Engineering Commons^™

Finite Impulse Response Filter Design Using Cosine Series Functions, Carlton Delos Bishop

Retrospective Theses and Dissertations

Window functions have been extensively used for the design of SAW filters. The classical truncated cosine series functions, such as the Hamming and Blackmann functions, are only a few of an infinite set of such functions. The derivation of this set of functions from orthonormal basis sets and the criteria for obtaining the constant coefficients of the functions are presented. These functions are very useful because of the closed-form expressions and their easily recognizable Fourier transform. Another approach to the design of Gaussian shaped filters having a desired sidelobe level using a 40 term cosine series will be presented as …

A Study Of The Reaction Kinetics For The Thermal Oxidation Of Dilute N-Heptane Vapors In A Plug Flow Reactor, Steven Hunter Ramsey

Retrospective Theses and Dissertations

During August through October, 1986, experiments were conducted with the aim of devel oping kinetic relationships for the thermal oxi dation of dilute n-Heptane vapors in air using a Lindberg tube furnace reactor. This project was designed to be the first step in the ultimate goal of research ing the effe cts upon the combustion of dilute organic vapors when certain chemicals are added to the combustion stream. These chemicals are postulated to form free radicals and thus enhance the oxidation of organ i cs . Comparison of the kinetics before and after the addition of t he free radical …

Object-Oriented Development Techniques For Real-Time Software Systems: A Case Study, Thomas S. Seldenright

Retrospective Theses and Dissertations

Great improvements have been made in computer technology over the last forty years. Today, systems are being developed to solve complex problems that were previously thought to be out of the reach of computer solutions. Unfortunately, advances in software development techniques have been outpaced by the advances made in hardware development techniques. In recent years, effort has been made to formalize software development techniques suitable for real-time systems. This paper presents an object-oriented approach to realtime systems development. The object-oriented development approach is applied to a real-time case study problem. The case study involves controlling the speed of a toy …

Boundary Layer On A Continuous Flat Plate In Parallel Flow With Similar And Non-Similar Boundary Conditions, Vaughn H.M. Faber

Retrospective Theses and Dissertations

This thesis is a computational analysis of the incompressible laminar boundary layer on a continuous moving surface. The skin friction and heat transfer variations on a moving plate with similar and non-similar (constant) mass transfer at the wall are obtained for 210 cases for the similar boundary solution and 60 cases for the non-similar solution.

Both cases were solved numerically using the fourth order Runge-Kutta algorithm. For the non-similarity case, the local non-similarity method as described by Sparrow, Quack and Boerner was used. The analysis shows that the shear stress for both the similar and non-similar cases is higher when …

Saw Draw: An Interactive Graphical Layout System For Surface Acoustic Wave Devices, Jeffrey Blair Abbott

Retrospective Theses and Dissertations

This thesis introduces a solution to the problem of time and memory space requirements associated with the manipulation/creation of solid state device layout. Through the use of a hierarchical organization of data and a tailored indexing technique, the software described here, referred to as Saw Draw, is capable of manipulating huge amounts of data in a short period of time. This program was written for surface acoustic wave (SAW) device layout but works for a broad range of devices to include semiconductors, microstrip and others.

Due to the large number of details which must be stored for each SAW structure, …

Uniformity Correction For A Scanned Long Wavelength Infrared Focal Plane Array, George C. Heinold

Retrospective Theses and Dissertations

This paper presents an alternative approach in providing uniformity correction for an infrared focal plane array by utilizing analog MOSFET circuitry. This technology is compatible with modern VLSI production and is capable of enhanced operation at cryogenic temperatures. The method presented here is a potential contribution to the growing list of special analog circuit configurations which may be incorporated for on-chip signal processing, inside the cryogenic dewar assembly. Electronic packaging of current thermal systems could be significantly reduced in size and weight by trading some of the cumbersome digital algorithms and complex post-processing circuitry for implementation in VLSI form.

The …

Dynamic Performance-Based Student Model For An Intelligent Simulation Training System, Jenifer M. Sargeant

Retrospective Theses and Dissertations

Student modeling has been the subject of research since the mid-1970's. A student model is an evolving description of what the student knows about the subject domain. Much of the previous research has concentrated on evaluating a student in performing cognitive tasks. The Intelligent Simulation Training System (ISTS) applies the techniques of Artificial Intelligence, Intelligent Tutoring Systems and Expert Systems to simulation-based training. The ISTS Student Model is unique in that it evaluates the student in performance-based tasks. It monitors and records the student's ability to maintain relationships between objects in space and time. The scope of this research was …

A Proposed System For Determination Of Percent Cloud Cover, Carol L. Emrich

Retrospective Theses and Dissertations

A method for determining percent cloud cover by taking two consecutive images using different color contrast filters, specifically a red filter and a blue filter, is described. This method (RF/BF estimate) involves dividing the "red" image by the "blue" image, pixel by pixel, and determining the percentage of pixels in the resultant image with intensity values of one. This is the percent cloud cover. The RF/BF estimate is based on the different effects of molecule and particle scattering of electromagnetic waves in the visible portion of the spectrum. These two types of scattering, Rayleigh and Mie scattering respectively, are described …

The Time Slot Interchange In A Digital Central Office, Khalil George Al-Maalouf

Retrospective Theses and Dissertations

The invention of the telephone and the telegraph opened the door to worldwide corrmunications. Over the years, complex and versatile corrmunication systems have evolved involving many devices and technologies. Switching protocols between switching offices have been established in accordance with the nature of the machines and with the capabilities of the transmission medium and its environment. Switching systems are now stored program oriented, providing a more generalized and digitally oriented internal switching capability. This report will discuss the Time Slot Interchange ( TSI), an important component of the Digital Central Office (DCO). The operation of the send section and the …

The Design Of A Dual Method Metal-Organic Chemical Vapor Deposition System, David B. Cox

Retrospective Theses and Dissertations

For the fabrication of semiconductor devices, solar cells, and infrared detectors, thin film deposition methods are required. Of the deposition methods currently available including MBE, LPE, and MOCVD; MOCVD is preferred due to its relatively low cost per wafer, versatility, and high wafer throughput. Requirements which must be considered in the design of a deposition system are discussed. An MOCVD system is designed such that MOCVD can be carried out by plasma enhanced deposition (PED) or low pressure metal-organic chemical vapor deposition (LPMOCVD). As a result of the inherent characteristics of the two methods, a wide range of operational temperatures …

Display Peripheral For A Flight Simulator Using A Three-Dimensional Computer-Controlled Motor Driven Model, Kenneth Randall Flowers

Retrospective Theses and Dissertations

The flight simulator display peripheral, described herein, provides the visual aide necessary for observation of effects due to operator responses for any aircraft simulator which prohibits the observers from occupying space within the cockpit of the simulator.

This display peripheral is provided by a three-dimensional, computer-controlled, motor-driven model which duplicates the angular movements generated by the aircraft simulator by moving a model aircraft mounted within a clear plastic ball.

The display utilizes a Motorola 68000 educational computer board to translate the three aircraft angles. pitch, yaw and roll received from the aircraft simulator via an RS-232C compatible serial asynchronous communication …

Lansim: A Simulation Package For Estimating Performance Characteristics Of A Class Of Local Area Networks, Gregory Charles Buchner

Retrospective Theses and Dissertations

ABSTRACT During recent years, the trends in computer resource organization have seen the replacement of the traditional mainframe computers and their timesharing terminals with individual desktop workstations. These workstations can offer more computational power than the mainframes of less than a decade ago. With this distribution of processing from the more traditional mainframe computer comes the need to share peripheral resources among these desktop workstations. These include items such as file systems, tape drives, printers, plotters, and graphics display devices. A common way to share these among the multi-computer environment is to provide a transparent gateway that allows each workstation …

Numerical Analysis Of The Resonant States Of Quantum Wells And Superlattice Devices, Alan Gilbert Whittaker

Retrospective Theses and Dissertations

This thesis is concerned with the development of a numerical model to describe the resonant states associated with quantum well and superlattice devices. A numerical method is described where the time-independent Schrodinger equation is represented as a series of simultaneous algebraic equations using the finite-element method. The eigenvalues for these equations are then found using a Sturm sequence, and the eigenfunctions subsequently calculated using a reverse iteration method containing orthogonality constraints. Simulations of specific devices are presented and compared with experimental results and good correlation is observed.

A Cellular Algorithm For Data Reduction Of Polygon Based Images, Robert James Caesar

Retrospective Theses and Dissertations

ABSTRACT The amount of information contained in an image is often much more than is necessary. Computer generated images will always be constrained by the computer's resources or the time allowed for generation. To reduce the quantity of data in a picture while preserving its apparent quality can require complex filtering of the image data. This paper presents an algorithm for reducing data in polygon based images, using different filtering techniques that take advantage of a priori knowledge as to the images' content. One technique uses a novel implementation of vertex elimination. By passing the image through a sequence of …

Heavy Metal Removal By Sedimentation Of Street Sweepings In Stormwater Runoff, Mary Elizabeth Brabham

Retrospective Theses and Dissertations

ABSTRACT Continuous flow column studies were conducted to characterize suspended sol ids and heavy metal reduct ions through sedimentation with varying overflow rates. The heavy metals tested were cadmium, zinc, copper, iron, lead, nickel and chromium. Stormwater derived samples spiked with street sweepings categorized into particle size ranges less than 500 microns in diameter were utilized in the research. Overflow rates investigated ranged from 28 to 3600 gallons per day per square foot. Theoretical predictions of suspended solids reductions with the application of Stoke's Law exceeded observed reductions for the continuous flow system. Performance curves for all reductions over the …

Polar Spectrum Coding, Daniel Harris Chapman

Retrospective Theses and Dissertations

Polar Spectrum Coding is a novel speech coding algorithm for narrowband voice communications. A polar Fourier transform of the signal is computed, and the magnitude and phase of the speech spectrum is encoded for transmission. The correlation between frames of speech signals is exploited to minimize the transmission rate required for intelligible speech. At the receiver, the encoded words are decoded and the spectrum reconstructed. An inverse Fourier transform is performed, and the result is the reconstructed speech waveform. Polar Spectrum Coding theory is explained. The sensitivities of various parameters on performance are explored, and performance in the presence of …

Research And Applications Of Expert Systems In Military Training, Philip Irwin Green

Retrospective Theses and Dissertations

This report surveys recent research and applications of Expert Systems in the military training and simulation community. The report reviews twenty-one recent papers covering this subject. Each paper reviewed has been assigned a class which establishes the phase of development of the system or activities described. For each paper the abstract is given, followed by comments which summarize in more detail significant parameters of the activities reported. This is then followed by a listing of the specific Expert System "areas of interest" described in the paper.

Management Considerations Of Productivity Issues For Local Government, Scott M. Gilbertson

Retrospective Theses and Dissertations

This report examines the issues needed to be addressed by a municipal manager and provides guidelines to follow when establishing a productivity measurement and improvement program. Examined in detail is the relationship of the municipality's quality of service delivery in relationship to productivity. The concerns of productivity in the public sector at the national and local levels are also identified.

Numerous difficulties are encountered when attempting to measure and improve productivity. Many of these difficulties are presented and several are discussed in detail. To overcome the identified difficulties, there are a number of techniques available, some of which are recently …

Laser Induced Darkening Semiconductor Dope Glasses, Jayant Malhotra

Retrospective Theses and Dissertations

No abstract provided.

Direct Digital Control Of A Liquid Level Control Unit, Barbara Viehman Lytle

Retrospective Theses and Dissertations

A system was developed to allow undergraduate engineering students the capability of simulating various types of control modes in a laboratory environment. The use of digital control and common industrail components such as transducers, recorders, and valves was implemented.

Modification to an existing bench scale process control system is outlined and demonstrated. A computer program was written which interfaces with the hardware and data acquisition software allowing the user many options to study control processes under a variety of conditions. A wide range of parameters can be selected. System parameters can be saved on disk or printed directly. Data are …

Finite Element Analysis Of A Glass Fiber Inclusion, Jeffery R. Southland

Retrospective Theses and Dissertations

This analysis investigates the micromechanical behavior of a fiber-reinforced composite. Two realistic deviations from the typical set of simplifying assumptions are considered: nonhomogeneous matrix properties and imperfect fiber/matrix bonds. The stress effects due to a soft matrix interlayer at the fiber interface and the loss of a portion of the fiber/matrix interface bond are examined. The analysis is performed with the ANSYS finite element program. The effects of higher order shape functions and different mesh densities are studied. The final results are compared to a previous analysis performed at Florida Technological University (now University of Central Florida) which utilized a …

An Adaptive Multi-Scene Correlation Algorithm, Paul E. Vogt

Retrospective Theses and Dissertations

Digital scene matching algorithms have been used in both military and commercial image processing systems for years. The trend toward using multiple sensors in military imaging systems has generated anew interest in real time techniques to accomplish sensor fusion tasks such as field of view alignment. This thesis analyzes methods presently in use and introduces a novel algorithm that improves scene correlation performance. The focus of the new technique is in the segmentation area, where significant features are extracted from background and clutter. These performance improvements are especially helpful when the scene contains excessive noise and or lacks detail, a …

Investigative Study Of The Reliability Of A Rotating Turbine Blade, William Stuart Beal

Retrospective Theses and Dissertations

-Turbine blading incidents are a concern to electrical utilities since they can result in power plant unavailability. The reliability of a particular turbine blade is investigated in this report to determine if it can be replaced with a more reliable blade design. The majority of incidents concerning this blade have been attributed to stall flutter vibration that has been the result of unit operation at low load levels with high back-pressures in the steam condenser. Stall flutter can be avoided by limiting back-pressure levels during low load operation and is thus not a concern here. Another potential cause of unreliability …

Continuous Time Convolution Model For Generation Synthetic Hydrographs, Cheryl Brooks

Retrospective Theses and Dissertations

Synthetic hydrographs are often used in stormwater management to provide estimates of peak rate, volume and time distribution of stormwater runoff. A hydrograph model based on the mathematical technique of convolution was developed using an exponential routing response function and the basic watershed continuity equation. After incorporating the model into a computer program, it was calibrated using hydrographs from four urban and three rural watersheds. The watersheds are located in regions of west and south Florida and range in size from 14.7 to 3500 acres. Two other hydrograph models, the Soil Conservation Service's Unit Hydrograph (SCS-UH) mode 1 and the …

Mrp, Jit, And Opt: A Comparison On The Production Floor, Donna M. Denicole Christopher

Retrospective Theses and Dissertations

In order to compete in manufacturing, industry realizes it must work more efficiently with its resources. Three manufacturing techniques have been developed to assist industry in this challenge --MRP, JIT, and OPT. This paper compares these three techniques. It concentrates on the factors that affect production after vendor materials are in-house. A brief discussion of some of the implementation difficulties a company may face during the transition to a new philosophy is also addressed. Finally, a case study of a low volume, highly technical military project is evaluated and analyzed.

Optimization Of Storm Sewer Construction Costs Using A Microcomputer Program, Dawn E. Fetter

Retrospective Theses and Dissertations

When designing a storm sewer system there is a material and labor cost trade-off between changing pipe diameter for a specific flowrate while keeping physical pipe slope constant, and changing physical pipe slope for the same flowrate while keeping the pipe diameter constant.

To calculate costs associated with every possible combination of pipe diameters and excavation depth to find the optimum design for a storm sewer network without the use of a computer would be a very cumbersome task indeed. In fact, a minimum cost solution may never be found.

This paper presents a microcomputer program which assists the engineer …

A Piezoelectric Actuated Scanning Mirror System Utilizing A Type One Control Loop, David Gibbs

Retrospective Theses and Dissertations

The purpose of this thesis is to design and build an improved control loop for a piezoelectric actuated scanning mirror system. A control system has been built having zero steady state position error and an 80 Hertz bandwidth. This was achieved by placing the piezoelectric actuator in the feedback path of an operational amplifier and placing series cascaded notch filters and lead compensators in the forward path of the control loop. A prototype system, including compensation and feedback, is developed. Its performance compares favorably with that of the system model. It is capable of plus and minus 1.7 degrees of …

Axisymmetric Wave Propagation In A Finite Linear Elastic Cylinder, Brian D. Johnson

Retrospective Theses and Dissertations

This work addresses the linear elastic analysis of axisymmetric wave propagation in a finite elastic cylinder. The waves are generated by the Fast Triaxial Device (FTRXD), which fails soil specimens at very rapid rates. The very short duration of the triaxial tests requires the consideration of wave phenomena in the analysis of the test results.

The soil specimens are modeled as linear elastic cylinders which are compressed in the axial direction. The resulting axisymmetric waves are analyzed with the wave equations which are cast in finite difference form, allowing the solution of displacements and stresses throughout the cylinder as a …

Barium Borate In Parametric Oscillation And 1.54 Micron Generation, Mark Kerrigan

Retrospective Theses and Dissertations

As to date, there are several relatively new crystals that have been developed for nonlinear or "parametric" optical applications, including KTP, LAP, KNbO3, m=NA, and BaB204 (barium borate, or simply BBO). The latter crystal, BBO, and the use of BBo to achieve parametric oscillation around an eyesafe wavelength of 1.54 microns is the emphasis of this paper.

Unpublished material includes determining the optimum type of coupling and pump wavelength used when generating 1.54 μm eyesafe radiation based upon Poynting vector walk off, suscpetibilityies, and both signal angular and spectral acceptance widths. Poynting vector walk off curves for linearly polarized extraordinary …

Uniform Energy Discharge For Pulsed Lasers, Eric Calvin Koschmann

Retrospective Theses and Dissertations

The art of achieving a large energy discharge in a controlled manner with relative ease is to use a pulse forming network. Historically the design of such networks generally used a single inductor and capacitor. Although easy to design and implement, this practice does not provide optimum performance in all cases. In particular, most laser welding requires a uniform energy discharge in a pulse to produce a high quality weld. Analysis has shown that when the pulse forming network approximates a lumped constant transmission line a maximum flat pulse is produced with minimal degradation of the pulse rise time. This …