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Articles 3061 - 3090 of 5606
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Applying Automated Theorem Proving To Computer Security, Kelly K. Mcelroy
Applying Automated Theorem Proving To Computer Security, Kelly K. Mcelroy
Theses and Dissertations
While more and more data is stored and accessed electronically, better access control methods need to be implemented for computer security. Formal modelling and analysis have been successfully used in certain areas of computer systems, such as verifying the security properties of cryptographic and authentication protocols. However, formal models for computer systems in cyberspace, like networks, have hardly advanced. A highly regarded graduate textbook cites the Take-Grant model created in 1977 as one of the \current" examples of security modelling and analysis techniques. This model is rarely used in practice though. This research implements the Take-Grant Protection model's four de …
Exploitation Of Self Organization In Uav Swarms For Optimization In Combat Environments, Dustin J. Nowak
Exploitation Of Self Organization In Uav Swarms For Optimization In Combat Environments, Dustin J. Nowak
Theses and Dissertations
This investigation focuses primarily on the development of effective target engagement for unmanned aerial vehicle (UAV) swarms using autonomous self-organized cooperative control. This development required the design of a new abstract UAV swarm control model which flows from an abstract Markov structure, a Partially Observable Markov Decision Process. Self-organization features, bio-inspired attack concepts, evolutionary computation (multi-objective genetic algorithms, differential evolution), and feedback from environmental awareness are instantiated within this model. The associated decomposition technique focuses on the iterative deconstruction of the problem domain state and dynamically building-up of self organizational rules as related to the problem domain environment. Resulting emergent …
Conceptual Study Of Rotary-Wing Microrobotics, Kelson D. Chabak
Conceptual Study Of Rotary-Wing Microrobotics, Kelson D. Chabak
Theses and Dissertations
This thesis presents a novel rotary-wing micro-electro-mechanical systems (MEMS) robot design. Two MEMS wing designs were designed, fabricated and tested including one that possesses features conducive to insect level aerodynamics. Two methods for fabricating an angled wing were also attempted with photoresist and CrystalBond™ to create an angle of attack. One particular design consisted of the wing designs mounted on a gear which are driven by MEMS actuators. MEMS comb drive actuators were analyzed, simulated and tested as a feasible drive system. The comb drive resonators were also designed orthogonally which successfully rotated a gear without wings. With wings attached …
Collision Avoidance For Uavs Using Optic Flow Measurement With Line Of Sight Rate Equalization And Looming, Paul J. Shelnutt
Collision Avoidance For Uavs Using Optic Flow Measurement With Line Of Sight Rate Equalization And Looming, Paul J. Shelnutt
Theses and Dissertations
A series of simplified scenarios is investigated whereby an optical flow balancing guidance law is used to avoid obstacles by steering an air vehicle between fixed objects/obstacles. These obstacles are registered as specific points that can be representative of features in a scene. The obstacles appear in the field of view of a single forward looking camera. First a 2-D analysis is presented where the rate of the line of sight from the vehicle to each of the obstacles to be avoided is measured. The analysis proceeds by initially using no field of view (FOV) limitations, then applying FOV restrictions, …
2007 Annual Report Of The Graduate School Of Engineering And Management, Air Force Institute Of Technology, Office Of Research And Sponsored Programs, Graduate School Of Engineering And Management, Afit
2007 Annual Report Of The Graduate School Of Engineering And Management, Air Force Institute Of Technology, Office Of Research And Sponsored Programs, Graduate School Of Engineering And Management, Afit
AFIT Documents
The Graduate School's Annual Report highlights research focus areas, new academic programs, faculty accomplishments and news, and provides top-level sponsor-funded research data and information.
Multi-Class Classification Fusion Using Boosting For Identifying Steganography Methods, Benjamin M. Rodriguez, Gilbert L. Peterson
Multi-Class Classification Fusion Using Boosting For Identifying Steganography Methods, Benjamin M. Rodriguez, Gilbert L. Peterson
Faculty Publications
No abstract provided.
Cyber Flag: A Realistic Cyberspace Training Construct, Andrew P. Hansen
Cyber Flag: A Realistic Cyberspace Training Construct, Andrew P. Hansen
Theses and Dissertations
As is well understood, the rapidly unfolding challenges of cyberspace is a fundamental warfare paradigm shift revolutionizing the way future wars will be fought and won. A significant test for the Air Force (indeed any organization with a credible presence in cyberspace) will be providing a realistic training environment that fully meets this challenge. Why create another Flag level exercise? Realistic training (that which is effective, comprehensive and coordinated) is crucial to success in time of war. Red Flag provides dominant training within the air domain and now with the evolution of cyberspace, a comprehensive training environment is necessary to …
Entire Blow-Up Solutions Of Semilinear Elliptic Equations And Systems, Jesse D. Peterson
Entire Blow-Up Solutions Of Semilinear Elliptic Equations And Systems, Jesse D. Peterson
Theses and Dissertations
We examine two problems concerning semilinear elliptic equations. We consider single equations of the form Δu = p(x)uα + q(x)uβ for 0 <α ≤ β ≤1 and systems Δu = p(| x |) f (v), Δv = q(| x |)g(u) , both in Euclidean n -space, n ≥ 3 . These types of problems arise in steady state diffusion, the electric potential of some bodies, subsonic motion of gases, and control theory. For the single equation case, we present sufficient conditions on p and q to …
Risk-Based Comparison Of Classification Systems, Seth B. Wagenman
Risk-Based Comparison Of Classification Systems, Seth B. Wagenman
Theses and Dissertations
Performance measures for families of classification system families that rely upon the analysis of receiver operating characteristics (ROCs), such as area under the ROC curve (AUC), often fail to fully address the issue of risk, especially for classification systems involving more than two classes. For the general case, we denote matrices of class prevalences, costs, and class-conditional probabilities, and assume costs are subjectively fixed, acceptable estimates for expected values of class-conditional probabilities exist, and mutual independence between a variable in one such matrix and those of any other matrix. The ROC Risk Functional (RRF), valid for any finite number of …
Statistical Removal Of Shadow For Applications To Gait Recognition, Brian D. Hockersmith
Statistical Removal Of Shadow For Applications To Gait Recognition, Brian D. Hockersmith
Theses and Dissertations
The purpose of this thesis is to mathematically remove the shadow of an individual on video. The removal of the shadow will aid in the rendering of higher quality binary silhouettes than previously allowed. These silhouettes will allow researchers studying gait recognition to work with silhouettes unhindered by unrelated data. The thesis begins with the analysis of videos of solid colored backgrounds. A formulation of the effect of shadow on specified colors will aid in the derivation of a hypothesis test to remove an individual’s shadow. Video of an individual walking normally, perpendicular to the camera will be utilized to …
Predicting Cost And Schedule Growth For Military And Civil Space Systems, Christina F. Rusnock
Predicting Cost And Schedule Growth For Military And Civil Space Systems, Christina F. Rusnock
Theses and Dissertations
Military and civil space acquisitions have received much criticism for their inability to produce realistic cost and schedule estimates. This research seeks to provide space systems cost estimators with a forecasting tool for space system cost and schedule growth by identifying factors contributing to growth, quantifying the relative impact of these factors, and establishing a set of models for predicting space system cost and schedule growth. The analysis considers data from both Department of Defense (DoD) and National Aeronautics and Space Administration (NASA) space programs. The DoD dataset includes 21 space programs that submitted developmental Selected Acquisition Reports between 1969 …
Velocity Estimate Following Air Data System Failure, Scott A. Mclaren
Velocity Estimate Following Air Data System Failure, Scott A. Mclaren
Theses and Dissertations
Modern high performance aircraft can provide amazing performance due in part to their advanced flight control systems that require gain scheduling to provide optimum performance over a huge flight envelope. In modern fighter aircraft, this gain scheduling is a function of airspeed, and almost all of the research involving aircraft gain scheduling assumes aircraft airspeed to be a known quantity. The purpose of this research was to investigate a method of determining an aircraft’s airspeed in the event of total air data system failure. The process began by combining known aircraft information following an air data system failure to determine …
Real-Time Navigation And Flight Path Generation For Tracking Stop-And-Go Targets With Miniature Air Vehicles, Nate A. Terning
Real-Time Navigation And Flight Path Generation For Tracking Stop-And-Go Targets With Miniature Air Vehicles, Nate A. Terning
Theses and Dissertations
This research effort focuses on using a heuristic approach to determine the optimal flight path required to put an Unmanned Aircraft System’s (UAS) sensor on a moving target in the presence of a constant wind field. This thesis builds on past work using dynamic optimization techniques to calculate minimum time to target. The computationally intensive dynamic optimization routines in their current form take a prohibitive amount of time to calculate and ultimately result in erroneous flight path predictions due to inherent execution time latencies. Therefore an iterative, suboptimal heuristic approach was explored to mitigate excessive calculation times and ultimately yield …
Space Based Satellite Tracking And Characterization Utilizing Non-Imaging Passive Sensors, Bradley R. Townsend
Space Based Satellite Tracking And Characterization Utilizing Non-Imaging Passive Sensors, Bradley R. Townsend
Theses and Dissertations
A technique is developed to determine the orbit of a sunlight illuminated satellite passing through the field-of-view of a sensor platform in a Highly Elliptical Orbit (HEO) and Geosynchronous orbit (GEO). The technique develops two different methods of initial orbit determination. The first relies on the Gauss initial orbit determination method to develop an estimate of the state from angular data. The second method relies on positional data of the target relative to the Earth’s background to determine an estimate of the state. These estimates are then refined in a non-linear least squares routine. This estimate of the state is …
Production And Characterization Of Femtosecond-Laser-Induced Air Plasma, David R. Armbruster
Production And Characterization Of Femtosecond-Laser-Induced Air Plasma, David R. Armbruster
Theses and Dissertations
The purpose of this research was to produce, characterize, and optimize laser induced air plasma as a preliminary step in using the plasma as a source of terahertz radiation. An 800 nanometer, 50 femtosecond, 0.75 Watt, pulsed Ti:Sapphire laser system was used as the source infrared beam. A beam expander was used to expand the beam to a diameter of approximately 6.5 mm, and the beam was focused through a 25 mm focal length achromatic lens to produce laser-induced plasma in ambient air. A 40 kHz ultrasonic transducer was used to detect the plasma. A second harmonic generation crystal was …
Ultrafast Spectroscopy Of Mid-Infrared Semiconductors Using The Signal And Idler Beams Of A Synchronous Optical Parametric Oscillator, Richard M. Derbis
Ultrafast Spectroscopy Of Mid-Infrared Semiconductors Using The Signal And Idler Beams Of A Synchronous Optical Parametric Oscillator, Richard M. Derbis
Theses and Dissertations
Mid-Wave Infrared (MWIR) semiconductors are of use to the Air Force for several applications. Ultrafast spectroscopy can be used to better quantify the effectiveness of semiconductor opto-electronic devices. The objective of this thesis was to improve the procedure for taking ultrafast, time-resolved measurements of photoluminescence from MWIR semiconductors. Previous work has used a mode-locked titanium sapphire (Ti:Saph) laser to excite the semiconductor sample and to upconvert the photoluminescence from the semiconductor. Work completed in this thesis improved on the techniques developed during previous work. A synchronous Optical Parameter Oscillator (OPO) will be used to convert the Ti:Saph laser (0.830 µm) …
Measuring Dispersion In Laser Cavity Mirrors Using White-Light Interferometry, Allison S. Goodspeed
Measuring Dispersion In Laser Cavity Mirrors Using White-Light Interferometry, Allison S. Goodspeed
Theses and Dissertations
Terahertz radiation is an emerging field that has far reaching applications. There is a need for portable and affordable terahertz sources that may be used for detection of structural weaknesses in aerospace composites. One possibility for terahertz generation is a femtosecond Cr:LiSAF laser. However, controlling intracavity dispersion is necessary in order to get the ultrashort pulses needed to generate terahertz radiation. This research measures dispersion of the chirped femtosecond intracavity mirrors by employing white-light interferometry and explains the theory behind the curve-fitting process used to calculate dispersion. To compensate for the narrow reflectivity band of the mirrors, a CaF2 …
Nonmechanical Multizoom Telescope Design Using A Liquid Crystal Spatial Light Modulator And Focus-Correction Algorithm, Eric W. Thompson
Nonmechanical Multizoom Telescope Design Using A Liquid Crystal Spatial Light Modulator And Focus-Correction Algorithm, Eric W. Thompson
Theses and Dissertations
Theoretical development and design of a compact nonmechanical multi-zoom telescope system is presented. A liquid crystal spatial light modulator (LC SLM) enables selection of four separate beam paths without the use of moving parts. Each path incurs a different focus aberration in the image plane that can be deconvolved with postprocessing to yield four possible corrected magnification options. To increase flexibility, each region has a 40-wave subrange of focus. Optical zooms of up to 10 times magnification are feasible and are limited only by system noise and signal to noise ratio. Elimination of moving parts for focus could prove beneficial …
Digital Signal Processing Leveraged For Intrusion Detection, Theodore J. Erickson
Digital Signal Processing Leveraged For Intrusion Detection, Theodore J. Erickson
Theses and Dissertations
This thesis describes the development and evaluation of a novel system called the Network Attack Characterization Tool (NACT). The NACT employs digital signal processing to detect network intrusions, by exploiting the Lomb-Scargle periodogram method to obtain a spectrum for sampled network traffic. The Lomb-Scargle method for generating a periodogram allows for the processing of unevenly sampled network data. This method for determining a periodogram has not yet been used for intrusion detection. The spectrum is examined to determine if features exist above a significance level chosen by the user. These features are considered an attack, triggering an alarm. Two traffic …
Mission Impact Analysis Visualization For Enhanced Situational Awareness, Sean C. M. Carroll
Mission Impact Analysis Visualization For Enhanced Situational Awareness, Sean C. M. Carroll
Theses and Dissertations
This research effort examines the creation of mission impact analysis visualizations to enhance situational awareness. It focuses on using prefuse to create a visualization that allows the user to quickly understand the impact of the failure of any element needed directly or indirectly for a mission. The visualization correctly identifies the direct or indirect impact on physical requirements such as network links and servers as well as non-physical elements such as the generation of a report, or ability to perform a task. The visualization provides an overview of the situation, as well as including enhancements to allow for greater detail …
Dod Role For Securing United States Cyberspace, Jane J. Griffin
Dod Role For Securing United States Cyberspace, Jane J. Griffin
Theses and Dissertations
The cyber attacks on Estonia in late April and the early weeks of May 2007 significantly crippled the country, preventing it from performing banking, communications, news reporting, government transactions and command and control activities. Estonia is considered a “Wired Society”, much like the United States. Both countries rely on the cyberspace infrastructure economically and politically. Estonia sought assistance outside the country to recover from and to address the attacks. The cyber attacks on Estonia focused world-wide attention on the effects that cyberspace attacks could have on countries. If a cyber attack of national significance occurred against the United States, what …
Dynamic Protocol Reverse Engineering A Grammatical Inference Approach, Mark E. Deyoung
Dynamic Protocol Reverse Engineering A Grammatical Inference Approach, Mark E. Deyoung
Theses and Dissertations
Round trip engineering of software from source code and reverse engineering of software from binary files have both been extensively studied and the state-of-practice have documented tools and techniques. Forward engineering of protocols has also been extensively studied and there are firmly established techniques for generating correct protocols. While observation of protocol behavior for performance testing has been studied and techniques established, reverse engineering of protocol control flow from observations of protocol behavior has not received the same level of attention. State-of-practice in reverse engineering the control flow of computer network protocols is comprised of mostly ad hoc approaches. We …
Obfuscation Framework Based On Functionally Equivalent Combinatorial Logic Families, Moses C. James
Obfuscation Framework Based On Functionally Equivalent Combinatorial Logic Families, Moses C. James
Theses and Dissertations
This thesis aims to be a few building blocks in the bridge between theoretical and practical software obfuscation that researchers will one day construct. We provide a method for random uniform selection of circuits based on a functional signature and specific construction specifiers. Additionally, this thesis includes the first formal definition of an algorithm that performs only static analysis on a program; that is analysis that does not rely on the input and output behavior of the analyzed program. This is analogous to some techniques used in real-world software reverse engineering. Finally, this thesis uses the equivalent circuit library to …
An Investigation Into The Advantages, Mechanisms, And Developmental Challenges Of Scripted Mobile Routing, Boyeon Jang
An Investigation Into The Advantages, Mechanisms, And Developmental Challenges Of Scripted Mobile Routing, Boyeon Jang
Theses and Dissertations
Mobile Ad Hoc Network (MANET) routing protocols provide routing solutions in mobile wireless networks, without assuming any prior knowledge of topology nor any prediction of future topology. However, the resulting routes suffer from delay and consume precious bandwidth. Perfectly scripted routing could theoretically be optimal, (i.e., introduce no delay and cost no additional bandwidth), but would naturally be very fragile. This thesis explores a merging of these approaches, following a routing script if and when available, but reverting to a robust recovery approach otherwise. Script-Assisted Ad Hoc On-demand Distance Vector (S-AODV) routing protocol is designed to take advantage of prior …
A Novel Communications Protocol Using Geographic Routing For Swarming Uavs Performing A Search Mission, Robert L. Lidowski
A Novel Communications Protocol Using Geographic Routing For Swarming Uavs Performing A Search Mission, Robert L. Lidowski
Theses and Dissertations
This research develops the UAV Search Mission Protocol (USMP) for swarming UAVs and determines the protocol's effect on search mission performance. It is hypothesized that geographically routing USMP messages improves search performance by providing geography-dependent data to locations where it impacts search decisions. It is also proposed that the swarm can use data collected by the geographic routing protocol to accurately determine UAV locations and avoid sending explicit location updates. The hypothesis is tested by developing several USMP designs that are combined with the Greedy Perimeter Stateless Routing (GPSR) protocol and a search mission swarm logic into a single network …
Software Obfuscation With Symmetric Cryptography, Alan C. Lin
Software Obfuscation With Symmetric Cryptography, Alan C. Lin
Theses and Dissertations
Software protection is of great interest to commercial industry. Millions of dollars and years of research are invested in the development of proprietary algorithms used in software programs. A reverse engineer that successfully reverses another company‘s proprietary algorithms can develop a competing product to market in less time and with less money. The threat is even greater in military applications where adversarial reversers can use reverse engineering on unprotected military software to compromise capabilities on the field or develop their own capabilities with significantly less resources. Thus, it is vital to protect software, especially the software’s sensitive internal algorithms, from …
Algorithms For White-Box Obfuscation Using Randomized Subcircuit Selection And Replacement, Kenneth E. Norman
Algorithms For White-Box Obfuscation Using Randomized Subcircuit Selection And Replacement, Kenneth E. Norman
Theses and Dissertations
Software protection remains an active research area with the goal of preventing adversarial software exploitation such as reverse engineering, tampering, and piracy. Heuristic obfuscation techniques lack strong theoretical underpinnings while current theoretical research highlights the impossibility of creating general, efficient, and information theoretically secure obfuscators. In this research, we consider a bridge between these two worlds by examining obfuscators based on the Random Program Model (RPM). Such a model envisions the use of program encryption techniques which change the black-box (semantic) and white-box (structural) representations of underlying programs. In this thesis we explore the possibilities for white-box transformation. Under an …
Creating An Agent Based Framework To Maximize Information Utility, John M. Pecarina
Creating An Agent Based Framework To Maximize Information Utility, John M. Pecarina
Theses and Dissertations
With increased reliance on communications to conduct military operations, information centric network management becomes vital. A Defense department study of information management for net-centric operations lists the need for tools for information triage (based on relevance, priority, and quality) to counter information overload, semi-automated mechanisms for assessment of quality and relevance of information, and advances to enhance cognition and information understanding in the context of missions [30]. Maximizing information utility to match mission objectives is a complex problem that requires a comprehensive solution in information classification, in scheduling, in resource allocation, and in QoS support. Of these research areas, the …
Multi-Reference Frame Image Registration For Rotation, Translation, And Scale, Christopher S. Costello
Multi-Reference Frame Image Registration For Rotation, Translation, And Scale, Christopher S. Costello
Theses and Dissertations
This thesis investigates applications of multi-reference frame image registration for image sets with various translation, rotation, and scale combinations. It focuses on registration accuracy improvement over traditional pairwise registration, and also compares the quality of scene estimation from frame averaging. Three experiments are developed which use cross-correlation to estimate translation, the Radon transform to estimate translation and rotation, and the Fourier-Mellin transform to estimate translation, rotation, and scale. Results from applying multi-reference frame registration in these experiments show distinct improvements in both registration accuracy and quality of frame averaging compared to single-reference frame registration. Furthermore, it is shown that the …
Design And Optimization Of Broadband High Impedance Ground Planes (Higp) For Surface Mount Antennas, Murat Dogrul
Design And Optimization Of Broadband High Impedance Ground Planes (Higp) For Surface Mount Antennas, Murat Dogrul
Theses and Dissertations
Gain and bandwidth metrics of broad-band low-profile antennas severely deteriorate when they are placed conformally onto the conductive skins of air, sea, and ground platforms. This detrimental effect is primarily due to out-of-phase reflections from the conductive body interfering with the antenna’s self radiation. Furthermore, lateral waves launched by the antenna couple into the thin substrate placed between the antenna and the platform, giving rise to surface waves resulting in significant diffraction from the edges of the substrate. To remedy these two major mechanisms degrading antenna performance, high impedance ground planes (HIGP) were designed. HIGPs made of a 2-dimensional periodic …