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Articles 1 - 30 of 37
Full-Text Articles in Engineering
A Linear Combination Of Heuristics Approach To Spatial Sampling Hyperspectral Data For Target Tracking, Barry R. Secrest
A Linear Combination Of Heuristics Approach To Spatial Sampling Hyperspectral Data For Target Tracking, Barry R. Secrest
Theses and Dissertations
Persistent surveillance of the battlespace results in better battlespace awareness which aids in obtaining air superiority, winning battles, and saving friendly lives. Although hyperspectral imagery (HSI) data has proven useful for discriminating targets, it presents many challenges as a useful tool in persistent surveillance. A new sensor under development has the potential of overcoming these challenges and transforming our persistent surveillance capability by providing HSI data for a limited number of pixels and grayscale video for the remainder. The challenge of exploiting this new sensor is determining where the HSI data in the sensor's field of view will be the …
Improving Range Estimation Of A 3d Flash Ladar Via Blind Deconvolution, Jason R. Mcmahon
Improving Range Estimation Of A 3d Flash Ladar Via Blind Deconvolution, Jason R. Mcmahon
Theses and Dissertations
The purpose of this research effort is to improve and characterize range estimation in a three-dimensional FLASH LAser Detection And Ranging (3D FLASH LADAR) by investigating spatial dimension blurring effects. The myriad of emerging applications for 3D FLASH LADAR both as primary and supplemental sensor necessitate superior performance including accurate range estimates. Along with range information, this sensor also provides an imaging or laser vision capability. Consequently, accurate range estimates would also greatly aid in image quality of a target or remote scene under interrogation. Unlike previous efforts, this research accounts for pixel coupling by defining the range image mathematical …
Determining The Index Of Refraction Of An Unknown Object Using Passive Polarimetric Imagery Degraded By Atmospheric Turbulence, Milo W. Hyde Iv
Determining The Index Of Refraction Of An Unknown Object Using Passive Polarimetric Imagery Degraded By Atmospheric Turbulence, Milo W. Hyde Iv
Theses and Dissertations
In this research, an algorithm is developed to estimate the index of refraction of an unknown object using passive polarimetric images degraded by atmospheric turbulence. The algorithm uses a variant of the maximum-likelihood blind-deconvolution algorithm developed by LeMaster and Cain to recover the true object (i.e., the first Stokes parameter), the degree of linear polarization, and the polarimetric-image point spread functions. Nonlinear least squares is then used to find the value of the complex index of refraction which best fits the theoretical degree of linear polarization, derived using a polarimetric bidirectional reflectance distribution function, to the turbulence-corrected degree of linear …
Applying Image Matching To Video Analysis, Adam J. Behring
Applying Image Matching To Video Analysis, Adam J. Behring
Theses and Dissertations
Dealing with the volume of multimedia collected on a daily basis for intelligence gathering and digital forensics investigations requires significant manual analysis. A component of this problem is that a video may be reanalyzed that has already been analyzed. Identifying duplicate video sequences is difficult due to differences in videos of varying quality and size. This research uses a kd-tree structure to increase image matching speed. Keypoints are generated and added to a kd-tree of a large dimensionality (128 dimensions). All of the keypoints for the set of images are used to construct a global kd-tree, which allows nearest neighbor …
Architectural Considerations For Single Operator Management Of Multiple Unmanned Aerial Vehicles, Gabriel T. Bugajski
Architectural Considerations For Single Operator Management Of Multiple Unmanned Aerial Vehicles, Gabriel T. Bugajski
Theses and Dissertations
Recently, small Unmanned Aircraft Systems (UAS) have become ubiquitous in military battlefield operations due to their intelligence collection capabilities. However, these unmanned systems consistently demonstrate limitations and shortfalls with respect to size, weight, range, line of sight and information management. The United States Air Force Unmanned Aircraft Systems Flight Plan 2009-2047 describes an action plan for improved UAS employment which calls out single operator, multi-vehicle mission configurations. This thesis analyzes the information architecture using future concepts of operations, such as biologically-inspired flocking mechanisms. The analysis and empirical results present insight into the engineering of single-operator multiple-vehicle architectures.
Attaining Realistic Simulations Of Mobile Ad-Hoc Networks, Derek J. Huber
Attaining Realistic Simulations Of Mobile Ad-Hoc Networks, Derek J. Huber
Theses and Dissertations
Mobile Ad-hoc Networks (MANET) are comprised of wireless systems that communicate without the assistance of centrally managed routers or base stations. MANET research and development has increased due to computing technologies offering smaller, faster, smarter, and more power efficient platforms to operate on. Largely the testing and evaluation of new and existing MANET protocols has resided in simulation environments. This is due in part to the complexities and expenses incurred when conducting real world tests. Many researchers have come to recognize that these current simulations tend to assume away critical components of the MANET domain. These assumptions are made either …
The Effect Of Synthetic Aperture Radar Image Resolution On Target Discrimination, John E. Mcgowan
The Effect Of Synthetic Aperture Radar Image Resolution On Target Discrimination, John E. Mcgowan
Theses and Dissertations
This research details the effect of spatial resolution on target discrimination in Synthetic Aperture Radar (SAR) images. Multiple SAR image chips containing targets and non-targets are used to test a baseline Automatic Target Recognition (ATR) system with reduced spatial resolution. Spatial resolution is reduced by lowering the pixel count or synthesizing a degraded image by filtering and reducing the pixel count. A two-parameter Constant False Alarm Rate (CFAR) detector is tested, and three feature sets, size, contrast, and texture, are used to train a linear classifier and to estimate probability density functions for the two classes. The results are scored …
Reputation-Based Trust For A Cooperative, Agent-Based Backup Protection Scheme For Power Networks, John F. Borowski
Reputation-Based Trust For A Cooperative, Agent-Based Backup Protection Scheme For Power Networks, John F. Borowski
Theses and Dissertations
This thesis research explores integrating a reputation-based trust mechanism with an agent-based backup protection system to improve the performance of traditional backup relay methods that are currently in use in power transmission systems. Integrating agent technology into relay protection schemes has been previously proposed to clear faults more rapidly and to add precision by enabling the use of adaptive protection methods. A distributed, cooperative trust system such as that used in peer-to-peer file sharing networks has the potential to add an additional layer of defense in a protection system designed to operate with greater autonomy. This trust component enables agents …
High Power Microwave (Hpm) And Ionizing Radiation Effects On Cmos Devices, Nicholas A. Estep
High Power Microwave (Hpm) And Ionizing Radiation Effects On Cmos Devices, Nicholas A. Estep
Theses and Dissertations
Integrated circuits (ICs) are inherently complicated and made worse by increasing transistor quantity and density. This trend potentially enhances concomitant effects of high energy radiation and local or impressed electromagnetic interference (EMI). The reduced margin for signal error may counter any gain in radiation hardness from smaller device dimensions. Isolated EMI and ionizing radiation studies on circuits have been conducted extensively over the past 30 years. However, little focus has been placed on the combined effects. To investigate the effect of combined EMI and ionizing radiation, two complementary metal oxide semiconductor (CMOS) inverter technologies (CD4069 and SN74AUC1G04) were analyzed for …
Changes To Electrical Conductivity In Irradiated Carbon-Nickel Nanocomposites, David F. Coy
Changes To Electrical Conductivity In Irradiated Carbon-Nickel Nanocomposites, David F. Coy
Theses and Dissertations
Pre and post irradiation resistivity and XAFS measurements have been conducted to examine the effects of 0.5 MeV electron irradiations on nickel-carbon composites. Results showed a decrease in surface resistivity in all sample types of 14-30% following irradiation with a total electron exposure of 4 x 10-16 cm-2. Results also showed a corresponding decrease in NiO content for the irradiated samples as compared to measurements of non-irradiated samples. Surface resistivity measurement capabilities were established and measurement techniques refined to produce repeatable results of sufficient precision to discern changes in resistivity for an exposure of 2 x 10 …
Scalable And Fault Tolerant Group Key Management, Nicholas A. Lupien
Scalable And Fault Tolerant Group Key Management, Nicholas A. Lupien
Theses and Dissertations
To address the group key management problem for modern networks this research proposes a lightweight group key management protocol with a gossip-based dissemination routine. Experiments show that by slightly increasing workload for the key update mechanism, this protocol is superior to currently available tree-based protocols with respect to reliability and fault tolerance, while remaining scalable to large groups. Java simulations show that the protocol efficiently distributes keys to large groups in the midst of up to 35 percent node failure rates. In addition, it eliminates the need for logical key hierarchy while preserving an overall reduction in rekey messages to …
Static And Dynamic Component Obfuscation On Reconfigurable Devices, Camdon R. Cady
Static And Dynamic Component Obfuscation On Reconfigurable Devices, Camdon R. Cady
Theses and Dissertations
Computing systems are used in virtually every aspect of our lives. Technology such as smart phones and electronically controlled subsystems in cars is becoming so commonly used that it is virtually ubiquitous. Sometimes, this technology can be exploited to perform functions that it was never intended to perform, or fail to provide information that it is supposed to protect. X-HIA was shown to be effective at identifying several circuit components in a significantly shorter time than previous identification methods. Instead of requiring a number of input/output pairings that grows factorially or exponentially as the circuit size grows, it requires only …
Investigating The Use Of Frequency Selective Surfaces In High Power Microwave Applications, Steven M. Pugh
Investigating The Use Of Frequency Selective Surfaces In High Power Microwave Applications, Steven M. Pugh
Theses and Dissertations
This thesis explores new territory with the theoretical investigation of the use of Frequency Selective Surfaces (FSS) in High Power Microwave (HPM) applications. Work was performed in a simulation environment where rectangular and ring-shaped FSS elements were evaluated. Incident electric field levels of 0.5MV/m were propagated toward the FSS in a plane wave that was perpendicular to the surface. Results show that the total electric field in the apertures of the FSS can reach more than 6MV/m. This necessitates the use of high strength dielectric materials surrounding the FSS to reduce the risk of electrical breakdown. It is shown that …
Improved Multispectral Skin Detection And Its Application To Search Space Reduction For Dismount Detection Based On Histograms Of Oriented Gradients, Adam L. Brooks
Theses and Dissertations
Due to the general shift from conventional warfare to terrorism and urban warfare by enemies of the United States in the late 20th Century, locating and tracking individuals of interest have become critically important. Dismount detection and tracking are vital to provide security and intelligence in both combat and homeland defense scenarios including base defense, combat search and rescue (CSAR), and border patrol. This thesis focuses on exploiting recent advances in skin detection research to reliably detect dismounts in a scene. To this end, a signal-plus-noise model is developed to map modeled skin spectra to the imaging response of an …
Effects Of Channel Mismatches On Beamforming And Signal Detection, Christopher I. Allen
Effects Of Channel Mismatches On Beamforming And Signal Detection, Christopher I. Allen
Theses and Dissertations
Tuner gain measurements of a multichannel receiver are reported. A linear regression model is used to characterize the gain, as a function of channel number, tuner set-on frequency, and intermediate frequency. Residual errors of this model are characterized by a t distribution. Very strong autocorrelation of tuner gain at various frequencies is noted. Tuner performance from one channel to the next is diverse; several defects at specific frequencies are noted. The Wilcoxon signed rank test is used to test normality of tuner gain among devices; normality is rejected. Antenna directivity and phase pattern measurements are also reported. An antenna element …
Frequency Diverse Array Radar: Signal Characterization And Measurement Accuracy, Steven H. Brady
Frequency Diverse Array Radar: Signal Characterization And Measurement Accuracy, Steven H. Brady
Theses and Dissertations
Radar systems provide an important remote sensing capability, and are crucial to the layered sensing vision; a concept of operation that aims to apply the right number of the right types of sensors, in the right places, at the right times for superior battle space situational awareness. The layered sensing vision poses a range of technical challenges, including radar, that are yet to be addressed. To address the radar-specific design challenges, the research community responded with waveform diversity; a relatively new field of study which aims reduce the cost of remote sensing while improving performance. Early work suggests that the …
Design Of A Monocular Multi-Spectral Skin Detection, Melanin Estimation, And False-Alarm Suppression System, Keith R. Peskosky
Design Of A Monocular Multi-Spectral Skin Detection, Melanin Estimation, And False-Alarm Suppression System, Keith R. Peskosky
Theses and Dissertations
A real-time skin detection, false-alarm reduction, and melanin estimation system is designed targeting search and rescue (SAR) with application to special operations for manhunting and human measurement and signatures intelligence. A mathematical model of the system is developed and used to determine how the physical system performs under illumination, target-to-sensor distance, and target-type scenarios. This aspect is important to the SAR community to gain an understanding of the deployability in different operating environments. A multi-spectral approach is developed and consists of two short-wave infrared cameras and two visible cameras. Through an optical chain of lenses, custom designed and fabricated dichroic …
Aiding Gps With Additional Satellite Navigation Services, Yasin A. Mutlu
Aiding Gps With Additional Satellite Navigation Services, Yasin A. Mutlu
Theses and Dissertations
In modern warfare navigation services are very important. GPS is currently providing service for accurate navigation, except in some areas, especially urban areas, where GPS signals cannot always be tracked by users. In these cases some additional navigation support could be provided by other global navigation satellite systems. If GPS is combined with other navigation systems than the navigation gap will be minor. In this thesis, the effect of combining GPS with other satellite navigation systems, specifically GLONASS, Galileo and Compass, is evaluated in terms of availability and position dilution of precision (PDOP) values. First, satellite constellations are simulated in …
Preliminary Electrical Designs For Ctex And Afit Satellite Ground Station, Arthur L. Morse
Preliminary Electrical Designs For Ctex And Afit Satellite Ground Station, Arthur L. Morse
Theses and Dissertations
This thesis outlines the design of the electrical components for the space-based ChromoTomography Experiment (CTEx). CTEx is the next step in the development of high-speed chromotomography at the Air Force Institute of Technology. The electrical design of the system is challenging due to the large amount of data that is acquired by the imager and the limited resources that is inherent with space-based systems. Additional complication to the design is the need to know the angle of a spinning prism that is in the field of view very precisely for each image. Without this precise measurement any scene that is …
Development And Demonstration Of A Field-Deployable Fast Chromotomographic Imager, Daniel C. O'Dell
Development And Demonstration Of A Field-Deployable Fast Chromotomographic Imager, Daniel C. O'Dell
Theses and Dissertations
A field deployable hyperspectral imager utilizing chromotomography (CT), with a direct vision prism (DVP) as the dispersive element, has been constructed at AFIT. This research is focused on the development and demonstration of the CT imager. An overview of hyperspectral imaging, chromotomography, a synopsis of reconstruction algorithms, and other CT instruments are given. The importance of component alignment, instrument calibration, and exact prism angular position data are discussed. A simplistic \shift and add" reconstruction algorithm was utilized for this research. Although limited in its ability to reconstruct a spatially and spectrally diverse scene, the algorithm was adequate for the testing …
Spectrally-Temporally Adapted Spectrally Modulated Spectrally Encoded (Smse) Waveform Design For Coexistent Cr-Based Sdr Applications, Eric C. Like
Theses and Dissertations
This work expands the applicability of the Spectrally Modulated, Spectrally Encoded (SMSE) framework by developing a waveform optimization process that enables intelligent waveform design. The resultant waveforms are capable of adapting to a spectrally diverse transmission channel while meeting coexistent constraints. SMSE waveform design is investigated with respect to two different forms of coexisting signal constraints, including those based on resultant interference levels and those based on resultant power spectrum shape. As demonstrated, the SMSE framework is well-suited for waveform optimization given its ability to allow independent design of spectral parameters. This utility is greatly enhanced when soft decision selection …
Multi-Objective Constraint Satisfaction For Mobile Robot Area Defense, Kenneth W. Mayo
Multi-Objective Constraint Satisfaction For Mobile Robot Area Defense, Kenneth W. Mayo
Theses and Dissertations
In developing multi-robot cooperative systems, there are often competing objectives that need to be met. For example in automating area defense systems, multiple robots must work together to explore the entire area, and maintain consistent communications to alert the other agents and ensure trust in the system. This research presents an algorithm that tasks robots to meet the two specific goals of exploration and communication maintenance in an uncoordinated environment reducing the need for a user to pre-balance the objectives. This multi-objective problem is defined as a constraint satisfaction problem solved using the Non-dominated Sorting Genetic Algorithm II (NSGA-II). Both …
Characterization And Measurement Of Passive And Active Metamaterial Devices, Christopher A. Lundell
Characterization And Measurement Of Passive And Active Metamaterial Devices, Christopher A. Lundell
Theses and Dissertations
This document addresses two major obstacles facing metamaterial development: uncertainty in the characterization of electromagnetic field behavior in metamaterial structures and the relatively small operational bandwidth of metamaterial structures. To address the first obstacle, a new method to characterize electromagnetic field behavior in a metamaterial is presented. This new method is a bistatic radar cross section (RCS) measurement technique. RCS measurements are well-suited to measuring bulk metamaterial samples because they show frequency dependence of scattering angles and offer common postprocessing techniques that can be useful for visualizing results. To address the second obstacle, this document characterizes the effectiveness of an …
Flexible Computing Architecture For Real Time Skin Detection, Matthew P. Hornung
Flexible Computing Architecture For Real Time Skin Detection, Matthew P. Hornung
Theses and Dissertations
In both the Air Force and Search and Rescue Communities, there is a current need to detect and characterize persons. Existing methods use red-green-blue (RGB) imagery, but produce high false alarm rates. New technology in multi-spectral skin detection is better than the existing RGB methods, but lacks a control and processing architecture to make them efficient for real time problems. We hypothesize that taking a minimalistic approach to the software design, we can perform image preprocessing, feature computation, and skin detection in real time. A number of applications require accurate detection and characterization of persons, human measurement and signature intelligence …
Spectral Domain Rf Fingerprinting For 802.11 Wireless Devices, Sheldon A. Munns
Spectral Domain Rf Fingerprinting For 802.11 Wireless Devices, Sheldon A. Munns
Theses and Dissertations
The increase in availability and reduction in cost of commercial communication devices (e.g. IEEE compliant such as 802.11, WiFi, 802.16, Bluetooth etc.) has increased wireless user exposure and the need for techniques to properly identify/classify signals for increased security measures. Communication device emissions include intentional modulation that enables correct device operation. Hardware and environmental factors alter the ideal response and induce unintentional modulation effects. If these effects (features) are sufficiently unique, it becomes possible to identify a device using its fingerprint, with potential discrimination of not only the manufacturer but possibly the serial number for a given manufacturer. Many techniques …
Modeling Computer Communication Networks In A Realistic 3d Environment, Charles R. Rowell Jr.
Modeling Computer Communication Networks In A Realistic 3d Environment, Charles R. Rowell Jr.
Theses and Dissertations
Communication network simulations have typically been visualized in the past through 2D representations, but this is insufficient for battlefield network scenarios. Visual representations of battlefield networks greatly benefit from 3D visualization due to its ability to retain asset location. This research investigates the feasibility of modeling a typical battlefield communication network in a realistic 3D manner and discusses the effects of doing so. The result is an open source, 3D network visualization tool that can create highly intuitive connected battlefield scenes, enabling the user to quickly comprehend network state. It highlights mobile assets, packet movement, and node connectivity while allowing …
Development Of A Methodology For Customizing Insider Threat Auditing On A Linux Operating System, William T. Bai
Development Of A Methodology For Customizing Insider Threat Auditing On A Linux Operating System, William T. Bai
Theses and Dissertations
Insider threats can pose a great risk to organizations and by their very nature are difficult to protect against. Auditing and system logging are capabilities present in most operating systems and can be used for detecting insider activity. However, current auditing methods are typically applied in a haphazard way, if at all, and are not conducive to contributing to an effective insider threat security policy. This research develops a methodology for designing a customized auditing and logging template for a Linux operating system. An intent-based insider threat risk assessment methodology is presented to create use case scenarios tailored to address …
Toward A Mobile Agent Relay Network, Hyon H. Kwak
Toward A Mobile Agent Relay Network, Hyon H. Kwak
Theses and Dissertations
Although wireless communication provides connectivity where hardwired links are difficult or impractical, it is still hindered by the environmental conditions where the communicators reside. Signal loss over large distances or because of intervening obstacles can be mitigated by increasing the user's transmission power or adding repeater nodes between the users. Unfortunately, increasing the signal strength strains limited power resources and increases the likelihood of eavesdropping. Stationary repeaters are impractical for highly mobile users in dangerous environments. While mobile relay nodes might be a preferred solution, a centralized control scheme saps bandwidth from important traffic and introduces a single point of …
Pulse Shape Correlation For Laser Detection And Ranging (Ladar), Brian T. Deas
Pulse Shape Correlation For Laser Detection And Ranging (Ladar), Brian T. Deas
Theses and Dissertations
Radar systems provide an important remote sensing capability, and are crucial to the layered sensing vision; a concept of operation that aims to apply the right number of the right types of sensors, in the right places, at the right times for superior battle space situational awareness. The layered sensing vision poses a range of technical challenges, including radar, that are yet to be addressed. To address the radar-specific design challenges, the research community responded with waveform diversity; a relatively new field of study which aims reduce the cost of remote sensing while improving performance. Early work suggests that the …
Application Of The Three Short Calibration Technique In A Low Frequency Focus Beam System, William E. Gunn Jr.
Application Of The Three Short Calibration Technique In A Low Frequency Focus Beam System, William E. Gunn Jr.
Theses and Dissertations
Electromagnetic material characterization is the process of determining the constitutive parameters of matter. In simple media, these parameters are permittivity and permeability. Characterization of these values is often accomplished through the use of waveguides, transmission lines, coaxial cables, and resonant cavities. Free space measurements systems are employed since they are non destructive (i.e., no sample machining is required) and broadband. Traditionally, time domain gating is utilized to mitigate systematic errors. However, an artifact of this calibration technique is band edge corruption due to data windowing. The goal of this research is to develop and apply a Three Short Calibration Technique …