Electrical and Computer Engineering Commons^™

Stochastic Optimal Shared Control With Non-Gaussian Processes, Paul Onor

Electrical and Computer Engineering ETDs

In this paper, we propose an approach for shared control of a planar quadrotor that allows for non-Gaussian disturbance in the model and non-Gaussian variation in the pilot's control actions. We do this by constructing empirical characteristic functions for the state, inputs, and disturbance using demonstrations by a human expert. These are then used to make predictions of future states and of the system disturbance, using the first and second moments of the empirical characteristic function to estimate the mean and variance of these processes. With this method, we can extend assumptions from additive white Gaussian noise to any real-valued …

A Study On Electromagnetic Topology Optimization Using Binary Particle Swarm Algorithm, Mohammad Sazzad Hossain

Electrical and Computer Engineering ETDs

Topology optimization is a state-of-the-art tool for detecting the best material layout in a physical space to obtain certain goals. Initially developed as a structural engineering tool, it has been recently used in electromagnetics and has shown immense potential. The aim of this work is to build a framework for applying the topology optimization method in electromagnetics using a modified binary particle swarm optimization (BPSO) algorithm. In this thesis, a very classic problem of coax to waveguide transition has been considered, and a novel solution has been given using topology optimization. The steps to implementing topology optimization using BPSO have …

The Corona-To-Spark Transition And Its Dependence On Electric Field Non-Uniformity, David O. Smith

Electrical and Computer Engineering ETDs

The corona to spark transition is an important part of understanding gaseous breakdown in non-uniform fields. The degree of uniformity in the geometry determines both the onset of corona as well as the eventual spark transition. In a highly non-uniform geometry, the onset of corona precedes the development of a spark. However, in weakly non-uniform fields, corona is unable to form before it transitions into a spark. The degree of non-uniformity at which this transition occurs is known as the corona point.

An experimental setup using the point electrodes allows precise changes in field uniformity, characterizing the corona point in …

Application Of Machine Learning For Predicting Iemi Upset In Multi-Architecture Microcontrollers, Daniel S. Guillette

Electrical and Computer Engineering ETDs

Four microcontrollers were programmed to execute a simple counting program. Pulsed RF signals – also known as Intentional ElectroMagnetic Interference (IEMI) – were injected into the clock input of the microcontrollers. At the same time, the output lines were monitored to determine whether the IEMI signal altered the output of the counting program – referred to as an upset. A state-of-the-art automated testing apparatus was used to collect and process 120,960 samples of IEMI upset data. The data was used to perform a traditional upset trends study and train a series of machine learning (ML) techniques – k-Nearest Neighbors, Support …

Decentralized Intelligent Decision Making In Cyber Physical Social Systems, Nathan Patrizi

Electrical and Computer Engineering ETDs

The accelerated evolution towards jointly considering the physical, cyber, and social space is expected to dramatically increase the interest of the research and industrial community to build efficient, resilient, and secure Cyber Physical Social Systems. In this dissertation, we focus our research activities on devising decentralized intelligent decision making models, frameworks, and algorithms to support the smooth operation of Cyber Physical Social Systems. The proposed decentralized intelligent decision making models are jointly exploiting theories from the field of Economics, such as Game Theory and Contract Theory, and from the field of Computer Science, such as Reinforcement Learning concepts. Reinforcement learning …

Speaker Diarization And Identification From Single-Channel Classroom Audio Recording Using Virtual Microphones, Antonio Gomez

Electrical and Computer Engineering ETDs

Speaker identification in noisy audio recordings, specifically those from collaborative learning environments, can be extremely challenging. There is a need to identify individual students talking in small groups from other students talking at the same time. To solve the problem, we assume the use of a single microphone per student group without any access to previous large datasets for training.

This dissertation proposes a method of speaker identification using cross-correlation patterns associated to an array of virtual microphones, centered around the physical microphone. The virtual microphones are simulated by using approximate speaker geometry observed from a video recording. The patterns …

Multicarrier Modulation Using Discrete Fractional Fourier Transform, Amir Raeisi Nafchi

Electrical and Computer Engineering ETDs

The focus of the research was to investigate the application of the discrete fractional Fourier transform (DFRFT) in communication systems. We investigated the compactness of the Gauss-Hermite like eigenvectors of the DFRFT and showed how a multi-carrier modulation system could benefit from it. This led to identifying an affine DFRFT. We proved the circular convolution property for the proposed DFRFT. Using this affine transform, we were able to design an orthogonal frequency division multiplexer (OFDM) communication system. In the process of implementing the OFDM, we developed a method for fast computation of the DFRFT using the chirp-z transform. Using the …

Relativistic Magnetron Powered By Electrons In A High-Energy State, Dmitrii Andreev

Electrical and Computer Engineering ETDs

A traditional relativistic magnetron is an efficient, high-power source of cm-wave radiation. Typically, a cathode sits inside the interaction region and produces a quickly expanding cathode plasma. However, rapid radial expansion leads to unwanted frequency drift and pulse shortening. Recently, researchers at Technion, in collaboration with the University of New Mexico, proposed to use a split cathode to form a low-energy “squeezed” state by injecting electrons externally into a potential well and squeezing them with a sufficiently strong magnetic field. Technion’s long-pulse experiments achieved a low-energy state, at the output power and efficiency comparable to a physical cathode inside the …

Intra-Hour Solar Forecasting Using Cloud Dynamics Features Extracted From Ground-Based Infrared Sky Images, Guillermo Terrén-Serrano

Electrical and Computer Engineering ETDs

Due to the increasing use of photovoltaic systems, power grids are vulnerable to the projection of shadows from moving clouds. An intra-hour solar forecast provides power grids with the capability of automatically controlling the dispatch of energy, reducing the additional cost for a guaranteed, reliable supply of energy (i.e., energy storage). This dissertation introduces a novel sky imager consisting of a long-wave radiometric infrared camera and a visible light camera with a fisheye lens. The imager is mounted on a solar tracker to maintain the Sun in the center of the images throughout the day, reducing the scattering effect produced …

Prospect-Theoretic Demand Response Management In Smart Grid Systems, Sean A. Pluemer

Electrical and Computer Engineering ETDs

In smart grid systems, demand response management (DRM) permits the efficient utilization and control of electrical loads. This control is accomplished by modifying the price of electricity or by shifting peak electricity consumption to off-peak periods. This thesis proposes a DRM model composed of multiple utility companies and multiple consumers. Due to the risk caused by the users' excessive power demands, each utility company has the potential for failure. Prospect Theory principles capture the individual consumer's risk-aware behavior. As a result, a multi-leader multi-follower Stackelberg game is introduced, involving the utility companies (leaders) and consumers (followers). The Stackelberg game determines …

Relativistic Magnetron With Diffraction Output And Split Cathode, Artem Kuskov

Electrical and Computer Engineering ETDs

The relativistic magnetron with diffraction output (MDO) is one of the most efficient
microwave sources for sub-100 ns pulses. For pulse widths greater than 100 ns, the microwave production stops due to anode-cathode (A−K) gap closure. In the presence of a solid cathode, the anode and cathode plasmas expand towards each other, shorting the gap. A research team at The Technion Israel Institute of Technology proposed to replace a solid cathode with a split cathode in a magnetron with radial extraction to mitigate gap closure and maximize microwave production from a long pulse generator. Such a cathode geometry comprises an …

Analytical, Simulation, And Experimental Study Of The Generation Of Multiple Beams For Application To A Traveling Wave Tube(Twt), Khandakar Nusrat Islam

Electrical and Computer Engineering ETDs

The traveling wave tube (TWT) has been a reliable conventional vacuum electron device (VED) since the 1940s. Researchers, beginning in the late 1980s, extended the TWT to the relativistic electron beam regime to generate 100s MW power in X-band. Since the mid-1990s there has been little advancement in the field. Recently, the linear theory of a multi-stream TWT was published that showed super-exponential amplification properties. This study describes a novel technique for producing multiple electron beams with energy difference of about 4-31% with comparable currents from a single cathode at a single potential for a multi-stream TWT. This work presents …

Synthetic Aperture Optical Imaging Interferometric Microscopy With Improved Image Quality, Preyom K. Dey

Electrical and Computer Engineering ETDs

The resolution limit of optical microscopy can be extended by using Imaging Interferometric Microscopy (IIM), which uses a low numerical aperture (NA) objective lens to achieve resolution equivalent to that of a high-NA objective lens with multiple sub-images. Along with the resolution enhancement challenge, IIM often suffers from poor image quality. In this dissertation, several image quality improvement methods are proposed and verified with simulation and experimental results. Next, techniques to extend the resolution limit of IIM to ≤ 100nm using a low-NA objective lens are demonstrated. An experimental technique of using a grating coupler on …

Reconfigurable Antennas & Matching Networks For Cubesats, Marios Patriotis

Electrical and Computer Engineering ETDs

Telecommunication has rapidly evolved in the past decades, quickly becoming one of the most expansive industries, especially with the presence of new attractive eras like 5Gnetworks, automotive radars, and CubeSats. The use of miniaturized satellites such as CubeSats for cheaper and wider communication coverage has opened the possibilities for cluster satellite communication. These units exist in a continuously varying environment as much physical as electromagnetic. Hence, the establishment of a successful communication link among the space units but also ground stations becomes challenging. This new situation can be confronted with the installation of new reconfigurable antennas. These are emitting units …

Fabrication Of Oxide-Based Memristors For Neural Networks, Jamison E. Wagner

Electrical and Computer Engineering ETDs

This thesis discusses what a memristor is, how it is hypothesized to work and the fabrication work undertaken with hafnia and titania-based ultrathin oxide films. In addition, the electrical tests utilized to characterize the physical performance of the memristors including but not limited to, their IV hysteresis responses, yield rates and overall reliability. The results and discussion of this work are aimed at better understanding how fabrication of memristive devices can be further improved for future work.

Intelligent Internet Of Things Frameworks For Smart City Safety, Dimitrios Sikeridis

Electrical and Computer Engineering ETDs

The emerging Smart City ecosystem consists of a vast edge network of Internet of Things (IoT) devices that continuously interact with mobile devices carried by its citizens. In this setting, the IoT infrastructure, apart from the main communications facilitator, acts as a crowdsourcing mechanism that collects massive amounts of user data, and can support public safety applications for the Smart City. In this thesis, we design and analyze learning mechanisms that extract intelligence from crowd interactions with the wireless IoT infrastructure, and optimize its energy efficiency while operating as a public safety network. First, we deploy a multi-story facility testbed …

Investigating Operational Modes In Gallium Nitride Photoconductive Switches, Brad J. Maynard

Electrical and Computer Engineering ETDs

As switching requirements for speed, power, and efficiency become more stringent, advances in wide-bandgap (WBG) materials has enabled their use in high power switching devices. One such device, the photoconductive semiconductor switch (PCSS), while previously constructed from GaAs, shows promise using WBG Mn-doped GaN. Lateral and vertical geometries of PCSS have been produced and evaluated for operation using sub-mJ/ns regime pulsed laser incidence. At fields below 25 kV/cm, the lateral switch operates in the linear regime where modest photocurrent fitting the laser envelope is observed. Above this threshold, the switches demonstrate circuit-limited persistent conductivity (PC) current, in what is presumed …

Fast Video-Based Face Recognition In Collaborative Learning Environments, Phuong Tran

Electrical and Computer Engineering ETDs

Face recognition is a classical problem in Computer Vision that has experienced significant progress recently. Yet, face recognition in videos remains challenging. In digital videos, face recognition is complicated by occlusion, pose and lighting variations, and persons entering and leaving the scene. The goal of the thesis is to develop a fast method for face recognition in digital videos that is applicable to large datasets. Instead of the standard video-based methods that are tested on short videos, the goal of the approach is to be applicable to long educational videos of several minutes to hours, with the ultimate goal of …

Smart Energy Harvesting For Internet Of Things Networks, Fisayo Sangoleye

Electrical and Computer Engineering ETDs

In this thesis, we address the problem of prolonging the battery life of Internet of Things (IoT) nodes by introducing a smart energy harvesting framework for IoT networks supported by femtocell access points (FAPs) based on the principles of Contract Theory and Reinforcement Learning. Initially, the IoT nodes’ social and physical characteristics are identified and captured through the concept of IoT node types. Then, Contract Theory is adopted to capture the interactions among the FAPs, who provide personalized rewards, i.e., charging power, to the IoT nodes to incentivize them to invest their effort, i.e., transmission power, to report their data …

Contract-Theoretic Demand Response Management In Smart Grid Systems, Nafis Irtija

Electrical and Computer Engineering ETDs

The sheer growth of electricity demand and the rising number of electricity-hungry devices have highlighted and elevated the need of addressing the demand response management problem in residential smart grid systems. In this thesis, a novel contract-theoretic demand response management (DRM) framework in residential smart grid systems is introduced based on the principles of labor economics. The residential households produce and consume electricity, acting as dynamic prosumers. Initially, the prosumers' personal electricity generation and consumption characteristics are captured by introducing the concept of prosumers' types. Then, the prosumers' and the electricity market's profit is depicted in representative utility functions. Based …

Machine Learning Based Dynamic Power Dispatching And Smoothing Using Hybrid Energy Storage System For Renewable Energy Systems, Bhuvaneshwarr Ramalingam

Electrical and Computer Engineering ETDs

The stochastic fluctuations from Renewable Energy Resources (RER) have a great influence on power quality and off-grid communities. A combination of the different storage systems is accessible for RER generation intermittency and to bring about finest smoothing operating cycle compared to sole Energy Storage System (ESS). Additionally, energy management in Hybrid Energy Storage System (HESS) creates an uncertainty during power smoothing operation. This research materializes, an intelligent mechanism for power smoothing and dispatch with the introduction of hybridized storage that can accommodate the unpredictable behavior of RER under dynamic load. A feed-forward neural network is proposed as a power smoothing …

Compact Sealed Spark Gaps, Seth Miller

Electrical and Computer Engineering ETDs

Spark gaps have always been a good solution for high power switching. They are simple, cheap, handle a large amount of Coulomb transfer, and are more forgiving to work with compared to solid-state alternatives. Even with solid-state switching advancing a long way since the 20th century, spark gaps outperform them in terms of peak power handling capabilities, Coulomb transfer, and make them attractive for higher power systems. Most lab settings use spark gaps because the cost is low, and they can be repaired if they break or wear out as opposed to a semiconductor alternative. While this technology is great …

Spanish And English Phoneme Recognition By Training On Simulated Classroom Audio Recordings Of Collaborative Learning Environments, Mario J. Esparza Perez

Electrical and Computer Engineering ETDs

Audio recordings of collaborative learning environments contain a constant presence of cross-talk and background noise. Dynamic speech recognition between Spanish and English is required in these environments. To eliminate the standard requirement of large-scale ground truth, the thesis develops a simulated dataset by transforming audio transcriptions into phonemes and using 3D speaker geometry and data augmentation to generate an acoustic simulation of Spanish and English speech. The thesis develops a low-complexity neural network for recognizing Spanish and English phonemes (available at github.com/muelitas/keywordRec). When trained on 41 English phonemes, 0.099 PER is achieved on Speech Commands. When trained on 36 Spanish …

Artificial Intelligent Risk-Aware Autonomous Decision-Making In Resource-Constrained Computing Systems, Pavlos Athanasios Apostolopoulos

Electrical and Computer Engineering ETDs

Artificial Intelligent autonomous systems are becoming increasingly ubiquitous in daily life. Mobile devices for example provide mechanical-generated intelligent support to humans, with various degrees of autonomy, and are a key part of the recent autonomous revolution. Autonomous intelligent systems aim to understand and interact with their users in a timely manner, while many of them are characterized by constrained resources. Despite that, the average person does not act in a formulaic and risk-neutral manner but instead exhibits risk-aware attitudes when performing a task that includes sources of uncertainties. When humans make decisions, they explore their surroundings, understand the emerging risks, …

Shift Register Puf Implementation On An Fpga, Sriram Thotakura

Electrical and Computer Engineering ETDs

In this thesis, a novel shift register-based physical unclonable function (PUF), called SRP, is proposed. The PUF is implemented on an FPGA and leverages the internal delay variations introduced by within-die process variations that occur within the Look-up tables (LUTs), routing and switches of the FPGA. PUFs are designed to generate bitstrings and keys on-the-fly that are device-specific (unique), random and reproducible. PUFs eliminate the need for a specialized (secure) non-volatile memory(NVM) to store the secret keys. This reduces the total cost of chips and systems, particularly those used in the Internet of Things, where it is common for systems …

Self-Breakdown Study Of Spherical Electrodes In Air Spanning Pressures From Atmosphere To 2000 Psia, And Stress Times From Seconds To Nanoseconds, Joseph G. Felix

Electrical and Computer Engineering ETDs

In this research, a self-breakdown switch with 12.7 mm diameter spherical electrodes and a 380-micron gap was assembled and the effect of pressure and stress time on breakdown voltage and closure time were measured. Specifically, the pressure was varied from atmosphere to 2000 psia and the stress time was varied from seconds to nanoseconds. Few studies have investigated equivalent ranges of pressure and charge times on sub millimeter gap switches with electric field intensities reaching 2 MV/cm. The correlation of the parameters and switch behavior are explored in this study. In addition, the effects of humidity and electrode surface deformities …

Etched-And-Regrown Diodes On M-Plane Gan For Next Generation Power Electronic Devices, Andrew A. Aragon

Electrical and Computer Engineering ETDs

Demand for next-generation power electronic devices is driven by continually evolving requirements of power systems. Devices utilizing III-nitride materials (GaN) and vertical selective-area doped architectures are advantageous due to their wide- bandgap, thermal management, small form-factor, and current handling.

Such devices incorporate junctions at multiple crystalline planes. Thus, effects of impurity contamination and etch damage are investigated on the m-plane (10-10) of GaN. Impurites (Si, O, and C) are shown to reduce blocking voltage (~ 10² ×) and increase forward leakage current (~ 10⁴ ×) in regrown versus continuously-grown p-n diodes. Elevated deep level defects at Ec – …

A Numerical Circuit Simulation Study Of High Voltage, Multi-Pulse Transmission Lines And Spark Gap Switches, Joe Ming Ju Chen

Electrical and Computer Engineering ETDs

The design and development of high voltage, multi-pulse transmission line generators is of high interest for linear accelerator and other pulse power applications. Los Alamos National Laboratory and L3 Applied Technologies are in development and testing of a multi-pulse series pulse forming water transmission line system dubbed the Series Pulse-Line Integrated Test Stand (SPLITS). The system consists of up to four water lines in series charged by a Marx bank of total capacitance and voltage of 39nF and -600kV, respectively, to produce multiple 120ns, -300kV pulses on a matched resistive load of 5.5 . There is a need for a …

A Reconfigurable Stretchable Liquid Metal Antenna, Phase Shifter, And Array For Wideband Applications, David M. Hensley

Electrical and Computer Engineering ETDs

While liquid metals, such as mercury, have been used in electronics for quite some time, the non-toxic gallium based liquid metals have caused an increase in research for liquid metal applications. Some of the potential applications that have been previously presented range from reconfigurable antennas, strain and pressure sensors, and speakers and microphones to name a few. The focus of this work is to provide further research into the use of gallium based liquid metals as a reconfigurable antenna, a phase shifter, and an array. This is done by designing, constructing, and characterizing each of these reconfigurable liquid metal (LM) …

Side Channel Attack Counter Measure Using A Moving Target Architecture, Jithin Joseph

Electrical and Computer Engineering ETDs

A novel countermeasure to side-channel power analysis attacks called Side-channel Power analysis Resistance for Encryption Algorithms using DPR or SPREAD is investigated in this thesis. The countermeasure leverages a strategy that is best characterized as a moving target architecture. Modern field programmable gate arrays (FPGA) architectures provide support for dynamic partial reconfiguration (DPR), a feature that allows real-time reconfiguration of the programmable logic (PL). The moving target architecture proposed in this work leverages DPR to implement a power analysis countermeasure to side-channel attacks, the most common of which are referred to as differential power analysis (DPA) and correlation power analysis …