Digital Commons Network^™

Public Perceptions Of Leadership Effectiveness In Ethiopia Over The Last Decade, Fikadu Reta Alemayehu

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

Ethiopia is one of the largest countries in Africa, with a fast-growing economy, rich history, diverse agroecology, more than 70 languages, and a population exceeding 130 million. However, the country continues to face serious internal conflict, high malnutrition, and economic hardship, while the study of leadership effectiveness remains limited and lacks consistent longitudinal research. To help fill this gap, this study examined how public perceptions of leadership effectiveness and development outcomes changed in Ethiopia between 2013 and 2023, using Afrobarometer survey data. The analysis explored how citizens’ views about governance, wellbeing, and access to services evolved during a decade of …

Residential Hvac Installation Faults: Field Prevalence, Drivers, And Energy Impacts, Seyed Ali Rooholghodos

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

Faults in residential comfort systems can have detrimental effects on the performance of the system, reducing the energy efficiency, affecting indoor comfort, and shortening equipment lifespan. Many of the faults occur at installation. However, there has not previously been a systematic and nationally representative study to indicate the prevalence of the faults, meaning the distribution of faults by fault type and fault intensity. Understanding true fault prevalence is essential to be able to identify derivers, and to assess the incremental electricity consumption of the new installation systems.

This study presents on-site data from 341 new central cooling systems—air conditioners and …

Investigating Preservice Elementary Teachers’ Stem Teaching Self-Efficacy And Goal Orientation, Derek Scott Cox

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

In the context of teacher education, self-efficacy and goal orientation can have an impact on one’s motivation, desire to improve, and maintaining a growth mindset in teachers. This study utilized an explanatory mixed methods design to investigate how and why preservice elementary science, technology, engineering, and mathematics (STEM) teachers’ confidence and views on competency changes after completing an array of courses built around integrated STEM.

Sixty-five preservice teachers participated in the pre- post-test quantitative data collection to determine changes in integrated STEM self-efficacy and achievement goal orientations (mastery-approach, mastery-avoidance, performance-approach, performance-avoidance). Data collection measures include Self-Efficacy for Teaching Integrated STEM …

Large-Scale Experimental Study On The Impact Of Air Cleaning & Ventilation On Indoor Air Quality And Student Illness-Related Absenteeism, Daud Nosham

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

This large-scale randomized experimental field study investigated the effect of portable air purifiers (PAPs) on classroom’s air quality and student’s illness related absenteeism. PAPs were installed in 317 classrooms from various school districts located in Eastern Nebraska. The classrooms were randomly assigned into four conditions: three treatment conditions (T1, T2 & T3) and one control condition (device without any filter). T1 was equipped with HEPA filters, T2 added Activated Carbon (AC) layer to HEPA, and T3 further integrated Germicidal Ultraviolet (GUV) alongside HEPA and AC filters. The measured variables were carbon dioxide (CO2), fine particles (PN2.5) and coarse particles (PNcoarse), …

Resources For The Beginning And Intermediate Jazz Educator: Reviews Of Modern Resources And Implementation In The Classroom, Bryan Canonigo

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

This document is a compilation and discussion of different modern jazz education resources geared towards beginning and intermediate students. It is intended for the younger high school jazz educator who may have just started their careers and are searching for new(er) resources to aid their teaching and rehearsal techniques. For the seasoned high school jazz educator, this document may suggest additions to their current lesson plans and/or updates to their current resource compilations and rehearsal practices. A primary goal of this document is to suggest ideas to aid these educators in teaching jazz music more wholistically, in small or large …

Detecting Prescribed Fire, Haying And Grazing Events Via Remote Sensing To Create Grassland Disturbance Landcovers For The Ring-Necked Pheasant (Phasianus Colchicus), Megan A. Baldissara

School of Natural Resources: Dissertations, Theses, and Student Research

This dissertation developed disturbance detection models to fulfill the need for remote sensing landcover products describing grassland structure. The use of landcover products derived from remote sensing is increasing over time in pheasant (Phasianus colchicus) research. Such landcover, however, does not provide relevant pheasant structural habitat information (Chapter 1). Pheasants require tall, high-density grassland for nesting, tall grassland with medium density for brood rearing, and tall grassland for wintering. Time since disturbance can serve as a proxy for structure, as it shapes vegetation by removing biomass and resetting succession. Disturbance is easier to detect than structure with current …

On Bayesian Empirical Likelihood-Based Method For Complex Survey Data With Application To Non-Probability Sampling, Md Hasibur Rahman

Department of Statistics: Dissertations, Theses, and Student Research

This thesis develops a Bayesian empirical likelihood (BEL) framework for inference under complex survey designs and extends it to non-probability sampling. Parametric likelihood based methods are difficult to apply to complex survey data because the likelihood is rarely available in closed form. EL provides a flexible alternative by replacing the parametric likelihood with an empirical likelihood constructed from moment conditions. The proposed method first integrates empirical likelihood constraints with survey design features then extends BEL to non-probability sampling through selection models and design consistent restrictions. Posterior inference is carried out using a Metropolis–Hastings MCMC algorithm. A real-data analysis further illustrates …

Brands & Virtual Personas: How Virtual Influencer Types Impact Brand Awareness, Carol Calderon Ambelis

Department of Textiles, Merchandising and Fashion Design: Dissertations, Theses, and Student Research

As social media continues to shape how consumers interact with brands, virtual influencers (VIs) have emerged as a new type of digital celebrity. While previous research has explored how VIs contribute to brand image and awareness, there has been limited attention on how different types of VIs, both anime-like and human-like, affect consumer perceptions across different markets. This study examines how these two types of VIs impact relatability, aspiration, and brand awareness, with a focus on the differences between luxury and mass market. Using a within-subjects experimental design, this study recruited 574 participants with social media experience using MTurk. The …

Modeling The Greenland-Iceland-Faroe Ridge Using Integrated Geophysical Analysis, Zachary Clowdus

Department of Earth and Atmospheric Sciences: Dissertations, Theses, and Student Research

The Greenland-Iceland-Faroe Ridge (GIFR) is an area of significant geologic interest with anomalously thick crust related to enhanced melt generation from the interaction between the Mid-Atlantic Ridge and the Iceland hotspot. To the northeast of Iceland lies the Jan Mayen Microcontinent (JMMC), which is a continental fragment separated from Greenland during the opening of the Northern Atlantic. The overall extent of the JMMC, especially its southern boundary, remains poorly constrained. The crust beneath the GIFR is believed to be primarily of oceanic affinity. However, a recent discovery of felsic lavas in Iceland led to an alternative hypothesis that implies the …

The Role Of Peroxisomal Acot4 And Acot8 In Modulating Lipid Metabolism And Stress Pathways In Steatotic Hepatocytes, Sylwia Miekus

Department of Nutrition and Health Sciences: Dissertations, Theses, and Student Research

Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by excessive lipid accumulation in hepatocytes and the development of lipotoxic stress that disrupts cellular homeostasis. Peroxisomal lipid metabolism plays an important role in maintaining acyl-CoA balance during fatty acid overload, yet the contribution of peroxisomal acyl-CoA thioesterases to early lipotoxic responses remains insufficiently understood. The aim of this study was to investigate the functional involvement of the peroxisomal enzymes acyl-CoA thioesterase 4 (ACOT4) and acyl-CoA thioesterase 8 (ACOT8) in hepatocyte lipid handling under acute lipotoxic conditions. An in vitro model of steatosis was established in AML12 cells through exposure to a …

Llm-Assisted Cwe Identification, Severity Assessment, And Vulnerability Description Generation, Mohammad Jalili Torkamani

School of Computing: Dissertations, Theses, and Student Research

Identifying the underlying weakness types and assessing their severity using CWE and CVSS standards are critical steps in software vulnerability management. While timely assessment of vulnerabilities mitigates the impact of severe security incidents, automating joint CWE identification and severity assessment remains challenging due to the heterogeneity of vulnerabilities across different code granularities and programming languages. In addition, generating vulnerability descriptions is often time-consuming, as it requires extensive manual review, validation, and writing by security experts.

In this thesis, we leverage the capabilities of Large Language Models (LLMs) to automate the identification of CWE identifiers and the assessment of their severity …

Evaluating Metamitron Efficacy For Glyphosate-Resistant Palmer Amaranth (Amaranthus Palmeri) Management In Sugarbeet Across The Central High Plains, Abraham Akuoko

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Herbicide-resistant (HR) Palmer amaranth (Amaranthus palmeri S. Watson) is regarded as one of the most prominent weeds within sugarbeet fields across the Central High Plains, with limited chemical control options. Although a few herbicides are available, their use is restrictive due to crop injury concerns and can only be applied at or after the 2–4 true leaf (TL) growth stage, which will provide no control for already emerged weeds. However, Palmer amaranth often emerges between sugarbeet planting and the 2 TL sugarbeet growth stage. Consequently, as of 2023, there were no herbicide options to control Palmer amaranth in sugarbeet …

Fragmentation In The U. S. Fed Cattle Market: Implications For Price Transparency And Discovery, Taralee M. Hudson

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

The U.S. fed cattle market is one plagued by recurring stakeholder concern. Market participants frequently raise questions about the transparency of fundamental information under existing reporting frameworks, and the extent to which Private Negotiation, the dominant trading institution, effectively facilitates price discovery. Although extensive research has sought to address these issues, much of it has failed to account for the market’s increasingly fragmented structure. This thesis is comprised of three chapters that collectively examine price transparency and discovery through the lens of market fragmentation. Each chapter presents research related to the fed cattle market and is intended to stand …

Developing A Metabolic Engineering Chassis From A Metabolically Versatile Organism, Rhodopseudomonas Palustris Cga009, Mark William Kathol

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

Metabolic engineering has made it possible to develop biological processes that were once considered economically unfeasible or uncompetitive. This field has enabled both a robust niche market, whereby products, such as pharmaceutical substances like monoclonal antibodies, are produced exclusively through biological means, as well as an emerging commodity production market. Nonetheless, significant challenges remain in harnessing the unique metabolic capabilities of genetically non-tractable organisms. This dissertation focuses on Rhodopseudomonas palustris CGA009 as a potential chassis for metabolic engineering. To address the issue of genetic intractability, a synthetic biology toolkit was developed to facilitate the expression of heterologous proteins in R …

Characterization Of Mitochondrial Dna Repair Components And Repair Choices At Targeted Double-Strand Breaks In Arabidopsis Thaliana, Moira Rodriguez

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

Plant mitochondrial genomes are complex when compared to most other eukaryotic mitochondrial genomes. They are large and variable in size, expand and rearrange frequently, abundant in non-tandem repeats, but maintain a very low synonymous substitution rate in the remaining coding regions. Many of these complexities can be explained by the increased use of double-strand break repair for DNA damage. To advance the understanding of mitochondrial genome dynamics as it relates to double-strand break repair, we performed a forward genetics screen to identify proteins involved in DNA repair in plant mitochondrial genomes. Through this screen, we identified an RNA/DNA helicase, Suv3, …

Reinforcement Learning Based Security Schemes For Distributed Ai Systems, Ashan Chamath Gunawardena

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

Distributed machine learning (DML) is a component of modern intelligent systems, enabling collaborative training across devices such as mobile clients, vehicles, and edge networks. However, the decentralized nature of these systems introduces vulnerabilities, particularly data poisoning attacks that compromise model integrity and degrade performance. Traditional defenses, such as statistical filtering, robust aggregation, and privacy-preserving techniques, often struggle to adapt to overwhelming adversaries or operate under strict privacy and real-time constraints. This dissertation proposes the use of reinforcement learning (RL) and deep reinforcement learning (DRL) based misbehavior detection schemes that dynamically identify poisoning attempts in distributed AI systems, including federated learning, …

Investigating Programming Behaviors To Understand Student Engagement And Experience In Introductory Programming Courses, Marcus Eugene Gubanyi

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

Introductory programming courses are foundational to developing students’ problem-solving abilities and shaping their persistence in computing pathways. Engagement with programming tasks plays a central role in student learning and experience. Many research measures, including self-reports and code submissions, offer only a limited view of student engagement with programming tasks. This dissertation leverages programming process data, consisting of keystrokes and compilation events, to capture the programming process as it unfolds and to investigate observable programming behaviors. Guided by educational theories, three studies examine how students’ programming behaviors vary across instructional and assessment contexts, how they relate to motivational profiles, and how …

Ethical Decision-Making Processes In Authentic Environmental Engineering Contexts Through Systems Thinking And Team Collaboration Lenses: An Embedded Single Case Study, Toluwalase Eniola Brower

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

Ethical and professional responsibility is a critical learning outcome emphasized in ABET accreditation. However, ethics instruction in engineering education often lacks integration of system-level considerations such as economic, environmental, and societal contexts, that are essential for developing engineering solutions that ensure the safety and welfare of diverse stakeholders. This embedded single-case study investigated the integration of authentic ethics instruction within a junior-level environmental engineering course at a Midwestern U.S. university during spring 2025 and explores how civil engineering student teams within the course engage in ethical decision-making process during authentic problem-solving.

The instructional intervention consisted of four problem-based ethics modules, …

Changepoint Detection As Model Selection: A General Framework, Michael A. Grantham

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

This dissertation presents a general framework for changepoint detection based on ℓ₀ model selection. The core method, Iteratively Reweighted Fused Lasso (IRFL), improves upon the generalized lasso by adaptively reweighting penalties to enhance support recovery and minimize criteria such as the Bayesian Information Criterion (BIC). The approach allows for flexible modeling of seasonal patterns, linear and quadratic trends, and autoregressive dependence in the presence of changepoints.

Simulation studies demonstrate that IRFL achieves accurate changepoint detection across a wide range of challenging scenarios, including those involving nuisance factors such as trends, seasonal patterns, and serially correlated errors. The framework is …

The Motivation And Influence Behind The Decisions Of High School Students To Participate In The National Ffa Organization, Taylor A. Nielsen

Department of Agricultural Leadership, Education, and Communication: Dissertations, Theses, and Student Research

Today, high school students are increasingly engaged in extracurricular activities, navigating a diverse range of options for which clubs and organizations to join during their secondary education. This poses a challenge for students and for Career and Technical Student Organizations as they work to recruit talented students. High school students have several influences and pressures on their time, including peers, family, and teachers. These influences often recognize how organizations such as FFA can be pivotal in shaping students’ personal and professional development. We wanted to explore the motivations and influences guiding high school students’ decisions to join and actively participate …

Rapid State-Of-Health Estimation Of Batteries Using Machine Learning With Limited Eearly-Discharge Voltage Data, Mohammad Bakhtiari

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

The utilization of lithium-ion batteries has been rapidly expanding across diverse sectors, including electric transportation, stationary energy storage systems, and the built environment. Ensuring a high level of reliability in these applications is essential, as the performance and safety of such systems depend strongly on the accurate assessment of the battery’s State of Health (SOH). Conventional SOH estimation techniques—often based on complex electrochemical models or extensive laboratory testing—tend to require a large number of measurements, advanced instrumentation, and high computational cost. These factors make them impractical for large-scale deployment or real-time monitoring. This study introduces a simplified machine-learning-based approach for …

The Graphic Shift: Leveraging Superhero Graphica To Un-Ban Critical Conversations In The Secondary English Language Arts Classroom, Avery Clason

Department of English: Dissertations, Theses, and Student Research

This thesis investigates the challenges that books are receiving during an era of social and political turmoil based on their content. Understanding why these books are polarizing for most readers and the general public is in direct connection with finding different books that can harbor the same conversations about dense topics and cultivating connections between students, the text, the world, and themselves. While there has been a search to find alternate books that are not considered "political flashpoints,” there has been limited research into the use of superhero graphica in the ELA classroom, especially in connection to utilizing this genre …

A Strategic Audit Of Live Nation Entertainment: Industry Position, Competitive Dynamics, And Long-Term Growth Outlook, William H. Wooden Iv, Owen B. Crone, Reece L. Flores, Grace A. Schaefer, Eric M. Jacob, Sydney A. Beck

Honors Program: Senior Projects (Public)

Live Nation Entertainment is the dominant global leader in the concert and live events industry, supported by a vertically integrated model that spans artist management, concert promotion, venue operations, ticketing, and sponsorship. This strategic audit evaluates Live Nation’s internal strengths, external threats, competitive position, corporate governance, and long-term strategic prospects based on comprehensive analysis of company reports, industry dynamics, and market trends. Live Nation benefits from unmatched scale, global venue ownership, exclusive artist relationships, and the substantial network effects generated by Ticketmaster, which collectively create high barriers to entry and sustained competitive advantage. The audit also examines significant challenges such …

Integrating Innovative Sensing And Ground Measurements For Forage Mass Estimation In Rye Pasture, Pedro Henrique Jota Fernandes

Department of Animal Science: Dissertations, Theses, and Student Research

The United States beef industry relies on forages to provide up to 80% of total lifetime dry matter intake, making accurate forage mass estimation essential for determining stocking rates, improving grazing efficiency, and supporting economic sustainability. Traditional methods to quantify forage mass, however, are time-consuming and labor-intensive. This thesis presents research efforts to achieve accurate forage mass estimation in cereal rye pasture by integrating novel sensing technologies.

Chapter 1 reviews the importance and evolution of forage mass estimation methods, from destructive clipping to indirect approaches based on canopy measurements. It then introduces remote sensing, from proximal tools to drone- and …

Communication And Privacy Management Between Female Veterans, Their Military Voluntary Kin, And Biolegal Family Members, Carol Lee Tschampl-Diesing

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

Military voluntary kin (MVK) refer to relationships between Service members and/or Veterans that they consider to be “like family,” despite lacking blood or legal ties. The purpose of this qualitative/interpretive communication study was to explore how female Veterans, who are the largest growing population of U.S. Veterans, discursively construct MVK relationships, navigate communication, privacy management, and boundary turbulence with their MVK and biolegal families (BLF). The researcher undertook in-depth interviews with nine female U.S. Veterans who reported having at least one MVK. The researcher posed four research questions, engaging in an interpretive analysis.

Participants described three ways they navigated interactions …

Occurrence Of Per And Polyfluoroalkyl Substances In Rural Wastewater Treatment Plants And Comparison To Large Treatments Plants, Madeleine Rauhauser

Department of Civil and Environmental Engineering: Dissertations, Theses, and Student Research

Per and polyfluoroalkyl substances (PFAS) are a class of compounds defined by their carbon – fluorine bonds, which are incredibly strong. The strength of this bond makes these compounds very useful industrially, they are used as waterproof and grease proof coatings, and as fire retardants. The same thing that makes them useful industrially makes them incredibly recalcitrant in the environment, it is difficult to destroy these compounds. PFAS are also suspected to cause health impacts in people, such as kidney cancer and low birth weights. Wastewater has been commonly identified as a contributor to the amount of PFAS in the …

Further Evaluation Of Speed Tables On Roadway Curves: Simulation And Expeditionary Deployments, Nathan Reineke

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The road network leading up to a United States military base is known as an Entry Control Facility, or ECF. Entry control facilities are used to shield military installations by monitoring vehicles and refusing access to unauthorized vehicles. Passive control devices, including speed tables, are used to disrupt or delay threat vehicles attempting to navigate ECFs at high speeds. The purpose of this research was to recommend optimized configurations of speed tables in combination with roadway curves which allow safe, efficient traversal for authorized vehicles and disruption or delay for threat vehicles.

First, an analytical model of a Tesla Model …

Musical Self-Efficacy Through Active Music Listening: A Phenomenological Approach, Amy Marie Fraser

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

Music is often perceived as a talent reserved for the naturally gifted, rather than a fundamental human ability. This study questioned that perception by examining how active music listening can develop musical self-efficacy and reshape attribution beliefs about musical ability. Using a phenomenological approach, this study explored the experiences of students in a university music appreciation course, investigating how structured listening exercises, peer interactions, and reflections contribute to their perceived musical beliefs and competence. Grounded in Bandura’s self-efficacy theory and Weiner’s attribution theory, the study considered whether musical engagement can be accessible to all and not limited by perceived talent. …

Two Essays On Agricultural Trade Policy And Total Factor Productivity, Hanifi Otgun

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

This dissertation consists of two essays: the first examines the welfare and trade implications of the 2016–2017 drought in Brazil and the subsequent temporary import ban on Robusta coffee; the second examines how trade openness influences agricultural total factor productivity across 26 NUTS-2 regions in Türkiye from 2013 to 2020.

The first essay focuses on Brazil, a major Robusta coffee producer and exporter that faced a significant drought in 2016–17, reducing Robusta output. In response, the government initially allowed one million 60-kg bags of Robusta coffee to be imported. An import ban was imposed shortly afterward due to lobbying by …

Defending The Homeland: An Archaeoethnodemographic (Aed) Analysis Of Population Dynamics And Settlement Patterns In The Navajo Dinétah, Ad 1720–1745, Kurt Mantonya

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

This dissertation presents an innovative archaeoethnodemographic (AED) analysis of Navajo population dynamics during the Middle Period (AD 1720−1745) of the Gobernador Phase in the Dinétah, the ancestral Navajo homeland in northwest New Mexico. During this critical quarter-century, intensified Ute and Comanche slave-raiding and Spanish military expeditions forced the Diné to abandon traditional dispersed settlement patterns in favor of defensive aggregation around fortified pueblitos—small masonry defensive structures built on boulder-tops and mesa-rims throughout the region.

The study employs an AED framework that systematically integrates archaeological site analysis, ethnographic household organization data, historical documentation, and demographic modeling to reconstruct population dynamics during …