Electrical and Computer Engineering Commons^™

Hyperspectral Methods Of Determining Grit Application Density On Sandpaper, Lee A. Clark

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A low cost real time method of determining the density of grit applied to sandpaper does not currently exist. This thesis will explore three methods for determining grit density from digital image data. A means to characterize the application in terms of frequency by using direct cosine transform basis images will be explored. An RX detector algorithm to characterize the image background will be tested. A linear unmixing methodology will be developed that characterizes the proportion of glue and grit present in each hyperspectral pixel vector.

Sulfur-Tolerant Catalyst For The Solid Oxide Fuel Cell, Bozeman Joe Frank Iii

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JP-8 fuel is easily accessible, transportable, and has hydrogen content essential to solid oxide fuel cell (SOFC) operation. However, this syngas has sulfur content which results in a poisonous hydrogen sulfide that degrades electrochemical activity and causes complete SOFC failure in some cases. The goal is to synthesize and verify a cost-effective, catalyst supported on cerium oxide that either stabilizes ionic conductivity in the presence of hydrogen sulfide and/or is highly sulfur-resistant. After thorough computational analysis, it was concluded that the platinum-copper skin catalyst was the most cost-effective, sulfur-resistant catalyst. Experimental synthesis of copper, platinum, and platinum-copper skin catalysts supported …

Fault Diagnosis Of Vehicular Electric Power Generation And Storage, Hithesh Sanjiva Uliyar

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Automotive vehicles are becoming increasingly dependent on electric power, and this trend will accelerate. The health of the vehicular electric power generation and storage (EPGS) system is crucial to enhance vehicle safety, fuel economy, and customer satisfaction.

In this research, a state-of-health (SOH) monitoring method is developed for automotive EPGS system, focusing on alternator related faults. Parity relations, characterizing the correlation among EPGS system signals under normal operating conditions, are generated using principal/minor component analysis techniques. Based on a design of structured residuals, the faults under consideration, including shorted diodes, belt slippage, and regulator fault, are successfully detected and isolated. …

Design Of Ultra High Speed Flash Adc, Low Power Folding And Interpolating Adc In Cmos 90nm Technology, Vinayashree Hiremath

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In recent years, signal processing has gained ample significance making high speed and low voltage analog-to-digital converters (ADC) inevitable in numerous applications. Two such ADCs designed in CMOS 90nm technology are presented in this thesis.

In flash ADC, thermometer to binary encoder often becomes bottleneck in achieving high speed. An encoder deploying new CMOS logic, with fewer transistors through the use of pseudo-dynamic circuits is described. This 4 bit flash ADC operates at 5GHz with an average power dissipation of 1.3mW.

Folding and interpolation significantly reduces the number of comparators used in flash architecture. A 6 bit 400MSPS low power …

Multi-User Signal Classification Via Cyclic Spectral Analysis, Brent Edward Guenther

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This research develops and evaluates several different methods for multi-user signal classification via cyclic spectral analysis. The first method uses the spectral correlation function (SCF) through temporal smoothing with the use of higher order cyclic statistics (HOCS) to allow for modulation classification. The second method uses the cyclic temporal cumulant function (CTCF) and the spectral coherence function (SOF) through frequency smoothing. Using a feature-based pattern recognition technique with the SOF can not only determine the number of signals present in the received signal, but can also give signal parameter estimation and group classification performance. The last method conducts further modulation …

Design Of Hf Forward Transformer Including Harmonic Eddy Current Losses, Dhivya Ammanambakkam Nagarajan

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Pulse Width Modulated (PWM) Forward DC-DC converter is a buck-derived isolated power converter which is used extensively in low power to medium power applications. Satisfactory operation of the transformer utilized in forward converter plays a crucial role in the overall operation of the forward converter. Hence detailed analysis pertaining to design of forward transformer is important. The forward transformer is unique as the magnetizing inductance is not required to store magnetic energy. Additionally, the forward transformer has a tertiary winding, which is required to reset the core and to prevent core saturation. This adds to the complexity of design and …

Characterization Of An Inductively Coupled Plasma Produced In Argon At 13.56 Mhz., Lim Ai Nuan

Student Works (2010-2019)

The electrical and plasma characteristics of radio frequency (13.56 MHz) inductively coupled argon plasma (RF ICP) were studied in this project. On the electrical breakdown properties, the breakdown voltage has a general appearance of Paschen’s curve and the minimum is achieved at 0.1 mbar. After ignition, two modes of discharge exist, namely, the E mode at low RF power and H mode at high RF power. Mode transition that occurs is accompanied by abrupt changes in both electrical and plasma characteristics. Hysteresis is observed in the mode transitions and has a minimum at 0.1 mbar. The resistance reflected into the …

Performance Analysis Of Srcp Image Based Sound Source Detection Algorithms, Praveen Reddy Nalavolu

University of Kentucky Master's Theses

Steered Response Power based algorithms are widely used for finding sound source location using microphone array systems. SRCP-PHAT is one such algorithm that has a robust performance under noisy and reverberant conditions. The algorithm creates a likelihood function over the field of view. This thesis employs image processing methods on SRCP-PHAT images, to exploit the difference in power levels and pixel patterns to discriminate between sound source and background pixels. Hough Transform based ellipse detection is used to identify the sound source locations by finding the centers of elliptical edge pixel regions typical of source patterns. Monte Carlo simulations of …

Issues Related To The Numerical Implementation Of A Sparse Method For The Solution Of Volume Integral Equations At Low Frequencies, Kiran Arcot

University of Kentucky Master's Theses

Computational electromagnetic modeling involves generating system matrices by discretizing integral equations and solving the resulting system of linear equations. Many methods of solving the system of linear equations exist and one such method is the factorization of the matrix using the so called local-global solution (LOGOS) modes. Computer codes to perform the discretization of the integral equations, filling of the matrix, and the subsequent LOGOS factorization have previously been developed by others. However, these codes are limited to complex double precision arithmetic only.

This thesis extends and expands the existing computer by creating a more general implementation that is able …

Accelerated Aging Of Mwcnt Filled Electrically Conductive Adhesives, Ashwanth Reddy Vangala

University of Kentucky Master's Theses

Electrically conductive adhesives (ECA) are discussed and studied with everincreasing interest as an environmentally friendly alternative to solder interconnection in microelectronics circuit packaging. They are used to attach surface mount devices (SMD), Integrated Circuits (IC) and Flip chips in electronic assembly. The use of ECAs brings some benefits like flexibility, mild processing conditions and process simplicity. Multi walled carbon nanotubes (MWCNT) are used instead of metal fillers because of their novel properties such as light weight, high aspect ratio, corrosion resistant, reduced processing temperature, lead free, good electrical conduction and mechanical strength.

The purpose of the present work is to …

Genetic Algorithm Controlled Common Subexpression Elimination For Spill-Free Register Allocation, Shashi Deepa Arcot

University of Kentucky Master's Theses

As code complexity increases, maxlive increases. This is especially true in the case of the Kentucky If-Then-Else architecture proposed for Nanocontrollers. To achieve low circuit complexity, computations are decomposed to bit-level operations, thus generating large blocks of code with complex dependence structures. Additionally, the Nanocontroller architecture allows for only a small number of single bit registers and no extra memory.

The assumption of an infinite number of registers made during code generation becomes a huge problem during register allocation because the small number of registers and no additional memory. The large basic blocks mean that maxlive almost always exceeds the …

Comparison Of Stabilization Methods For Fixed-Speed Wind Generator Systems, Mohammod Ali, Bin Wu

Faculty Publications

Static Synchronous Compensator (STATCOM), Pitch control system, Braking Resistor (BR), and Superconducting Magnetic Energy Storage (SMES) have recently been reported as stabilization methods for fixed-speed wind generator systems. although the individual technologies are well documented, a comparative study of these systems has not been reported so far. This paper aims to fill in the gap, and provides a comprehensive analysis of these stabilization methods for fixed-speed wind generator systems. The analysis is performed in terms of transient stability enhancement, controller complexity, and cost. a novel feature of this work is that the transient stability analysis of wind generator system is …

High Frequency Vco And Frequency Divider In Vlsi 90nm Technology, Paesol Veerakitti

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A Voltage Controlled Oscillator (VCO) is essentially a tunable frequency generator. A VCO is used as a part in PLL system which is a system that generates a stable oscillating signal. As the digital electronic industry demands an ever increasing performance in speed, VCO's are required to create higher frequency signals. However, the phase noise performance of a VCO decreases as the operating frequency gets higher. The LC VCO is developed in this thesis to be used in with a tunable frequency divider as a part of a PLL system. The LC VCO structure design takes the advantage of a …

Interface Polarization Coupling In Piezoelectric-Semiconductor Ferroelectric Heterostructures, Venkata M. Voora, Tino Hofmann, M. Brandt, M. Lorenz, M. Grundmann, N. Ashkenov, H. Schmidt, Natale J. Ianno, Mathias Schubert

Department of Electrical and Computer Engineering: Faculty Publications

We present a dielectric continuum model approach for studying the electrical polarization properties of interface polarization coupled BaTiO₃, BaTiO₃-ZnO, and ZnO-BaTiO₃-ZnO thin-film structures consisting of several hundred nanometer thick layers. Our model augments the effects of electric field driven switchable polarization and depletion layer formation with spontaneous interface polarization coupling. Wurtzite-structure (piezoelectric) n-type ZnO and perovskite-structure (ferroelectric) highly insulating BaTiO₃ layers were prepared and investigated. The coupling between the nonswitchable spontaneous polarization of ZnO and the electrically switchable spontaneous polarization of BaTiO₃ causes strong asymmetric polarization hysteresis behavior. The n-type ZnO reveals …

Protein Adsorption On And Swelling Of Polyelectrolyte Brushes: A Simultaneous Ellipsometry-Quartz Crystal Microbalance Study, Eva Bittrich, Keith B. Rodenhausen Jr., Klaus-Jochen Eichhorn, Tino Hofmann, Mathias Schubert, Manfred Stamm, Petra Uhlmann

Department of Electrical and Computer Engineering: Faculty Publications

With a coupled spectroscopic ellipsometry-quartz crystal microbalance with dissipation (QCM-D) experimental setup, quantitative information can be obtained about the amount of buffer components (water molecules and ions) coupled to a poly(acrylic acid) (PAA) brush surface in swelling and protein adsorption processes. PAA Guiselin brushes with more than one anchoring point per single polymer chain were prepared. For the swollen brushes a high amount of buffer was found to be coupled to the brush-solution interface in addition to the content of buffer inside the brush layer. Upon adsorption of bovine serum albumin the further incorporation of buffer molecules into the protein-brush …

The Manifestation Of Stopping Sets And Absorbing Sets As Deviations On The Computation Trees Of Ldpc Codes, Eric T. Psota, Lance C. Perez

Department of Electrical and Computer Engineering: Faculty Publications

The error mechanisms of iterative message-passing decoders for low-density parity-check codes are studied. A tutorial review is given of the various graphical structures, including trapping sets, stopping sets, and absorbing sets that are frequently used to characterize the errors observed in simulations of iterative decoding of low-density parity-check codes. The connections between trapping sets and deviations on computation trees are explored in depth using the notion of problematic trapping sets in order to bridge the experimental and analytic approaches to these error mechanisms. A new iterative algorithm for finding low-weight problematic trapping sets is presented and shown to be capable …

The Design And Manufacture Of A Light Emitting Diode Package For General Lighting, Michael S. Krist

Master's Theses

Lighting technologies have evolved over the years to become higher quality, more efficient sources of light. LEDs are poised to become the market standard for general lighting because they are the most power efficient form of lighting and do not contain hazardous materials. Unfortunately, LEDs pose unique problems because advanced thermal management is required to remove the high heat fluxes generated by such relatively small devices. These problems have already been overcome with complex packaging and exotic materials, but high costs are preventing this technology from displacing current lighting technologies.

The purpose of this study is to develop a low-cost …

Modeling And Analysis Of High-Speed Sources And Serial Links For Signal Integrity, Siming Pan

Masters Theses

"As the computer and electronics industry moves towards higher data rates, signal integrity and electromagnetic interference (EMI) problems always present challenges for designers for high-speed data communication systems. To characterize the entire link path between transmitters and receivers, accurate models for sources, passive link path (such as traces, vias, connectors, etc), and terminations should be built before simulations either in frequency or time domain. Due to the imperfection of model, data corrections are preferred before time-domain simulations to ensure stability. Moreover, data obtained from models should be compared with measurement results to judge the level of agreement for validations. This …

Freeform Reflector Design With Extended Sources, Florian Fournier

Electronic Theses and Dissertations

Reflector design stemmed from the need to shape the light emitted by candles or lamps. Over 2,000 years ago people realized that a mirror shaped as a parabola can concentrate light, and thus significantly boosts its intensity, to the point where objects can be set afire. Nowadays many applications require an accurate control of light, such as automotive headlights, streetlights, projection displays, and medical illuminators. In all cases light emitted from a light source can be shaped into a desired target distribution with a reflective surface. Design methods for systems with rotational and translational symmetry were devised in the 1930s. …

Quantum Dot Based Mode-Locked Semiconductor Lasers And Applications, Jimyung Kim

Electronic Theses and Dissertations

In this dissertation, self-assembled InAs/InGaAs quantum dot Fabry-Perot lasers and mode-locked lasers are investigated. The mode-locked lasers investigated include monolithic and curved two-section devices, and colliding pulse mode-locked diode lasers. Ridge waveguide semiconductor lasers have been designed and fabricated by wet etching processes. Electroluminescence of the quantum dot lasers is studied. Cavity length dependent lasing via ground state and/or excited state transitions is observed from quantum dot lasers and the optical gain from both transitions is measured. Stable optical pulse trains via ground and excited state transitions are generated using a grating coupled external cavity with a curved two-section device. …