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Air Force Institute of Technology

Theses and Dissertations

Theses/Dissertations

2003

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Generalized Residual Multiple Model Adaptive Estimation Of Parameters And States, Charles D. Ormsby Oct 2003

Generalized Residual Multiple Model Adaptive Estimation Of Parameters And States, Charles D. Ormsby

Theses and Dissertations

This dissertation develops a modification to the standard Multiple Model Adaptive Estimator (MMAE) which allows the use of a new "generalized residual" in the hypothesis conditional probability calculation. The generalized residual is a linear combination of traditional Kalman filter residuals and "post-fit" Kalman filter residuals which are calculated after measurement incorporation. This modified MMAE is termed a Generalized Residual Multiple Model Adaptive Estimator (GRMMAE). The dissertation provides a derivation of the hypothesis conditional probability formula which the GRMMAE uses to calculate probabilities that each elemental filter in the GRMMAE contains the correct parameter value. Through appropriate choice of a single …

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A Communications Modeling System For Swarm-Based Sensors, Brian A. Kadrovach Sep 2003

A Communications Modeling System For Swarm-Based Sensors, Brian A. Kadrovach

Theses and Dissertations

Today's information age has exploded the amount of data available to decision makers at all levels of the control hierarchy. The miniaturization and proliferation of sensor technology has enabled extensive detection and monitoring and advances in computational capabilities have provided for embedded data analysis and the generation of information from raw data. Additionally, with the miniaturization of mechanical systems it is possible to provide platforms for sensor suites that are capable of mobility and limited autonomy. Swarming or bio-emergent behavior problems, provides a robust scalable mechanism for organizing large numbers of mobile sensor platforms. However, the mobility dynamics of swarm …

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Electron Paramagnetic Resonance Spectroscopy And Hall Effect Studies Of The Effects Of Low Energy Electron Energy On Gallium Nitride (Gan), Kevin D. Greene Sep 2003

Electron Paramagnetic Resonance Spectroscopy And Hall Effect Studies Of The Effects Of Low Energy Electron Energy On Gallium Nitride (Gan), Kevin D. Greene

Theses and Dissertations

The nature of native donors in GaN, types and interactions of radiation-induced defects, and damage creation coefficients for 1.0 MeV electron irradiation have been ascertained by the concerted application of electron paramagnetic resonance spectroscopy and Hall effect measurements to virgin and electron-irradiated GaN epilayers. Samples produced via molecular beam epitaxy and hydride vapor phase epitaxy, both silicon doped and nominally undoped, were subjected to Van de Graff generator produced monoenergtic electron beams with total fluences of 1016- 1018 electrons/cm2. Nitrogen vacancies are rejected as a possible cause of n-type conductivity in nominally undoped GaN due …

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Cooperative Control Simulation Validation Using Applied Probability Theory, Christopher S. Schulz Sep 2003

Cooperative Control Simulation Validation Using Applied Probability Theory, Christopher S. Schulz

Theses and Dissertations

Several research simulations have been created to support development and refinement of teamed autonomous agents using decentralized cooperative control algorithms. Simulation is the necessary tool to evaluate the performance of decentralized cooperative control algorithms, however these simulations lack a method to validate their output. This research presents a method to validate the performance of a decentralized cooperative control simulation environment for an autonomous Wide Area Search Munition (WASM). Rigorous analytical methods for six wide area search and engagement scenarios involving Uniform, Normal, and Poisson distributions of N real targets and M false target objects are formulated to generate expected numbers …

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Controlled-Stress Large-Area Pulsed Laser Deposition Of Yttria Stabilized Zirconia, Paul C. Rounsavall Sep 2003

Controlled-Stress Large-Area Pulsed Laser Deposition Of Yttria Stabilized Zirconia, Paul C. Rounsavall

Theses and Dissertations

The US Air Force has need of parabolic-shaped membrane mirrors for surveillance satellites. The current polymer membrane technology has been unable to overcome shape deformation problems caused by intrinsic stresses from the membrane casting and mounting processes. One proposed solution was to coat the membrane mirrors with a stressed coating to compensate for shape deformations. Thus, the research presented in this dissertation produced controlled-stress large-area pulsed laser deposition (PLD) grown thin films on polymer substrates and investigated optical time-of-flight (TOF) sensor systems and Raman spectroscopy for control for the PLD process with respect to thin film stress. Initially, the PLD-grown …

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Broadening And Shifting Of Atomic Strontium And Diatomic Bismuth Spectral Lines, Jeremy C. Holtgrave May 2003

Broadening And Shifting Of Atomic Strontium And Diatomic Bismuth Spectral Lines, Jeremy C. Holtgrave

Theses and Dissertations

The objective of this research is to study the effects of noble gases on atomic strontium and diatomic bismuth visible transitions, Specifically, this research seeks to determine if the line broadening and, in the case of atomic strontium, line shifting rates of these transitions in the presence of noble gases depend on the total angular momenta of the energy states involved. It has been known for more than a century that atomic and molecular spectral lines are broadened and shifted by perturbing species. While a considerable body of theoretical work has been accomplished on this topic over the years, only …

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Classification Of Radar Targets Using Invariant Features, Gregory J. Meyer Apr 2003

Classification Of Radar Targets Using Invariant Features, Gregory J. Meyer

Theses and Dissertations

Automatic target recognition ATR using radar commonly relies on modeling a target as a collection of point scattering centers, Features extracted from these scattering centers for input to a target classifier may be constructed that are invariant to translation and rotation, i.e., they are independent of the position and aspect angle of the target in the radar scene. Here an iterative approach for building effective scattering center models is developed, and the shape space of these models is investigated. Experimental results are obtained for three-dimensional scattering centers compressed to nineteen-dimensional feature sets, each consisting of the singular values of the …

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Electrical Activation Studies Of Silicon Implanted Alx Gal-X N And Coimplanted Gan, Elizabeth A. Chitwood Mar 2003

Electrical Activation Studies Of Silicon Implanted Alx Gal-X N And Coimplanted Gan, Elizabeth A. Chitwood

Theses and Dissertations

A comprehensive study of the electrical activation of silicon implanted AlxGa1-xN was performed as a function ion dose, anneal temperature, and aluminum mole fraction, Also, GaN coimplanted with silicon and nitrogen was investigated. Room temperature Hall effect measurements were used to determine carrier concentration and mobility. All the samples had a 500 Å encapsulant of AlN, and were implanted at room temperature with 200 keV silicon ions at doses ranging from 1x1013 to 1x1015 /sq cm. The GaN was also implanted with nitrogen under the same conditions in doses of 9x1012 to 9x10 …

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Luminescence Studies Of Ion-Implanted Gallium Nitride And Aluminum Gallium Nitride, Erin N. Claunch Mar 2003

Luminescence Studies Of Ion-Implanted Gallium Nitride And Aluminum Gallium Nitride, Erin N. Claunch

Theses and Dissertations

Recently, research on the wide bandgap semiconductors such as GaN and Al(x)Ga(1-x)N became very popular for their applications on various devices. Therefore comprehensive and systematic luminescence studies of Si implanted AlxGa1-xN, Mg doped GaN, and Si+N implanted GaN grown on sapphire substrates by molecular beam epitaxial method have been made as a function of ion dose and anneal temperature.

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An Analysis Of The Federal Acquisition Streamlining Act And The Clinger-Cohen Act And Their Effect On Cost Overruns In Department Of Defense Contracts, Andrew K. Mosier Mar 2003

An Analysis Of The Federal Acquisition Streamlining Act And The Clinger-Cohen Act And Their Effect On Cost Overruns In Department Of Defense Contracts, Andrew K. Mosier

Theses and Dissertations

This thesis examines the impact of the Federal Acquisition Streamlining Act (FASA) of 1994 and the Clinger-Cohen Act on cost overruns in Department of Defense (DoD) contracts. Many officials believe that we must change the way we do business to meet the new post-Cold War national security challenges Changing the way we do business means reforming the acquisition process to deliver weapons systems faster and cheaper. The FASA and the Clinger-Cohen Act made more changes to the acquisition process than any other policy had in the ten years preceding. This research effort studied 220 contracts completed between December 31, 1993 …

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Characterization Of Chlorinated Solvent Degradation In A Constructed Wetland, Nathan D. Clemmer Mar 2003

Characterization Of Chlorinated Solvent Degradation In A Constructed Wetland, Nathan D. Clemmer

Theses and Dissertations

Widespread chlorinated ethene contamination of aquifers coupled with high costs of current treatment technologies demand innovative remediation solutions. Wetlands, maintaining anaerobic and aerobic zones promoting the complete degradation of chlorinated ethenes such as Tetrachloroethylene (PCE), could be the answer. This thesis characterized the chlorinated solvent contamination levels in three strata of an upward flow constructed wetland. Analysis of samples was accomplished by purge-and-trap gas chromatography. Water quality parameters, Dissolved Oxygen (DO), Oxidation Reduction Potential (ORP), pH, Conductivity, and Temperature, were also measured in monitoring wells with a water monitoring sonde. After removing data outliers caused by short-circuiting flow, PCE concentrations …

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Transient Analysis And Applications Of Markov Reward Processes, Jeffrey A. Sipe Mar 2003

Transient Analysis And Applications Of Markov Reward Processes, Jeffrey A. Sipe

Theses and Dissertations

In this thesis, the problem of computing the cumulative distribution function (cdf) of the random time required for a system to first reach a specified reward threshold when the rate at which the reward accrues is controlled by a continuous time stochastic process is considered. This random time is a type of first passage time for the cumulative reward process. The major contribution of this work is a simplified, analytical expression for the Laplace-Stieltjes Transform of the cdf in one dimension rather than two. The result is obtained using two techniques: i) by converting an existing partial differential equation to …

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Spacecraft Charging At Geosynchronous Altitudes: Current Balance And Critical Temperature In A Non-Maxwellian Plasma, Jose T. Harris Mar 2003

Spacecraft Charging At Geosynchronous Altitudes: Current Balance And Critical Temperature In A Non-Maxwellian Plasma, Jose T. Harris

Theses and Dissertations

Spacecraft charging threatens to disable spacecraft components and adversely impact any satellite function. Electrostatic charge, and especially discharge, can hinder the proper operation of, or destroy, spacecraft components, thereby rendering the spacecraft ineffective or inoperative. The level of charging is dependent on the particle energy (speed) distribution. Current spacecraft design and material provide limited protection against the dangers of electrostatic discharge, and active measures such as beam emission are also employed.

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An Analysis Of Microbial Contamination In Military Aviation Fuel Systems, Harold W. Graef Mar 2003

An Analysis Of Microbial Contamination In Military Aviation Fuel Systems, Harold W. Graef

Theses and Dissertations

Military aviation fuel systems can be an ideal environment for microorganisms. Microbial growth in hydrocarbon fuel systems arises because of the impracticality of keeping fuel tanks sterile and the inevitable presence of water from condensation. Microbial contaminants in aviation fuel systems are a concern because of their potential to degrade the fuel, accelerate tank corrosion, and threaten flight safety. This research addresses the concern of using more environmentally friendly Fuel System Icing Inhibitors (FSII), which are also biocidal. Are significant levels of microorganisms growing in military aviation fuel systems, and if so, are there any common variables? Forty aviation fuel …

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Analysis Of The Theoretical Relationships Between Work Exhaustion, Job Satisfaction, And Turnover Intention Of Air Force Information Systems Managers, Alfred D. Ray Mar 2003

Analysis Of The Theoretical Relationships Between Work Exhaustion, Job Satisfaction, And Turnover Intention Of Air Force Information Systems Managers, Alfred D. Ray

Theses and Dissertations

The use of information technology has increased exponentially over the last two decades (Cohen and Burton, 2001), Accordingly, the ability of organizations to retain their information systems staff has been a critical factor in the effort to achieve strategic goals (Moore, 2002), When IS professionals leave an organization, not only is the number of them available for assignment to projects depleted, the professionals themselves often take specialized skills, tacit knowledge, and understanding of specific business operations and information systems with them (Agarwal and Ferratt, 2002), Chief Executives have become increasingly interested in issues related to the recruitment, development, and retention …

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Experimental Results For A High Swirl, Ultra Compact Combustor For Gas Turbine Engines, Ryan J. Quaale Mar 2003

Experimental Results For A High Swirl, Ultra Compact Combustor For Gas Turbine Engines, Ryan J. Quaale

Theses and Dissertations

Laser Doppler Velocimeter (LDV) experiments have been conducted within the cavity of an atmospheric pressure, small scale, Ultra Compact Combustor (UCC). The UCC uses highly swirled flow in a cavity around the outside periphery of the combustor to generate high centripetal acceleration in the fluid. This enhances mixing and leads to a very short axial flame length. Additionally, due to the circumferential velocity, much of the residence time required by the flame is provided by the circumference of the engine rather than axial length as in conventional combustors.

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Phasing A Dual Optical Path System Using An Optical Fiber As A Phase Conjugate Mirror, Shawn M. Willis Mar 2003

Phasing A Dual Optical Path System Using An Optical Fiber As A Phase Conjugate Mirror, Shawn M. Willis

Theses and Dissertations

Phase conjugation properties of stimulated Brillouin scattering (SBS) in a short multimode fiber have been investigated with an eye towards its application for a multi-channel double pass master oscillator power amplifier (MOPA) system. In particular, properties of the SBS beam to compensate for the axial and transverse phase distortion between individual channels in a multi-channel amplifier system were studied. Two optical paths were created by covering half of the laser beam with a microscope slide, and also by spatially splitting the wavefronts with a 4 prism set-up. The Stokes beams that traversed the same optical paths as the pump beams …

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Estimating Procurement Cost Growth Using Logistic And Multiple Regression, Gary W. Moore Mar 2003

Estimating Procurement Cost Growth Using Logistic And Multiple Regression, Gary W. Moore

Theses and Dissertations

Cost Growth in Department of Defense (DoD) major systems has been an ongoing problems for more than 30 years. Previous research has demonstrated the use of two-step logistic and multiple regression methodology to predicting cost growth produces desirable results traditional single-step regression. This research effort validates, and further explores the use of a two-step procedure for assessing DoD major weapon system cost growth using historical data. We compile programmatic data from the Selected Acquisition Reports (SARs) between 1990 and 2001 for programs covering all defense departments. Our analysis concentrates on cost growth in procurement dollar accounts for the Engineering and …

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A Comparative Analysis Of The Cost Estimating Error Risk Associated With Fly Away Costs Vs Individual Components Of Aircraft, Jonathan D. Ritschel Mar 2003

A Comparative Analysis Of The Cost Estimating Error Risk Associated With Fly Away Costs Vs Individual Components Of Aircraft, Jonathan D. Ritschel

Theses and Dissertations

A shrinking workforce, unstable budgets, and rapidly changing objectives under stricter time constraints characterize today's cost analysis and acquisition environment. In concert with this environment, cost analyst positions have rapidly decreased as demonstrated by Aeronautical Systems Centers 54% decline in total authorized slots from 1992 to 2001. The question is how to deal with this more with less' mentality. The purpose of this research is to investigate and measure the risks associated with taking a macro versus micro approach to aircraft cost estimation. By analyzing the fidelity of a cost estimate developed at the flyaway cost level versus a cost …

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Combat Air Forces Campaign Level Modernization Planning-A Study In Group Decision Making, Ian L. Walker Mar 2003

Combat Air Forces Campaign Level Modernization Planning-A Study In Group Decision Making, Ian L. Walker

Theses and Dissertations

Modernization is a critical component of the current transformation effort within the Department of Defense (DoD) Effective and efficient modernization planning will provide for the improved allocation of limited funding. The Air Force currently conducts capabilities based modernization planning to identify shortfalls. Air Combat Command (ACC) utilizes multi-objective decision analysis (MODA) techniques to support the modernization planning process (MPP). A MODA model has been created to identify and quantify capability shortfalls across a diverse range of mission areas. Groups of subject matter experts are utilized to provide model inputs improving the usefulness and credibility of the model. The intent of …

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Implementing An Information Retrieval And Visualization Framework For Heterogeneous Data Types, Andrew J. Kowalchuk Mar 2003

Implementing An Information Retrieval And Visualization Framework For Heterogeneous Data Types, Andrew J. Kowalchuk

Theses and Dissertations

In today's information focused world, there is no lack of entities focused on information gathering. However, there is still a widespread epidemic of information starvation in the Department of Defense (DoD). This starvation is attributed to the lack of interoperability between information gatherers and information consumers. To alleviate this problem, the DoD has put forth a vision of a Joint Battlespace Infosphere (JBI). This research proposes a framework for sharing and finding resources in a JBI. The framework uses an extensible metadata specification, agent technology, and the Control of Agent Based Systems (CoABS). It provides several tools for publication and …

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Using Sequence Analysis To Perform Application-Based Anomaly Detection Within An Artificial Immune System Framework, Larissa A. O'Brien Mar 2003

Using Sequence Analysis To Perform Application-Based Anomaly Detection Within An Artificial Immune System Framework, Larissa A. O'Brien

Theses and Dissertations

The Air Force and other Department of Defense (DoD) computer systems typically rely on traditional signature-based network IDSs to detect various types of attempted or successful attacks. Signature-based methods are limited to detecting known attacks or similar variants; anomaly-based systems, by contrast, alert on behaviors previously unseen. The development of an effective anomaly-detecting, application based IDS would increase the Air Force's ability to ward off attacks that are not detected by signature-based network IDSs, thus strengthening the layered defenses necessary to acquire and maintain safe, secure communication capability. This system follows the Artificial Immune System (AIS) framework, which relies on …

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Adjusting Sensing Range To Maximize Throughput On Ad-Hoc Multi-Hop Wireless Networks, Christopher K. Roberts Mar 2003

Adjusting Sensing Range To Maximize Throughput On Ad-Hoc Multi-Hop Wireless Networks, Christopher K. Roberts

Theses and Dissertations

The use of ad-hoc wireless networks is becoming common within the United States Air Force. Such networks are able to be implemented where traditional wired networks are either impractical or too expensive. As the miniaturization of communication devices continues, it is becoming increasingly common for mobile devices to communicate directly with each other, eliminating the need for center access points. Such a network is referred to as a multi-hop ad-hoc network, or simply a multi-hop network. Most multi-hop network protocols use some form of carrier sensing to determine if the wireless channel is in use. A large sensing range can …

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Groundwater Flow Through A Constructed Treatment Wetland, Jack A. Blalock Mar 2003

Groundwater Flow Through A Constructed Treatment Wetland, Jack A. Blalock

Theses and Dissertations

This study is an analysis of the flow of water through a constructed treatment wetland at Wright-Patterson AFB, OH. The purpose of the treatment wetland is to biodegrade perchioroethylene, which is present in the groundwater as a contaminant. Contaminated water enters the bottom of the wetland and flows upward, exiting the wetland from a weir at one end. The wetland is designed for water to move vertically through the soil layers composing the wetland. The main purpose of this study is to characterize the water flow through the different layers of soil in the wetland. In this study, hydraulic parameters …

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A Life Cycle Assessment And Economic Analysis Of Wind Turbines Using Monte Carlo Simulation, Edward J. Liberman Mar 2003

A Life Cycle Assessment And Economic Analysis Of Wind Turbines Using Monte Carlo Simulation, Edward J. Liberman

Theses and Dissertations

The United States depends heavily on nonrenewable fossil fuels to generate electricity. Using renewable energy sources, such as wind, could reduce air emissions and fossil fuel dependency. Previous studies have examined the life cycle costs and environmental impacts of using wind to generate electricity, but results have varied due to inconsistent modeling assumptions. This research uses Monte Carlo simulation to conduct an economic payback analysis and life cycle assessment of 11 modern, utility-scale wind turbines. Hourly meteorological data was used to evaluate 239 U.S. locations. For each location, the wind turbine with the shortest median payback period was assumed to …

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Development And Simulation Of A Pseudolite-Based Flight Reference System, Terry J. Bouska Mar 2003

Development And Simulation Of A Pseudolite-Based Flight Reference System, Terry J. Bouska

Theses and Dissertations

Current flight reference systems are vulnerable to GPS jamming and also lack the accuracy required to test new systems. Pseudolites can augment flight reference systems by improving accuracy, especially in the presence of GPS jamming. This thesis evaluates a pseudolite-based flight reference system which applies and adapts carrier-phase differential GPS techniques. The algorithm developed in this thesis utilizes an extended Kalman filter along with carrier-phase ambiguity resolution techniques. A simulation of the pseudolite-based positioning system realistically models measurement noise, multipath, pseudolite position errors, and tropospheric delay. A comparative evaluation of the algorithms performance for single and widelane frequency measurements is …

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Ins Aiding Using Passive, Bearings-Only Measurements Of An Unknown Stationary Ground Object, Alec E. Porter Mar 2003

Ins Aiding Using Passive, Bearings-Only Measurements Of An Unknown Stationary Ground Object, Alec E. Porter

Theses and Dissertations

The theory for Inertial Navigation System (INS) aiding using passive, bearings only measurements of an unknown stationary ground object, in the vein of optical flow measurement, is developed. Stand-alone bearings-only measurements over time of an unknown, but stationary, ground object are shown to yield estimates of the aircraft’s aerodynamic angles, viz., the angle of attack and sideslip angle. Two new equations containing the aircraft’s angular navigation variables ψ, θ, φ, γ, H, and the aerodynamic angles are derived. This allows an update of the aircraft’s attitude, thus making INS aiding using passive, bearings-only measurements possible. Moreover, the use of stadiametry, …

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Fast Compression Of Imagery With High Frequency Content, D. Scott Anderson Mar 2003

Fast Compression Of Imagery With High Frequency Content, D. Scott Anderson

Theses and Dissertations

Image compression is an active area due to the many applications involving electronic media. Much research has been focused on image quality versus bit rate and/or algorithm speed. Here, we seek an effective image coder with a weighted constraint on speed. However, the compression must not taint the quality of impulsive features on the image. Moreover, the camera is operated in a mode that creates a dominant fixed pattern noise across the image array, degrading visual quality and disrupting compression performance. We propose a method that efficiently compresses such an image. We begin by characterizing and removing the fixed pattern …

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The Effect Of Interactivity And Instructional Exposure On Learning Effectiveness And Knowledge Retention: A Comparative Study Of Two U.S. Air Force Computer-Based Training (Cbt) Courses For Network User Licensing, Matthew J. Imperial Mar 2003

The Effect Of Interactivity And Instructional Exposure On Learning Effectiveness And Knowledge Retention: A Comparative Study Of Two U.S. Air Force Computer-Based Training (Cbt) Courses For Network User Licensing, Matthew J. Imperial

Theses and Dissertations

The United States Air Force (USAF) currently employs the use of computer-based training (CET) across a host of requirements. One such requirement is in the Information Assurance (IA) arena and involves the training/licensing of over one-million computer network end-users. USAF use of CETs has been shown to possess a potential for substantial fiscal savings. However, studies investigating the learning outcomes of learning effectiveness (initial learning) and knowledge retention (sustained learning) associated with USAF CETs are lacking.

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The Effects Of Technology Turnover On Workplace Productivity Perceptions, Robert W. Povlich Jr. Mar 2003

The Effects Of Technology Turnover On Workplace Productivity Perceptions, Robert W. Povlich Jr.

Theses and Dissertations

The productivity paradox is a theory that suggests that investments in Information Technology (IT) do not necessarily lead to associated gains in the productivity of the organization (Malakoff 2000; Hitt and Brynjolfsson, 1996). This perception leads practitioners to question if acquiring new IT systems for the sake of having the latest technology will make their organization any more productive (Liebmann, 1996). Understanding the problem that is facing the practitioners, this research was undertaken to attempt to answer some of the underlying questions relating to the perceptions held about the relationship between IT expenditures and workplace productivity with respect to Air …

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