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Electronic State Distributions Of Y Ba2Cu3O7-X Laser Ablated Plumes, Patrick D. Kee
Electronic State Distributions Of Y Ba2Cu3O7-X Laser Ablated Plumes, Patrick D. Kee
Theses and Dissertations
The application of spectral and imagery diagnostics to YBa2Cu3O7 (YBCO) laser-ablated plumes was systematically studied to determine their effectiveness for process control. Emission signatures were collected for plumes created by ablating bulk YBCO with a pulsed laser source. A KrF (λ=248 nm) laser source operating at 4-10 J/cm2 at a 4-10 Hz pulse repetition frequency was used to ablate a bulk YBCO target at O2 background pressures ranging from 50 to 400 mTorr. Emission spectra were collected over the 500 to 860 nm bandpass at distances from the target ranging from 31.4 to …
A Study Of The Irradiance-And-Temperature-Dependence Of Mid-Wave-Infrared (Mwir)Absorption In Indium Antimonide (Insb), John M. Callahan
A Study Of The Irradiance-And-Temperature-Dependence Of Mid-Wave-Infrared (Mwir)Absorption In Indium Antimonide (Insb), John M. Callahan
Theses and Dissertations
This work entails further investigation of the absorption of photons in indium antimonide (InSb). Previously work at the Air Force Institute of Technology (AFIT) attributed laser blooming effects in InSb focal plane arrays (FPA’s) to the Burstein-Moss effect. The contributing effect is from a decrease in the absorption of the InSb material, such that the transmitted optical energy scatters off the integrated circuitry beneath the InSb thin film back into the optical system. To evaluate this, irradiance-dependent laser-absorption experiments were performed on thinned, InSb wafers prior to their FPA fabrication. The samples were illuminated with a focused CO2 laser at …
Range Precision Of Ladar Systems, Steven E. Johnson
Range Precision Of Ladar Systems, Steven E. Johnson
Theses and Dissertations
A key application of Laser Detection and Ranging (LADAR) systems is measurement of range to a target. Many modern LADAR systems are capable of transmitting laser pulses that are less than a few nanoseconds in duration. These short-duration pulses provide excellent range precision. However, randomness in the detected laser signals places limits on the precision. The goal of this dissertation is to quantify the range precision limits of LADAR systems. The randomness in the time between photon arrivals, which is called shot noise, is discussed in depth. System-dependent noise sources such as dark current and detector gain variation are considered. …
A Confidence Paradigm For Classification Systems, Nathan J. Leap
A Confidence Paradigm For Classification Systems, Nathan J. Leap
Theses and Dissertations
There is no universally accepted methodology to determine how much confidence one should have in a classifier output. This research proposes a framework to determine the level of confidence in an indication from a classifier system where the output is or can be transformed into a posterior probability estimate. This is a theoretical framework that attempts to unite the viewpoints of the classification system developer (or engineer) and the classification system user (or war-fighter). The paradigm is based on the assumptions that the system confidence acts like, or can be modeled as a value and that indication confidence can be …
The Roc Curves Of Fused Independent Classification Systems, Michael B. Walsh
The Roc Curves Of Fused Independent Classification Systems, Michael B. Walsh
Theses and Dissertations
The need for optimal target detection arises in many different fields. Due to the complexity of many targets, it is thought that the combination of multiple classification systems, which can be tuned to several individual target attributes or features, might lead to more optimal target detection performance. The ROC curves of fused independent two-label classification systems may be generated by the mathematical combination of their ROC curves to achieve optimal classifier performance without the need to test every Boolean combination. The monotonic combination of two-label independent classification systems which assign labels to the same target types results in a lattice …
Combat Identification Using Multiple Tuav Swarm, Younin Kang
Combat Identification Using Multiple Tuav Swarm, Younin Kang
Theses and Dissertations
In modern warfare, Tactical Unmanned Aerial Vehicles (TUAVs) are rapidly taking on a leading role in traditional and non-traditional ISR, to include Automatic Target Recognition (ATR). However, additional advancements in processors and sensors on TUAVs are still needed before they can be widely employed as a primary source for positive identification in the Combat Identification (CID) process. Cost is a driving factor for operating an ATR system using multiple TUAVs. The cost of high quality sensors appropriate for a single TUAV can be significantly higher than less sophisticated sensors suitable for deployment on a group, or swarm, of coordinated TUAVs. …
Interoperability Measurement, Thomas C. Ford
Interoperability Measurement, Thomas C. Ford
Theses and Dissertations
This research presents an inaugural general method of measuring the collaborative and confrontational interoperability of a heterogeneous set of systems in the context of an operational process. The method is holistic, fundamental, flexible, and mathematical in nature and accommodates all types of systems and interoperations. The method relates the interoperability measurement to measures of operational effectiveness for confrontational operational processes. Extant leveling methods of describing interoperability are shown to be a special case of the more general method given in this research and the general interoperability measurement method is demonstrated through the presentation of coalition interoperability, suppression of enemy air …
A Secure Group Communication Architecture For Autonomous Unmanned Aerial Vehicles, Adrian N. Phillips, Barry E. Mullins, Richard Raines, Rusty O. Baldwin
A Secure Group Communication Architecture For Autonomous Unmanned Aerial Vehicles, Adrian N. Phillips, Barry E. Mullins, Richard Raines, Rusty O. Baldwin
Faculty Publications
This paper investigates the application of a secure group communication architecture to a swarm of autonomous unmanned aerial vehicles (UAVs). A multicast secure group communication architecture for the low earth orbit (LEO) satellite environment is evaluated to determine if it can be effectively adapted to a swarm of UAVs and provide secure, scalable, and efficient communications. The performance of the proposed security architecture is evaluated with two other commonly used architectures using a discrete event computer simulation developed using MATLAB. Performance is evaluated in terms of the scalability and efficiency of the group key distribution and management scheme when the …
Stimulated Brillouin Scattering Phase Conjugation In Fiber Optic Waveguides, Steven M. Massey
Stimulated Brillouin Scattering Phase Conjugation In Fiber Optic Waveguides, Steven M. Massey
Theses and Dissertations
The objective of this research effort was to demonstrate the path to continuous wave, coherent beam combination through stimulated Brillouin scattering phase conjugation in optical fiber. This work experimentally determined the fiber parameters necessary for phase conjugation in step-index optical fiber. Continuous wave phase conjugation using stimulated Brillouin scattering in step-index fibers was achieved for the first time with a fidelity of 0.8 and a threshold power of 16 W in a 15-m fiber with 0.13 NA. A fidelity of 0.8 was also achieved using 40 m of fiber with 0.06-NA and a threshold power of 15 W. The fidelity …
Statistical Methods For Polarimetric Imagery, Daniel A. Lemaster
Statistical Methods For Polarimetric Imagery, Daniel A. Lemaster
Theses and Dissertations
Estimation theory is applied to a physical model of incoherent polarized light to address problems in polarimetric image registration, restoration, and analysis for electro-optical imaging systems. In the image registration case, the Cramer-Rao lower bound on unbiased joint estimates of the registration parameters and the underlying scene is derived, simplified using matrix methods, and used to explain the behavior of multi-channel linear polarimetric imagers. In the image restoration case, a polarimetric maximum likelihood blind deconvolution algorithm is derived and tested using laboratory and simulated imagery. Finally, a principal components analysis is derived for polarization imaging systems. This analysis expands upon …
On Graph Isomorphism And The Pagerank Algorithm, Christopher J. Augeri
On Graph Isomorphism And The Pagerank Algorithm, Christopher J. Augeri
Theses and Dissertations
A graph is a key construct for expressing relationships among objects, such as the radio connectivity between nodes contained in an unmanned vehicle swarm. The study of such networks may include ranking nodes based on importance, for example, by applying the PageRank algorithm used in some search engines to order their query responses. The PageRank values correspond to a unique eigenvector typically computed by applying the power method, an iterative technique based on matrix multiplication. The first new result described herein is a lower bound on the execution time of the PageRank algorithm that is derived by applying standard assumptions …
Multi-Class Classification For Identifying Jpeg Steganography Embedding Methods, Benjamin M. Rodriguez Ii
Multi-Class Classification For Identifying Jpeg Steganography Embedding Methods, Benjamin M. Rodriguez Ii
Theses and Dissertations
Over 725 steganography tools are available over the Internet, each providing a method for covert transmission of secret messages. This research presents four steganalysis advancements that result in an algorithm that identifies the steganalysis tool used to embed a secret message in a JPEG image file. The algorithm includes feature generation, feature preprocessing, multi-class classification and classifier fusion. The first contribution is a new feature generation method which is based on the decomposition of discrete cosine transform (DCT) coefficients used in the JPEG image encoder. The generated features are better suited to identifying discrepancies in each area of the decomposed …
Metamodeling Techniques To Aid In The Aggregation Process Of Large Hierarchical Simulation Models, June F. D. Rodriguez
Metamodeling Techniques To Aid In The Aggregation Process Of Large Hierarchical Simulation Models, June F. D. Rodriguez
Theses and Dissertations
This research investigates how aggregation is currently conducted for simulation of large systems. The purpose is to examine how to achieve suitable aggregation in the simulation of large systems. More specifically, investigating how to accurately aggregate hierarchical lower-level (higher resolution) models into the next higher-level in order to reduce the complexity of the overall simulation model. The focus is on the exploration of the different aggregation techniques for hierarchical lower-level (higher resolution) models into the next higher-level. We develop aggregation procedures between two simulation levels (e.g., aggregation of engagement level models into a mission level model) to address how much …
Scaling Ant Colony Optimization With Hierarchical Reinforcement Learning Partitioning, Erik J. Dries, Gilbert L. Peterson
Scaling Ant Colony Optimization With Hierarchical Reinforcement Learning Partitioning, Erik J. Dries, Gilbert L. Peterson
Faculty Publications
This paper merges hierarchical reinforcement learning (HRL) with ant colony optimization (ACO) to produce a HRL ACO algorithm capable of generating solutions for large domains. This paper describes two specific implementations of the new algorithm: the first a modification to Dietterich’s MAXQ-Q HRL algorithm, the second a hierarchical ant colony system algorithm. These implementations generate faster results, with little to no significant change in the quality of solutions for the tested problem domains. The application of ACO to the MAXQ-Q algorithm replaces the reinforcement learning, Q-learning, with the modified ant colony optimization method, Ant-Q. This algorithm, MAXQ-AntQ, converges to solutions …
Material Perturbations To Enhance Performance Of The Theile Half-Width Leaky Mode Antenna, Jason A. Girard
Material Perturbations To Enhance Performance Of The Theile Half-Width Leaky Mode Antenna, Jason A. Girard
Theses and Dissertations
Microstrip traveling-wave antennas, often referred to as leaky-wave antennas, have been shown to radiate when the dominant or fundamental mode is suppressed and the first higher-order mode is excited. One such microstrip variation is the Thiele Half-Width (THW) antenna, which operates from 5.9 - 8.2 GHz for this research. Increasing the bandwidth over which the THW antenna radiates is desired, as is a fundamental understanding of the propagation characteristics over this region. This dissertation seeks to vary or perturb the material and physical properties of the THW antenna, including strip-width variations and modifications of the substrate layer, to achieve these …
Characterizing Effects And Benefits Of Beam Defocus On High Energy Laser Performance Under Thermal Blooming And Turbulence Conditions For Air-To-Ground Engagements, Scott N. Long
Theses and Dissertations
This dissertation makes contributions towards knowledge of optimizing of laser weapon performance when operating in the air-to-ground (ATG) regime in thermal blooming conditions. Wave optics modeling techniques were used to represent laser weapon performance in a high fidelity sense to allow progress to be made toward improving lower-fidelity scaling laws that can be used in systems level analysis which has need for better representations of thermal blooming. Chemical-oxygen iodine laser (COIL) based weapon systems that operate near the ground will experience thermal blooming due to atmospheric absorption if output power is sufficiently high. The thermal lens in the ATG case …
Developing Network Situational Awareness Through Visualization Of Fused Intrusion Detection System Alerts, Serafin A. Avitia V
Developing Network Situational Awareness Through Visualization Of Fused Intrusion Detection System Alerts, Serafin A. Avitia V
Theses and Dissertations
With networks increasing in physical size, bandwidth, traffic volume, and malicious activity, network analysts are experiencing greater difficulty in developing network situational awareness. Traditionally, network analysts have used Intrusion Detection Systems to gain awareness but this method is outdated when analysts are unable to process the alerts at the rate they are being generated. Analysts are unwittingly placing the computer assets they are charged to protect at risk when they are unable to detect these network attacks. This research effort examines the theory, application, and results of using visualizations of fused alert data to develop network situational awareness. The fused …
Hardware, Software And Data Analysis Techniques For Sram-Based Field Programmable Gate Array Circuits, Eugene B. Hockenberry
Hardware, Software And Data Analysis Techniques For Sram-Based Field Programmable Gate Array Circuits, Eugene B. Hockenberry
Theses and Dissertations
This work presents a built, tested, and demonstrated test structure that is low-cost, flexible, and re-usable for robust radiation experimentation, primarily to investigate memory, in this case SRAMs and SRAM-based FPGAs. The space environment can induce many kinds of failures due to radiation effects. These failures result in a loss of money, time, intelligence, and information. In order to evaluate technologies for potential failures, a detailed test methodology and associated structure are required. In this solution, an FPGA board was used as the controller platform, with multiple VHDL circuit controllers, data collection and reporting modules. The structure was demonstrated by …
A Secure And Efficient Communications Architecture For Global Information Grid Users Via Cooperating Space Assets, Victor P. Hubenko Jr.
A Secure And Efficient Communications Architecture For Global Information Grid Users Via Cooperating Space Assets, Victor P. Hubenko Jr.
Theses and Dissertations
With the Information Age in full and rapid development, users expect to have global, seamless, ubiquitous, secure, and efficient communications capable of providing access to real-time applications and collaboration. The United States Department of Defense’s (DoD) Network-Centric Enterprise Services initiative, along with the notion of pushing the “power to the edge,” aims to provide end-users with maximum situational awareness, a comprehensive view of the battlespace, all within a secure networking environment. Building from previous AFIT research efforts, this research developed a novel security framework architecture to address the lack of efficient and scalable secure multicasting in the low earth orbit …
Statistical Methods For Image Registration And Denoising, Matthew D. Sambora
Statistical Methods For Image Registration And Denoising, Matthew D. Sambora
Theses and Dissertations
This dissertation describes research into image processing techniques that enhance military operational and support activities. The research extends existing work on image registration by introducing a novel method that exploits local correlations to improve the performance of projection-based image registration algorithms. The dissertation also extends the bounds on image registration performance for both projection-based and full-frame image registration algorithms and extends the Barankin bound from the one-dimensional case to the problem of two-dimensional image registration. It is demonstrated that in some instances, the Cramer-Rao lower bound is an overly-optimistic predictor of image registration performance and that under some conditions, the …
An Analysis Of Botnet Vulnerabilities, Sean W. Hudson
An Analysis Of Botnet Vulnerabilities, Sean W. Hudson
Theses and Dissertations
Botnets are a significant threat to computer networks and data stored on networked computers. The ability to inhibit communication between servers controlling the botnet and individual hosts would be an effective countermeasure. The objective of this research was to find vulnerabilities in Unreal IRCd that could be used to shut down the server. Analysis revealed that Unreal IRCd is a very mature and stable IRC server and no significant vulnerabilities were found. While this research does not eliminate the possibility that a critical vulnerability is present in the Unreal IRCd software, none were identified during this effort.
Time-Frequency Analysis Of Terahertz Radar Signals For Rapit Heart And Breath Rate Detection, Melody L. Massar
Time-Frequency Analysis Of Terahertz Radar Signals For Rapit Heart And Breath Rate Detection, Melody L. Massar
Theses and Dissertations
We develop new time-frequency analytic techniques which facilitate the rapid detection of a person's heart and breath rates from the Doppler shift the movement of their body induces in a terahertz radar signal. In particular, the Doppler shift in the continuous radar return is proportional to the velocity of the person's body. Thus, a time-frequency analysis of the radar return will yield a velocity signal. This signal, in turn, may undergo a second time-frequency analysis to yield any periodic components of the velocity signal, which are often related to the heart and breath rates of the individual. One straightforward means …
Developing A Decision Model For Joint Improvised Explosive Device Defeat Organization (Jieddo) Proposal Selection, Lyle M. Dawley, Lenore A. Marentee, Alice Marie Long
Developing A Decision Model For Joint Improvised Explosive Device Defeat Organization (Jieddo) Proposal Selection, Lyle M. Dawley, Lenore A. Marentee, Alice Marie Long
Theses and Dissertations
This research uses decision analysis to develop a structured, repeatable and most importantly defensible decision model for the evaluation of proposed IED defeat solutions submitted to the Joint IED Defeat Organization (JIEDDO). Additive value models using Value-Focused Thinking (VFT) and the Analytic Hierarchy Process (AHP) are examined as possible methodologies. VFT is determined to be the "best fit" for JIEDDO's decision situation in which proposals are submitted continuously and must be scored independently of previous proposals. VFT is first used to determine desirable qualities in IED defeat options, and then to generate a hierarchal value model to evaluate these qualities …
Optimal Control Of Electrodynamic Tethers, Robert E. Stevens
Optimal Control Of Electrodynamic Tethers, Robert E. Stevens
Theses and Dissertations
Low thrust propulsion systems such as electrodynamic tethers offer a fuel-efficient means to maneuver satellites to new orbits, however they can only perform such maneuvers when they are continuously operated for a long time. Such long-term maneuvers occur over many orbits often rendering short time scale trajectory optimization methods ineffective. An approach to multi-revolution, long time scale optimal control of an electrodynamic tether is investigated for a tethered satellite system in Low Earth Orbit with atmospheric drag. Control is assumed to be periodic over several orbits since under the assumptions of a nearly circular orbit, periodic control yields the only …
Evaluation Of Nanocomposites As Lightweight Electronic Enclosures For Satellites' Applications, Benjamin T. Harder
Evaluation Of Nanocomposites As Lightweight Electronic Enclosures For Satellites' Applications, Benjamin T. Harder
Theses and Dissertations
The United States military is exploring the use of nanocomposite materials for satellite structural applications. Current composite spacecraft structures are nonconductive and must have expensive shielding materials applied in order to protect the spacecraft from catastrophic damage that can be caused by electromagnetic interference (EMI) and/or electrostatic discharge (ESD) which are characteristics of the space environment. Conductive nanocomposites are being developed for spacecraft structures that will provide ESD and EMI shielding protection without the need for expensive secondary shielding materials. This thesis studied one such material consisting of M55J/RS-3 composite combined with nickel nanostrands™. Four different configurations were tested for …
Mitigating Reversing Vulnerabilities In .Net Applications Using Virtualized Software Protection, Matthew A. Zimmerman
Mitigating Reversing Vulnerabilities In .Net Applications Using Virtualized Software Protection, Matthew A. Zimmerman
Theses and Dissertations
Protecting intellectual property contained in application source code and preventing tampering with application binaries are both major concerns for software developers. Simply by possessing an application binary, any user is able to attempt to reverse engineer valuable information or produce unanticipated execution results through tampering. As reverse engineering tools become more prevalent, and as the knowledge required to effectively use those tools decreases, applications come under increased attack from malicious users. Emerging development tools such as Microsoft's .NET Application Framework allow diverse source code composed of multiple programming languages to be integrated into a single application binary, but the potential …
Development Of A Night Vision Goggle Heads Up Display For Paratrooper Guidance, Fernando Ontiveros
Development Of A Night Vision Goggle Heads Up Display For Paratrooper Guidance, Fernando Ontiveros
Theses and Dissertations
This thesis provides the proof of concept for the development and implementation of a Global Positioning System (GPS) display via Night Vision Goggles (NVG) Heads-Up Display (HUD) for paratroopers. The system has been designed for soldiers who will be able to utilize the technology in the form of a processing system worn in an ammo pouch and displayed via NVG HUD as a tunnel in the sky. The tunnel in the sky display design is essentially a series of boxes displayed within the goggle's HUD leading the paratrooper to the desired Landing Zone (LZ). The algorithm developed receives GPS and …
Analyzing Individual Decision Making Versus Group Decision Making For Alternative Selection, Alper Gezeravci
Analyzing Individual Decision Making Versus Group Decision Making For Alternative Selection, Alper Gezeravci
Theses and Dissertations
Many "real world" decisions are made by groups. It is rare that the responsi- bility for a very important decision is given to a single decision maker with complete authority. Group decision making adds both advantages to the process as well as disadvantages. This research examines the question: "Are decisions made by groups really that much different from the decisions made by individuals in the group?" A specific case study involving the selection of the best primary training aircraft type for military pilot training is used to examine this question. Fifteen military pilots with various backgrounds and experience levels participate …
Optical Phase Unwrapping In The Presence Of Branch Points, Todd M. Venema, Jason D. Schmidt
Optical Phase Unwrapping In The Presence Of Branch Points, Todd M. Venema, Jason D. Schmidt
Faculty Publications
Strong turbulence causes phase discontinuities known as branch points in an optical field. These discontinuities complicate the phase unwrapping necessary to apply phase corrections onto a deformable mirror in an adaptive optics (AO) system. This paper proposes a non-optimal but effective and implementable phase unwrapping method for optical fields containing branch points. This method first applies a least-squares (LS) unwrapper to the field which isolates and unwraps the LS component of the field. Four modulo-2π-equivalent non-LS components are created by subtracting the LS component from the original field and then restricting the result to differing ranges. 2π phase jumps known …
Integrating Trust Into The Cybercraft Initiative Via The Trust Vectors Model, Michael Stevens, Paul D. Williams, Gilbert L. Peterson, Stuart H. Kurkowski
Integrating Trust Into The Cybercraft Initiative Via The Trust Vectors Model, Michael Stevens, Paul D. Williams, Gilbert L. Peterson, Stuart H. Kurkowski
Faculty Publications
This research supports the hypothesis that the Trust Vector model can be modified to fit the CyberCraft Initiative, and that there are limits to the utility of historical data. This research proposed some modifications and expansions to the Trust Model Vector, and identified areas for future research.