Digital Commons Network^™

The Design And Fabrication Of Dielectric Waveguides For Use With High Power Carbon Dioxide Lasers At 10.6 Microns, Jong Min Kim

Theses

The feasibility of constructing a feasible transission system to propagate 10.6 microns energy from a CO₂ laser is explored. The system is to be used in a clinical surgical setting to deliver as much as 100 watts of CW power from a surgical CO₂. laser to a surgical target.

The optimal transmission system is a slender flexible cylindrical structure, 1 mm in diameter and 1.5 m long. The structure should be sufficiently flexible to be bent into a 5 to 10 cm radius without a significant increase in the attenuation constant. For clinical applications the system must …

Digital Signal Processing Implementing The C Language With Graphics Spectrum Analysis Display, Anuraksa Mahanirananda

Theses

Digital Signal Processing discussed in this thesis is concerned with the transformation of signals or complex wave forms From time domain to frequency domain and vise-versa, implemented on microcomputer systems. The primary principles are: speed of transformation, ease of usage as an application program, capabilities of graphics displaying transformed data (such as power spectrum analysis), storing these data onto record files, and capability of using these data Files and programs with other application programs.

We begin by discussing briefly, the concepts of Fourier theory, Discrete and Fast Fourier Transform, algorithms of Fast Fourier Transform and bit-reversal. Then we implement these …

Performance Of Second Order Delta Modulation System, Reza Aghazadeh Alavi

Theses

The performance of an ordinary delta modulation (DM) system under three types of input signals was investigated. These signals were band limited Gaussian noise, 800 Hz sine wave, and speech signal. The affects of 2nd DM added to the ordinary DM in improving the performance of the system were researched. This is called a Second Order Delta Modulation System. The obtained data showed an increase of about 3dB in the overall Signal to Noise Ratio (SNR) of the system, in the worse case.

Input to the 2nd DM is the band limited error of the first DM. A linear phase …

Optically Phased Laser Transmitter, Janet S. Fender, Salvatore J. Cusumano, Robert R. Butts, Christopher R. Dehainaut

AFIT Patents

An apparatus and technique are described for phasing the outputs of a multiplier telescope array used as a laser transmitter. The technique uses samples of the transmitted beams to control optical path lengths through the separate telescopes so that the beams add coherently at the receiver. The phasing concept is applicable both to systems which provide inputs to the multiple telescopes by dividing a single laser beam and to systems in which the inputs to the telescopes and multiple, phase-locked laser beams. The approach is also compatible with single line and multi-line lasers, and it does not entail stringent alignment …

Computer Simulation Of Dynamic Systems, Charles G. Smith

Retrospective Theses and Dissertations

Computer simulation of a control system is a valuable tool in design or performance evaluation. This is especially true when non-linear elements cannot be ignored and must be included within the model. A general purpose block diagram oriented simulation program will be developed which can utilize continuous, discrete and non-linear building blocks. The software tool will be demonstrated by means of an example.

Maximum-Likelihood Estimation Of Time-Varying Delay-Part I, John A. Stuller

Electrical and Computer Engineering Faculty Research & Creative Works

This Paper Presents, for the First Time, the Exact Theoretical Solution to the Problem of Maximum-Likelihood (ML) Estimation of Time-Varying Delay d(t) between a Random Signal s(t) Received at One Point in the Presence of Uncorrelated Noise, and the Time-Delayed, Scaled Version as(t - d(t)) of that Signal Received at Another Point in the Presence of Uncorrelated Noise. the Signal is Modeled as a Sample Function of a Nonstationary Gaussian Random Process and the Observation Interval is Arbitrary. the Analysis of This Paper Represents a Generalization of that of Knapp and Carter [1], Who Derived the ML Estimator for the …

Comment On "Orientation, Alignment, And Hyperfine Effects On Dissociation Of Diatomic Molecules To Open Shell Atoms", Mark D. Havey, Linda L. Vahala

Electrical & Computer Engineering Faculty Publications

A recent paper in this journal [Y. B. Band e t a l., J. Chem. Phys. 8 4, 3762 (1986)] reported parameters describing orientation and alignment produced, in an axial recoil limit, by one photondissociation of diatomic molecules. Reported also were values, applicable to the resonance transitions of the alkali atoms, for orientation and alignment depolarization coefficients. Most of the numerical values reported for the coefficients were incorrect, in some cases by as much as a factor of 2. We report a tabulation of correct depolarization coefficients applicable to the resonance transitions of common alkali isotopes. Further, the coefficients …

Compiling Unit Clauses For The Warren Abstract Machine, George D. Herbert

UNF Graduate Theses and Dissertations

This thesis describes the design, development, and installation of a computer program which compiles unit clauses generated in a Prolog-based environment at Argonne National Laboratories into Warren Abstract Machine (WAM) code. The program enhances the capabilities of the environment by providing rapid unification and subsumption tests for the very significant class of unit clauses. This should improve performance substantially for large programs that generate and use many unit clauses.

Design Of Multivariable Deadbeat Controllers Using Reduced Order Models, Joaquin Alberto Zuniga

Masters Theses

"This study is concerned with the design of minimum Frobenius norm deadbeat controllers using reduced order models. Deadbeat controllers force the non-zero initial states of a linear multivariable discrete time system to the origin of the state space in minimum time. A controller of minimum Frobenius norm achieves such response with least effort.

The deadbeat controllers are designed on the basis of eigenspectrum assignment. In general, this approach permits a freedom in the selection of the closed-loop Jordan matrix which is used in the design of parametric controllers.

In this presentation, it is demonstrated that the task of deadbeat controller …

Polarizing Beam Splitters For Infrared And Millimeter Waves Using Single-Layer-Coated Dielectric Slab Or Unbacked Films, R. M.A. Azzam

Electrical Engineering Faculty Publications

No abstract provided.

Metal Waveguide Modeling Of Tapered Quadratic Index Media, Lee W. Casperson, Bahram Zandi

Electrical and Computer Engineering Faculty Publications and Presentations

The basic electromagnetic properties of tapered graded index fibers are equivalent to the properties of a class of concave metallic waveguides. Although useful in their own right, such metal waveguides also provide a straightforward and inexpensive means for studying the characteristics of more complicated tapered media.

Thin-Film Beam Splitter That Reflects Light As A Half-Wave Retarder And Transmits It Without Change Of Polarization: Application To A Michelson Interferometer, R. M.A. Azzam

Electrical Engineering Faculty Publications

The refractive index n₁ of a transparent layer of quarter-wave optical thickness coating a transparent substrate of refractive index n₂ can be chosen to produce half-wave retardation (HWR) in reflection and no change of polarization in refraction at any angle of incidence ø. The function n₁(ø, n₂), and the associated polarization-independent reflectance of the film-substrate system R(ø, n₂) are determined. Such a coated surface can be used as a beam splitter with excellent characteristics (e.g., split fractions that do not depend on source polarization, a split beam whose polarization is identical …

Wind Streamline Ambiguity Removal Of Microwave Scatterometer Data, Hans W. Zaepfel

Electrical & Computer Engineering Theses & Dissertations

There is a class of satellite microwave scatterometers that return oceanographic information which includes wind vectors with directional ambiguity. The first part of the ambiguity removal process is to reduce the data to a directional ambiguity of 180°. This thesis shows that wind direction change contains the information required for streamline ambiguity removal and that syntactic pattern recognition techniques can be used to locate the areas of wind direction change. Spreading the information along the areas of wind direction change results in the removal of the streamline ambiguity. The algorithm is implemented and the results are presented showing that it …

An Investigation Of Overvoltage Effects On A Gas-Blown Spark Gap, Michael Steven Mazzola

Electrical & Computer Engineering Theses & Dissertations

This experimental investigation addresses the anomalous overvoltage breakdown and subsequent recovery characteristics observed in gas-blown spark gaps. Previous investigations have reported a two-stage recovery process in self-break, pulse-charged, gas-blown spark gape in which the spark gap recovers first to an intermediate breakdown strength before recovering to the undisturbed breakdown voltage. The recovery process has been explained in terms of two different characteristic times. The first is that required to obtain initial recovery in which the spark gap regains its intrinsic breakdown strength. The second time is that required to obtain final recovery in which the pulse-charged spark gap regains the …

Multi-H Continuous Phase Modulation : Its Properties And Analysis, Jyung-Cheng Chen

Theses

Multi-h CPM, a generalization of CPFSK and also one of the so-called Combined Modulation and Coding schemes, is useful in digital communication systems where both the bandwidth and power are constrained. The increased signal processing complexity, which can be viewed as the third communication resource, is used to trade for both power and bandwidth, and to approach the error-free communication promised by Shannon's theorem.

The transmitted multi-h CPM signal carries a coded sequence of continuous phase changes; the possible phase states form a cylindrical trellis in phase and time, in which the modulation indices are reused in a cyclical fashion. …

Relationship Between The P And S Fresnel Reflection Coefficients Of An Interface Independent Of Angle Of Incidence, R. M.A. Azzam

Electrical Engineering Faculty Publications

The Fresnel reflection coefficients r_p and r_s of p- and s-polarized light at the planar interface between two linear isotropic media are found to be interrelated by (r_s - r_p)/(1 - r_sr_p) = cos 2β, independent of the angle of incidence ø, where tan²β = ∊ and ∊ is the (generally complex) ratio of dielectric constants of the media of refraction and incidence. This complements another relation (found earlier), (r²_s - r_p)/(r_s - r_sr_p) = …

The Acquisition Of Direct Sequence Spread Spectrum Communication Systems, Anthony Donald Demeri

Theses

This Paper surveys different techniques of acquiring Direct Sequence Spread Spectrum Systems.

It classifies different systems, indicates the strongpoints and weakness of each, along with some applications.

One method, The Single Dwell Serial PN Acquisition System is then focused on in detail. The detail includes analysis of standard version, derivation of the mean time to acquire, the variance, the probability of detection and the probability of a false alarm.

In the last section of the paper the analytical results of the Single Dwell Serial PN Acquisition System shall be confirmed by computer simulation.

The Dielectric Slab-Wedge Antenna, B. Keith Christensen

Theses

A theoretical model and numerical investigation of the directive gain of a dielectric slab-wedge radiator is presented. The model is based on a union of the classical dielectric slab equations, local mode theory, and equivalent current distribution treatments of the truncated dielectric slab and wedge geometries.

The far field is developed from the sum of two current distributions. The slab region, up to the transition plane between slab and wedge, is replaced by equivalent electric and magnetic surface current densities. The wedge contribution is developed from a volume polarization current distribution.

Conservation of power is used to approximate the field …

Replacement Of Surface Ducted Rays Near Caustics With Guassian Beams, Carlos Javier Ruiz

Theses

Conventional approach to a solution of a wave propagation problem in an inhomogeneous medium is to utilize either rays or modes to represent the wave field. Asymptotic ray theory (ART) starts to fail in the vicinity of caustics due to rays experiencing many reflections. Even uniform representations do not properly correct this deficiency of rays when caustics start to pile up in the far range. One possible alternative is to replace these rays with modal bundles and remainders [1]. A promising technique using Gaussian Beams has been used to represent the total field due to a point or a line …

Ray And Beam Representation Of The Glancing Phenomena, Michael Sotiriou Vogas

Theses

Asymptotic ray theory (ART) is a widely used method dealing with problems of wave propagation in an inhomogeneous medium. The main deficiency of ART is in transition regions where rays near caustics, glancing and critical incidence fail to represent the actual wave field. Ray bundles in such transition regions have been successfully replaced with modal bundles and remainders El] in well defined profiles. However , in practical problems it is difficult to implement modal representations and almost impossible to express remainders. Recently emerging Gaussian beam method (GBM) has shown promising results in representing the total field produced by a source …

Linearization Accuracy In Probabilistic Load Flow, Guan-Zhong Liang

Theses

This paper presents a linear load flow method which can be used for probabilistic load flow analysis. The method is based on least-square estimation. To estimate its accuracy in linear load flow calculations, the method and a previously developed linear load flow method are applied to a typical power system and the results evaluated. Comparable accuracy is noted.

On-Line Analysis Of Highly Coherent Brain Activity During Transcendental Meditation And Automated Biofeedback, Deepak Dinkerrai Rawal

Theses

Occurance of highly coherent brain activity (EEG) specific to the meditation has been reported in the literature. The present thesis is an effort to look into the mechanics of meditation using the recent technique of analysis of high coherence in the EEG. Based on previous work, reporting increased EEG coherence during practice of Transcendental Meditation, a closed loop model and hypothesis is proposed using biofeedback to close the loop. The hypothesis proposes that very high coherence in the EEG is a very significant neurophysiological parameter, reflecting instantaneous quality of meditation in the form of an average high coherence above threshold. …

Nervous System Simulation, Jian Chen

Theses

This thesis deals with the nervous system simulation. The Hodgkin-Huxley model and Stein's model are used as basic tools. The author has tried to describe some practical problems by mathematical models.

First, the horse-shoe crab eye is investigated. Light intensity is reported to the brain by the firing frequency of the photoreceptoe. A Poisson process is used to simulate the stimulus to the receptor. The result of the stochastic model coincides with the theoretical one: receptor overlapping decreases the resolving power of the eye; and the lateral inhibition compensates the effect of overlapping.

Second, a nerve muscle model was set …

Maine Yankee Shutdown Assessment: A Report To Governor Joseph E. Brennan, Maine State Planning Office

Maine Collection

Maine Yankee Shutdown Assessment: A Report to Governor Joseph E. Brennan

Maine State Planning Office, Maine Office of Energy Resources, Maine Public Advocate

Executive Department - May 1986

Contents: Legal Process / Decommissioning Constraints and Costs / Public and Economic Costs and Benefits / Apprendices

Two-Step Optimal Thermal Generation Scheduling, B Fardanesh, F. Eugenio Villaseca

Electrical and Computer Engineering Faculty Publications

A new approach to the solution of the optimal thermal generation scheduling problem is presented. The problem is solved in two steps. As a first step, the optimal production schedule for the next day is obtained based on a daily load forecast, reserve capacity requirements, and present status of generating units. The second-step algorithm uses the results of the first step and adjusts the previous schedule to meet new constraints developed during the course of the day. Variable truncation dynamic programming is proposed as a new method to reduce computation effort. To eliminate the need for solving the …

Laser Pump And Probe Excited State Absorption Measurements, Shawpin Jong

Electrical & Computer Engineering Theses & Dissertations

A pump and probe technique was used to investigate triplet-triplet excited state absorption in solutions of the scintillators 2,5 diphenyloxazole (PPO) and 2,1 naphthyl,5 phenylzole (a-NPO) in several solvents.

KrF excimer radiation (248 nm) was used to pump the samples under investigation as well as a tunable dye laser which was used as the probe. Time-resolution was obtained by changing the optical path difference between the pump and probe beams.

Transient excited state absorption was measured in a wide spectral region between 330 nm and 600 nm, showing a peak at 400 nm for PPO solutions, and two …

Optimization Of Reactive Ionized Cluster Beam (R-Icb) Technique For Deposition Of Gan Films, Veronica S. Kyriacou

Theses

The deposition of GaN film onto glass substrate, using the Reactive - Ionized Cluster Beam deposition technique was studied. The creation of clusters is dictated by various parameters such as the vacuum pressure inside and outside the crucible, the crucible temperature, and the nozzle diameter of the crucible. Optimization of these parameters was experimentally studied, and deposition of gallium films on glass substrates was tried as a first step.

The direct heating method was used at first to get the 1100¬1300°C crucible temperature which was required for the creation of gallium clusters. Although different tungsten wire diameters and different number …

A Microsequenced Prolog Inference Engine, Jeffrey J. Ferguson

Retrospective Theses and Dissertations

Prolog is a symbolic logic language presently emerging among numerous expert system designs. The architecture for a microsequenced Prolog machine (UPM) capable of providing the basic language features to a host computer is proposed. The Prolog machine functions are portioned into three processor components – Input/Output, Memory, and Central (CPU), where the design of the Central Processor is emphasized. Detailed discussion outlines the CPU facilities used to implement the forward-chaining and backtracking functions for the UPM. The UPM features are compared to the PLM-1, a microsequenced Prolog inference engine under development at University of California, Berkley. An emulation of the …

Data Structure Implementation And Investigation For A Prolog Language Interpreter, Hector Iurcovich

Retrospective Theses and Dissertations

A developmental Prolog language interpreter is constructed in the C programming language. The data type format is a subset of that of the Project Aquarius Prolog Engine proposed and under development at the University of California, Berkley. The design of the Prolog interpreter is part of an investigation at UCF in design of expert system architecture for real time applications. The interpreter facilities of data structure definition and manipulation are developed and applied. The list data structure is used as an example data structure. The scheme for representing structured data is based on the Lisp cons cell. Run-time generated lists …

An Exact Analysis For Efficient Computation Of Random-Pattern Testability In Combinational Circuits, Sharad C. Seth, Bhargab B. Bhattacharya, Vishwani Agrawal

School of Computing: Conference and Workshop Papers

Experimental evidence shows that low testability in a typical circuit is much more likely due to poor observability than poor controllability. Thus, from theoretical and practical standpoints, it is important to develop an accurate model for observability computation. One such model, in terms of supergates, is proposed in the first part of this paper thus complimenting our earlier work. It is now possible to obtain exact random-pattern testability for each line in a circuit.

The second part of the paper analyzes the supegate structure of a circuit from a graph theoretic viewpoint. Finding a supergate is related to determining the …