Engineering Commons^™

Enhancements To The Modified Composite Pattern Method Of Structured Light 3d Capture, Charles Joseph Casey

University of Kentucky Doctoral Dissertations

The use of structured light illumination techniques for three-dimensional data acquisition is, in many cases, limited to stationary subjects due to the multiple pattern projections needed for depth analysis. Traditional Composite Pattern (CP) multiplexing utilizes sinusoidal modulation of individual projection patterns to allow numerous patterns to be combined into a single image. However, due to demodulation artifacts, it is often difficult to accurately recover the subject surface contour information. On the other hand, if one were to project an image consisting of many thin, identical stripes onto the surface, one could, by isolating each stripe center, recreate a very accurate …

Improving Sli Performance In Optically Challenging Environments, Eric Dedrick

University of Kentucky Doctoral Dissertations

The construction of 3D models of real-world scenes using non-contact methods is an important problem in computer vision. Some of the more successful methods belong to a class of techniques called structured light illumination (SLI). While SLI methods are generally very successful, there are cases where their performance is poor. Examples include scenes with a high dynamic range in albedo or scenes with strong interreflections. These scenes are referred to as optically challenging environments.

The work in this dissertation is aimed at improving SLI performance in optically challenging environments. A new method of high dynamic range imaging (HDRI) based on …

Capacitor Switching Transient Modeling And Analysis On An Electrical Utility Distribution System Using Simulink Software, Durga Bhavani Mupparty

University of Kentucky Master's Theses

The quality of electric power has been a constant topic of study, mainly because inherent problems to it can bring great economic losses in industrial processes. Among the factors that affect power quality, those related to transients originated from capacitor bank switching in the primary distribution systems must be highlighted. In this thesis, the characteristics of the transients resulting from the switching of utility capacitor banks are analyzed, as well as factors that influence there intensities. A practical application of synchronous closing to reduce capacitor bank switching transients is presented. A model that represents a real distribution system 12.47kV from …

Synthesis And Characterization Of P-Type Copper Indium Diselenide (Cis) Nanowires Embedded In Porous Alumina Templates, Sri Harsha Moturu

University of Kentucky Master's Theses

This work focuses on a simple template assisted approach for fabricating I-III-VI semiconductor nanowire arrays. Vertically aligned nanowires of p-CIS of controllable diameter and thickness are electrodeposited, from an acidic electrolyte solution, inside porous aluminum templates using a three electrode set up with saturated calomel electrode as the reference. AAO template over ITO-glass was used as starting template for the device fabrication. The deposited CIS is annealed at different temperatures in a reducing environment (95% Ar+ 5% H₂) for 30 minutes. X-ray diffraction of the nanowires showed nanocrystalline cubic phase structures with a strong orientation in the <112> direction. …

Simulation And Control Of A Quadrotor Unmanned Aerial Vehicle, Michael David Schmidt

University of Kentucky Master's Theses

The ANGEL project (Aerial Network Guided Electronic Lookout) takes a systems engineering approach to the design, development, testing and implementation of a quadrotor unmanned aerial vehicle. Many current research endeavors into the field of quadrotors for use as unmanned vehicles do not utilize the broad systems approach to design and implementation. These other projects use pre-fabricated quadrotor platforms and a series of external sensors in a mock environment that is unfeasible for real world use. The ANGEL system was designed specifically for use in a combat theater where robustness and ease of control are paramount. A complete simulation model of …

Evaluation Of Intelligibility And Speaker Similarity Of Voice Transformation, Anusha Raghunathan

University of Kentucky Master's Theses

Voice transformation refers to a class of techniques that modify the voice characteristics either to conceal the identity or to mimic the voice characteristics of another speaker. Its applications include automatic dialogue replacement and voice generation for people with voice disorders. The diversity in applications makes evaluation of voice transformation a challenging task. The objective of this research is to propose a framework to evaluate intentional voice transformation techniques. Our proposed framework is based on two fundamental qualities: intelligibility and speaker similarity. Intelligibility refers to the clarity of the speech content after voice transformation and speaker similarity measures how well …

Effect Of A Silicon Tip On Absorption Cross Section, Field Enhancement, And Localized Surface Plasmon Resonance Of Different Sized Gold Nanoparticles Under Evanescent Wave Illumination, Gazi Mostafa Huda

University of Kentucky Master's Theses

We have numerically investigated the influence of a nanoscale silicon tip in proximity to an illuminated gold nanoparticle. We describe how the position of the high-permittivity tip and the size of a nanoparticle impact the absorption, peak electric field and surface plasmon resonance wavelength under different illumination conditions. We detail the finite element method (FEM) approach we have used for this, whereby we specify a volume excitation field analytically and calculate the difference between this source field and the total field (i.e., scattered-field formulation). We show that a nanoscale tip can locally enhance the absorption of the particle as well …

Rotate And Hold And Scan (Rahas): Structured Light Illumination For Use In Remote Areas, Eli Ross Crane

University of Kentucky Master's Theses

As a critical step after the discovery of material culture in the field, archaeologists have a need to document these findings with a slew of different physical measurements and photographs from varying perspectives. 3-D imaging is becoming increasingly popular as the primary documenting method to replace the plethora of tests and measurements, but for remote areas 3-D becomes more cumbersome due to physical and environmental constraints. The difficulty of using a 3-D imaging system in such environments is drastically lessened while using the RAHAS technique, since it acquires scans untethered to a computer. The goal of this thesis is to …

Gaze Estimation Using Sclera And Iris Extraction, Prashanth Rao Periketi

University of Kentucky Master's Theses

Tracking gaze of an individual provides important information in understanding the behavior of that person. Gaze tracking has been widely used in a variety of applications from tracking consumers gaze fixation on advertisements, controlling human-computer devices, to understanding behaviors of patients with various types of visual and/or neurological disorders such as autism. Gaze pattern can be identified using different methods but most of them require the use of specialized equipments which can be prohibitively expensive for some applications. In this dissertation, we investigate the possibility of using sclera and iris regions captured in a webcam sequence to estimate gaze pattern. …

Investigations Of Cuinte2 / Cds & Cdte / Cds Heterojunction Solar Cells, Venkatesh Gutta

University of Kentucky Master's Theses

Thin film solar cells of Copper Indium Telluride and Cadmium Sulfide junctions were fabricated on plain ITO glass slides and also on those coated with intrinsic Tin Oxide. CdS was deposited through chemical bath deposition and CIT by electrodeposition. Both compounds were subjected to annealing at temperatures between 350°C and 500°C which produced more uniform film thicknesses and larger grain sizes. The CIT/ CdS junction was characterized after performing XRD and spectral absorption of individual compounds.

Studies were also made on CdS / CdTe solar cells with respect to effect of annealing temperatures on open circuit voltages. NP acid etch, …

Compact Vision System For Monitoring Of 3d Weld Pool Surface In Pipe Welding, Alexander Phillip Maroudis

University of Kentucky Master's Theses

Human welders have long been able to monitor a weld pool and adjust welding parameters accordingly. Automated welding robots can provide consistent movement during the welding process, but lack the ability to monitor the weld pool. A vision system attached to the welding robot could provide a way to monitor the weld pool substantially faster than a human being. Previous vision systems to monitor weld pool surfaces have been developed, but their uses are limited since the system is fixed in place. The compact vision system developed in this research attaches directly to the welding torch, which provides no limitations …

Evaluating The Effectiveness Of Peak Power Tracking Technologies For Solar Arrays On Small Spacecraft, Daniel Martin Erb

University of Kentucky Master's Theses

The unique environment of CubeSat and small satellite missions allows certain accepted paradigms of the larger satellite world to be investigated in order to trade performance for simplicity, mass, and volume. Peak Power Tracking technologies for solar arrays are generally implemented in order to meet the End-of-Life power requirements for satellite missions given radiation degradation over time. The short lifetime of the generic satellite mission removes the need to compensate for this degradation. While Peak Power Tracking implementations can give increased power by taking advantage and compensating for the temperature cycles that solar cells experience, this comes at the expense …

Artificial Neural Network Based Fault Location For Transmission Lines, Suhaas Bhargava Ayyagari

University of Kentucky Master's Theses

This thesis focuses on detecting, classifying and locating faults on electric power transmission lines. Fault detection, fault classification and fault location have been achieved by using artificial neural networks. Feedforward networks have been employed along with backpropagation algorithm for each of the three phases in the Fault location process. Analysis on neural networks with varying number of hidden layers and neurons per hidden layer has been provided to validate the choice of the neural networks in each step. Simulation results have been provided to demonstrate that artificial neural network based methods are efficient in locating faults on transmission lines and …

The Application Of Discontinuous Galkerin Finite Element Time-Domain Method In The Design, Simulation And Analysis Of Modern Radio Frequency Systems, Bo Zhao

University of Kentucky Doctoral Dissertations

The discontinuous Galerkin finite element time-domain (DGFETD) method has been successfully applied to the solution of the coupled curl Maxwell’s equations. In this dissertation, important extensions to the DGFETD method are provided, including the ability to model lumped circuit elements and the ability to model thin-wire structures within a discrete DGFETD solution. To this end, a hybrid DGFETD/SPICE formulation is proposed for high-frequency circuit simulation, and a hybrid DGFETD/Thin-wire formulation is proposed for modeling thin-wire structures within a three-dimensional problem space. To aid in the efficient modeling of open-region structures, a Complex Frequency Shifted-Perfectly Matched Layer (CFS-PML) absorbing medium is …

New Accurate Fault Location Algorithm For Parallel Transmission Lines, Pramote Chaiwan

University of Kentucky Doctoral Dissertations

Electric power systems have been in existence for over a century. Electric power transmission line systems play an important role in carrying electrical power to customers everywhere. The number of transmission lines in power systems is increasing as global demand for power has increased. Parallel transmission lines are widely used in the modern transmission system for higher reliability. The parallel lines method has economic and environmental advantages over single circuit. A fault that occurs on a power transmission line will cause long outage time if the fault location is not located as quickly as possible. The faster the fault location …

Fabrication Of Mwcnt Based Gas Sensor Using Site-Selective Growth Of Nanotubes On Gold Patterned Silicon Oxide Substrate, Srikanth Durgamahanty

University of Kentucky Master's Theses

Growth confinement techniques for multi walled carbon nanotubes on Au/SiO₂ surfaces was studied and incorporated into a gas sensor design. A device framework was conceived and a sensor was built to achieve this structure. The fabrication results were analyzed using scanning electron microscopy which confirmed the achievement of highly site-selective growth of carbon nanotubes, exclusively between the interdigitated electrodes. The sensor was then evaluated for its capacitance and conductance response when exposed to NO₂ gas. Variation in sensitivities with frequency and flow rate were analyzed. A mathematical model was derived for such a device structure and the predictions …

Resource Allocation And Efficient Routing In Wireless Networks, Jianjun Yang

University of Kentucky Doctoral Dissertations

In wireless networks, devices (nodes) are connected by wireless links. An important issue is to set up high quality (high bandwidth) and efficient routing paths when one node wants to send packets to other nodes. Resource allocation is the foundation to guarantee high quality connections. In addition, it is critical to handle void areas in order to set up detour-free paths. Moreover, fast message broadcasting is essential in mobile wireless networks. Thus, my research includes dynamic channel allocation in wireless mesh networks, geographic routing in Ad Hoc networks, and message broadcasting in vehicular networks.

The quality of connections in a …

Fabrication And Study Of Molecular Devices And Photovoltaic Devices By Metal/Dielectric/Metal Structures, Bing Hu

University of Kentucky Doctoral Dissertations

A new class of electrodes with nanometer-scale contact spacing can be produced at the edge of patterned metal/insulator/metal this film structures. A key challenge is to produce insulator layers with low leakage current and have pristine metal contacts for controlled molecular contacts. Atomic layer deposition of high quality Al₂O₃ thin films onto Au electrodes was enabled by surface modification with a self-assembled monolayer of -OH groups that react with a monolayer of trimethylaluminum gas source. Ar ion milling was then used to expose the edge of the Au/dielectric/Au structure for molecular electrode contacts. The junctions are characterized …

Camera Planning And Fusion In A Heterogeneous Camera Network, Jian Zhao

Theses and Dissertations--Electrical and Computer Engineering

Wide-area camera networks are becoming more and more common. They have widerange of commercial and military applications from video surveillance to smart home and from traffic monitoring to anti-terrorism. The design of such a camera network is a challenging problem due to the complexity of the environment, self and mutual occlusion of moving objects, diverse sensor properties and a myriad of performance metrics for different applications. In this dissertation, we consider two such challenges: camera planing and camera fusion. Camera planning is to determine the optimal number and placement of cameras for a target cost function. Camera fusion describes the …

Global Change Reactive Background Subtraction, Edwin Premkumar Sathiyamoorthy

University of Kentucky Master's Theses

Background subtraction is the technique of segmenting moving foreground objects from stationary or dynamic background scenes. Background subtraction is a critical step in many computer vision applications including video surveillance, tracking, gesture recognition etc. This thesis addresses the challenges associated with the background subtraction systems due to the sudden illumination changes happening in an indoor environment. Most of the existing techniques adapt to gradual illumination changes, but fail to cope with the sudden illumination changes. Here, we introduce a Global change reactive background subtraction to model these changes as a regression function of spatial image coordinates. The regression model is …

Sensing Characteristics Of Multiwalled Carbon Nanotube (Mwcnt) Sensors Embedded In Porous Alumina Membranes, Swetha Sree Nimmagadda

Theses and Dissertations--Electrical and Computer Engineering

A theoretical model is developed for calculating the sensitivity of resistive sensors based on aligned multiwall carbon nanotubes (MWCNT) embedded in the pores of alumina membranes. Aligned MWCNTs offer more surface area as each CNT acts as a landing site for detecting gas species. The MWCNTs behave as a p-type semiconducting layer; when the bus bar contacts are placed at either end of the top surface the resistance between the contacts responds to oxidizing (resistance decreases) and reducing gases (resistance increases). The model presented in this thesis aims to understand the device resistance dependence upon the MWCNT resistance, and the …

Design And Analysis Of Macro Switched Impedance Motors, Weston C. Johnson

Theses and Dissertations--Electrical and Computer Engineering

For present day global economies energy use is the single most important criteria determining a nation’s wealth and sustainability. The global energy needs are met primarily by fossil fuels which are of finite supply. One means to extend the life span of the fossil fuel reserves has been to improve the efficiency of existing systems including generation, storage, usage etc., as a means of conservation. This dissertation investigates a motor technology that promises to complement existing conservation techniques.

Given advances in high voltage power semiconductors, manufacturing techniques and materials research this dissertation evaluates the potential of the switched impedance motor …

Control Characteristics Of An All-Digital Proportional-Integral-Derivative (Pid) Compensator, David Michael Feinauer

Theses and Dissertations--Electrical and Computer Engineering

The digitization of classical control systems presents a number of challenges and opportunities with respect to the miniaturization, distribution, reliability verification and obsolescence of both the controller and the underlying system under control. A method for the design of proportional-integral-derivative (PID) compensators realized in the form of all-digital components is presented. All-digital refers to a system implementation that is realizable with a wide range of digital logic components including discrete digital logic elements and programmable logic devices (PLDs) such as field-programmable gate arrays. The proportional, integral and derivative components of the classical PID control law were re-envisioned in terms of …

Control Of Metal Transfer At Given Arc Variables, Yi Huang

Theses and Dissertations--Electrical and Computer Engineering

Gas Metal Arc Welding (GMAW) is one of the most important welding processes in industrial application. To control metal transfer at given variables is a focus in the field of research and development in welding community.

In this dissertation, laser enhanced GMAW is proposed and developed by adding a lower power laser onto the droplet to generate an auxiliary detaching force. The electromagnetic force needed to detach droplets, thus the current that determines this force, is reduced. Wire feed speed, arc voltage, and laser intensity were identified as three major parameters that affect the laser enhanced metal transfer process and …