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Articles 7021 - 7050 of 8341

Full-Text Articles in Physical Sciences and Mathematics

Impact Of A Historical Translocation On Populations Of White-Tailed Deer Odocoileus Virginianus, Nathan Kendall Boddie Aug 2001

Impact Of A Historical Translocation On Populations Of White-Tailed Deer Odocoileus Virginianus, Nathan Kendall Boddie

Theses and Dissertations

Randomly amplified polymorphic DNA (RAPD) analysis was used to study the impact of a historical translocation event on populations of white-tailed deer in Georgia. The technique may also serve as a model by which management practices for other rare species can be studied. Populations from an original translocation source in Wisconsin, another Wisconsin population, and three populations in Georgia were sampled during management hunts. RAPD PCR was used to produce a genetic fingerprint for individuals of each population. Resulting band data were analyzed using PHYLIP genetic analysis software. A consensus tree of 100 bootstrapped replicates showed significant similarity between Georgia …

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Contributions From Mafic Alkaline Magmas To The Bingham Porphyry Cu-Au-Mo Deposit, Utah, U.S.A., Daniel T. Maughan Jul 2001

Contributions From Mafic Alkaline Magmas To The Bingham Porphyry Cu-Au-Mo Deposit, Utah, U.S.A., Daniel T. Maughan

Theses and Dissertations

The Bingham porphyry Cu-Au-Mo deposit, Utah, may only be world-class because of substantial contributions of sulfur and metals from mafic alkaline magma to an otherwise unremarkable calc-alkaline system. Volcanic mafic alkaline rocks in the district are enriched in Cr, Ni, and Ba as well as ore-related constituents of Cu, Au, platinum group elements (PGE) and S. The bulk of the volcanic section that is comagmatic with ore-related porphyries is dacitic to trachytic in composition, but has inherited the geochemical signature of high Cr, Ni, and Ba from magma mixing with the mafic alkaline rocks. The volcanic section that most closely …

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Single-Sided Noninvasive Inspection Of Multielement Sample Using Fan-Beam Multiplexed Compton Scatter Tomography, Matthew A. Lange Jun 2001

Single-Sided Noninvasive Inspection Of Multielement Sample Using Fan-Beam Multiplexed Compton Scatter Tomography, Matthew A. Lange

Theses and Dissertations

As aircraft age, corrosion forms upon unobservable surfaces, particularly at the junction of the sheet aluminum and the steel rivets used to attach the sheets to the airframe, degrading the aircraft s airworthiness. Previous research developed a noninvasive technique for the evaluation of the material composition of aluminum surfaces, utilizing the information encoded in the energy spectra of Compton-scattered gamma emissions. The spectra are gathered by a six-element, high purity germanium detector array. A, first principles, deterministic computer code is used to reconstruct a two-dimensional map of the electron density of aluminum samples. Previous efforts, to image pure aluminum samples, …

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Time-Resolved Photoluminescence Of Inas/Gainsb Quantum Well Lasers, Michael R. Mckay Jun 2001

Time-Resolved Photoluminescence Of Inas/Gainsb Quantum Well Lasers, Michael R. Mckay

Theses and Dissertations

In the world of semiconductor photonic device fabrication, one important objective may be to extract as much light as possible from the device. In these devices, photons are created when electrons recombine with holes by transitioning from a high-energy state to a lower one. Unfortunately, electron-hole recombination does not always result in the formation of a photon. There are three basic types of recombination: the first results in the formation of a photon and is called radiative recombination; and the second and third, known as Shockley-Read-Hall and Auger recombination, result in the heating of the device and do not produce …

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An All-To-All Multicast Routing Protocol In A Wireless Ad-Hoc Network To Improve Channel Utilization, Zhong Hua Zhou May 2001

An All-To-All Multicast Routing Protocol In A Wireless Ad-Hoc Network To Improve Channel Utilization, Zhong Hua Zhou

Theses and Dissertations

Wireless Ad-hoc network has become more and more popular. Several different multicasting schemes for this type of network have been developed. But most of them are targeting a situation where the total number of senders is much less than the total number of receivers. This thesis analyzes different wireless communication patterns in ad hoc network, the trend for wireless communication and presents a new multicast scheme. It targets an ad-hoc network where all mobile hosts act as both senders and receivers. The proposed scheme in this thesis will reduce overheads by combining data packets that are destined for the same …

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Hidden Markov Models For Visual Speech Synthesis In Limited Data, Harold A. Arb Mar 2001

Hidden Markov Models For Visual Speech Synthesis In Limited Data, Harold A. Arb

Theses and Dissertations

This work presents a new approach for estimating control points (facial locations that control movement) to allow the artificial generation of video with apparent mouth movement (visual speech) time-synced with recorded audio. First, Hidden Markov Models (HMMs) are estimated for each visual speech category (viseme) present in stored video data, where a category is defined as the mouth movement corresponding to a given sound and where the visemes are further categorized as trisemes (a viseme in the context of previous and following visemes). Next, a decision tree is used to cluster and relate states in the HMMs that are similar …

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Spectroscopic Constants, Lifetimes And Predissociation Rates For Bi2A(0+U), Michael W. Dolezal Mar 2001

Spectroscopic Constants, Lifetimes And Predissociation Rates For Bi2A(0+U), Michael W. Dolezal

Theses and Dissertations

More than 100,000 spectral features from a Bi2(X1 Σ+g → A(0+u)) absorption spectrum, encompassing 0 ≤ v' ≤ 91, 0 ≤ v" ≤ 7 and J2(A). Ground state constants, reported by Barrow et al. [1], remain unchanged. The new constants are used to redefine the A-state potential using traditional RKR methods and to set the dissociation energy at De = 29,913 cm"1, which correlates A-state dissociation products to 4S + 2D atoms. A pulsed dye laser apparatus was used to obtain lifetime data for Bi2A(0+u) …

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Evolution Of Cloud-To-Ground Lightning Discharges In Tornadic Thunderstorms, Wendy L. Seaman Mar 2001

Evolution Of Cloud-To-Ground Lightning Discharges In Tornadic Thunderstorms, Wendy L. Seaman

Theses and Dissertations

Air Force operations are directly impacted by weather on a daily basis. Erroneous forecasts negatively impact mission readiness and consequently cost the government time, in terms of wasted man-hours, and money. Advanced forecast lead-time could make a difference to minimize loss to both USAF personnel and assets. This study examined lightning data from 64 storm events from 1995-2000 in search of unique lightning signatures indicative of tornadic activity. Overall flash rates, percentage of positive flashes, positive and negative peak currents and multiplicity for each case were separated into two categories based on tornado intensity and season of occurrence. Based on …

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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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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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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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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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Models For Data Source Tracking With Xml, Teoman Yoruk Mar 2001

Models For Data Source Tracking With Xml, Teoman Yoruk

Theses and Dissertations

The Air Force Research arch Laboratory, Sensors Directorate Electronic Warfare Simulation Branch (APRL/SNZW) is responsible for developing and maintaining real-world and hypothetical scenarios for an array of threat engagement simulation systems. The general for scenario creation involves mapping from real-world databases and operations plans to specific fields in the input files represent the scenario. As part of the AFRL/SNZW's overall initiative for the development of a Concurrent Engineering Real-Time database CORrelation tool (CERCORT), as important to the scenario files themselves is the capability to trace hack to the source of data for the scenario fields. Acquiring this capability consequently results …

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Spectral And Temporal Characterization Of High Temperature Events, William F. Bagby Mar 2001

Spectral And Temporal Characterization Of High Temperature Events, William F. Bagby

Theses and Dissertations

The remote observations of the temporal and spectral characteristics of the infrared (IR) emissions from exploding ordnance have been correlated with explosion conditions. A Bomem MR-154 Fourier Transform Interferometer with two detectors, InSb and HgCdTe, was used to record spectra in the 1.3 - 20 micrometers range. Data was collected at spectral resolutions of 16/cm and 4/cm, and temporal resolutions of 0.045 sand 0.123 5, respectively. The data files range in size from 900 Kilobytes to several Megabytes. These are reduced to 2-dimensional representations of temporal features that are less than 100 Kilobytes. The data analysis indicates the possibility of …

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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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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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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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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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Dissolution Of Chromium From Inhalable Primer Paint Particles Into A Simulated Lung Fluid, David A. Kauth Mar 2001

Dissolution Of Chromium From Inhalable Primer Paint Particles Into A Simulated Lung Fluid, David A. Kauth

Theses and Dissertations

The use of chromate as a corrosion inhibitor in primer paint is an essential component for the protection of aluminum-skinned aircraft and the primary source of hexavalent chromium (Cr (VI)) exposure to USAF aircraft painters. The objective of this research was to quantify the dissolution of chromate from freshly sprayed paint particles into a simulated lung fluid (SLF). Two primer paints were sprayed with a paint spray gun to generate overspray particles for collection into impingers filled with SLF. Particles were allowed to soak in SLF for 24 and 48 hours and then the particles were removed by centrifugation. The …

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Malicious Hackers: A Framework For Analysis And Case Study, Laura J. Kleen Mar 2001

Malicious Hackers: A Framework For Analysis And Case Study, Laura J. Kleen

Theses and Dissertations

Recent years have seen an increase in the number and severity of Information Operations (IO) attacks upon DoD resources. At a higher level, the US as a whole has come under cyber attack by individuals and groups seeking thrills, monetary gain, publicity for their causes, and myriad other goals. This effort develops a first cut model of individual hacker mentality that can be utilized to improve threat assessment, mitigate Information Assurance (IA) vulnerabilities, and improve risk assessment. Further, it is a first step toward automated characterization of Information Warfare (IW) attacks based upon hacker types. All hackers are not 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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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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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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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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Optimization Of Palladium-Catalyzed In Situ Destruction Of Trichloroethylene-Contaminated Groundwater Using A Genetic Algorithm, Manuel Fernandez Mar 2001

Optimization Of Palladium-Catalyzed In Situ Destruction Of Trichloroethylene-Contaminated Groundwater Using A Genetic Algorithm, Manuel Fernandez

Theses and Dissertations

Conventional technologies for the treatment of groundwater contaminated with chlorinated solvents have limitations that have motivated development of innovative technologies. One such technology currently under development involves using palladium-on-alumina (Pd/Al) as a catalyst to promote dechlorination. Pd/Al catalyst may be used in-well as part of a re-circulating horizontal flow treatment well (HFTW) system. An HFTW system involves two or more dual-screened wells, with in-well reactors, to capture and treat contaminated groundwater without the need to pump the water to the surface. In this study, objective and fitness functions, based on system costs and TCE concentration requirements, were developed to optimize …

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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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A Traffic Pattern-Based Comparison Of Bulk Image Request Response Times For A Virtual Distributed Laboratory, David B. Hooten Mar 2001

A Traffic Pattern-Based Comparison Of Bulk Image Request Response Times For A Virtual Distributed Laboratory, David B. Hooten

Theses and Dissertations

Various agencies throughout the Department of Defense possess intelligence imagery and electrooptical signature data required by researchers in the field of automatic target recognition (ATR). The Air Force Research Laboratory, Sensors Directorate, as been tasked with creating a virtual distributed laboratory (VDL) which will make this data available to ATR researchers via high speed networks such as the defense research and engineering network (DREN). For this research, a model for simulating potential operational network configurations and collaboration scenarios was developed and implemented using OPNET. The results of the simulations were analyzed using statistical methods to determine the impact on performance …

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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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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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Using A Distributed Object-Oriented Database Management System In Support Of A High-Speed Network Intrusion Detection System Data Repository, Phillip W. Polk Mar 2001

Using A Distributed Object-Oriented Database Management System In Support Of A High-Speed Network Intrusion Detection System Data Repository, Phillip W. Polk

Theses and Dissertations

The Air Force has multiple initiatives to develop data repositories for high-speed network intrusion detection systems (IDS). All of the developed systems utilize a relational database management system (RDBMS) as the primary data storage mechanism. The purpose of this thesis is to replace the RDBMS in one such system developed by AFRL, the Automated Intrusion Detection Environment (AIDE), with a distributed object-oriented database management system (DOODBMS) and observe a number of areas: its performance against the RDBMS in terms of IDS event insertion and retrieval, the distributed aspects of the new system, and the resulting object-oriented architecture. The resulting system, …

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