Engineering Commons^™

Adaptive Discrete Cosine Transform Image Compression Applied To Visual Flight Simulators, Nancy A. Burrell

Retrospective Theses and Dissertations

A visual flight simulator requires a huge amount of image data to be stored in the database. To make a photo-based system feasible an image compression scheme must be devised to compress the data.

An adaptive discrete cosine transform (DCT) technique is used to compress 24 bit color images to an average of 3 bits per pixel. The bits for the image are distributed based on the relative activity in different parts of the scene. Results and error analysis are presented.

Fate Of Phosphorus From Residential Stormwater Runoff In A Southern Hardwood Wetland, Benjamin M. Fries

Retrospective Theses and Dissertations

The movement and fate of phosphorous inputs from residential stormwater runoff were investigated in a 1.0 hectare hardwood wetland near Sanford, Florida. This wetland receives stormwater runoff from a large residential community through a small shallow canal and provides treatment prior to discharge to Hidden Lake. Field investigations were begun in 1984 and were divided into the following tasks: (1) assessment of the quantity of nutrients and heavy metals entering the wetland by way of stormwater runoff, (2) measurement of the attenuation (3) monitoring of the concentrations of nutrients and heavy metals in groundwaters, (4) accumulation of nutrients and heavy …

Apodization Of Surface Acoustic Wave Three Phase Unidirectional Transducers, Benjamin P. Abbott

Retrospective Theses and Dissertations

This thesis presents an introduction to surface acoustic wave (SAW unidirectional transducer (UDT) apodization. An unbalanced apodization structure is described. The structure is shown to suffer from an unbalanced capacitive effects, significant apodization losses and passband ripple. A balanced UDT structure is developed for the purpose of improving performance and minimizing undesirable effects associated with the unbalanced structure.

Each apodization structure is analyzed and compared using a typical impulse response of a SAW transducer. The analysis is accomplished using SAWCAD2, a unidirectional Surface Acoustic Wave Computer Aided Design FORTRAN-77 program developed at the University of Central Florida. Having shown the …

The Design And Implementation Of Surface Acoustic Wave Devices For Linear Fm And Nonlinear Fm Pulse Compression Technique For Radar Applications, James C. Walker

Retrospective Theses and Dissertations

The purpose of this work is to design, fabricate, and compare dispersive SAW devices using both linear FM and a new non-linear FM scheme. This new non-linear FM scheme uses the Blackman function as the modulating signal of the FM waveform. Up-chirped and V-chirped devices for both linear and the new non-linear FM scheme and their corresponding matched filters are compared.

Design considerations are discussed in detail. An efficient sampling algorithm (which can also be applied to other non-linearly modulated FM waveforms) developed to facilitate the design of the SAW devices is presented.

Simulating The Thermal Behavior An Earth-Stationed Satellite Terminal, Anthony M. Jacobi

Retrospective Theses and Dissertations

Lumped parameter modeling using finite differencing, form the basis for a C language simulation of a thermal system. The study of the earth-stationed satellite terminal includes an introduction to the system, derivation of the governing equation, development of a simulation, and a comparison of the results to empirical data.

The analysis is undertaken with emphasis on the worst-case thermal environment, and with determination of the cooling loads and transient response as primary goals. Comparing the predicted cooling loads to empirical data, and previous analyses, indicates an accurate simulation has been constructed. The computer models are offered as an alternative method …

Editor Design In The Context Of Control System Simulation, Leon Fadden

Retrospective Theses and Dissertations

Advances in microcomputer display devices and support software during the past decade have made the microcomputer an increasingly popular vehicle for technical education. This is especially apparent in the area of simulation. The pedagog can provide the student of control theory not merely with the block diagrams and differential algebra but with high resolution color graphic animations supported by mathematical models whose parameters are easily changed by some editor facility. This mode of control system design and behavior study is both faster and more enjoyable for the student, providing greater continuity, concentration, and learning efficiency.

This paper describes the simulation …

Transient Critical Heat Flux, Kemal O. Pasamehmetoglu

Retrospective Theses and Dissertations

The term Critical Heat Flux (CHF) is used in boiling heat transfer to describe the local value of the heat flux at which a characteristic reduction in heat transfer coefficient first occurs. In today’s technology, the CHF is a phenomenon related to the design and safety of various important devices.

A major limitation on the thermal design of a light-water reactor (LWR) is the necessity to maintain an adequate safety margin between the CHF and the local heat flux. Extended operations at local power levels in excess of the CHF can lead to high temperature oxidation and embrittlement or melting …

Graphics Package For Portable Alphanumerical/Graphics Terminal, Elsie S. Loh

Retrospective Theses and Dissertations

This research report describes the design of a highlevel graphics package for use by application programmers t o display pictures of two-dimensional objects on a portable alphanumeric/graphic terminal. The design is implemented on the Digital VAX-11/780™ minicomputer running under the VMS operating system environment as the host computer and uses the DECwriter Correspondent (LA12) as the graphics device. The graphics package consists both the database manipulation software which is completely device dependent, and the interface software between the normal "drawing functions" and the hardware associated with a particular graphics device, which is minimally device-dependent.

Separation Plane Priority In Computer Image Generation, Keith A. Stump

Retrospective Theses and Dissertations

Flight simulators are devices in which air crews can be trained without the use of actual aircraft. Potentially dangerous maneuvers, such as air-to-air refueling, and destructive exercises, such as evasive action from weaponry or aerial dogfights, can be practiced repeatedly with no risk to pilot or crew. Flight simulators are cost effective since the fuel costs associated with training pilots in actual aircraft can be excessive. Flight simulators offer an alternate training method with reduced cost. The task of a visual flight simulator is to present the trainee with scenes representative of those that would be seen if the actual …

Interactive Texturing For A Computer Graphics Display System, Yin L. Wah

Retrospective Theses and Dissertations

Surfaces have texture, and few surfaces are truly smooth in the real world, yet this is how they are modeled. Texturing provides the illusion of increased surface roughness or granularity, and it also gives the illusion of extra detail and realism. This is accomplished by modulating surface color based on gradient function known as texture pattern.

Changing texture pattern data can be expensive and time consuming since the change must be done on database offline system and then reloaded on the Computer Image Generator (CIG) for review of the change. The Interactive Generator (IAT) system is designed for online examination …

Setting Time Standards In A Service Environment: A Case Study, Nael H. Hasweh

Retrospective Theses and Dissertations

One of the most important and costliest resources a hospital has are its personnel and their productivity. Almost invariably, they offer the greatest opportunities for cost containment.

This report is the result of a study conducted in the maintenance department at a local hospital. The objective of the study was to design and implement a work measurement system that is capable of producing accurate time standards. Comparison of actual times reported by employees with these standards would then be used to produce accurate productivity measures.

The proposed system is explained in detail, and the results obtained by implementing such a …

Interactive Micro-Computer Software For The Production Of Engineering Drawings, Brian R. Garvey

Retrospective Theses and Dissertations

This project has developed a microcomputer-based interactive Graphics Software System for the production of engineering drawings. The drawings, stored in a digital format, can be recalled and updated much faster than by using conventional drawing methods. This allows for increased production and a standardized drawing format.

The system was designed to be easy to use so that with little training, a user can create, edit, plot, and save drawings for later retrieval. In addition, an open architecture was used in the design of the drawing database and program command structure so that the system can be easily expanded upon as …

Feasibility Investigation Into The Use Of A Liquid Crystal Television As A Spatial Light Modulator, Edward R. Raudenbush

Retrospective Theses and Dissertations

The recent availability of inexpensive, electrically addressable liquid crystal displays has generated interest in the use of such devices for optical processing applications. Characterizations pertinent to this use include: maximum obtainable modulation depth, modulation transfer function (MTF), linearity of response, refresh cycle time and optical flatness. Examples of device performance as a coherent processor and as an incoherent processor will be given.

Non-Linear Plane Stress Analysis Using The Finite Element Method, Habib Amirzadeh

Retrospective Theses and Dissertations

Purpose of the Study

The objective of this report is to check the Neuber and Linear rules, and to find the percent differences in comparison with the plane stress and plane strain solution using the non-linear finite element method. All the data are based on the maximum stress concentration where the crack forms and the material behaves non-linearly. This particular problem has been solved using ANSYS, which is a general purpose finite element program.

Life Prediction

Another purpose, which is not the main subject of this report, is to use the result from Neuber and Linear rules to predict the …

A Theoretical Evaluation Of Water Surface Changes In A Circular Reservoir, Hossein G. Tehrani

Retrospective Theses and Dissertations

The purpose of this project is primarily to develop an equation to estimate the time that it will take for the water surface to decrease to another depth in an inverted conical-shaped reservoir behind an earth dam by means of the falling head permeability concept. This equation can be applied to the earth embankment either with or without underdrain. Since the derived equation for time span is a complicated and tedious matter, a computer program has been developed for solving this equation.

The computer program is written in BASIC language and executed on a Tektronix 4051 microcomputer. Primary effort has …

Distribution Of Lead And Zinc In Groundwater Around An Exfiltration Pipe Including A Study Of Specific Conductance, Donna M. Schiffer

Retrospective Theses and Dissertations

Highway runoff is a significant source of nonpoint pollution to surfoce and ground waters. Underground disposal of stormwater has several advantages, such as recharge of ground water resources and reduction of flow rates at existing storm sewer outfa11s. However, there are few studies on the effects of underground disposal of stormwater on the qua1ity of ground water. The purpose of this stucty was to examine the changes 1n lead, zinc, and specific conductance in highway runoff that is routed to an underground disposal facility as the water passes through the unsaturated soil to the surficia1 aquifer. An exfiltration pipe in …

Design Considerations In The Development Of An Automated Cartographic System, Robert L. Holden

Retrospective Theses and Dissertations

Cartography, the art of producing maps, is an extremely tedious job which is prone to human error and requires many hours for the completion of maps and their digital data bases. Cartography is a classic example of a job that needs to be automated. Through the new advances in image processing and pattern recognition, the automation of this task is made possible with the cartographer acting as a supervisor. This paper reviews current cartographic techniques, and examines design considerations for a fully automated cartographic system. The benefits of such a system would be improvements in speed, flexibility, and accuracy. The …

A Computer Simulation Of An Incoherent Optical Processor For Spatial Frequency Analysis, Randall T. Stratton

Retrospective Theses and Dissertations

A computer simulation demonstrates the feasibility of a technique for performing spatial frequency analysis on an incoherent scene in one dimension using an electronically addressable spatial light modulator (SLM). By applying biased sinusoidal variation to the SLM transmittance, the real and imaginary parts of the Fourier transform are available and readily yield both magnitude and phase of the Fourier transform.

In addition to the Fourier transform this simulation investigates the use of a simple binary pulse train transform for the sake of reducing system complexity and increasing speed of operation.

The Effect Of Thickness On Neuber's Rule For Estimation Of Fatigue Life, Shahram Elmi

Retrospective Theses and Dissertations

To predict the fatigue life of a notched member from a strain-life curve, the high strain concentration at the root of the notch must be known. For determining this high (post yield) strain, the Neuber’s Rule (for plane stress) and linear rule (for plane strain) can be applied. To investigate the accuracy of these method a notched member which is subjected to fully reversed cyclic loading is analyzed by the finite element method. Moreover, members with different thicknesses are analyzed with three dimensional elements, and a correlation between plane and three dimensional data is obtained. This correlation may be used …

Direct Sequence Spread Spectrum Acquisition Design, John C. Fakatselis

Retrospective Theses and Dissertations

Spread spectrum communication techniques are utilized to provide transmission of signals which have anti-jamming properties, a low probability of being intercepted, and can support a multiple-access system by servicing simultaneously a number of channels. This thesis concentrates on the receiver acquisition problem of a transmitted signal which is the output of a spread spectrum communication system. The acquisition requirements of a spread spectrum system and also the general approaches to the problem of “active and passive correlation” are discussed. A unique general purpose all-digital acquisition hardware design is developed and described to the schematic level of detail, where specific parts …

A Zero Extraction And Separation Technique For Surface Acoustic Wave And Digital Signal Processing Fir Filter Implementation, Keith V. Lindsay

Retrospective Theses and Dissertations

Presented is a new method of separating the zeros of a Finite Impulse Response (FIR) filter producing optimal digital filter of surface acoustic wave (SAW) design implementation. Overviews of zero extraction algorithms and of FIR filter design using the Remez Exchange algorithm are presented (McClellen et al. 1973).

The computer aided design (CAD) procedure presented allows the designer to specify the general filter characteristic which the Remez algorithm translates to FIR time domain coefficients. These coefficients are readily translated to the frequency (z) domain, producing an Nth order polynomial in z. The characteristic polynomial is factored to determine all roots …

Automated Q-Factor Measurement Via A Network Analyzer, Fadi E. Ayoub

Retrospective Theses and Dissertations

An algorithm is developed for the HP automated network analyzer that can determine the three basic parameters of microwave cavity resonators: the unloaded resonant frequency fo, the unloaded Q-factor Q_o, and the coupling coefficient β. The input reflection coefficient of the resonator is measured via the network analyzer, which is driven by an HP desk computer. The graphical techniques (Smith Chart) are replaced by the much faster calculations on the computer using numerical techniques. Stirling and Bessel’s formulas, in conjunction with the central difference interpolation method, are used to interpolate between sampled points to enhance the accuracy …

A Peripheral Subsystem Optimized For Computer Image Generation Applications, John J. Bloomer

Retrospective Theses and Dissertations

Requirements for ever increasing realism in real time computer image generation for military mission and commercial training, have generated the need for a higher performance, more cost effective front-end processor. Current computer image generators front-end general purpose computers are reaching their performance limits in current architectures.

The tasks of this processor include: realtime computations, magnetic disk control, data transfer and direct memory access to and from the balance of the image generator. A new front-end processor system is under development. This multiple-bus, multiprocessor architecture in and of itself does not address disk and external data transfer. A peripheral subsystem is …

Dynamic Systems Analysis Of A Vehicle Suspension System, Bruce M. Skeldon

Retrospective Theses and Dissertations

This research report deals with one system in a Computer Aided Instruction package in the Dynamic Systems and Control Theory fields for the college undergraduate students. It uses the computer to numerically solve the two degree of freedom equations of motion for a vehicle suspension system. Numerical solutions to the system differential equations are used to drive an animated display of the vehicle’s motion (vertical displacement and rotation about the center of gravity) on the video display terminal.

A One Step Collision Detection Method For Computer Graphics Programs, Gregory T. Eichner

Retrospective Theses and Dissertations

The topic of this thesis is a collection detection algorithm for use in computer programs dealing in three dimensional graphics. Collision detection is usually accomplished by breaking the movement into small steps and checking if a collision has occurred at each of these discrete steps. This method is a very time-intensive way to detect for collisions and therefore, inefficient for a system which typically moves in large increments. For this kind of system, a method could be developed which checks once for collisions without dividing the move into multiple small increments. The subject of this paper is an algorithm, developed …

Companding Flash Analog-To-Digital Converters, Michael P. Brig

Retrospective Theses and Dissertations

This report will demonstrate how a companding flash analog-to-digital converter can be used to satisfy both the dynamic range and resolution requirements of an infrared imaging system. In the past, infrared imaging systems had to rely on analog electronics to process a thermal image. This was costly and, in many ways, inefficient but the only way to perform the function. Digital processing was impractical because ADC conversion speeds were slow with respect to video frequencies. Furthermore, it is impossible to gain the necessary dynamic range using linear conversion techniques without large digital wordlengths. Therefore, the principles of companding flash analog-to-digital …

Direct Digital Control Of A Liquid Level/Temperature Control Unit, Pedro J. Claudio

Retrospective Theses and Dissertations

A direct digital control algorithm was implemented on a liquid level and temperature control unit. Two control schemes were implemented on the system and the results were compared against a fourth order Runge-Kutta solution.

Both control schemes involved proportional feedback with dynamic adjustment of the operating point. It was found that the control scheme that contained a feedforward component which dealt with the inlet water temperature had a superior dynamic response to setpoint changes. Steady state offsets in both control schemes were attributable to model parameter estimation errors. Differences between the actual and predicted system dynamic response were also attributable …

Multi-Computer Communication With Crossbar Switches, Teh-Cheng Song

Retrospective Theses and Dissertations

This thesis describes the design and implementation of a MC6809 multi-computer communication system, which includes a hardware communication controller, with emphasis on the system's software development. A communication program written in 6809 assembly language has been developed to interface each user and the controller. The communication program acts as a postman, sending and taking messages for each user via the interrupt-driven sending and receiving software. A message is transmitted over a crossbar switched path, which is 8 bits wide, to increase the transmission rate and decrease dedicated CPU time. Every time MC6809 microcomputer in the system can send or receive …

Pulse Width Modulated Adaptive Delta Modem Design And Analysis, Gregory L. Milne

Retrospective Theses and Dissertations

A unique design of a voiceband adaptive delta modem will be presented. The modulator utilizes a constant amplitude variable width pulse combined with the principles of delta modulation. This results in a modem that has lower amplitude distortion, requires less transmission channel bandwidth, and is less prone to slope overload than conventional adaptive delta modems. The design also allows the use of a simple single integration demodulator while maintaining fidelity.

The modem design and analysis is presented assuming a transmission channel which is bandwidth limited and amplitude limited.

A Performance Comparison Of Solar Radiation Predictive Models For Both Fixed And Tracking Surfaces, William F. Marion

Retrospective Theses and Dissertations

Accurate performance prediction for a system utilizing solar energy requires accurate estimates of the solar radiation received by the collector surface. This thesis compares the performance of five different diffuse solar radiation models in estimating the diffuse radiation received by a tilted surface in the warm, humid climate of Central Florida.

The following models were studied: Isotropic Model, Temps and Coulson Model, Klucher Model, Hay Model, and Perez Model. The models were evaluated for both a fixed south facing surface and for three different tracking schemes suitable for photovoltaic applications. Model estimates were then compared to the solar radiation data …