Engineering Commons^™

Pulsed Compression For Aerosol Ranging With Coherent Pulse-Doppler Lidar Systems, Jerry L. Rogers

Theses and Dissertations

This thesis provides a thorough review of conventional matched filter radar theory as it applies to aerosol sensing lidar. Basic matched-filter radar theory and the complex, dense aerosol target model eventually lead to a general derivation of the matched-filter radar receiver response to a dense aerosol target environment. The matched-filter response is obtained in terms of a two dimensional convolution of the target scattering function and the radar ambiguity function. The range and radial velocity resolution of various radar signals were compared using the matched-filter radar receiver and scattering function models. Pulse compression radar signals were compared to the simple …

Te Scattering From A Dielectric Coated Conducting Strip, William D. Wood Jr.

Theses and Dissertations

Consider a plane wave incident on a conducting strip of infinite length coated on one side with a thin, uniform coating of lossless dielectric, and let the incident magnetic field vector be parallel to the edges of the strip. From first principles we develop the integral equations relating the total, incident, and scattered fields in the dielectric. We expand the fields in the dielectric slab as the sum of three plane waves (the 'forced' wave and two oppositely-directed surface waves). The phase constants in the x and y directions are known and the wave amplitudes are found using least-squared- error-point-matching. …

Automatic Flight Control System Design For An Unmanned Research Vehicle Using Discrete Quantitative Feedback Theory, David G. Wheaton

Theses and Dissertations

This thesis presents the application of non-minimum phase (NMP) w'- plane discrete MIMO (multiple-input-multiple-output) Quantitative Feedback Theory (QFT) to the design of a three-axis rate-commanded automatic flight control system for an unmanned research vehicle (URV). The URV model used has seven inputs and three outputs derived from the small-angle perturbation equations of motion. Plant parameter uncertainty consists of six flight conditions derived from variations in the aircraft center of gravity, airspeed, and gross weight. A weighting matrix delts is used to post-multiply the plants for blending the seven effector inputs into three effective rate-command inputs and resulting in an effective …

An Evaluation Of An Ada Implementation Of The Rete Algorithm For Embedded Flight Processors, F. Jesse Fanning

Theses and Dissertations

The purpose of this thesis was to design and develop an expert system shell in Ada, and to evaluate the shell's execution and size performance to determine its suitability for real-time operation on the MIL-STD-1750A embedded flight processor. The expert system shell uses the CLIPS/Ada inference engine, a forward-chaining Ada implementation of Rete. The expert system shell design is presented along with an overview of the target environment--the MIL-STD-1750A VHSIC Avionic Modular Processor (VAMP) running under the Ada Avionics Real-Time Software (AARTS) Operating System. Theoretical and empirical complexity analyses of the inference engine are presented and discussed in view of …

Oscillation Frequency In High-Gain Lasers, Lee W. Casperson

Electrical and Computer Engineering Faculty Publications and Presentations

The calculation of the oscillation frequency of a single-mode laser oscillator is examined systematically. Mode-pulling formulas are developed for a variety of laser systems, and the limitations of a standard approximation are explored.

Estimation Of Evoked Fields Using A Time-Sequenced Adaptive Filter With The Modified P-Vector Algorithm, Jeffery A. Kepley

Theses and Dissertations

This thesis describes a time sequenced adaptive filter developed to estimate visually evoked fields (EF) using visually evoked potentials (EP). These non-stationary signals are buried in strong background noise. The two types of noise are magnetoencephalogram (MEG) and electronencephalogram (EEG). The filter implementation is based on the Ferrara Time Sequenced Adaptive (TSAF) using the Least-Mean-Square (LMS) algorithm and the Williams modified P-vector algorithm (mPa). This essentially results in two filters. A two stage filter structure is used in which the first stage removes the time-varying mean of the input signals. This allows the second stage to process zero-mean signals which …

Characterization Of Sige/Si Heterostructures Formed By Ge+ And C+ Implantation, Akira Fukami, Ken-Ichi Shoji, Takahiro Nagano, Cary Y. Yang

Electrical and Computer Engineering

Formation of SiGe/Si heterostructures by germanium ion implantation was investigated. A germanium‐implanted layer was grown epitaxially in the solid phase by thermal annealing. Two kinds of crystalline defects were observed. One is a misfit dislocation, and the other is a residual dislocation caused by ion bombardment. The p‐n junction formed in the SiGe layer has a leakage current three orders of magnitude larger than that of a pure Si p‐n junction fabricated with an identical process except for the Ge+ implantation. Carbon doping in the SiGe layer improves its crystalline quality and the junction characteristics.

A 512 X 512 Random Addressable Variable Resolution Image Sensor, Chakravarthy Yarlagadda

Theses

This thesis presents the design and layout of a 512 x 512-element with 20μm x 20μm pixels image sensor that emulates the properties of the human eye and is useful in high speed processing of visual data for machine vision applications. The imager will be able to operate with random-address selection in variable resolution or with multiple regions of interest to reduce the number of pixels readout. The selection of the pixels is done by x-y addressing the MOS switches which connect the photodiode pixel to the output through the sense lines. The design of column decoder and row decoder …

Photo-Induced Electrochemical Etching Of Inp Semiconductor In A Thin Film Cell, Bungsu Iskandar

Theses

The Photo-Induced Electrochemical Etching of n-InP wafer in aqueous solution is investigated for both reservoir and capillary systems. A sinusoidal spatial variation of light intensity pattern is directly illuminated and promoting etching on an InP semiconductor wafer. The etching process is time-efficient, and produces highly isotropical and a promising high resolution pattern. It gives a good reproducibility and has less contaminating features. Its features may be explained by a non-linear relationship between the electrolyte concentration and the photo-generated holes density at the interaction surface. An optimal reaction rate is determined by the ratio of the reactivity to ionic diffusion, either …

Rotary Micromotor Design With Ic-Compatible Processing, Hong Yu

Theses

Several microelectromechanical rotary motors have been designed and simulated with varying rotor and stator configurations. All of these micromotors operate with an electrostatic power source and have rotor diameters varying from 0.2 to 0.4 mm. These micromotors develop torques in the range 8 to 50 picoNewtons with rotors of polysilicon with 2 micron film thickness based on the detailed simulations of this thesis using a 3-phase voltage power source. The geometries modelled in this work are side-drive and vertical-drive configurations. These micromotors obtain drive torque from the fringe-field differential at the periphery of the rotor poles.

Unlevitated micromotors (with bearings) …

Deep Level Characterization Studies In Gaas, Gordhan R. Barevadia

Electrical & Computer Engineering Theses & Dissertations

The goal of this research was to investigate deep levels in different types of GaAs, a material for high power optically controlled bulk semiconductor switches. For low resistivity semiconductors, such as silicon doped GaAs material (p =0.054 Ω cm), deep level transient spectroscopy (DLTS) was used to characterize deep levels. Three deep levels (EL6, EL3, and EL2) have been detected in this material. For high resistivity semiconductors (p > 10⁴ Ω cm), difficulty of electrical carrier injection and of making a junction does not permit the use of DLTS technique. Therefore, an experimental set-up of the photo-induced current transient spectroscopy …

Optical And High Electric Field Effects In Bulk Gallium Arsenide Switches, Randy Roush

Electrical & Computer Engineering Theses & Dissertations

During the past few years, bulk, photoconductive switching has become recognized as a viable topic for future research on moderate and high power switches. The two-pulse, or BOSS, concept relies on an excitation laser pulse, and a separate de-excitation pulse in conjunction with silicon doped, copper compensated, GaAs to create a variable temporal electrical pulse width. The research contained in this document provides information concerning the feasibility of the BOSS concept, as the switch is scaled to larger sizes, and higher voltage and current. The major concern will be the high voltage and current effects. The absorption length for 1064 …

Measurement Of Thermal Noise In Condenser Microphones In A Vacuum-Isolation Vessel, Kim Chi Thi Ngo

Electrical & Computer Engineering Theses & Dissertations

The electrical noise generated by thermal agitation of the air molecules impinging upon the membrane of a condenser microphone and from its associated preamplifier has been studied analytically and experimentally over a wide bandwidth. These background noise levels constitute one of the most important specifications of a microphone for they determine the lowest sound pressure that can be detected. Therefore, a new method for measuring the thermal agitation noise within a bandwidth of 1-25600 Hz has been developed. The theoretical and experimental measurements of thermal agitation noise in a condenser microphone by enclosing the microphone in a vessel which is …

Integrated Control Of Thermally Distorted Large Space Antennas, Robert H. Tolson

Mechanical & Aerospace Engineering Theses & Dissertations

Studies on controlling the thermal distortion of large space antennae have generally investigated a single orbital position and have optimized actuator locations based on minimizing the RMS surface deviation from the original parabolic shape. One study showed the benefits of directly using far zone electric field characteristics as the performance measure; but, this approach resulted in a nonlinear programming problem. The objective of the current study is to develop an approach to designing a control system that (1) recognizes the time dependence of the distortion and (2) controls variables that are directly related to far field performance in a quadratic …

The Modeling Of The Interactions Of Pellets With Magnetic Fusion Plasmas For Alpha Particle Diagnostics, Abdel-Ghafar Mahmood El-Cashlan

Electrical & Computer Engineering Theses & Dissertations

A model for the interactions of hydrogen and carbon pellets with thermonuclear fusion plasmas has been developed and solved to determine the charge-state spatial distributions in the ablation cloud surrounding the pellet. The ionization is treated in a self-consistent manner in the energy balance and the collisional radiative (CR) model is used to calculate the ionization levels. External plasma electron effects on ionization are included. The electron heat flux is modeled as a multigroup distribution. The channelling of the flow along the field line is treated phenomenologically by restricting the cross-sectional area of the flow. The predictions of the model …

Design Of A Cmos Temperature Sensor With Eeprom Error Correction Scheme, Jin-Ku Kang

Theses

This thesis describes the design and operation of a CMOS temperature sensor operating at very low power with an EEPROM error correction scheme including the physical layout. This device is designed for applications requiring very low power including biomedical and optically powered device applications. The sensor output is an analog voltage. The temperature sensing cell is implemented with two BJTs having different emitter areas. An op amp dissipating about 300 micro-watts power is designed and is used to amplify the sensor output voltage with a gain of 85dB. A novel EEPROM is used to correct nonlinearity error of the temperature …

A Transputer Based Distributed Graphics Display, Ramana V. Kattula

Theses

The design of a transputer based graphics display is discussed. The problems associated with the single processor graphics systems are described. A solution based on multiple transputers is proposed. The transputer based graphics display described is a general purpose graphics system which can achieve any required compute performance and drawing performance without using special hardware. The display resolution and color depth can be enhanced as per the user requirements with little or no change in hardware.

Simulation And Analysis Of Priority Classes In Extended Token Based Local Area Networks, Bhavinkumar R. Pathak

Theses

Recently, Local Area Networks carrying multiple priority classes of messages have received considerable attention. The IEEE 802.5 token ring standard defines an optional priority scheme to handle different priority classes of messages. A simulation model of symmetric priority based networks, consisting of token ring networks interconnected by a bridge is considered. Messages are divided into two priority classes, namely, high priority traffic and low priority traffic. High priority traffic is guaranteed access on the channel, whereas low priority messages are served when the system determines that no high priority messages are currently waiting. The simulation results are used to evaluate …

A Self Testing Strategy For The Wafer Scale Hierarchical Memory Architecture, Maremanda V. R. Rao

Theses

Since the early 1960's, semiconductor chips have matured from single transistor devices to one million transistors per chip. The integration has been achieved by reducing transistor dimensions, and by increasing chip sizes. However, physical limits are being reached as submicrometre dimensions are approached. Fault tolerance has to be used to maintain the increase in the chip complexity. Yield improvement is only one of the many possible gains of fault tolerance. The dense integration of logic on a single chip also creates a huge test problem. in recent years a great deal of effort has gone into the development of yield …

Microengineered Thermal Conductivity Vacuum Pressure Sensor, Sanjay Talreja

Theses

This thesis details the first designs for microengineered vacuum pressure gauges based on silicon microelectronic technology. A monolithic polysilicon air-bridge structure (supported at both ends), within a Wheatstone bridge circuit, is used as a pressure sensor. The device utilizes the change of the thermal conductivity of a gas with ambient gas pressure. The doubly supported beam functions as a temperature sensitive resistor with a negative temperature coefficient of resistivity. Thermal change of resistance monitored as a measure of ambient pressure constitutes the basis of operation for this sensor. The sensor operates over the pressure ranging from 1 Torr to 10 …

Simulation And Analysis Of Integrated Lans For Hospital Environment, Naveen K. Verma

Theses

Hospitals generate a large number of data sets of different types and formats and it is required to integrate these data sets for their rapid and simultaneous communication in order for a better treatment of patients and to cut the escalating costs. A better approach to meet this requirement is to have a distributed system linked all together with a high capacity LAN using an efficient integration method.

This thesis begins by studying the characteristic feature and suitability of Queued Packet & Synchronous Exchange (QPSX) network architecture. The network models are simulated for QPSX, Ethernet and Token Bus networks for …

Microengineered Silicon Beam Switch For Fiber Optics, Hsu-Nien Yang

Theses

A novel microelectromechanical actuator has been designed for moving an optical input fiber into alignment with one of three stationary output fibers. This switching device thus can connect an input optical port to one of 3 selected optical ports. The actuation force is created by a vertical-drive armature measuring 0.5x2.7 mm² mechanically tethered to the input optical fiber. A force of 2.33 mN is obtained from the linear acturator when the vertical stator armature gap is one micron and the applied three phase voltage is 140 Volts. The required force is a function of the input fiber length, e.g. …

Max/Min : A Novel Rank Order Based Filter Family, Raafat E. Kamel

Theses

In the early development of signal and image processing, linear filters were the primary tools. Their mathematical simplicity made them easy to design and implement. They also offered satisfactory performance in many applications. However, they show poor performance in other cases, such as image processing.

Nonlinear filtering offered a solution to these problems. Nonlinear filtering has undergone a lot development for a long time. Among the first known nonlinear filters was the median filter, which was proposed by Tukey. Median filter preserves signal or image details better compared to a linear filter. Later other nonlinear filters were developed, including median …

Implementation Of Parallel Sorting Algorithms On A Transputer Network, Venkatraman U. Calidas

Theses

Many sorting algorithms, such as the bubble sort and the binary tree selection sort, are n-squared algorithms and take O (n2) time to sort n values. These can be easily parallelized; the resulting sorts are called the odd-even transposition sort and the parallel tree selection sort, respectively. These have O(nlogn) time complexity. The quicksort is an O(nlogn) algorithm and it can parallelized to make it an O(logn) algorithm.

A transputer is a microprocessor which has serial links to transmit and receive data from other transputers. The above algorithms are implemented on a network of transputers and the link connections for …

An Optically Powered Cmos On-Chip Power Supply, Jaeyong Jeong

Theses

This thesis presents an optically powered CMOS on-chip power supply for CMOS IC applications. There exists a need for specialized chips that are located remotely and are powered by light supplied through fiber-optic cabling. An optically powered CMOS on-chip power supply circuit described in this thesis is composed of three subcircuits; light to voltage converter circuit, clock pulse generator circuit, and voltage multiplier circuit. Each subcircuit has been analyzed and designed, and simmulated using SPICE 2G.5/6 with 3pm CMOS SPICE parameters from the MOSIS. The circuits layout has been done using MAGIC according to the MOSIS scalable CMOS design rules. …

Landmark-Based Partial Shape Recognition By A Two-Stage Bam Neural Network, Xianjun Liu

Theses

In this thesis, we develop a Bitfirectional Associative Memory (BAM) based neural network to achieve partial shape recognition. To recognize objects which are partially occluded, we represent each object by a set of landmarks. The landmarks of an object are points of interest relative to the object that have important shape attributes. To achieve recognition, feature values (landmark values) of each model object are trained and stored in the network. Each memory cell is trained to store landmark values of a model object for all possible positions. Given a scene which may consist of several objects, landmarks in the scene …

Investigation Of Micromechanical Properties Of Tungsten Silicide Thin Films, Bharat Pathak

Theses

Micromechanics is a field which is maturing. Recent research interest in micromechanical structures has focussed on the fabrication of microactuators and microsensors. These microsensors and actuators can sense very small changes in the environment without disturbing the equilibrium of the environment. The refractory silicides are some of the compatible materials used to integrate the micromechanical structures and the interfacing electronic circuits on the same chip. As a result of this, the thermodynamic, electrical and mechanical properties of transition metal silicides should be given a closer look for micromechanical applications.

This thesis details the design and fabrication of tungsten silicide moveable …

The Interconnection Network Analysis Package, Nadeem Sabbar

Theses

This thesis focuses on the development of the Interconnection Network Analysis Package (INAP), and the use of INAP to analyze minimal permutation networks. The INAP code is written in C language using Turbo C compiler. Although the INAP has been used to analyze the subject networks it is not a dedicated system. It gives the user the freedom to create the permutation network from scratch (1-8 inputs and 1-7 stages), and then to process it for any number of stages.

The INAP made the analysis of five input networks easy and efficient. The networks have been analyzed stage by stage. …

Design And Simulation Of Submicron Microelectronic Vacuum Triodes, Hou-Jun Wang

Theses

This thesis presents the first design and detailed Simulation of submicron vacuum microelectronic triodes static characteristics. In this thesis a new 5-electrode active device is emphasized.

These devices have potentially important advantages over semiconductor devices. They can be used in extreme environments. The picosecond transit time for internal electron ballistics provide optimism for very fast devices applications. It appears reasonable to fabricate these devices using standard VLSI processing equipment. Further, the micron dimension makes " vacuum microelectronic chips" a reasonable goal.

Devices are characterized for static parameters including electron trajectories, electric field contours, and voltage potential contours. The field emission …

Modeling And Analysis Of Electrical Properties Of Polycrystalline Silicon Films, Yunsheng Wang

Theses

In recent years, investigations on polysilicon grain structures have shown that all polysilicon films by LPCVD which are most used in today's integrated circuits are columnar in structure. In this work, a square columnar grain structure has been considered to model electrical properties of polycrystalline silicon films instead of all previous one-dimensional grain structure models. By solving Poisson's equation with certain boundary conditions, we find that the barrier height at the corners of the grain is lower than that in the one-dimensional case. Assuming the trapping state energy level as constant, we also find that this level has a value …