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Air Force Institute of Technology

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Articles 2071 - 2100 of 3055

Full-Text Articles in Physical Sciences and Mathematics

Surveying Cost Growth, Michael A. Greiner, Vince Sipple, Edward D. White Jan 2004

Surveying Cost Growth, Michael A. Greiner, Vince Sipple, Edward D. White

Faculty Publications

Cost growth that weapon systems incur throughout their acquisition life cycle concerns those who work in the acquisition environment. One way to reduce the amount of unexpected cost growth is to develop better cost estimates. In attaining better cost estimates though, it is often helpful to understand and account for potential cost drivers. Several cost studies, some of which specifically focus on the aircraft industry, have been performed documenting and investigating these growth factors. Overviews of these various cost growth studies are presented as other tools for the cost estimators and program managers.

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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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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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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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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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Explicit Building-Block Multiobjective Genetic Algorithms: Theory, Analysis, And Developing, Jesse B. Zydallis Mar 2003

Explicit Building-Block Multiobjective Genetic Algorithms: Theory, Analysis, And Developing, Jesse B. Zydallis

Theses and Dissertations

This dissertation research emphasizes explicit Building Block (BB) based MO EAs performance and detailed symbolic representation. An explicit BB-based MOEA for solving constrained and real-world MOPs is developed the Multiobjective Messy Genetic Algorithm II (MOMGA-II) which is designed to validate symbolic BB concepts. The MOMGA-II demonstrates that explicit BB-based MOEAs provide insight into solving difficult MOPs that is generally not realized through the use of implicit BB-based MOEA approaches. This insight is necessary to increase the effectiveness of all MOEA approaches. In order to increase MOEA computational efficiency parallelization of MOEAs is addressed. Communications between processors in a parallel MOEA …

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Inquisitive Pattern Recognition, Amy L. Magnus Mar 2003

Inquisitive Pattern Recognition, Amy L. Magnus

Theses and Dissertations

The Department of Defense and the Department of the Air Force have funded automatic target recognition for several decades with varied success. The foundation of automatic target recognition is based upon pattern recognition. In this work, we present new pattern recognition concepts specifically in the area of classification and propose new techniques that will allow one to determine when a classifier is being arrogant. Clearly arrogance in classification is an undesirable attribute. A human is being arrogant when their expressed conviction in a decision overstates their actual experience in making similar decisions. Likewise given an input feature vector, we say …

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Single-Mode Raman Fiber Laser In A Multimode Fiber, Matthew B. Crookston Mar 2003

Single-Mode Raman Fiber Laser In A Multimode Fiber, Matthew B. Crookston

Theses and Dissertations

The feasibility of a transverse single-mode Raman fiber laser using a multimode fiber has been investigated. The Raman fiber laser operates in low-order transverse modes despite the fact the fiber supports multimode beam propagation. The performance characteristics of the Raman fiber laser are compared with those of the single-pass SRS beam.

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Optical Characterization Of Antimony-Based, Types-I And Ii, Multiple Quantum-Well Semiconductor Structures For Mid-Infrared Laser Applications, Edward G. Ferguson Mar 2003

Optical Characterization Of Antimony-Based, Types-I And Ii, Multiple Quantum-Well Semiconductor Structures For Mid-Infrared Laser Applications, Edward G. Ferguson

Theses and Dissertations

This experiment characterizes antimony-based, multiple quantum-well, types-I and -II, semiconductor samples designed for laser applications. The samples emit light in the 3-5-micron range to exploit an atmospheric transmission window, making them ideal for infrared (IR)-seeking missile countermeasures. Photoluminescence (PL) spectra were collected and yielded bandgap (E(sub g)) dependence-on-temperature relationships. The type-I sample was found to follow the Varshni equation, while the type-II samples showed a rise with temperature in a portion of the curve that should be linear according to the Varshni equation. The type-II samples followed the Varshni equation well at higher temperature. The PL study indicated that the …

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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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Deterministic Intracellular Modeling, Jacqueline B. Young Mar 2003

Deterministic Intracellular Modeling, Jacqueline B. Young

Theses and Dissertations

The United States Air Force is interested in the potential side effects at the cellular level from exposure to mission-essential chemicals. Presently, Air Force toxicology studies are conducted to help shed light in identifying potential hazards to workers. However, it takes a considerable amount of money, resources, and time to obtain and analyze experimental results from toxicology studies. The necessity for innovative methods that enable researchers to more effectively generate and analyze data is apparent.

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A Three-Dimensional Heads-Up Primary Navigation Reference Display For Paratroopers Performing High Altitude High Open Jumps, Brian A. Balazs Mar 2003

A Three-Dimensional Heads-Up Primary Navigation Reference Display For Paratroopers Performing High Altitude High Open Jumps, Brian A. Balazs

Theses and Dissertations

The Department of Defense (DoD) relies on the para-dropping of resources to meet different objectives in order to accomplish missions during peace-time, war-time, or military operations other than war. The resources dropped to the ground via parachute range from supplies and equipment to the most valued asset, people. Tactics have been developed to increase the safety of troops parachuting into areas of conflict. These tactics include high-altitude high-opening (HAHO) jumping and night jumping. HAHO jumping allows paratroopers to travel large distances in the air away from the path of the delivering aircraft. While night jumping, done with the aid of …

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A Visual Language For Composable Simulation Scenarios, Carolyn R. Bartley Mar 2003

A Visual Language For Composable Simulation Scenarios, Carolyn R. Bartley

Theses and Dissertations

Modeling and Simulation plays an important role in how the Air Force trains and fights, Scenarios are used in simulation to give users the ability to specify entities and behaviors that should be simulated by a model: however, building and understanding scenarios can be a difficult and time-consuming process, furthermore, as composable simulations become more prominent, the need for a common descriptor for simulation scenarios has become evident. In order to reduce the complexity of creating and understanding simulation scenarios, a visual language was created, The research on visual languages presented in this thesis examines methods of visually specifying the …

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Performance Evaluation And Analysis Of Effective Range And Data Throughput For Unmodified Bluetooth Communication Devices, Timothy F. Kneeland Mar 2003

Performance Evaluation And Analysis Of Effective Range And Data Throughput For Unmodified Bluetooth Communication Devices, Timothy F. Kneeland

Theses and Dissertations

The DoD and the Air Force continually seek to incorporate new technology in an effort to improve communication, work effectiveness, and efficiency. Office devices utilizing Bluetooth technology simplify device configuration and communication. They provide a means to communicate wirelessly over short distances thereby eliminating the need for different vendor specific cables and interfaces. One of the key concerns involved in incorporating new communication technology is security; the fundamental security concern of wireless communication is interception. Studies focusing on IEEE 802.11b have shown vulnerability zones around many DoD installations that reflect the ranges at which wireless communications using the 802.11b standard …

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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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Distributed Control Of A Swarm Of Autonomous Unmanned Aerial Vehicles, James T. Lotspeich Mar 2003

Distributed Control Of A Swarm Of Autonomous Unmanned Aerial Vehicles, James T. Lotspeich

Theses and Dissertations

With the increasing use of Unmanned Aerial Vehicles (UAV)s military operations, there is a growing need to develop new methods of control and navigation for these vehicles. This investigation proposes the use of an adaptive swarming algorithm that utilizes local state information to influence the overall behavior of each individual agent in the swarm based upon the agent's current position in the battlespace. In order to investigate the ability of this algorithm to control UAVs in a cooperative manner, a swarm architecture is developed that allows for on-line modification of basic rules. Adaptation is achieved by using a set of …

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Searching System Call Information For Clues: The Effects Of Intrusions Of Processes, Mark G. Reith Mar 2003

Searching System Call Information For Clues: The Effects Of Intrusions Of Processes, Mark G. Reith

Theses and Dissertations

The United States Air Force extensively uses information systems as a tool managing and maintaining its information. The increased dependence on these systems in recent years has necessitated the need for protection front threats of information warfare and cyber terrorism. One type of protection utilizes intrusion detection systems to provide indications that intrusive behavior has occurred. Other types of protection may include packet filtering, cryptography and strong user authentication. Traditional approaches toward intrusion detection rely on features that are external to computer processes. By treating processes as black-boxes, intrusion detection systems may miss a wealth of information that could be …

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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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Development Of A Simplified Sustainable Facilities Guide, David F. Hargy Mar 2003

Development Of A Simplified Sustainable Facilities Guide, David F. Hargy

Theses and Dissertations

The Air Force has adopted the United States Green Building Council's Leadership in Energy and Environmental Design (LEED™) Green Building Rating System as the preferred self-assessment metric for sustainable development. LEED™ is designed for new construction and major renovations, and, within the Air Force, is most applicable for Military Construction (MILCON) projects. The Air Force Center for Environmental Excellence developed the Air Force Sustainable Facilities Guide to provide guidance and strategies to meet LEED™ requirements. The Air Force has not adopted a sustainable development guide or rating system that is most applicable for construction projects that are relatively low (compared …

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Optimizing An In Situ Bioremediation Technology To Manage Perchlorate-Contaminated Groundwater, Mark R. Knarr Mar 2003

Optimizing An In Situ Bioremediation Technology To Manage Perchlorate-Contaminated Groundwater, Mark R. Knarr

Theses and Dissertations

Combining horizontal flow treatment wells (HFTWs) with in situ biodegradation is an innovative approach with the potential to remediate perchlorate-contaminated groundwater. A technology model was recently developed that combines the groundwater flow induced by HFTWs with in situ biodegration processes that result from using the HFTWs to mix electron donor into perchlorate-contaminated groundwater. A field demonstration of this approach is planned to begin this year. In order to apply the technology in the field, project managers need to understand how contaminated site conditions and technology design parameters impact technology performance. One way to gain this understanding is to use the …

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Analysis Of Anion Distributions In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Joshua D. Kovacic Mar 2003

Analysis Of Anion Distributions In The Developing Strata Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Joshua D. Kovacic

Theses and Dissertations

Perchloroethene (PCE), Trichloroethene (TCE) and their degradation products are among the most common organic groundwater contaminants in the United States. Constructed wetlands utilizing upward flow harbor reduction-oxidation conditions that have demonstrated the potential to promote both partial and total mineralization of PCE and TCE through the process of natural attenuation. Organic acid and inorganic anion concentrations are indicative of reduction-oxidation processes that drive chlorinated ethene degradation. These analytes were investigated to assess their development within three vertically stratified regions of a constructed wetland cell at Wright-Patterson Air Force Base fed by groundwater contaminated with PCE and TCE. Data collected during …

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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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Remote Sensing Systems Optimization For Geobase Enhancement, Steve J. Paylor Mar 2003

Remote Sensing Systems Optimization For Geobase Enhancement, Steve J. Paylor

Theses and Dissertations

The U.S. Air Force is in the process of implementing GeoBase, a geographic information system (GIS), throughout its worldwide installations, Air Force GIS needs can be augmented by imagery from aerial and satellite platforms. Imagery has greatly improved over the past several years and provides high resolution coverage of features on earth. Various imagery types will significantly increase GeoBase usefulness in a range of mission requirements, Potential Air Force uses of imagery include identifying heat loss, environmental monitoring, command decision-making, and emergency response, The research develops a decision tool to determine the appropriate imagery for a given Air Force Application, …

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Redundant Discrete Wavelet Transform Based Super-Resolution Using Sub-Pixel Image Registration, Daniel L. Ward Mar 2003

Redundant Discrete Wavelet Transform Based Super-Resolution Using Sub-Pixel Image Registration, Daniel L. Ward

Theses and Dissertations

The limited resolution of video imagery taken by aircraft, over geographical areas of interest, hinders the accurate extraction of useful information. The frame resolution of the video is determined by the camera that created it. Information exists about the camera which can be used to increase frame resolution beyond the resolution capability of the camera. This is achieved by a process called super-resolution, which uses multiple low-resolution video frames to create one high-resolution image.

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Gaussian Mixture Reduction Of Tracking Multiple Maneuvering Targets In Clutter, Jason L. Williams Mar 2003

Gaussian Mixture Reduction Of Tracking Multiple Maneuvering Targets In Clutter, Jason L. Williams

Theses and Dissertations

The problem of tracking multiple maneuvering targets in clutter naturally leads to a Gaussian mixture representation of the Provability Density Function (PDF) of the target state vector. State-of-the-art Multiple Hypothesis Tracking (MHT) techniques maintain the mean, covariance and probability weight corresponding to each hypothesis, yet they rely on ad hoc merging and pruning rules to control the growth of hypotheses.

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Effect Of Multi-Mode Vibration On Signature Estimation Using A Laser Vibration Sensor, Ngoya Pepela Mar 2003

Effect Of Multi-Mode Vibration On Signature Estimation Using A Laser Vibration Sensor, Ngoya Pepela

Theses and Dissertations

A laser vibration sensor (LVS) can be used to determine the vibrational spectrum of targets such as vehicles using heterodyne laser Doppler velocimetry. The vibrational spectra of exterior skin of vehicles are known to have characteristic resonances due to the physical structure driven by motor gears and other moving parts. Each particular class of vehicle has a unique vibrational spectrum. This research shows how a body vibrating in higher order modes has the opportunity to eliminate spectral content of the target's vibrational spectrum while using an LVS to perform spectrum estimation. This is due to roughly equal amounts of laser …

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Antecedents And Outcomes Of End User Computing Competence, David A. Case Mar 2003

Antecedents And Outcomes Of End User Computing Competence, David A. Case

Theses and Dissertations

The tremendous proliferation of end user computing (EUC) in the workplace over the past few decades is cause for concern in public and private organizations. Computer use has moved from individuals working with "dumb" terminals in centralized networks to individuals operating personal computers, just as powerful as yesterday's mainframe. The end user has had to evolve and will continue evolving as well; from someone with low level technical skills to someone with a high level of technical knowledge and information managerial skills. Because EUC continues growing more sophisticated, end users must not only maintain a level of competence, but prepare …

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The Generalizability Of Private Sector Research On Software Project Management In Two Usaf Organizations: An Exploratory Study, Michael R. Garman Mar 2003

The Generalizability Of Private Sector Research On Software Project Management In Two Usaf Organizations: An Exploratory Study, Michael R. Garman

Theses and Dissertations

Project managers typically set three success criteria for their projects: meet specifications, be on time, and be on budget. However, software projects frequently fail to meet these criteria. Software engineers, acquisition officers, and project managers have all studied this issue and made recommendations for achieving success. But most of this research in peer reviewed journals has focused on the private sector. Researchers have also identified software acquisitions as one of the major differences between the private sector and public sector MIS. This indicates that the elements for a successful software project in the public sector may be different from the …

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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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