Electrical and Computer Engineering Commons^™

Novel Control Technique For Cadmium Sulfide, Rafael Ordonez

Open Access Theses & Dissertations

Cadmium sulfide Chemical-Bath-Deposition parameters are modified to allow, for the first time, real time monitoring of cadmium ion molarity using a commercially available cadmium ion Ion-Selective-Electreode at 60°C. This modification involves alterations to typical deposition parameters that eliminate the formation of cadmium hydroxide and keep cadmium ion molarity above 10-7M. The new or atypical parameters developed are pH values below 8.9 and lower moralities for all chemicals. In order to have complexation of cadmium ion driven mainly by ammonia, parameters that minimized complexation by other chemicals are found. Cadmium acetate concentration below 2mM and ammonium acetate concentration below 10mM minimize …

Design Of An Integrated Starter-Alternator For A Series Hybrid Electric Vehicle: A Case Study In Axial Flux Permanent Magnet Machine Design, Jessica L. Colton

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

This thesis details the design of an electric machine to perform as both a starter and alternator in a series hybrid electric vehicle. The focus of the work is on practical design aspects specific to single-sided axial flux permanent magnet machines with non-overlapped windings. First, a characterization of the rotor losses in these machine types is presented through experimental validation of finite element analysis estimates. The approaches taken to model the axial flux geometry, especially in two-dimensions, are detailed, and the difficult issue of validating the finite element analysis estimates with experimental data is addressed with a prototype 24-slot, 20-pole …

Design And Simulation Of A Position Sensitive Device With Gaussian Response, Debra Erin Medina

Open Access Theses & Dissertations

Not Required

Compressive Sensing With Prior Information Applied To Magnetic Resonance Imaging, Cristiano Jacques Miosso

Open Access Theses & Dissertations

This dissertation introduces the theory of compressive sensing with prior information about a signal's sparse representation. We show, mathematically and in numerical simulations, that prior information improves signal reconstruction, in terms of number of required measurements, computation time and signal-to-noise ratios. Following, we present a set of methods for enhanced magnetic resonance imaging and tomography that can be combined with prior information, for enhanced image quality.

In developing the theory of compressive sensing with prior information, we provide a mathematical proof of the required condition (in terms of number of linear measurements) for reconstruction using the ideal approach of l0-minimization, …

Sensor Interpolation And Super Resolution Image Reconstruction Using The Optimal Recovery Framework, Veenarai Moram

Open Access Theses & Dissertations

Wireless sensor networks have the potential to benefit society in a myriad of ways, but due to constraints of sensor placement, obtaining the desired signals is not an easy problem. Retrieving the information accurately from sensors placed randomly is a challenging problem of sensor communication and signal interpolation. In this research the optimal recovery (OR) method, a deterministic framework that can use a priori bandwidth or spectral shape information, is used to interpolate from the given samples produced by sensors. In the reconstruction formulation, a worst case error signal occurs. To minimize this error, the OR method uses a norm …

Modeling Biological Structures Via Abstract Grammars To Solve Common Problems In Computational Biology, David J. Russell

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Grammars are generally understood to be the set of rules that define the relationships between elements of a language. However, grammars can also be used to elucidate structural relationships within sequences constructed from any finite alphabet. In this work abstract grammars are used to model the primary and secondary structures present in biological data. These grammar models are inferred and applied to efficiently solve various sequence analysis problems in computational biology, including multiple sequence alignment, fragment assembly, database redundancy removal, and structural prediction.

The primary structures, or sequential ordering of symbols, of biological data are first modeled with Lempel-Ziv (LZ) …

Growth And Characterization Of Silicon Carbide Thin Films Using A Nontraditional Hollow Cathode Sputtering Technique, James Huguenin-Love

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Silicon carbide (SiC) is considered a suitable candidate for high-power, high-frequency devices due to its wide bandgap, high breakdown field, and high electron mobility. It also has the unique ability to synthesize graphene on its surface by subliming Si during an annealing stage. The deposition of SiC is most often carried out using chemical vapor deposition (CVD) techniques, but little research has been explored with respect to the sputtering of SiC.

Investigations of the thin film depositions of SiC from pulse sputtering a hollow cathode SiC target are presented. Although there are many different polytypes of SiC, techniques are discussed …

Experimental Investigation Of Dielectric Barrier Impact On Breakdown Voltage Enhancement Of Copper Wire-Plane Electrode Systems, Elham Foruzan, M. Ziaee-Nezhad, A. A. Shayegani-Akmal, K. Niayesh

Department of Electrical and Computer Engineering: Dissertations, Theses, and Student Research

Non-pressurized air is extensively used as basic insulation media in medium / high voltage equipments. An inherent property of air-insulated designs is that the systems tend to become physically large. Application of Dielectric barrier can increase the breakdown voltage and therefore decrease the size of the equipments.

In this paper, the impact of dielectric barrier on breakdown voltage enhancement of a copper wire-plane system is investigated. For this purpose, the copper wire is covered with different dielectric materials. Depending on the air gap and dielectric strength of the barrier the breakdown can be initiated in the solid or gas dielectric. …

Characterizing Near-Field Circuit Board Radiation Using Crossed Electric And Magnetic Dipole Sources, Weiping He

Masters Theses

"A method to analyze radiated emissions of electronic components/circuits is presented in this thesis. More specifically the purpose of this approach is to determine an equivalent source model to accurately represent the radiated emissions produced by the circuits and components. The proposed equivalent source model, which is able to predict both electric and magnetic fields at various distances from the device under test, consists of an array of both electric and magnetic dipoles. Each source point includes two electric dipoles orientated in x and y directions and two magnetic dipoles in x and y directions"--Abstract, page iii.

Power Distribution Network Inductance Calculation, Transient Current Measurement And Conductor Surface Roughness Extraction, Fan Zhou

Masters Theses

"The first part in the thesis discussed the modeling of the mid-frequency inductance for Zpp type plane pairs in power distribution networks (PDN). It is a key step for the placement of the decoupling capacitors. This paper gives an efficient approach for the calculation of the inductance for different capacitor placements. The PEEC based formulations takes advantage of the opposite currents in the planes. This leads to compute time reductions and memory savings for both the element calculation and the matrix solve step. A formulation is used where placement of capacitors leads to only small changes in the circuit matrix. …

Data Aggregation In Wireless Sensor Networks, Priya Kasirajan

Masters Theses

"Energy efficiency is an important metric in resource constrained wireless sensor networks (WSN). Multiple approaches such as duty cycling, energy optimal scheduling, energy aware routing and data aggregation can be availed to reduce energy consumption throughout the network. This thesis addresses the data aggregation during routing since the energy expended in transmitting a single data bit is several orders of magnitude higher than it is required for a single 32 bit computation. Therefore, in the first paper, a novel nonlinear adaptive pulse coded modulation-based compression (NADPCMC) scheme is proposed for data aggregation. A rigorous analytical development of the proposed scheme …

Passive Attitude Stabilization For Small Satellites, Samir Ahmed Rawashdeh

University of Kentucky Master's Theses

This thesis addresses the problem of designing and evaluating passive satellite attitude control systems for small satellites. Passive stabilization techniques such as Gravity Gradient stabilization, Passive Magnetic Stabilization, and Aerodynamic stabilization in Low Earth Orbit utilize the geometric and magnetic design of a satellite and the orbit properties to passively provide attitude stabilization and basic pointing. The design of such stabilization systems can be done using a high fidelity simulation of the satellite and the environmental effects in the orbit under consideration to study the on-orbit behavior and the effectiveness of the stability system in overcoming the disturbance torques. The …

Theoretical Modeling And Analysis Of Ammonia Gas Sensing Properties Of Vertically Aligned Multiwalled Carbon Nanotube Resistive Sensors And Enhancing Their Sensitivity, Shripriya Darshini Poduri

University of Kentucky Master's Theses

Vertically aligned Multiwalled Carbon Nanotubes (MWCNTs) were grown in the pores of Anodized Aluminum Oxide (AAO) templates and investigated for resistive sensor applications. High Sensitivity of 23% to low concentration (100 ppm) of ammonia was observed. An equivalent circuit model was developed to understand the current flow path in the resistive sensor. This helped us in achieving high sensitivities through amorphous carbon (a-C) layer thickness tailoring by employing post-growth processing techniques like plasma etching.

A simulation model in MATLAB was developed to calculate the device resistance and the change in the sensitivity as a function of device parameters. The steady …

Design And Implementation Of The Instruction Set Architecture For Data Lars, Kalyan Ponnala

University of Kentucky Master's Theses

The ideal memory system assumed by most programmers is one which has high capacity, yet allows any word to be accessed instantaneously. To make the hardware approximate this performance, an increasingly complex memory hierarchy, using caches and techniques like automatic prefetch, has evolved. However, as the gap between processor and memory speeds continues to widen, these programmer-visible mechanisms are becoming inadequate.

Part of the recent increase in processor performance has been due to the introduction of programmer/compiler-visible SWAR (SIMD Within A Register) parallel processing on increasingly wide DATA LARs (Line Associative Registers) as a way to both improve data access …

Control And Design Considerations In Electric-Drive Vehicles, Shweta Neglur

Masters Theses

"Electric-drive vehicles have been identified as one of the promising technologies of the future. Electric-drive vehicles including fuel cell, hybrid electric, and plug-in hybrid electric vehicles have the potential to improve the fuel economy and reduce gas emissions when compared to conventional vehicles. One of the important challenges in the advancement of the electric-drive vehicles is to develop a control strategy which meets the power requirements of the vehicles. The control strategy is an algorithm designed to command the battery and the internal combustion engine of the vehicle for specific power demands. In this thesis, load follower and thermostat control …

Time-Domain Thru-Reflect-Line (Trl) Calibration Error Assessment And Its Mitigation And Modeling Of Multilayer Printed Circuit Boards (Pcb) With Complex Area Fills, Vysakh Sivarajan

Masters Theses

"Part 1 for this thesis is on the error assessment of a time-domain (t-TRL) calibration technique. Application of the "Thru-Reflect-Line" (TRL) calibration to time-domain measurements of S-parameters (t-TRL) can be used for the characterization of the printed circuit boards (PCBs). However, t-TRL calibrated results still have deviations from the reference frequency-domain vector network analyzer (VNA) calibrated results. There are two main sources of errors in the t-TRL calibration. They are random errors, such as an additive noise and jitter, and systematic errors associated with cables, connectors, and port mismatches. This work addresses these two types of errors by proper selection …

Fault Testing Quantum Switching Circuits, Marek Perkowski, Jacob Biamonte

Electrical and Computer Engineering Faculty Publications and Presentations

Test pattern generation is an electronic design automation tool that attempts to find an input (or test) sequence that, when applied to a digital circuit, enables one to distinguish between the correct circuit behavior and the faulty behavior caused by particular faults. The effectiveness of this classical method is measured by the fault coverage achieved for the fault model and the number of generated vectors, which should be directly proportional to test application time. This work address the quantum process validation problem by considering the quantum mechanical adaptation of test pattern generation methods used to test classical circuits. We found …

Leadership, Libraries, Leed For The Future, Kathryn S. Ames, Greg Heid

Georgia Library Quarterly

The article discusses the use of Leadership in Energy and Environmental Design (LEED) principles in the design of the modern public library. It is stated that an LEED-certified library will have lower costs in energy, systems replacement and maintenance through the use of light-emitting diode (LED) lighting and efficient heating and air conditioning, but that due to special materials, the up-front expense is higher. The inspection of the facility throughout its construction is also noted.

Robust Frequency-Domain Turbo Equalization For Multiple-Input Multiple-Output (Mimo) Wireless Communications, Jian Zhang

Doctoral Dissertations

"This dissertation investigates single carrier frequency-domain equalization (SC-FDE) with multiple-input multiple-output (MIMO) channels for radio frequency (RF) and underwater acoustic (UWA) wireless communications. It consists of five papers, selected from a total of 13 publications. Each paper focuses on a specific technical challenge of the SC-FDE MIMO system. The first paper proposes an improved frequency-domain channel estimation method based on interpolation to track fast time-varying fading channels using a small amount of training symbols in a large data block. The second paper addresses the carrier frequency offset (CFO) problem using a new group-wise phase estimation and compensation algorithm to combat …

Computational Intelligence Methods In Wireless Sensor Networks, Raghavendra V. Kulkarni

Doctoral Dissertations

"Wireless sensor networks (WSNs) are networks of autonomous nodes that sense, compute and communicate in order to monitor an environment collectively. Ad hoc deployment, dynamic environment and resource constraints in nodes need to be considered while addressing WSN challenges such as deployment, localization, routing and scheduling. Adaptive mechanisms that exhibit intelligent behavior in complex and dynamic environments are desirable to address these challenges. The potential of computational intelligence ( CI) based approaches for addressing WSN challenges is investigated in this study. Contributions of this dissertation are in the following three areas: critical literature analysis, new architectures and approaches, and new …