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 5251 - 5280 of 5596

Full-Text Articles in Entire DC Network

Defining Contract Terms, Michael J. Cushing, Mary R. Spalding Sep 1992

Defining Contract Terms, Michael J. Cushing, Mary R. Spalding

Theses and Dissertations

The goal of this research effort was to develop consensus definitions for fifty-one (51) contracting-terms. This was accomplished by developing a synthesized definition for each term based on a review of the available published literature, subjecting the synthesized definitions to expert scrutiny via a survey distributed to recognized contracting professionals, and amending the literature-based definitions as indicated by the survey responses. Using this approach, consensus was achieved on all but one term. The consensus definitions developed in this way are recommended for inclusion in a comprehensive dictionary of contracting terminology, to be comprised of the results of this and other …

Go to article

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 …

Go to article

A Methodology For Project Selection Using Economic Analysis And The Analytic Hierarchy Process, Jeffrey L. Battin, Thomas J. Bender Sep 1992

A Methodology For Project Selection Using Economic Analysis And The Analytic Hierarchy Process, Jeffrey L. Battin, Thomas J. Bender

Theses and Dissertations

This study examined the applicability of a multiple criterion decision making method, known as the Analytic Hierarchy Process (AHP) , to economic analysis decisions involving project selection. Through a survey of the literature and current practices, it was determined that qualitative criteria were not adequately represented in a typical economic analysis of projects. Several MCDM methods were examined and the AHP was found to be the most promising technique to rate projects on a ratio scale. Two types of project selection problems, those involving nonmutually exclusive alternatives and those involving mutually exclusive alternatives, were examined. It was determined that the …

Go to article

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 …

Go to article

Estimating The Operating And Support Cost Difference Between Royal Australian Air Force C-130e And C-130h Hercules Aircraft, Terrence J. Sidey Sep 1992

Estimating The Operating And Support Cost Difference Between Royal Australian Air Force C-130e And C-130h Hercules Aircraft, Terrence J. Sidey

Theses and Dissertations

This research investigated the operating and support cost (O & S cost) of Royal Australian Air Force (RAAF) C-130E and C-130H aircraft. The purpose was twofold: to provide information about the relative O & S cost of the RAAF's old and "new" C-130 aircraft; and to increase knowledge and understanding of aircraft O & S costing within the RAAF. Preliminary research indicated that RAAF O & S costing was rudimentary and that suitable O & S data would be difficult to obtain. Accordingly, an analogous O & S cost system -- the U.S. Air Force (USAF) SABLE cost model and …

Go to article

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 …

Go to article

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 …

Go to article

The Detection And Correlation Modeling Of Rayleigh Distributed Radar Signals, Alan L. Buterbaugh Sep 1992

The Detection And Correlation Modeling Of Rayleigh Distributed Radar Signals, Alan L. Buterbaugh

Theses and Dissertations

This thesis provides a method for determining the detection of partially correlated Rayleigh distributed radar returns by a pulsed search radar. The receiver consists of a quadrature demodulator receiver, followed by a square law envelope detector and a linear post-detection integrator. In addition, a technique for determining the pulse-to-pulse correlation of a complex target is given using inverse Fourier transforms of the target scattering centers. An AIM-9 missile is used to illustrate how the partially correlated detection techniques and the pulse-to-pulse correlation predictions can be used to determine the probability of detection. The Detection and Correlation Modeling of Rayleigh Distributed …

Go to article

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 …

Go to article

Speech Recognition Using Visible And Infrared Detectors, Patrick T. Marshall Sep 1992

Speech Recognition Using Visible And Infrared Detectors, Patrick T. Marshall

Theses and Dissertations

A system has been developed that tracks lip motion using infrared (IR) or visible detectors. The purpose of this study was to determine if the additional information obtained from the IR or visible detectors can be used to increase the recognition rate of audio Automatic Speech Recognition (ASR) systems. To accomplish this goal, several hardware analog prototypes had to be designed, built and tested. Different detectors (IR and visible) and modes of operation (active and passive) were tried before a reliable and useful signal was found. An analog-to-digital (A/D) board was then designed and built that digitized both the microphone …

Go to article

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 …

Go to article

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 …

Go to article

A Modal Analysis And Modelling Of A Lightly Damped Large Space Structure, Scott E. George Jun 1992

A Modal Analysis And Modelling Of A Lightly Damped Large Space Structure, Scott E. George

Theses and Dissertations

This study involves the modification to the PACOSS Dynamic Test Article to create a lightly damped representative large space structure with closely spaced, low frequency modes. An experimental modal analysis is performed to recharacterize the low frequency flexible vibration modes. A finite element model is created using MSC/NASTRAN to predict low frequency behavior using both real eigenvalue analysis and frequency response analysis. Then a reduced order model is created and fine-tuned to represent the dynamics of the structure for the identified low frequency modes.

Go to article

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 …

Go to article

A Method For Determining Schedule Delay Information In A Channel Cargo Route Network Schedule, Justin E. Moul Jun 1992

A Method For Determining Schedule Delay Information In A Channel Cargo Route Network Schedule, Justin E. Moul

Theses and Dissertations

This research develops a method for measuring schedule effectiveness by determining the amounts of enroute, cargo delay caused by a given aircraft mission schedule. The method is designed to generate information which helps identify flights for which different scheduling might decrease overall cargo delay in the entire network, given that all non-scheduling factors are held constant. The research uses a simplified twelve-airport cargo route network to test the methodology.

Go to article

Wing Rock Prediction Method For A High Performance Fighter Aircraft, Robert C. Nolan Ii May 1992

Wing Rock Prediction Method For A High Performance Fighter Aircraft, Robert C. Nolan Ii

Theses and Dissertations

This study is a limited investigation of the nonlinear aircraft behavior known as wing rock. An eight state F-15 model is analyzed using bifurcation theory. The wing rock onset point is identified and small perturbation analysis is used to linearize the equations of motion about this point. The eigenstructure of the model is analyzed and is used to identify the stability modes involved in this motion. A procedure is developed to predict wing rock onset and frequency and the critical stability derivatives involved in this motion are identified. The developed procedure is applied to existing F-4J data and a flight …

Go to article

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 …

Go to article

Comparison Of Synchronization Techniques For The Afit Direct Sequence Spread Spectrum System, Edward A. Bednar Apr 1992

Comparison Of Synchronization Techniques For The Afit Direct Sequence Spread Spectrum System, Edward A. Bednar

Theses and Dissertations

The purpose of this study is to analyze and evaluate the performance of several code synchronization methods that could be used in the Air Force Institute of Technology's (AFIT) Direct-Sequence Spread Spectrum (DSSS) communication system. These methods include the sliding correlator, transmitted reference, sequential estimation, and three types of matched filters. The matched filters are the baseband matched filter, delay line matched filter, and the convolver. The criteria used for the evaluation of these synchronization methods are theoretical synchronization times and probability of bit-error. Advantages and disadvantages of each synchronization method are described and a method is recommended to be …

Go to article

Hardware-Verification Through Logic Extraction, Michael A. Dukes Mar 1992

Hardware-Verification Through Logic Extraction, Michael A. Dukes

Theses and Dissertations

A Prolog-based system is described which employs logic-extraction to perform hardware-verification. The extraction rules are built automatically from hierarchical structural VHDL models, enabling the equivalence of a structural VHDL description and a layout specification to be verified. Pin-to-pin critical- path analysis is performed within the logic-extraction process; many noncritical paths are pruned early, making pin-to-pin critical path analysis of large circuits feasible. It is demonstrated that a design methodology based on logic extraction, VHDL, and a layout tool can provide a fabricated functionally- correct IC design without circuit-level or switch-level simulation. This methodology is shown to be practical for VLSI …

Go to article

Numerical Analysis Of Plasma Transport In Tandem Volume Magnetic Multicusp Ion Sources, Todd R. Vitko Mar 1992

Numerical Analysis Of Plasma Transport In Tandem Volume Magnetic Multicusp Ion Sources, Todd R. Vitko

Theses and Dissertations

A one-dimensional fluid model of plasma transport in tandem volume magnetic multicusp ion sources is explored. The model, the positive ion source code pos, by Glasser and Smith, calculates plasma density, drift velocity, electron temperature, and ion temperature in an ion source. The usefulness of the model is limited: (1) The plasma density trend runs opposite to experimental results, and electron temperatures are an order of magnitude higher than experimentally observed. (2) simplification of the reaction chemistry leads to a plasma balance between ionization and outflow instead of the correct balance between ionization and recombination. (3) Wall losses are …

Go to article

Development Of A System For Survey Of Radon Concentration Of The Dayton Area Using A Liquid Scintillation Counter And Analysis Of The Data, Taewon Kim Mar 1992

Development Of A System For Survey Of Radon Concentration Of The Dayton Area Using A Liquid Scintillation Counter And Analysis Of The Data, Taewon Kim

Theses and Dissertations

A system to do a large scale survey was developed. The data obtained from the survey was analyzed using a database. The database incorporated an equation for converting cpm into radon concentration pCi/ℓ). The equation of conversion, protocol for measuring radon concentration, survey form, and a database program were modified (from previous theses) or developed for this thesis. The elution time constant, adsorption time constant, and calibration factor were calculated for equation of conversion. Two surveys were during the course of the thesis. On the first survey, the arithmetic average radon concentration with standard error of the mean was 2.9 …

Go to article

An A Priori Multiobjective Optimization Model Of A Search And Rescue Network, Joseph C. Imsand Jr. Mar 1992

An A Priori Multiobjective Optimization Model Of A Search And Rescue Network, Joseph C. Imsand Jr.

Theses and Dissertations

The purpose of this study was to determine the most robust frequency assignment for a search and rescue network. The focus was to assign weights to the transmitter areas of the network to determine which weight sequence produced the most robust frequency assignment. The DoD furnished weight sequences for twelve two-hour time blocks. These weight sequences were compared to a weight sequence with all weights having equal value. Network and linear programming were used to-solve this problem and generate frequency assignments for all weight sequences. Classical and tolerance sensitivity analysis were used to analyze the frequency assignments generated by the …

Go to article

Shock Tube Simulation By The Smooth Particle Hydrodynamic (Sph) Method, Luke A. Lorang Mar 1992

Shock Tube Simulation By The Smooth Particle Hydrodynamic (Sph) Method, Luke A. Lorang

Theses and Dissertations

A smooth particle hydrodynamic code (SPHC) is evaluated for performing shock wave simulations by application to 1-D shock tube problems. Results of a shock tube test case with a compression ratio of 10 are compared against a Riemann shock tube problem and theoretical predictions of shock tube behavior to validate the SPH code. A Lagrangian hydrodynamic code is validated in a similar fashion. The resolution capabilities of both codes are compared using 100, 200 and 500 particles for SPHC and 100, 400 and 800 cells for the Lagrangian code. The SPH code exhibits a sharp spike in density at the …

Go to article

An Improved Scheduling Algorithm For Eglin Afb Test Ranges, Jeffrey S. Antes Mar 1992

An Improved Scheduling Algorithm For Eglin Afb Test Ranges, Jeffrey S. Antes

Theses and Dissertations

This research develops an algorithm that integrates into an existing computerized scheduling system to improve the mission scheduling function for Eglin AFB test ranges. The primary objective of this research was to design an improved computerized scheduling aid. The measure of performance for this approach is the number of missions scheduled using this aid as compared to current Eglin capabilities. Constructive heuristics are used in the algorithm to schedule missions according to critical resource groups while ensuring mission priority is not violated. The success of this new interactive scheduling algorithm is measured against a schedule produced by the current computer …

Go to article

Boolean Reasoning And Informed Search In The Minimization Of Logic Circuits, James J. Kainec Mar 1992

Boolean Reasoning And Informed Search In The Minimization Of Logic Circuits, James J. Kainec

Theses and Dissertations

The minimization of logic circuits has been an important area of research for more than a half century. The approaches taken in this field, however, have for the most part been ad hoc. Boolean techniques have been employed to manipulate formulas, but not to perform symbolic reasoning. Boolean equations are employed principally as icons; they are never solved. The first objective of this dissertation is to apply Boolean reasoning systematically and uniformly to the minimization problem. Boolean reasoning entails the reduction of systems of Boolean equations to a single equation; the single equation is an abstraction, independent of the form …

Go to article

Experimental Feedback Of Fractional Order States Of A Lightly Damped Structure, Robert C. Mccall Mar 1992

Experimental Feedback Of Fractional Order States Of A Lightly Damped Structure, Robert C. Mccall

Theses and Dissertations

The purpose of this study was to investigate the effectiveness of using fractional order time derivatives of position feedback signals in the active control of vibration. To that end, circuitry was built and evaluated that finds the half order derivative of an input signal. The magnitude responses of the fractional derivative circuits is very good, but there are large phase shifts present that may degrade the performance of the controllers. Two methods of incorporating the fractional derivative signals into the controller were examined. One method involved developing a similarity transformation that transforms an integer order state controller into an equivalent …

Go to article

An Examination Of Hypercube Implementations Of Genetic Algorithms, Andrew Dymek Mar 1992

An Examination Of Hypercube Implementations Of Genetic Algorithms, Andrew Dymek

Theses and Dissertations

Genetic algorithms are stochastic search algorithms which model natural adaptive systems. In support of the development of a genetic search package for AFIT's iPSC/2 Hypercube, this study focused on two problem areas associated with hypercube implementations. Premature convergence occurs when the population becomes dominated by locally optimal, but globally inferior, solutions. Based on an examination of past hypercube implementations, the selection and communication strategies were hypothesized as causes of premature convergence. Experiments to test these hypotheses were conducted on Rosenbrock's saddle, a function often associated with premature convergence. Communication of best solutions led to premature convergence in small population sizes, …

Go to article

Development Of A Flight Information System Using The Structured Method, Yeong-Lae Kwak Mar 1992

Development Of A Flight Information System Using The Structured Method, Yeong-Lae Kwak

Theses and Dissertations

This thesis documents the development of a database system for the Flight Information System (FIS) of the Korean Air Force. The scope of the FIS is too large to be covered by this thesis. Thus, this thesis covers only the core part of the FIS due to the limitation of time and man-power. This thesis uses the structured method. Structured analysis and structured design techniques are mainly used two techniques. This thesis focused not only the development of the FIS but also the application of the software development method, the structured method, and its tools such as DFD, DD, ERD, …

Go to article

Satool Ii: An IdefO Case Workbench Using Ada And The X Window System, Betty Topp Mar 1992

Satool Ii: An IdefO Case Workbench Using Ada And The X Window System, Betty Topp

Theses and Dissertations

The objective of this research effort is to perform an object oriented analysis, design and implementation of the graphical user interface (GUI) for the SATool II system. SATool II is a computer Assisted Software Engineering (CASE) workbench developed using Ada and the X Window system. It is designed to serve as an IDEFo graphical project editor and data dictionary editor. IDEF0 is the ICAM Definition Method Zero graphical notation language adopted by the Air Force to produce a function model of a manufacturing system or environment. The Air Force Institute of Technology is conducting on-going research in the use …

Go to article

Implementation And Analysis Of Np-Complete Algorithms On A Distributed Memory Computer, Joel S. Garmon Mar 1992

Implementation And Analysis Of Np-Complete Algorithms On A Distributed Memory Computer, Joel S. Garmon

Theses and Dissertations

The purpose of this research is to explore methods used to parallelize NP-complete problems and the degree of improvement that can be realized using different methods of load balancing. A serial and four parallel A* branch and bound algorithms were implemented and executed on an Intel iPSC/2 hypercube computer. One parallel algorithm used a global, or centralized, list to store unfinished work and the other three parallel algorithms used a distributed list to store unfinished work locally on each processor. the three distributed list algorithms are: without load balancing, with load balancing, and with load balancing and work distribution. The …

Go to article

First Prev Next Last