Electrical and Computer Engineering Commons^™

Slow Complexity Wavelet Packet Compression Of Bayer Images For Communication Over Wireless Sensor Networks, Ivan Calzada

Open Access Theses & Dissertations

The purpose of this thesis was to develop a low complexity image compression algorithm for Wireless Sensor Networks (WSN). The main constraints in a WSN node are limited processing power, memory allocation, and battery life. The goal of this thesis was to develop an image compression algorithm that would thrive under this constraint environment. The main focus was to minimize the complexity of the algorithm by taking advantage of the spatial correlation found in Bayer images. The algorithm employs line based 1-D Discrete Wavelet Packets Transform of Bayer images. In addition the image compression method includes the application of a …

Simulation And Optimization Of Ultra Thin Photovoltaics, Jose Luis Cruz-Campa

Open Access Theses & Dissertations

Sandia National Laboratories (SNL) conducts pioneering research and development in Micro-Electro-Mechanical Systems (MEMS) and solar cell research. This dissertation project combines these two areas to create ultra-thin small-form-factor crystalline silicon (c-Si) solar cells. These miniature solar cells create a new class of photovoltaics with potentially novel applications and benefits such as dramatic reductions in cost, weight and material usage.

At the beginning of the project, unusually low efficiencies were obtained in the research group. The intention of this research was thus to investigate the main causes of the low efficiencies through simulation, design, fabrication, and characterization.

Commercial simulation tools were …

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

Open Access Theses & Dissertations

Not Required

Generation Of High Resolution Radar Signals Using Three Dimensional Chaotic Flows, Chandra Sekhar Pappu

Open Access Theses & Dissertations

The purpose of this project is to investigate the system parameter and certain signal processing techniques to achieve wide bandwidth and frequency agility in order to build a high resolution radar. The technique relies on the output of an n-dimensional (n>2) non-linear system that exhibits chaotic behavior.

Firstly, the compressed Lorenz attractor is considered which has a set of three state variables x, y and z and three control parameters &rho, &beta, and &sigma. By varying &rho and &beta as function of time highly chaotic parameter space region is simulated such that chaotic signal behaves optimally.

For comparison purpose …

12 Bit Charge Redistribution Digital To Analog Converter For The Residence Time Fluxgate Magnetometer, Miguel Angel Alamillo

Open Access Theses & Dissertations

The continuous advances in CMOS VLSI technology have culminated in high speed, low voltage CMOS digital circuits with gate delays below 50 ps at 1.5 V supply. At the same time, high voltage analog signal processing has fallen behind to the high flexibility and high reliability of DSP. However, the main drawback of DSP is the need for high accuracy low distortion data converters and as a consequence of the persistent efforts of reducing size, cost and power of solid-state components the field of CMOS Mixed-Signal circuit design has become of the utmost importance.

The obvious functionality of data converters …

Multidisciplinary Collaborative Model For Complex, Angel Ernesto Delgado

Open Access Theses & Dissertations

Nowadays, most devices with advanced technology require the development of embedded systems with mechanical and electrical components as well as software including more than one discipline. These are devices that are usually complex in terms of composition and functionality and that design must follow a methodology in order to successfully design and launch a device of this nature. Hence, the assembly of a multidisciplinary engineering group is required to carry out such complex devices and develop a fully functional product. The group may also need an expert on the field that can provide guidance and knowledge where needed. This is …

Development Of A Quality Of Service Framework For Multimedia Streaming Applications, Stuart Wallace

Masters

By the year 2012, it is expected that the majority of all Internet traffic will be video content. Coupled with this is the increasing availability of Wireless Local Area Networks (WLANs) due to their ease of deployment, flexibility and reducing roll out costs. Unfortunately the contention based access mechanism utilised by IEEE 802.11 WLANs does not suit the non-uniform or bursty bandwidth profile of a video stream which can lead to a reduced quality of service (QoS) being experienced by the end-user. In 2005, the IEEE 802.11e protocol was ratified in an attempt to solve this emerging problem. It provides …

Blind Single Channel Sound Source Separation, Mark Leddy

Masters

In recent years source separation has become an increasingly popular area of research in the signal processing community. The subject has found applications in a variety of fields such as medical imaging, sound and audio, econometrics and geophysics. This document will discuss the application of source separation techniques to the area of audio. Sound source separation is the process of observing a mixture signal made up of a number of sources, and from this mixture estimating the individual source signals. Audio source separation techniques may be crudely split into the following areas; techniques that utilise attributes of the sources, and …

Technological Challenges Of 1-Dimensional Magnetic Photonic Crystals, Mikhail Vasiliev, Kamal Alameh, Dmitry E. Balabanov, Vladimir I. Burkov, V. V. Koledov, Viacheslav A. Kotov, V. G. Shavrov, Anotoly K. Zvezdin

Research outputs pre 2011

Visible-region magnetic photonic crystals (MPC) designed for higher-order bandgap operation have been proposed to overcome the technological restrictions originating from the strong thickness dependency of the individual magnetic layer properties observed in MPC structures.

On The Effect Of Hydrodynamic Slip On The Polarization Of A Nonconducting Spherical Particle In An Alternating Electric Field, Hui Zhao

Mechanical Engineering Faculty Publications

The polarization of a charged, dielectric, spherical particle with a hydrodynamically slipping surface under the influence of a uniform alternating electric field is studied by solving the standard model (the Poisson–Nernst–Planck equations). The dipole moment characterizing the strength of the polarization is computed as a function of the double layer thickness, the electric field frequency, the particle’s surface charge, and the slip length. Our studies reveal that two processes contribute to the dipole moment: ion transport inside the double layer driven by the electric field and the particle’s electrophoretic motion. The hydrodynamic slip will simultaneously impact both processes. In the …

Computational Complexity Of Signal Processing Functions In Software Radio, Kushal Y. Shah

ETD Archive

The increased usage of mobile communication devices has imposed a challenge of achieving efficient communication with minimum power consumption. Moreover, with the advent of software defined radios (SDR), it is highly possible that signal processing functions would be implemented in software in future mobile devices. Hence, the power consumption of these future devices will be directly related to the power consumed by the processor that executes SDR software. This thesis aims at analyzing the computational complexity of different modulation schemes and signal processing communication functions of IEEE WiFi standard. This analysis provides good insight on how the computational load varies …

Reverse Engineering Aspects To Derive Application Class Models, Irenee Morcos George Magdalla

ETD Archive

Aspects provide a nice way to modify behavior and implement cross-cutting concerns in object-oriented systems. As such, aspects do not have an existence of their own the application classes that the aspects refer to must be present in order to instantiate the aspects. In this research, we present a reverse engineering approach to generate a minimal class model that has all the structural elements necessary in order to complete exercise a set of aspects

Dc-Dc Power Converter Design For Application In Welding Power Source For The Retail Market, Edward J. Oshaben

ETD Archive

The purpose of this study is to design and analyze a DC-DC power converter for application in a welding power source that is cost-competitive with the more traditional, lower-tech welding power source topologies. This thesis first presents a background study of recent design approaches to DC-DC power converters, as they relate to application in welding power converters. The background study also surveys recent design approaches to welding power source controls. Evaluation of available options in DC-DC converter topologies and switching schemes for application in a welding power source is presented. Design methodology of a low-cost DC-DC converter for application in …

Experimental Study Of Cooperative Communication Using Software Defined Radios, Murali Krishna Marunganti

ETD Archive

The aim of this thesis is to implement and test a real time wireless communication environment. Cooperative Communication is one of the methods by which a reliable communication can be obtained. This is performed using a Software Defined Radio. The received output is compared with the actual signal that is transmitted over the wireless channel. The wireless communications are often hindered by the noisy environments and make the system unreliable. The interference from neighboring nodes also poses a major disadvantage. There is a necessity to improve the performance of the system where the neighbor nodes can work in coordination with …

Automatic Utility Meter Reading, Kaicheng Xie

ETD Archive

This thesis discusses research in the automation of reading a utility meter. The hardware required is a wireless camera pointed at the meter to be read. This meter can be a water, electricity or gas meter. After the wireless camera collects the image from the utility meter it transmits the image to a computer through a receiver. The computer analyzes the image with pattern recognition technology to obtain the numbers. We use image processing techniques in this thesis, including image preprocessing, image segmentation (Otsu threshold method), and number recognition. Finally we create a graphical user interface using Visual C#®

Evaluation And Comparison Of Mac Protocols In Wireless Sensor Networks, Sharmila Kollipara

ETD Archive

Wireless sensor network applications call for different kinds of network protocols at different levels of the network stack based on application requirements. A number of medium access control (MAC) protocols have been proposed in the literature. Evaluation of most of these MAC protocols have typically been based on simulation, and while such simulation provides interesting insight into the behavior of these protocols, artifacts caused by behavior of hardware is ignored. Further more, MAC protocols are usually evaluated by comparing the new protocol with others based on one or two metrics, the ones that determined the design decisions for the protocol …

A Generalized Inverter Control Method For A Variable Speed Wind Power System Under Unbalanced Operating Conditions, Shuang Wu

ETD Archive

This thesis presents a generalized control method for complete harmonic elimination and adjustable power factor of a grid side inverter under unbalanced operating conditions used in variable speed wind power systems. The theoretical analysis of the proposed control method is described and verified by simulation in Simulink®. Two types of traditional control methods are also explained and applied in the wind power system for comparison, which are the indirect current control in a-b-c reference frame and the active and reactive power control in d-q synchronous frame. This method is verified for the gird fault right-through operation as well

Implementation And Evaluation Of A Tdma Based Protocol For Wireless Sensor Networks, Robert M. Fiske

ETD Archive

When evaluating MAC layer network protocols for wireless sensor networks performing simulations of a protocol's operation can provide great insight into the performance of the protocol. In order to prove that a protocol will work in a real setting and not just at the theoretical level, however, there is no substitute for evaluation with a physical implementation. This thesis discusses a physical implementation and evaluation of the Many-to-One-Sensor-to-Sink (MOSS) MAC layer protocol for sink based wireless sensor networks using the MAC Layer Architecture for TinyOS. MOSS is a Time Division Multiple Access (TDMA) based protocol first proposed in an earlier …

Dynamics And Control Of An Electric Power Assist Steering System, Prasanth Babu Kandula

ETD Archive

In this thesis an Active Disturbance Rejection Controller (ADRC) is applied to Electrical Power Assist Steering (EPAS) system which assists the driver in steering the steering wheel of an automobile. Our control objective is to reduce the steering torque exerted by a driver, so that good steering feel of the driver will be achieved in the presence of external disturbances and system uncertainties which are very common in the EPAS system. The robustness and stability of ADRC controlled EPAS system is investigated through frequency-domain analyses. The Bode diagrams and stability margins demonstrate that the control system is stable during the …

Sensing And Control Of Mems Accelerometers Using Kalman Filter, Kai Zhang

ETD Archive

Surface micromachined low-capacitance MEMS capacitive accelerometers which integrated CMOS readout circuit generally have a noise above 0.02g. Force-to-rebalance feedback control that is commonly used in MEMS accelerometers can improve the performances of accelerometers such as increasing their stability, bandwidth and dynamic range. However, the controller also increases the noise floor. There are two major sources of the noise in MEMS accelerometer. They are electronic noise from the CMOS readout circuit and thermal-mechanical Brownian noise caused by damping. Kalman filter is an effective solution to the problem of reducing the effects of the noises through estimating and canceling the states contaminated …