Physical Sciences and Mathematics Commons^™

Pt-Symmetry And Eigenmodes, Tamara Gratcheva

University Honors Theses

Spectra of systems with balanced gain and loss, described by Hamiltonians with parity and time-reversal (PT) symmetry is a rich area of research. This work studies by means of numerical techniques, how eigenvalues and eigenfunctions of a Schrodinger operator change as a gain-loss parameter changes. Two cases on a disk with zero boundary conditions are considered. In the first case, within the enclosing disk, we place a parity (P) symmetric configuration of three smaller disks containing gain and loss media, which does not have PT-symmetry. In the second case, we study a PT-symmetric configuration …

College Course Assignment: Maximality, Fairness, Scheduling, Emily Y. Gao

Computer Science Senior Theses

Course selection processes in universities are crucial for shaping students’ academic experiences. At Dartmouth College, undergraduates participate in a structured course selection process each term, governed by specific constraints and priorities. This thesis examines the optimization of course assignment algorithms within Dartmouth’s environment to enhance student satisfaction and maximize course enrollment. An initial investigation reveals that Dartmouth’s registrar effectively fills course seats but identifies areas for improving student satisfaction. Hypothetical scenarios beyond Dartmouth’s framework, such as indistinct priorities and excess course selections, are also explored, proposing efficient solutions with polynomial time complexity.

This thesis emphasizes fairness in the optimization process, …

Navigating The Complexities Of Ai: The Critical Role Of Interpretability And Explainability In Ensuring Transparency And Trust, Emily Barnes, James Hutson

Faculty Scholarship

The interpretability and explainability of deep neural networks (DNNs) are paramount in artificial intelligence (AI), especially when applied to high-stakes fields such as healthcare, finance, and autonomous driving. The need for this study arises from the growing integration of AI into critical areas where transparency, trust, and ethical decision-making are essential. This paper explores the impact of architectural design choices on DNN interpretability, focusing on how different architectural elements like layer types, network depth, connectivity patterns, and attention mechanisms affect model transparency. Methodologically, the study employs a comprehensive review of case studies and experimental results to analyze the balance between …

Evaluating Methods For Assessing Interpretability Of Deep Neural Networks (Dnns), Emily Barnes, James Hutson

Faculty Scholarship

The interpretability of deep neural networks (DNNs) is a critical focus in artificial intelligence (AI) and machine learning (ML), particularly as these models are increasingly deployed in high-stakes applications such as healthcare, finance, and autonomous systems. In the context of these technologies, interpretability refers to the extent to which a human can understand the cause of a decision made by a model. This article evaluates various methods for assessing the interpretability of DNNs, recognizing the significant challenges posed by their complex and opaque nature. The review encompasses both quantitative metrics and qualitative evaluations, aiming to identify effective strategies that enhance …

Grazing Annual Pastures – Using Feed On Offer (Foo) As A Guide, Department Of Primary Industries And Regional Development, Western Australia

Animal production and livestock factsheets

Grazing management in winter and spring in South West Western Australia (SW WA) can manipulate the quality, quantity and composition of pasture. These pasture changes can increase livestock feed efficiency and productivity, reduce insect populations and improve pasture persistence. Seasonal grazing based on feed on offer (FOO) is described here to maximise stocking rate and pasture production.

The Department of Primary Industries and Regional Development recommends using feed measurements and feed budgeting to increase productivity and reduce livestock health risks.

Boosting Winter Pasture Growth, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Applying gibberellic acid or nitrogen fertiliser to pasture in winter can increase dry matter production of grasses and broadleaf weeds and help reduce feed shortages in winter.

The Cultivation Of Ulva Lactuca In Jambiani, Zanzibar: A Case Study, Jazmine R. Compton

Anthós

This case study explores the feasibility of Ulva lactuca cultivation in Jambiani, Zanzibar, Tanzania. The seaweed farming industry in Zanzibar is facing challenges related to climate change that have resulted in increased rates of crop failure and decreased production. Cultivation of the green algae Ulva lactuca has been suggested as a potential solution due to its tolerance to extreme environmental conditions. In collaboration with Marine Cultures, this project has tested different cultivation methods typically used for red algae (Rhodophyta) species. Experimental plots of Ulva lactuca were established in Jambiani, Zanzibar using the floating line and off- bottom methods. At the …

Towards Faster Inference Of Transformers: Strategies For Accelerating Decoding Processes, Cunxiao Du

Dissertations and Theses Collection (Open Access)

This thesis delves into the acceleration and optimization of Transformer inference, a subject of increasing importance with the emergence of Large Language Models (LLMs). The study primarily addresses the challenges posed by two inherent properties of Transformers during inference: the quadratic complexity of the attention mechanism and the sequential nature of autoregressive inference. The research is structured into three main parts. The first part enhances the learning capabilities of non-autoregressive Transformers, achieving a remarkable 15.0x acceleration on machine translation tasks. The following section focuses on lossless acceleration through speculative decoding, where the proposed algorithm, Glide with CAPE, is shown to …

Auditory Ace Mobile Application Capstone Review, Layla Smith

University Honors Theses

This paper describes the development process and outcomes of my 2023-2024 Capstone Project, Auditory Ace, a self-directed auditory training mobile application for individuals with cochlear implants. Recognizing the limitations of current market offerings, Dr. Timothy Anderson created a Capstone project proposal to develop an accessible auditory training mobile application. The Capstone team that took on this proposal consisted of Darya Haines, Dustin Huynh, Jordan Nguyen, Nihar Koppolu, Scott Thorkelson, Sienna Day, and myself, Layla Smith. This paper is structured to follow the Agile software development methodology, which we used to develop Auditory Ace, reviewing in detail every major choice we …

The Cascading Effects Of Database Design, Liam Mccracken

University Honors Theses

This paper details how a relational database influenced the design of the rest of a software project. The software project in question is WonderTix, an open-source ticketing and donation platform for the use of Portland Playhouse under continuous development by teams of Portland State students as their computer science capstone project. The paper, a capstone review thesis, examines WonderTix as an instantiation of the Model-View-Controller design pattern, noting how the model, a relational database based on the SQL standard, influenced the design of the view and controller components. This influence is explored from three angles. First, when the implementation of …

Wipots: An Application Layer Protocol With Network Protocol Stack Enhancements For Wireless Power Transfer Networks, Muhammad Omer Farooq

Department of Computer Science Publications

Nowadays, a far-field wireless power transfer (WPT) system aims to deliver wireless power over a distance of a few meters. Communication among devices for the purpose of WPT in the far-field WPT system is unique as its purpose is to establish, maintain and monitor a WPT session among devices in the system. For proper functionality of a WPT system, a number of communication-, control- and management-related challenges need to be addressed. Hence, here an application layer protocol specifically designed for a WPT system is presented. The protocol provides essential control, management and communication functionalities to establish, maintain and monitor a …

Settingsorder Article Reprints Open Accesseditor’S Choicearticle Exploring The Impact Of Spray Process Parameters On Graphite Coatings: Morphology, Thickness, And Tribological Properties, Adedoyin Abe, Josue A. Goss, Min Zou

Mechanical Engineering Faculty Publications and Presentations

This study explores, through a full factorial experimental design, the effects of graphite concentration and spray flow rate on the morphology, thickness, and tribological performance of graphite coatings for potential tribological applications. Coatings were applied to rough substrates using varying concentrations and flow rates, followed by analysis of their morphological characteristics, roughness, thickness, coefficient of friction (COF), and wear behavior. The results revealed distinct differences in the coating morphology based on flow rate, with low-flow-rate coatings exhibiting a porous structure and higher roughness, while high-flow-rate coatings displayed denser structures with lower roughness. A COF as low as 0.09 was achieved, …

Qwixx Strategies Using Simulation And Mcmc Methods, Joshua W. Blank

Master's Theses

This study explores optimal strategies for maximizing scores and winning in the popular dice game Qwixx, analyzing both single and multiplayer gameplay scenarios. Through extensive simulations, various strategies were tested and compared, including a scorebased approach that uses a formula tuned by MCMC random walks, and race-to-lock approaches which use absorbing Markov chain qualities of individual score sheet rows to find ways to lock rows as quickly as possible. Results indicate that employing a scorebased strategy, considering gap, count, position, skip, and likelihood scores, significantly improves performance in single player games, while move restrictions based on specific dice roll sums …

Recursive Marix Game Analysis: Optimal, Simplified, And Human Strategies In Brave Rats, William A. Medwid

Master's Theses

Brave Rats is a short game with simple rules, yet establishing a comprehensive strategy is very challenging without extensive computation. After explaining the rules, this paper begins by calculating the optimal strategy by recursively solving each turn’s Minimax strategy. It then provides summary statistics about the complex, branching Minimax solution. Next, we examine six other strategy models and evaluate their performance against each other. These models’ flaws highlight the key elements that contribute to the effectiveness of the Minimax strategy and offer insight into simpler strategies that human players could mimic. Finally, we analyze 123 games of human data collected …

Semantic Structuring Of Digital Documents: Knowledge Graph Generation And Evaluation, Erik E. Luu

Master's Theses

In the era of total digitization of documents, navigating vast and heterogeneous data landscapes presents significant challenges for effective information retrieval, both for humans and digital agents. Traditional methods of knowledge organization often struggle to keep pace with evolving user demands, resulting in suboptimal outcomes such as information overload and disorganized data. This thesis presents a case study on a pipeline that leverages principles from cognitive science, graph theory, and semantic computing to generate semantically organized knowledge graphs. By evaluating a combination of different models, methodologies, and algorithms, the pipeline aims to enhance the organization and retrieval of digital documents. …

Dehn's Problems And Geometric Group Theory, Noelle Labrie

Master's Theses

In 1911, mathematician Max Dehn posed three decision problems for finitely

presented groups that have remained central to the study of combinatorial

group theory. His work provided the foundation for geometric group theory,

which aims to analyze groups using the topological and geometric properties

of the spaces they act on. In this thesis, we study group actions on Cayley

graphs and the Farey tree. We prove that a group has a solvable word problem

if and only if its associated Cayley graph is constructible. Moreover, we prove

that a group is finitely generated if and only if it acts geometrically …

Morp: Monocular Orientation Regression Pipeline, Jacob Gunderson

Master's Theses

Orientation estimation of objects plays a pivotal role in robotics, self-driving cars, and augmented reality. Beyond mere position, accurately determining the orientation of objects is essential for constructing precise models of the physical world. While 2D object detection has made significant strides, the field of orientation estimation still faces several challenges. Our research addresses these hurdles by proposing an efficient pipeline which facilitates rapid creation of labeled training data and enables direct regression of object orientation from a single image. We start by creating a digital twin of a physical object using an iPhone, followed by generating synthetic images using …

Hydrological Analysis Of Post-Fire Responses Within The Little Creek Watershed Of Swanton Pacific Ranch, Alexander Jeffrey Wiens

Master's Theses

Climate change and a growing wildland-urban interface are associated with an increase in the number and severity of wildfires. While severe wildfires do cause a costly and dangerous impact on the environment and the public, their after-effects comprise important subjects of study. In post-fire hydrologic studies, the reduced infiltration and plant cover that results from wildfires can commonly be associated with increased peakflows and erosion. Phenomena such as the flooding and debris flows in Montecito after the Thomas Fire in late 2017 can have important implications on infrastructure and human lives. Quantifying post-fire peak flows and flooding volumes has therefore …

Unraveling The History Of Deforestation In The Amazon Rainforest With Statistical Modeling, Ryan Destefano

Master's Theses

The Amazon rainforest, a vital ecosystem of immense biodiversity and global climate significance, faces the ongoing threat of deforestation driven by agricultural expansion. This thesis employs remote sensing techniques, focusing on the Enhanced Vegetation Index (EVI) derived from Landsat satellite imagery, to track land cover dynamics within the Amazon. The study examines historical land cover changes in current plantations in Peru and Brazil, regions where the exact timing of deforestation is uncertain. By analyzing EVI measurements dating back to 1984, inflection points indicative of deforestation events preceding plantation establishment are identified. Statistical modeling techniques, including spline fitting to analyze time …

Using Plankton Edna To Estimate Whale Abundances Off The California Coast: Data Integration And Statistical Modeling, Katherine Chan

Master's Theses

Understanding marine mammal populations and how they are affected by human activity and ocean conditions is vital, especially in tracking population declines and monitoring endangered species. However, tracking marine mammal populations and their distribution is challenging due to difficulties in observation and costs. Using surrounding plankton environmental DNA (eDNA) has the potential to provide an indirect measure of monitoring cetacean abundances based on ecological associations. This project aims to apply statistical methods to assess the relationship of visual abundances of common species of baleen whales with amplicon sequence variants (ASV) of plankton eDNA samples from the NOAA-CalCOFI Ocean Genomics (NCOG) …

Balancing Darkness And Visibility: An Algorithmic Approach To Light Placement In Low-Light, Ray-Traced Scenes, Briana Kuo

Master's Theses

In recent years, digital media has seen incredible advancements in rendering visually stunning computer graphics scenes. Photo-realistic games, animated films, and more leave viewers blown away by the sheer beauty of their graphics. However, challenges arise when depicting dark scenes, often resulting in visual monotony and difficulty in comprehension due to insufficient detail within the scene. In order to enhance readability and visual interest of a scene, additional, artificial lights can be placed throughout a scene to enhance the aesthetic. These lights, however, must be strategically placed in order to retain an essence of darkness and maintain the delicate balance …

Using Bayesian Multispecies Models To Evaluate Fish And Invertebrate Detection Probability And Distribution In The Hypersaline Bahia Grande Tidal Basin, Roy M. Ulibarri, Catherine M. Eckert, David Hicks, David Montagne, Brandon Jones, David R. Stewart

School of Earth, Environmental, & Marine Sciences Faculty Publications

Objective

In 2000, the Laguna Atascosa National Wildlife Refuge acquired the Bahia Grande (Texas) management unit, a space that had lain barren and arid for 70 years. A large cooperative partnership launched a restoration project to replenish the basin and recover its original tidal hydrology. In 2005, the construction of a pilot channel successfully restored water throughout the basin, and plans to eventually widen the channel were developed. Our study aims to evaluate an estuarine habitat restoration by assessing ecological drivers and the impacts on species diversity.

Methods

We evaluated species richness, detection/occupancy rates, and species–habitat relationships, and we estimated …

Amino-Modified Upcycled Biochar Achieves Selective Chromium Removal In Complex Aqueous Matrices, Kenneth Flores, Diego F. Gonzalez, Helia Magali Morales, Arnulfo Mar, Sergi Garcia-Segura, Jorge L. Gardea-Torresdey, Jason Parsons

School of Earth, Environmental, & Marine Sciences Faculty Publications

Chromium pollution of groundwater sources is a growing global issue, which correlates with various anthropogenic activities. Remediation of both the Cr(VI) and Cr(III), via adsorption technologies, has been championed in recent years due to ease of use, minimal energy requirements, and the potential to serve as a highly sustainable remediation technology. In the present study, a biochar sorbent sourced from pineapple skins, allowed for the upcycling of agricultural waste into water purification technology. The biochar material was chemically modified, through a green amination method, to produce an efficient and selective adsorbent for the removal of both Cr(VI) and Cr(III) from …

Lead Along Arid Route 66: Concentration, Fate, Surface Transport, And Awareness, Dominic Joel Ombati

Loma Linda University Electronic Theses, Dissertations & Projects

Fate and transport of lead (Pb) are well studied in humid, high precipitation environments. Few studies have compared or addressed fate of lead (Pb) in arid, low precipitation areas where the soil binding capacity may differ from classic studies. The goal of this study is to identify the control of fate and transport in the arid section of Route 66 by determining the concentration, chemical forms, and surface transport mechanism of lead (Pb) along the arid section of Route 66. Understanding the fate and transport of lead (Pb) in different environments is key in the environmental mitigation of lead (Pb) …

A New Design Strategy For Sizes Of Polymer Gel Treatments Derived From A Comprehensive Assessment Of Their Case Histories, Munqith Aldhaheri, Abdullah Almansour, Na Zhang, Mingzhen Wei, Baojun Bai

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The incentive to revive brownfield oil production extends the interest to apply polymer gel treatments in injection wells. Virtually, volumes of previous remediations implemented in similar reservoir types are used to size new jobs. Such an analogy-Based design procedure imposes a need to evaluate the most frequent designs for each reservoir type based on a comprehensive field survey. This survey provides a new treatment sizing strategy for polyacrylamide-polymer bulk gels by reviewing their field applications in 653 injection wells. the new strategy proposes using the average and most frequent gel volumes per reservoir type as an initial estimate of the …

Representation Theory And Its Applications In Physics, Max Varverakis

Master's Theses

Representation theory, which encodes the elements of a group as linear operators on a vector space, has far-reaching implications in physics. Fundamental results in quantum physics emerge directly from the representations describing physical symmetries. We first examine the connections between specific representations and the principles of quantum mechanics. Then, we shift our focus to the braid group, which describes the algebraic structure of braids. We apply representations of the braid group to physical systems in order to investigate quasiparticles known as anyons. Finally, we obtain governing equations of anyonic systems to highlight the differences between braiding statistics and conventional Bose-Einstein/Fermi-Dirac …

Modeling The Effect Of Population Size On Banking Transaction Channels In Nigeria: Grey Box Vs Support Vector Regression, Desmond Bartholomew, Ngozi P. Olewuezi, Chrysogonus C. Nwaigwe, Felix C. Akanno

CBN Journal of Applied Statistics (JAS)

This study investigates the effect of Nigeria’s population on four selected banking transaction channels. The Nigerian projected population (2022-2027) was used as an input variable for forecasting future volumes of transactions for each channel. The results show that the Support Vector Regression (SVR) model best fits the ATM, Online, and USSD channels of transaction while the Grey-box was better for POS. The forecast results show that ATM, online, and USSD channels had their highest volume of transactions in 2023, while for POS, the highest volume was recorded in 2027. Further results indicate that online and POS transactions would dominate payment …

Value Added Tax Rate Variation, Import Demand And Sectoral Output In Nigeria, Joshua K. Nomkuha, Aondoawase Asooso, Philip T. Abachi

CBN Journal of Applied Statistics (JAS)

This study employs computable general equilibrium (CGE) model to estimate the effect of increase in value added tax (VAT), from 5 per cent to 7.5 per cent, on import demand and sectoral output in Nigeria. The study uses 2020 as the base year for the data analysis. The results show that increase in VAT affects import demand negatively, based on import penetration ratios, with mixed effect across six sectors. The implication of the result is that the VAT policy discourage consumption of foreign products, and constitute excess burden to consumers of such products in Nigeria. The results further reveal that …

Trade Liberalization, Non-Oil Export And Economic Growth In Nigeria, Jerome T. Andohol, Terhemen Tarzoor, Dennis T. Nomor

CBN Journal of Applied Statistics (JAS)

The study examines the impact of trade liberalization and non-oil exports on economic growth in Nigeria from 1986 to 2021. The study utilizes an autoregressive distributed lag model and found the combined effect of trade liberalization and non-oil exports to be positive and statistical significant. While trade liberalization alone may have negative consequences, its synergy with a robust non-oil export can drive sustainable economic growth. The study recommends that strategies to enhance non-oil exports should be encouraged to support the effectiveness of trade liberalization in promoting growth.

The Effectiveness Of Monetary Policy Transmission In Nigeria: Evidence From The Monetary Policy Rate And The Cash Reserve Ratio, Abdulrahman A. Nadani, Auwal Isah

CBN Journal of Applied Statistics (JAS)

This paper investigates the effectiveness of the Monetary Policy Rate (MPR) and Cash Reserve Ratio (CRR) as policy instruments in Nigeria. A structural VAR model is employed to simulate two distinct models measuring shocks from the MPR and the CRR using monthly data from January 2006 to December 2023. Findings show that contractionary monetary policy impulses using MPR and the CRR contract output and credit to the private sector, inflation remains largely positive in the two models, known as the “price puzzle”, but the puzzle is more persistent in the MPR equation. Moreover, shock to MPR strongly influences short-term interest …