Engineering Commons^™

Neural Networks For Improved Signal Source Enumeration And Localization With Unsteered Antenna Arrays, John T. Rogers Ii

Theses and Dissertations

Direction of Arrival estimation using unsteered antenna arrays, unlike mechanically scanned or phased arrays, requires complex algorithms which perform poorly with small aperture arrays or without a large number of observations, or snapshots. In general, these algorithms compute a sample covriance matrix to obtain the direction of arrival and some require a prior estimate of the number of signal sources. Herein, artificial neural network architectures are proposed which demonstrate improved estimation of the number of signal sources, the true signal covariance matrix, and the direction of arrival. The proposed number of source estimation network demonstrates robust performance in the case …

Flood Inundation Mapping Of The Catalpa Creek Watershed, Subodh Poudel

Theses and Dissertations

This study addresses flood risk assessment in the Catalpa Creek watershed, located in northeast Mississippi, USA. Employing the Hydrological Modeling System (HEC-HMS) and the River Analysis System (HEC-RAS), integrated models were developed and calibrated, to predict flood behavior within the watershed. The study conducted flood frequency analyses for return periods ranging from 2 to 100 years and generated flood inundation maps, pinpointing flood-prone areas. Mitigation measures for flood risk management were recommended. The results underscore the effectiveness of the integrated modeling approach for simulating and understanding the complex dynamics of flood events. The research identified critical flood-prone zones, emphasizing the …

Visual Acquisition And Detection Of Manned Fixed-Wing Aircraft And Rotorcraft: An Analysis Of Pilots' Perception And Performance, Rania Bassou

Theses and Dissertations

In recent years, the rapid advancement of Unmanned Aircraft Systems (UAS) has led to an increasingly complex National Airspace System (NAS), necessitating a comprehensive understanding of factors that impact pilot visual acquisition and detection of other aircraft (including manned fixed-wing, rotorcraft, and UAS). The objective of this study is to investigate factors that affect pilot performance in visually acquiring and detecting other manned-fixed wing aircraft and manned rotorcraft using a multi-method approach, incorporating qualitative and quantitative data analysis. A diverse sample of pilots with varying flight experience participated in the study. Participants were exposed to a series of flight test …

Stream Water Quality Under Baseflow Conditions In A Livestock Production Area, Maryi Lorena Chavarro Chaux

Theses and Dissertations

This study evaluates the spatial and temporal impacts of implemented Best Management Practices (BMP) on stream water quality under baseflow conditions in a stream segment affected by livestock production. The BMPs includes 10-m fenced riparian zone and crossing paths along the reach segment. Grab water samples and water quality monitoring were collected biweekly from July 2019 to March 2022. Water quality parameters included temperature, dissolved oxygen, electric conductance, total dissolved solids, turbidity, and pH. Water samples were lab analyzed for sediments and nutrients. Results evidenced poor water quality before BMPs implementation, with nutrient concentrations exceeding the nation's and state's criteria. …

Assessing The Relationship Between Soil Health/Quality And Water Quality In The Mississippi Delta, Laura Andrea Sarmiento Rodriguez

Theses and Dissertations

Several studies have reported agronomic benefits by improving soil health/quality, but uncertain knowledge remains when determining specific impacts on water quality off-field. This study investigated the links between runoff water quality and soil health/quality in agricultural fields of the Mississippi delta under three land management scenarios: Conservation Reserve Program (CRP), vegetative buffer (VB), and row crops (RC). Using the Soil Management Assessment Framework (SMAF), a Soil Quality Index (SQI) was obtained based on ten soil health/quality indicators from 2008 and 2012 datasets. The SMAF identified significant differences in soil health/quality improvements among scenarios over a four-year period. Varied relationships between …

Mechanical Characterization Of Functionally Graded M300 Maraging Steel Cellular Structures, Bradley Jay Sampson

Theses and Dissertations

Traditional methods for increasing the energy absorption of a structure involve using a stronger material or increasing the volume of the structure, resulting in a higher cost or additional weight. Additive manufacturing (AM) can be used to maximize the energy absorption of materials with the ability to create complex geometries such as cellular structures. Previous work has shown that the energy absorption of additively manufactured parts can be improved through functionally graded cellular structures; however, this strategy has not been applied to ultra-high strength steel materials. This work characterizes the effect of multiple functional-grading strategies (e.g. uniform, rod-graded, size-graded) on …

An Investigation Into Applications Of Canonical Polyadic Decomposition & Ensemble Learning In Forecasting Thermal Data Streams In Direct Laser Deposition Processes, Jonathan Storey

Theses and Dissertations

Additive manufacturing (AM) is a process of creating objects from 3D model data by adding layers of material. AM technologies present several advantages compared to traditional manufacturing technologies, such as producing less material waste and being capable of producing parts with greater geometric complexity. However, deficiencies in the printing process due to high process uncertainty can affect the microstructural properties of a fabricated part leading to defects. In metal AM, previous studies have linked defects in parts with melt pool temperature fluctuations, with the size of the melt pool and the scan pattern being key factors associated with part defects. …

Electroencephalography And Biomechanics Of The Basketball Throw, Phong Ky Phan

Theses and Dissertations

According to various studies, compared with novice athletes, experts exhibit superior integration of perceptual, cognitive, and motor skills. This superior ability has been associated with the focused and efficient organization of task-related neural networks. Specifically, skilled individuals demonstrate a spatially localized or relatively lower response in brain activity, characterized as ‘neural efficiency’, when performing within their domain of expertise. Previous works also suggested that elite basketball players can predict successful free throws more rapidly and accurately based on cues from body kinematics. These traits are the result of a prolonged training of specific motor skills and focused excitability of the …

Study Of Surface And Groundwater Quality And Quantity At Watershed Scale In Mississippi, Dipesh Nepal

Theses and Dissertations

Hydrology and water quality are affected by land use and climate changes. Mississippi’s diverse agro–ecosystem comprises of a range of land use land cover (LULC) including agriculture, forest, wetlands, urban, and grasslands. The objectives of this study were to investigate the impacts of various factors such as Best Management Practices (BMPs), wetlands, LULC, and climate changes on water quality and quantity. The hydrologic and water quality responses to dynamic LULC input in Soil and Water Assessment Tool (SWAT) were evaluated. Results showed that agricultural and forest expansion were major drivers of hydrologic and water quality changes in Big Sunflower River …

Network Layer Reliability And Security In Energy Harvesting Wireless Sensor Networks, Jing Yang

Theses and Dissertations

Wireless sensor networks (WSNs) have become pivotal in precision agriculture, environmental monitoring, and smart healthcare applications. However, the challenges of energy consumption and security, particularly concerning the reliance on large battery-operated nodes, pose significant hurdles for these networks. Energy-harvesting wireless sensor networks (EH-WSNs) emerged as a solution, enabling nodes to replenish energy from the environment remotely. Yet, the transition to EH-WSNs brought forth new obstacles in ensuring reliable and secure data transmission.

In our initial study, we tackled the intermittent connectivity issue prevalent in EH-WSNs due to the dynamic behavior of energy harvesting nodes. Rapid shifts between ON and OFF …

Moisture Effects On Visible Near-Infrared And Mid-Infrared Soil Spectra And Strategies To Mitigate The Impact For Predictive Modeling, Francis Hettige Chamika Anuradha Silva

Theses and Dissertations

Instrumental disparities and soil moisture are two of the key limitations in implementing spectroscopic techniques in the field. This study sought to address these challenges through two objectives. The first objective was to assess Visible-near infrared (VisNIR) and mid-infrared (MIR) spectroscopic approaches and explore the feasibility of transferring calibration models between laboratory and portable spectrometers. The second objective addressed the challenge of soil moisture and its impact on spectra. The portable spectrometers demonstrated comparable performance to their laboratory-based counterparts in both regions. Spiking with extra-weight, was the most effective calibration transfer method eliminating disparities between instruments. The samples were rewetted …

Cement Stabilization Of Poorly Graded Sand, Lana Grayson Brown Sisung

Theses and Dissertations

Stabilization of poorly graded sand in full-scale applications is challenging. This thesis evaluated cement-stabilized sand and had two objectives: (1) evaluation of stabilized material using the PM device to quantify engineering properties for future comparison to alterative materials and to investigate the effectiveness of the device with sand and (2) investigation of the merits of alternative application of cement to sand to benchmark against other topically applied materials. The PM device was successfully used to recommend 10% cement for field studies with one sand, successfully allowed data collection in laboratory and field applications, and its potential in sand seems promising …

Traffic Light Detection And V2i Communications Of An Autonomous Vehicle With The Traffic Light For An Effective Intersection Navigation Using Mavs Simulation, Mahfuzur Rahman

Theses and Dissertations

Intersection Navigation plays a significant role in autonomous vehicle operation. This paper focuses on enhancing autonomous vehicle intersection navigation through advanced computer vision and Vehicle-to-Infrastructure (V2I) communication systems. The research unfolds in two phases. In the first phase, an approach utilizing YOLOv8s is proposed for precise traffic light detection and recognition, trained on the Small-Scale Traffic Light Dataset (S2TLD). The second phase establishes seamless connectivity between autonomous vehicles and traffic lights in a simulated Mississippi State University Autonomous Vehicle Simulation (MAVS) environment resembling a small city with multiple intersections. This V2I system enables the transmission of Signal Phase and Timing …

Soft Robot Trajectory Generation: Enabling Soft Robot Arms To Reliably And Effectively Perform Real World Tasks Through Optimization, Haley P. Sanders

Theses and Dissertations

The robotic platform presented in this thesis is underdamped with high inertia and can store potential energy in its compliant joints, making it ideal for many different types of real-world tasks for which traditional rigid-robots are ill-suited. Some real-world tasks suited to soft robots include high impact tasks like hammering a nail into a wall or moving heavy objects with other robot or human teammates while using relatively little power. Some of the same characteristics which make soft robots useful, such as their underdamped, highly compliant joints, also make motion planning and control for soft robots difficult. In this thesis, …

Drop Retention And Departure In Shear Flow On Structured Superhydrophobic Surfaces, Blake Morgan Lyons

Theses and Dissertations

Water is often found adhering to surfaces in droplet form. Droplets can develop as a result of precipitation, condensation, or chemical reactions. Drops are retained or held on a surface due to a retention force exerted on the drop by the surface. This retention force is a function of the surface tension of the liquid, drop geometry, and the contact angle between the drop and the surface. When external or body forces exceed this retention force the drop begins to move. This thesis seeks to understand and quantify the forces present at the point of droplet departure once it begins …

Development Of A Submerged Hydraulic Jump Prediction Method Using Documented Fatal Incidents At Low-Head Dams, Caleb Mccurry

Theses and Dissertations

Low-head dams are known to be dangerous due to a recirculating current that, when formed, drowns recreationalists who become trapped in the current. Efforts to mitigate the hazard of low-head dams have led to the compilation of a database of low-head dams with proven fatalities. Additionally, flume-based experiments along with well-known hydraulic equations have been used to create a spreadsheet-based system for predicting the occurrence of the dangerous recirculating current, otherwise known as a submerged hydraulic jump. The premise of the spreadsheet is that if the normal depth calculated with the Mannings Equation for the downstream reach is between the …

A Series Of Improved And Novel Methods In Computer Vision Estimation, James J. Adams

Theses and Dissertations

In this thesis, findings in three areas of computer vision estimation are presented. First, an improvement to the Kanade-Lucas-Tomasi (KLT) feature tracking algorithm is presented in which gyroscope data is incorporated to compensate for camera rotation. This improved algorithm is then compared with the original algorithm and shown to be more effective at tracking features in the presence of large rotational motion. Next, a deep neural network approach to depth estimation is presented. Equations are derived relating camera and feature motion to depth. The information necessary for depth estimation is given as inputs to a deep neural network, which is …

Effectiveness Of Intelligent Transportation Systems On Utah Roadways, Matthew Cline Davis

Theses and Dissertations

This thesis presents the findings of a comprehensive research study conducted for the Utah Department of Transportation (UDOT) to evaluate the effectiveness of commonly deployed Intelligent Transportation System (ITS) treatments in Utah, with a focus on Variable Message Signs (VMS), traffic cameras, and Road Weather Information System(s) (RWIS) sites. The study aimed to determine the impact of these ITS treatments on mobility and safety for Utah's unique road conditions and configurations. Three primary analyses were performed: a diversion rates analysis to assess the effectiveness of VMS on Utah freeways during incidents; a weather analysis to evaluate the effectiveness of VMS …

Advancements In Levitated Optomechanics: Exploring Plasmon-Enhanced Light-Matter Interactions In Optical Trapping, Siavash Mirzaei Ghormish

Theses and Dissertations

Optical trapping of metallic nanoparticles investigates phenomena at the interface of plasmonics and optical micromanipulation. This thesis combines ideas from the optical properties of metals, originating in solid-state physics, with the force mechanisms resulting from optical trapping. I explore the influence of enhanced light-matter interaction due to the plasmon resonances of gold particles on their trapping properties. I present theories for trapping mechanisms of gold metallic particles and then verify these theories through experiments. Optical trapping of metallic nanoparticles is considered challenging, especially in air, as they are highly absorbing and reflecting at optical wavelengths. Yet the optical levitation of …

Investigating The Effects Of Unfused Powder Damping In Laser Powder Bed Fusion, Samuel Hao Teng

Theses and Dissertations

This study uses Additive Manufacturing (AM) processes to fabricate 316L stainless steel beams with pockets of unfused powder for increased damping. Modal testing was completed to compare damping factors of beams with varying pocket geometries as well as number of pockets and pocket location. For the first three bending modes that were tested, an initial damping increase was observed when pocket height is greater than powder diameter. Following the initial increase there is a height threshold, which is mode dependent, that is required to achieve a statistically significant increase in damping.

Economy Of Scale Of Energy Intensity In Aquifer Storage And Recovery (Asr), Alyson Haley Rapp

Theses and Dissertations

More water utilities are adopting Aquifer Storage and Recovery (ASR) to balance long-term water supply and demand. Due to large implementation and operation costs, ASR projects need to be optimized, particularly for energy use, which is a major operating expense. This study examines the relationships among energy use, recharge, and recovery at two ASR projects in the western United States. The major finding is an economy of scale for recovery processes, but not for gravity-fed recharge processes. The economy of scale found is as follows: the energy intensity recovered decreases with volume. This suggests it is more energy-efficient to recover …

Analysis And Simulation Of Nuclear Thermal Energy Storage Systems For Increasing Grid Stability, Jaron Wallace

Theses and Dissertations

With the growing capacity of renewable energy production sources, nuclear energy, once a mainstay of power generation, faces challenges due to its limited adaptability to fluctuating energy demands. This inherent rigidity makes it less desirable than the more flexible renewable sources. However, integrating thermal energy storage (TES) systems offers a promising avenue, enabling nuclear power plants (NPPs) to enhance their operational flexibility and remain competitive in an evolving renewable market. A comprehensive ranking methodology has been introduced, delineating the criteria and processes to determine the most synergistic TES/NPP design couplings. This methodology considers the unique characteristics of both current and …

Using Jtag For External Scrubbing On The Amd Versal Acap, Michael L. Bjerregaard

Theses and Dissertations

The Versal Adaptive Compute Acceleration Platform (Versal ACAP) is a system-on-chip (SoC) developed by AMD Xilinx. To help protect the programmable logic from soft errors, the configuration needs to be constantly checked and repaired through a process called scrubbing. This thesis provides a methodology for scrubbing the configuration over JTAG. The scrubber uses two platform device image (PDI) files, one to read the configuration and one to send corrected frames. The methodology is characterized to determine the time it takes to completely scrub the configuration. The designed scrubber was able to scrub the VM1802 in 11.5 seconds, or 41.6 Mbits/second, …

An Inexpensive, 3d Printable, Arduino And Bluray-Based, Confocal Laser And Fluorescent Scanning Thermal Microscope, Justin Loose

Theses and Dissertations

The Fluorescence Scanning Thermal Microscope (FSTM v3.0), was designed to create an inexpensive, and easily manufactured, device for measuring the diffusivity of samples with microscopic locational precision. This was accomplished by using a Blu-ray device known as a PHR-803T, referred to in this work as a PHR. The optics in the PHR are nearly identical in function to conventional devices used in thermoreflectance microscopy, making the PHR extremely useful to integrate into the FSTM design. The focus of this thesis is the application of the FSTM as a confocal microscope using 3D printed components and various low-cost devices to operate …

Modeling The Influence Of Vibration On Flow Through Embedded Microchannels, Joseph S. Seamons

Theses and Dissertations

The influence of vocal fold (VF) vibration on perfused flow through VF vasculature is an area of research that has previously received limited attention. The aim of the research presented in this thesis was to contribute towards an improved understanding of the effects vibration on perfusion through vasculature within the VFs. This was done using a series of computational simulations of geometric changes to, and perfusion through, microchannels embedded in VF models. A computational structural model based on synthetic VF models used in previous experimental studies was first developed. The model and its embedded microchannel were initially studied under static …

Federated Active Learning For Network Intrusion Detection, Matthew D. R. Sauer

Theses and Dissertations

This thesis addresses challenges with detecting attacks on computer networks within a Federated Learning (FL) framework, when labeled instances are few. We explore the integration of active learning (AL) and semi-supervised learning (SSL). AL efficiently uses data that would otherwise be wasted or require substantial time for labeling. SSL provides capacity to train models that have a limited amount of labeled data, by utilizing additional unlabeled data that is available. We show how FL combined with AL or SSL can realize a detection system that adapts and trains quickly to new networks, reducing the total amount of data labeling needed. …

Marss: Multi-Agent Reinforcement Learning For Satellite Swarms, Nicholas J. Yielding

Theses and Dissertations

Multi-agent systems and swarms in spacecraft formation flying are of ever-increasing importance in a contested space environment—use of multiple spacecraft to contribute to a cooperative mission potentially increases positive outcomes on orbit, while autonomy becomes an ever more important requirement to reduce reaction time in dynamic situations and lower the burden on space operators. This research explores difficult swarm Guidance Navigation and Control (GNC) scenarios using Deep Reinforcement Learning (DRL). DRL polices are trained to provide guidance inputs to agents in multi-agent swarm environments for completing complex, teamwork focused objectives in geosynchronous orbit. An example scenario is explored for a …

An Improved Saliency Map With Trustworthiness For Localizing Abnormalities In Medical Imaging, Nolan C. Skelly

Theses and Dissertations

Saliency maps are a widely used methodology to make deep learning models more interpretable. They provide post-hoc explanations through identification of the most pertinent areas of an input medical image. These techniques have been assessed based on 1) localization utility, 2) sensitivity to model weight randomization, 3) repeatability, and 4) reproducibility. Ten saliency map techniques will be tested, Grad, Smooth Grad, Integrated Gradients, Smooth Integrated Gradients, XRAI, Grad-CAM, Guided Backpropagation, Guided GradCAM, GradCAM++, and ScoreCAM. The neural networks used to predict and read medical information require a reliable solution to provide medical practitioners intelligible results. Using the information of two, …

Process-Structure-Property Relationships Of Nanofibers For Biomedical Applications, Dipasree Bhowmick

Theses and Dissertations

This thesis explores the fabrication, characterization, and applications of nanofiber membranes utilizing Forcespinning® technology. Two distinct nanofiber systems were developed and evaluated, one focusing on pH-responsive Eudragit-baicalin loaded nanofibrous membranes for wound healing and the second one on thermo-responsive nanofiber-hydrogel (PNIPAAm) systems for biosensing applications, specifically dopamine detection. In the first project, nanofiber membranes loaded with Eudragit and baicalin demonstrated superior antibacterial properties against both gram-negative (E. coli) and gram-positive (B. meg) bacteria. Additionally, these membranes exhibited antioxidant properties and enhanced cell proliferation of 3TT cells, making them promising candidates for wound healing dressings. In the second project, a …

Analyzing The Effects Of Ultrafast Laser Processing On Mechanical Properties Of 3d-Printed Pla Parts, Darshan Pramodbhai Yadav

Theses and Dissertations

Recent advances in additive manufacturing technologies have already led to wide-scale adoption of 3D-printed parts in various industries. The expansion in choice of materials that can be processed, particularly using Fused Deposition Modeling (FDM), and the steady advancements in dimensional accuracy control have extended the range of applications far beyond rapid prototyping. However, additive manufacturing still has considerable limitations compared to traditional and subtractive manufacturing processes. This work addresses limitations associated with the as-deposited surface roughness of 3D-printed parts. The effects of roughness-induced stress concentrations were studied on ultimate tensile strength and fatigue life. The samples were manufactured using a …