Electrical and Computer Engineering Commons^™

Geometric Modeling Of Non-Rigid 3d Shapes : Theory And Application To Object Recognition., Mostafa Abdelrahman

Electronic Theses and Dissertations

One of the major goals of computer vision is the development of flexible and efficient methods for shape representation. This is true, especially for non-rigid 3D shapes where a great variety of shapes are produced as a result of deformations of a non-rigid object. Modeling these non-rigid shapes is a very challenging problem. Being able to analyze the properties of such shapes and describe their behavior is the key issue in research. Also, considering photometric features can play an important role in many shape analysis applications, such as shape matching and correspondence because it contains rich information about the visual …

Charge Collection And Surface Recombination Effects In Organic Bulk Heterojunction Solar Cells., Buddika Ka. Abeyweera 1980-

Electronic Theses and Dissertations

Charge transfer and charge extraction mechanisms are two prevalent issues in the growing field of organic solar cells. Due to their complexity in nature, new methods need to be involved in addressing the fundamental properties associated with organic polymer solar cells. This dissertation has focused on developing a new method to estimate the charge collection lengths and surface recombination lengths of organic polymer solar cells. Photocurrent spectra have been analyzed systematically to observe the dependence on thickness of the active material. A red shift of the peak of the normalized photocurrent with respect to the device thickness has been further …

Motor Protection Lab Experiment Using Sel-710, Ozro Corulli

Electrical Engineering

Advancements in microprocessor based relay technology for power protection applications provide quicker response times and new methods of mitigation. This project develops a lab experiment for Cal Poly class EE444 - Power Systems Laboratory based on the Schweitzer SEL-710 motor protection relay. Learning objectives for this lab include relay setup, programming, and protection schemes for the following conditions: undervoltage, loss of phase, fault, locked rotor, and thermal overload. Today, utility companies across the globe use SEL relays for primary system protection, putting engineers familiar with their operation in high demand.

Max Operation In Statistical Static Timing Analysis On The Non-Gaussian Variation Sources For Vlsi Circuits, Abu M. Baker

UNLV Theses, Dissertations, Professional Papers, and Capstones

As CMOS technology continues to scale down, process variation introduces significant uncertainty in power and performance to VLSI circuits and significantly affects their reliability. If this uncertainty is not properly handled, it may become the bottleneck of CMOS technology improvement. As a result, deterministic analysis is no longer conservative and may result in either overestimation or underestimation of the circuit delay. As we know that Static-Timing Analysis (STA) is a deterministic way of computing the delay imposed by the circuits design and layout. It is based on a predetermined set of possible events of process variations, also called corners of …

Nonlinear Adaptive Diffusion Models For Image Denoising, Ajay Kumar Mandava

UNLV Theses, Dissertations, Professional Papers, and Capstones

Most of digital image applications demand on high image quality. Unfortunately, images often are degraded by noise during the formation, transmission, and recording processes. Hence, image denoising is an essential processing step preceding visual and automated analyses. Image denoising methods can reduce image contrast, create block or ring artifacts in the process of denoising. In this dissertation, we develop high performance non-linear diffusion based image denoising methods, capable to preserve edges and maintain high visual quality. This is attained by different approaches: First, a nonlinear diffusion is presented with robust M-estimators as diffusivity functions. Secondly, the knowledge of textons derived …

Performance Measure For Transportation Network: A Study In Travel Time Dynamics, Anuj Nayyar

UNLV Theses, Dissertations, Professional Papers, and Capstones

Arterial Performance Measurement and Monitoring is one of the leading goals of any transportation agency. The complexity of the differences between performance measures is highlighted and the various data collection methodologies are highlighted. A major performance measure that impacts end users and traffic planners is travel time. This study presents defining a mathematical system for modeling travel time. The modeling in real-time is presented and methods are proposed to evaluate it using vehicle trajectories. Also comparative results are presented between the actual sensor data sets and simulated data to study the effectiveness of the system developed.

Study Of Seat-Belt Usage In Nevada & Driver's Performance, Atul Sancheti

UNLV Theses, Dissertations, Professional Papers, and Capstones

According to the Centers for Disease Control (CDC), motor vehicle incidents has been reported to be the leading cause of the accidental deaths in the United States accounting for more than 42,000 deaths every year. Distracted driving and Driving under influence (DUI) are the major contributors to these roadway crashes. Moreover, drivers fatigue and drowsiness behind the wheel is another important factor contributing to the high fatality rate. These factors results in significant decline in the driver's abilities of perception, recognition and vehicle control.

It has also been reported by National Highway Traffic Safety Administration (NHTSA) estimated that about 292,471 …

Robust And Adaptive Attitude Control Of Spacecraft Using Solar Radiation Pressure, Lakshmi Srinivasan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Satellites in orbit are expected to maintain a preset attitude either pointing towards Earth (in case of satellites for weather) or pointing towards space for the purpose of research and exploration. The satellite as a system though is extremely nonlinear and the system parameters are not easily available. The goal of this thesis is to develop robust and adaptive control laws that can be used to control the attitude of satellites in elliptic orbits. The attitude of the satellite is controlled by the use of Solar Radiation Pressure (SRP) on the solar panels of the satellite. The SRP is basically …

On High-Performance Parallel Fixed-Point Decimal Multiplier Designs, Ming Zhu

UNLV Theses, Dissertations, Professional Papers, and Capstones

High-performance, area-efficient hardware implementation of decimal multiplication is preferred to slow software simulations in a number of key scientific and financial application areas, where errors caused by converting decimal numbers into their approximate binary representations are not acceptable.

Multi-digit parallel decimal multipliers involve two major stages: (i) the partial product generation (PPG) stage, where decimal partial products are determined by selecting the right versions of the pre-computed multiples of the multiplicand, followed by (ii) the partial product accumulation (PPA) stage, where all the partial products are shifted and then added together to obtain the final multiplication product. In this thesis, …

Scanless Fast Handoff Technique Based On Global Path Cache For Wlans, Weetit Wanalertlak, Ben Lee, Chansu Yu

Electrical and Computer Engineering Faculty Publications

Wireless LANs (WLANs) have been widely adopted and are more convenient as they are inter-connected as wireless campus networks and wireless mesh networks. However, timesensitive multimedia applications, which have become more popular, could suffer from long end-to-end latency in WLANs.This is due mainly to handoff delay, which in turn is caused by channel scanning. This paper proposes a technique called Global Path-Cache (GPC) that provides fast handoffs in WLANs.GPC properly captures the dynamic behavior of the network andMSs, and provides accurate next AP predictions to minimize the handoff latency. Moreover, the handoff frequencies are treated as time-series data, thus GPC …

Snail Algorithm For Task Allocation In Mesh Networks, Bartosz Duszel

UNLV Theses, Dissertations, Professional Papers, and Capstones

Topic of this master's thesis is connected with task allocation algorithms and mesh networks. Author of this work has already graduated from Wroclaw, University of Technology (Poland) where during his studies he created software simulation environment for two different task allocation algorithms for mesh networks:Adaptive ScanandFrame Sliding. Those algorithms were compared by two, main parame- ters: simulation time and average mesh fulfillment (utilization level). All simulations were done in software environment which was developed specially for that research. This application was based on few, different types of objects: task (width, height, processing time), task queue (different number of tasks), task …

Design And Fabrication Of An Infrared Optical Pyrometer Asic As A Diagnostic For Shock Physics Experiments, Jared Gordon

UNLV Theses, Dissertations, Professional Papers, and Capstones

Optical pyrometry is the sensing of thermal radiation emitted from an object using a photoconductive device to convert photons into electrons, and is an important diagnostic tool in shock physics experiments. Data obtained from an optical pyrometer can be used to generate a blackbody curve of the material prior to and after being shocked by a high speed projectile. The sensing element consists of an InGaAs photodiode array, biasing circuitry, and multiple transimpedance amplifiers to boost the weak photocurrent from the noisy dark current into a signal that can eventually be digitized. Once the circuit elements have been defined, more …

Adaptive Transmission For Ofdm, Michael Juang

All Theses

To respond to dynamic channel conditions caused by fading, shadowing, and other time-varying disturbances, orthogonal frequency division multiplexing (OFDM) packet radio systems should adapt transmission parameters on a packet-by-packet basis to maintain or improve performance over the channel. For this to be possible, there are three key ideas that must be addressed: first, how to determine the subchannel conditions; second, which transmission parameters should be adapted; and third, how to adapt those parameters intelligently. In this thesis, we propose a procedure for determining relative subchannel quality without using any traditional channel measurements. Instead, statistics derived solely from subcarrier error counts …

Bite Detection And Differentiation Using Templates Of Wrist Motion, Soheila Eskandari

All Theses

We introduce a new algorithm of bite detection during an eating activity based on template matching. The algorithm uses a template to model the motion of the wrist over a 6-second window centered on the time when a person takes a bite. We also determine if different types of bites (for example food vs. drink, or using different types of utensils) have different wrist motion templates. This method is implemented on 22,383 bites and 5 different types of templates are built. We then describe a method to recognize different types of bites using the set of templates. The obtained accuracy …

Study On Electromagnetic Scattering Of Cylinders Buried In A Half Space With Random Rough Surfaces Of Finite/Infinite Length, Yueyang Dai

All Dissertations

Analysis of electromagnetic scattering of buried objects is a subject of great interest due to its practical importance in both military and civil applications, such as subsurface investigation and target detection. In reality, the earth is of layered structure of random rough interfaces, which leads to a greatly increased complexity of the analysis. However, it is necessary to incorporate the nature of random rough surface and the layered structure because they both have substantial impact on the scattered signature and hence affect the study of inverse scattering and detection of buried objects. In this dissertation, a Monte-Carlo multidomain pseudospectral time …

A Hybrid Method Of Performing Electric Power System Fault Ride-Through Evaluations On Medium Voltage Multi-Megawatt Devices, John Fox

All Dissertations

This dissertation explores the design and analysis of a Hybrid Method of performing electrical power system fault ride-through evaluations on multi-megawatt, medium voltage power conversion equipment. Fault ride-through evaluations on such equipment are needed in order to verify and validate full scale designs prior to being implemented in the field. Ultimately, these evaluations will help in reducing the deployment risks associated with bringing new technologies into the marketplace. This is especially true for renewable energy and utility scale energy storage systems, where a significant amount of attention in recent years has focused on their ever increasing role in power system …

Encapsulated And Monolithic Resonant Structures For Laser Applications, Aaron Pung

All Dissertations

Typically, the composition of a laser system includes a gain medium, a pump illumination source, and an external feedback cavity. This cavity consists of a highly reflective mirror and an outcoupler component. The geometry of the outcoupler can be engineered to tailor the reflected or transmitted beam's spatial and spectral distribution. Functionally, the transmitted beam profile is dependent on the laser application. Broadband reflection profiles can be obtained by utilizing a distributed Bragg reflector (DBR). A DBR device consists of multiple layers of alternating materials. Constructive interference of the reflected light off each interface between different materials produces the spectrally …

Adaptive Transmission Protocols For Wireless Communication Systems With Fountain Coding, Jason Ellis

All Dissertations

We present low-complexity adaptive protocols for both unicast and multicast transmission in wireless communication systems that employ higher layer fountain codes. Our adaptive protocols respond to variations in channel conditions by adapting the modulation and channel coding of transmitted packets, and they provide efficient communication over wireless channels that experience fading, shadowing, and other time-varying propagation losses. The operation of our protocols is governed by simple receiver statistics that can be obtained during the demodulation of received packets. We present three adaptive protocols for fountain-coded unicast transmission, and compare the throughput performance of our protocols with that of fixed-rate systems, …

Distortion-Tolerant Communications With Correlated Information, Ning Sun

Graduate Theses and Dissertations

This dissertation is devoted to the development of distortion-tolerant communication techniques by exploiting the spatial and/or temporal correlation in a broad range of wireless communication systems under various system configurations. Signals observed in wireless communication systems are often correlated in the spatial and/or temporal domains, and the correlation can be used to facilitate system designs and to improve system performance. First, the optimum

node density, i.e., the optimum number of nodes in a unit area, is identified by utilizing the spatial data correlation in the one- and two-dimensional wireless sensor networks (WSNs), under the

constraint of fixed power per unit …

A Reconfigurable Digital-To-Analog Converter With Supply Invariant Linearity, Nicholas J. Chiolino

Graduate Theses and Dissertations

A novel reconfigurable digital-to-analog converter (DAC) with supply independent linearity is presented. The process agnostic converter achieves wide supply range operation and re-configurability by being charge based. This converter consists of a 7-bit parallel digital input control core and an analog "summing" core utilizing charging capacitors with an operational transconductance amplifier in a voltage-follower configuration. This topology is highly configurable to allow for optimization across process voltages, step sizes and low power operation. The specification of the DAC is (1) supply independence (2) low power operation (3) operation up to 200 kHz and (4) conversion control through a DAC enable …

A Wide Bandgap Silicon Carbide (Sic) Gate Driver For High Temperature, High Voltage, And High Frequency Applications, Ranjan Raj Lamichhane

Graduate Theses and Dissertations

The potential of silicon carbide (SiC) for modern power electronics applications is revolutionary because of its superior material properties including substantially better breakdown voltage, power density, device leakage, thermal conductivity, and switching speed. Integration of gate driver circuitry on the same chip, or in the same package, as the power device would significantly reduce the parasitic inductance, require far less thermal management paraphernalia, reduce cost and size of the system, and result in more efficient and reliable electrical and thermal performance of the system.

The design of a gate driver circuit with good performance parameters in this completely new under-development …

Proteins In High Electric Fields, David Michael Landry

Theses and Dissertations

Being able to control protein function directly and in real time is attractive. In this thesis, I discuss controlling protein activity using alternating current electric fields on the order of 1 MV/m. Since protein structures result in localized and/or protein-wide charge gradients, it is expected that a sufficiently high electric field applied across a protein should result in structural distortions which can temporarily alter or halt protein function. The field is set to oscillate above the influences of the electrochemical double layer effects (1 kHz) and below the level needed for hydrodynamic rotation of proteins (10 MHz). A device is …

An Algorithm To Recognize Multi-Stable Behavior From An Ensemble Of Stochastic Simulation Runs, Eduardo Monzon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Synthetic biological designers are demanding tools to help with the design and verification process of new biological models. Some of the most common tools available aggregate multiple simulation results into one “clean” trajectory that hopefully is representative of the system’s behavior. However, for systems exhibiting multiple stable states, these techniques fail to show all the possible trajectories of the system. This work introduces a method capable of detecting the presence of more than one “typical” trajectory in a system, which can also be integrated with other available simulation tools.

Synchronous Data Link Control Communication Chip, C. Alva Barney, Dr. Doran K. Wilde

Journal of Undergraduate Research

In conjunction with the ORCA research grant I was able to design, layout and simulate an integrated Synchronous Data Link Control (SDLC) communication chip. SDLC communication chips are commonly used to transfer data between computers in serial bit-wise transmission. Extensions of the SDLC are used in high speed data links and satellite communication. In addition, this project was accompanied with full web documentation such that the VLSI Design Class (ECEn 451) can leverage my research and design as a class project.

Challenges And Opportunities For Multi-Functional Oxide Thin Films For Voltage Tunable Radio Frequency/Microwave Components, Guru Subramanyam, Melanie W. Cole, Nian X. Sun, Thottam S. Kalkur, Nick M. Sbrockey, Gary S. Tompa, Xiaomei Guo, Chonglin Chen, S. P. Alpay, G. A. Rossetti, Kaushik Dayal, Long-Qing Chen, Darrell Schlom

Electrical and Computer Engineering Faculty Publications

There has been significant progress on the fundamental science and technological applications of complex oxides and multiferroics. Among complex oxide thin films, barium strontium titanate (BST) has become the material of choice for room-temperature-based voltage-tunable dielectric thin films, due to its large dielectric tunability and low microwave loss at room temperature. BST thin film varactor technology based reconfigurable radio frequency (RF)/microwave components have been demonstrated with the potential to lower the size, weight, and power needs of a future generation of communication and radar systems. Low-power multiferroic devices have also been recently demonstrated. Strong magneto-electric coupling has also been demonstrated …

Vehicular Motion Sensor: Developing A Wide-Range Motion Sensing Alarm System, Joshua Isaacson

Senior Honors Theses

Vehicular safety has become a serious concern in recent years. Many drivers have difficulty backing out of parking spaces, especially when large trucks and sport utility vehicles block the peripheral view from smaller vehicles. This can lead to accidents and pedestrian injuries when drivers are unable to see or do not pay careful attention to their surroundings.

Vehicular motion sensor systems can alert drivers of approaching obstacles when attempting to back out of parking spaces with limited visibility. This thesis aims to explain the limitations of current systems and the research conducted by the author to develop a prototype for …

Role Of Atomic Variability In Dielectric Charging: A First-Principles-Based Multiscale Modeling Study, Ravi Pramod Kumar Vedula, Sambit Palit, Muhammad A. Alam, Alejandro Strachan

Birck and NCN Publications

We present a dielectric charging model that combinesab initiocalculations of trap levels with a continuum-level transport model and apply it to interpret charging currents in amorphous silicon nitride. Density functional theory calculations on an ensemble of structures predict a distribution of electron trap levels up to 1.8 eV below the conduction band edge and provide insight into the physical trapping mechanisms. Incorporating this information in the continuum model, as opposed to the standard approach of a single adjustable trap level, not only leads to a more accurate description of experimental current transients in metal-insulator-metal capacitors, but also to a more …

Enhancing Ground Based Telescope Performance With Image Processing, John C. Zingarelli

Theses and Dissertations

The Space Surveillance Telescope (SST) is a Defense Advanced Research Projects Agency (DARPA) program designed to detect objects in space like Near Earth Asteroids (NEAs) and space debris in the Geosynchronous Earth Orbit (GEO) belt. Binary hypothesis tests (BHTs) have historically been used to facilitate the detection of new objects in space. In this dissertation, a multi-hypothesis test (MHT) detection strategy is introduced to improve the detection performance of the SST. In this context, the MHT determines if an unresolvable point source is in the center, corner or side of a pixel in contrast to a BHT, which only tests …

An Incremental Trace-Based Debug System For Field-Programmable Gate-Arrays, Jared Matthew Keeley

Theses and Dissertations

Modern society increasingly relies upon integrated circuits (ICs). It can be very costly if ICs do not function properly, and large portions of designer effort are spent on their verification. The use of field-programmable gate arrays (FPGAs) for verification and debug of ICs is increasing. FPGAs are faster than simulation and cost less than fabricating an ASIC prototype. However, the major challenge of using FPGAs for verification and debug is observability. Designers must use special techniques to observe the values of FPGA's internal signals. This thesis proposes a new method for increasing the observability of FPGAs and demonstrates its feasibility. …

Tonescale Compression For Electroluminescent Display, Michael E. Miller, Christopher J. White

AFIT Patents

A method for controlling an electroluminescent display to produce an image for display that has reduced luminance to reduce burn-in on the display while maintaining visible contrast, includes providing the electroluminescent (EL) display having a plurality of EL emitters, the luminance of the light produced by each EL emitter being responsive to a respective drive signal; receiving a respective input image signal for each EL emitter; and transforming the input image signals to a plurality of drive signals that have a reduced peak frame luminance value but maintains contrast in the displayed image to reduce burn-in by adjusting the drive …