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Multicriteria Mission Route Planning Using A Parallel A* Search, Michael S. Gudaitis
Multicriteria Mission Route Planning Using A Parallel A* Search, Michael S. Gudaitis
Theses and Dissertations
The Mission Route Planning (MRP) Problem falls into the general class of multicriteria path search problems. Multiple criteria are evaluated to select an optimal aircraft mission route through a hostile environment. Criteria for distance travelled and radar exposure are combined into a single cost function for route evaluation. Radar calculations are performed dynamically. The A* search algorithm is applied to the MRP problem, and a parallel implementation is developed and tested. A unique combination of distributed OPEN lists with a global CLOSED list strategy produced fast execution times on the Paragon. Test cases for scenarios with 15 radars took less …
Using Object-Oriented Database Technology To Develop A Multiple Domain Capability For Domain-Oriented Application Composition Systems, Alfred W. Harris Jr.
Using Object-Oriented Database Technology To Develop A Multiple Domain Capability For Domain-Oriented Application Composition Systems, Alfred W. Harris Jr.
Theses and Dissertations
This thesis describes the design and implementation of a multiple domain capability for a domain-oriented application composition system, named Architect. The research goal was to show how object-oriented database management system (OODBMS) technology can be used to provide simultaneous access to multiple domain-oriented knowledge bases. Since the Architect system was originally designed using the object-oriented paradigm, insertion of OODBMS technology was relatively simple and many of the object-oriented concepts, such as inheritance and aggregation, proved beneficial. Inheritance was used to encapsulate domain knowledge by defining each domain as a subclass of Architect's software architecture. Aggregation was used to allow applications …
Frame Selection Performance Limits For Statistical Image Reconstruction Of Adaptive Optics Compensated Images, Stephen D. Ford
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
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.
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
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
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 …
Computing Norad Mean Orbital Elements From A State Vector, Dwight E. Andersen
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
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
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 …
A Comparison Of Error Categorization Schemes For Use In Software System Safety Programs, Richard Escobedo, Jim Thomas
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
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
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 …
Measurement Of N2+ Mobility In He Via Fourier Transform Emission Spectroscopy, Patrick D. Kee
Measurement Of N2+ Mobility In He Via Fourier Transform Emission Spectroscopy, Patrick D. Kee
Theses and Dissertations
Recently, Hong and Miller used Fourier Transform Emission (FTE) spectroscopy to determine the N2+ mobility in helium by relating the observed Doppler shift of the N2+ (B-X) transition to the measured electric field in the discharge as determined by probes. In order to establish the technique in-house, this effort duplicated that experiment and investigated the sensitivity and utility of the method. Doppler shift measurements in this experiment disagreed significantly with those reported by Hong and Miller. Attempts to reduce the data (and thus determine the mobility) using a model developed by Hong and Miller were unsuccessful. …
Analysis Of Instability Growth And Collisionless Relaxation In Thermionic Converters Using 1-D Pic Simulations, Bret B. Kreh
Analysis Of Instability Growth And Collisionless Relaxation In Thermionic Converters Using 1-D Pic Simulations, Bret B. Kreh
Theses and Dissertations
This work investigates the role that the beam-plasma instability may play in a thermionic converter. The traditional assumption of collisionally dominated relaxation is questioned, and the beam-plasma instability is proposed as a possible dominant relaxation mechanism. Theory is developed to describe the beam-plasma instability in the cold-plasma approximation, and the theory is tested with two common Particle-in- Cell (PIC) simulation codes. The theory is first confirmed using an unbounded plasma PIC simulation employing periodic boundary conditions, ES1. The theoretically predicted growth rates are on the order of the plasma frequencies, and ESl simulations verity these predictions within the order of …
Feasibility Exploration Of Throughfold As A Predictor For Target Loading And Associated Error Bounds, Kris G. Rongone
Feasibility Exploration Of Throughfold As A Predictor For Target Loading And Associated Error Bounds, Kris G. Rongone
Theses and Dissertations
Various applications of the Fredholm integral equation appear m different fields of study. An application of particular interest to the Air Force arises in determination of target loading from nuclear effects simulations. Current techniques first unfold the incident spectrum then determine target loading; resulting spectrum and loading are assumed exact. This study investigates the feasibility of a new method, through-fold, for directly determining defensible error bounds on target loading. Through-fold uses a priori information to define input data and represents target response with a linear combination of instrument responses plus a remainder to derive a quadratic expression for exact target …
Generation Of A Single-Lobe, Far-Field Intensity Pattern From A Laser Diode Array Using An Optical Delay Line, Thomas A. Summers
Generation Of A Single-Lobe, Far-Field Intensity Pattern From A Laser Diode Array Using An Optical Delay Line, Thomas A. Summers
Theses and Dissertations
A simple and practical technique is demonstrated to generate a stable, single-lobe, far-field intensity pattern from a one-dimensional, antiphased, laser diode array with gain-guided elements. The two far-field lobes of the array are combined after introducing an optical delay line into the path of one of the lobes to make the lobes mutually incoherent. The incoherent superposition of intensities produces a near-diffraction-limited, single-lobe, far-field intensity pattern containing 84% of the power, exceeding any previous (known) phase control experiments. This technique compares favorably with more elaborate schemes advanced previously using integrated phase plates, etc. The method is directly applicable to one-dimensional …
Generalized Probabilistic Reasoning And Empirical Studies On Computational Efficiency And Scalability, Eric P. Baenen
Generalized Probabilistic Reasoning And Empirical Studies On Computational Efficiency And Scalability, Eric P. Baenen
Theses and Dissertations
Expert Systems are tools that can be very useful for diagnostic purposes, however current methods of storing and reasoning with knowledge have significant limitations. One set of limitations involves how to store and manipulate uncertain knowledge: much of the knowledge we are dealing with has some degree of uncertainty. These limitations include lack of complete information, not being able to model cyclic information and limitations on the size and complexity of the problems to be solved. If expert systems are ever going to be able to tackle significant real world problems then these deficiencies must be corrected. This paper describes …
An Analysis Of Bayesian Networks As Classifiers, Gregory C. Ahlquist
An Analysis Of Bayesian Networks As Classifiers, Gregory C. Ahlquist
Theses and Dissertations
An analysis of Bayesian networks as classifiers is presented. This analysis results in an algorithm and several tools related to Bayesian network classifiers. The tools calculate and display the decision regions for two level Bayesian network classifiers. They collectively provide an approach to analyze the effects of changing network parameters on the network's decision regions. The algorithm defines a Bayesian network classifier to solve traditional classification problems. The algorithm is data driven, meaning that the resulting Bayesian network classifier is uniquely tuned to the classification problem at hand. Also, the algorithm contains procedures for defining the topology of a Bayesian …
Artificially Intelligent Air Combat Simulation Agents, Daniel E. Gisselquist
Artificially Intelligent Air Combat Simulation Agents, Daniel E. Gisselquist
Theses and Dissertations
The Advanced Research Projects Agency (ARPA), in an effort to improve military simulations, has proposed a standard for Distributed Interactive Simulation (DIS). This network protocol will allow dissimilar applications to communicate simulation information. In the field of air combat, this will allow pilots in remote simulators to fly in a common simulation. The success of this standard is dependent on applications being able to work within that standard, as well as a large variety of Computer Generated Forces (CGFs) to complement interactive forces. CGFs are needed to help simulate the large combat scenarios that can only occur in wartime. By …
Unification Of Larch And Z-Based Object Models To Support Algebraically-Based Design Refinement: The Larch Perspective, Catherine J. Lin
Unification Of Larch And Z-Based Object Models To Support Algebraically-Based Design Refinement: The Larch Perspective, Catherine J. Lin
Theses and Dissertations
This research describes the feasibility of developing object-oriented LARCH specifications, part of a dual approach for formally extending object-oriented analysis models using LARCH and Z. The first phase consisted of two steps establishing a set of transformation heuristics for algebraically representing object models and implementing a robust LARCH parser. The LARCH parser produced abstract syntax trees ASTs of objects forming the basis for analyzing the similarities and differences between Z-based and LARCH-based object representations. The second phase used the analysis of LARCH and Z to identify fundamental core constructs in the languages and abstract syntax trees. These core constructs consisted …
Next Generation Real-Time Systems: Investigating The Potential Of Partial-Solution Tasks, Robert E. J. Caley
Next Generation Real-Time Systems: Investigating The Potential Of Partial-Solution Tasks, Robert E. J. Caley
Theses and Dissertations
While the cyclic executive and fixed-priority scheduling strategies have been sufficient to handle traditional real- time requirements. they are insufficient for dealing with the complexities of next-generation real-time systems. New methods of intelligent control must be developed for guaranteeing on-time task completion for real-time systems that are faced with unpredictable and dynamically changing requirements. Implementing real-time processes as partial-solution tasks is one technique that may be beneficial. This type of task. when combined with intelligent control, has the potential for increasing pre-runtime schedulability, system maintainability. and runtime robustness. This research investigates the benefits of partial-solution tasks by experimentally measuring the …
The Photo-Realistic Afit Virtual Cockpit, Milton E. Diaz
The Photo-Realistic Afit Virtual Cockpit, Milton E. Diaz
Theses and Dissertations
The Air Force Institute of Technology (AFIT) has pursued research in virtual environments since 1988. This research expands the current capabilities of the AFIT Virtual Cockpit (VC) by increasing the realism of the cockpit environment and improving the pilot's command interface. Realism is improved creating console elements from texture maps and polygonal models; these elements include working dials, switches and circuit breakers. The pilot command interface is improved in part by adapting the AFIT Information Pod using a two-dimensional mouse input to the virtual three-dimensional environment. This immersive virtual environment is also improved by modifications to the Head Mounted Display …
Predicting Protein Structure Using Parallel Genetic Algorithms, George H. Gates Jr.
Predicting Protein Structure Using Parallel Genetic Algorithms, George H. Gates Jr.
Theses and Dissertations
The protein folding problem is a biochemistry Grand Challenge problem. The challenge is to reliably predict natural three-dimensional structures of polypeptides. Genetic algorithms (GAs) are robust, semi-optimal search techniques modeling natural evolutionary processes. Fast messy GAs (fmGAs) are variants of messy GAs that reduce the exponential time complexity to polynomial. This investigation evaluates the merits of parallel SGAs and fmGAs for minimizing the potential energy of a pentapeptide, (Met)-enkephalin. AFIT's energy model is compared to a similar model in a commercial package called QUANTA. Differences between the two models are identified and resolved to enhance GAs' abilities to correctly fold …
Parallelization Of The 2d Roe Scheme On The Intel Paragon, John R. Graham Iii
Parallelization Of The 2d Roe Scheme On The Intel Paragon, John R. Graham Iii
Theses and Dissertations
This study presented a methodology for determining the general performance characteristics of a computational fluid dynamics (CFD) algorithm on the Intel Paragon. By performing a rigorous time complexity analysis of a parallel CFD algorithm, the general performance could be characterized before the code was actually parallelized. This was shown by implementing a serial version of the 2-D Roe Scheme on the Paragon. This explicit code was parallelized by the addition of generic yet efficient routines that decomposed the domain, automatically adjusted partition indices, and performed 2-D and 3-D buffer exchanges. Additionally, efficient global routines available for the Paragon were used …
Enhanced Visual User Interface Support For Domain-Oriented Application Composition Systems, Richard A. Guinto
Enhanced Visual User Interface Support For Domain-Oriented Application Composition Systems, Richard A. Guinto
Theses and Dissertations
This research refined the functionality and usability of a previously developed visual interface for a domain-oriented application composition system. The refinements incorporated more sophisticated user interface design concepts1 to reduce user workload. User workload was reduced through window reordering, menu redesign, and Human Computer Interaction techniques such as; combining repetitive procedures into single commands, reusing composition information whenever possible and deriving new information from existing information. The Software Refinery environment, including its visual interface tool INTERVISTA, was used to develop techniques for visualizing and manipulating objects contained in a formal knowledge base of objects. The interface was formally validated with …
Analytic Performance Models For Parallel Discrete Event Battlefield Simulation With Conservative Synchronization, James B. Hiller
Analytic Performance Models For Parallel Discrete Event Battlefield Simulation With Conservative Synchronization, James B. Hiller
Theses and Dissertations
This study investigated the development and use of analytic models for performance analysis of parallel discrete event battlefield simulation using conservative synchronization. A simulation architecture with layered application, simulation, and host machine services provided the model development basis. Simulation entities were modeled with set-theoretic definitions. Deterministic performance models using these definitions were developed for event prediction, scheduling, and execution in sequential battlefield simulation. The sequential model was expanded to include relative bounds for overhead factors introduced when the simulation is spatially decomposed for a parallel distributed memory machine. Comparison of sequential and parallel models instantiated for a simulation with uniform …
Modeiing Operational Task Assignment In Air Force Wing Command And Control, Robert J. Hunt
Modeiing Operational Task Assignment In Air Force Wing Command And Control, Robert J. Hunt
Theses and Dissertations
This research investigated the feasibility of applying software engineering technology to the Air Force wing command and control (C2) domain. As part of this research, domain analysis and object-oriented techniques were investigated and a specific approach was chosen to analyze the domain. Analysis of the domain resulted in an object-oriented domain model that captured the key objects, operations, and associations, and behavior of wing C2. The domain model was used to design and implement a prototype software tool that enables wing decision makers to assign resources to mission tasks and to make assessments about automation's impact on wing C2 operations.
Easy-Sim: A Visual Simulation System Software Architecture With An Ada 9x Application Framework, Jordan R. Kayloe
Easy-Sim: A Visual Simulation System Software Architecture With An Ada 9x Application Framework, Jordan R. Kayloe
Theses and Dissertations
Software architectures increase productivity when used as the basis for developing applications in a problem domain. This thesis describes the creation of Easy-Sim, an object-oriented software architecture for visual simulation systems, and its corresponding implementation as an application framework in Ada 9X. The research built upon ObjectSim, an existing object-oriented simulation architecture implemented as a application framework. Both ObjectSim and Easy-Sim operate on Silicon Graphics platforms and use the IRIS Performer graphics programming library. Easy-Sim is implemented using version 1.83 of the GNAT compiler. The investigation for this thesis involved honing ObjectSim's design, implementing the improved result in both C++ …
Improving Intrusion Detection In Unix-Based Networks, David R. Landry
Improving Intrusion Detection In Unix-Based Networks, David R. Landry
Theses and Dissertations
Computer security has not kept pace with the rapid growth of networked systems. Through its connection to the Internet, the Department of Defense is vulnerable to computer-based attacks. Current intrusion detection systems are still unproven, too complicated, or too costly for most system security officers to implement. The attack methods used by system intruders are known and can be represented as groups of commands called attack signatures. This thesis investigates methods for detecting intruders by monitoring command usage. Testing was conducted in both controlled and uncontrolled circumstances. With controlled testing, it was shown that 7 of the 11 signatures could …