Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network™

Open Access. Powered by Scholars. Published by Universities.®

Air Force Institute of Technology

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 4801 - 4830 of 5600

Full-Text Articles in Entire DC Network

Accelerating Conservative Parallel Simulation Of Vhdl Circuits, Joel F. Hurford Dec 1994

Accelerating Conservative Parallel Simulation Of Vhdl Circuits, Joel F. Hurford

Theses and Dissertations

This research effort considers heuristic and cost model based techniques for the optimal partitioning of VHDL circuits for parallel simulation. Correlation statistics are gathered on a wide variety of graph-based a priori parameters. Linear regression is used to identify significant parameters for inclusion in a representative cost model. Driving a greedy search, this cost model is used to improve upon initial heuristic partitions. The influence of feedback dominated previous research so a no-feedback algorithm is used to create the initial partition The circuits studied range from 1,050 to 4,243 gates.

Go to article

Modeiing Operational Task Assignment In Air Force Wing Command And Control, Robert J. Hunt Dec 1994

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.

Go to article

Unification Of Larch And Z-Based Object Models To Support Algebraically-Based Design Refinement: The Z Perspective, Kathleen M. Wabiszewski Dec 1994

Unification Of Larch And Z-Based Object Models To Support Algebraically-Based Design Refinement: The Z Perspective, Kathleen M. Wabiszewski

Theses and Dissertations

This research established a foundation for formalizing the evolution of based object models to theories, part of a dual approach for formally extending object-oriented analysis models using the Z and LARCH languages. For the initial phase, a comprehensive, consistent, and correct Z language parser was implemented within the SOFTWARE REFINERY™ Programming Environment. The Z parser produced abstract syntax trees (ASTs) of objects, thereby forming the basis for analyzing the similarities and differences between the based and LARCH-based object representations. The second phase used the analysis of the two languages to identify fundamental core constructs that consisted of similar syntactic and …

Go to article

A Correlational Study Of The Sei's Capability Maturity Model And Software Development Performance In Dod Contracts, Robert M. Flowe, James B. Thordahl Dec 1994

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 …

Go to article

Factors In Human-Computer Interface Design (A Pilot Study), Susan Stewart Dec 1994

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 …

Go to article

The Re-Engineering Of The Air Force Institute Of Technology Student Information System, Douglas J. Wu Dec 1994

The Re-Engineering Of The Air Force Institute Of Technology Student Information System, Douglas J. Wu

Theses and Dissertations

This research describes the design and implementation issues associated with re-engineering the Air Force Institute of Technology Student Information System (AFITSIS). Currently, AFITSIS executes on aging relational database technology and has unfriendly user interface mechanisms. The two research objectives met were to research current AFITSIS requirements, design, and implementation, and use object-oriented methods to design an alternative implementation based on proposed object database management system standards. This research explores how AFITSIS performance and capabilities might be enhanced by taking advantage of new object-oriented software engineering techniques. One of the primary benefits of this research is a detailed object modeling technique …

Go to article

A Numerical Model To Predict The Fate Of Jettisoned Aviation Fuel, Karl D. Pfeiffer Dec 1994

A Numerical Model To Predict The Fate Of Jettisoned Aviation Fuel, Karl D. Pfeiffer

Theses and Dissertations

While airborne, military and civilian aircraft must occasionally jettison unburned aviation fuel into the atmosphere. This research investigates the fate of a jettisoned fuel (e.g. JP-4, JP-8, etc.) from initial release to final ground fall by numerically modeling the physical phenomena governing the fate of this fuel: evaporation, advection, and dispersion. Using previous work in evaporation and free fall of fuel droplets as a foundation, this thesis presents an integrated evaporation advection and dispersion model designed to run under the resources of a typical personal computer. This integrated model is capable of using near real-time meteorological data (i.e. vertical profiles …

Go to article

Improving Intrusion Detection In Unix-Based Networks, David R. Landry Dec 1994

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 …

Go to article

Designing And Implementing An Ada Language Binding Specification For Odmg-93, Stephen R. Lindsay Dec 1994

Designing And Implementing An Ada Language Binding Specification For Odmg-93, Stephen R. Lindsay

Theses and Dissertations

Object-oriented database management systems (ODBMSs) represent the latest advancement in database technology, combining the reusability and maintainability of the object-oriented programming paradigm with the ability to efficiently store and retrieve a wide range of data types as well as code to manipulate stored data. Unfortunately, programmers developing software in the Ada programming language do not have the ability to interface to object databases without significant customized code development. One important reason for this has been the absence of a standard defining the constructs accessing ODBMS functionality. This thesis documents the creation of an Ada language binding to the ODMG-93 standard …

Go to article

Modeling Workload Effectiveness And Efficiency Of Air Force Wing Command And Control, Michael D. Sarchet Dec 1994

Modeling Workload Effectiveness And Efficiency Of Air Force Wing Command And Control, Michael D. Sarchet

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 of wing C2. The domain model was used to design and implement a prototype software tool that enables wing decision makers to make assessments about automation's impact on wing C2 operations.

Go to article

Analysis And Simulation Of Narrowband Gps Jamming Using Digital Excision Temporal Filtering, Gerald L. Falen Dec 1994

Analysis And Simulation Of Narrowband Gps Jamming Using Digital Excision Temporal Filtering, Gerald L. Falen

Theses and Dissertations

The purpose of this thesis is to investigate the performance of the Digital Excision Temporal Filter (DETF) to reject narrowband jammers used against the Global Positioning System (GPS). The DETF takes the Fast Fourier Transform (FFT) of the GPS signal and excises any FFT bins that are above a preselected threshold level. Then the excised signal is Inverse Fourier Transformed and fed to the GPS receiver. Several jammer types are simulated including Continuous Wave (CW), Pulse CW, Swept CW, Narrowband Spot Noise, and Wideband Barrage Noise jammers. Cases are also simulated using all but the Wideband Barrage Noise jammer at …

Go to article

Classification Of Ultra High Range Resolution Radar Using Decision Boundary Analysis, Christopher L. Eisenbies Dec 1994

Classification Of Ultra High Range Resolution Radar Using Decision Boundary Analysis, Christopher L. Eisenbies

Theses and Dissertations

This thesis examines the discrimination of targets with Ultra High Range Resolution (UHRR) radar data. Using these measured signals from frontal aspect angles of four aircraft classes, the baseline performance of the Adaptive Gaussian Classifier (AGC) is tested with respect to aligning exemplars to templates. Alignment plays a crucial role in the AGC's classification performance which can degrade by 11% for a target class. The AGC is compared to non-parametric classifiers, but no statistically significant degradation of performance is found. Data separability is analyzed by hounding the Bayes error. The data is well separated in a statistical sense. A feature …

Go to article

Development Of A Mammographic Image Processing Environment Using Matlab, John L. Kelley Dec 1994

Development Of A Mammographic Image Processing Environment Using Matlab, John L. Kelley

Theses and Dissertations

Breast cancer is a disease that accounts for a disturbingly large number of deaths in females each year. Its prevalence is a topic of concern to all of us since it can affect our families, friends, and coworkers. Although mammographic screening is the most effective method currently available for the early detection of breast cancer, it is far from being an infallible procedure. Mammographic reading is error prone, partly because of the complexity of the task and partly because of the variability in human performance. Computers offer high reproducibility, and when used as an adjunct by the radiologist, may improve …

Go to article

Minimizing The Impact Of Synchronization Overhead In Parallel Discrete Event Simulations, Andrew C. Walton Dec 1994

Minimizing The Impact Of Synchronization Overhead In Parallel Discrete Event Simulations, Andrew C. Walton

Theses and Dissertations

A Parallel Discrete Event Simulation Coprocessor was designed for conservative synchronization protocols and was implemented in software using some of a parallel computer's nodes to act as coprocessors. The coprocessor was designed to offload synchronization overhead and next event queue management from the nodes running the simulation. The coprocessor was designed to accelerate simulations based on the Simulation Protocol Evaluation on a Concurrent Testbed with ReUsable Modules (SPECTRUM) environment. The research was conducted in three steps: the SPECTRUM environment was ported from an Intel iPSC-2 to an Intel Paragon XP-S, the coprocessor was designed and the simulations were timed, with …

Go to article

Easy-Sim: A Visual Simulation System Software Architecture With An Ada 9x Application Framework, Jordan R. Kayloe Dec 1994

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++ …

Go to article

Multiple Model Adaptive Estimation And Head Motion Tracking In A Virtual Environment: An Engineering Approach, James E. Russell Dec 1994

Multiple Model Adaptive Estimation And Head Motion Tracking In A Virtual Environment: An Engineering Approach, James E. Russell

Theses and Dissertations

Software engineering tools and techniques were applied to design and implement an application that reduces lag typically present in virtual environment displays. The application was a Multiple Model Adaptive Estimator (MMAE), composed of three Kalman filters, that predicted head orientation one sample period into the future. The environment rendering software used these predictions to generate the environment display. Each of the filters in the MMAE was designed for a different assumed head motion type (benign, moderate, or heavy), which allowed the MMAE to adapt to changes in head movement characteristics. The use of Ada 9X as an implementation language for …

Go to article

Roc Analysis Of Ir Segmentation Techniques, Georgia K. Harrup Dec 1994

Roc Analysis Of Ir Segmentation Techniques, Georgia K. Harrup

Theses and Dissertations

Receiver Operating Characteristic (ROC) curves are used to compare the effectiveness of IR image processing techniques. Two non-parametric error estimation techniques (k-Nearest Neighbor and Parzen Window) are used to create estimates of the probability density functions for the data. These pdfs are used in the creation of the ROC curves for both resubstitution and leave-one-out estimates. These estimates generate the upper and lower bounds, respectively, on the ROC curves. The ROC curve analysis is performed on the outputs of various image processing techniques and the resulting ROC curves are used to compare the techniques. Of the image processing techniques used …

Go to article

Isolated Digit Recognition Without Time Alignment, Jeffrey M. Gay Dec 1994

Isolated Digit Recognition Without Time Alignment, Jeffrey M. Gay

Theses and Dissertations

This thesis examines methods for isolated digit recognition without using time alignment. Resource requirements for isolated word recognizers that use time alignment can become prohibitively large as the vocabulary to be classified grows. Thus, methods capable of achieving recognition rates comparable to those obtained with current methods using these techniques are needed. The goals of this research are to find feature sets for speech recognition that perform well without using time alignment, and to identify classifiers that provide good performance with these features. Using the digits from the TI46 database, baseline speaker-independent recognition rates of 95.2% for the complete speaker …

Go to article

A Quantitative Feedback Theory Fcs Design For The Subsonic Envelope Of The Vista F-16 Including Configuration Variation, Scott N. Phillips Dec 1994

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 …

Go to article

Processing Of Wide-Angle Synthetic Aperture Radar Signals For Detection Of Obscured Ground Targets, Richard J. Sumner Dec 1994

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 …

Go to article

Polarization Sensitivity Of Monopulse Radar Boresight Error Induced By Large, Ogive Radomes, Kelce S. Wilson Dec 1994

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, …

Go to article

Perceptual Based Image Fusion With Applications To Hyperspectral Image Data, Terry A. Wilson Dec 1994

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 …

Go to article

A Decision Support Model For Establishing A Plastics Recycling Program, Deven M. Dalcher Dec 1994

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.

Go to article

Design, Fabrication, Modeling, And Optical Characterization Of Organic Polymer Nonlinear Directional Couplers, John N. Berry Dec 1994

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 …

Go to article

Satellite Surface Material Composition From Synthetic Spectra, Eugene L. Caudill Dec 1994

Satellite Surface Material Composition From Synthetic Spectra, Eugene L. Caudill

Theses and Dissertations

The objective of this research was to determine if measurements from a Sagnac interferometer could provide reliable estimates of satellite material composition. The Sagnac interferometer yields a spatial interferogram that can sampled by a linear detector array. The interferogram is related to the spectrum of the source through a Fourier transform. Here, spectral reflectivities of nine common satellite materials were used to simulate the spectrum on obtains from an ideal Sagnac interferometer in the beam-train of a ground-based telescope whose mission is to view satellites. The signal-to-noise ratio of the spectrum was varied to simulate the effect of range variation …

Go to article

Frame Selection Performance Limits For Statistical Image Reconstruction Of Adaptive Optics Compensated Images, Stephen D. Ford Dec 1994

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 …

Go to article

Flow Visualization Of A Turbulent Shear Flow Using An Optical Wavefront Sensor, Daniel W. Jewell Dec 1994

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, …

Go to article

Image Perception Wavelet Simulation And Enhancement For The Visually Impaired, Lemuel Ray Myers Jr. Dec 1994

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 …

Go to article

Laser Beam Propagation In Non-Kolmogorov Atmospheric Turbulence, Bruce E. Stribling Dec 1994

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, …

Go to article

Multispectral Detection Of Ground Targets In Highly Correlated Backgrounds, Jason E. Thomas Dec 1994

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 …

Go to article

First Prev Next Last