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Articles 2581 - 2610 of 5700

Full-Text Articles in Engineering

Reputation-Based Internet Protocol Security: A Multilayer Security Framework For Mobil Ad Hoc Networks, Timothy H. Lacey Sep 2010

Reputation-Based Internet Protocol Security: A Multilayer Security Framework For Mobil Ad Hoc Networks, Timothy H. Lacey

Theses and Dissertations

This research effort examines the theory, application, and results for a Reputation-based Internet Protocol Security (RIPSec) framework that provides security for an ad-hoc network operating in a hostile environment. In RIPSec, protection from external threats is provided in the form of encrypted communication links and encryption-wrapped nodes while internal threats are mitigated by behavior grading that assigns reputations to nodes based on their demonstrated participation in the routing process. Network availability is provided by behavior grading and round-robin multipath routing. If a node behaves faithfully, it earns a positive reputation over time. If a node misbehaves (for any number of …


Applying Image Matching To Video Analysis, Adam J. Behring Sep 2010

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 …


All Solid-State Mid-Ir Laser Development, Nonlinear Absorption Investigation And Laser-Induced Damage Study, Torrey J. Wagner Sep 2010

All Solid-State Mid-Ir Laser Development, Nonlinear Absorption Investigation And Laser-Induced Damage Study, Torrey J. Wagner

Theses and Dissertations

In this research, nonlinear optical absorption coefficients and laser-induced damage thresholds are measured in Ge and GaSb, which are materials that are used in IR detectors. Using a simultaneous fitting technique to extract nonlinear absorption coefficients from data at two pulse widths, two-photon and free-carrier absorption coefficients are measured in Ge and GaSb at 2.05 and 2.5 μm for the first time. At these wavelengths, nonlinear absorption is the primary damage mechanism, and damage thresholds at picosecond and nanosecond pulse widths were measured and agreed well with modeled thresholds using experimentally measured parameters. The damage threshold for a single-layer Al …


The Electronic Structure And Secondary Pyroelectric Properties Of Lithium Tetraborate, Volodymyr T. Adamiv, Yaroslav V. Burak, David J. Wooten, John W. Mcclory, James C. Petrosky, Ihor Ketsman, Ya B. Losovyj, Peter A. Dowben, Jie Xiao Sep 2010

The Electronic Structure And Secondary Pyroelectric Properties Of Lithium Tetraborate, Volodymyr T. Adamiv, Yaroslav V. Burak, David J. Wooten, John W. Mcclory, James C. Petrosky, Ihor Ketsman, Ya B. Losovyj, Peter A. Dowben, Jie Xiao

Faculty Publications

We review the pyroelectric properties and electronic structure of Li2B4O7(110) and Li2B4O7(100) surfaces. There is evidence for a pyroelectric current along the [110] direction of stoichiometric Li2B4O7 so that the pyroelectric coefficient is nonzero but roughly 103 smaller than along the [001] direction of spontaneous polarization. Abrupt decreases in the pyroelectric coefficient along the [110] direction can be correlated with anomalies in the elastic stiffness contributing to the concept that the pyroelectric coefficient is not simply a vector but has qualities of …


International Space Station Systems Engineering Case Study, Air Force Center For Systems Engineering, Bill Stockman, Joe Boyle, John Bacon Aug 2010

International Space Station Systems Engineering Case Study, Air Force Center For Systems Engineering, Bill Stockman, Joe Boyle, John Bacon

AFIT Documents

This case study on the International Space Station considers what many believe to have been the ultimate international engineering project in history. The initial plans involved the direct participation of 16 nations, 88 launches and over 160 spacewalks-more space activities than NASA had accomplished prior to the 1993 International Space Station decision. Probably more important was the significant leap in System Engineering (SE) execution that would be required to build and operate a multi-national space station. In a short period of time, NASA and its partners had to work out how to integrate culturally different SE approaches, designs, languages and …


Analytical Solutions For Efficient Interpretation Of Single-Well Push-Pull Tracer Tests, Junqi Huang, John A. Christ, Mark N. Goltz Aug 2010

Analytical Solutions For Efficient Interpretation Of Single-Well Push-Pull Tracer Tests, Junqi Huang, John A. Christ, Mark N. Goltz

Faculty Publications

Single-well push-pull tracer tests have been used to characterize the extent, fate, and transport of subsurface contamination. Analytical solutions provide one alternative for interpreting test results. In this work, an exact analytical solution to two-dimensional equations describing the governing processes acting on a dissolved compound during a modified push-pull test (advection, longitudinal and transverse dispersion, first-order decay, and rate-limited sorption/partitioning in steady, divergent, and convergent flow fields) is developed. The coupling of this solution with inverse modeling to estimate aquifer parameters provides an efficient methodology for subsurface characterization. Synthetic data for single-well push-pull tests are employed to demonstrate the utility …


An Integrity Framework For Image-Based Navigation Systems, Craig D. Larson Jun 2010

An Integrity Framework For Image-Based Navigation Systems, Craig D. Larson

Theses and Dissertations

This work first examines fundamental differences between measurement models established for GPS and those of proposed image-based navigation systems. In contrast to single value per satellite GPS pseudorange measurements, image measurements are inherently angle-based and represent pixel coordinate pairs for each mapped target. Thus, in the image-based case, special consideration must be given to the units of the transformations between the states and measurements, and also to the fact that multiple rows of the observation matrix relate to particular error states. An algorithm is developed to instantiate a framework for image-based integrity analogous to that of GPS RAIM. The algorithm …


Attaining Realistic Simulations Of Mobile Ad-Hoc Networks, Derek J. Huber Jun 2010

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 …


Deterministic, Efficient Variation Of Circuit Components To Improve Resistance To Reverse Engineering, Daniel F. Koranek Jun 2010

Deterministic, Efficient Variation Of Circuit Components To Improve Resistance To Reverse Engineering, Daniel F. Koranek

Theses and Dissertations

This research proposes two alternative methods for generating semantically equivalent circuit variants which leave the circuit's internal structure pseudo-randomly determined. Component fusion deterministically selects subcircuits using a component identification algorithm and replaces them using a deterministic algorithm that generates canonical logic forms. Component encryption seeks to alter the semantics of individual circuit components using an encoding function, but preserves the overall circuit semantics by decoding signal values later in the circuit. Experiments were conducted to examine the performance of component fusion and component encryption against representative trials of subcircuit selection-and-replacement and Boundary Blurring, two previously defined methods for circuit obfuscation. …


A Photogrammetry-Based Hybrid System For Dynamic Tracking And Measurement, Daniel P. Magree Jun 2010

A Photogrammetry-Based Hybrid System For Dynamic Tracking And Measurement, Daniel P. Magree

Theses and Dissertations

Noncontact measurements of lightweight flexible aerospace structures present several challenges. Objects are usually mounted on a test stand because current noncontact measurement techniques require that the net motion of the object be zero. However, it is often desirable to take measurements of the object under operational conditions, and in the case of miniature aerial vehicles (MAVs) and deploying space structures, the test article will undergo significant translational motion. This thesis describes a hybrid noncontact measurement system which will enable measurement of structural kinematics of an object freely moving about a volume. By using a real-time videogrammetry system, a set of …


A Dynamically Configurable Log-Based Distributed Security Event Detection Methodology Using Simple Event Correlator, Justin M. Myers Jun 2010

A Dynamically Configurable Log-Based Distributed Security Event Detection Methodology Using Simple Event Correlator, Justin M. Myers

Theses and Dissertations

Log event correlation is an effective means of detecting system faults and security breaches encountered in information technology environments. Centralized, database-driven log event correlation is common, but suffers from flaws such as high network bandwidth utilization, significant requirements for system resources, and difficulty in detecting certain suspicious behaviors. This research presents a distributed event correlation system which performs security event detection, and compares it with a centralized alternative. The comparison measures the value in distributed event correlation by considering network bandwidth utilization, detection capability and database query efficiency, as well as through the implementation of remote configuration scripts and correlation …


Mission Assurance: A Review Of Continuity Of Operations Guidance For Application To Cyber Incident Mission Impact Assessment (Cimia), Brian L. Hale Jun 2010

Mission Assurance: A Review Of Continuity Of Operations Guidance For Application To Cyber Incident Mission Impact Assessment (Cimia), Brian L. Hale

Theses and Dissertations

Military organizations have embedded information technology (IT) into their core mission processes as a means to increase operational efficiency, improve decision-making quality, and shorten the sensor-to-shooter cycle. This IT-to-mission dependence can place the organizational mission at risk when an information incident (e.g., the loss or manipulation of a critical information resource) occurs. Non-military organizations typically address this type of IT risk through an introspective, enterprise-wide focused risk management program that continuously identifies, prioritizes, and documents risks so an economical set of control measures (e.g., people, processes, technology) can be selected to mitigate the risks to an acceptable level. The explicit …


Architectural Considerations For Single Operator Management Of Multiple Unmanned Aerial Vehicles, Gabriel T. Bugajski Jun 2010

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.


Simulation Modeling And Analysis Of Tnmcs For The B-1 Strategic Bomber, Carl R. Parson Jun 2010

Simulation Modeling And Analysis Of Tnmcs For The B-1 Strategic Bomber, Carl R. Parson

Theses and Dissertations

Simulation provides a method of modeling complex systems which would otherwise be impractical for quantitative experimentation. While other analytic techniques have been used to explore Total Non-Mission Capable [due to] Supply (TNMCS) rates, simulation offers a novel approach to discovering what aspects of the supply chain impact this metric. This research develops a discrete event simulation to investigate factors which affect TNMCS rates for the B-1B by modeling the core processes within the Air Force (AF) supply chain. A notional fleet of 16 aircraft at a single air base (Ellsworth AFB, SD) is modeled based on historical supply and maintenance …


Use Of Negation In Search, Kristen M. Lancaster Jun 2010

Use Of Negation In Search, Kristen M. Lancaster

Theses and Dissertations

Boolean algebra was developed in the 1840s. Since that time, negation, one of the three basic concepts in Boolean algebra, has influenced the fields of information science and information retrieval, particularly in the modern computer era. In Web search engines, one of the present manifestations of information retrieval, little use is being made of this functionality and so little attention is given to it in the literature. This study aims to bolster the understanding of the use and usefulness of negation. Specifically, an Internet search task was developed for which negation was the most appropriate search strategy. This search task …


Developing A Hybrid Virtualization Platform Design For Cyber Warfare And Simulation, Kyle E. Stewart Jun 2010

Developing A Hybrid Virtualization Platform Design For Cyber Warfare And Simulation, Kyle E. Stewart

Theses and Dissertations

Virtualization is a technique used to model and simulate the cyber domain, as well as train and educate. Different types of virtualization techniques exist that each support a unique set of benefits and requirements. This research proposes a novel design that incorporates host and network virtualization concepts for a cyber warfare training platform. At the host level, hybrid virtualization combines full and operating system virtualization techniques in order to leverage the benefits and minimize the drawbacks of each individual technique. Network virtualization allows virtual machines to connect in flexible topologies, but it also incurs additional processing overhead. Quantitative analysis falls …


Performance Evaluation Of A Field Programmable Gate Array-Based System For Detecting And Tracking Peer-To-Peer Protocols On A Gigabit Ethernet Network, Brennon D. Thomas Jun 2010

Performance Evaluation Of A Field Programmable Gate Array-Based System For Detecting And Tracking Peer-To-Peer Protocols On A Gigabit Ethernet Network, Brennon D. Thomas

Theses and Dissertations

Recent years have seen a massive increase in illegal, suspicious, and malicious traffic traversing government and military computer networks. Some examples include illegal file distribution and disclosure of sensitive information using the BitTorrent file sharing protocol, criminals and terrorists using Voice over Internet Protocol (VoIP) technologies to communicate, and foreign entities exfiltrating sensitive data from government, military, and Department of Defense contractor networks. As a result of these growing threats, the TRacking and Analysis for Peer-to-Peer (TRAPP) system was developed in 2008 to detect BitTorrent and VoIP traffic of interest. The TRAPP system, designed on a Xilinx Virtex-II Pro Field …


Velocity Plume Profiles For Hall Thrusters Using Laser Diagnostic, Daniel B. Lee Jun 2010

Velocity Plume Profiles For Hall Thrusters Using Laser Diagnostic, Daniel B. Lee

Theses and Dissertations

This research built a non-intrusive laser diagnostic tool using Laser Induced Fluorescence (LIF) and absorption techniques to measure the velocity and density plume profiles of low powered Hall thrusters. This tool was then applied to a Busek 200W Hall thruster to validate the performance against previous research on the same thruster. A laser frequency sweep through 834.72 nm produced LIF signals for ionized xenon –collected at 541.9 nm – in the thruster plume and absorption data outside the plume at a neutral transition at 834.68 nm. The absorption data provided a baseline reference to calculate the axial and radially velocity …


Stochastic Feature Selection With Distributed Feature Spacing For Hyperspectral Data, Jeffrey D. Clark, Michael J. Mendenhall, Gilbert L. Peterson Jun 2010

Stochastic Feature Selection With Distributed Feature Spacing For Hyperspectral Data, Jeffrey D. Clark, Michael J. Mendenhall, Gilbert L. Peterson

Faculty Publications

Feature subset selection is a well studied problem in machine learning. One short-coming of many methods is the selection of highly correlated features; a characteristic of hyperspectral data. A novel stochastic feature selection method with three major components is presented. First, we present an optimized feature selection method that maximizes a heuristic using a simulated annealing search which increases the chance of avoiding locally optimum solutions. Second, we exploit local cross correlation pair-wise amongst classes of interest to select suitable features for class discrimination. Third, we adopt the concept of distributed spacing from the multi-objective optimization community to distribute features …


A Locally Adaptable Iterative Rx Detector, Yuri P. Taitano, Brian G. Geier, Kenneth W. Bauer May 2010

A Locally Adaptable Iterative Rx Detector, Yuri P. Taitano, Brian G. Geier, Kenneth W. Bauer

Faculty Publications

We present an unsupervised anomaly detection method for hyperspectral imagery (HSI) based on data characteristics inherit in HSI. A locally adaptive technique of iteratively refining the well-known RX detector (LAIRX) is developed. The technique is motivated by the need for better first- and second-order statistic estimation via avoidance of anomaly presence. Overall, experiments show favorable Receiver Operating Characteristic (ROC) curves when compared to a global anomaly detector based upon the Support Vector Data Description (SVDD) algorithm, the conventional RX detector, and decomposed versions of the LAIRX detector. Furthermore, the utilization of parallel and distributed processing allows fast processing time making …


Cyber This, Cyber That...So What?, Eric D. Trias, Bryan Bell Apr 2010

Cyber This, Cyber That...So What?, Eric D. Trias, Bryan Bell

Faculty Publications

This article endorses the idea that cyber operations may be conducted in all war-fighting domains: air, space, cyberspace, land, and sea. In addition, despite the immaturity of cyberspace operational doctrines, the doctrines from air and space remain relevant and applicable to the cyberspace domain. Cyber operations are just another set of tools in the commander's toolbox. Although cyber operations have distinct ways of achieving effects, from an Air Force perspective they are similar too the air and space operations that support air and space (and cyberspace) functions. Known and established cyber operations provide war fighters with viable options to kinetic …


Real Time Fault Detection And Diagnostics Using Fpga-Based Architecture, Nathan P. Naber Mar 2010

Real Time Fault Detection And Diagnostics Using Fpga-Based Architecture, Nathan P. Naber

Theses and Dissertations

Errors within circuits caused by radiation continue to be an important concern to developers. A new methodology of real time fault detection and diagnostics utilizing FPGA based architectures while under radiation were investigated in this research. The contributions of this research are focused on three areas; a full test platform to evaluate a circuit while under irradiation, an algorithm to detect and diagnose fault locations within a circuit, and finally to characterize Triple Design Triple Modular Redundancy (TDTMR), a new form of TMR. Five different test setups, injected fault test, gamma radiation test, thermal radiation test, optical laser test, and …


Reputation-Based Trust For A Cooperative, Agent-Based Backup Protection Scheme For Power Networks, John F. Borowski Mar 2010

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 …


Handshaking Protocols And Jamming Mechanisms For Blind Rendezvous In A Dynamic Spectrum Access Environment, Aaron A. Gross Mar 2010

Handshaking Protocols And Jamming Mechanisms For Blind Rendezvous In A Dynamic Spectrum Access Environment, Aaron A. Gross

Theses and Dissertations

Blind frequency rendezvous is an important process for bootstrapping communications between radios without the use of pre-existing infrastructure or common control channel in a Dynamic Spectrum Access (DSA) environment. In this process, radios attempt to arrive in the same frequency channel and recognize each other’s presence in changing, under-utilized spectrum. This paper refines existing blind rendezvous techniques by introducing a handshaking algorithm for setting up communications once two radios have arrived in the same frequency channel. It then investigates the effect of different jamming techniques on blind rendezvous algorithms that utilize this handshake. The handshake performance is measured by determining …


Codifying Information Assurance Controls For Department Of Defense (Dod) Supervisory Control And Data Acquisition (Scada) Systems (U), Eddie A. Mendezllovet Mar 2010

Codifying Information Assurance Controls For Department Of Defense (Dod) Supervisory Control And Data Acquisition (Scada) Systems (U), Eddie A. Mendezllovet

Theses and Dissertations

Protecting DoD critical infrastructure resources and Supervisory Control and Data Acquisition (SCADA) systems from cyber attacks is becoming an increasingly challenging task. DoD Information Assurance controls provide a sound framework to achieve an appropriate level of confidentiality, integrity, and availability. However, these controls have not been updated since 2003 and currently do not adequately address the security of DoD SCADA systems. This research sampled U.S. Air Force Civil Engineering subject matter experts representing eight Major Commands that manage and operate SCADA systems. They ranked 30 IA controls in three categories, and evaluated eight SCADA specific IA controls for inclusion into …


Scalable And Fault Tolerant Group Key Management, Nicholas A. Lupien Mar 2010

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 …


Developing An Effective And Efficient Real Time Strategy Agent For Use As A Computer Generated Force, Kurt Weissgerber Mar 2010

Developing An Effective And Efficient Real Time Strategy Agent For Use As A Computer Generated Force, Kurt Weissgerber

Theses and Dissertations

Computer Generated Forces (CGF) are used to represent units or individuals in military training and constructive simulation. The use of CGF significantly reduces the time and money required for effective training. For CGF to be effective, they must behave as a human would in the same environment. Real Time Strategy (RTS) games place players in control of a large force whose goal is to defeat the opponent. The military setting of RTS games makes them an excellent platform for the development and testing of CGF. While there has been significant research in RTS agent development, most of the developed agents …


Effects Of Channel Mismatches On Beamforming And Signal Detection, Christopher I. Allen Mar 2010

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 …


Static And Dynamic Component Obfuscation On Reconfigurable Devices, Camdon R. Cady Mar 2010

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 …


Improved Multispectral Skin Detection And Its Application To Search Space Reduction For Dismount Detection Based On Histograms Of Oriented Gradients, Adam L. Brooks Mar 2010

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 …