Digital Commons Network^™

A Quantitative Feedback Theory Fcs Design For The Subsonic Envelope Of The Vista F-16 Including Configuration Variation, Scott N. Phillips

Theses and Dissertations

An aircraft's response to control inputs varies widely throughout its flight envelope. The aircraft configuration also impacts control response through variations in center of gravity and moments of inertia. Designing a flight control system (FCS) to accommodate the full flight envelope and configuration set of an aircraft is clearly a complex undertaking. Quantitative feedback theory (QFT) is a design tool which enables the engineer to attack this task in an efficient way. Although QFT is a robust control design technique, it is an interactive algorithm allowing the engineer full control over compensator order and gain. In this research effort, a …

Processing Of Wide-Angle Synthetic Aperture Radar Signals For Detection Of Obscured Ground Targets, Richard J. Sumner

Theses and Dissertations

This thesis investigates advanced processing techniques for the detection of radar targets in the presence of clutter. It is assumed that the radar data available consist of multi-aspect angle, fully polarimetric Synthetic Aperture Radar (SAR) images. Various techniques are introduced and tested on available SAR data. These techniques attempt to exploit the multi-aspect angles in order to extract target characteristics not available in any single image. SAR images are manipulated in such a way to decrease the probability of false alarms in the target detection process. Target detection performance of the techniques is presented and compared. The techniques are shown …

Advanced Formation Flight Control, Michael J. Veth

Theses and Dissertations

In this thesis, the formation flight control problem is continued from four previous theses. Automatic formation flight involves controlling multiple aircraft equipped with standard Mach-hold, altitude hold, and heading-hold autopilots to maintain a desired distance from a lead aircraft or "rabbit". Changes in the rabbit's states are treated as disturbances to the system and rejected. Previous research is advanced in the following areas: Higher-order aircraft-autopilot models are included into the design and a new feedback control law is employed, resulting in more accurate simulations. An energy tracking scheme is developed and is shown to reduce wing aircraft energy excursions. Finally, …

Polarization Sensitivity Of Monopulse Radar Boresight Error Induced By Large, Ogive Radomes, Kelce S. Wilson

Theses and Dissertations

The dependence of Boresight Error (BSE) on incident Electric Field (E-Field) polarization tilt angle is investigated. BSE, defined as the angular difference between a target's actual and radar-indicated position, is influenced by the radome used to protect the antenna. A - reliable computer model for predicting the BSE of electrically large radar-radome systems has been demonstrated and used to investigate the dependence of radome-induced BSE for various combinations of scan angle, element polarization, and incident E-Field polarization. The analysis includes a development of a transmission-depolarization model to justify the results of the computer model. Results compare very well with empirical, …

Perceptual Based Image Fusion With Applications To Hyperspectral Image Data, Terry A. Wilson

Theses and Dissertations

Development of new imaging sensors has created a need for image processing techniques that can fuse images from different sensors or multiple images produced by the same sensor. The methods presented here focus on combining image data from the Airborne Visual and Infrared Imaging Spectrometer (AVIRIS) hyperspectral sensor into a single or smaller subset of images while maintaining the visual information necessary for human analysis. Three hierarchical multi-resolution image fusion techniques are implemented and tested using the AVIRIS image data and test images that contain various levels of correlated or uncorrelated noise. Two of the algorithms are published fusion methods …

A Decision Support Model For Establishing A Plastics Recycling Program, Deven M. Dalcher

Theses and Dissertations

This research focuses on the development of a decision support model for the establishment of a plastics recycling program. The decision support model focuses on identifying the end-product uses and material specifications first. Once the end-product specifications have been identified, the recycling program can be designed. The model will provide solid waste managers an effective decision-making tool to evaluate the economic feasibility of establishing a plastics recycling program.

Design, Fabrication, Modeling, And Optical Characterization Of Organic Polymer Nonlinear Directional Couplers, John N. Berry

Theses and Dissertations

This research was an investigation into the suitability of a recently developed polymer, polyphenylene, as a material for integrated optical circuits (IOCs). Polymers show great promise in the area of IOCs because of material processing advantages, compatibility with most existing integrated circuit technology, and relatively strong nonlinear optical characteristics. This thesis contains an overview of: dielectric waveguides, linear and nonlinear directional coupler theory; various models useful in the design and analysis of optical waveguides; the fabrication of three different waveguide designs; the experimental apparatus and procedure used to optically characterize the waveguides; and the experimental results of the characterization. Waveguiding …

Frame Selection Performance Limits For Statistical Image Reconstruction Of Adaptive Optics Compensated Images, Stephen D. Ford

Theses and Dissertations

The U.S. Air Force uses adaptive optics systems to collect images of extended objects beyond the atmosphere. These systems use wavefront sensors and deformable mirrors to compensate for atmospheric turbulence induced aberrations. Adaptive optics greatly enhance image quality; however, wavefront aberrations are not completely eliminated. Therefore, post-detection processing techniques are employed to further improve the compensated images. Typically, many short exposure images are collected, recentered to compensate for tilt, and then averaged to overcome randomness in the images and improve signal-to-noise ratio. Experience shows that some short exposure images in a data set are better than others. Frame selection exploits …

Flow Visualization Of A Turbulent Shear Flow Using An Optical Wavefront Sensor, Daniel W. Jewell

Theses and Dissertations

The research reported here investigated the use of a shearing interferometer (SI) wavefront sensor to determine the effects of shear-layer turbulence on an optical wavefront. A collimated helium-neon laser beam was propagated through a plane shear-layer produced by mixing helium and nitrogen at different velocities. Since the gases have different indices of refraction, the optical wavefront was distorted by different amounts by each gas. The SI measured the wavefront slope across the sampled area of the wavefront. The shear-layer was viewed from two orthogonal directions. This document contains shadow graphs, interference patterns imaged by each of the SI's six cameras, …

Image Perception Wavelet Simulation And Enhancement For The Visually Impaired, Lemuel Ray Myers Jr.

Theses and Dissertations

This research delves into the area of image enhancement for the visually impaired. Binocular macular degeneration a visual impairment, affects many Americans; since this condition could not be corrected with conventional glasses the literature suggested using an enhancement system which used a pre-emphasis algorithm to enhance the input image for output to the observer. The work of Dr. Eli Peli, a pioneer in the field of image enhancement, is examine and reproduced. Since his work concentrated mainly on frequency analysis of images, the bulk of this research involves using discrete wavelet analysis to augment that work. A biorthogonal wavelet set …

Laser Beam Propagation In Non-Kolmogorov Atmospheric Turbulence, Bruce E. Stribling

Theses and Dissertations

Several observations of atmospheric turbulence statistics have been reported which do not obey Kolmogorov's power spectral density model. These observations have prompted the study of optical propagation through turbulence described by non-classical power spectra. This thesis presents an analysis of optical propagation through turbulence which causes index of refraction fluctuations to have spatial power spectra that obey arbitrary power laws. The spherical and plane wave structure functions are derived using Mellin transform techniques and are applied to the field mutual coherence function (MCF) using the extended Huygens-Fresnel principle. The MCF is used to compute the Strehl ratio of a focused, …

Multispectral Detection Of Ground Targets In Highly Correlated Backgrounds, Jason E. Thomas

Theses and Dissertations

Multispectral detection methods attempt to discriminate targets in a dominant clutter background using multiple images of the same real-world scene taken in different narrow spectral bands in the infrared. Detection is possible due to the empirically observed phenomenon that the radiance of man-made objects, such as a tank or truck, often lies off the main spectral correlation axis of that of natural backgrounds. Radiometric measurements of several vehicles and a tree canopy background taken over three days in June. 1994 were used to examine the factors affecting multispectral detection. Results clearly showed that the processes which provide for higher spectral …

An Improved Heuristic For Intercontinental Ballistic Missile Crew Scheduling, Michael D. Shirley Jr.

Theses and Dissertations

Creating monthly schedules for missile crews is a complex and time-consuming problem. Thousands of events must be scheduled for several hundred missile officers. The rules and regulations governing the problem are numerous, and there are currently no established measures for missile crew schedules. The scheduling software currently available only schedules a fraction of the events. The objectives of this research were to create a rule-based heuristic which could quickly produce feasible or near-feasible schedules, to make the scheduling process paperless, and to develop possible measures of effectiveness for missile crew schedules. The research was successful in each of these areas. …

Computing Norad Mean Orbital Elements From A State Vector, Dwight E. Andersen

Theses and Dissertations

NORAD maintains and disseminates mean orbital elements on Earth-orbiting satellites in the form of Two-Line Element Sets (TLE). Five mathematical propagator models were developed for NORAD's use to predict the position and velocity using TLEs. This study investigated two approaches, Newton's method and direct iteration, to inverting this process by iterating to obtain NORAD-compatible mean orbital elements from a position and velocity state vector and the drag term. The Newton's iteration method was developed but not tested. The less computationally intensive direct iteration method was developed, coded in FORTRAN, and tested. The initial guess and subsequent corrections in the iterative …

Tracking And Impact Prediction Of Earth-Crossing-Objects (Ecos) On A Collision Course With Earth, Gregory A. Bishop

Theses and Dissertations

This study investigated the effectiveness of Earth-based angles only observations in determining the orbit of various hypothetical Earth-Crossing-Objects (ECOs). 'True' trajectories were simulated specifically for Earth-Crossing- Comets (ECCs) by numerically integrating in a Restricted Three Body system. Starting at Earth impact points, the state vectors were reverse-propagated" to a proposed detection time. Observations (obs), with state-of-the-art accuracy, were then simulated with error induced by a Gaussian random number generator; these were used in a least- squares differential corrector to estimate the positions of the ECOs. State vectors and covariance matrices were then propagated to the impact times and axis lengths …

Effects Of Photon Noise On Unconstrained Minimization Techniques For Iterative Blind Deconvolution, Derek K. Davis

Theses and Dissertations

In recent years, imaging through atmospheric turbulence has interested military scientists seeking to improve optical surveillance of satellites. Adaptive optics was a step toward achieving diffraction-limited resolution from ground-based telescopes. Unfortunately, adaptive optics only partially compensate for atmospheric blurring, therefore post processing of images is required. Processing methods in use today require knowledge of the impulse response of the optical system to reconstruct imagery, but this information is seldom known. This thesis looks at a new metal of processing compensated imagery, called blind deconvolution, which assumes very little or no a priori information about the impulse response. In particular, this …

Voice Analysis Using The Bispectrum, Deborah A. Douglass

Theses and Dissertations

The theory of the bispectrum has been studied, though very few practical applications have yet been considered in any depth. One application mentioned in the literature is the use of the bispectrum for voice signal processing. The aim of this thesis was to research the bispectrum towards the particular application of speech enhancement. The technique is based on the fact that the bispectrum is zero for a Gaussian white noise signal, arid the bispectrum of two signals added together is the sum of the two signal bispectra. Theoretically, processing signals in the bispectra domain should increase the signal-to-noise ratio of …

Optimization Of A Nutation Damper Attached To A Spin-Stabilized Satellite, Brady P. Hauboldt

Theses and Dissertations

This study uses linearized equations of motion for a rigid body with an attached spring-mass-damper to maximize the decay rate of a satellite's coning motion. An analysis of the numerical eigenvalues is presented which leads to an optimal relationship between relevant parameters: damper placement, spring constant, damping coefficient, system moments of inertia, and damper mass fraction. The coupled system's eigenvalues do not provide truly critical damping, thus the real eigenvalue parts are minimized in order to achieve damping which requires the minimum amount of time. A comparison between this optimal design method and a classical method concludes a noticeable improvement …

Generic Satellite Monitoring Expert System, Loretta A. Kelemen

Theses and Dissertations

Air Force Satellite Operations is undergoing major changes. Operators no longer receive detailed satellite training, instead they are taught basic fundamentals of satellite operations and expected to control multiple multimillion dollar satellites. The need is clear. An efficient and economical automated system is necessary to assist the satellite operator in his daily tasks of maintaining these DOD priority resources. Satellite intelligent controllers been under R&D since the early 1980s to this need. These systems, however, have focused on the control of one constellation of satellites. In a military striving for efficiency and lower costs, developing a unique intelligent controller for …

Weighting Scheme For The Space Surveillance Network Automated Tasker, Beth L. Petrick

Theses and Dissertations

The purpose of this research is to find the best weighting scheme in the SPADOC 4C Sensor Tasking Prototype. This software, known as the Prototype Tasker, assigns a tasking to each sensor of the Space Surveillance Network. A tasking is a list of objects in which the sensor needs to gather positional data, called observations. One of the inputs to the Prototype Tasker is a user-definable weighting scheme. The goal is to find the weighting scheme that produces the most efficient taskings. This problem was solved using a Simulated Annealing algorithm. The values in the weighting scheme were the variables …

A Methodology To Assess The Utility Of Future Space Systems, Bruce Rayno

Theses and Dissertations

This research identifies the assumptions and simplifications in the SPACECAST 2020 value model and assesses modifications. The model determines and prioritizes future space systems' utility toward controlling and exploiting space. This study shows that the assumption of using an additive utility function is valid. This research shows that the mission areas are mutually utility independent allowing the use of the multiplicative utility function. This research also uses the multilinear function, which requires utility independence implied in mutual utility independence. This study makes modifications to the 98 SPACECAST 2020 measure of merit scoring functions. These scoring functions all used the same …

A Multi-Attribute-Utility-Theory Model That Minimizes Interview-Data Requirements: A Consolidation Of Space Launch Decisions, Raymond W. Staats

Theses and Dissertations

This research uses multi-attribute utility theory (MAUT) to define a mathematical representation of a decision maker's utility associated with a satellite system. While developing the survey instrument, we focused on making it simpler to administer, primarily by eliminating the use of lottery questions. These simplifications enabled us to shorten our interview with the decision maker to under two hours for a rather complex model.

The Junction Characteristics And Current Conduction Mechanisms Of Gainp2 N+P Diodes And Solar Cells, Kitt C. Reinhardt

Theses and Dissertations

This work involves an investigation of GaInP₂ n⁺p diode and solar cell dark current mechanisms, the defect centers that affect these mechanisms, and the response of dark current and solar cell photovoltaic parameters to I MeV electron irradiation and thermal annealing. Dark current due to carrier diffusion, recombination, and tunneling were identified, and recombination current was found to dominate at the maximum power-point voltage of the GaInP2 solar cells. Carrier recombination was found to occur via defect centers at the perimeter and within the bulk of the junction. Two deep majority-hole trap centers were found at E …

A Comparison Of Error Categorization Schemes For Use In Software System Safety Programs, Richard Escobedo, Jim Thomas

Theses and Dissertations

Software safety is becoming increasingly important in the development of DoD advanced weapon systems. To make software safer, hazard conditions must be avoided along with the errors that accompany them. The first step in identifying errors is classifying error data. The area of software error classification is not as advanced as other software development areas. The technical literature lacks examples of comprehensive taxonomies that can be applied to various computer software domains and applications. The predominant approach is to organize errors into categories particular to the program currently in work. The typical error scheme is made of narrow categories that …

A Correlational Study Of The Sei's Capability Maturity Model And Software Development Performance In Dod Contracts, Robert M. Flowe, James B. Thordahl

Theses and Dissertations

The Software Engineering Institute's (SEl's) Capability Maturity Model (CMM) is to measure an organization's software development process maturity. The Department of Defense (DoD) has model with the belief that a more mature software development process will result in a more successful software subject. Although there is a growing body of anecdotal evidence supporting this presumed correlation, there is empirical evidence. Thus, the goal of our research was to determine the nature of the correlation, if any, :ware process maturity and software project success, where process maturity is based on a CMM rating and success based on the parameters of cost …

Factors In Human-Computer Interface Design (A Pilot Study), Susan Stewart

Theses and Dissertations

The DoD has budgeted over $9.8 billion for 1995 for information technology, yet many government office workers let their existing systems sit idle. This thesis explores why these computers are sitting idle. This researcher's initial hypothesis was that certain features of the human-computer interface can positively or negatively affect efficiency, retention, and satisfaction level of workers. Although some research is being done in this area, interfaces continue to be of poor quality, especially in the DoD, where long procurement cycles, forced purchases, and limited budgets result in out-of-date software. Intuitively most programmers know the human-computer interface impacts on a person's …

Selection Of Secondary School Teachers: Perceptions Of School Adminstrators Concerning Criteria, Procedures, And Problems, James Paul Haussler

Theses and Dissertations

Tills study of secondary teacher selection ascertained which selection criteria administrators regarded as important and which criteria were used, ascertained which procedures administrators regarded as important and which procedures were used, and ascertained which problems administrators encountered in selecting secondary teachers. An Analysis of Variance procedure was conducted to ascertain whether differences existed in administrators' perceptions related to the size of school, to the location of the school, and to administrative role.

Data were collected by securing responses to a questionnaire mailed to a stratified (by enrollment size) random sample of 768 public school administrators in North Dakota, South Dakota, …

Perceptions About Assessing And Evaluating Student Performance, Becky L. Melhus

Theses and Dissertations

No abstract provided.

Design And Implementation Of Tools To Increase User Control And Knowledge Elicitation In A Virtual Battlespace, Jim J. Rohrer

Theses and Dissertations

AFIT's Synthetic BattleBridge is an immersive command observatory for viewing large-area activity within a virtual environment. Three basic areas for improvement are addressed: (1) an improved, immersive, user interface, (2) direct control of atmospheric effects, and (3) improved knowledge elicitation by means of remote viewers, a new space scope, and an enhanced RADAR scope. These requirements are analyzed and implemented. Some functionality was lost but the results show a general improvement of environmental control and knowledge elicitation.

Empiricism, Anatomy, Reality: Reading Herman Melville In The Menippean Tradition., Francis Carter Kaplan

Theses and Dissertations

The purpose of the study is to draw together the art of Herman Melville, Menippean satire, and the empirical tradition in English and Scottish philosophy. Historical and biographical concerns serve as a background for exploring Melville's satire of Platonism, transcendentalism, and hermeneutic apriority. Nathaniel Hawthorne, Edgar Allan Poe, and Washington Irving are discussed in this respect. The dissertation also contains related fiction pieces.The dissertation develops several intertwined conceptions of analysis, drawing together an empirical critical basis derived from Ludwig Wittgenstein and "ordinary language philosophy," the notion of satire as criticism, and the exploration of these concepts through an examination of …