Engineering Commons^™

Scalable Hypergraph Structure Learning With Diverse Smoothness Priors, Benjamin T. Brown

Theses and Dissertations--Electrical and Computer Engineering

In graph signal processing, learning weighted connections between nodes from signals is a fundamental task when the underlying relationships are unknown. With the extension of graphs to hypergraphs, where edges can connect more than two nodes, graph learning methods have similarly been generalized to hypergraphs. However, the absence of a unified framework for calculating total variation has led to divergent definitions of smoothness and, consequently, differing approaches to hyperedge recovery. This challenge is confronted in this work through generalization of several previously proposed hypergraph total variations, allowing ease of substitution into a vector-based optimization. To this end, a novel hypergraph …

Electromagnetic Integral Equation Methods For High-Order Field Predictions, Jordon N. Blackburn

Theses and Dissertations--Electrical and Computer Engineering

Methods like the Method of Moments (MoM) or the locally-corrected Nyström (LCN) method are employed to discretize and solve electromagnetic integral equations. This process results in large, dense systems of linear equations that must be solved. In many cases, the elements of the system matrix can be computed analytically or approximated with high-order numerical methods. In this thesis, various approaches are presented to improve the accuracy and efficiency of integral equation solutions.

The second chapter derives a modified form of the low-rank matrix approximation algorithm known as the adaptive cross approximation (ACA). The original ACA has been observed to lose …

Lifecycle Carbon Footprint And Sustainability Evaluation Of Dram-Based Processing In Memory Computing Architectures, Samrat Pravin Patel

Theses and Dissertations--Electrical and Computer Engineering

The use of computing technologies has significantly enhanced several aspects of our day-to-day lives. But it has still revealed significant environmental concerns, primarily related to greenhouse gas emissions and energy consumption. Initially, the primary environmental problems associated with computing were energy consumption during device operation. However, with the rapid advancement of technology and increasing computational demands, attention has shifted towards the embodied carbon footprint. This term refers to the total greenhouse gas emissions throughout a product’s lifecycle from the extraction of raw materials to end-of-life processing. It has become increasingly significant in the context of manufacturing integrated circuits (ICs), such …

Afapbp: Aggregate Function Accelerated Parallel Bit-Pattern Computing, Charles Z. Armstrong

Theses and Dissertations--Electrical and Computer Engineering

Classical computing models have proven sufficient for problems of the complexity class ``P", but problems of a higher complexity class like ``NP", ``NP-Hard", etc. have been shown to be more resistant to efficient computation. Quantum Computing is an alternative computing model that specifically targets performing computations within the ``NP" complexity class in close to linear time. However, Quantum Computing has its own set of problems. Methods for dealing with quantum decoherence, error correction, and difficulty in scaling have all inhibited Quantum Computing from becoming a commonly used computational model. This thesis introduces AFAPBP (Aggregate Function Accelerated Parallel Bit Pattern), a …

Scalable Systems And Devices For Wireless Charging Of Electric Vehicles, Donovin D. Lewis

Theses and Dissertations--Electrical and Computer Engineering

The rising adoption of electric vehicles creates new opportunities that are not possible with conventional gas-powered vehicles such as wireless charging of electric vehicles (EV). Wide-scale implementation of wireless charging could result in benefits unique to EVs such as operation without human intervention, improved charging accessibility, and even in-route wireless charging for charge-sustaining or extended driving range operation. As the technology is in the early stages of development, there are many open-ended challenges to tackle including but not limited to coil and systems cost, weight and size, stray field emissions in high-power, high-frequency operation, and dynamic wireless charging system design …

Analysis And Design Optimization Of Electric Machines With Field Intensifying Configuration, Ali Mohammadi

Theses and Dissertations--Electrical and Computer Engineering

The design and optimization of electric machines face increasing demands for efficiency, improved torque density, manufacturability, and effective utilization of materials. Meeting these demands is particularly vital in for example, electric vehicles (EVs) and renewable energy systems, where performance, reliability, and cost are critical. In this dissertation innovative field-intensifying electric machine configurations have been explored, emphasizing advanced topologies, computational modeling, and optimization techniques to advance the state of the art in electric machine design and analysis.

Electric machines with high torque density are essential for many low-speed direct-drive systems, such as wind turbines, in-wheel traction, and industrial automation. This dissertation …

Multi-Objective Design Optimization Of Power Converters For Electric Aircraft Propulsion, Ben Luckett

Theses and Dissertations--Electrical and Computer Engineering

As global focus shifts to the electrification of the aviation sector, the need for high efficiency, lightweight, and reliable electric aircraft propulsion power converter systems has become apparent. These goals can be somewhat conflicting with each other, and a single multi-domain-optimized solution is not guaranteed. The search for a design which presents satisfactory merits becomes a drudge through various trade-off studies which can expend vast quantities of manpower and time. As a remedy to this, design automation allows the process to be computer-assisted. This dissertation presents the core fundamentals for a general multi-objective design optimization framework intended for the design …

Predicting Crises On The African Frontier Stock Markets With Investor Sentiment Indicators: A Machine Learning Approach, David Korsah, Lord Mensah

Journal of International Technology and Information Management

This study examined the predictive ability of machine learning algorithms in identifying crises within African stock markets. The study employed seven distinct machine-learning models, analyzing historical stock prices from eight stock markets, three major sentiment indicators, and the exchange rates of local currencies against the US dollar, with each data spanning from May 1, 2007, to April 1, 2023. Extreme Gradient Boosting (XGBoost) emerged as the most effective algorithm for predicting crises. Historical stock prices and exchange rates were identified as the most critical features for prediction. On the sentiment side, investors’ perceptions of potential volatility on the S&P 500, …

A Conceptual View Of Data For Decision-Oriented Databases: A Knowledge-Driven Approach, Sung-Kwan Kim, Wenjun Wang, Seunghyun Kim

Journal of International Technology and Information Management

Typical database design goes through three levels of data modeling: conceptual modeling, logical modeling, and physical modeling. In particular, conceptual modeling is important since it captures and documents user data requirements. Conceptual modeling serves as a blueprint for designing a database by defining information content to be included in a database. Presently, decision-oriented databases have no well-accepted conceptual modeling approach to apply. While some use conceptual modeling approaches for transaction-oriented databases such as the ER (Entity-Relationship) model, they are not well-suited for decision-oriented databases. It is hard to map from the ER Model to decision-oriented data models. Others attempt to …

Preventive Health Care Information Seeking Behaviors Among Baby Boomers In Taiwan, Alexander N. Chen, Michael J. Rubach, Tracy Suter, Hsin Ke Lu, Mark E. Mcmurtrey

Journal of International Technology and Information Management

Preventive health care is widely acknowledged as one of the most effective ways to reduce medical costs and enhance people's health. Preventive health care information (PHCI) is a crucial component. This study examines the PHCI-seeking behaviors of Taiwanese baby boomers. The study found some support for the idea that the preferred media used influenced the likelihood of Information seeking behavior. People with good health conditions were found to be more likely to seek PHCI, while people with greater health care needs sought out PHCI less frequently. The study examined social influences, which were found to be important. Three different types …

Pedagogy In The Age Of Ai: Exploring Generative Ai For Higher Education, Alison Munsch Phd

Journal of International Technology and Information Management

Generative Artificial Intelligence (AI) presents transformative opportunities for higher education, enabling personalized learning, enhanced student engagement, and efficient pedagogical practices. This tutorial-style article guides educators in integrating generative AI into their classrooms through hands-on activities, practical strategies, and reflective exercises. It explores the capabilities of AI tools such as ChatGPT, their applications across disciplines, and the ethical considerations for their use. By cultivating critical thinking and fostering student readiness for AI-driven futures, this article underscores the transformative potential of generative AI in higher education with an emphasis on the academic areas of business analytics, information systems, and computer science.

Surviving And Thriving In The Hybrid Cloud: A Review Of The Current Cloud Computing Landscape, Peter Munsch, Alison Munsch

Journal of International Technology and Information Management

Background and Purpose

Both academic and industry institutions have increasingly migrated essential services to public cloud providers (e.g., Microsoft, AWS, Google) with mixed outcomes. Some industry leaders attempted to fully replace their on-premises data centers with public cloud services, a move not advised without thorough performance and cost analyses (Potel, 2023). Despite some organizations pulling back from the “Cloud First” strategy, the public cloud services market continued to grow, with revenue increasing by approximately 20% year-over-year since 2020 and surpassing half a trillion dollars in 2022 (IDC Worldwide Semiannual Public Cloud Services Tracker, 2H 2022). Cloud technologists suggested that hybrid …

Predicting Global Healthcare Supply Chain Delays: A Machine Learning Approach Leveraging Country-Level Logistics Metrics, Jeevan Sai Gali, Nima Molavi, Sepideh Alavi

Journal of International Technology and Information Management

In global healthcare logistics, ensuring the timely delivery of medical commodities is critical, particularly in low- and middle-income countries characterized by infrastructural limitations and operational uncertainties. This research introduces an advanced, data-driven predictive framework designed to forecast delivery delays by synthesizing granular, internal shipment-level data from the USAID Global Health Supply Chain Program (GHSC-PSM) with external country-level logistics capabilities indicators derived from the World Bank’s Logistics Performance Index (LPI). Rather than relying on retrospective trend analyses, this study employs machine learning algorithms such as Random Forest, XGBoost, Support Vector Machines (SVM), and Multi-Layer Perceptron (MLP) to detect …

Transport Of Nutrients By Overland Flow On Sites Containing Beef Cattle Manure, John E. Gilley, Ryan P. Mcgehee, Kenneth M. Wacha

Department of Agricultural and Biological Systems Engineering: Faculty Publications

In an inductive metastudy, we investigated the effects of varying rates of overland sheet flow on the transport of phosphorus (P) and nitrogen (N) from sites containing beef cattle manure. The analyzed data were collected during previously reported field rainfall simulation investigations conducted on cropland sites and a beef cattle feedlot in the US state of Nebraska. During the experiments, inflow was incrementally added to the top of the experimental plots to simulate runoff rates occurring at greater downslope distances. Runoff rates on the experimental plots ranged from 2.9 to 22.9 Lmin⁻¹, and the maximum equivalent downslope distances …

Crop2cloud Platform: Real-Time Data Integration For Agricultural Water Monitoring, Bryan Nsoh, Abia Katimbo, Kendall Dejonge, Wei-Zhen Liang, Hongzhi N. Guo, Yufeng Ge, Derek M. Heeren, Yeyin Shi, Xin Qiao, Daran R. Rudnick, Hope Njuki Nakabuye, Birru Girma, Isa Kabenge, Joshua Wanyama

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Efficient water management is vital for sustainable agriculture, yet integrating real-time data for precise irrigation remains a challenge. This study designed the Crop2Cloud (C2C) platform, a system that leverages advanced sensors using Internet of Things (IoT), edge and cloud computing techniques, and computed Water Stress Indices (WSIs) and machine learning models (i.e., fuzzy logic), to provide scalable and real-time irrigation decisions. The C2C platform aggregates several data including Volumetric Water Content (VWC) from TDR sensors (Acclima Inc., US) installed at four multiple depths, canopy temperatures (Tc) measured by Infrared Radiometers (IRTs) (Apogee Instruments, US), as well as weather information and …

Behavioral Insights Impacting Preweaning Mortality, Md Towfiqur Rahman, G. A. Rohrer, S. R. Sharma, Y. Shi, S. M. Leonard, Tami M. Brown-Bandl

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Conclusions

This study investigated the average time spent on posture behaviors (lying, kneeling, sitting, standing) of sows by analyzing the effects of time segments, farrowing crate types, parity, heat lamp configurations, and mortality groups. Sow posture behaviors were significantly influenced by mortality, parity, crate type, heat lamps, and day category. High mortality sows spent less time lying and more time standing events. Parity 1, 2, 3 sows were more active, spending more time kneeling in transitions, lying, and sitting events. Sows in TSL crate had longer lateral right lying and standing events, while ESCSL crates sows had longer sitting events. …

Firelog: An Open-Source, Low-Cost System For Temperature Logging During Wildland Fires With High Spatial And Temporal Resolution, Nipuna Chamara, Yufeng Ge, Sabrina E. Russo

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Measuring flame, air, and soil temperatures during wildland fires, including wildfires and controlled burns in land management contexts, is crucial for research and applications in fire ecology, safety, and management in a wide array of ecosystems, from grasslands to forests. However, open-source and commercial systems are needed for measuring and logging flame and air temperatures that are user-friendly, economical, modular, and customizable. This paper details the design, development, and validation of the FireLog system. Laboratory validation experiments demonstrated high measurement accuracy, with a minimum coefficient of determination (R2) of 0.98 and the highest observed root mean square error (RMSE) of …

Highly Sensitive Diffractive Optical Structures For Detection Of Volatile Organic Compounds, Faolan Radford Mcgovern

Doctoral

From aerospace to agriculture, sensors play a fundamental role in many aspects of modern life. Sensors form an integral part of the complex systems and devices required for the continued functioning and development of services and industries across society. The use of sensors is paramount in areas affecting human health, one such area being the monitoring of indoor air quality, in particular the detection of volatile organic compounds (VOCs). Human contact with VOCs has been associated with many health complications, including skin and eye irritation, cardiovascular damage, and cancers. Optical, electrical, gravimetric, and chemical sensors have been developed for VOC …

Cover Crops Can Reduce Greenhouse Gas Emissions From No-Till Maize In Southern Brazil: Insights From A Long-Term Field Experiment, Guilherme Rosa Da Silva, Adam J. Liska, Cimélio Bayer

Adam Liska Papers

Brazil is one of the countries that has the most agricultural area under no-till (NT) management. This research study aims to evaluate life-cycle greenhouse gas (GHG) emissions from maize (M) grain production in agroecosystems that used different cover crops under NT management in southern Brazil. The data for this study were from a long-term 41-year field experiment in southern Brazil. The long-term experiment evaluated the effects of fallow (F) and cover crops (oat (O), vetch (V), cowpea (B), pigeon pea (P), and lablab (L)) on nitrous oxide and methane emissions and soil carbon (C) sequestration in maize agroecosystems. Five cropping …

Inactivation Of Zika Virus With Hydroxypropyl-Beta-Cyclodextrin, Cory R. Hewitt, Nicholas J. Wixon, Arthur Gallegos, You Zhou, Victor C. Huber, M. Scott. Killian

Nebraska Center for Biotechnology: Faculty and Staff Publications

Background/Objectives: Zika virus (ZIKV) infection is associated with life-threatening diseases in humans. To date, there are no available FDA-approved therapies or vaccines for the specific treatment or prevention of ZIKV infection. Variation in the ZIKV envelope protein (Env), along with its complex quaternary structure, presents challenges to synthetic approaches for developing an effective vaccine and broadly neutralizing antibodies (bnAbs). We hypothesized that beta-cyclodextrin (BCD) could be used to uniquely inactivate infectious ZIKV without disruption of Env.

Methods: ZIKV was propagated in Vero cells and admixed with BCD. The BCD-treated ZIKV was evaluated for infectivity using immunofluorescence and quantitative …

Microscopic Analysis Of Temperature Effects On Surface Colonization And Biofilm Morphology Of Salmonella Enterica, Zachariah Vice, You Zhou, Sapna Chitlapilly Dass, Rong Wang

Nebraska Center for Biotechnology: Faculty and Staff Publications

Salmonella enterica represents a diverse group of pathogens commonly associated with food contamination including red meat. Even though pre- and post-harvest cleaning and sanitization procedures are widely implemented at meat processing plants to mitigate the hazard, S. enterica cells may escape the process by colonizing, on contact, surfaces in the form of a biofilm that functions as an aggregated microbial community to facilitate mutual protection, antimicrobial resistance, proliferation and dissemination. Biofilm development is a complex process that can be affected by a variety of factors including environmental temperature. We developed methods using scanning electron microscopy and confocal microscopy with a …

Characterization Of Multispecies Microbial Communities At Beef And Pork Processing Plants And Their Impact On Pathogen Stress Tolerance, Rong Wang, Sapna Chitlapilly Dass, Vignesh Palanisamy, You Zhou, Tatum Katz, Joseph M. Bosilevac

Nebraska Center for Biotechnology: Faculty and Staff Publications

Escherichia coli O157:H7 and Salmonella enterica are major foodborne pathogens. Biofilm formation may potentially contribute to product contamination by these pathogens at meat processing facilities. Further, pathogen stress tolerance may vary significantly due to the interactions with the multispecies microbial community at meat plants, which may be affected by processing activity, animal species, and the local selective pressure caused by sanitization practices.

We characterized natural microorganisms collected from floor drains at various areas at three beef plants and two pork plants and analyzed their impact on pathogen sanitizer tolerance.

The pathogen strains were able to integrate efficiently into the multispecies …

Extending Revised Lewis Gear Root Bending Stress Model To Addendum Modified Cylindrical Gears, Edward E. Osakue

Faculty Publications

This paper presents a new revised Lewis gear bending root stress model for both standard profile and profile-shifted cylindrical gears. The three parameters that are used to extend the root bending stress capacity of standard profile gears to profile-shifted gears are the profile shift radius factor, the profile shift load factor, and the modified Lewis stress factor. These three parameters are functions of the profile shift factor. The new bending capacity model is used to estimate the bending stresses for some standard profile gears with nominal helix angles between 0o to 41.41o and compared with estimates of AGMA model. The …

Designing An Affordable Motion Capture System For Multi-Robot Research And Education, Hojune Kim , '25

Senior Theses, Projects, and Awards

In this work, we propose a low-cost motion capture system for real-time tracking of multiple robots’ positions and orientations in indoor environments, specifically tailored for research and educational applications. Precise localization is essential for evaluating robotics algorithms such as decentralized multi-agent control, cooperative path planning, and collision avoidance. [1-3] However, commercial motion capture systems like Vicon and OptiTrack cost between $50,000 and $150,000, making them inaccessible for many smaller institutions, student clubs, and low-resource labs. To address this challenge, we developed an affordable alternative based on three ceiling-mounted 1080p USB cameras and AprilTags. Our system operates at 30 Hz and …

Frost Heave Physical Simulation Testing Apparatus, Noah Edgar , '25

Senior Theses, Projects, and Awards

The uplift forces exerted on lightly loaded pile foundations through the heaving stresses developed in freezing soils can have a significant impact on the design and cost of the foundations for utility scale solar generation facilities. Since the adfreeze stress that exerts the uplift force is highly dependent on the soil type, a one-size fits all approach to this frost heaving behavior is ineffective. To solve this issue, a testing apparatus was designed that can be repeatedly used to more accurately determine the heaving stresses that will develop given a specific soil type. The testing apparatus uses the soil collected …

A Bevel Gear Root Bending Stress Model, Edward E. Osakue, Rasoul Saneifard

Faculty Publications

A reversed Lewis root bending stress capacity model for bevel gears is presented. The model is developed from first principle based on the Tredgold’s approximation of a bevel gear. The approximation conceptually transforms a bevel gear into a spur gear. The load distribution of the bevel gear facewidth is assumed to be triangular so that the stress at the gear is constant over the facewidth. Six design cases of root bending stress computations from different references are done using the new and AGMA models. The stress estimates from the new and AGMA models were compared. The stress deviations associated with …

Investigations Of Conjugate Heat Transfer And Fluid Flow In Partitioned Porous Cavity Using Darcy-Forchheimer Model: Finite Element-Based Computations, Nasir Yasin, Shafee Ahmad, Muhammad Umair, Zahir Shah, Narcisa Vrinceanu, Ghadah Alhawael

Mathematics & Statistics Faculty Publications

The conjugate heat transfer and fluid flow has vast applications in thermal engineering, particularly for cooling in thermal devices, and automobile engines. This study investigates conjugate heat transfer in 2D enclosures, featuring thin solid fins attached to a porous bottom wall. The porous medium is considered isotropic and homogeneous by the Darcy-Forchheimer model, with fluid phases in local thermal equilibrium. The boundary conditions at the porous fluid interface ensure continuity of the velocities, stresses, temperature, and heat flux. The phenomenon is mathematically modelled by obtaining a set of partial differential equations. The finite element method (FEM) is used to perform …

Effect Of Manufacturing Process On Mechanical Properties Of Polyetheretherketone (Peek) Cranial Implants Produced By Single-Point Incremental Forming (Spif), Elizabeth M. Mamros, Ihab Ragai, Brian Young

Faculty Conference Papers and Presentations

Polyetheretherketone (PEEK) is one of the most commonly used materials for cranioplasty due to its biocompatibility, relatively high strength, and light weight. Cranial implants manufactured from PEEK sheets using the same manufacturing process, e.g., single point incremental forming (SPIF), will have differing part properties based on the selected polymer forming process. Three fabrication methods for PEEK sheets were investigated: extrusion, modified hot pressing, and injection molding. Material characterization specimens were extracted for tensile, impact, and differential scanning calorimetry (DSC) experiments. The PEEK sheets were also subjected to formability tests at room temperature using SPIF. Slight differences in ultimate tensile strength …

Investigation Using Single Point Incremental Forming (Spif) To Fabricate Patient-Specific, Titanium Orbital Floor Implants, Elizabeth M. Mamros, Lauren E. Blaha Md, Christian A. Kauffman Md

Faculty Conference Papers and Presentations

The floor of the human orbit is composed of thin bone that is prone to traumatic fracture. This leads to a loss of support for the eye, which can cause vision changes. Therefore, fractures may need surgical reconstruction using a thin, sheet-like implant. Titanium implants are available off-the-shelf in standard sizes, but fitting to each patient’s unique anatomy requires surgeons to cut, file, and bend these plates. This can be time-consuming and imprecise. To both save time and ensure a perfect fit for the patient, a custom plate can be created prior to surgery. This investigation focuses on single-point incremental …

Scalable Machine Learning Framework For Adaptive Irrigation Management Of Maize And Soybean In The U.S. Midwest, Precious N. Amori, Derek M. Heeren, Yeyin Shi, Eric Wilkening, Ivo Z. Goncalves, Guillermo R. Balboa, Daran R. Rudnick, Abia Katimbo, Randall S. Ritzema

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Conventional soil water balance (SWB) irrigation scheduling tools, such as FAO-56-based Spreadsheets and the Spatial Evapotranspiration Modeling Interface (SETMI), rely heavily on manual inputs and periodic field measurements, leading to delayed recommendations and missed opportunities to prevent crop stress. More critically, these tools lack the computational scalability and adaptability to leverage the high-frequency, high-volume datasets now available through modern sensing technologies. As precision irrigation increasingly depends on integrating spatially and temporally nuanced field information, there is a pressing need for decision-support systems that can process Big Data efficiently and respond in real-time. To overcome these limitations, we developed and validated …