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Air Force Institute of Technology

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Articles 2191 - 2220 of 3052

Full-Text Articles in Physical Sciences and Mathematics

Effects On The Red-Cockaded Woodpecker From Various Spatial And Temporal Applications Of Management Practices, Chad F. Schroeder Mar 2001

Effects On The Red-Cockaded Woodpecker From Various Spatial And Temporal Applications Of Management Practices, Chad F. Schroeder

Theses and Dissertations

The Red-Cockaded Woodpecker (RCW) is an endangered species endemic to southeastern pine forests in the United States. RCWs are cooperative breeding birds that live together in clusters of old-growth pine trees in which they construct their nesting cavities. The cavities are constructed in living pines, which are predominantly longleaf pines. RCWs also forage upon older pines, preferably longleaf pine. The Endangered Species Act, along with other DoD regulations, requires DoD installations to protect the RCWs and restore their habitat. A popular management practice converts off-site (non-native) pines back to a region's indigenous pines. Conversion provides the best long term RCW …

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Implementation And Analysis Of The Parallel Genetic Rule And Classifier Construction Environment, David M. Strong Mar 2001

Implementation And Analysis Of The Parallel Genetic Rule And Classifier Construction Environment, David M. Strong

Theses and Dissertations

This paper discusses the Genetic Rule and Classifier Construction Environment (GRaCCE), which is an alternative to existing decision rule induction (DRI) algorithms. GRaCCE is a multi-phase algorithm which uses evolutionary search to mine classification rules from data. The current implementation uses a genetic algorithm based 0/1 search to reduce the number of features to a minimal set of features that make the most significant contributions to the classification of the input data set. This feature selection increases the efficiency of the rule induction algorithm that follows. However, feature selection is shown to account for more than 98 percent of the …

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Photoluminescence Of Single Quantum Well Structures In Gallium Arsenide, Christian A. Bartholomew Mar 2001

Photoluminescence Of Single Quantum Well Structures In Gallium Arsenide, Christian A. Bartholomew

Theses and Dissertations

The continued development of state-of the-art semiconductor technologies and devices by the United States Air Force and the Department of Defense requires accurate and efficient techniques to evaluate and model these new materials. Of particular interest to the Air Force are quantum well structures which can be used for small-scale laser sources in fly-by-light applications, as efficient infrared countermeasures to heat-seeking missiles, or as advanced seekers in optically guided missiles. This thesis provides the initial experimental procedures and data necessary to begin producing accurate yet robust models. Although carrier effective masses could not be evaluated using hot-electron photoluminescence, photoluminescence excitation …

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Modeling Information Assurance, Joseph E. Beauregard Mar 2001

Modeling Information Assurance, Joseph E. Beauregard

Theses and Dissertations

The ever-increasing speed of information systems allows decision-makers around the world to gather, process, and disseminate information almost instantaneously. However, with this benefit there comes a price. Information is valuable and therefore a target to those who do not have it or wish to destroy it. The Internet has allowed information to flow freely, but it has also made information vulnerable to many forms of corruption. The U. S. military controls much of the world's most sensitive information, and since it cannot sacrifice losing the speed at which this information is currently processed and disseminated, it must find a way …

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Numerical Study Of Optical Delay In Semiconductor Multilayer Distributed Bragg Reflector And Tunable Microcavity Structures, Michael I. K. Etan Mar 2001

Numerical Study Of Optical Delay In Semiconductor Multilayer Distributed Bragg Reflector And Tunable Microcavity Structures, Michael I. K. Etan

Theses and Dissertations

The Air Force has a growing need for the greater bandwidth, speed, and flexibility offered by optical communication links. Future space systems and airborne platforms will most likely use optical signals for efficient power transmission and to minimize the possibility of spoofing and eavesdropping. Tunable optical delays play an important role in the implementation of free space optical communication links. The primary challenge in implementing these systems is the active maintenance of coherent wave fronts across the system's optical aperture. For space applications, this aperture may he hundreds of meters in diameter. Spatial segmentation of a large aperture into smaller …

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Atmospheric Conditions Associated With Lightning During Snow And Ice Events, Randall J. Haeberle Mar 2001

Atmospheric Conditions Associated With Lightning During Snow And Ice Events, Randall J. Haeberle

Theses and Dissertations

The purpose of this research was to find the atmospheric mechanisms associated with lightning in snow and ice events. The specific mechanisms that were examined were low-level wind shear, upper level divergence, surface temperature, low-level temperature, the -10 ° C level, and precipitable water. A chi-squared dependency test showed the strong association of low-level wind shear to each precipitation type (snow, sleet/freezing rain, rain) in two separate studies. Surface temperature appeared to have a relationship to lightning in all precipitation categories, while no significant relationship to lightning in all precipitation categories, while no significant relationship was found with upper level …

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A Radial Basis Function Neural Network Approach To Two-Color Infrared Missile Detection, Kin-Weng Chan Mar 2001

A Radial Basis Function Neural Network Approach To Two-Color Infrared Missile Detection, Kin-Weng Chan

Theses and Dissertations

Multicolor infrared imaging missile-warning systems require real-time detection techniques that can process the wide instantaneous field of regard of focal plane array sensors with a low false alarm rate. Current technology applies classical statistical methods to this problem and ignores neural network techniques. Thus the research reported here is novel in that it investigates the use of radial basis function (RBF) neural networks to detect sub-pixel missile signatures. An RBF neural network is designed and trained to detect targets in two-color infrared imagery using a recently developed regression tree algorithm. Features are calculated for 3 by 3 pixel sub-images in …

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Comparative Analysis Of Traditional Versus Computer-Based Survey Instrument Response, Albert E. Franke Iv Mar 2001

Comparative Analysis Of Traditional Versus Computer-Based Survey Instrument Response, Albert E. Franke Iv

Theses and Dissertations

The purpose of this study was to determine if survey medium (paper versus computer) affected responses and response rates in Air Force personnel. The study compared responses and response rates from 900 randomly selected Air Force active-duty members using a paper-based survey, a computer-based survey, and a more complex computer-based survey. The first computer-based survey minimized the differences between itself and the paper-based survey to more accurately quantify any bias due solely to the computer medium. The more complex survey served to maximize differences between itself and the other computer-based survey to more accurately quantify any bias due to programmatic …

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Control And Characterization Of Line-Addressable Micromirror Arrays, Harris J. Hall Mar 2001

Control And Characterization Of Line-Addressable Micromirror Arrays, Harris J. Hall

Theses and Dissertations

This research involved the design and implementation of a complete line-addressable control system for a 32x32 electrostatic piston-actuated micromirror array device. Line addressing reduces the number of control lines from N2 to 2N making it possible to design larger arrays and arrays with smaller element sizes. The system utilizes the electromechanical bi-stability of individual elements to bold arbitrary bi-stable phase patterns. The control system applies pulse width modulated (PWM) signals to the rows and columns of the micromirror array. Three modes of operation were conceived and built into the system. The first was the traditional signal scheme which requires …

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Solving The Protein Structure Prediction Problem With Fast Messy Genetic Algorithms (Scaling The Fast Messy Genetic Algorithm To Medium-Sized Peptides By Detecting Secondary Structures), Steven R. Michaud Mar 2001

Solving The Protein Structure Prediction Problem With Fast Messy Genetic Algorithms (Scaling The Fast Messy Genetic Algorithm To Medium-Sized Peptides By Detecting Secondary Structures), Steven R. Michaud

Theses and Dissertations

The ability to accurately predict a polypeptide's molecular structure given its amino acid sequence is important to numerous scientific, medical, and engineering applications. Studies have been conducted in the application of Genetic Algorithms (GAs) to this problem with promising initial results. In this thesis report, we use the fast messy Genetic Algorithm (fmGA) to attempt to find the minimization of an empirical CHARMM energy model and generation of the associated conformation. Previous work has shown that the fmGA provided favorable results, at least when applied to the pentapeptide Met-Enkephalin. We extend these results to a larger Polyalinine peptide by utilizing …

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Traveling Salesman Problem For Surveillance Mission Using Particle Swarm Optimization, Barry R. Secrest Mar 2001

Traveling Salesman Problem For Surveillance Mission Using Particle Swarm Optimization, Barry R. Secrest

Theses and Dissertations

The surveillance mission requires aircraft to fly from a starting point through defended terrain to targets and return to a safe destination (usually the starting point). The process of selecting such a flight path is known as the Mission Route Planning (MRP) Problem and is a three-dimensional, multi-criteria (fuel expenditure, time required, risk taken, priority targeting, goals met, etc.) path search. Planning aircraft routes involves an elaborate search through numerous possibilities, which can severely task the resources of the system being used to compute the routes. Operational systems can take up to a day to arrive at a solution due …

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Validation And Assessment Of Dmsp Electron Temperatures In The Topside Ionosphere, Bradford S. Green Mar 2001

Validation And Assessment Of Dmsp Electron Temperatures In The Topside Ionosphere, Bradford S. Green

Theses and Dissertations

Geomagnetic disturbances in the near earth space environment can adversely affect numerous military and Department of Defense (DoD) systems and operations. To improve the prediction accuracy of such disturbances, the next generation of space environment forecast models aims to automatically ingest real-time ionospheric measurements. This research validates and assesses one such measurement - the Defense Military Satellite Program (DMSP) measured electron temperature (Te). DMSP Te data were validated against near simultaneous incoherent scatter radar (ISR) Te measurements from Millstone Hill, MA and Sondrestrom, Greenland between Winter 1996 and Summer 2000. Of the 37 Millstone and six …

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An Objective Evaluation Of Four Sar Image Segmentation Algorithms, Jason B. Gregga Mar 2001

An Objective Evaluation Of Four Sar Image Segmentation Algorithms, Jason B. Gregga

Theses and Dissertations

Because of the large number of SAR images the Air Force generates and the dwindling number of available human analysts, automated methods must be developed. A key step towards automated SAR image analysis is image segmentation. There are many segmentation algorithms, but they have not been tested on a common set of images, and there are no standard test methods. This thesis evaluates four SAR image segmentation algorithms by running them on a common set of data and objectively comparing them to each other and to human segmentors. This objective comparison uses a multi-metric a approach with a set of …

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A Process For Vectoring Offensive Information Warfare As A Primary Weapon Option Within The United States Air Force, Sheila G. Bennett Mar 2001

A Process For Vectoring Offensive Information Warfare As A Primary Weapon Option Within The United States Air Force, Sheila G. Bennett

Theses and Dissertations

Consistently and comprehensively using Information Operations (IO) capabilities as primary weapon option within the Air Force is the next step to operationalizing IO within the Air Force. Doctrine and official guidance has set the variables of mission and concepts of operations, organizational structure, and IW players in place. The missing variable to operationalizing IO and probably the most difficult is the 'how' or process of the equation. This research will introduce a useable process that can be incorporated within the Air Force for integrating offensive IW activities into the current and given environment. The process is the basis for further …

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A Semantic Interface To Scenario Component Reuse In Dod Simulation Systems, Lawrence A. Breighner Mar 2001

A Semantic Interface To Scenario Component Reuse In Dod Simulation Systems, Lawrence A. Breighner

Theses and Dissertations

The Department of Defense utilizes various simulation systems to model employment of forces and weapons systems in operational environments. The data files that model these environments and weapons systems are extremely large and complex, and require many person-hours to develop. Compounding the problem, these data files are distributed across multiple systems in a heterogeneous environment. Currently, there is no automated means of identifying and retrieving reusable portions of these files for reuse in a new scenario under development. This work develops a multi-agent system that catalogs the files, and provides the user with a means of identifying and retrieving reusable …

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Validation And Characterization Of Ionospheric Densities Measured By Dmsp, Herbert L. Keyser Mar 2001

Validation And Characterization Of Ionospheric Densities Measured By Dmsp, Herbert L. Keyser

Theses and Dissertations

Future models of the thermosphere-ionosphere-magnetosphere system will require near real-time assimilation of ionospheric parameters to specify% and forecast these regions One of the current sensors that will be used in the GAIM model is the DMSP SSIES. Knowledge of the SSIES's reliability and data characteristics is key to using the data when relying on automated processes to ingest the data. To validate the DMSP value, the DMSP-measured density is compared to ground-based ISR measurements from solar minimum to solar maximum. The DMSP data are compared to data from the ISRs located at the Millstone Hill Observatory in Massachusetts and Sondrestrom …

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The Effects Of Budgetary Constraints, Multiple Strategy Selection, And Rationality On Equilibrium Attainment In An Information Warfare Simulation, Steven W. Tait Mar 2001

The Effects Of Budgetary Constraints, Multiple Strategy Selection, And Rationality On Equilibrium Attainment In An Information Warfare Simulation, Steven W. Tait

Theses and Dissertations

Information warfare (IW) has developed into a significant threat to the national security of the United States. Our critical infrastructures, linked together by information systems, are increasingly vulnerable to information attack. This study seeks to understand some of those factors which affect the ability of an individual to make accurate decisions in an IW environment. The study used game theory to analyze the behavior of decision-makers within an IW simulation. The IW game model is based on a set of games known as infinitely repeated games of incomplete information. It uses the Bayesian Nash equilibrium concept to determine the strategy …

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An Analysis Of The Computer And Network Attack Taxonomy, Richard C. Daigle Mar 2001

An Analysis Of The Computer And Network Attack Taxonomy, Richard C. Daigle

Theses and Dissertations

The Air Force's dependence on the Internet continues to increase daily. However, this increased dependence comes with risks. The popularity and potential of the Internet attracts users with illegal as well as legal intentions. Since the Air Force considers the Internet an integral component of its information Operations strategy, the Air Force must be confident that it can trust the security of this component. Therefore, reliable methods and information that helps the Air Force classify the risks associated with the Internet can help the Air Force determine the best processes to assure the security of its use of this resource. …

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Analysis Of Cloud-Free Line-Of-Sight Probability Calculations, Joseph J. Golemboski Iii Mar 2001

Analysis Of Cloud-Free Line-Of-Sight Probability Calculations, Joseph J. Golemboski Iii

Theses and Dissertations

Cloud-free line-of-sight probabilities were calculated using two separate methods. The first was a variation of a method developed by the Rand Corporation in 1972. In it, CFLOS probabilities were calculated using empirical data based on five years of photograms taken over Columbia, Missouri and forecasted cloud amounts rather than climatological values. The second was a new approach using the Cloud Scene Simulation Model developed by Phillips Laboratory. Cloud scenes were generated using forecasted cloud fields, meteorological inputs, and thirty random numbers. Water content files were produced and processed through a follow-on program to determine the extinction coefficients at each grid …

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Simulating Wet Deposition Of Radiocesium From The Chernobyl Accident, Aaron M. Kinser Mar 2001

Simulating Wet Deposition Of Radiocesium From The Chernobyl Accident, Aaron M. Kinser

Theses and Dissertations

In response to the Chernobyl nuclear power plant accident of 1986, a cesium-137 deposition dataset was assembled. Most of the airborne Chernobyl cesium was wet deposited, either via interception by falling raindrops or via absorption into cloud droplets destined to become raindrops. The Hybrid Single-Particle Lagrangian rated Transport (HYSPLIT) model, developed at Air Resources Laboratory, is used to simulate the transport and deposition of Chernobyl cesium-137. A cloud base parameterization modification is tested and appears to slightly improve the accuracy of one HYSPLIT simulation of daily Chernobyl cesium-137 deposition over the course of the accident at isolated European sites, and …

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The Affect Of Varying Arousal Methods Upon Vigilance And Error Detection In An Automated Command And Control Environment, Brent T. Langhals Mar 2001

The Affect Of Varying Arousal Methods Upon Vigilance And Error Detection In An Automated Command And Control Environment, Brent T. Langhals

Theses and Dissertations

This study focused on improving vigilance performance through developing methods to arouse subjects to the possibility of errors in a data manipulation information warfare attack. The study suggests that by continuously applying arousal stimuli, subjects would retain initially high vigilance levels thereby avoiding the vigilance decrement phenomenon and improving error detection. The research focused on which methods were the most effective as well the impact of age upon the arousability of the subjects. Further the implications of vigilance and vigilance decrement for correct detections as well as productivity were explored. The study used a simulation experiment to provide a vigilance …

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Lifecycle Energy And Air Emission Differences Between Electric And Internal Combustion Vehicles, David L. Mccleese Mar 2001

Lifecycle Energy And Air Emission Differences Between Electric And Internal Combustion Vehicles, David L. Mccleese

Theses and Dissertations

The U.S. Federal Government has encouraged shifting from internal combustion engine vehicles (ICEVs) to electric vehicles (EVs) with three objectives, reducing foreign oil dependence, greenhouse gas emissions, and criteria pollutant emissions. This thesis uses Monte Carlo simulation to predict lifecycle emissions and energy consumption differences per kilometer driven from replacing ICEVs with three EV options: lead acid, nickel cadmium (Ni-Cd), and nickel metal hydride (NiMH). All three EV options reduce U.S. foreign oil dependence by shifting to domestic coal. The probabilities that lifecycle energy consumption per km driven improve are lead acid 76%, Ni-Cd 64%, and NiMH 90%. The probabilities …

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Selecting A Software Engineering Methodology Using Multiobjective Decision Analysis, Scott A. O'Malley Mar 2001

Selecting A Software Engineering Methodology Using Multiobjective Decision Analysis, Scott A. O'Malley

Theses and Dissertations

With the emergence of agent-oriented software engineering methodologies, software developers have a new set of tools to solve complex software requirements. One problem software developers face is to determine which methodology is the best approach to take to developing a solution. A number of factors go into the decision process. This thesis defines a decision making process that can be used by a software engineer to determine whether or not a software engineering approach is an appropriate system development strategy. This decision analysis process allows the software engineer to classify and evaluate a set of methodologies while specifically considering the …

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Analysis Of Cloud-To-Ground Lightning Clusters With Radar Composite Imagery, Rhonda B. Scott Mar 2001

Analysis Of Cloud-To-Ground Lightning Clusters With Radar Composite Imagery, Rhonda B. Scott

Theses and Dissertations

The most recent research conducted at the Air Force Institute of Technology involved studying a large volume of lightning data without coupling radar imagery (Parsons 2000). Parsons finding could not be acted on because no individual storms were studied. The primary goal of this research is to determine whether the techniques used by Parsons can be applied to storms by examining the radar imagery and lightning data. This research used the methodology applied to lightning data by Parsons and radar imagery to determine whether the location of lightning clusters were located near storms. A composite reflectivity radar image was generated …

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A Model For Palladium Catalyzed Destruction Of Chlorinated Ethenes In Contaminated Groundwater, Christopher M. Stoppel Mar 2001

A Model For Palladium Catalyzed Destruction Of Chlorinated Ethenes In Contaminated Groundwater, Christopher M. Stoppel

Theses and Dissertations

Groundwater contamination by chlorinated ethenes is a widespread environmental problem. Conventional remediation technologies have shortcomings that have prompted further research into the development of novel treatment technologies. A palladium/ alumina catalyst in the presence of dissolved molecular hydrogen (referred to hereafter as a PD/H2 system) has been demonstrated to rapidly destroy chlorinated ethene contaminated groundwater. First-order kinetics have been used to model chlorinated ethene destruction in a PD/H2 reactor. However, catalyst deactivation and regeneration are important processes that also need to be modeled in order to better understand their effect on treatment efficiency. This study presents a model …

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Minimum Distance Estimation For Time Series Analysis With Little Data, Hakan Tekin Mar 2001

Minimum Distance Estimation For Time Series Analysis With Little Data, Hakan Tekin

Theses and Dissertations

Minimum distance estimate is a statistical parameter estimate technique that selects model parameters that minimize a good-of-fit statistic. Minimum distance estimation has been demonstrated better standard approaches, including maximum likelihood estimators and least squares, in estimating statistical distribution parameters with very small data sets. This research applies minimum distance estimation to the task of making time series predictions with very few historical observations. In a Monte Carlo analysis, we test a variety of distance measures and report the results based on many different criteria. Our analysis tests the robustness of the approach by testing its ability to make predictions when …

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Development Of Predictors For Cloud-To-Ground Lightning Activity Using Atmospheric Stability Indices, Kenneth C. Venzke Mar 2001

Development Of Predictors For Cloud-To-Ground Lightning Activity Using Atmospheric Stability Indices, Kenneth C. Venzke

Theses and Dissertations

A detailed examination was performed on several commonly applied atmospheric stability indices and lightning activity from 1993 to 2000 to determine the indices usefulness as predictive tools for determining cloud-to-ground lightning activity. Predetermined radii of 50 nautical miles around upper-air stations in the Midwest U.S. were used for the lightning summaries. Also explored is an improvement upon the commonly accepted thresholds of the stability indices as general thunderstorm indicators. An improvement was found and new threshold ranges were developed for relating stability index values to lightning occurrence. Traditional statistical regression methods failed to find a significant predictive relationship. By examining …

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Assessment Of The Effects Of Entrainment And Wind Shear On Nuclear Cloud Rise Modeling, Daniel E. Zalewski Mar 2001

Assessment Of The Effects Of Entrainment And Wind Shear On Nuclear Cloud Rise Modeling, Daniel E. Zalewski

Theses and Dissertations

The Missile Defense Agency (MDA) plans to construct, during a two-week period, an X-Band Radar (XBR) on Shemya, AK. Wind speeds must not, at any time during the construction, exceed a 25 knot limit set by the MDA for lifting the massive dome panels into place. The goal of this research was to explore the possibilities of long-range forecasts to determine the feasibility of predicting any upcoming two-week windows of opportunity, well in advance, that will ensure the successful completion of constructing the XBR on Shemya. In order to reach this goal, the following objectives were achieved; (1) a climatological …

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The Effect Of Contextual-Based Training On Artifact-Based Deception Detection, Elizabeth A. Autrey Mar 2001

The Effect Of Contextual-Based Training On Artifact-Based Deception Detection, Elizabeth A. Autrey

Theses and Dissertations

Air Force dependence on information technology (IT) creates vulnerabilities that it cannot ignore. With global availability of commercial IT and the Internet, the Air Force does not necessarily have the high technological advantage over potential adversaries that it once had. Furthermore, it is possible to directly and covertly manipulate information within information systems, or artifacts, without notice. This directly affects decision makers since the availability and integrity of information is critical. Air Force physical and network security measures taken to protect its information do not guarantee detection of direct information manipulation. This leaves it to information artifact users to detect …

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Investigation Of Gravity Waves Via The Rotational Temperature Of Hydroxyl Nightglow, Erin C. Willingham Mar 2001

Investigation Of Gravity Waves Via The Rotational Temperature Of Hydroxyl Nightglow, Erin C. Willingham

Theses and Dissertations

Measurement of the vibration and rotation bands of mesospheric hydroxyl radicals (OH) has been conducted during the past two decades using ground-based and space-based interferometers to take temperature and wind measurements from 70-100km in altitude. Gravity waves that pass through the mesosphere can be measured by determining the variance over time of the rotational temperature of the OH emissions. Several attempts were made to take spectrum measurements of the nightglow from hydroxyl radicals in the mesosphere using a custom hardware configuration that included a telescope and grating monochrometer optimized for the visible and near infrared. Quantifying gravity wave activity was …

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