfone) (PHS) with and without a photobase generator. We studied the photodegradation (172 nm or 254 nm) of thin films in vacuum. Spectroscopic …

Implementing 1.5 Millimeter Internal Diameter Columns And A Portable Capillary Column Instrument Into Monoclonal Antibody Analytical Workflows, Benjamin Libert

Theses and Dissertations

Using 1.5 mm inner diameter (i.d.) columns to bridge the gap between routinely used 2.1 mm i.d. columns and capillary bore columns allows for a sequential but significant increase in performance without the need for specialized equipment associated with very low dispersion liquid chromatography (LC) systems. These 1.5 mm i.d. columns balance an increase in sensitivity compared to 2.1 mm i.d. columns (theoretically doubling the time-domain peak area in mass sensitive detectors for the same mass load), while mitigating the efficiency losses due to extra-column dispersion effects that are commonly observed with 1.0 mm i.d. columns. Here, the use of …

Reinforcement Learning For Robotic Tasks: Analyzing And Understanding The Learning Process Using Explainable Artificial Intelligence Methods, Brian J. Campana

Theses and Dissertations

As deep reinforcement learning (RL) models gain traction across more industries, there is a growing need for reliable agent-explanation techniques to understand these models. Researchers have developed explainable artificial intelligence (XAI) methods to help understand these 'black boxes'. While these models have been tested on many supervised learning tasks, there is a lack of examination of how these well these methods can explain hard reinforcement learning problems like robotic control. The sequential nature of learning RL policies and testing episodes create fundamentally different policies over time compared to more traditional supervised learning models. In this thesis, two important questions are …

An Exploration Of Causal Cognition In Large Language Models, Vicky Chang

Electronic Thesis and Dissertation Repository

Causal cognition, how beings perceive and reason about cause and effect, is crucial not only for survival and adaptation in biological entities but also for the development of causal artificial intelligence. Large language models (LLMs) have recently taken center stage due to their remarkable capabilities, demonstrating human-like reasoning in their generative responses. This thesis explores how LLMs perform on causal reasoning questions and how modifying information in the prompt affect their reasoning. Using 1392 causal inference questions from the CLADDER dataset, LLM responses were assessed for accuracy. With simple prompting, LLMs performed more accurately on intervention queries compared to association …

Framework For Bug Inducing Commit Prediction Using Quality Metrics, Alireza Tavakkoli Barzoki

Electronic Thesis and Dissertation Repository

This thesis relates to the topic of software defect prediction within the broader area of continuous software engineering. The approach presented in this thesis is employing source code and process metrics obtained for each commit, and is examining as to whether specific patterns, as the system moves from one commit to another, can predict an impending bug inducing commit. The thesis utilizes the SonarQube Technical Debt open source data which provides source code metrics and process metrics for each commit in 22 medium to large scale open source Apache projects.

Central to this research is the novel utilization of commits …

Impacts Of Stream Habitat Restoration On Macroinvertebrate Assemblages: A Systematic Literature Review, Morgan E. Seitzer

University Honors Theses

Globally, river restoration has become a popular tool for improving the health of a watershed and restoring ecosystem services, but still has significant knowledge gaps. In certain areas and scientific communities, special attention has been given to the response of macroinvertebrates as a measure of restoration success. This systematic literature review aims to highlight and discuss the patterns in studies that have comparable before-and-after restoration data on macroinvertebrates after reconnecting stream channels to their floodplains. Macroinvertebrate sampling is a simple if not time-consuming task that can reveal important data about habitat quality. Because they serve as an important food source …

Procedural Pre-Training For Visual Recognition, Connor S. Anderson

Theses and Dissertations

Deep learning models can perform many tasks very capably, provided they are trained correctly. Usually, this requires a large amount of data. Pre-training refers to a process of creating a strong initial model by first training it on a large-scale dataset. Such a model can then be adapted to many different tasks, while only requiring a comparatively small amount of task-specific training data. Pre-training is the standard approach in most computer vision scenarios, but it's not without drawbacks. Aside from the cost and effort involved in collecting large pre-training datasets, such data may also contain unwanted biases, violations of privacy, …

Zeros Of Convex Combinations Of Elementary Families Of Harmonic Functions, Rebekah Ottinger

Theses and Dissertations

Brilleslyper et al. analyzed a one-parameter family of harmonic trinomials, and Brooks and Lee analyzed a one-parameter family of harmonic functions with poles. Each family was explored to find the relationship between the size of the parameter and the number of zeros of the harmonic function. In this thesis, we examine convex combinations of members of these families. We determine conditions under which the critical curves separating the sense-preserving and sense-reversing regions are circular. We show that the number of zeros of a convex combination can be greater than the maximum number of zeros of either part.

Hardware Acceleration Of Numerical Methods For Solving Ordinary Differential Equations, Soham Bhattacharya

Theses and Dissertations

Along with the advancement in technology, the role of hardware accelerators is increasing consistently, delivering advancements in scientific simulations and data analysis in scientific computing, signal processing tasks in communication systems, matrix operations, and neural network computations in artificial intelligence and machine learning models. On the other hand, several high-speed computer applications in this era of high-performance computing often depend on ordinary differential equations (ODEs); however, their nonlinear nature can present a challenge to obtaining analytic solutions. Consequently, numerical approaches prove effective in delivering only approximate solutions to these equations. This research discusses the implementation of a customized hardware accelerator …

Microplastic Pollution In Stormwater: Preliminary Findings From The Oregon Coast, Jazmine Compton

University Honors Theses

Microplastics have become ubiquitous in marine environments and pose a risk to ecosystem, organismal, and human health. Stormwater runoff has been suggested to be a major contributor to marine microplastic pollution. This project aims to quantify the average concentration of microplastics in stormwater in a community on the Oregon Coast. To accomplish this, stormwater samples were collected from five sites in Cannon Beach, Oregon, and one sample was analyzed using a dissection microscope. Using this technique, the number, size, and composition of the microplastic particles were determined. The calculated concentration of microplastics in the stormwater sample was 12.21 MPs/L, and …

Henna Chatbot Capstone Review, Kobe Norcross

University Honors Theses

This thesis reviews the development of the Henna Chatbot, an AI-powered DEI consultant designed to provide personalized feedback to organizations. Sponsored by DEI consultant Arsh Haque, the project aims to address gaps in current DEI software, which often lacks team-specific feedback. The Henna Chatbot leverages GPT-3.5 Turbo to create an affordable SaaS platform where organizations can train Henna with their DEI values, and Henna will help organizations stay aligned with those values. The project spanned twenty weeks and was completed by a team of eight computer science students at Portland State University. The development process followed Agile methodologies, emphasizing effective …

Examining The Interaction Between Calcium Supplement Use, Demographics, And Lifestyle Factors On Bone Health In Women, Vix Talbot

University Honors Theses

Osteoporosis is a condition which poses a significant health threat, particularly among women during the menopause transition, where accelerated bone loss increases fracture risk. Calcium supplementation has been shown to be an important intervention to mitigate bone mineral density (BMD) decline during this and other periods of life. However, the efficacy of calcium supplementation is influenced by various individual factors, including demographics and lifestyle habits. This study investigates the interaction between calcium supplement use, and several interaction terms on bone health in women. Multiple linear regression analysis is employed to assess the impact of these factors on BMD. Data from …

Student Perceptions: How Stem Students Value Belonging Interventions, Elizabeth Runkel Baez

University Honors Theses

With the prioritization of increasing Science, Technology, Engineering, and Mathematics (STEM) graduates in the United States, researchers have become increasingly interested in how to promote STEM students' sense of belonging. Sense of belonging is considered a marker of persistence in STEM. Facilitated 'belonging interventions' are one way to strengthen a sense of belonging amongst STEM students. How students respond to, value, and understand these belonging interventions is relatively understudied. In this study, focus groups were conducted with STEM students from a single university to investigate how they value an in-class belonging activity. Qualitative thematic coding of focus group responses revealed …

Climate Justice Issues, Urban Heat Island Effect, And Trees As The Solution In Portland, Oregon, Cleo Needham

University Honors Theses

Portland, Oregon, is experiencing rising temperatures caused by climate change and urban heat island effect. High heat disproportionately impacts vulnerable communities in Portland, causing harm to physical and mental health. Trees are a solution that reduces temperatures in urban environments. A strategy called 3-30-300 helps create a structure for where to place trees to help people receive the benefits. There are challenges with trees, such as the space required, the significant cost, and the time it takes to mature. Using trees as a solution can support and protect vulnerable communities in Portland, Oregon.

Spin And Charge Transport In Metallic Ferrimagnets And Disordered Magnetic Oxides, Leopoldo A. Hernandez

Electronic Theses and Dissertations

Recent efforts have been exploring the use of thin film synthetic ferrimagnets and disordered magnetic oxides for applications in spintronic devices. Due to the antiferromagnetic exchange interaction, ferrimagnetic materials offer the ultrafast dynamics of the antiferromagnetic exchange, with a net magnetization that can be influenced externally. With two, or more, competing ferromagnet sublattices, interesting properties arise that depend on the final magnetic landscape after growth of the material and it’s inherent magnetic anisotropy energies. Properties such as magnetic compensation temperatures, and perpendicular magnetic anisotropy are attractive for applications in spintronic memory and logic devices, some already being implemented in MRAM …

Building Blocks For W-Algebras Of Classical Types, Vladimir Kovalchuk

Electronic Theses and Dissertations

The universal 2-parameter vertex algebra W_∞ of type W(2, 3, 4; . . . ) serves as a classifying object for vertex algebras of type W(2, 3, . . . ,N) for some N in the sense that under mild hypothesis, all such vertex algebras arise as quotients of W_∞. There is an ℕ X ℕ family of such 1-parameter vertex algebras known as Y-algebras. They were introduced by Gaiotto and Rapčák are expected to be building blocks for all W-algebras in type A, i.e, every W-(super) algebra in …

Differential Elliptic Flow Analysis Of Hadrons With Different Wuark Content In Simulated Pp Collisions, Elhussein Osama

Theses and Dissertations

According to current physics theories, it is assumed that in the first microsecond after the big bang, the universe was in a state of matter called Quark-Gluon Plasma (QGP), where the fundamental consistent of matters (quarks and leptons), were highly energetic, and floating around freely. Searching for such phase of matter; as the possible earliest signatures after the big bang, and among many other interesting experimental measurements, the jet quenching and elliptic flow are the most important ones, in the heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC) experiments.

The azimuthal anisotropy …

Statistical Modeling Of Knee Morphology And Material Properties Considering Diverse Populations, Gabrielle Jeannine Kindy

Electronic Theses and Dissertations

Total Knee Arthroplasty (TKA) is a widely performed surgical procedure aimed at alleviating pain and restoring function in patients with severe knee osteoarthritis. Despite its general success, disparities in postoperative outcomes have been observed across different racial and ethnic groups, with minority populations often experiencing less favorable results. One potential avenue for improving the generalizability of orthopaedic implants is using Statistical Shape and Intensity Models (SSIMs), which can be used to incorporate patient variability directly into the orthopaedic medical device development workflow through population-based finite element analysis.

This work aimed to construct an SSIM from a diverse subject set, incorporating …

Combinatorial Problems On The Integers: Colorings, Games, And Permutations, Collier Gaiser

Electronic Theses and Dissertations

This dissertation consists of several combinatorial problems on the integers. These problems fit inside the areas of extremal combinatorics and enumerative combinatorics.

We first study monochromatic solutions to equations when integers are colored with finitely many colors in Chapter 2. By looking at subsets of {1, 2, . . . , n} whose least common multiple is small, we improved a result of Brown and Rödl on the smallest integer n such that every 2-coloring of {1, 2, . . . , n} has a monochromatic solution to equations with unit fractions. Using a recent result of Boza, …

Trust, Transparency, And Transport: The Impact Of Privacy Protection On The Acceptance Of Last-Mile Drone Delivery, Jurgen Heinz Famula

Electronic Theses and Dissertations

A common set of problems commercial delivery companies face is finding ways to increase the efficiency and reliability of the “last mile” of a package’s journey, all while reducing operating costs. This need for efficiency has driven many companies to explore using unmanned aerial vehicles (UAVs), or drones, to get packages to their final destination. Although UAVs have great potential to help increase efficiency in commercial package delivery, this comes at a potential cost to the privacy of people who intersect the flight paths of these unmanned vehicles. This thesis explores the effect of a mobile phone application for commercial …

Capturing Latent Abilities And Latent Capacities Of Professional Golfers Using Nonlinear Mixed Effects Growth Modeling, Mac Wetherbee

Electronic Theses and Dissertations

This study demonstrates an effective and innovative approach to measuring the latent athletic abilities and capacities of professional golfers. I used nonlinear mixed effects growth modeling (e.g., Dynamic Measurement Modeling) to measure professional golfers’ ability levels and capacities for improvement. I accomplished this using a two-stage modeling approach. First, a crossed linear mixed effects model estimated each player’s ability level in each year. In the second stage, I used the results from the first stage to estimate several candidate nonlinear growth trajectories for players’ abilities over time. The quadratic growth trajectory was the best-fitting of these trajectories and was used …

Bridging The Geometric And Quantum Information Of Structured Light, Andrew Alexander Voitiv

Electronic Theses and Dissertations

In this Dissertation, we review the several advances we have developed for preparing and measuring the geometric and quantum information of structured light. The geometric phase acts as a memory of transformations undertaken by physical processes; quantum entanglement underpins quantum information science which explores the theoretical and technological applications of nonclassical correlations. Beginning with classical light, we demonstrate novel experiments and measurements of geometric phase that are enabled by spatially structuring laser beams. We then extend those concepts to complement the richer possibilities within quantum optics. Our work covers new abilities in tailoring and measuring the phase content of spatially-structured …

Establishment Of A Research Site At The Kennedy Mountain Campus For The Observation Of Airborne Particulate Matter, Alyssa Knaus

Undergraduate Theses, Capstones, and Recitals

This thesis explored particulate matter (PM) concentrations at two sites within the Colorado Front Range. The study utilized two models of PurpleAir PM sensors, Flex and SD-II, to provide real-time, accessible data on PM1, PM2.5, and PM10 mass concentrations with the goal of establishing the first research site at the Kennedy Mountain Campus (KMC). The first of the two sites used during this study was at a suburban location outside of Denver, CO. This period was used as an instrument intercomparison period in order to conduct instrument analysis. The initial findings from this period found significant correlations between PM concentration …