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Full-Text Articles in Engineering

Development Of The Impedance-Based Arc-Flash Determination Device (Iadd), Timothy Smith Dec 2007

Development Of The Impedance-Based Arc-Flash Determination Device (Iadd), Timothy Smith

All Theses

This thesis entitled, 'Development of the Impedance based Arc-Fault Determination Device (IADD)' details the development of a testing device that, when attached to an electrical node on the power system and through observations on voltage, current and phase shift with a step load change, determines the effective Thevenin or Norton impedance at the point of test. This thesis includes discussion of the theory and design process that enables the determination of an equivalent circuit, software development using National Instruments' LabView software development package and suggestions for future development.
The purpose of this thesis is to produce a device that can …


Fabrication, Electrical Characterization, And Annealing Of Al/, Cu/, And Au/4h-Sic Schottky Diodes, Nikhil Karkhanis Dec 2007

Fabrication, Electrical Characterization, And Annealing Of Al/, Cu/, And Au/4h-Sic Schottky Diodes, Nikhil Karkhanis

All Theses

Schottky diodes were fabricated on n-type 4H-SiC with Nickel ohmic contacts and Aluminum, Copper, and Gold Schottky contacts. An improved and revised fabrication process was developed in the course of this research project. The Schottky diodes were electrically characterized using I-V and C-V measurements to extract electrical parameters which include Schottky barrier height, ideality factor, the diode series resistance, and substrate doping density. Al/4H-SiC and Au/4H-SiC were annealed at 600¼C and 500¼C respectively to improve the Schottky parameters. Schottky barrier height was raised and the ideality factor was reduced in both cases. Significant improvement was observed in the ideality factor …


Wafer Probe And Package Test Failure Analysis, Deepa Kalva Dec 2007

Wafer Probe And Package Test Failure Analysis, Deepa Kalva

All Theses

In recent years, NAND flash memory has gained a lot of momentum in the semiconductor industry and has become an ideal choice for many consumer and communication products. One of the key elements in the successful production of NAND flash memory is to incorporate elaborate testing methods to ensure functionality and reliability before the part reaches the customer. This in turn necessitates the evaluation and understanding of different failure mechanisms, and the development of methodologies to correct problems.
In this thesis, failure analysis was performed on NAND flash memory at wafer and package level. This involved massive data collection and …


Distance Estimation Between Transceivers Over Short Distances, Karsten Lowe Dec 2007

Distance Estimation Between Transceivers Over Short Distances, Karsten Lowe

All Theses

Three methods for determining distances between a user and a fixed coordinate system are considered. One system is based on 802.11g packet communications, another on HF radio carrier frequency interference, and the final system on a signal transmitted over a radio channel. Emphasis is placed on the use of these systems in indoor, building-sized environments. Tests are performed to examine the effectivness and potential of these methods. None of the suggested methods are determined to be usable. Reasons for their failure are examined.


Formulation Of Integral Equations Using Analytic Green's Functions In Elliptic Cylindrical And Prolate Spheroidal Coordinates, Adam Schreiber Dec 2007

Formulation Of Integral Equations Using Analytic Green's Functions In Elliptic Cylindrical And Prolate Spheroidal Coordinates, Adam Schreiber

All Theses

It is desired to develop and present techniques, using analytic Green's functions in elliptic cylindrical coordinates and in prolate spheroidal coordinates, for formulating integral equations for physically practicable structures and sources. Equivalent models for two structures are introduced which serve as guides in the derivation of analytic Greens functions, comprising special functions and satisfying required boundary conditions. Expressions for needed field components are represented in terms of integrals of Greens functions times unknowns, and integral equations follow from the proper relationships among sources and field components needed to satisfy Maxwell's equations.


Load Shedding Algorithm Using Voltage And Frequency Data, Poonam Joshi Dec 2007

Load Shedding Algorithm Using Voltage And Frequency Data, Poonam Joshi

All Theses

Under frequency load shedding schemes have been widely used, to restore power system stability post major disturbances. However, the analysis of recent blackouts suggests that voltage collapse and voltage-related problems are also important concerns in maintaining system stability. For this reason, both frequency and voltage need to be taken into account in load shedding schemes. The research undertaken here considers both parameters in designing a load shedding scheme to determine the amount of load to be shed and its appropriate location. An introduction about the need for a load shedding scheme and the purpose of doing research on this particular …


Design Of Alu And Cache Memory For An 8 Bit Alu, Pravin Chander Chandran Dec 2007

Design Of Alu And Cache Memory For An 8 Bit Alu, Pravin Chander Chandran

All Theses

The design of an ALU and a Cache memory for use in a high performance processor was examined in this thesis. Advanced architectures employing increased parallelism were analyzed to minimize the number of execution cycles needed for 8 bit integer arithmetic operations. In addition to the arithmetic unit, an optimized SRAM memory cell was designed to be used as cache memory and as fast Look Up Table.
The ALU consists of stand alone units for bit parallel computation of basic integer arithmetic operations. Addition and subtraction were performed using Kogge Stone parallel prefix hardware operating at 330MHz. A high performance …


Enterprise Security Analysis Including Denial Of Service Countermeasures, Chinar Dingankar Aug 2007

Enterprise Security Analysis Including Denial Of Service Countermeasures, Chinar Dingankar

All Theses

Computer networks are the nerve systems of modern enterprises. Unfortunately, these networks are subject to numerous attacks. Safeguarding these systems is challenging. In this thesis we describe current threats to enterprise security, before concentrating on the Distributed denial of Service (DDoS) problem.
DDoS attacks on popular websites like Amazon, Yahoo, CNN, eBay, Buy, and the recent acts of war using DDoS attacks against NATO ally Estonia [1] graphically illustrate the seriousness of these attacks. Denial of Service (DoS) attacks are explicit attempts to block legitimate users' system access by reducing system availability [2]. A DDoS attack deploys multiple attacking entities …


Pursuit-Evasion With Acceleration, Sensing Limitation, And Electronic Counter Measures, Jing-En Pang Aug 2007

Pursuit-Evasion With Acceleration, Sensing Limitation, And Electronic Counter Measures, Jing-En Pang

All Theses

Abstract: The use of game theory to analyze the optimal behaviors of both pursuers and evaders originated with Isaac's work at the Rand Corporation in the 1950's. Although many variations of this problem have been considered, published work to date is limited to the case where both players have constant velocities. In this thesis, we extend previous work by allowing players to accelerate. Analysis of this new problem using Newton's laws imposes an additional constraint to the system, which is the relationship between players' velocities and allowed turning radius. We find that analysis of this relationship provides new insight into …


Fabrication And Characterization Of Cu/4h-Sic Schottky Diodes, Ruth Solomon Aug 2007

Fabrication And Characterization Of Cu/4h-Sic Schottky Diodes, Ruth Solomon

All Theses

Copper Schottky contacts to n-type 4H Silicon Carbide with nickel ohmic contacts were fabricated. The electrical and physical characteristics of these Schottky diodes were analyzed and the results are presented. I-V measurements revealed two sets of characteristics, one indicating nearly ideal Schottky behavior and the other exhibiting regions with two barrier heights. The reason for this observed phenomenon was studied and attributed to the in-homogeneity of the Silicon Carbide surface. The I-V and C-V characteristics were used to extract the electrical parameters, which include barrier height, ideality factor, reverse saturation current density, and doping concentration. The measured barrier height was …


A Study Of Estimation Techniques And Of Mechatronic System Design And Testing, Brett Castelloe Aug 2007

A Study Of Estimation Techniques And Of Mechatronic System Design And Testing, Brett Castelloe

All Theses

This thesis is a collection of two projects that the author worked on during his master's studies at Clemson University. The first project--adaptive camera calibration--involves the design and simulation of an estimator for the calibration parameters of a camera. The second project--basket drive wear testing--includes the design of a test plan for measuring wear on a mechatronic system.


Transmission Gate Based Dual Rail Logic For Differential Power Analysis Resistant Circuits, Srinidhi Narasimha Char Aug 2007

Transmission Gate Based Dual Rail Logic For Differential Power Analysis Resistant Circuits, Srinidhi Narasimha Char

All Theses

Cryptographic devices with hardware implementation of the algorithms are increasingly being used in various applications. As a consequence, there is an increased need for security against the attacks on the cryptographic system. Among various attack techniques, side channel attacks pose a significant threat to the hardware implementation. Power analysis attacks are a type of side channel attack where the power leakage from the underlying hardware is used to eavesdrop on the hardware operation. Wave pipelined differential and dynamic logic (WDDL) has been found to be an effective countermeasure to power analysis. This thesis studies the use of transmission gate based …


Performance Of Serial, Matched-Filter Packet Acquisition Algorithms With A Preamble-Sequence Acceptance Criterion, Javier Schloemann Aug 2007

Performance Of Serial, Matched-Filter Packet Acquisition Algorithms With A Preamble-Sequence Acceptance Criterion, Javier Schloemann

All Theses

In this thesis, we consider two methods to improve the acquisition performance of a packet radio system that uses serial, matched-filter acquisition: an adaptive acquisition threshold, and an acceptance criterion for the system's preamble sequences. Each packet transmission includes a fixed-length acquisition preamble, and the preamble sequence used in packet transmissions is changed at predetermined times based on a sequence-generation algorithm. It is shown that acquisition performance depends largely on the sidelobe energy of the preamble sequence, the acquisition threshold, and the signal-to-noise ratio.
The first method uses a threshold-scaling technique to account for the variation in the signal-to-noise ratio. …


An Investigation Of Nonlinear Estimation And System Design For Mechatronic Systems, Tim Hughes May 2007

An Investigation Of Nonlinear Estimation And System Design For Mechatronic Systems, Tim Hughes

All Theses

This thesis is a collection of two projects in which the author was involved during his master's degree program. The first project involves the estimation of 3D Euclidean coordinates of features from 2D images. A 3D Euclidean position estimation strategy is developed for a static object using a single moving camera whose motion is known. This Euclidean depth estimator has a very simple mathematical structure and is easy to implement. Numerical simulations and experimental results using a mobile robot in an indoor environment are presented to illustrate the performance of the algorithm. The second section describes the design of a …


Software Development For Mechatronics Systems: Simulation Of Multiple Uav Navigation And Device Driver Interface For The Q4 Data Acquisition Card, Ninad Pradhan May 2007

Software Development For Mechatronics Systems: Simulation Of Multiple Uav Navigation And Device Driver Interface For The Q4 Data Acquisition Card, Ninad Pradhan

All Theses

Mechatronics systems are often a close interleaving of different aspects of hardware, software, control and mechanical design. Two such aspects are delved into in greater detail for this thesis, both related to software development.
Simulations are used to know the practical conditions under which a control design is effective. The system simulated in this case was a multiple vehicle system, where the vehicles navigated from source to a destination configuration avoiding two different kinds of obstacles.
Post simulation, a system is implemented using hardware and tested using an experimental setup. Data Acquisition Boards such as the Quanser Q4 are used …


An Efficient Analysis Of Vertical Dipole Antennas Above A Lossy Half-Space , Yongfeng Huang May 2007

An Efficient Analysis Of Vertical Dipole Antennas Above A Lossy Half-Space , Yongfeng Huang

All Theses

The electromagnetic modeling of radiation by vertical dipole antennas above a lossy half-space has become an important subject due to many applications where these dipoles are involved. The modeling often encounters Sommerfeld-type integrals that are normally highly oscillatory with poor convergence. Recently, an efficient computation of the electric field radiated by an infinitesimal electric dipole above a lossy half-space has been reported, in which the Sommerfeld-type integrals are reduced to rapidly-converging integrals. Taking advantage of such efficiently-calculated electric field and using it as the Green's function, in this thesis, an electric field integral equation (EFIE) is formulated for the analysis …


Extrapolation Of Time And Frequency Responses Of Resonant Antennas Using Damped Sinusoids And Orthogonal Polynomials, James Frye May 2007

Extrapolation Of Time And Frequency Responses Of Resonant Antennas Using Damped Sinusoids And Orthogonal Polynomials, James Frye

All Theses

An extrapolation technique is presented which reduces the computational demands of obtaining a wide-band electromagnetic response from a resonant antenna using traditional computational methods. It has been shown that a wide-band response can be extrapolated by fitting early-time and low-frequency data as a summation of orthogonal polynomials. However, because the polynomials provide compact time support, representation of long time responses intrinsic to resonant structures in practice proves inefficient and can lead to numerical instabilities. This thesis outlines incorporating damped sinusoids to efficiently and reliably extrapolate time and frequency responses of resonant antennas due to a wide-band source. A genetic algorithm …


Soar Checkers - An Intelligent Checkers Playing Agent In Soar, Jithu Menon May 2007

Soar Checkers - An Intelligent Checkers Playing Agent In Soar, Jithu Menon

All Theses

The classic board game of checkers is ideally suited for research in AI game-playing programs or agents. The objective behind Soar Checkers is to investigate if it is possible to create an agent-based game playing system that would beat novices with ease and at least challenge advanced novice to intermediate-level players by designing a rules-based expert system whose knowledge base consists of nothing more than the rules of checkers, and a set of guidelines for game-play based on good strategy. Soar was chosen as the platform for building this agent because it came built-in with features that facilitate creating rules-based …


Linear And Non-Linear Control Of A Quadrotor Uav, Andrew Neff May 2007

Linear And Non-Linear Control Of A Quadrotor Uav, Andrew Neff

All Theses

This thesis describes two controllers designed specifically for a quadrotor helicopter unmanned aerial vehicle (UAV). A linear controller and a non-linear controller are discussed for use on the quadrotor helicopter using feedback that is obtained from microelectromechanical systems and GPS.
The linear controller is an orientation based PID controller that controls the angles of the quadrotor UAV. The controller was first simulated and the results displayed graphically using FlightGear. Experiments were conducted using this controller on a DraganFlyer X-Pro quadrotor helicopter to prove the proposed method used for closing the feedback loop.
The non-linear controller is developed using Lyapunov stability …


Isomap Tracking With Particle Filter, Nikhil Rane May 2007

Isomap Tracking With Particle Filter, Nikhil Rane

All Theses

The problem of tracking an object in an image sequence involves challenges like translation, rotation, scaling, varying ambient light and occlusions. A model of an object is built off-line by making a training set with images of the object with different poses. A dimensionality reduction technique is used to capture the variations in the training images. This gives a low-dimensional representation of the data. Isometric feature mapping is the dimensionality reduction technique used to capture the true degrees of freedom in the data. Once the data is reduced to low-dimensions it forms a part of the state-vector of the object. …


On The Effects Of Estimation Error And Jitter In Ultra-Wideband Communication , Greta Grizzard May 2007

On The Effects Of Estimation Error And Jitter In Ultra-Wideband Communication , Greta Grizzard

All Theses

The opening of the 3.6 - 10.1 GHz frequency spectrum below the 'noise-floor' by the FCC in 2002 has made possible the prospect of reusing this frequency spectrum through ultra-wideband (UWB) communication. In this thesis, we compare the performance of several UWB systems in the presence of estimation error and jitter. We then develop two alternative decision schemes to combat the effect of jitter in the UWB system. Numerical results show that one of the schemes provides significantly better performance in the presence of severe jitter than maximal ratio combining and minimal degradation of performance if jitter is not present. …


Attestation-Based Remote Biometric Authentication, Thomas Polon May 2007

Attestation-Based Remote Biometric Authentication, Thomas Polon

All Theses

Migration from password and token-based authentication in distributed systems requires fundamental changes to the authentication process. A person's biometric data is not a secret, which presents a fundamental difference with other authentication methods. Matching a sample with a database template is secondary to establishing trust in the integrity of the sample. The process is similar to establishing a chain of custody for judicial evidence. In computer systems this is accomplished using attestation architectures. In this paper, a design for a secure remote biometric login system based on an attestation architecture is analyzed. The system uses a commercially available Trusted Platform …


Comparative Study Of Haptic And Visual Feedback For Kinesthetic Training Tasks, Ravikiran Singapogu Jan 2007

Comparative Study Of Haptic And Visual Feedback For Kinesthetic Training Tasks, Ravikiran Singapogu

All Theses

Haptics is the sense of simulating and applying the sense of human touch. Application of touch sensations is done with haptic interface devices. The past few years has seen the development of several haptic interface devices with a wide variety of technologies used in their design. This thesis introduces haptic technologies and includes a survey of haptic interface devices and technologies. An improvement in simulating and applying touch sensation when using the Quanser Haptic Wand with proSense is suggested in this work using a novel five degree-of-freedom algorithm. This approach uses two additional torques to enhance the three degree-of-freedom of …