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Air Force Institute of Technology

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Articles 1801 - 1830 of 2678

Full-Text Articles in Physical Sciences and Mathematics

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 …


Reverse Geographic Location Of A Computer Node, Clinton G. Carr Iii Mar 2003

Reverse Geographic Location Of A Computer Node, Clinton G. Carr Iii

Theses and Dissertations

The determination of methods by which a user is able to locate his computer when that user does not know his current location, termed "homestation", will provide the Air Force an advantage over its adversaries. The methods are a combination of different mathematical techniques that enable the user to manipulate data to minimize the effects of delay caused by various factors on the network. The techniques use the smallest round trip time obtained from the ping utility. This time is then converted into miles and plotted on a map of the United States. The methods used to solve this problem …


An Artificial Immune System Strategy For Robust Chemical Spectra Classification Via Distributed Heterogeneous Sensors, Mark A. Esslinger Mar 2003

An Artificial Immune System Strategy For Robust Chemical Spectra Classification Via Distributed Heterogeneous Sensors, Mark A. Esslinger

Theses and Dissertations

The timely detection and classification of chemical and biological agents in a wartime environment is a critical component of force protection in hostile areas. Moreover, the possibility of toxic agent use in heavily populated civilian areas has risen dramatically in recent months. This thesis effort proposes a strategy for identifying such agents vis distributed sensors in an Artificial Immune System (AIS) network. The system may be used to complement "electronic" nose ("E-nose") research being conducted in part by the Air Force Research Laboratory Sensors Directorate. In addition, the proposed strategy may facilitate fulfillment of a recent mandate by the President …


Uml Assisted Visual Debugging For Distributed Systems, Benjamin R. Musial Mar 2003

Uml Assisted Visual Debugging For Distributed Systems, Benjamin R. Musial

Theses and Dissertations

The DOD is developing a Joint Battlespace Infosphere, linking a large number of data sources and user applications. To assist in this process, debugging and analysis tools are required. Software debugging is an extremely difficult cognitive process requiring comprehension of the overall application behavior, along with detailed understanding of specific application components. This is further complicated with distributed systems by the addition of other programs, their large size and synchronization issues. Typical debuggers provide inadequate support for this process, focusing primarily on the details accessible through source code. To overcome this deficiency, this research links the dynamic program execution state …


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 …


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 …


Palladium-Catalyzed Destruction Of Nitro Aromatic-Contaminated Groundwater, Dennis Landon Phillips Mar 2003

Palladium-Catalyzed Destruction Of Nitro Aromatic-Contaminated Groundwater, Dennis Landon Phillips

Theses and Dissertations

Of the over 17,000 DoD sites that potentially require remediation, sites containing soil and groundwater contaminated by energetic compounds are prevalent (Larson et al., 2001). Production of energetics such as 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5 - trinitro- 1,3,5 -triazine (RDX), and octahydro-1,3,5,7-tetranitro- 1,3,5,7-tetrasocine (HMX) for use in munitions has created a DoD-wide problem due to improper disposal techniques (Price et al., 2001), Nitro aromatic compounds (NACs) similar to those used in explosives can also be found in insecticides, herbicides, pharmaceuticals, dyes, plastics, and many other commonly used products. The natural breakdown of these contaminants creates byproducts such as amines, which are known …


Feature Guided Image Registration Applied To Phase And Wavelet-Base Optic Flow, Kate R. Duffy Mar 2003

Feature Guided Image Registration Applied To Phase And Wavelet-Base Optic Flow, Kate R. Duffy

Theses and Dissertations

Optic Flow algorithms are useful in problems such as computers vision, navigational systems, and robotics. However, current algorithms are computationally expensive or lack the accuracy to be effective compared with traditionally navigation systems. Recently, lower accuracy inertial navigation systems (INS) based on Microelectromechanical systems (MEMS) technology have been proposed to replace more accurate traditional navigation systems.


Forecasting Excessive Rainfall And Low-Cloud Bases East Of The Northern Andes And Mesoscale Convective Complex Movement In Central South America, Marc R. Gasbarro Mar 2003

Forecasting Excessive Rainfall And Low-Cloud Bases East Of The Northern Andes And Mesoscale Convective Complex Movement In Central South America, Marc R. Gasbarro

Theses and Dissertations

This research produces better forecast tools for SOUTHCOM's 25th Operational Weather Squadron (OWS) over multiple areas of operation in South America. Heavy rainfall and low-cloud base events along the northeastern Andes foothills are examined, as well as, mesoscale convective complexes (MCCs) in Central South America (CSA). Low clouds, fog, and flooding rains hamper daily Department of Defense (DoD) counter-drug operations in Northwestern South America (NWSA). In addition, fierce MCCs interfere with joint-military exercises in CSA.


Statistical Process Control: An Application In Aircraft Maintenance Management, Bradley A. Beabout Mar 2003

Statistical Process Control: An Application In Aircraft Maintenance Management, Bradley A. Beabout

Theses and Dissertations

Maintenance management at the 135th Airlift Wing, Maryland Air National Guard desires a visualization tool for their maintenance performance metrics. Currently they monitor their metrics via an electronic spreadsheet. They desire a tool that presents the performance information in a graphical manner. This thesis effort focuses on the development of a visualization tool utilizing two of the seven tools offered by Statistical Process Control (SPC). This research demonstrates the application of p-charts and Pareto diagrams in the aircraft maintenance arena. P-charts are used for displaying mission capable (MC) rates and flying scheduling effectiveness (FSE) rates. Pareto diagrams are then used …


A System Dynamics Investigation Of Genetic Drift And Translocation In The Red-Cockaded Woodpecker Metapopulation, Jason E. Yates Mar 2003

A System Dynamics Investigation Of Genetic Drift And Translocation In The Red-Cockaded Woodpecker Metapopulation, Jason E. Yates

Theses and Dissertations

The red-cockaded woodpecker (Picoides borealis) is classified under the Endangered Species Act of 1973 as an endangered species As such, the red-cockaded woodpecker (RCW) is afforded strict protection in an effort to return the RCW population to a self-sustainable level. Endemic to southeastern United States mature pine forests, the presence of the RCW impacts the operations of many Department of Defense (DoD) installations. A particular challenge in sustaining what are often small populations of RCW at these locations is the loss of genetic variation due to genetic drift. The optimal method for mitigating such loss is through the artificial immigration, …


Evaluation Of The Mountain Wave Forecast Model's Stratospheric Turbulence Simulations, Mark S. Allen Mar 2003

Evaluation Of The Mountain Wave Forecast Model's Stratospheric Turbulence Simulations, Mark S. Allen

Theses and Dissertations

Stratospheric turbulence (Stratoturb) is a well-known hazard to aircraft in flight. Forecasting mountain waves, specifically the breaking of these waves, is necessary to accurately predict the presence of Stratoturb. The Air Force Weather Agency (AFWA) requested a product with the capability of forecasting Stratoturb at 30, 50, and 70 mb using model data currently available, To facilitate their request, the Mountain Wave Forecast Model (MWFM) was acquired from the Naval Research Laboratory. MWFM turbulence forecasts generated twice daily over East Asia, using the AVN and MM5 models for initialization, were compared to S' layer turbulence analyses from the Rawinsonde Observation …


Evaluating The Performance Of Multiple Classifier Systems: A Matrix Algebra Representation Of Boolean Fusion Rules, Justin M. Hill Mar 2003

Evaluating The Performance Of Multiple Classifier Systems: A Matrix Algebra Representation Of Boolean Fusion Rules, Justin M. Hill

Theses and Dissertations

Given a finite collection of classifiers one might wish to combine, or fuse, the classifiers in hopes that the multiple classifier system (MCS) will perform better than the individuals. One method of fusing classifiers is to combine their final decision using Boolean rules (e.g., a logical OR, AND, or a majority vote of the classifiers in the system). An established method for evaluating a classifier is measuring some aspect of its Receiver Operating Characteristic (ROC) curve, which graphs the trade-off between the conditional probabilities of detection and false alarm. This work presents a unique method of estimating the performance of …


Active Processor Scheduling Using Evolution Algorithms, David J. Caswell Dec 2002

Active Processor Scheduling Using Evolution Algorithms, David J. Caswell

Theses and Dissertations

The allocation of processes to processors has long been of interest to engineers. The processor allocation problem considered here assigns multiple applications onto a computing system. With this algorithm researchers could more efficiently examine real-time sensor data like that used by United States Air Force digital signal processing efforts or real-time aerosol hazard detection as examined by the Department of Homeland Security. Different choices for the design of a load balancing algorithm are examined in both the problem and algorithm domains. Evolutionary algorithms are used to find near-optimal solutions. These algorithms incorporate multiobjective coevolutionary and parallel principles to create an …


Power Scaling Feasibility Of Chromium-Doped Ii-Vi Laser Sources And The Demonstration Of A Chromium-Doped Zinc Selenide Face-Cooled Disk Laser, Jason B. Mckay Dec 2002

Power Scaling Feasibility Of Chromium-Doped Ii-Vi Laser Sources And The Demonstration Of A Chromium-Doped Zinc Selenide Face-Cooled Disk Laser, Jason B. Mckay

Theses and Dissertations

Tunable lasers in the 2-4 µm wavelength range are needed for Air Force sensor applications. Chromium-doped II-VI materials are a promising class of laser material for tunable operation in this wavelength range, but until recently had not produced enough output power to meet application requirements. This dissertation investigates Cr2+:II-VI material properties and potential laser designs, then experimentally demonstrates and analyzes the performance of a Cr2+:ZnSe disk laser design that can produce sufficient output power. Cr2+:II-VI laser materials are found to be susceptible to overheating and thermal lensing, but are otherwise satisfactory laser materials. The …


Finite Extinction Time For Non-Linear Absorption-Diffusion Equations, Jacob B. Goldberg Sep 2002

Finite Extinction Time For Non-Linear Absorption-Diffusion Equations, Jacob B. Goldberg

Theses and Dissertations

In this thesis, we develop a numerical method in order to approximate the solutions of one-dimensional, non-linear absorption-diffusion equations. We test our method for accuracy against a linear diffusion equation with a solution that can be written in closed form. We then test various types of diffusion and absorption terms to determine which ones produce extinction in finite time. We also develop a numerical method to computationally solve diffusion-free equations. We compare the numerical solutions of the one-dimensional, non-linear absorption-diffusion equation and the diffusion-free equation and we find that for the cases tested, the numerical absorption-diffusion solutions are always less …


Adaptive Harmonic Balance Method For Unsteady, Nonlinear, One-Dimensional Periodic Flows, Raymond C. Maple Sep 2002

Adaptive Harmonic Balance Method For Unsteady, Nonlinear, One-Dimensional Periodic Flows, Raymond C. Maple

Theses and Dissertations

A new adaptive split-domain harmonic balance computational fluid dynamics (CFD) method is developed to solve highly nonlinear time-periodic flows such as those found in turbomachinery. The basic harmonic balance CFD method transforms an unsteady time-periodic problem into a steady-state problem by assuming a solution in the form of a Fourier series in time. The new method employs a unique multi-domain split-operator solution technique to remove a large-series stability restriction present in previous harmonic balance CFD approaches. In addition, the new method adapts the frequency content to the flow, starting with a small number of Fourier frequencies and augmenting the frequency …


High Energy Laser Pointing Through Extended Turbulence, Jason A. Tellez Sep 2002

High Energy Laser Pointing Through Extended Turbulence, Jason A. Tellez

Theses and Dissertations

The airborne laser (ABL) uses adaptive optics to compensate the atmospheric turbulence between the ABL and the target. The primary purpose of this compensation is to increase the energy density of the energy laser at the target. However, the specifics of the engagement scenario require the tracking point of reference and the adaptive optics point of reference to be located at different points on the target. This research considers the effects of tracking a target in one direction while compensating for atmospheric turbulence in a different directions. The target references used are a point source and a rectangle, while a …


Comparing Clustering Algorithms For Use With Genomic And Proteomic Data, Rebecca A. Olson Sep 2002

Comparing Clustering Algorithms For Use With Genomic And Proteomic Data, Rebecca A. Olson

Theses and Dissertations

The Human Genome Project and related projects have resulted in the development of a number of new experimental and analytic tools for use in genomic and proteomic research. In the area of toxicogenomics, researchers are concerned with how genes react to exposure to certain chemicals. The United States Air Force is interested in the effect of exposure to mission-essential chemicals. Although military personnel may come into contact with chemicals such as hydrazine, risk assessment is usually very limited. On the genomic level, risk assessment is a multi-stop and multi-disciplinary process. The process begins with an experiment that exposes cells to …


Analysis For Cooperative Behavior Effectiveness Of Autonomous Wide Area Search Munitions, Sang M. Park Aug 2002

Analysis For Cooperative Behavior Effectiveness Of Autonomous Wide Area Search Munitions, Sang M. Park

Theses and Dissertations

The purpose of this study is to investigate how a simulation model can accurately represent the performance of the autonomous wide area search munitions, and to find the effectiveness of the cooperative behavior on the autonomous munitions. Though it does not provide a practical solution for the development of the autonomous wide area search munitions, this research will show some meaningful allocations of the munitions tasks that are applicable to the development of the autonomous munitions. For the first phase, this thesis presents how accurately a simplified simulation model can represent a proposed weapon system by comparing the simulation results …


Visual Execution Analysis For Multiagent Systems, Chong Kil Aug 2002

Visual Execution Analysis For Multiagent Systems, Chong Kil

Theses and Dissertations

Multiagent systems have become increasingly important in developing complex software systems. Multiagent systems introduce collective intelligence and provide benefits such as flexibility, scalability, decentralization, and increased reliability. A software agent is a high-level software abstraction that is capable of performing given tasks in an environment without human intervention. Although multiagent systems provide a convenient and powerful way to organize complex software systems, developing such system is very complicated. To help manage this complexity this research develops a methodology and technique for analyzing, monitoring and troubleshooting multiagent systems execution. This is accomplished by visualizing a multiagent system at multiple levels of …


Efficient And Accurate Computation Of Non-Negative Anisotropic Group Scattering Cross Sections For Discrete Ordinates And Monte Carlo Radiation Transport, David W. Gerts Jul 2002

Efficient And Accurate Computation Of Non-Negative Anisotropic Group Scattering Cross Sections For Discrete Ordinates And Monte Carlo Radiation Transport, David W. Gerts

Theses and Dissertations

A new method for approximating anisotropic, multi-group scatter cross sections for use in discretized and Monte Carlo multi-group neutron transport is presented. The new method eliminates unphysical artifacts such as negative group scatter cross sections and falsely positive cross sections. Additionally, when combined with the discrete elements angular quadrature method, the new cross sections eliminate the lack of angular support in the discrete ordinates quadrature method. The new method generates piecewise-average group-to-group scatter cross sections. The accuracy and efficiency for calculating the discrete elements cross sections has improved by many orders of magnitude compared to DelGrande and Mathews previous implementation. …


Performance Analysis Of A Secure Ieee 802.11b Wireless Network Incorporating Personal Digital Assistants, John L. Camp Jun 2002

Performance Analysis Of A Secure Ieee 802.11b Wireless Network Incorporating Personal Digital Assistants, John L. Camp

Theses and Dissertations

Research results of this thesis indicate very poor performance of a Wireless Local Area Network (WLAN) utilizing PDAs. Network throughput is adversely effected most by VPN implementation and slightly by increased file size. The client distance factor has virtually no effect on the throughput. The impact of each of these factor levels is small when compared to the magnitude of the overall mean throughput (<6%). The average network throughput with the PDA client is much lower than expected (=11,500 bps). This is attributed to several factors with degradation primarily resulting from limitations of the PDA hardware and O/S. Because of the low throughput values achieved (regardless if VPN is on or off), an operational WLAN with PDAs (as tested) is not feasible. Operational use of the network tested would require an in-depth analysis of the type of network traffic and performance required to maintain functionality. To deploy such a system, custom designed Winsock controls would need to be implemented to minimize limitations imposed by the PDA. As PDA technology continues to develop, future hardware and O/S functionality may provide a more robust platform for network communications. The battery life of the PDA and packet battery combination is observed to be about 164 minutes with additional jackets adding about 90 minutes each.


Long Range Forecast Possibilities For X-Band Radar Construction On Shemya, Brian K. Schroeder May 2002

Long Range Forecast Possibilities For X-Band Radar Construction On Shemya, Brian K. Schroeder

Theses and Dissertations

Current moisture initialization sources lack the spatial and temporal resolution required for mesoscale moisture forecast accuracy critical for military operations. The Global Positioning System (GPS) satellite constellation provides an opportunity to extract accurate moisture observations based on the refraction of the GPS signal through the troposphere. GPS-derived precipitable water (PW) from two different research areas was independently compared with the Air Force Weather Agency s (AFWA's) MM5 PW model output. Results were concurrent with similar studies comparing GPS-derived PW with numerical weather models. The mean correlation in CONUS was 92.5%, while in Alaska it was 72.8%. Mean model biases were …


Quantification Of The Effects Of Data Denial And Limitation In Mm5 Initialization On Forecast Accuracy, Robert W. Evans Mar 2002

Quantification Of The Effects Of Data Denial And Limitation In Mm5 Initialization On Forecast Accuracy, Robert W. Evans

Theses and Dissertations

The current hub-and-spoke network in the European Theater is made up of locations built and organized around a Cold War threat. The threat of large-scale attrition warfare seems to have passed, and the threat of multiple, smaller scale contingencies has placed greater demands on the US military's ability to transport equipment and personnel to multiple locations simultaneously. This research effort utilizes a Multiple Objective Linear Programming (MOLP) model to analyze optimal hub locations in USEUCOM. The model used to analyze the network was developed in Microsoft Excel and followed MOLP techniques to determine the trade-offs between the two constructs of …


The Horizontal Extent Of Lightning Based On Altitude And Atmospheric Temperature, David R. Vollmer Mar 2002

The Horizontal Extent Of Lightning Based On Altitude And Atmospheric Temperature, David R. Vollmer

Theses and Dissertations

Due to multiple factors, including an increase in military operations tempo and the improved resolution of meteorological models, demand for access to customized aviation weather products has increased exponentially. This has given rise to a need for a multi-purpose interactive aviation weather product generation software solution. This software solution must be platform-independent, multiple data source access configurable, robust, extensible or upgradeable, user-friendly, and an improvement over current visualization applications used in the operational military aviation weather community. This thesis determines whether Unidata MetApps meets these criteria. A software reuse and component-based engineering approach was taken in this thesis. Two experimental …


Gps-Derived Precipitable Water Compared With The Air Force Weather Agency's Mm5 Model Output, Patricia A. Vollmer Mar 2002

Gps-Derived Precipitable Water Compared With The Air Force Weather Agency's Mm5 Model Output, Patricia A. Vollmer

Theses and Dissertations

Lightning poses a threat to aircraft in flight. To mitigate this threat, the U.S. Air Force requested a study of lightning distances. Three-Dimensional lightning data were examined for this study, spanning 1 March 1997 to 31 May 2001 and obtained from the Lightning Detection and Ranging System (LDAR) at the Kennedy Space Center, FL. The LDAR data points were first grouped into lightning flashes and branches using spatial and temporal criteria. Rawinsonde data were vertically interpolated to determine the temperature at the flash source point and each branch end point. The horizontal distance from flash sources to branch end was …


Suitability Of Unidata Metapps For Incorporation In Platform-Independent User-Customized Aviation Weather Products Generation Software, Harmen P. Visser Mar 2002

Suitability Of Unidata Metapps For Incorporation In Platform-Independent User-Customized Aviation Weather Products Generation Software, Harmen P. Visser

Theses and Dissertations

The Air Force Combat Climatology Center (AFCCC) is tasked to provide long-range seasonal forecasts for worldwide locations. Currently, the best long-range temperature forecasts the weather community has are the climatological standard normals. This study creates a stepping-stone into the solution of long-range forecasting by finding a process to predict temperatures better than those using climatological standard normals or simple frequency distributions of occurrences. Northern Hemispheric teleconnection indices and the standardized Southern Oscillation index are statistically compared to three-month summed Heating Degree Days (HDDs) and Cooling Degree Days (CDDs) at 14 U.S. locations. First, linear regression was accomplished. The results showed …


Using An Inductive Learning Algorithm To Improve Antibody Generation In A Single Packet Computer Defense Immune System, Russell J. Aycock Mar 2002

Using An Inductive Learning Algorithm To Improve Antibody Generation In A Single Packet Computer Defense Immune System, Russell J. Aycock

Theses and Dissertations

Coherent optical sources in the mid-infrared region (mid-IR) are important fundamental tools for infrared countermeasures and battlefield remote sensing. Nonlinear optical effects can be applied to convert existing near-IR laser sources to radiate in the mid-IR. This research focused on achieving such a conversion with a quasi-phase matched optical parametric oscillators using orientation-patterned gallium arsenide (OPGaAs), a material that can be quasi-phased matched by periodically reversing the crystal structure during the epitaxial growth process. Although non-linear optical conversion was not ultimately achieved during this research, many valuable lessons were learned from working with this material. This thesis reviews the theory …


An Anion Characterization Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Bradley M. Bugg Mar 2002

An Anion Characterization Of A Constructed Wetland Used For Chlorinated Ethene Remediation, Bradley M. Bugg

Theses and Dissertations

Chlorinated ethenes physical properties as well as its ubiquitous state at DOD installations makes it a priority for innovative remediation efforts. Current techniques are expensive and time consuming to maintain. Constructed wetlands suggest an inexpensive and operational alternative to conventional technologies. Sub-surface flow wetlands provide the anaerobic zones necessary to reduce the recalcitrant chlorinated solvents prior to anaerobic or aerobic mineralization of its daughter products. A vertical flow cell to include sequential sedimentary layers of two hydric soil lifts and a mix of hydric soil and woody compost was the subject of this investigation. This study focused on the statistical …