Engineering Commons^™

On Time-Series Analysis By Structured Matrix Decompositions With Applications To Signal Direction-Of-Arrival Estimation, Georgios Ierotheos Orfanidis

Electronic Theses and Dissertations

Modern autonomous systems operating in highly dynamic, non-stationary environments require reliable inference from short, potentially corrupted time-series measurements, where conventional statistical methods relying on large-sample support and stationarity assumptions become fundamentally inapplicable. This dissertation develops a unified, model-free theoretical framework for time-series analysis, with a particular application to signal Direction-of-Arrival (DoA) estimation, grounded in structured matrix decompositions under both the L2-norm and L1-norm formulations.

We first approach the problem from a conventional viewpoint by carrying out standard matrix analysis directly on Hankel-structured representations of time-series data. In this context, we demonstrate that L1-norm decompositions of Hankel matrices offer strong resistance …

Computer Vision And Deep Learning-Based Decision Support System Using Eye Motion Tracking For Nystagmus Detection, Kowshik Balasubramanian

Electronic Theses and Dissertations

This thesis presents the design, implementation, and experimental validation of an artificial intelligence (AI)-driven system for detecting and quantifying nystagmus an involuntary, rhythmic oscillation of the eyes intended as a portable, low-cost complement to conventional Videonystagmography (VNG). The complete pipeline integrates six algorithmic stages: face landmark detection, contrast enhancement, background-aware pixel thresholding, grid-based vertical column filtering, connected-component cluster analysis, and centroid computation, operating in real time on standard smartphone video to extract a sub-pixel normalized iris position time-series without any specialized eye-tracking hardware or infrared illumination. The system supports diagnostic decision-making, highlighting its promise for incorporation into telemedicine settings. The …

Influence Of Web Thickness And Concrete Cover On The Fire Resistance Of Aashto Type Iv Prestressed Concrete Bridge Girders, Fnu Nidhi

Electronic Theses and Dissertations

Bridge fires caused by vehicle accidents, fuel tanker explosions and storage of combustible material beneath highway structures have led to severe structural damage and catastrophic collapse of prestressed concrete bridges. Critical structural collapse due to fire incidents such as I-85 prestressed concrete bridge girder collapse in Atlanta, 2017 and I-95 steel plate girder bridge partial collapse in Philadelphia, 2023 demonstrated the vulnerability of girders when exposed to extreme hydrocarbon fire temperatures exceeding 1000°C within few minutes. These events highlight the urgent need to better understand the thermal and structural behavior of bridge girders and explore design modifications that can enhance …

A Comparative Study Of Tin Electrorefining In Molten Licl–Kcl–Cacl₂: Experimental Two-Electrode Current Control And Theoretical Three-Electrode Potential Control, Bryant Johnson, George Ankrah, Ander Fuller, Devin Rappleye

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

Molten salt electrorefining is a mature technology for metal recovery, yet conventional current‑controlled, two‑electrode operation provides limited electrochemical selectivity and restricted insight into electrode‑specific behavior. In this work, a simplified model is developed to compare current‑controlled two‑electrode electrorefining data with a potential‑controlled three‑electrode electrorefining simulation using tin in molten LiCl–KCl–CaCl₂ as a surrogate for plutonium processing. The model examines anodic and cathodic limitations under fixed‑potential operation and evaluates implications for selectivity, efficiency, and runtime relative to experimentally demonstrated two‑electrode performance. Results indicate that independent potential control enables operation closer to thermodynamic selectivity limits, with the potential to suppress impurity oxidation …

Evaluation Of Quantification Methods Applied To Overlapping Ftir Features, Benjamin P. Diehl

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

Quantifying overlapping FTIR spectral features is critical for electrochemical analysis but often requires complex deconvolution. This work systematically evaluates several area ratio and proxy-based quantification methods using a controlled synthetic spectral model with varying signal-to-noise ratio, peak spacing, width, background, and data resolution. Constrained peak fitting and fixed-window integration consistently exhibit near-perfect monotonicity (Spearman ≈ 1.000) and linearity (Pearson ≈ 0.999–1.000) across all conditions. In contrast, derivative and moment-based metrics show sensitivity to peak overlap, width, and background. These results demonstrate that physically grounded area-based methods provide the most robust and reliable quantification of overlapping FTIR features.

Critical Arteries: Prioritizing Economic Vitality And Emergency Access In Local Networks, Jeremy Hunter

Local Transportation Asset Management Conference

Standard Asset Management Plans (AMPs) often rely heavily on Pavement Condition Index, Paser ratings, and Bridge Condition Ratings to dictate repair schedules. However, a strictly condition-based approach may neglect the economic and safety criticality of specific routes. This presentation proposes a multi-variable evaluation framework for counties, cities, and towns. I will explore methods for overlaying industrial data—specifically for heavy-haul sectors like logging, masonry, and agriculture—to identify and fortify the "economic lifelines" that sustain local revenue. Furthermore, I will address the necessity of resiliency planning within the AMP. By integrating hydraulic data and flood-prone area mapping, agencies can ensure that routes …

Passenger Autonomy In Airport Systems: Integrating Accessibility, Spatial Design, And Technology To Improve Operational Efficiency, John Michael Schmitz

Honors Projects

Airports are among the most complex operational environments in modern transportation, requiring the coordination of passenger movement, security processes, and infrastructure under significant time constraints. Although there have been many advancements in aviation, most passengers continue to experience high levels of stress and confusion while trying to navigate airport terminals. This paper argues that operational efficiency in airport systems is achieved by increasing  passenger autonomy through the utilization of accessible design, spatial legibility, and new emerging technologies. This paper takes note of some foundational theories that drove urban design and cognitive psychology, including Lynch’s concept of imageability, Passini’s theory of …

Water Velocity And Discharge From Tidal Freshwater Creeks In Forested And Herbaceous Wetlands, Austin S. Hudson, G. Curtis Roegner, Gary E. Johnson, David A. Jay

Civil and Environmental Engineering Faculty Publications and Presentations

Acoustic Doppler Current Profilers were deployed in four tidal creeks within forested swamps and herbaceous marshes in the lower Columbia River. Measurements were collected over 12 to 20-day periods during high and low river stage, and then analyzed using wavelet tidal analysis software (CWT_Multi) to characterize temporal variability of water elevation, velocity, and discharge. While subject to similar fluvial and tidal forcing, nuances in creek geometry led to large differences in their hydraulic response. Most obviously, creeks in the higher elevation forested swamps were hydraulically isolated, which limited subtidal discharge but increased tidal monthly variability of discharge in comparison to …

Open Multi-Agent Systems: The Free-Range-Zoo Framework And Moasei Competition, Ceferino J. Patino Iv

School of Computing: Dissertations, Theses, and Student Research

The field of multi-agent reinforcement learning (MARL) has made significant strides in addressing sequential decision-making problems under uncertainty. However, traditional MARL frameworks assume closed-world settings with fixed agent sets, static task distributions, and unchanging environment dynamics. This thesis presents two complementary contributions that advance the state of open-world multi-agent systems research: (1) the free-range-zoo framework, an open-source environment suite for MARL in open environments featuring dynamic agent populations, evolving task sets, and changing operational frames; and (2) the MOASEI Competition, an international benchmarking event that leverages free-range-zoo to evaluate how artificial agents handle openness in complex, partially observable domains. The …

External Force Control Of Transitional And Turbulent Flows, Cesar Alberto Leos

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

Turbulence in wall-bounded flows governs momentum transport, drag, and energy efficiency in a wide range of engineering systems, yet its response to external forcing remains incompletely understood across transitional and high Reynolds number regimes. This dissertation investigates an active flow control strategy based on spanwise external forcing and demonstrates how it modifies the dynamics of transitional and turbulent channel flows with the objective of identifying the mechanisms through which forcing alters transition, flow physics, and turbulent drag reduction.

Firstly, direct numerical simulations are performed to examine the subcritical transition under external forcing. The onset and sustenance of turbulence are shown …

A Machine Learning Framework For Ddos Attack Detection In Sdn-Enabled Mobile Wireless Networks, Ishita Sharma, Satyam Agarwai, Shashi Shekhar Jha, Sumit Chakravarty

Faculty Articles

Attacks on network components and devices pose a significant threat to service continuity, necessitating robust detection mechanisms. This paper presents a Distributed Denial of Service (DDoS) attack detection framework tailored for heterogeneous mobile wireless networks within a Software-Defined Networking architecture. A two-tier model is proposed: localized attack detection at access points (APs) using a Multi-Layer Perceptron (MLP) classifier, and centralized detection under mobility at the controller using a Long Short-Term Memory (LSTM) model. The system incorporates novel traffic features such as flow count, speed of source IP, source and destination IP address entropy, proportion of bidirectional flows, and handover frequency, …

Ai-Driven Detection Of Failure Modes In Thermoplastic Composites Using Acoustic Emission Techniques, M. M. Shahzamanian, Li Ai, Paul Ziehl

Civil Engineering Faculty Publications

Composite materials in aircraft structures can suffer impact damage that leaves barely visible yet structurally significant defects, which degrade mechanical performance, especially under compressive loads. Existing methods for identifying failure modes in compression after impact (CAI) tests using acoustic emission (AE) data are limited in accuracy and scope. This study introduces an approach combining AE sensing with a heterogeneous ensemble convolutional neural network (CNN) to detect and classify failure mechanisms in impacted composite specimens. The novelty of this work lies in employing Red, Green, and Blue (RGB) wavelet images, produced through continuous wavelet transform (CWT) of AE signals, as inputs …

Integrated Approaches For Valorization Of Chicken Feather Waste: From Extraction To Application Of Keratin-Based Bioproducts, Muhammad Ehtasham Akram

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

This dissertation explores the optimization of chicken feathers keratin hydrolysate (CFKH) production using alkaline hydrolysis (AH) and sub-critical water hydrolysis (SCWH), focusing on acquiring high keratin yield in the hydrolysate. Then, CFKH along with other locally sourced materials, was used to develop bioplastics with regenerative agriculture properties (BioWRAP), with the ultimate objective of applying it as a soil mulch to suppress weeds in agricultural crops. This work also addresses challenges in process design and industrial scale-up of BioWRAP. Chapter 1 is a literature review that introduces terms like biobased, biodegradable, and bioplastics, materials and methods used to make bioplastics, and …

Vacuum Modification Of The Surface Properties Of T15k6 Hard Alloy By Plasma–Chemical Synthesis Of Tin-Cu Coatings, Aleksandr Semenov, Dmitriy Tsyrenov, Nikolay Ulakhanov, Irina Semenova, Undrakh Mishigdorzhiyn, Wen Ma, Simon C. Tung, George E. Totten

Mechanical and Materials Engineering Faculty Publications and Presentations

The design and main parameters of a plasma–chemical reactor containing two compartments are presented. One compartment houses a vacuum-arc evaporator, while the other houses a planar magnetron. The compartments are separated by a diaphragm with a dosing slot for injecting copper vapor into the TiN synthesis compartment. The conditions for the synthesis of superhard TiN-Cu composite coatings are experimentally determined. Based on established process parameters for TiN synthesis in a nitrogen-containing plasma by Ti evaporation using a vacuum-arc discharge, it is proposed to apply TiN-Cu coatings by injecting Cu vapor into the TiN synthesis area and sputtering Cu using a …

Extraction And Interpretation Of Eeg Features For Diagnosis And Severity Prediction Of Ad And Ftd Using Deep Learning, Tuan Vo

Electronic Theses and Dissertations

Alzheimer’s disease (AD) is the most common form of dementia and is characterized by progressive cognitive decline and memory impairment. Frontotemporal dementia (FTD), the second most prevalent form, primarily affects the frontal and temporal lobes and often leads to changes in personality, behavior, and language. Due to overlapping clinical symptoms, FTD is frequently misdiagnosed as AD. Electroencephalography (EEG) offers a portable, non-invasive, and cost-effective method for studying brain activity; however, its diagnostic utility for differentiating dementia subtypes is limited by signal complexity and noise. In this dissertation, I propose an EEG-based feature extraction framework that leverages deep learning to identify …

Modified Anodic Stripping Voltammetry For In Situ Analysis Of Liquid Metal Composition In Molten Salt Electrorefining Systems, James H. Manner

Reviews, Analyses, and Instructional Studies in Electrochemistry (RAISE)

The development of in-situ analytical techniques for high-temperature molten salt systems is critical for advancing electrorefining in nuclear fuel recycling and metallurgical purification. This study proposes Modified Anodic Stripping Voltammetry (MASV), using a “dip-and-strip” approach where a tungsten electrode captures molten Sn–Ni alloy before stripping in LiCl–KCl–CaCl₂ at 415 °C. OCP results showed rapid loss of the metal layer due to poor wetting, and stripping peaks gave compositions inconsistent with the alloy, likely reflecting Sn/Sn²⁺ and Sn²⁺/Sn⁴⁺ redox processes. These results highlight interfacial limitations and the need for improved electrode materials and surface modification.

A Machine Learning Framework For Ddos Attack Detection In Sdn-Enabled Mobile Wireless Networks, Ishita Sharma, Satyam Agarwal, Shashi Shekhar Jha, Sumit Chakravarty

Faculty Articles

Attacks on network components and devices pose a significant threat to service continuity, necessitating robust detection mechanisms. This paper presents a Distributed Denial of Service (DDoS) attack detection framework tailored for heterogeneous mobile wireless networks within a Software-Defined Networking architecture. A two-tier model is proposed: localized attack detection at access points (APs) using a Multi-Layer Perceptron (MLP) classifier, and centralized detection under mobility at the controller using a Long Short-Term Memory (LSTM) model. The system incorporates novel traffic features such as flow count, speed of source IP, source and destination IP address entropy, proportion of bidirectional flows, and handover frequency, …

An Evaluation Of Total Navicular Implants: A Scoping Review, James Mcclure Hughes, Nicholas Belardo Obias, Amanda Killeen

School of Podiatric Medicine - Student Research

The aim of this study is to determine the efficacy and safety profile of total navicular implants based on current literature.

Navicular insults such as high-energy trauma, osteonecrosis, and Muller-Weiss syndrome may result in avascular necrosis or a critical sized bone defect, conditions that are highly difficult to manage given current treatment modalities. Total navicular implants may offer a solution to these problems. While 3D printing of implants remains investigational, its use in highly individualized cases involving the talus has had promising results with conditions like avascular necrosis, tumors, trauma, and arthritis. The navicular is unique in its attachments to …

Sdn Controller For Distributed Quantum Computing, Firas Selmi

Masters Theses

Quantum networks promise transformative capabilities for computation [1], but current hardware remains limited; state-of-the-art quantum processors still operate with only a few hundred qubits [2], far below the scale required for practical applications. This limitation motivates the use of Distributed Quantum Computing (DQC), where computation is performed across multiple interconnected nodes. However, efficient DQC requires global network awareness and orchestration, a role analogous to Software-Defined Networking (SDN) in classical systems. In this work, we investigate the impact of SDN-inspired control logic on quantum networks by executing a scaled distributed implementation of Shor’s algorithm to factor N = 15 over a …

2026 - The Thirtieth Annual Symposium Of Student Scholars

Symposium of Student Scholars Program Books

The full program book from the 30th Annual Symposium of Student Scholars, held on April 22-24, 2026. Includes abstracts from the presentations and posters.

Strategic Layout And Optimization Paths Of The Standard System For The Exploration And Exploitation Of Deep Coalbed Methane, Chen Xinjun, Liu Zengqin, Shen Baojian, Zhao Shihu, Ye Jincheng, Zhang Jiaqi, Wang Tianyun

Coal Geology & Exploration

Objective In China, the deep coalbed methane (CBM) industry has emerged as a key sector for the reserve growth and production addition of natural gas. However, the current CBM technical standard system, which was developed based on shallow CBM practices, is incompatible with the demands for the exploration and development of deep CBM. To address this challenge, this study proposes the optimization paths of the current standard system, aiming to provide standardization support for large-scale exploitation of deep CBM.Methods Deep CBM reservoirs exhibit complex geological conditions of high temperature, pressure, and in-situ stress, as well as the CBM occurrence …

Parameter Optimization And Field Application Of Roof Volume Fracturing Using Horizontal Wells For Coalbed Methane Extraction From Broken-Soft Coal Seams, Zhang Qingli, Sun Siqing, Li Haozhe, Wu Xiaoxuan, Yang Fan, Zheng Yuqi, Li Wenbo

Coal Geology & Exploration

Objective and Method To achieve rapid coalbed methane (CBM) extraction from broken-soft coal seams using surface horizontal wells, this study proposed a volume fracturing technology for coal seam roof using horizontal wells. Focusing coal seam 4-1 in a mining area, this study established a numerical model using finite element analysis (FEA) software Abaqus Using this model, the impacts of in-situ stress on the cross-layer propagation characteristics of multiple fractures were investigated. Through true triaxial hydraulic fracturing experiments, the multi-fracture propagation patterns under varying injection rates of fracturing fluids, perforation cluster numbers, and cluster spacings were analyzed. Using 3D fracturing design …

Structural Design And Parameter Optimization Of A Vibration Absorber For Rescue Casing-While-Drilling Rigs, Liu Pu, Yao Ningping, Zou Zujie, Fan Dong, Wei Hongchao, He Binjie

Coal Geology & Exploration

Objective Rescue drilling rigs undergo intense vibration at borehole mouths when operating in a confined underground space of coal mines. To address this issue, this study designed a compact multi-directional, passive dynamic vibration absorber, aiming to improve the operational stability and safety of the rigs. Methods Based on the spring-mass-damping system theory, a stepwise optimization design method was proposed for the longitudinal and transverse dynamic models of the vibration absorber. For the longitudinal vibration model, the particle swarm optimization (PSO) algorithm was applied for multi-objective parameter optimization. In contrast, for the transverse vibration model, the fixed point theory was employed …

Exploring The Vertical Heterogeneity Of Extremely Thick Aquifers In Coal Mines Through Layered Fine-Scale Pumping Tests, Guo Xiaoming

Coal Geology & Exploration

Objective Extremely thick aquifers in mining areas typically exhibit strong heterogeneity and high water yield. Therefore, they are prone to cause severe water inflow in mines and induce water disasters, representing a major factor affecting the mining safety of numerous mines in China. However, the vertical heterogeneity of these aquifers remains poorly understood, emerging as a primary bottleneck in the prevention and control of such water hazards. Methods To scientifically reveal the vertical heterogeneity characteristics of extremely thick aquifers, this study investigated the extremely thick Luohe Formation aquifer in a coal seam roof of a representative coal mine in the …

Optical Mechanisms Behind Vitrinite Reflectance Suppression Caused By Strong Anisotropy: A Case Study Of Contact Metamorphic Coals, An Yanfei, He Shuyang, Chen Kaixin, Gao Junhan

Coal Geology & Exploration

Objective For vitrinite with weak anisotropy, which proves uniaxial and optically negative, replacing random vitrinite reflectance (R_ran) with the maximum vitrinite reflectance (R_max) allows for the accurate correction of vitrinite reflectance suppression induced by anisotropy. However, as its anisotropy intensifies, vitrinite exhibits increasingly complex optical properties, rendering it challenging to reflect the thermal metamorphic temperature of vitrinite using R_max. Methods This study investigated the strongly anisotropic vitrinite in coals and natural coke subjected to magma intrusion in the Shitai coal mine, Huaibei City, Anhui Province. Using a reflected-polarized light microscope (R-PLM), an …

Mechanisms Behind Thermal Evolution Of The Structural Alignment Of Polycyclic Aromatic Hydrocarbons In Coals: Implications For Structural Transition Of Coal Macromolecules, Song Yu, Jiang Bo, Cheng Guoxi, Zheng Sijian, Li Ming, Ge Yao, Dai Yan, Wang Qian, Feng Guangjun

Coal Geology & Exploration

Objective Coals are highly sensitive to variations in temperature and pressure conditions. The structural evolution of coal macromolecules, driven by tectono-thermal processes, is the key to understanding coal rank transition and geological evolution. The structural alignment of polycyclic aromatic hydrocarbons (PAHs) in coals represents a critical indicator for characterizing coal rank transition and geological evolution. However, due to limited studies, there is a lack of systematic experimental demonstration and theoretical support for the structural alignment and microstructural characteristics of PAHs in coals, as well as their intrinsic relationships with the structural transition of coal macromolecules, during pyrolysis. Methods This study …

Sedimentary Characteristics And Coal Accumulation Patterns Of The Permian Shallow-Water Deltas In Shandong And Its Adjacent Regions, Feng Kai, Li Zengxue, Li Ying, Li Xuchao, Zhang Hui, Zhou Xiaojuan

Coal Geology & Exploration

Objective The Shanxi Formation, deposited during the critical transitional period from the sedimentary filling of epicontinental sea basins to the sedimentation of continental basins, exhibits well-developed shallow-water delta systems and significant coal-forming processes. This study aims to reveal the characteristics of sedimentary environment transformation during the late stage of sedimentary filling of epicontinental sea basins in North China. To this end, the Early Permian shallow-water delta systems in Shandong and its adjacent regions during that period was investigated, including their primary sedimentary characteristics, the predominant bases of sedimentary transformation, and the lithofacies paleogeographic characteristics of coal-forming processes.Methods Based on …

Geological Characteristics And Enrichment-Accumulation Patterns Of Coalbed Methane Within The Jurassic Strata In The Miquan Area Along The Southern Margin Of The Junggar Basin, Wu Luofei, Yang Kangjun, Zhang Jie, Shi Yongxia, Fu Haijiao, Yang Shuguang, Wang Gang, Liu Mengmeng, Li Yueguo, Wang Xiaoming

Coal Geology & Exploration

Objective The southern margin of the Junggar Basin (also referred to as the southern Junggar) possesses abundant medium- to low-rank coalbed methane (CBM) resources, with significant progress achieved in CBM exploration and production. However, there remains a lack of systematic understanding of the genetic mechanisms of CBM within the Middle-Lower Jurassic strata, along with its accumulation and evolution laws, in the Miquan area, southern Junggar. This absence restricts the commercial development of CBM in these strata.Method Focusing on CBM within the Middle-Lower Jurassic Xishanyao and Badaowan formations in the Miquan area, this study further identified the CBM origins and …

Exploring Water Migration Patterns In Reconstructed Soil Layers For Waste Dumps Of Open-Pit Coal Mines Based On Ct Scanning, Fan Tingyu, Zhang Xinghui, Lu Akang, Yang Changde, Wang Shun, Wang Xingming, Sun Xueliang, Ji Quancai

Coal Geology & Exploration

Objective In the arid regions of western China, the ecological restoration of waste dumps within open-pit coal mines plays a key role in green mine construction, while creating a suitable soil profile structure serves as a prerequisite for the ecological restoration.Methods This study investigated the reconstructed soils with a three-layer sponge-like structure consisting of the topsoil, sandy-soil, and mudstone layers for the waste dump of the Hongshaquan open-pit coal mine in Xinjiang. Using computed tomography (CT) scanning, a three-dimensional (3D) pore network model (PNM), and water migration simulation, this study systematically analyzed the pore structures and water migration characteristics …

Technologies For Controlling Water Inrushes From Coal Seam Floors Under Flowing Water And Their Water Plugging Performance, Yang Zhibin

Coal Geology & Exploration

Objective Limestone water hazards in coal seam floors represent one of the two primary categories of mine water hazards in China. Limestone aquifers are generally characterized by abundant static water reserves and considerable dynamic water recharge. To reduce economic losses and casualties caused by water inrushes from limestone aquifers, post-disaster emergency rescue through grouting for water plugging is frequently carried out under flowing water.Methods Based on numerous cases of water inrush control under flowing water in China and the fundamental requirements for control scheme design, this study presents a systematic review of existing technologies for water inrush control under …