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Theses and Dissertations

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Articles 7771 - 7800 of 8341

Full-Text Articles in Physical Sciences and Mathematics

Data Reduction With Least Squares Differential Correction Using Equinoctial Elements, Michael S. Wasson Dec 1992

Data Reduction With Least Squares Differential Correction Using Equinoctial Elements, Michael S. Wasson

Theses and Dissertations

This study investigates earth satellite orbit estimation on a track of range, azimuth, and elevation data from a single tracking station. The estimation routine is a least squares batch filter based solely on two-body orbital motion. Using equinoctial elements for the reference orbit avoids the numerical difficulties of the classical elements at eccentricities near zero and inclinations near zero or 90 degrees. Orbits for Mir, DMSP, Explorer, Cosmos, and GPS are investigated. The goal of this study is to reduce orbit information from observations (range, azimuth, and elevation) to an element set and a covariance matrix without considering perturbation effects. …

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Solution To A Multicriteria Aircraft Routing Problem Utilizing Parallel Search Techniques, James J. Grimm Iii Dec 1992

Solution To A Multicriteria Aircraft Routing Problem Utilizing Parallel Search Techniques, James J. Grimm Iii

Theses and Dissertations

Pilots select routes based on factors such as threats, fuel, time on target, distance, and refueling points. This is a time consuming task. This thesis presents the software engineering synthesis of a software tool, based on a parallelized A* search algorithm, to select routes. For simplicity only threats and distance are used. A centralized open list is used with one processor managing the list while the other processors perform the node expansions. This decomposition result in a dynamically load balanced system. A number of parameters are changed to study their impact on the execution time. The use of a branch …

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A User Interface To A True 3-D Display Device, Bruce A. Hobbs Dec 1992

A User Interface To A True 3-D Display Device, Bruce A. Hobbs

Theses and Dissertations

This thesis describes an interactive interface to a true three dimensional, real-dm dynamic graphic display, the TI Omniview™. The system generates true 3-D images of volumetric data and objects. The TI Omniview is a cylindrical volumetric laser display that uses a rotating double-helix translucent disk to fill the display cylinder. Voxels are illuminated on the 2-D surface. The rotational speed of the disk allows the viewer to fuse the 2-D images into a true 3-D image. The interface provides the user with a quick and flexible means of manipulating the image generated, the sub-volume displayed, and the resulting 3-D image. …

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The Effect Of An Adaptive Optical System's Spatio-Temporal Response On Imaging Performance, Patrick M. Harrington Dec 1992

The Effect Of An Adaptive Optical System's Spatio-Temporal Response On Imaging Performance, Patrick M. Harrington

Theses and Dissertations

Ideally, an adaptive optical control system would have instantaneous temporal response and infinite spatial bandwidth. In real systems, the response time of the adaptive optical control system is limited by the integration time of the wave front sensor, the computational time of the control algorithm, and the actuator response time. Additionally, finite inter actuator spacing limits the deformable mirror's ability to reproduce spatial frequencies having a period less than twice this spacing. Although analyses general enough to account for both the temporal and spatial characteristics of the adaptive optical system exist, they are complex and require detailed information regarding the …

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Ada Implementation Of An Object Data Repository, Stephen P. Perucca Dec 1992

Ada Implementation Of An Object Data Repository, Stephen P. Perucca

Theses and Dissertations

The many benefits of object-oriented software development such as encapsulation and extendibility have inspired numerous models of the object- oriented paradigm. Rumbaugh's Object Modeling Technique (OMT) is an object- oriented model that uses three submodels. The object, dynamic, and functional submodels of the OMT describe the data, behavioral, and processing aspects of a system by using entity-relationship, state-transition, and data flow models. Cross-links relate how the three submodels tie together. Two metamodels (models of models) of the OMT are developed using the OMT methodology and notation. The essential data elements of the OMT are abstracted into a data metamodel, and …

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A Synthetic Environment Flight Simulator: The Afit Virtual Cockpit, John C. Switzer Dec 1992

A Synthetic Environment Flight Simulator: The Afit Virtual Cockpit, John C. Switzer

Theses and Dissertations

This thesis describes the design and implementation of a part of the Virtual Cockpit: a synthetic environment, distributed network flight simulator. The goal of the project was to prove the concept that this type of flight simulator could fill the gap between high-end, very expensive flight simulators and low-end game quality flight simulators. Discussed are: object-oriented design techniques, multi-processor utilization, the flight dynamics model, synthetic environment technology, the frame-rate vs. realism issue, and the interfaces to a realistic joystick and throttle.

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Design Recovery For Software Library Population, Chester A. Wright Jr. Dec 1992

Design Recovery For Software Library Population, Chester A. Wright Jr.

Theses and Dissertations

This thesis research investigated design recovery as a means of populating a reuse library. The targeted library was part of the Automatic Programming Technologies for Avionics Systems (APTAS). APTAS uses a knowledge base of forms, to present questions to a user, and rules, to select the forms to present and choose existing library modules to use in composing a new system. The approach applied the reengineering model developed by Eric Byrne to accomplish planning for the project, expanded the renovation phase of this model to cover the actual design recovery, and applied the expanded model to populating the library. Using …

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Laser Phase Front Measurements Using A Phase Conjugate Twyman-Green Interferometer, William J. Mandeville Dec 1992

Laser Phase Front Measurements Using A Phase Conjugate Twyman-Green Interferometer, William J. Mandeville

Theses and Dissertations

This study demonstrated the use of a phase conjugate TwymanGreen interferometer for measuring the phase fronts of beams emitted by infrared diode lasers operating at 830 nm. This interferometer successfully measured the phase front of a single element diode laser, providing better resolution than its conventional counterpart. The phase conjugate mirror compensated for aberrations introduced by imperfect optics in the phase conjugating arm of the interferometer. This interferometer was unable to measure the phase front of a diode array due to the array's inability to create a phase conjugate return. The array's short coherence length is believed to be the …

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Generalization And Parallelization Of Messy Genetic Algorithms And Communication In Parallel Genetic Algorithms, Laurence D. Merkle Dec 1992

Generalization And Parallelization Of Messy Genetic Algorithms And Communication In Parallel Genetic Algorithms, Laurence D. Merkle

Theses and Dissertations

Genetic algorithms (GA) are highly parallelizable, robust semi- optimization algorithms of polynomial complexity. The most commonly implemented GAs are 'simple' GAs (SGAs). Reproduction, crossover, and mutation operate on solution populations. Deceptive and GA-hard problems are provably difficult for simple GAs. Messy GAs (MGA) are designed to overcome these limitations. The MGA is generalized to solve permutation type optimization problems. Its performance is compared to another MGA's, an SGA's, and a permutation SGA's. Against a fully deceptive problem the generalized MGA (GMGA) consistently performs better than the simple GA. Against an NP-complete permutation problem, the GMGA performs better than the other …

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Real Image Visual Display System, James R. Brandt Dec 1992

Real Image Visual Display System, James R. Brandt

Theses and Dissertations

This thesis investigates a technique for improving the perception of three-dimensionality in images generated by a Silicon Graphics workstation. The technique involves using a spherical mirror into which the graphics from the CRT are projected. A real image of the graphic is formed by the mirror and it appears to be floating at the image plane. The three-dimensional effect is improved by adding reflections or shadows of the displayed object. Additionally, a method of using real objects with computer generated shadows and computer generated objects with real shadows is investigated. This is done in an effort to quantify how far …

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A Unified Model Of Program Behavior, Douglas T. Michel Dec 1992

A Unified Model Of Program Behavior, Douglas T. Michel

Theses and Dissertations

This thesis is an attempt to account for and unify the three types of locality: temporal, spatial, and structural. A diverse sample of traces are used in measuring program behavior with respect to these localities and a model is presented which represents the memory references a program generates as it goes through execution. The model is validated by estimating, the entropy of a synthetically generated trace and comparing it with actual traces. The results indicate that there is more predictability contained in the original trace than what the model was able to capture. Different variations of the model were tried …

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Entity-Relationship Versus Object-Oriented Modeling And The Underlying Dbms, Kevin J. Routhier Dec 1992

Entity-Relationship Versus Object-Oriented Modeling And The Underlying Dbms, Kevin J. Routhier

Theses and Dissertations

Despite the impressive accomplishments in relational database research, greater support is needed for persistence of the new types of data encountered with object-oriented programming. The concept of object-orientation is not new in the realm of programming; however, its utilization in database management systems is still immature. Regardless of this fact, there is an urgency for object-oriented database technology. With this increase in demand for the next generation databases comes the need to examine object-oriented data modeling versus the conventional entity-relationship modeling of relational database design. This thesis objective is to analyze both paradigms to determine if object-oriented modeling can significantly …

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Electronic-To-Vibrational (E → V) Energy Transfer From Br* To Co2 And Electronic-To-Vibrational (E → V) Laser Feasibility Studies, Steven M. Katapski Nov 1992

Electronic-To-Vibrational (E → V) Energy Transfer From Br* To Co2 And Electronic-To-Vibrational (E → V) Laser Feasibility Studies, Steven M. Katapski

Theses and Dissertations

The energy transfer mechanism from photo-excited bromine atoms (Br(2P½)) to C02 is investigated in a pulsed fluorescence experiment. An excimer-pumped pulsed dye laser operating at 480 nm is used to photolyze molecular bromine, resulting in the creation of one excited state bromine atom, Br(2P½), and one ground state atom, Br(2P3/2). The electronically- excited bromine atoms (referred to as Br*) collide with and excite vibrational modes in the ground electronic state of CO2. Measurements are made of the Br* lifetimes and associated quenching processes, and the …

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Interactive Graphics System For The Study Of Variance/Covariance Structures Of Bivariate And Multivariate Normal Populations, Ronald G. Garlicki Sep 1992

Interactive Graphics System For The Study Of Variance/Covariance Structures Of Bivariate And Multivariate Normal Populations, Ronald G. Garlicki

Theses and Dissertations

This research created a graphics oriented computer program which was used as part of a Visualization, Verbalization, Algorithization and Mathematization (VVAM) learning protocol. The curriculum for this research was the study of variance/covariance structures of bivariate and multivariate normal populations. The program displays the geometric images corresponding to the various possible covariance structures. These images facilitate and encourage experiment-based self discovery learning. The program encourages the student to take an active role in their own education. The program created is self contained, calculating all the statistical values it requires to create the various geometric images. The students have complete control …

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An Environmental Audit Management Plan For The Royal Australian Air Force, Warren L. Lear Sep 1992

An Environmental Audit Management Plan For The Royal Australian Air Force, Warren L. Lear

Theses and Dissertations

The purpose of this research was to develop an Environmental Audit Management Plan (EAMP) tailored to meet the specific requirements of the Royal Australian Air Force (RAAF). The research also examined the resources which would be required to introduce the proposed EAMP into the RAAF. The literature on environmental compliance auditing identifies a number of essential characteristics required for an effective environmental auditing program. These characteristics, in conjunction with the USEPA design guidelines for the development of audit programs for government agencies, were used to guide the development of the RAAF EAMP. Information on Australian environmental legislation, DOD/RAAF policies and …

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Autonomous Face Segmentation, Kevin P. Gay Sep 1992

Autonomous Face Segmentation, Kevin P. Gay

Theses and Dissertations

The purpose of this study was to implement an autonomous face segmentor as the front end to a face recognition system on a Sun SPARCStation2. Face recognition performance criteria, specifically, the capabilities to isolate and resize faces in an image to a consistent scale, were analyzed to determine current practical limitations. Face images were acquired using a S-VHS camcorder. Segmentation was accomplished using motion detection and predefined rules. Tests were run to determine the suitable of the autonomous segmentor as the front-end to a face recognition system. The segmentation system developed consistently located faces and rescaled those faces to a …

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Comparative Evaluation Of A Monocular Head Mounted Display Device Versus A Flat Screen Display Device In Presenting Aircraft Maintenance Technical Data, Jeffrey A. Friend, Randy S. Grinstead Sep 1992

Comparative Evaluation Of A Monocular Head Mounted Display Device Versus A Flat Screen Display Device In Presenting Aircraft Maintenance Technical Data, Jeffrey A. Friend, Randy S. Grinstead

Theses and Dissertations

As military developers provide increasingly complex weapon system, it becomes more difficult for maintenance technicians to perform their jobs. One aspect of the technicians' world is the need to access technical information in the performance of their duties. This study investigated two electronic display systems to evaluate which enhanced technician performance more. A Head Mounted Display (HMD) device and a portable hand-held flat-screen computer were evaluated in the performance of two flightline maintenance activities. Although both display systems were fully portable and self contained, only the HMD system allowed continuous access to technical information during task performance. In most cases, …

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The Application Of Function Points To Predict Source Lines Of Code For Software Development, Garland S. Henderson Sep 1992

The Application Of Function Points To Predict Source Lines Of Code For Software Development, Garland S. Henderson

Theses and Dissertations

This research investigated the results of using function point analysis-based estimates to predict source lines of code (SLOC) for software development projects. The majority of software cost and effort estimating parametric tools are categorized as SLOC-based, meaning SLOC is the primary input. Early in a program, an accurate estimate of SLOC is difficult to project. Function points, another parametric software estimating tool, bases software cost and effort estimates on the functionality of a system. This functionality is described by documents available early in a program. Using a modeling methodology, the research focuses on function point's ability to accurately estimate SLOC …

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Development Of A Standard Set Of Software Indicators For Aeronautical Systems Center, Bradley J. Ayres, William M. Rock Sep 1992

Development Of A Standard Set Of Software Indicators For Aeronautical Systems Center, Bradley J. Ayres, William M. Rock

Theses and Dissertations

This research effort was directed to the development of a standard set of software indicators to be used by ASC. The research was sponsored by ASC/ENASC, who indicated their desire for such a standard set of indicators to allow a database to be developed of program data that would be useful in making predictions about future software efforts. The research began with an attempt to characterize the software indicator environment at ASC, and also to perform a literature search for software indicators currently available. The desired result was an initial core set of indicators useful to software managers and engineers …

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The Development Of An Expert System For Hazardous Cargo Compatibility, Douglas A. Furst, Ronald E. Smith Sep 1992

The Development Of An Expert System For Hazardous Cargo Compatibility, Douglas A. Furst, Ronald E. Smith

Theses and Dissertations

This research demonstrates the application of expert system technology to automate the aircraft load selection process performed when transporting hazardous cargo. The resulting computer program is an expert system named HAZARD. This system incorporates the regulations governing hazardous cargo compatibility with the heuristics used by experts in loadplanning operations. The impetus to develop such a system is the January 1993 conversion of regulation guidelines for hazardous cargo classification and management in Air Force Regulation 71-4, to a universal international standard. The Cargo Operations Division of Headquarters Air Mobility Command at Scott AFB, was concerned that this change in procedures and …

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Examination Of Psychological Type And Preferred Negotiation Tactics And Strategies Of Contract Negotiators, John P. Hebert, Alan J. Meade Sep 1992

Examination Of Psychological Type And Preferred Negotiation Tactics And Strategies Of Contract Negotiators, John P. Hebert, Alan J. Meade

Theses and Dissertations

This research identified the psychological types of government and industry contract negotiators and determined whether their preference for using negotiation tactics and strategies were correlated with their respective psychological types. A survey consisting of the Myers-Briggs Type Indicator (MBTI) and a questionnaire concerning use of negotiation tactics and strategies was mailed to 2,000 contracting professionals of the National Contract Management Association (NCMA). During May and June 1992, 627 usable surveys were received. The MBTI results were paired with the responses to the negotiation tactics and strategies questionnaire. These results were analyzed on a microcomputer using the DBase IV, Excel, and …

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Design Of An Artificial Neural Network Based Tactile Sensor For The Utah/Mit Dexterous Hand, Jeffery D. Nering Sep 1992

Design Of An Artificial Neural Network Based Tactile Sensor For The Utah/Mit Dexterous Hand, Jeffery D. Nering

Theses and Dissertations

The Neural Tactile Sensor (NTS) is a high resolution, easily manufactured tactile sensor consisting of electrodes, a thin resistive 'skin', and pattern recognition circuitry that is capable of resolving dynamic and static contact location, force, and slip throughout the continuum of the sensor's active region. The sensor operates by means of a resistive 'skin' harboring the electric field generated when a current is injected into it, and a plurality of electrodes for taking measurements of said electric field. When current flows through the resistive medium from the location of tactile contact, an electric field within the resistive medium is established, …

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Development Of An Environment For Software Reliability Model Selection, Salah A. Elewa Sep 1992

Development Of An Environment For Software Reliability Model Selection, Salah A. Elewa

Theses and Dissertations

An environment was developed for solving the problem of selecting a proper software reliability model for a given set of software failures. The idea behind the environment developed in this dissertation was to liken a collected set of software failure data to a previous one that proved to fit well with a specified software reliability model. Software failures were assumed to have a two-Parameter exponential distribution with unequal type II censoring. A test criterion was derived for testing Ratio Criterion. The exact distribution of the test criterion was derived. An asymptotic approximation was also obtained and was found to be …

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The Development Of A Performance Measurement Concept For The Royal Australian Air Force, David R. Mcdonald Sep 1992

The Development Of A Performance Measurement Concept For The Royal Australian Air Force, David R. Mcdonald

Theses and Dissertations

he Royal Australian Air Force (RAAF) needed to develop performance measurements (PMs) to support its Program Management and Budgeting (PMB) System. This research assessed the use of the concepts of the Theory of Constraints (TOC) to develop those PMs. The literature indicated that: traditional accounting PMs were not always suitable in an environment of continuous improvement; Activity Based Costing did not provide the required measures; and non-financial PMs were supplanting the older measures. Further, governments faced unique problems in developing PMs, particularly in defining the outcomes to be measured. Using the Critical Theory and Action Research methodologies, and a case …

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Comparison Of Four-Cursor Buttons Vs Joystick To Access Computerized Technical Information From An Integrated Maintenance Information System, Gerald E. Streff, Robert H. Gundel Sep 1992

Comparison Of Four-Cursor Buttons Vs Joystick To Access Computerized Technical Information From An Integrated Maintenance Information System, Gerald E. Streff, Robert H. Gundel

Theses and Dissertations

The purpose of this thesis was to evaluate the use of four-cursor buttons versus a joystick device to present technical order information on a portable maintenance aid computer for aircraft technicians in a maintenance environment. Studies to date have verified the superiority of computer-presented technical orders when compared to current paper-based systems; this research investigated the effectiveness of these computer-based systems when technicians used a joystick or four-cursor button to display desired technical information. A comparison was made as to technician performance using a portable maintenance aid at the 4950th Test Wing, WPAFB OH. A total of thirty-two maintenance technicians …

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Award Fee In Software Acquisition, Mark T. Hunter Sep 1992

Award Fee In Software Acquisition, Mark T. Hunter

Theses and Dissertations

The focus of this research effort was to determine, in general terms, what contractual tools are available to influence contractor performance during the software development process and, specifically, whether or not award fee contracts are appropriate tools. First, a qualitative, in depth literature review was done. Next, personal interviews were conducted with Program Directors and Deputy Program Directors at Aeronautical Systems Center, Electronic Systems Center, and Space and Missiles Systems Center. Then, after the results were summarized, the data was analyzed and findings were made. Findings include: award fee was found to be the most flexible provision in the FAR …

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Photoluminescence Study Of Si1-XGeX/Si And Si/Ge Strained Layer Superlattices, Todd D. Steiner Jul 1992

Photoluminescence Study Of Si1-XGeX/Si And Si/Ge Strained Layer Superlattices, Todd D. Steiner

Theses and Dissertations

In recent years, there has been interest in obtaining efficient photoluminescence (PL) and electroluminescence from Si1-xGex/Si or Si/Ge superlattices. In this dissertation, longperiod c/Si superlattices grown by molecular beam epitaxy at 500°C and annealed post-growth using rapid thermal annealing were investigated using photoluminescence (PL). The as-grown samples have broad PL bands from isoelectronic centers related to Ge complexes as well as sharp near-edge bound exciton lines. The broad PL band was found to be 120 meV below the band gap, after accounting for the effects of confinement of holes. Post-growth annealing resulted in a reduction in …

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Multi-Ion Ambipolar Diffusion, Thomas E. Gist Jul 1992

Multi-Ion Ambipolar Diffusion, Thomas E. Gist

Theses and Dissertations

The continuity and momentum equations for electrons and multiple ion species are solved analytically and numerically using a new model for ambipolar diffusion. The general form of the model is valid for any quasi-neutral plasma for which the diffusion approximation is appropriate, including positive or negative ions, arbitrary geometries, and time dependence. The model provides criteria for determining when single ion diffusion theory is appropriate for describing multi-ion discharges, when a multi-ion proportional model is appropriate, and when a multi-ion nonproportional model is necessary. An expression is developed which provides a necessary condition for proportionality and provides the proportionality constant …

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Design Of A Laboratory Computer Interface, Douglas L. Durand Jun 1992

Design Of A Laboratory Computer Interface, Douglas L. Durand

Theses and Dissertations

An interface for the LSI-11 computer was designed and implemented so that the computer supports data acquisition, data reduction, and equipment control. The design includes both hardware and software and addresses both parallel and serial input/output (I/0). The serial interface's hardware is simply a Serial Line Unit card. This card plugs into the LSI-11 bus and provides the signals necessary to interface EIA RS-232 compatible devices. A software utility was developed to allow communication with the serial device and to allow exchange of data files. Routines were written to allow serial I/O through a FORTRAN program. The interface's parallel hardware …

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Feature Extraction And Classification Of Flir Imagery Using Relative Locations Of Non-Homogeneous Regions With Feedforward Neural Networks, Kevin L. Priddy Apr 1992

Feature Extraction And Classification Of Flir Imagery Using Relative Locations Of Non-Homogeneous Regions With Feedforward Neural Networks, Kevin L. Priddy

Theses and Dissertations

The classification of forward looking infrared (FLIR) imagery is explored using Gabor transform decomposition and relative locations of non- homogeneous regions combined with feedforward neural networks. A feature saliency metric is developed from a Bayesian sensitivity analysis of feedforward neural networks. This metric is then used to reduce the dimensionality of the feature vectors used to identify FLIR imagery without any degradation of classification accuracy. Several system architectures are developed using a roving window combined with a series of Gabor filters to produce feature vectors for presentation to a neural network classifier. One architecture uses the Gabor filter coefficients to …

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