Electrical and Computer Engineering Commons^™

Study Of Si-Gan Photoconductive Switches Operating Modes Using Near-Ir Radiation, Nicolas Eduardo Gonzalez Padilla

Electrical and Computer Engineering ETDs

One of the most promising solid-state devices for fast switching and radio frequency generation applications is the photoconductive switch (PCSS). These devices have been thoroughly explored since the late 1980s and exhibit remarkable switching properties in gallium arsenide (GaAs). With recent advances in wide bandgap (WBG) semiconductor manufacturing processes, there has been an increasing interest in using WBG semiconductors to implement PCSS. WBG semiconductors could exhibit the same switching characteristics as GaAs while overcoming their poor power management and short lifetime under pulsed power conditions, making PCSS a reliable option in high-power applications. Gallium Nitride (GaN) has emerged as one …

Carrier Dynamics In Green Iii-Nitride Leds Using Small-Signal Electroluminescence, Xuefeng Li

Optical Science and Engineering ETDs

Solid-state lighting has achieved significant success over the past two decades, but the low quantum efficiency of green LEDs (i.e., the “green gap”) remains a barrier to full red-green-blue (RGB) displays in numerous applications. Combating efficiency reduction in longer-wavelength LEDs requires understanding the relative roles of intrinsic effects (e.g., wave-function overlap, carrier-current density relationship, phase-space filling (PSF)) vs. extrinsic effects (e.g., material degradation due to increased defect density, compositional inhomogeneities, etc.). A systematic study of the carrier dynamics in InGaN/GaN LEDs is very important for understanding the origin of the green gap and for providing solutions to improve the efficiency …

Design, Optimization, And Hardware Deployment Of A Deep Learning Model For Gps Spoofing Detection Using Gnss Satellite Receiver Protocol Data, Clarizza Morales Chacon

Electrical and Computer Engineering ETDs

The contemporary GPS infrastructure plays a vital role in advancing Position, Navigation, and Timing (PNT) applications across various sectors, including transportation, commerce, finance, and aviation. To provide a robust and authenticated infrastructure for users, it is important to develop a methodology for verifying the authenticity of satellite navigation signals, especially in civilian applications using the C/A code. This thesis explores Machine Learning (ML) techniques, focusing on the analysis of Global Navigation Satellite System (GNSS) protocol messages like UBX and NMEA to detect anomalies in receiver and satellite behavior, indicative of potential spoofing. The research demonstrates the deployment of Machine Learning …

Optimal Management Of Renewable Energy Resources To Increase Resilience Of Power Systems, Tohid Khalili

Electrical and Computer Engineering ETDs

The main goal of this dissertation is to improve the resilience of power systems using different techniques and optimization approaches regarding new technologies. Thus, several test cases with various objective functions are proposed. Voltage regulation and demand response programs are used to investigate and improve the system's financial and reliability status. In addition, COVID-19’s effect with the high presence of renewable energy resources is examined from financial, risk, and reliability points of view. Finally, a new model for the wildfire risk is proposed in a large distribution system to increase the reliability of the system with the usage of reclosers …

Characterization Analysis And Design Of Mid-Wave Infrared Iii- V-Based Type-Ii Superlattice Nbn Photodetectors For Space Applications, Alexander Timothy Newell

Electrical and Computer Engineering ETDs

The performance of the mid-wave infrared InGaAs/InAsSb nBn photodetector is investigated and its viability for space applications is assessed. Three structures are grown with unique absorber layer doping profiles via molecular beam epitaxy. Material and device characterizations are performed and analyzed to determine the effects of doping on fundamental material parameters and detector performance. Noise-equivalent irradiance is calculated to be a factor of 4x that of an ideal detector exhibiting Rule 07 dark current and 100% quantum efficiency, demonstrating high sensitivity. The structures are then irradiated with 63 MeV protons to evaluate the extent of performance degradation over the course …

Dynamic Spectrum Management In 3d Networks Inspired By Biological Systems, Jordan Anthony Patrizi

Electrical and Computer Engineering ETDs

In this thesis, the challenge of dynamic spectrum management is treated following an economic-based perspective. In particular, a novel bioinspired spectrum allocation from the Network Service Providers (NSPs) to the users is introduced, exploiting the theory of symbiosis under the free competition. The overall objective is to determine the NSPs optimal bandwidth prices to maximize their profit, while satisfying the users bandwidth needs. The aforementioned spectrum management framework is analyzed while exploiting a novel 3D network architecture consisting of High Altitude Platforms (HAPs), Unmanned Aerial Vehicles (UAVs), and ground gNBs NSPs, each one of them presenting different operational characteristics and …

Enabling Intelligent Network Management Through Multi-Agent Systems: An Implementation Of Autonomous Network System, Petro Mushidi Tshakwanda

Electrical and Computer Engineering ETDs

This Ph.D. dissertation presents a pioneering Multi-Agent System (MAS) approach for intelligent network management, particularly suited for next-generation networks like 5G and 6G. The thesis is segmented into four critical parts. Firstly, it contrasts the benefits of agent-based design over traditional micro-service architectures. Secondly, it elaborates on the implementation of network service agents in Python Agent Development Environment (PADE), employing machine learning and deep learning algorithms for performance evaluation. Thirdly, a new scalable approach, Scalable and Efficient DevOps (SE-DO), is introduced to optimize agent performance in resource-constrained settings. Fourthly, the dissertation delves into Quality of Service (QoS) and Radio Resource …

Credit Hour Analysis, Tushar Ojha, Don R. Hush, Elias S. Lopez

Electrical & Computer Engineering Technical Reports

This report presents a detailed analysis of the credit hour usage pattern of undergraduate students at the University of New Mexico (UNM) using custom analytical tools. We introduce a credit-tree framework for analyzing credit hour efficiency. This framework leverages a custom-built specialized audit tool for categorizing student credits. More specifically, student credits are assigned to one of three categories: unusable credits that do not match any degree requirement, excess credits that can be removed without changing the requirement satisfaction, and applied credits that contribute to requirement satisfaction without excess. Clearly, this enables credit analysis at the course and degree requirement …

Electromagnetic Simulations Of The Lansce Chopper Structure, Yusuf Sahin

Electrical and Computer Engineering ETDs

Particle accelerators are important for basic research as well as in applications such as ion implantation and cancer therapy. One important accelerator is the Los Alamos Neutron Science Center (LANSCE) located at Los Alamos National Laboratory (LANL) that primarily produces neutrons for research. The beam chopper simulation described here is a study to provide better modeling of this subsystem of LANSCE. A chopper is a device in which particles are intermittently sliced and directed to a target and/or experiment. The simulations in this thesis are used to analyze the correct operating parameters of the chopper. A good chopper model can …

Speaker Diarization Of Noisy Classrooms From A Single Microphone Based On An Array Of Virtual Microphones And Machine Learning, Richard Briggs

Electrical and Computer Engineering ETDs

Speaker diarization from a single microphone is extremely challenging in noisy classroom environments. A new method based on simulating a microphone array has shown promising results, while requiring very little training. It used a minimum distance classifier to identify the speaker among a list of possible speakers. This thesis investigates machine learning methods for determining the speaker. The AOLME dataset that was used contains 758 samples totaling 894.4 seconds. Each is taken from a noisy classroom environment, focusing on five speakers - any one of whom could be active in a given sample - lasting an average of 1.2 seconds. …

Wirelessly Powering A Sea Of Sensors For Perimeter Security Applications, Ian River Chavez

Electrical and Computer Engineering ETDs

his thesis presents an innovative application of Inductive Power Transfer (IPT) technology for perimeter security systems. The approach leverages the physical properties of IPT to detect intrusions by monitoring voltage changes in wirelessly powered sensor nodes, which can double as components of an intrusion detection system. Disturbances in node orientation, indicative of potential intrusions, alter the sensor node’s resonant frequency and create measurable voltage shifts. This study explores the concept in-depth, from the analysis of resonant inductive coupling in various resonant inductive modes, to the design of transmit loops, sensor nodes, and the techniques required to ensure optimum power transfer. …

Noise-Resilient And Adaptive Distributed Control Techniques For Microgrids, Seyed Iman Habibi

Electrical and Computer Engineering ETDs

This dissertation focuses on addressing the critical tasks of secondary control in microgrids, particularly in the islanding operating mode. The presence of noise in sensors and communication links necessitates the design of a noise-resilient secondary control approach. In response, this dissertation introduces the Nonlinear Generalized Minimum Variance (NGMV) control approach into the islanded AC and DC microgrid's secondary control system. The effectiveness of the proposed approach is demonstrated through MATLAB simulations. Additionally, the dissertation presents an adaptive, model-free, and data-driven control approach for secondary voltage control in AC microgrids, addressing uncertainties. By employing Unfalsified Adaptive Control (UAC), the approach selects …

Miniature, Submersible Electromagnetic Pumps Of Molten Lead And Sodium For Gen-Iv Nuclear Reactors Development, Ragai M. Altamimi

Nuclear Engineering ETDs

Heavy metals and alkali Liquid Metals are suitable coolants for Generation IV terrestrial nuclear reactors for operating at elevated temperatures for achieving plant thermal efficiency more than 40% and the thermochemical generation of hydrogen fuel. In addition, the low vapor pressure of these liquids eliminates the need for a pressure vessel and instead operates slightly below ambient pressure. A primary issue with the uses of these coolants is their compatibility with nuclear fuel, cladding and core structure materials at elevated temperatures more than 500oC. Therefore, in pile and out-of-pile test loops have been constructed or being considered for quantifying the …

Comparison Of Random Coupling Model To Stochastic Dyadic Green’S Function When Coupling To A Distributed Port, Evelyn Anne Dohme

Electrical and Computer Engineering ETDs

The Random Coupling Model (RCM) provides statistical representation of coupling between ports in a highly overmoded resonant cavity based on knowledge of radiation impedances of system ports and cavity properties. A recent variant of RCM, the Stochastic Dyadic Green’s Functions (S-DGF), provides the statistical distribution of fields in the cavity. By using Source Reconstruction Methods (SRM) to approximate equivalent surface currents, I hypothesized that the S-DGF can calculate the fields at their location, enabling a statistical estimate of the coupled power. Using nearfield radiation from simple patch antenna simulations and the SRM to estimate the equivalent fields and account for …

Adaptive Gps Antenna Array Beam Nulling Effectiveness Under Varying Antenna Element Positioning, Aadesh Neel

Electrical and Computer Engineering ETDs

Global Positioning System (GPS) is an essential part of modern life but is susceptible to same frequency jamming. GPS jamming can add excessive noise to a received low power signal and have the capability to change or completely distort information being sent through the GPS signal. Adaptive antenna arrays have long since been a solution to mitigating GPS jamming via beamnulling algorithms. However, there is little research on the effectiveness of these beamnulling algorithms under varying element positioning. In this work, an adaptive antenna array, consisting of Right-Hand Circularly Polarized (RHCP) nearly square GPS antenna elements, was constructed and tested …

Optimizing High-Performance Computing Design: The Impacts Of Bandwidth And Topology Across Workloads For Distributed Shared Memory Systems, Jonathan A. Milton

Electrical and Computer Engineering ETDs

With the complexity of high-performance computing designs continuously increasing, the importance of evaluating with simulation also grows. One of the key design aspects is the network architecture; topology and bandwidth greatly influence the overall performance and should be optimized. This work uses simulations written to run in the Structural Simulation Toolkit software framework to evaluate a variety of architecture configurations, identify the optimal design point based on expected workload, and evaluate the changes with increased scale. The results show that advanced topologies outperform legacy architectures justifying the additional design complexity; and that after a certain point increasing the bandwidth provides …

Data-Driven Porosity Prediction For Directed Energy Deposition, Georgia E. Kaufman

Electrical and Computer Engineering ETDs

Stochastic flaw formation leading to poor print quality is a major obstacle to the utility of directed energy deposition (DED), a laser and metal powder-based additive manufacturing technology for construction and repair of custom metal parts. While melt pool temperature variability is known to be a major factor in flaw formation, control schemes to decrease flaw formation are limited by a lack of physics-based models that fully and accurately describe DED. In this work, a stochastic reachability analysis with a data-driven model based on thermal images of the melt pool was conducted to determine the likelihood of violating melt pool …

Progression Of Surface Flashover In Vacuum With Polymer Insulators, Kimberly M. Faris

Electrical and Computer Engineering ETDs

In pulsed power devices, an insulator is needed to isolate the transmission line from vacuum chambers. Vacuum is used as the insulator because it contains no atoms. Since it is being used as an insulator in these pulsed power insulation systems, surface flashover in vacuum is one of the most extensively studied areas since it being the greatest constraint in providing power due to dielectrics that are not able to sustain the voltage the system is operating under. These dielectrics are used in between high voltage electrodes in various pulsed power applications as electrical insulators to limit the electric current …

Reinforcement Learning-Based Resilience And Decision Making In Cyber-Physical Systems, Fisayo Sangoleye

Electrical and Computer Engineering ETDs

Cyber-physical systems (CPS) transform how humans interact with technology by integrating sensing, computation, networking, and control with physical processes to facilitate smart services and innovative applications in our environments. Recent advances in CPS have led to rapid growth in the amount of information constantly generated by people, systems, and processes. Most of this information, however, is underutilized due to the lack of efficient information utilization and decision-making techniques. Also, the increasing interconnectivity of CPSs presents security risks that, if left unaddressed, could be highly disruptive to systems, processes, and economies. In this dissertation, we present a study and proposal of …

Modeling And Characterization Of Cmos Logic Gates Under Large Signal Rf Injection, Zahra Abedi

Electrical and Computer Engineering ETDs

This research addresses the issue of electromagnetic interference (EMI) in digital electronics, which can cause undesired behavior in active electronic components and systems. As technology advances and transistor size decreases, devices become more susceptible to EMI. In addition, as voltage is scaled down to save energy, silicon chips become more susceptible to soft errors. While there are several ways to mitigate the impact of severe EMI on digital systems, minimal electromagnetic coupling can still cause significant problems. We develop analytical models to predict device upset due to EMI. The study focuses on identifying vulnerable parameters of operation related to device …

Incentives To Learn: A Location-Based Federated Learning Model, Ryan Kilpatrick-Morrison Brown

Electrical and Computer Engineering ETDs

Federated Learning (FL) effectiveness depends, among others, on the quality and quantity of the training data and process realized at the end computing nodes. In this paper, we introduce a novel location-based federated learning model, enabled by a low-cost and fast deployable Reconfigurable Intelligent Surfaces (RIS) - based approach that allows to accurately determine the distributed computing nodes’ positions. Furthermore, in order to train a global model to support different types of smart city applications, while considering two types of servers, offering a prime and common service, respectively, under different costs, the proposed location-based FL model is complemented by an …

Machine Learning Based Prediction Models For Silicon Heterojunction Solar Cell Optimization, Rahul Jaiswal

Electrical and Computer Engineering ETDs

Silicon heterojunction solar cell of Heterojunction with Thin Intrinsic Layer (HIT) structure is a commercially available technology, and its market share will significantly increase by the next decade. With such a significant market share, any minor improvement in the device’s overall efficiency can be beneficial three folds - customer return on investment, industry revenue, and the overall carbon footprint (from manufacturing to recycling/ disposing of the device). Conventionally, device optimization for solar cells has been achieved using a hit & trial approach where multiple experiments are done to evaluate the best process conditions and device parameters. This approach has some …

Energy-Efficient Operation And Performance Optimization In Computing Systems, Nafis Irtija

Electrical and Computer Engineering ETDs

In the modern world, an expansive range of computing systems are being used, and in all of these systems, energy efficiency and performance optimization are of utmost significance. But performance optimization means different things for different computing systems. Because of their difference in nature, computing systems have different requirements for efficiency and optimization. Distributed systems such as smart-grid systems, edge-computing environments, and blockchain systems focus on the behavior of the agents. Thus, the application of network economics principles, such as Game Theory and Contract Theory, can improve the operation of these systems in a multitude of ways. On the other …

Vi Energy-Efficient Memristor-Based Neuromorphic Computing Circuits And Systems For Radiation Detection Applications, Jorge Iván Canales Verdial

Electrical and Computer Engineering ETDs

Radionuclide spectroscopic sensor data is analyzed with minimal power consumption through the use of neuromorphic computing architectures. Memristor crossbars are harnessed as the computational substrate in this non-conventional computing platform and integrated with CMOS-based neurons to mimic the computational dynamics observed in the mammalian brain’s visual cortex. Functional prototypes using spiking sparse locally competitive approximations are presented. The architectures are evaluated for classification accuracy and energy efficiency. The proposed systems achieve a 90% true positive accuracy with a high-resolution detector and 86% with a low-resolution detector.

Long-Term Human Video Activity Quantification In Collaborative Learning Environments, Venkatesh Jatla

Electrical and Computer Engineering ETDs

Research on video activity detection has mainly focused on identifying well-defined human activities in short video segments, often requiring large-parameter systems and extensive training datasets. This dissertation introduces a low-parameter, modular system with rapid inference capabilities, capable of being trained on limited datasets without transfer learning from large-parameter systems. The system accurately detects specific activities and associates them with students in real-life classroom videos. Additionally, an interactive web-based application is developed to visualize human activity maps over long classroom videos.

Long-term video activity detection in classrooms presents challenges, such as multiple simultaneous activities, rapid transitions, long-term occlusions, duration exceeding 15 …

Theory, Simulation, And Experiments On A Magnetically Insulated Transmission Line Terminated By A Bremsstrahlung Diode, Troy Clay Powell

Electrical and Computer Engineering ETDs

Foundational concepts necessary for power flow analysis of a self-magnetically insulated transmission line (MITL) are introduced in theoretical form and several developments to the theory are described. These include cold-cathode electron emission physics, self-magnetic insulation physics, self-limited MITL current, and relativistic secondary ion production from anode surfaces. Modeling these physics is performed using EMPIRE, an electromagnetic particle-in-cell code.

Self-limited MITL current theory described numerically by Pointon is developed here in analytic form and is then used to drive simulations to compare to experiments that were performed in EMPIRE. Carefully calibrated current sensors from HERMES-III experiments show good agreement with EMPIRE …

A Reconfigurable Architecture For Matrix Multiplication For Low Power Applications, Jeffrey Love

Electrical and Computer Engineering ETDs

This thesis presents a hardware architecture for performing matrix multiplication via a systolic array to reduce time complexity and power consumption. The proposed architecture, the Neural Network Accelerator (NNA), was designed in Verilog HDL to perform 8-bit multiplication to reduce the resources required to implement the NNA on low-power FPGAs. The NNA’s open architecture is designed to support radiation test for fault tolerant designs targeting space applications. Commercial hardware architecture information is not public knowledge, which led us to build our own matrix multiplication architecture so that we could later study its feasibility for space applications.

The NNA was compared …

3d Speaker Geometry Inference From Digital Video Using 2d Projective Geometry, Sebastian Alonso Janampa Rojas

Electrical and Computer Engineering ETDs

The thesis discusses the need for a 3D world model reconstruction from raw video frames using 2D projective geometry. We propose a computer-aided approach to reconstructing a 3D speaker geometry from classroom videos of students learning Python.

The proposed method uses a transformer model to detect line candidates. Once the users identify lines corresponding to three orthogonal directions, the method computes the three vanishing points and the camera matrix. The method identifies the student’s mouths based on face landmark detection. After the estimates of the projections of the students’ mouths on the table are verified by the users, the proposed …

Data-Driven Stochastic Optimal Control Using Hilbert Space Embeddings Of Distributions, Adam J. Thorpe

Electrical and Computer Engineering ETDs

Autonomous systems are increasingly being deployed in complex environments subject to real-world uncertainty. For such systems, it may be exceptionally difficult or even impossible to compute a simple mathematical model of the system--for instance due to the presence of human elements, complex mechanics or system dynamics, or learning-enabled components. Data-driven control has recently gained significant attention in this area, where observations taken from the system evolution are used to compute an implicit representation of the system that is amenable to analysis and control. However, data-driven algorithms for control present new challenges, and require new insights to enable their use. The …

Chance Constrained Stochastic Optimal Control Of Discrete Time Linear Stochastic Systems With Applications In Multi-Satellite Operations, Shawn Priore

Electrical and Computer Engineering ETDs

Stochastic disturbances arise in a variety of engineering applications. For tractability, Gaussian disturbances are often assumed. However, this may not always be valid, such as when a disturbance exhibits heavy-tailed or skewed phenomena. As autonomous systems become more ubiquitous, non-Gaussian disturbances will become more common due to the compounding effects of sensing, actuation, and external forces. Despite this, little has been done to develop formal methods that are both computationally efficient and allow for analytical assurances with non-Gaussian disturbances. Addressing convex polytopic set acquisition and non-convex collision avoidance chance constraints with quantile and moment-based reformulations, this dissertation proposes novel stochastic …