Engineering Commons^™

Design And Development Of Clinical Decision Support System For Breast Cancer Diagnosis Using Artificial Intelligence, Karthiga R

Theses and Dissertations

The prevalence of breast cancer in women worldwide is far higher than that of cancers of the lungs, brain, or liver. Increasing ageing populations and poor lifestyle habits among the general public, primarily in industrialized nations, are significant factors contributing to the rise in cancer-related mortality rates worldwide. Approximately one woman in every three will develop breast cancer. This research proposes several advanced computer methods for analyzing breast cancer images. This work analyses breast cancer in four imaging modalities: mammography, thermography, ultrasonography and histopathology.

Each modality has some limitations in diagnosing tumors in the breast region. Heavy dose in mammogram …

Better Models For High-Stakes Tasks, Jacob Ryan Epifano

Theses and Dissertations

The intersection of machine learning and healthcare has the potential to transform medical diagnosis, treatment, and research. Machine learning models can analyze vast amounts of medical data and identify patterns that may be too complex for human analysis. However, one of the major challenges in this field is building trust between users and the model. Due to things like high false alarm rate and the black box nature of machine learning models, patients and medical professionals need to understand how the model arrives at its recommendations. In this work, we present several methods that aim to improve machine learning models …

Investigations On Potassium Penta Borate Based Semi-Organic Materials For Nonlinear Optical Applications, Kamatchi K

Theses and Dissertations

Crystal growth has attained the pinnacle of a point in the current research owing to the requirement of the single crystals in the frontier field of nonlinear optics. Organic crystals exhibit high transparency, high laser damage threshold and de-localized π electron cloud. But they possess weak mechanical stability. In contrast, the inorganic crystals exhibit magnanimous mechanical and thermal properties but have modest nonlinear optical property. If we combine these two materials, then we can obtain the semi-organic materials.

Among the organic materials, the amino acids are chosen and they are mixed with inorganic material potassium penta borate octa hydrate. They …

Atmospheric Propagation Of Qubits: Laboratory Experiments To Field Demonstrations, Keith A. Wyman

Theses and Dissertations

Free-space quantum networks can enable global-scale quantum communication via satellite-based nodes and quantum ground transceivers. To enable building of robust global quantum networks, it is critical to learn how the state of the qubit is transformed while propagating through the atmosphere. With such an overarching goal, we built a laboratory based atmospheric turbulence simulator (ATS) to characterize the effects of atmospheric turbulence on an entangled pair of photons as a function of statistical quantities such as the Fried parameter or scintillation index for long-distance communication. Specifically, the changes in the statistical properties associated with a quantum source was investigated using …

Brdf Measurements And Physical Optics Modeling Applied To Anisotropic Satellite Solar Cells, Madilynn E. Compean

Theses and Dissertations

Light curve analysis is often used to discern information about satellites in geosynchronous orbits, and since solar panels comprise relatively large surface areas, their reflected energy can contribute greatly to observed light curves. Data was collected using a space qualified solar cell interrogated by a green HeNe laser. The data validated certain aspects from previous work, but also identified multi-slit behavior, showed that the specular term was a second diffraction pattern, and diagnosed the out-of-plane diffraction curvature as the conical diffraction phenomenon. Two physical-optics-based models were developed to incorporate these new features and better predict solar cell BRDF solely from …

Quantifying Atmospheric Turbulence Effects On Image Quality Using A Deconvolution Algorithm, Ahmad M. Almalki

Theses and Dissertations

Imaging through turbulence is affected by several factors including imaging system specifications, imaging system setup and more importantly the atmospheric turbulence as it is uncontrollable. One important parameter which is used to quantify the atmospheric turbulence severity is the atmospheric coherence diameter (��₀ ), known as Fried's parameter. This thesis explores ways to characterize the atmospheric turbulence effects on image quality using simulated and laboratory generated turbulence where ��₀ is estimated using a maximum a posteriori (MAP) estimator and frequency domain analysis algorithms. Furthermore, image quality metrics such as Peak Signal to Noise Ratio (PSNR), Structural Similarity (SSIM) …

Evaluating The Chief Of Staff Of The Air Force 2016 Initiative To Revitalize The Squadron: A Thematic Content Analysis Of Appreciative Inquiry Mechanisms, John M. Huntz

Theses and Dissertations

A thorough thematic analysis and literature review were undertaken to understand better the integration of AI mechanisms within the Revitalize the Squadron initiative. To facilitate the initiative's implementation, the aim is to provide commanders with practical instances, dimensions, findings, and results. Throughout the coding process, instances of AI’s mechanisms were discovered in the literature. The link between PE and HQR boosted the overall vitality within the squadron, where vitality was determined to be the goal. AI, as a whole, was not found in the literature, but the analysis determined that the Revitalize the Squadron initiative was “Appreciative” in nature.

Advances In Quaternion-Valued Neural Networks, Jeremiah P. Bill

Theses and Dissertations

This dissertation investigates the construction, optimization, and application of quaternion neural networks (QNNs) to Department of Defense (DoD) related problem sets. QNNs are a type of neural network wherein the weights, biases, and input values are all represented as quaternion numbers. This work provides a critical evaluation of the myriad different quaternion backpropagation derivations that exist in the literature, testing the performance of each on a range of regression problem sets. The optimization dynamics of QNNs are explored, presenting visualizations of QNN loss surfaces and a novel method for assessing the “smoothness” of these loss surfaces. Finally, this dissertation presents …

Test Problem Generation And Metaheuristic Selection For The Multidemand Multidimensional Knapsack Problem, Matthew E. Scherer

Theses and Dissertations

This work focuses on instance generation methods for the multi-demand multidimensional knapsack problem (MDMKP). Specifically, instance space analysis (ISA) is used to characterize the landscape of existing instances and validate the novelty of new instances generated with a novel problem generation method, the primal problem instance generator (PPIG). The instance generator is capable of producing feasible, diverse, and challenging instances by directly controlling the problem features. PPIG contributes to the previous collections of instances and is validated through instance space analysis. The research presents an in-depth empirical evaluation of existing solution procedures for the MDMKP. The portfolio of metaheuristics examined …

Improving Deep Reinforcement Learning Methodology For Autonomous Defense And Escort Of Military High-Value Assets, Joseph Liles Iv

Theses and Dissertations

This dissertation explores the application of machine learning to the control of autonomous unmanned combat aerial vehicles (AUCAVs). In particular, this research applies deep reinforcement learning methodologies to a defensive air combat scenario wherein a fleet of AUCAVs protects a military high-value asset (HVA). A collection of air battle management scenarios along with an original simulation environment and a set of designed computational experiments support the approximation of high-quality decision policies by employing Markov decision processes, approximate dynamic programming algorithms, and deep neural networks for value function approximation.

Network Vulnerability Identification For The Material Routing Problem, Carson G. Long

Theses and Dissertations

This dissertation considers the importance of identifying spatiotemporal vulnerabilities in ground distribution networks and uses operations research methods to formulate models that allow military logistic planners to implement prevention and mitigation measures regarding the routing of personnel, equipment, and supplies in contested Areas of Responsibility (AOR). For optimization models relating to identifying spatiotemporal network vulnerabilities in distribution networks, this work leverages game theory, mixed-integer programming, multi-objective optimization, and metaheuristics to inform mitigation measures for shipment routing. This research has three related components: the first component develops a multi-objective mathematical program to identify spatiotemporal vulnerabilities via myopic heuristic identification, in combination …

Analysis Of Multi-Agent Routing Solution Methodologies Exploring A Mosaic Warfare Strategy, Stephen D. Donnel

Theses and Dissertations

Recognizing that communication between assets may be possible locally but not globally (e.g., due to disruptions to a communication network), Mosaic Warfare requires the movement and operation of multiple, dispersed assets in smaller groups (i.e., tiles), within which exist hierarchical, functional relationships between assets. This research first evaluates a heuristic for an enterprise of aerial assets comprised of airborne sensors, command and control, and strike aircraft seeking to move towards and destroy stationary targets. Next, we examine routing multiple assets of different types over a network to service demands in a collaborative manner, in that, when servicing a demand, …

Pattern-Of-Life Modeling With Automatic Dependent Surveillance-Broadcast (Ads-B), Sarah J. Bolton

Theses and Dissertations

This dissertation and research were sponsored by the Air Force Research Laboratory Layered Sensing Exploitation Branch (AFRL/RYA) to investigate the utility of using the data found within aircraft secondary radar to make predictions about aircraft characteristics and intent. The research focuses on making predictions on aircraft characteristics using only the kinetic data within one type of secondary radar, Automatic Dependent Surveillance-Broadcast (ADS-B), as a surrogate for primary radar. The results from this research provide a means to reduce the reliance on a type of aircraft tracking that is vulnerable to cyber attack and other integrity concerns.

Analysis Of Coronal Magnetic Field Parameters During X- And M-Class Solar Flares, Seth H. Garland

Theses and Dissertations

Using Non-Linear Force Free Field (NLFFF) extrapolation, 3D magnetic fields were modeled from the 12-minute cadence Helioseismic and Magnetic Imager (HMI) photospheric vector magnetograms, spanning a time period of one hour before through one hour after the start of 18 X-class flares and 12 M-class flares. Several magnetic field parameters were calculated from the modeled fields directly – as well as from the power spectrum of surface maps generated by summing the fields along the vertical axis – for two different regions: areas with photospheric Bz ≥ 300 G (Active Region – AR) and areas above the photosphere with the …

An Analytical Framework For Photonic Storage And Retrieval: Implications For Quantum Optical Networks, Billie V. Deluca

Theses and Dissertations

Quantum information and communication is the next revolution in information technology. However, communication through quantum networks will require the ability to transmit, store, and interact with photonic quantum bits (qubits). The focus of this dissertation is a theoretical description of a promising technology for storage of photonic states employing electromagnetically induced transparency (EIT). A general semiclassical model for EIT photonic storage will be developed, a key capability required for understanding the effect of storage that is independent of the photonic state being stored. This dissertation demonstrates the capability of this model to predict light pulses retrieved from EIT storage as …

Evaluating Frozen Soil Properties With Electrical Resistivity Measurement And Electro-Magnetic Induction Methods, Rui Liu

Theses and Dissertations

Electromagnetic induction was utilized in the past by the United States Army Corps of Engineers as a method of detecting unexploded ordinance, while it has the potential to act as a novel method of investigating frozen soils in cold regions. In this study, we performed lab-scale 1D electrical resistivity measurements under freeze-thaw circumstances on frost-susceptible soils with varied soil properties. We implemented an empirical model from our experiments into a COMSOL finite element model at both laboratory and field scales to simulate soil electrical resistivity response under both short-term and long-term sub-freezing conditions. Dynamic temperature-dependent soil properties, most notably unfrozen …

Performance Of Siso And Mimo Antenna Systems In Suburban And Urban Scenarios For V2i Communications At 5.9 Ghz And 28 Ghz, Oluwaseun Falade

Theses and Dissertations

As the need for Vehicle to Infrastructure (V2I) innovations increases, further research is needed to test the performance of antennas installed on vehicles in realistic scenarios including their radiation patterns and optimal location. This thesis considers realistic suburban and urban scenarios with SISO and MIMO antennas for V2I systems at 5.9 GHz and 28 GHz. The simulation is based on Ray tracing (RT) channel models to accurately model the effects of obstacles such as buildings and vehicles on the communication signals. Time-varying vehicular environments are simulated using a 3-D RT tool involving a vehicle and a base station. This research …

Preparing For V2x Deployment: Evaluating Current Anonymity Implementations, And Developing A Framework For Gauging Roadside Unit Networkability, Daniel Arnaudov Sharp

Theses and Dissertations

In this thesis we answer two questions relating to the impending deployment of V2X. We answer, "What is the state of current privacy measures implemented to prevent tracking and promote anonymity?" We answer this by showing that tracking methods used to circumvent changing IDs are possible. We also show through conservative calculations that this problem will not go away on its own and requires direct effort. We also answer, "Is the available production V2X hardware ready for scalable deployment?" To do this we develop a framework for evaluating RSUs and many of their core functions related to deployment, scalability, and …

Designed For Better Control: Using Kinematic And Dynamic Metrics To Optimize Robot Manipulator Design, John R. Morrell

Theses and Dissertations

In the field of control theory, optimal performance is generally defined as the best possible controlled performance given a static, unchangeable plant system. However, principled design of the underlying system can make designing effective controllers easier and dramatically improve the final control performance beyond what any finely tuned controller could achieve alone. This work develops performance metrics for serial robot arms which help guide the design and optimization of the structure of the arm to achieve greater final performance. First, a kinematic (motion-based) metric called the Actuator Independence Metric (AIM) measures the uniqueness of the movement capabilities of the different …

Interaction Of Natural Convection And Real Gas Radiation Over A Vertical Flat Plate, Nathan Hale

Theses and Dissertations

This study explores natural convection heat transfer and fluid flow from a vertical plate in a radiating gas accounting for real gas spectral behavior. Finite volume techniques are used to solve the coupled nonlinear partial differential equations for mass, momentum, and energy conservation, while radiation transfer is modeled using the Discrete Ordinates finite volume finite angle method. Real gas spectral behavior is accounted for using the Rank Correlated Spectral Line Weighted-sum-of-gray-gases method. It is found that gas temperature and velocity are higher in the boundary layer, thickening the thermal and hydrodynamic boundary layers compared to the limiting case of pure …

Groundwater Resource Assessment For West Africa Using Earth Observations And Groundwater Modeling, Sergio Armando Barbosa Casas

Theses and Dissertations

Groundwater is a crucial global resource, particularly in semiarid regions where surface water is scarce. As a result, effective groundwater management is essential. However, the challenge lies in a lack of data and information for proper decision-making. This dissertation present studies related to groundwater storage changes and recharge in West Africa, using data from NASA's Gravity Recovery and Climate Experiment (GRACE) mission. In Niger, this research reveals little change in groundwater storage from 2002 to 2010 but a steep rise from 2010 to 2021, attributed partially to increased precipitation. Groundwater resources in Niger are found to be underutilized, with estimated …

Evaluating And Advancing Automated Traffic Signal Performance Measures: Statistical And Machine Learning Approaches, Bangyu Wang

Theses and Dissertations

Automated traffic signal performance measures (ATSPM) are increasingly used to collect and evaluate traffic data from signalized intersections. ATSPM provide invaluable insights into both current and historical traffic signal performance. With their adoption by over 39 state and local transportation agencies, ATSPM play a crucial role in traffic operation and maintenance. ATSPM are continually evolving, introducing new performance measures and applications tailored to the needs of various transportation agencies. However, despite their potential, several challenges require attention and resolution. The first challenge involves the underutilization of ATSPM data due to its massive volume, which can overwhelm traditional identification and prioritization …

Robust Localization And Landing For Autonomous Unmanned Aerial Vehicles In Maritime Environments, Alexander D. Jordan

Theses and Dissertations

This thesis presents methods for robust precision landing of unmanned air vehicles (UAVs) on platforms at sea. Localization methods are proposed for UAV-to-boat state estimation for systems that employ real- time kinematic (RTK) global navigation satellite system (GNSS) and vision sensors. Solutions for GNSS-only are first presented, followed by the fusion of GNSS and vision. The important problem of sensor intrinsic calibration is solved with a novel offline batch estimation approach. Hardware results are presented for all methods. Our calibration of GNSS-to-camera is shown to estimate sensor offsets with millimeter level accuracy. Localization systems are combined with custom state machines …

Early Life Drift And Environmental Effects In Nanocomposite Sensors For Biomechanics Applications, Jacob D. Carter

Theses and Dissertations

Wearable nanocomposite strain sensors are a promising technological advancement for real-time monitoring of human biomechanics. However, characterization of these sensors for biomechanical use can be complex due to factors such as creep-related resistance drift and environmental influence (humidity and temperature). The purpose of this work is to investigate and quantify these factors as well as seek to mitigate their effects. The first portion of this thesis is a study on creep-related drift of the electrical behavior of the sensors, investigating the impact of material cure levels and application of a compressive prestrain in ameliorating the observed drift. DSC testing of …

Enhancing Local Hydrological Services With The Geoglows Ecmwf Global Hydrologic Model, Jorge Luis Sanchez Lozano

Theses and Dissertations

Global hydrological models can fill crucial gaps for providing essential information on water resources management, flood and drought forecasting, and assessing the impacts of climate change. However, these models face several challenges that must be addressed to ensure their applicability at local scales. These challenges include effectively managing Big Data, proper communication, adoption, and achieving accuracy in their results. Achieving accuracy in global hydrological models is critical for acceptance in decision-making, but poses the most significant challenge due to the extensive amount of observed data required and the complexity of obtaining and preparing such data for model evaluation. In this …

Real-Time Spatial Interference Removal And Maximum Ratio Combining In Communication Systems, Adam Gary Whipple

Theses and Dissertations

Radio frequency interference (RFI) is undesired and commonplace. Using a subspace projection method to spatially remove the interference from a phased array system gives results of a 30 dB interference null rejection (INR). Unmanned systems have been developed to observe underwater activity and communicate their observations to passing aircraft. These systems are currently limited by their use of a single transmitter. The uplink can be improved by using a dual-antenna beam steering approach to maximize the signal-to-noise ratio (SNR) the aircraft receives. This approach demonstrates an increase in SNR of 3 dB when compared to a single transmitter.

Numerical Evaluation Of Forces Affecting Particle Motion In Time-Invariant Pressurized Jet Flow, Donald E. Peterson

Theses and Dissertations

This work evaluates the relative significance of forces determining the motion of a pulverized coal particle under conditions representative of a pressurized oxy-coal combustor. The gravity force and surface forces of drag, fluid stress, added mass, and Basset history are discussed and appropriate forms of these force equations are chosen, with a consideration of spherical and non-spherical drag and the Basset history kernel. Studies from the literature that emphasize specific forces are used to validate the implementation of the force equations and correlations. Modeling is based on time-averaged, one-dimensional motion of a single non-reacting particle along the centerline of a …

Continuous-Time Trajectory Estimation And Its Application To Sensor Calibration And Differentially Flat Systems, Jacob C. Johnson

Theses and Dissertations

State estimation is an essential part of any robotic autonomy solution. Continuous-time trajectory estimation is an attractive method because continuous trajectories can be queried at any time, allowing for fusion of multiple asynchronous, high-frequency measurement sources. This dissertation investigates various continuous-time estimation algorithms and their application to a handful of mobile robot autonomy and sensor calibration problems. In particular, we begin by analyzing and comparing two prominent continuous-time trajectory representations from the literature: Gaussian processes and splines, both on vector spaces and Lie groups. Our comparisons show that the two methods give comparable results so long as the same measurements …

A Polarizable Molecular Dynamics Potential For Molten Salt Property Prediction, Jared Thurgood

Theses and Dissertations

The present study attempts to find an alternate computational tool to model the complex physical interactions within the molten salt FLiNaK in a way that is both efficient and accurate. Additionally, this study seeks to describe the effects of several different types of impurities on the FLiNaK salt system. This study selects two different polarizable force fields, the AMOEBA polarizable approach and the polarizable ion model, to determine the density and the structure of the impure FLiNaK salt mixtures at typical operating temperatures in molten salt reactors (between 500-900 °C). This study conducts ab initio molecular dynamics (AIMD) simulations and …

Experimental Characterization Of Internal Wave Generation By Multiple Ridge Topographies, Natasha J. Wilson

Theses and Dissertations

Internal waves are three dimensional waves that occur in stratified fluids, where density increases with depth, such as the ocean and atmosphere. In the oceans, internal waves are continuously generated by tidal flow over subsea topography. The size and shape of the topography, as well as the stratification relative to the oscillation frequency influence the characteristics of the generated internal wave field. To advance the current understanding of how ridges on a subcritical topography changes the internal waves generated, four symmetric topographies are used with ridge numbers ranging from three to six. An additional single ridge topography is used, as …