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Frequency Domain Speech Coding, Shane Switzer Dec 1991

Frequency Domain Speech Coding, Shane Switzer

Theses and Dissertations

The major goal of this research was to investigate speech coding techniques in an attempt to achieve high quality speech transmittable at 4800 bits per second. The approach taken to achieve this goal was to code the frequency domain representation of speech. Speech was represented by a sparse set of frequency components. Four frequency selections schemes were implemented, and the resulting frequency coefficients (magnitude and phase) were coded in an efficient manner for transmission. Specific techniques involved in the speech coder included: (1) a recurrent neural architecture to make a periodic/noiselike decision, (2) the use of variable length windows for …

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Requirements Analysis For A Hardware, Discrete-Event, Simulation Engine Accelerator, Paul J. Taylor Jr. Dec 1991

Requirements Analysis For A Hardware, Discrete-Event, Simulation Engine Accelerator, Paul J. Taylor Jr.

Theses and Dissertations

An analysis of a general Discrete Event Simulation (DES), executing on the distributed architecture of an eight mode Intel PSC/2 hypercube, was performed. The most time consuming portions of the general DES algorithm were determined to be the functions associated with message passing of required simulation data between processing nodes of the hypercube architecture. A behavioral description, using the IEEE standard VHSIC Hardware Description and Design Language (VHDL), for a general DES hardware accelerator is presented. The behavioral description specifies the operational requirements for a DES coprocessor to augment the hypercube's execution of DES simulations. The DES coprocessor design implements …

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Implementation Of An Object-Oriented Flight Simulator D.C. Electrical System On A Hypercube Architecture, Guy R. Booth Dec 1991

Implementation Of An Object-Oriented Flight Simulator D.C. Electrical System On A Hypercube Architecture, Guy R. Booth

Theses and Dissertations

The Software Engineering Institute developed an Object-Oriented Paradigm for Flight Simulators based on the concept of mapping the behavior of physical objects from an aircraft into an object-oriented software architecture. This mapping is a semi-formal method that maps objects to a hierarchy that has three logical layers: objects, systems, and executives. The paradigm was developed with the idea of implementing the derived simulation design on a parallel or distributed computer architecture, but no explicity design features are provided for implementing the design on a parallel computer. This research addresses the issue of determining what extensions (if any) are required to …

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Static Pressure Measurements Of A Low Power Arcjet, Kevin P. Talley Dec 1991

Static Pressure Measurements Of A Low Power Arcjet, Kevin P. Talley

Theses and Dissertations

The NASA Lewis 1.2 kilowatt arcjet has been used for a number of performance and lifetime studies. This design was modified to obtain static pressure measurements at several locations along the arcjet nozzle. These measurements were taken at various propellant flow rates over most of the operational envelope of the thruster. Measured static pressure distributions are considerably higher than predicted by ID models and are proportional to the arc power. A simple thermodynamic model is also compared to the data, and is shown to match the slope of the data while overpredicting the pressure.

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Parallel Implementation Of Vhdl Simulations On The Intel Ipsc/2 Hypercube, Ronald C. Comeau Dec 1991

Parallel Implementation Of Vhdl Simulations On The Intel Ipsc/2 Hypercube, Ronald C. Comeau

Theses and Dissertations

VHDL models are executed sequentially in current commercial simulators. As chip designs grow larger and more complex, simulations must run faster. One approach to increasing simulation speed is through parallel processors. This research transforms the behavioral and structural models created by Intermetrics' sequential VHDL simulator into models for parallel execution. The models are simulated on an Intel iPSC/2 hypercube with synchronization of the nodes being achieved by utilizing the Chandy Misra paradigm for discrete-event simulations. Three eight-bit adders, the ripple carry, the carry save, and the carry-lookahead, are each run through the parallel simulator. Simulation time is cut in at …

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An Event Driven State Based Interface For Synthetic Environments, Mark J. Gerken Dec 1991

An Event Driven State Based Interface For Synthetic Environments, Mark J. Gerken

Theses and Dissertations

Previous research at the Air Force Institute of Technology (AFIT) has produced synthetic environments using head mounted displays (HMDs) and hand measurement devices. This thesis is a continuation of AFIT synthetic environment research. Hand measurement data from a VPL DataGlove is combined with hand orientation and translational data to define a set of valid gestures. These gestures form the basis of an input language for class of finite automata known as finite state machines. Using the input symbols from this language, the user may define a finite state machine which associates a stream of input symbols with one or more …

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Analysis Of A Decision Support System For Case Tool Selection And The Specification Of An Ada To Sql Abstract Interface, Tina M. Deangelis Dec 1991

Analysis Of A Decision Support System For Case Tool Selection And The Specification Of An Ada To Sql Abstract Interface, Tina M. Deangelis

Theses and Dissertations

Information overload has long been a problem in the fast moving technical field of software development. Yet quality information is needed to make informed decisions about buying software tools that help in software development. Computer Aided Software Engineering (CASE) tools help to coordinate and control information in large software developments. Many CASE tool purchases, however, are being based on ad hoc tool evaluation and selection methods which depend on biased vendor information. To capture specific knowledge about how to pick a tool for a given software development effort, a historical database that identifies important tool characteristics needed to be maintained …

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Design And Implementation Of A Graphical User Interface And Database Management System For The Saber Wargame, Andrew M. Horton Dec 1991

Design And Implementation Of A Graphical User Interface And Database Management System For The Saber Wargame, Andrew M. Horton

Theses and Dissertations

Saber is a theater level, multi-sided, airpower employment computerized wargame that can be programmed to simulate any combat scenario. The model simulates theater level combat between air and land forces, and takes into account the effects of logistics, resupply, and both theater nuclear and chemical warfare. The major objective of the Saber model is to provide a suitable educational platform to allow users to apply basic, tactical employment concepts to multiple combat units, each having a specialized mission, and incorporating every branch of the armed services. This thesis documents a graphical user interface and data management system that has been …

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An Animated Graphical Postprocessor For The Saber Wargame, Gary W. Klabunde Dec 1991

An Animated Graphical Postprocessor For The Saber Wargame, Gary W. Klabunde

Theses and Dissertations

One of the most cost effective ways to learn and home the skills necessary to conduct and win a war is through the use of realistic computer simulations of conflict, or wargames. The Saber wargame was developed for just this purpose. Saber is a multisided, theater-level simulation developed by the Air Force Institute of Technology for the Air Force Wargaming Center. It models conventional, nuclear, and chemical warfare between aggregated air and ground forces. To aid in the realism, the effects of logistics, satellites, weather, and intelligence are represented. Saber provides an avenue for senior level joint service officers to …

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Enhanced Animation Of Parallel Algorithms, Michael D. Lack Dec 1991

Enhanced Animation Of Parallel Algorithms, Michael D. Lack

Theses and Dissertations

Algorithm animation is a visualization method used to enhance understanding of the functioning of an algorithm or program. Visualization is used for many purposes, including education, algorithm research, performance analysis, and program debugging. This research, which follows from previous work, examines algorithm animation requirements for the various visualization purposes and extends the capabilities of an existing facilities, the AFIT algorithm Animation Research Facility (AAARF). The structure of AAARF is summarised and its visualization capabilities presented, analysed and compared with other similar packages. This research focuses on the parallel data requirements of the AAARF users, and the meaningful display of large …

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Graph-Based Visualization Of Formal Specification And Domain Specific Languages, Randel K. Langloss Dec 1991

Graph-Based Visualization Of Formal Specification And Domain Specific Languages, Randel K. Langloss

Theses and Dissertations

This research develops and implements Visual Refine, a graph-based visualization system, for the Refine wide-spectrum formal specification language and environment developed and marketed by Reasoning Systems, Inc. Refine specifications are represented in the Refine object base as abstract syntax trees (AST). Using these AST representations, one-to-one mappings are defined between nodes of the AST and the graphical icons of Visual Refine. Visual Refine uses these mappings to implement a set of formal transformations. Each transformation is encapsulated within a Refine rule, and this set of rules form the Visual Refine transformation system. The Visual Refine transformation system, in conjunction with …

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A Comparative Analysis Of Computer End-User Support In The Air Force And Civilian Organizations, Maureen C. Casey, Douglas A. Kveene Dec 1991

A Comparative Analysis Of Computer End-User Support In The Air Force And Civilian Organizations, Maureen C. Casey, Douglas A. Kveene

Theses and Dissertations

This study compared end-user computing support provided by the Air Force to support provided by civilian organizations with information centers and those without. Factors measured included the end user's demographics, applications used, the effect of computing on perceived confidence, productivity, quality and quantity of output, the importance of various types of support, and satisfaction with the support received from different sources. A survey was administered to 450 Air Force and 265 civilian end users; 416 were returned (response rate of 58.18%). Although there were significant demographic differences between end users, there were no differences in types of support required. Training, …

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A Study Of The Adoption And Effectiveness Of Electronic Mail At The Air Force Institute Of Technology, Douglas D. White Dec 1991

A Study Of The Adoption And Effectiveness Of Electronic Mail At The Air Force Institute Of Technology, Douglas D. White

Theses and Dissertations

This research investigated the relationship between the adoption and effectiveness of electronic mail at the Air Force institute of Technology's School of Systems and Logistics (LS). In this research, theories concerning innovation adoption and measurement of system effectiveness are discussed. Survey instruments from both areas were selected, tested, and used to collect data from the LS faculty and staff. Correlation analysis was performed using the data collected. Findings indicate a correlation does exist between the adoption of electronic mail and the effectiveness surrogate measurement, user satisfaction. There was a significantly strong negative correlation between electronic mail complexity and user satisfaction.

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A Delphi Forecast Of 1996 Roles: Air Force Institute Of Technology Information Resource Management Graduates Assigned To Base Level, David O. Block Dec 1991

A Delphi Forecast Of 1996 Roles: Air Force Institute Of Technology Information Resource Management Graduates Assigned To Base Level, David O. Block

Theses and Dissertations

Graduates of the Air Force Institute of Technology's Information Resource Management master's degree program who are subsequently assigned to base-level positions believe their IRM expertise is wasted in base administration roles that preclude the use of their up-to-date technical educations in managing automated information resources. This research forecasts the role AFIT IRM graduates assigned to base-level positions will need to fill by the year 1996. The research further determined what changes are necessary to resolve the perceived differences between current and forecast roles for these graduates. The Delphi survey method of forecasting was selected as an effective method of discovering …

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An Analysis Of The Information Requirements Of Conus Based Deputy Commanders For Maintenance, Daniel J. Green Dec 1991

An Analysis Of The Information Requirements Of Conus Based Deputy Commanders For Maintenance, Daniel J. Green

Theses and Dissertations

The purpose of this research was to identify the information requirements of Air Force Deputy Commanders for Maintenance. It had three basic objectives: (1) identify the critical success factors that they monitor on a continuous basis, (2) identify similarities in those requirements for all DGMs and across major commands, and (3) determine if the application of information technology would enhance their decision making. Surveys were sent to all CONUS based Deputy Commanders for Maintenance. The study found that there were nine critical success factors that were used by a majority of all respondents. In addition, nine command-specific critical success factors …

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Possible Application Of Quality Function Deployment In Software Systems Development In The United States Air Force, Craig R. Lamb Dec 1991

Possible Application Of Quality Function Deployment In Software Systems Development In The United States Air Force, Craig R. Lamb

Theses and Dissertations

The objectives of the thesis were to determine whether the methods of Quality Function Deployment (QFD) could be used in the software development environment within the USAF, and whether or not this area should be researched further. The research was limited to the requirements analysis and definition phase. The different areas of study included a brief review of the structured analysis methodology, a detailed review of the QFD models currently being used in the product industries, a review of how QFD fits into the software development cycle, and specific software modifications to the QFD methodology. A review of some applications …

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A Comparative Study Of Numerical Versus Analytical Waverider Solutions, Gregory O. Stecklein Dec 1991

A Comparative Study Of Numerical Versus Analytical Waverider Solutions, Gregory O. Stecklein

Theses and Dissertations

The WL/FIMM explicit, Roe flux-splitting Euler algorithm is applied to the inviscid hypersonic flow over a parabolic-top waverider configuration optimized for Mach 10 at zero degrees angle of attack. An on-design grid refinement study is conducted to determine the asymptotic nature of the optimized flight parameter L/D. A parametric study of off-design conditions is conducted to determine flow perturbation effects on HSDT waverider theory. A validation of the Euler code is conducted through a comparison of the numerical data to analytical results derived by Rasmussen. The grid refinement study shows little effect on the inviscid calculation of the optimized parameter …

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Object-Oriented Analysis And Design Of The Saber Wargame, Christine M. Sherry Dec 1991

Object-Oriented Analysis And Design Of The Saber Wargame, Christine M. Sherry

Theses and Dissertations

This thesis presents an object-oriented analysis and design of Saber, a theater-level computerized wargame, for the Air Force Wargaming Center, Maxwell AFB, Alabama. The analysis and design is based on a recently developed conceptual model, and existing land battle, and additional research. This thesis also begins the implementation process. The design was accomplished using an iterative, five step design process. Objects and operations were chosen and then encapsulated in Ada packages. This thesis also makes necessary changes to the land battle as described by the conceptual model and as the result of additional research. Sound software engineering principles were used …

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Function Prediction Using Recurrent Neural Networks, Randall L. Lindsey Dec 1991

Function Prediction Using Recurrent Neural Networks, Randall L. Lindsey

Theses and Dissertations

A fully recurrent neural network was applied to the function prediction problem. The real-time recurrent learning (RTRL) algorithm was modified and tested for use as a viable function predictor. The modification gave the algorithm a variable learning rate and a linear/sigmoidal output selection. Verifying the networks ability to temporally learn both the classic exclusive-OR (XOR) problem and the internal state problem, the network was then used to simulate the frequency response of a second order IIR lowpass Butterworth filter. The recurrent network was then applied to two problems: head position tracking, and voice date reconstruction. The accuracy at which the …

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Verification And Validation Of The Comprehensive Operational Support Evaluation Model For Space, Lawrence A. Cooper Dec 1991

Verification And Validation Of The Comprehensive Operational Support Evaluation Model For Space, Lawrence A. Cooper

Theses and Dissertations

This study details the verification and validation (V and V) of the Comprehensive Operational Support Evaluation Model for Space (COSEMS). COSEMS is an Ada-based simulation which models spacecraft constellation support concepts such as support from the ground and on-orbit support. While the model is intended for use in analyzing Strategic Defense System concepts, it can easily evaluate non-military satellite constellations. The V&V was confined to a subset of the over 200 subprograms which comprise COSEMS. This subset covered random number generation, reliability, orbital mechanics, and mission planning functions. The study used traces and comparison to other models to perform the …

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Swatter (Space-Based Weapons Against Tactical Terrestrial-Based Resources): A Design For Integrating Space Into A Theater Level Wargame, Duane R. Cozadd Dec 1991

Swatter (Space-Based Weapons Against Tactical Terrestrial-Based Resources): A Design For Integrating Space Into A Theater Level Wargame, Duane R. Cozadd

Theses and Dissertations

This thesis provides the foundation to expand the newly developed theater level computerized wargame, SABER, at the Air Force Wargaming Center, Maxwell AFB, Alabama to include space conflict at the theater level of simulation. Building upon the recently completed SABER, this thesis effort expands the conceptual framework of the model by integrating the dynamics of space warfare into the current theater level model. This expansion forms a new game called SWATTER. This thesis adds the space units required to integrate the land and air battles with the possible interactions from space. This thesis expands the stochastic attrition processes to include …

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Documentation Requirements For Software Maintenance, Timothy S. Mcarthur Dec 1991

Documentation Requirements For Software Maintenance, Timothy S. Mcarthur

Theses and Dissertations

This study investigated the requirement for documentation during the maintenance phase of the software life cycle. Without proper documentation, maintenance personnel are not able to effectively understand the design of a software system and spend many hours performing design recovery before any type of maintenance can be performed. A review of existing information showed a wide range of opinion among the experts in the field of software maintenance and was not conclusive. A survey of Air Force software maintenance personnel was then conducted to determine the need, availability, and tailoring results of the documents listed on DOD-STD 2167A. The analysis …

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A Time-Dependent Adaptive Filter For Cochannel Interference Reduction, Matthew H. Foster Dec 1991

A Time-Dependent Adaptive Filter For Cochannel Interference Reduction, Matthew H. Foster

Theses and Dissertations

This thesis presents a Time Dependent Adaptive Filter (TDAF) which exploits the cyclostationarity of digitally modulated communications signals and seeks to improve the Signal to Interference Ratio (SIR) and Signal to Noise Ratio (SNR) of such signals. The TDAF is embedded in a computer simulation of a simple communication system consisting of a data source, data formatter, pulse shaping filter, BPSK modulator, and demodulator. In the simulation the TDAF and a Time Independent Adaptive Filter (TIAF) attempt to extract the Signal of Interest (SOI) from noise or interference. the criteria of Mean Squared Error (MSE) is used as the primary …

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Infrared Target Recognition, Brian D. Singstock Dec 1991

Infrared Target Recognition, Brian D. Singstock

Theses and Dissertations

In this thesis, three approaches were used for Automatic Target Recognition (ATR). These approaches were shape, moment and Fourier generated features, Karhunen-Loeve transform (KLT) generated features and Discrete Cosine Transform (DCT) generated features. The KLT approach was modelled after the face recognition research by Suarez, AFIT, and Turk and Pentland, MIT. A KLT is taken of a reduced covariance matrix, composed all three classes of targets, and the resulting eigenimages are used to reconstruct the original images. The reconstruction coefficients for each original image are found by taking the dot product of the original image with each eigenimage. These reconstruction …

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Music As Communication: A Rhetorical Perspective Based On Susanne Langer's Theory Of Aesthetic Symbolism, Deanna D. Sellnow Dec 1991

Music As Communication: A Rhetorical Perspective Based On Susanne Langer's Theory Of Aesthetic Symbolism, Deanna D. Sellnow

Theses and Dissertations

The purpose of this dissertation is to create a rhetorical perspective by which to understand and analyze music as aesthetic communication. Specifically, this study extends Susanne Langer's theory of aesthetic symbolism as it relates to music as a mode of communication. Once the rhetorical perspective for analyzing music as communication has been depicted, the perspective is operationalized to analyze music from two contemporary social movements in the United States. The music analyzed in this dissertation comes from the Neo-Nazi Skinhead movement and the New Age movement. By approaching music as aesthetic communication in this way, the reader is able to …

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The Aicpa And Government Auditing Standards A Comparison, Lori Stacey Nov 1991

The Aicpa And Government Auditing Standards A Comparison, Lori Stacey

Theses and Dissertations

No abstract provided.

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Comparative Analysis Of Guidance Algorithms For The Hyper Velocity Missile And Afti/F-16, Edward G. Rice Nov 1991

Comparative Analysis Of Guidance Algorithms For The Hyper Velocity Missile And Afti/F-16, Edward G. Rice

Theses and Dissertations

This project has provided me with endless intrigue. In considering the problem of guiding a hyper-velocity missile from a moving platform to a moving target, a common perception said it was just another Kalman Filtration design challenge. I began with lofty intentions of running a full up extended Kalman filter simulation but I became enthralled with the limited work available on the physical limitations of basic guidance algorithms. This became the emphasis of this project. The best filter scheme cannot overcome a guidance algorithms physical limitation. Only with an understanding of these limitations can one effectively integrate a guidance scheme …

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Application Of Low Thrust Propulsion Techniques To Satellite Attitude Control Systems, Jeffrey J. Abbott Nov 1991

Application Of Low Thrust Propulsion Techniques To Satellite Attitude Control Systems, Jeffrey J. Abbott

Theses and Dissertations

Equation of motion for a satellite controlled through continuous, low thrust propulsion systems are analyzed through numerical integration techniques. The equations of motion are derived using the Euler Moment Equations. The properties of the satellite model are based upon the Intelsat VII design of communications satellite. A simple rate and error feedback controller is used in providing active attitude control about two and three axes. Perturbation models are created and applied based upon the satellite model. Parameters varied include thrust levels and controller deadband widths. System response times, pointing accuracy, and total impulse required for attitude control are determined as …

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Patterns Of Undermining: American And British Novels Set In Coal-Mining Locales., Julie Ann Maristuen-Rodakowski Oct 1991

Patterns Of Undermining: American And British Novels Set In Coal-Mining Locales., Julie Ann Maristuen-Rodakowski

Theses and Dissertations

This dissertation focuses on twenty novels--ten by men and ten by women--set in coal-mining locales circa 1840 to 1940. It analyzes power relationships and structures of oppression that emerge through the fictional techniques of setting, character, and theme, positing that a paradigm shift is visible in some texts. Hegemonic power relationships and the accompanying oppression of the "less important" entity in male/female, management/labor configurations are evident in many of the novels, but some texts treat the power relationships differently. In these texts, the role of the women and the role of the laborers shift from that of a marginalized Other …

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College Preparatory Courses Offered And Percentages Of Graduating Seniors Attending Postsecondary Education In Selected Minnesota Public Senior High Schools., John Stewart Backes Oct 1991

College Preparatory Courses Offered And Percentages Of Graduating Seniors Attending Postsecondary Education In Selected Minnesota Public Senior High Schools., John Stewart Backes

Theses and Dissertations

This study examined the Minnesota public senior high school curricula (grades 10-12) and determined how many graduating seniors attended postsecondary education after high school. Specific research questions were (1) What percentage of the course offerings available in 1988-89 were college preparatory? (2) What percentage of the courses actually taught were college preparatory? (3) What percentage of the 1988 graduating seniors in Minnesota public schools attended postsecondary education after high school? (4) Did this percentage change during the previous decade?The study included all public school districts in Minnesota that reported 1988-89 Secondary Professional Staff Assignments to the Minnesota State Department of …

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