Electrical and Electronics Commons^™

G-Code Generation For Multi-Process 3d Printing, Callum Peter Bailey

Open Access Theses & Dissertations

Since the inception of stereolithography in the 1980s, interest in 3D printing has exploded, with desktop 3D printers now commercially accessible to the general public. In recent years, next-generation multifunctional technologies have been developed, which combine 3D printing with other technologies such as wire embedding, foil embedding, CNC machining, and robotic component placement, enabling complex parts to be made on a single multifunctional machine.

However, the complexity of these integrated processes exceeds the capabilities of established design tools. To this end, this Thesis aims to develop a multi-functional design solution that can automatically generate final control code for next-generation multifunctional …

A Spatially Variant Metamaterial Design Process For Transformation Electromagnetic Devices, Eric Alan Berry

Open Access Theses & Dissertations

A technique for the implementation of devices designed using transformation optics (TO) is presented using metamaterial elements arranged using spatially variant lattices. A description of transformation optics, including the design of arbitrarily shaped devices by solving Laplace's equation numerically, is discussed. Analysis of a variety of metamaterial unit cells using frequency sweeps of the unit cells with the resulting permittivity and permeability values. Metamaterial unit cells are also analyzed by the scaling of all the features of the metamaterial elements in the unit cell and calculating the permittivity and permeability. Finite- difference time domain (FDTD) and finite-difference frequency domain (FDFD) …

Performance Evaluation Of Connectivity And Capacity Of Dynamic Spectrum Access Networks, Osama Al-Tameemi

Electronic Theses and Dissertations

Recent measurements on radio spectrum usage have revealed the abundance of under- utilized bands of spectrum that belong to licensed users. This necessitated the paradigm shift from static to dynamic spectrum access (DSA) where secondary networks utilize unused spectrum holes in the licensed bands without causing interference to the licensed user. However, wide scale deployment of these networks have been hindered due to lack of knowledge of expected performance in realistic environments and lack of cost-effective solutions for implementing spectrum database systems. In this dissertation, we address some of the fundamental challenges on how to improve the performance of DSA …

Electrosensitization Assists Cell Ablation By Nanosecond Pulsed Electric Field In 3d Cultures, Claudia Muratori, Andrei G. Pakhomov, Shu Xiao, Olga N. Pakhomova

Bioelectrics Publications

Previous studies reported a delayed increase of sensitivity to electroporation (termed "electrosensitization") in mammalian cells that had been subjected to electroporation. Electrosensitization facilitated membrane permeabilization and reduced survival in cell suspensions when the electric pulse treatments were split in fractions. The present study was aimed to visualize the effect of sensitization and establish its utility for cell ablation. We used KLN 205 squamous carcinoma cells embedded in an agarose gel and cell spheroids in Matrigel. A local ablation was created by a train of 200 to 600 of 300-ns pulses (50 Hz, 300-600 V) delivered by a two-needle probe with …

A Tool For Beamforming And Real-Time Link Budget Analysis In Aeronautical Communications Using Kinematics, M. Cenk Erturk, Yasin Aksan

Electrical Engineering Faculty Publications

Aeronautical Communication (AC) systems are likely to be a part of future tiered communication network structures. Therefore maintaining a robust AC link with a minimum power burden on the host platform has a critical importance. In this paper, we analyze the AC systems from a link budget analysis point of view and define the requirements for the parameters of link budget with an emphasize on antenna gains. First, we study the link budget analysis in an AC system. Then, we present a mathematical framework to provide an end-to-end link budget analysis utilizing the platform kinematics. Finally, we present the numerical …

Using Photovoltaics To Power Electrochemical Chloride Extraction From Concrete, Sean Bond, Lynette O'Callaghan, Niall Holmes Dr., Brian Norton

Conference papers

Corrosion of embedded steel in reinforced concrete (RC) is a world-wide problem, that reduces structural performance and lifespan. Chloride attack may be a result of seawater, de-icing salts or contaminated admixtures, brought on by ingress of chlorides into the concrete. Electrochemical Chloride Extraction (ECE) is a non-destructive treatment for contaminated RC structures, that due to uncertainty of treatment times and applied current densities, is only 50% effective. It is often diesel powered has an environmental impact and often very costly due to the long treatment times. To improve the efficiency of ECE the influences of concrete resistance, cement type and …

Solid-State Transformers For Interfacing Solar Panels To The Power Grid: An Optimum Design Methodology Of A High Frequency Transformer For Dc-Dc Converter Applications, Kenny George

Inquiry: The University of Arkansas Undergraduate Research Journal

Nowadays the use of power electronic interfaces to integrate distributed generation with the power grid is becoming relevant due to the increased penetration of renewable energy sources like solar, and the continued interest to move to a smarter and more robust electric grid. Those interfaces, which also provide a voltage step-up or step-down function, are of particular interest because renewable energy sources do not always have voltages compatible with the connecting grid. Among them, the so-called “power electronic transformer” or “solid-state transformer” (SST) is the focus of significant research. Advantages such as bidirectional power flow, improved system control, reduced size, …

Supervision Of Community Based Microgrids: An Economic Model Predictive Control Approach, Francesco Tedesco, Lubna Mariam, Malabika Basu, Alessandro Casavola, Michael F. Conlon

Conference papers

Abstract— In this paper, an Economic Model Predictive Control (EMPC) approach has been presented to manage a Community-based microgrid (C-µGCC) at the pricing level. The main task is at satisfying the demand at prosumer sides and, at the same time, optimizing various µ-Grid contrasting objectives. Emphasis has been given to the operational constraints related to the components lifetime, whose satisfaction would be beneficial for the grid in that the maintenance and replacement costs would be reduced. A simulative analysis has been carried out on the basis of available measured data related to a location in Dublin, Ireland. Results show the …

Novel Two-Dimensional Devices For Future Applications, Pratik Agnihotri

Legacy Theses & Dissertations (2009 - 2024)

The scalability of field effect transistor has led to the monumental success of complementary metal-oxide-semiconductor (CMOS) technology. In the past, device scaling was not the major issue to a greater extent. Recently with current technology nodes, transistor characteristics show signs of reduced performance due to short channel effects and other issues related to device scaling. Device designers look for innovative ways to enhance the transistor performance while keeping up with device miniaturization. Successful inventions include the development of tri-gate technology, gate all around (GAA) field effect transistors, silicon-on-insulator substrate, and high-k dielectrics. These developments have enabled the device scaling that …

Development Of Iii-Sb Based Technologies For P-Channel Mosfet In Cmos Applications, Shailesh Kumar Madisetti

Legacy Theses & Dissertations (2009 - 2024)

The continuous scaling of silicon CMOS predicts the end of roadmap due to the difficulties such as that arise from electrostatic integrity, design complexities, and power dissipation. These fundamental and practical limitations bring the need for innovative design architectures or alternate materials with higher carrier transport than current Si based materials. New device designs such as multigate/gate-all-around architectures improve electrostatics while alternate materials like III-Vs such as III-As for electrons and III-Sbs for holes increase operational speed, lower power dissipation and thereby improve performance of the transistors due to their low effective mass and faster transport properties. Further, application of …

Influence Of Neural Network Training Parameters On Short-Term Wind Forecasting, Adel Brka, Yasir M. Al-Abdeli, Ganesh Kothapalli

Research outputs 2014 to 2021

This paper investigates factors which can affect the accuracy of short-term wind speed prediction when done over long periods spanning different seasons. Two types of neural networks (NNs) are used to forecast power generated via specific horizontal axis wind turbines. Meteorological data used are for a specific Western Australian location. Results reveal that seasonal variations affect the prediction accuracy of the wind resource, but the magnitude of this influence strongly depends on the details of the NN deployed. Factors investigated include the span of the time series needed to initially train the networks, the temporal resolution of these data, the …

Reduction Of Mutual Coupling In Antenna Technology Using Elliptically Shaped Metasurfaces, Gabriel Moreno

Electronic Theses and Dissertations

This thesis is devoted to the use of metasurfaces for the goals of the reduction of mutual coupling between closely spaced antennas and the increase of antenna bandwidth. This is done first using a graphene monolayer as a cloak to decrease mutual coupling and restore radiation patterns for closely spaced antennas at THz frequencies. The introduction of the graphene monolayer was also extensively studied in regards to the effect on the radiation properties of the antennas. The use of metasurfaces also has other applications, in particular with the bandwidth of antennas, where an anisotropic metasurface can be used to drastically …

Simulation Of Gan Based Mis Varactor, Bojidha Babu

Theses and Dissertations

This work deals with novel microwave switches based on III-Nitride varactors. RF switches, power limiters and other control devices are important components of various RF systems, such as wireless modules of laptops, tablets, cell phones etc., satellites communication systems, radars, multi-band wireless and aerospace communications, phased array antennas and so worth. Traditional RF switches are fabricated using pin diodes or MEMS, Si MOSFETs or GaAs HEMTs. These devices have a number of fundamental limitations. Si or GaAs based devices suffer from a low breakdown voltage and cannot handle high RF power. Pin-diodes require large forward currents and do not allow …

Applications Of Impedance Identification To Electric Ship System Control And Power Hardware-In-The-Loop Simulation, Jonathan Siegers

Theses and Dissertations

Recent advances in semiconductor technology, controls, and switching converter topologies have resulted in the increasing application of power electronics in power distribution systems. Power electronic enabled distribution systems have inspired a renewed interest in DC distribution architectures as an appealing alternative to traditional AC methods due to the significant performance and efficiency gains they offer. However, the notional power electronic based DC distribution system is a complex and extensively interconnected system consisting of multiple power converters. As a result, a number of system-level challenges related to stability arise due to interaction among multiple power converters. In addition, the power distribution …

Miniaturized Rf Components With A Novel Tunable Engineered Substrate For Wireless Communication Systems, Yujia Peng

Theses and Dissertations

There is an increasing demand for reliable sensor system capable of remote sensing and measuring interesting data. Although large communication range can be achieved, active wireless communication systems are still suboptimal in longtime applications due to their harmful battery supply. Inductively coupled passive devices, with the advantages in safe long-term implanting, structural simplicity, small fabrication footprint and low-cost production, are preferred in chronic monitoring, but little work has been done to optimize the performance of these systems, especially under some design constraints.

The model and optimization of an inductively coupled wireless pressure sensor system is presented in this dissertation. With …

High Gain Pattern Reconfigurable Antenna Arrays For Portable And Body-Centric Wireless Applications, Nowrin Hasan Chamok

Theses and Dissertations

Wireless devices such as smartphones, tablet computers, smartwatches etc. have become ubiquitous. With that, the demand for high speed data has increased tremendously. Designing antennas for such applications is challenging because of limited availability of space, shadowing or blockage from the human body, and signal loss from multipath fading. Conventional broad, fixed beam low gain antennas result in poor reception, faster battery drainage, and low data rate. Compressed footprint high gain pattern reconfigurable antenna arrays can solve these problems which is the focus of this dissertation. Two innovative high gain pattern reconfiguration techniques, the switched beam parasitic array and the …

Estimating Local Average Power In A Line-Of-Sight Indoor Channel: Spatial Sampling And Processing, Israt Jahan Disha

Theses and Dissertations

Modeling of indoor radio channels has been a dynamic area of research in recent years because of the increasing demand for indoor wireless communications. In order to efficiently deploy such indoor systems, a good knowledge of the indoor wireless channel’s characteristics are required. One important characteristic is an accurate propagation path loss model. For developing such models various measurements have been carried out. In modeling propagation path loss in complex indoor environments, accurate and fast algorithms for estimating the local mean signal level are essential; these are also of use for power control and handoff decisions. These local mean power …

Performance Evaluation And Improvement Of Wireless Amplify-And-Forward Cooperative-Based Systems Under Nodes Mobility And Imperfect Csi Estimation Impacts, Yazid Khattabi

Electronic Theses and Dissertations

Cooperative communication techniques have been introduced in wireless networks to achieve spacial diversity-gain via the readiness of multiple users (via relays) to assist a source forwarding its data to a final destination. Cooperative communication techniques have shown their capability in improving system reliability and extending coverage area, and hence, it is believable that they will act as a promising technology for the coming fifth-generation (5G). Nevertheless, most existing work reported in literature on performance studies of wireless cooperative-based systems are based on the assumptions that the multipath fading channels among systems cooperating nodes are quasi-static (i.e., fading channels coefficients are …

Study Of Novel Power Semiconductor Devices For Performance And Reliability., Karthik Padmanabhan

Electronic Theses and Dissertations

Power Semiconductor Devices are crucial components in present day power electronic systems. The performance and efficiency of the devices have a direct correlation with the power system efficiency. This dissertation will examine some of the components that are commonly used in a power system, with emphasis on their performance characteristics and reliability. In recent times, there has a proliferation of charge balance devices in high voltage discrete power devices. We examine the same charge balance concept in a fast recovery diode and a MOSFET. This is crucial in the extending system performance at compact dimensions. At smaller device and system …

Impact Of Wireless Channel Uncertainty Upon M-Ary Distributed Detection Systems., Zahra Hajibabaei Najafabadi

Electronic Theses and Dissertations

We consider a wireless sensor network (WSN), consisting of several sensors and a fusion center (FC), which is tasked with solving an $M$-ary hypothesis testing problem. Sensors make $M$-ary decisions and transmit their digitally modulated decisions over orthogonal channels, which are subject to Rayleigh fading and noise, to the FC. Adopting Bayesian optimality criterion, we consider training and non-training based distributed detection systems and investigate the effect of imperfect channel state information (CSI) on the optimal maximum a posteriori probability (MAP) fusion rules and detection performance, when the sum of training and data symbol transmit powers is fixed. Our results …

Model Selection Via Racing, Tiantian Zhang

Electronic Theses and Dissertations

Model Selection (MS) is an important aspect of machine learning, as necessitated by the No Free Lunch theorem. Briefly speaking, the task of MS is to identify a subset of models that are optimal in terms of pre-selected optimization criteria. There are many practical applications of MS, such as model parameter tuning, personalized recommendations, A/B testing, etc. Lately, some MS research has focused on trading off exactness of the optimization with somewhat alleviating the computational burden entailed. Recent attempts along this line include metaheuristics optimization, local search-based approaches, sequential model-based methods, portfolio algorithm approaches, and multi-armed bandits. Racing Algorithms (RAs) …

Design And Characterization Of System Level Electrostatic Discharge (Esd) Protection Solutions, Yunfeng Xi

Electronic Theses and Dissertations

Electrostatic Discharges (ESD) are one of the main reliability threats in modern electronics. Design, implementation, and characterization of ESD and transient protection of these modern electronics are increasingly challenging due to the process, packaging and cost constraints. Growing communication between ‘objects’ to be sensed and controlled remotely is creating opportunities for greater integration with computer systems, resulting in improved efficiency, accuracy and economic benefits across existing and emerging network infrastructures. This tendency is driving an expansion in data communication as well as industrial applications environment. To keep up with the interconnectivity expansion, the industry requires new devices to support more …

Microgrid Control And Protection: Stability And Security, Morteza Keshavarztalebi

Electronic Theses and Dissertations

When the microgrid disconnects from the main grid in response to, say, upstream disturbance or voltage fluctuation and goes to islanding mode, both voltage and frequency at all locations in the microgrid have to be regulated to nominal values in a short amount of time before the operation of protective relays. Motivated by this, we studied the application of intelligent pinning of distributed cooperative secondary control of distributed generators in islanded microgrid operation in a power system. In the first part, the problem of single and multi-pinning of distributed cooperative secondary control of DGs in a microgrid is formulated. It …

High Average Power Nanosecond Pulsed Tm:Fiber Laser For Pumping An Optical Parametric Oscillator, Ali Abdulfattah

Electronic Theses and Dissertations

Thulium-doped fiber lasers operating with wavelengths in the vicinity of 2 µm are useful for several emerging applications including generating mid-IR light via nonlinear frequency conversion. In this study we describe the design and construction of a thulium fiber laser system comprising a master oscillator and a power amplifier. The first stage is a Q-switched, thulium-doped photonic crystal fiber oscillator utilizing an acousto-optic modulator to produce 65-80 nanosecond pulses. A diffraction grating in the cavity provides wavelength tunability from 1.8 – 2µm. The oscillator produced up to 3 W of average power and 150 µJ pulse energies, corresponding to 2.3 …

Investigation Of The Effect Of Rain On Sea Surface Salinity, Andrea Santos Garcia

Electronic Theses and Dissertations

The Aquarius/SAC-D mission provided Sea Surface Salinity (SSS), globally over the ocean, for almost 4 years. As a member of the AQ/SAC-D Cal/Val team, the Central Florida Remote Sensing Laboratory has analyzed these salinity measurements in the presence of precipitation and has noted the high correlation between the spatial patterns of reduced SSS and the spatial distribution of rain. It was determined that this is the result of a cause and effect relation, and not SSS measurement errors. Thus, it is important to understand these salinity changes due to seawater dilution by rain and the associated near-surface salinity strati?cation. This …

The Concept Of Substrate Integrated E-Plane Waveguide And Circuits, Danyang Huang

All Graduate Theses, Dissertations, and Other Capstone Projects

In this thesis, a new type of substrate integrated waveguide is proposed for implementing E-plane type of waveguide circuits on printed circuit boards. obviously, these E-plane type of circuits cannot be realized by the conventional substrate integrated waveguide. The so-called substrate integrated E-plane waveguide consists of two circuit boards attached to each other. Two copper strips are inserted in between two circuit boards, where plated through holes are penetrated through them along the transmission direction. The plated through holes and copper strips altogether played as side walls of a conventional waveguide to support longitudinal and vertical currents. Simulation is carried …

A 2x2 Polarization Switchable Patch Antenna Array For Polarization Modulation, Pengfei Ji

All Graduate Theses, Dissertations, and Other Capstone Projects

This thesis introduced and investigated a new concept in the development of a 2X2 polarization switchable patch antenna array for polarization modulation. Polarization modulation is a technique to modulate digital information using different polarization of the electromagnetic wave. The existing waveform based modulation techniques are well developed and start approaching to their performance limits. Polarization modulation provides a new modulation dimension for wireless communications and can further increase data throughput. A four-port circular patch antenna is presented and investigated for the implementation of polarization modulation. It has four ports, each excites radiation of a different polarization. A single pole four …

Titan Wireless Camera Control System, Matthew J. Trowbridge, Ian Drake, Samuel Davis, Ognjen Krco

Williams Honors College, Honors Research Projects

The Titan Camera Control System is an eletromechanical device that allows the user to wirelessly control a camera’s digital operations as well as physical orientation through the use of a mobile device application. The Titan system accepts input in the form of virtual user commands on the mobile app and performs system output in the form of sending photos/video from the camera back to the app as well as changing the orientation of the camera in accordance with the user’s commands.

Roobockey "Autonomous Hockey Robot", Keith R. Martin, Troy W. Bowers, Deboshri Sadhukhan, John A. Supel

Williams Honors College, Honors Research Projects

The goal of the ROOBockey project is to design and construct a floor hockey robot that can competitively shoot a puck. The robot design quickly locates a specific beacon through the use of image processing and uses a pneumatic shooting mechanism to send a puck to a specified target. The beacons act as possible player or goal positions in a hockey game. The robot also utilizes a wireless controller device to allow a user to maneuver the robot across a hockey field.

A Lithium Battery Current Estimation Technique Using An Unknown Input Observer, Daniel Cambron

Theses and Dissertations--Electrical and Computer Engineering

Current consumption measurements are useful in a wide variety of applications, including power monitoring and fault detection within a lithium battery management system (BMS). This measurement is typically taken using either a shunt resistor or a Hall-effect current transducer. Although both methods have achieved accurate current measurements, shunt resistors have inherent power loss and often require isolation circuitry, and Hall-effect sensors are generally expensive. This work explores a novel alternative to sensing battery current by measuring terminal voltages and cell temperatures and using an unknown input observer (UIO) to estimate the battery current. An accurate model of a LiFePO_{4 …}