Physical Sciences and Mathematics Commons^™

Knighted Pawn's Tour, Morgan Wilson

Honors Theses

The Knighted Pawn’s Tour is a variant of the traditional Knight’s Tour problem, whichitself is an instance of the Hamiltonian cycle problem. The deviation from the Knight’s Tour problem is that a pawn begins on any field on the second rank (row), and advances with legal moves that can include captures to the opposite end of the board to become a knight. These fields, used by the pawn on the path to knighthood, are subsequently forbidden for the knight’s return to the starting field. The knight must traverse the rest of the chessboard, visiting each remaining field exactly once …

Synthetic Efforts Towards An Analog Of Ly426965, Macy Sproles

Honors Theses

The 5-hydroxytryptamine_1A (5-HT_1A) receptor is a key target in the treatment of various neuropsychiatric conditions, and the development of selective antagonists offers promising therapeutic potential.²⁴ This study aimed to develop a synthetic analog of LY426965, a selective 5-HT_1A receptor antagonist. The synthetic route was initiated from dimethyl-2-phenylmalonate, employing pig liver esterase (PLE) as an enantioselective biocatalyst to achieve regioselective hydrolysis of one ester moiety in the malonic diester intermediate.¹⁷ Through a series of stereochemically controlled transformations, a new intermediate was successfully synthesized. Although the target molecule was not obtained, a new compound was synthesized …

Joint Modelling Of Longitudinal Egfr Trajectory And Time To Acute Kidney Injury In Lung Transplant Patients, Samiha Zakir

Theses and Dissertations

Progressive declines in estimated glomerular filtration rate (eGFR) often precede acute kidney injury (AKI), yet the relationship between eGFR trends and AKI risk remains unclear. This study investigates longitudinal eGFR changes and their association with AKI in 459 lung transplant patients followed for up to 7 years (n = 6419). We applied a piecewise linear mixed-effects model to evaluate eGFR trajectories and a Cox proportional hazards model to assess time to AKI. A joint model was used to explore the interplay between longitudinal and survival processes. Key covariates included gender, age at transplantation, antibody-mediated rejection (AMR), and pre-transplant eGFR. Males …

Effects Of Reflective Journaling And Nudges On Academic Motivation And Engagement, Lakshmi Satya Sai Veda Mahita Uppuluri

Theses and Dissertations

This study investigates the effects of reflective journaling and motivational nudges on academic motivation and engagement among college students. Grounded in Self- Determination Theory (SDT), the research examines how different interventions influence intrinsic motivation, and academic behaviors such as class attendance, participation, and preparation. The study employed a between-group experimental design with three conditions: a control group, a journaling group, and a journaling group that also received daily motivational nudges. Results showed that students in the journaling groups—particularly those who received nudges—experienced a significant increase in academic motivation. While changes in academic engagement were not significant, the effect size suggested …

Stochastic Analysis With Operational Calculus In Reliability, Hend Hamdan Al-Jahani

Theses and Dissertations

Our dissertation models several reliability systems subject to occasional random shocks of random magnitudes W1,W2,..occurring at times tau0, tau2,..In Model 1, the underlying system becomes inoperational if it wears out due to aging specified by a monotone increasing continuous function Delta identifying system's wear at any time t>=0 . The system is deemed inoperational if delta crosses a sustainability threshold at some moment T=(delta )^-1(D). The precise time T is difficult to identify making the realistic failure time randomly delayed and thus identified at some opportune observation epoch. The system can also fail due to damages by external shocks, …

An Analysis Of Face Morphing Presentation Attacks Against Facial Recognition Systems, Joshua Breininger

Theses and Dissertations

Security has been a problem for human society for as long as history has been recorded. The identification of people is an ongoing, ancient battle, with a variety of methods that only become more complex with time. The Romans performed censuses, ciphers have been used for thousands of years in the pursuit of security, and in modern day we own identifications and governments keep track of who lives in their country with citizenship and licenses. The question of ”Who are you?” is vital for society to function, which opens up a massive field of potential for how to ask that …

Expressive And Interpretable User Engagement Prediction Using Multivariate Survival Processes, Akshay Aravamudan

Theses and Dissertations

The ability to characterize how information diffuses online is of paramount importance to stakeholders that are interested in tasks such as proposing solutions for mitigating and countering dis/misinformation, predicting user engagement of content in social media, planning marketing campaigns to roll-out products and planning dissemination of political campaign messaging among others. One such facet of learning the dynamics of information diffusion is the ability to predict user engagement or the popularity of a single piece of information as it spreads through an online medium. Existing works in this regard mainly either obfuscate user level information or utilize frameworks that are …

Hello Again! Llm-Powered Personalized Agent For Long-Term Dialogue, Hao Li, Chenghao Yang, An Zhang, Yang Deng, Xiang Wang, Tat-Seng Chua

Research Collection School Of Computing and Information Systems

Open-domain dialogue systems have seen remarkable advancements with the development of large language models (LLMs). Nonetheless, most existing dialogue systems predominantly focus on brief single-session interactions, neglecting the real-world demands for long-term companionship and personalized interactions with chatbots. Crucial to addressing this real-world need are event summary and persona management, which enable reasoning for appropriate long-term dialogue responses. Recent progress in the human-like cognitive and reasoning capabilities of LLMs suggests that LLM-based agents could significantly enhance automated perception, decision-making, and problem-solving. In response to this potential, we introduce a model-agnostic framework, the Long-term Dialogue Agent (LD-Agent), which incorporates three independently …

Decoding The Algorithm: The Mathematics Behind Tiktok’S Short-Form Content Success, Ashley N. Lynch

Honors Scholar Theses

Within the realm of social networks, TikTok has become the central hub for short-form video content. The network’s unique ability to capture individual preferences using predictive analytics has greatly contributed to its massive success, allowing the company to optimize its performance and content personalization. In an age where digital media have such a significant influence on society, it is essential that users develop an understanding of how social network algorithms function to make more informed online decisions. Although TikTok’s technological system is primarily undisclosed, the platform certifiably leverages several key mathematical principles within its algorithm to achieve its core goals …

Small Scale Magnetohydrodynamic Thruster, Samuel Rabaey

Celebrating Scholarship and Creativity Day (2018-)

This paper explores the performance of a self-constructed, small-scale magnetohydrodynamic (MHD) thruster using saltwater as the conductive fluid. The MHD drive generates propulsion through Lorentz force by applying an electric current across electrodes in the presence of an orthogonal magnetic field. Two experiments were conducted: one measuring static water displacement to determine force output, and another using fluid velocity in a closed loop to evaluate both force and efficiency at varying magnetic field strengths. Theoretical predictions based on MHD and fluid dynamics principles were compared with experimental results. While the measured outputs were consistently lower than theoretical approximations, likely due …

Fluorescence Lifetime Of Bulk Cadmium Sulfide Excited By Two-Photon Absorption, Grady Schierts

Celebrating Scholarship and Creativity Day (2018-)

An attempt was made to measure the fluorescence lifetime of bulk cadmium sulfide excited by two-photon absorption. The excitation source was an 800-nm unamplified Ti:sapphire laser that produced 50-fs pulses at a repetition rate of 82 MHz. An acousto-optic modulator (AOM) driven by a waveform generator was used as a pulse-picking device. A sufficiently fast AOM could pick a single pulse from the pulse train to excite the cadmium sulfide. Due to limitations on the speed of the available AOM, it was not possible to pick a single pulse. Instead, packets with a minimum of three pulses could be picked …

Synthesis, Characterization, And Redox Properties Of Select 1,4-Diazocine-6,11-Diones Towards An Electrochromic Dye-Set, Jeffrey Scott Richards

Open Access Theses & Dissertations

The daily consumption of personalized digital visual information depends on the current purview of electronic-based displays. Present manufacturers utilize modern technologies, such as LCD, OLED, QLED, and electronic ink, or "E Ink," in their devices to display text, pictures, and other forms of media to individual users. However, as modern society continues to rely on the use of digital displays, the demand for low-power alternatives will continue to rise as their application in varying scenarios is realized. Currently, "E Ink" technology continues to grow as the dominant solution in the e-readers and digital signage marketplace, and can even be seen …

From Basel (1989) To Busan (2024): Developments And Contradictions In The Global Plastic Waste Trade, Megan E. Hughes

Honors Theses

In 1989, the international community convened in Basel to adopt groundbreaking, legally binding legislation on the transboundary movement of hazardous waste. Plastic waste was notably absent from the initial Basel Convention due to the perceived economic value in plastic recycling despite social, economic, and environmental harms. Consequently, the transboundary sale of plastic waste for recycling– known as the Global Plastic Waste Trade (GPWT)– has proceeded largely unregulated, enabling unsustainable plastic consumption while exacerbating environmental justice divides between developed and developing nations. Recent commitments in the GPWT, such as the European Commission Circular Economy Action Plan (2015), China’s National Sword policy …

Exploring Educational Affordances Of Interactive Murals, Alyshia Bustos

Computer Science ETDs

Interactive murals are a new technology that blend traditional mural painting and embedded electronics. My work contrasts traditional STEAM projects by introducing youth to programming, building electronics, and interaction design principles within the context of designing and constructing interactive murals. Accordingly my dissertation addresses the following: 1) How can we integrate traditional mural practices and ubiquitous computing in an interactive mural, 2) How do interactive murals support youth in learning how to program and build electronics, and 3) How can we design learning activities that support youth as interaction designers?

To address my research questions, I first conducted technical tests …

Evaluating Risk And Return Of Corn And Soybean Marketing Strategies Using Monte Carlo Simulation Methods, Johanna Ilves

Department of Agricultural Economics: Dissertations, Theses, and Student Research

This study evaluates the performance of pre-harvest marketing strategies for corn and soybeans, using Monte Carlo simulation techniques. Given the increasing volatility in commodity prices and the evolving landscape of agricultural markets, producers face growing challenges in developing effective marketing plans that manage risk and enhance profitability. This thesis examines thirteen marketing strategies from 2008 to 2024, including benchmark harvest-only sales and various pre-harvest futures contract approaches. Historical futures price data for December corn and November soybean contracts were used to simulate 1,000 marketing outcomes per strategy per year, capturing a broad range of market conditions. Key performance indicators such …

Walleye And Sauger Movement And Entrainment In Lewis And Clark Lake, William Joseph Radigan

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Walleye Sander vitreus and Sauger Sander canadensis are both socioeconomically important sportfish species in Lewis and Clark Lake, an interjurisdictionally managed mainstem Missouri River reservoir fishery. Since 2011, adult catch per unit effort (CPUE) of both Walleye and Sauger has remained at approximately 50% of pre-2011 levels. A presumed reason for the suppressed CPUE of adult Walleye and Sauger is substantial entrainment of larval and adult fish resulting from the reservoir’s high turnover rate (7.2 d). Acoustic telemetry was used to quantify adult movement and entrainment and ichthyoplankton trawls were used to assess larval entrainment. Relative importance of factors driving …

Physics Embedded Neural Network: A Novel Data-Free Numerical Method For Solving Computational Physics Problems, Pawan Gaire

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

A novel approach for solving partial differential equations (PDEs) using neural networks for scientific computing is introduced. The proposed approach, referred to as physics-embedded neural network (PENN), features a unique architecture that incorporates the PDE and boundary conditions information directly within the final fully-connected layer of the feed-forward neural network (NN). The key aspect of PENN is the parallel numerical embedding of a differential equation associated with physical problems within the activation function of the network’s final layer. This integration leads to a new class of computational solvers competitive with classical methods like the Finite Element Method (FEM) and capable …

Landscape Effects On The Beneficial Arthropod Community In Agriculturally Dominated Environments, Hannah E. Stowe

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Ecosystem services in agriculturally dominated regions rely, at least in part, on arthropods. Environment and biodiversity influence beneficial arthropods in population size, community structure, diversity, and ecosystem service provisioning. Predation is among the most important services provided by arthropods in agroecosystems. Understanding what alters predation and predator activity can support the successful application of biological control and, more broadly, integrated pest management. Land use and edge adjacency, field characteristics, landscape, seasonality, and diel period all alter predatory behavior. Crop fields dominate Nebraska agroecosystems, although interspersed perennial grasslands persist through the Conservation Reserve Program (CRP). Such grasslands supply crucial resources and …

Optimizing Nitrogen Management: Assessing Nitrate Transport In The Deep Vadose Zone And Its Impact On Groundwater Quality In East-Central Nebraska, Muili O. Lawal

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

Groundwater contamination by nitrate (NO₃-N) is a growing environmental and public health concern driven largely by intensive agricultural fertilizer applications. The vadose zone plays an important role in NO₃-N transport, influencing groundwater quality and agricultural sustainability. This study investigated NO₃-N leaching dynamics in the deep vadose zone of Water Quality Sub-Area 30 (WQA30) within the Lower Loup Natural Resources District (LLNRD), northeast of Columbus, Nebraska (mean groundwater NO₃-N: 20.3 mg/L), using soil cores from 16 shallow (to 6.1 m) and four deep (down to 25.9 m) across four zones, two with inorganic fertilizer (Zones 1 and 4) and two with …

Using Permutation Groups To Identify Families Of Capacity Achieving Codes, Daniel Welchons

Department of Mathematics: Dissertations, Theses, and Student Research

When communicating over a noisy channel, the probability of message interference sets a maximum possible transmission rate known as the channel capacity. Any family of codes which have rates converging to the channel capacity and arbitrarily low probability of decoding failure is called capacity achieving. Such codes have been known to exist since the birth of information theory, but are difficult to find explicitly. It has recently been shown that the permutation groups of a family of codes can be used to show that the family is capacity achieving on the q-ary erasure channel.

This thesis seeks to apply the …

Constructing An Attractive Targeted Sugar Bait For Reducing Mosquito Populations, Xi Xian Ng

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Mosquito-borne pathogen transmission continues to pose a significant burden to global public health, well-being, and economic productivity. In the absence of universally available vaccines and amidst rising insecticide resistance that leads to product failures, there is an urgent need to develop new tools to mitigate mosquito-borne disease risk. Two general strategies exist to reduce transmission risk: personal protective measures and area-wide chemical interventions. Attractive Targeted Sugar Bait (ATSB) systems leverage the sugar-feeding behavior of mosquitoes—critical for sustaining their flight, metabolism, development, and fecundity—by delivering oral toxicants through attractively formulated sugar baits. This study aimed to develop an optimized ATSB formulation …

Modeling Degradation In Li-Ion Batteries: Analyzing Single-Cell Degradation And Applying It To Customized Pack-Level, Mohannad Y. Alkhalil

Durham School of Architectural Engineering and Construction: Dissertations, Theses, and Student Research

The rapid expansion of lithium-ion (Li-ion) battery applications in areas such as electric vehicles (EVs), renewable energy storage, and portable electronics has drawn attention to the need for improving their performance, safety, and longevity. As Li-ion batteries become essential across technologies, understanding degradation mechanisms is critical for optimizing design and ensuring reliable operation. This work provides a detailed overview of modeling degradation in Li-ion batteries, focusing on single-cell behavior and its implications for pack-level performance.

The PyBaMM (Python Battery Mathematical Modeling) package, an open-source battery simulation tool written in Python, is used for single-cell simulations. Liionpack, another Python-based library, is …

Rotation Errors Due To Field Quantization For Simultaneously Driven Atoms, Hunter Lindemann

Graduate Theses and Dissertations

If we want to physically implement qubits by using two level atoms within a cavity, then certain single-qubit gates (such as the X-gate) can be performed by bathing the atoms in an electromagnetic field from a laser. If the average photon count n̄ of the field greatly exceeds the number of N qubits, then the slight fluctuations of the field's phase and amplitude are mostly negligible. However, such a strong field might require more energy than what is desirable for the setup. If a weaker field is used in which phase and amplitude fluctuations might be noticeable, then the …

Advancing Snow Water Equivalent Monitoring With Machine Learning And L-Band Interferometric Synthetic Aperture Radar (Insar) Data, Ibrahim Olalekan Alabi

Boise State University Theses and Dissertations

Seasonal snow is a critical freshwater resource for an estimated 2 billion people worldwide. Yet, accurately measuring the amount of water sitting in a snowpack, referred to as snow water equivalent (SWE), over large, often mountainous regions has posed a long-standing challenge. Ground-based measurements of SWE are precise but sparse, while remote sensing techniques like passive microwave sensors struggle with coarse resolution and signal saturation in deep snow. Due to the challenges of direct SWE measurement, snow depth has emerged as an alternative pathway to SWE estimation. SWE is strongly correlated with snow depth, and by leveraging this relationship, we …

5g Network Slice Vulnerabilities And Exploit Chaining Through Enablers, John Breeden

Electronic Theses and Dissertations

Network slicing provides fundamental support for the enhanced features of 5G. Network slicing enablers, such as software-defined networking and network function virtualization facilitate the separation of the physical distributed infrastructures and the functions that create isolated slices. With this framework, the network slice is no longer under the control of a single entity. Multiple infrastructure providers share responsibility for the slice. The 5G architecture derives from multiple services, distributed over great distances, and managed by multiple parties. Each enabler and provider adds vulnerability to network slicing. We examine the interweaving of these enablers to identify vulnerabilities, discuss potential mitigation, and …

Flow Field Surrounding Bluegill (Lepomis Macrochirus) During Suction-Feeding, Jensine Caroline Coggin

Electronic Theses and Dissertations

Suction-feeding is a common method for capturing prey by aquatic organisms and contributed to the diversification of fishes by enabling them to consume a wide range of prey. Suction-feeding is a complex fish-fluid interaction governed by various hydrodynamic forces: inertia, unsteady, viscous, and pressure gradients. These forces are described by the coupling between the flow physics equations (Navier-Stokes) and the dynamic behavior of the fish (motion and forces). However, the distribution of the pressure field that drives this process, and the extent to which suction-feeding is three-dimensional, remain underexplored. I estimated the pressure within the flow field surrounding the mouth …

Modules Of Finite Projective Dimension And Singularities, Nawaj Kc

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

In the first part of this thesis, we study liftings of modules of finite projective dimension. We introduce a notion of “Serre liftable” modules and deduce applications to multiplicity conjectures in local algebra. In the second part, we introduce and study a module of mixed K\"ahler differentials for finite algebras over ramified discrete valuation rings of mixed characteristic. We state and prove a Jacobian criterion for computing the singular loci of such algebras.

Advisors: Jack Jeffries and Mark Walker

Using Permutation Groups To Identify Family Of Capacity Achieving Codes, Daniel Joseph Welchons

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

When communicating over a noisy channel, the probability of message interference sets a maximum possible transmission rate known as the channel capacity. Any family of codes which have rates converging to the channel capacity and arbitrarily low probability of decoding failure is called capacity achieving. Such codes have been known to exist since the birth of information theory but are difficult to find explicitly. It has recently been shown that the permutation groups of a family of codes can be used to show that the family is capacity achieving on the q-ary erasure channel.

This this thesis seeks to …

Ediacaran Paleocommunity Structure, Body Size Evolution, And The Rise Of Complex Animals, Matthew Philip Craffey

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The Ediacaran period (635-538ma) is a key interval in the evolution of life as it records the first macroscopic animal communities. Major extinction pulses appear to have altered the composition of the global marine biosphere between each sub-interval of the Ediacaran Period: the Avalon, White Sea, and Nama assemblage Zones. While considerable attention has been paid to the causes of these extinction pulses, less has been afforded to the consequences of Ediacaran biotic turnover for community organization and function. Moreover, it is unclear how body size - the defining trait of macrofauna - affected the transition between animal groups across …

A Study Of Ultrafast, Intense-Field Photodynamics In Carbon Dioxide, Carbon Disulfide, And Select Substituted Benzenes, Joshua Edwin Beck

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The study of the photodynamics of molecules in ultrashort pulses of intense radiation continues to be of interest. Electric field strengths in such pulses can approach or exceed the typical electric field strengths binding the electrons to the nuclear framework (ke/a²₀ ≈ 5 × 10⁹ V/cm). The resulting excitation, ionization, and dissociation of molecular targets is of interest in many areas including attosecond science, femtochemistry, atmospheric science, high harmonic generation, and many other fields.

This dissertation investigates the photoionization and photofragmentation behavior of carbon dioxide, carbon disulfide, and the substituted benzenes nitrobenzene, aniline, as …