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Learning And Control For Complex Multiagent Systems, Vrushabh S. Donge

Electrical Engineering Dissertations - Archive

Complex multiagent systems (MASs) are pervasive in various fields, from power system networks, and autonomous robotics to traffic management, where groups of agents interact to achieve collective objectives. Effective coordination and control of such systems pose significant challenges due to their inherent complexity and the need for adaptive, efficient strategies. This dissertation explores combining data-driven approaches, reinforcement learning (RL), and control theory to address these challenges. We present novel methodologies for learning and controlling complex MASs, emphasizing the development of adaptive algorithms that can autonomously adapt to dynamic environments, collaborate with other agents, and optimize system-wide performance. Our findings offer …

Enhancing Biomedical Imaging With Ai: Compression, Prediction, And Multi-Modal Integration For Clinical Advancement, Mohammad Sadegh Nasr

Computer Science and Engineering Dissertations - Archive

This dissertation delves into the enhancement of biomedical image analysis through the deployment of artificial intelligence methodologies, focusing on the transition from theoretical innovation to practical clinical utility. Spanning four cornerstone projects, the work encapsulates the development of predictive models for spatial transcriptomics, efficient image compression for cancer pathology slides, and critical evaluations of histopathology slide search engines. The first project employs Random Forest Regression and spatial point processes to forecast cell distribution patterns, thereby offering a novel perspective on gene expression in embryogenesis at a single-molecule resolution. The second venture introduces a Variational Autoencoder (VAE) that sets a new …

Process-Driven Microstructure Tailoring During Additive Manufacturing Of Ti-6al-4v, Ahmet Alptug Tanrikulu

Material Science and Engineering Dissertations - Archive

In recent years, additive manufacturing (AM) has attracted the attention of many researchers due to the technology providing opportunities in terms of improved functionality, production repeatability, efficiency, and cost and time issues. While AM techniques made possible the realization of complex geometries, their use in critical applications have faced challenges due to the anisotropic characteristic of AM-built parts. More specifically, non-equilibrium AM processes involve steep temperature gradients and rapid solidification, yielding a unique microstructure, e.g., columnar-shaped grains with preferred texture, in final AM-built products and hence anisotropic mechanical properties. Despite significant studies on improving the microstructure of AM-built parts, it …

Spatially Resolved Elastic Modulus Of Magnesium Silicate Hydrate: A Cementitious Material, Arif Syed

Material Science and Engineering Theses - Archive

Magnesium-based cements such as magnesium silicate hydrate (MSH) have drawn interest as an environmentally friendly substitute for ordinary Portland cement because of their potential for reduced carbon footprint. The precise determination of these materials' elastic moduli is important to better assess their mechanical performance. Atomic force microscopy (AFM) is an effective tool for precise and spatially resolved quantification of nanomechanical characteristics of materials, including thin films. In this study, elastic modulus maps of MSH grown on single crystal mica surfaces were obtained using amplitude modulation-frequency modulation AFM. The effects of the Mg:Si ratio and morphology on the elastic modulus of …

Design And Demonstration Of An Inertial-Stabilized Single-Axis Headlamp For Mobile Systems, Thomas Avery Allsup

Mechanical and Aerospace Engineering Dissertations - Archive

The introduction of adaptive headlamps has added left and right movement of the headlamps to enhance the vision of the driver during a turn at night. Adaptive headlamps also allow up and down motion of headlamps in either two discrete positions with low and high beams based on vehicle speed and oncoming traffic lights or using the vehicle suspension measurement to adjust headlamp beam angles in any angle between low and high. Using the vehicle suspension ignores the roadway influence on where the headlamps should be positioned to illuminate the roadway for the driver. This dissertation develops governing equations and …

On The Development Of A Sensing System Methodology To Evaluate The Viscoelastic Properties Of Soft Tissues As A Means Of Disease Prognosis, Shashank S. Kumat

Mechanical and Aerospace Engineering Dissertations - Archive

Identification of tissue viscoelastic properties could provide valuable information for assessing its healthiness or disease state. Current technologies present challenges to access and perform localized tissue assessment in confined spaces in the human body through contact indentation/palpation. As such, there is a need for a diagnostic system capable of measuring tissue relaxation response at the local site by accessing the tissue through a natural orifice. This dissertation presents a strain gauge-based uniaxial micro-force sensor, part of the aforementioned system, capable of measuring tissue response data in confined human space environments. A sensing system design methodology is developed and presented. The …

Optimizing Energy Efficiency And Performance In High-Performance Computing Through Advanced Direct-To-Chip Liquid Cooling And Labview-Based Monitoring And Analysis, Chandraprakash Ashok Hinge

Mechanical and Aerospace Engineering Dissertations - Archive

This research endeavors to significantly enhance energy efficiency and performance in the realm of high-performance computing (HPC). This goal is pursued through a synergistic approach that leverages advanced direct-to-chip liquid cooling systems and integrates LabVIEW for real-time monitoring and analysis within data centers. The primary aims of this study are manifold. First, it seeks to evaluate the effectiveness of different single-phase liquid coolants when employed in direct-to-chip cold plate cooling for HPC systems. Additionally, the research focuses on characterizing row manifolds, crucial elements in the design of efficient data centers. The study also endeavors to devise a strategic control mechanism …

Multiple Dipole Source Position And Orientation Estimation Using Non-Invasive Eeg-Like Signals, Saina Namazifard

Mechanical and Aerospace Engineering Dissertations - Archive

The human brain comprises of neurons that connect with each other via electrical signals. One can record and measure these activities using an electroencephalogram (EEG). An essential use of the EEG is in locating the generating source of these signals, usually approximated by dipoles. This is important because, in some particular circumstances, neurons may not function optimally and could make the equivalent dipole generate abnormal signals. This could be a result of seizures or other brain disorders. In order to isolate such disorders, the challenge is to find a non-invasive way to locate the anomalous source. This research aims to …

Thermo-Mechanical Analysis Of Heterogenous Integrated Packages And Immersion Cooling Of Data Center Servers, Krishna Bhavana Sivaraju

Mechanical and Aerospace Engineering Dissertations - Archive

III-V materials such as Gallium Arsenide (GaAs) and Indium Phosphide (InP) are used as substrates for opto-electronic devices like vertical cavity surface emitting lasers (VCSEL), edge emitting lasers and light emitting diodes. System in Package integration of the III-V materials to silicon requires a reliable bonding technique. Though there are several bonding techniques like direct wafer bonding like hetero-epitaxially grown islands on a silicon wafer bonding enable the bonding, flip-chip bonding is used in this study owing to its superior electrical connectivity, mechanical reliability, heat conduction capability and ease of fabrication due to self-alignment. Finite element models of four different …

Noninvasive Mapping Of Global And Regional Functional Connectivity In The Brain Of Children With Drug Resistant Epilepsy And Healthy Controls, Ludovica Corona

Bioengineering Dissertations - Archive

For patients with drug resistant epilepsy (DRE), resective surgery is the most effective treatment to achieve seizure-freedom. Its success largely depends on the resection, ablation, or disconnection of the epileptogenic zone (EZ), defined as the minimal area indispensable for the generation of seizures, with minimal or no functional deficits. To date, there is no clinical exam to delineate the EZ unambiguously. Instead, the EZ is indirectly defined through multiple noninvasive diagnostic tests used by the multidisciplinary epilepsy team, whose results are often insufficiently concordant or inconclusive. Thus, extra-operative intracranial electroencephalography (iEEG) monitoring may be needed to precisely define the EZ …

Lung Cancer Growth Forecasting And Classification Models By Machine Learning Using A Novel 2d Co-Culture High Throughput Device, Adam Adrien Germain

Bioengineering Dissertations - Archive

Co-culture devices have commonly been used during in vitro experimentation to create therapeutic testing devices for lung cancer that more closely mimic the in vivo environment to gain better insights into new therapies and the reasons for inconsistency for current therapies. Moreover, AI (artificial intelligence) in the form of convolutional neural networks (CNN) and convolutional long-short term memory neural networks (convLSTM) are being used to classify, diagnose, and predict drug outcomes from the visual data provided by clinical imaging modalities, such as CT-scans, MRIs, or histopathological slides among others, or from numerical and textual data gathered from the genetic testing …

Advances And Applications In Ultrasound-Switchable Fluorescence Imaging, Liqin Ren

Bioengineering Dissertations - Archive

Cancer diagnosis is a prerequisite for further medical therapy and treatment. Near-infrared (NIR) fluorescence imaging is a desirable modality without invasiveness and nonionizing radiation. However, fluorescence suffers from a strong light scattering in tissues, leading to a low spatial resolution and low sensitivity in centimeter-deep tissue (limited to several millimeters). To enhance spatial resolution and avoid the high scattering of conventional fluorescence imaging in deep tissue, ultrasound-switchable fluorescence (USF) imaging has emerged as a highly promising technique for biomedical imaging and research. The principle of improving spatial resolution in USF imaging is to confine the fluorescence emission from thermosensitive fluorophores …

Development Of Multiscale And Multidimensional Light Sheet Microscopy For Image-Based Modelling Of Organogenesis, Tanveer Ashwini Ashwini Teranikar

Bioengineering Dissertations - Archive

Behavioral analysis of individual cells, in the form of structural phenotypes arising in response to mechanical stimuli or genomic alterations as small molecule intermediates of disease, are instrumental for understanding organogenesis. In this regard, dynamic cell tracking or temporal changes in cell shape, area and size are vital for modelling tissue interactions. However, optical diffraction limits imposed by lenses, hinders high resolution volume reconstruction of microscale biological processes and subcellular organelles. Thereby, isotropic intensity is restricted to limited focal volumes, reducing imaging distance to less than 1 mm for high magnification. To combat this, Light Sheet Microscopes (LSM) have emerged …

Quantification Of Dynamic Changes Of Hemodynamic And Metabolic Responses To Brachial Artery Occlusion: A Broadband Near-Infrared Spectroscopy Study, Caroline Elizabeth Carter

Bioengineering Theses - Archive

Cardiovascular disease (CVD) is a leading cause of death in the United States, and non-Hispanic African Americans are at higher risk than other racial and ethnic groups. Endothelial dysfunction is a major contributor to CVD development and progression. Remote ischemic pre/conditioning (RIC), which involves exposing cells or tissues to brief sublethal stress, has been shown to protect cardiovascular cells from ischemia and reperfusion injury, including CVD. This study aimed to investigate hemodynamic and metabolic dynamics in response to 5-min forearm arterial occlusion using broadband near-infrared spectroscopy. My thesis is a tripartite investigation that weaves RIC, mitochondrial dynamics, and health disparities …

Formation And Morphological Changes Of Stress Actin Filaments In Adipose-Derived Stem Cells, Adam Priester

Bioengineering Theses - Archive

Adipose-Derived Stem Cells (ADSCs) are a sub-type of stem cell that can be collected and isolated from the adipose tissue. Adipogenesis describes the commitment and differentiation of stem cells, including ADSCs, toward the adipocyte lineage. While much research has been completed on this process in the long term (>2 weeks), morphological changes of adipogenesis during the early phase (<24 hours) are lacking in the literature and remain to be elucidated. The current study focuses on these changes in the early and later stages of adipogenesis using adipogenic differentiation factors and fluorescent imaging analyses. Quantifiable data on morphological changes during both phases can provide insight into how these changes affect later differentiation and lay the groundwork for additional research in this area. Using fluorescent image analysis, it was shown that the eccentricity of ADSCs, a measure of cellular circularity, decreases exponentially in the early phase of adipogenesis. In contrast, the cellular area appears to increase exponentially during the same early period. During the later stages of differentiation, it was shown that actin filament length decreases exponentially and the ratio of lipid to actin length increases exponentially, demonstrating that lipid accumulation outpaces actin filament shortening and increasing circularity during the later stages. These findings may be used in future studies to further define the role of actin filament-mediated morphological changes and mechanobiology during adipogenesis.

Characterizing Technology Impacts On Driving Behaviors, Crash Risks, And Infrastructure Performances, Jobaidul Boni

Civil Engineering Dissertations - Archive

In recent years, an increase in driver distraction appears due to the rise in smartphone usage and the introduction of social media. Researchers put significant efforts in examining the impacts of distracted driving, mostly focused on distraction like texting or phone call. However, scant research exists to identify the underlying factors causing the distracted driving particularly caused by social media or showing their safety implications at complex geometries such as intersections and highways. This dissertation offers three independent studies reviewing the impact of technology on drivers' actions using field tests and simulation experiments. The first field tests conducted at three …

Evaluation Of Vertical And Lateral Load Capacity Of Recycled Plastic Pin, Sehneela Sara Aurpa

Civil Engineering Dissertations - Archive

RPPs have been in use as a sustainable and effective technique to stabilize and reinforce weak ground for geotechnical purposes. Application of RPP in stabilization of slopes and improvement of load carrying capacity of foundation soil has yielded tremendous results. However, to facilitate the seamless integration of RPPs in design of foundation requires the load carrying capacity of RPP to be known. As RPP has been in use for both its vertical and lateral load carrying capacity, exploration of the load capacity of this material is essential. The objective of the study is to determine the load carrying capacity of …

Transportation Network Criticality Estimation For Hurricane Preparedness And Response Using Vulnerability Assessments, Mehrdad Arabi

Civil Engineering Dissertations - Archive

The resilience of urban transportation networks is crucial for effective evacuation, and search and rescue operations as hurricane events become more severe and frequent. This dissertation presents a comprehensive approach to identifying and evaluating critical transportation links which are crucial for emergency preparedness and response. Integrating socio-economic and environmental vulnerabilities with traditional traffic management approaches, the research underscores the importance of equitable evacuation strategies that cater to the most vulnerable populations. Employing advanced spatial analysis and data analytics with real-time GPS data, the three individual papers in this dissertation offer a dynamic assessment of evacuation behaviors, capturing the complexities of …

Utilization Of Biomimetic Molecules To Control The Carbonation Of Cementitious Phases, Muhammad Intesarul Haque

Civil Engineering Dissertations - Archive

This study introduces an innovative approach to mitigate carbonation-induced degradation of C-S-H and to enhance the carbonation properties of low calcium based cementitious materials by utilizing specific biomimetic molecules. In this study, four different biomimetic molecules were utilized. Details about their chemical formula and chemical structure can be found in Chapter 1. The dissertation is broadly focused on two aspects, Part 1 (Chapter 2 and 3) evaluated the role of biomimetic molecules in reducing the carbonation degradation of C-S-H. Part 2 (Chapter 4 and 5) assessed the effectiveness of the biomimetic molecules as performance enhancing admixture of carbonation cured dicalcium …

Experimental And Numerical Analyses Of Coupled Thermo-Hydro-Mechanical Behavior In Unsaturated Soil Under One-Dimensional Heat Transfer, Nice Kaneza

Civil Engineering Dissertations - Archive

Comprehension of the behavior of unsaturated soil in response to thermal gradients, moisture gradients, and deformation is important in geotechnics. Thermal gradients control fluid density and viscosity and moisture gradients alter thermal properties of unsaturated soil. Similarly, thermal gradients affect the thermal strain of unsaturated soil and changes in porosity influence hydraulic properties of the soil. Thus, thermal, hydraulic, and mechanical properties of unsaturated soil interact with and influence each other; the combination of these interactions form a mechanism called coupled thermo-hydro-mechanical (THM) processes. Although the study of the behavior of coupled THM processes is essential in predicting the performance …

“Increasing Renewable Energy Potential Of Landfill Gas By Electrocatalytic Conversion Of Carbon Dioxide To Methane At Low Temperature.”, Asma Akter Rony

Civil Engineering Dissertations - Archive

The conversion of carbon dioxide into methane at a low temperature has great potential to reduce current international environmental issues like global warming and will create new sources of renewable energy. The overall goal of this research is to increase renewable energy production from landfill gas using an unconventional process – electrocatalytic methanation of carbon dioxide – which has not been implemented for landfill gas yet. The electrocatalytic methanation follows the Waseda process, which applies an electric field in the presence of a Ruthenium-supported cerium oxide (CeO2) catalyst. The specific objectives of this research were: 1. To explore the impact …

Tri-Dimensional Segment-Based Urban Traffic Crash Models, Farzin Maniei

Civil Engineering Dissertations - Archive

The continuous expansion of highway and freeway networks further exacerbates the risk of traffic crashes and highlights the critical importance of freeway safety management. To improve overall road safety, many organizations acknowledge the necessity of pinpointing locations experiencing higher-than-expected crashes (known as hotspot identification, HSID), identifying the factors contributing to traffic crashes, and determining the most effective preventive measures. Previous studies highlighted two major drawbacks associated with this approach: (1) HSID based on the total number of crashes can lead to incorrectly identifying hazardous areas; (2) the arbitrary selection of a fragment size (due to the lack of explicit recommendations) …

Compound Flood Modeling Of Tropical Cyclone Events In Coastal Bays And Estuaries, Nahal Maymandi

Civil Engineering Dissertations - Archive

Flooding due to tropical cyclones can cause severe impacts on coastal communities, particularly when multiple types of flooding (e.g., coastal and riverine) interact to create a compound flood event. In typical flood hazard assessments, these drivers of flooding are considered separately, even though they may interact and produce more severe flooding. Understanding the interactions between flood drivers is necessary to accurately plan for and respond to future flood events. This dissertation aims to improve the assessment of coupled coastal, fluvial, and pluvial flooding in coastal bays and estuaries impacted by tropical cyclones. To do this, a hydrodynamic model is developed …

Tests Of A Gamma Spectrometer-Neutron Counter Relationship As A Neutron Alarm Metric In Mobile Radiation Search Systems, Jackson N. Wagner, Craig Marianno

International Journal of Nuclear Security

A mobile radiological search system (MRSS) is frequently used in nuclear security to interdict illicit nuclear material. One difficulty an MRSS faces is in characterizing its detectors’ background responses, particularly in its neutron counter(s). This difficulty adds complications to identifying the presence of neutron-emitting radiological materials during an operation. Fortunately, previous work has identified a power law relationship between muons registered by the MRSS’s gamma detectors and background neutrons. This relationship can be applied to estimate the MRSS’s background neutron count rate using that muon count rate. To test the usability of such an estimate, an MRSS was used to …

Determinants Of Poor Perinatal Outcomes Among Babies Born Of Mothers With Preeclampsia At Mama Lucky Kibaki Hospital, Nairobi County, Sarah Wambui Chege

MSc in Advanced Practice Midwifery

Background: Preeclampsia is a life-threatening pregnancy illness characterised by the onset of hypertension in a non-hypertensive woman after 20 weeks of pregnancy. Studies have connected preeclampsia to significant adverse effects on the mother and the newborn, a common obstetric emergency in Kenya. Determinants of poor perinatal outcomes in babies born to preeclamptic mothers have not been intensively investigated.

Objective: The study evaluated the determinants of perinatal outcomes among neonates born to mothers diagnosed with preeclampsia at Mama Lucy Kibaki Hospital between July 2021 and June 2022.

Methodology: A quantitative retrospective cross-sectional inquiry was conducted. Data reviewed comprised …

The Concept Of Land Bridge Marshes In The Mississippi River Delta And Implications For Coastal Restoration, John W. Day, Robert R. Twilley, Angelina Freeman, Brady Couvillion, Tracy Quirk, Navid Jafari, Giulio Mariotti, Rachael Hunter, Charles Norman, G. Paul Kemp, John R. White, Ehab Meselhe

Faculty Publications

Louisiana has high coastal wetland loss rates due to natural processes such as subsidence and anthropogenic activities such as construction of river levees and dams, pervasive alteration of surface hydrology by local industries such as oil and gas, and navigation. With the exception of the Atchafalaya River discharge area, most of Louisiana's marsh coastline is retreating and coastal marshes are degrading. In the inactive degrading delta regions, there exists a previously uncharacterized landform referred to colloquially as coastal ‘land bridge’ marshes. Land bridge marshes are saline or brackish marshes fronting large estuarine bays or lakes with sufficient fetch and wave …

Atmospheric Flash Drought In The Caribbean, Craig A. Ramseyer, Paul W. Miller

Faculty Publications

Despite the intensifying interest in flash drought both within the United States and globally, moist tropical landscapes have largely escaped the attention of the flash drought community. Because these ecozones are acclimatized to receiving regular, near-daily precipitation, they are especially vulnerable to rapid-drying events. This is particularly true within the Caribbean Sea basin where numerous small islands lack the surface and groundwater resources to cope with swiftly developing drought conditions. This study fills the tropical flash drought gap by examining the pervasiveness of flash drought across the pan-Caribbean region using a recently proposed criterion based on the evaporative demand drought …

Soil Legacy Nutrients Contribute To The Decreasing Stoichiometric Ratio Of N And P Loading From The Mississippi River Basin, Zihao Bian, Hanqin Tian, Shufen Pan, Hao Shi, Chaoqun Lu, Christopher Anderson, Wei Jun Cai, Charles S. Hopkinson, Dubravko Justic, Latif Kalin, Steven Lohrenz, Steven Mcnulty, Naiqing Pan, Ge Sun, Zhuonan Wang, Yuanzhi Yao, Yongfa You

Faculty Publications

Human-induced nitrogen–phosphorus (N, P) imbalance in terrestrial ecosystems can lead to disproportionate N and P loading to aquatic ecosystems, subsequently shifting the elemental ratio in estuaries and coastal oceans and impacting both the structure and functioning of aquatic ecosystems. The N:P ratio of nutrient loading to the Gulf of Mexico from the Mississippi River Basin increased before the late 1980s driven by the enhanced usage of N fertilizer over P fertilizer, whereafter the N:P loading ratio started to decrease although the N:P ratio of fertilizer application did not exhibit a similar trend. Here, we hypothesize that different release rates of …

Perturbation Based Decomposition For Motor Unit Number Estimation, Anna T. Pham

Master's Theses

Motor unit number estimation (MUNE) is of clinical significance because information associated with motor unit populations and the loss of motor units over time are crucial to the diagnosis and monitoring of neuromuscular disorders. The responses of individual motor units can be extracted through incremental stimulation of a muscle group of interest and further analyzed through various methods to compute the MUNE. In this work, the utility of the perturbation-based decomposition by Szlavik will be investigated for this application and compared to the original MUNE approach developed by McComas. Successful decomposition may suggest an alternative method for motor unit number …

Research Practice Partnership: Teacher Turnover Patterns In The State Of Nebraska, Brian W. Stevens

Educational Leadership Theses, Dissertations, and Student Creative Activity

The purpose of this research is to showcase the process of a local Research- Practice Partnership (RPP) with possible policy implications by analyzing teacher attrition patterns over many years. The RPP is a collaboration between a principal, the practitioner, and statistic students, the researchers. All groups were graduate-level students at the University of Nebraska-Omaha. This collaboration is part of the Nebraska Education Policy Research Lab (NEPRL). NEPRL is a collaboration between the Nebraska Department of Education (NDE) and researchers at the University of Nebraska. It was established as a learning lab to conduct rigorous research for the purpose of developing …