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Air Force Institute of Technology

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Articles 2461 - 2490 of 5700

Full-Text Articles in Engineering

Direction Finding With Mutually Orthogonal Antennas, David F. Chick Mar 2011

Direction Finding With Mutually Orthogonal Antennas, David F. Chick

Theses and Dissertations

Estimating the direction-of-arrival of incident electromagnetic plane waves (a.k.a. direction finding or DF) has typically been accomplished in the past using arrays of spatially separated antennas. The spatial separation produces a delay in each antenna's measured voltage due to the finite propagation time as the wave strikes each antenna in succession. In this thesis, we approach the problem differently by using three antennas that have been oriented in orthogonal directions but are co-located at the origin of a coordinate system. Being co-located, this mutually orthogonal arrangement of antennas cannot detect the propagation phase delay and must rely solely on the …

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Dynamic Polymorphic Reconfiguration To Effectively “Cloak” A Circuit’S Function, Jeffrey L. Falkinburg Mar 2011

Dynamic Polymorphic Reconfiguration To Effectively “Cloak” A Circuit’S Function, Jeffrey L. Falkinburg

Theses and Dissertations

Today's society has become more dependent on the integrity and protection of digital information used in daily transactions resulting in an ever increasing need for information security. Additionally, the need for faster and more secure cryptographic algorithms to provide this information security has become paramount. Hardware implementations of cryptographic algorithms provide the necessary increase in throughput, but at a cost of leaking critical information. Side Channel Analysis (SCA) attacks allow an attacker to exploit the regular and predictable power signatures leaked by cryptographic functions used in algorithms such as RSA. In this research the focus on a means to counteract …

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Evaluation Of The Single Keybit Template Attack, Eric W. Garcia Mar 2011

Evaluation Of The Single Keybit Template Attack, Eric W. Garcia

Theses and Dissertations

Side Channel leakage is a serious threat to secure devices. Cryptographic information extraction is possible after examining any one of the various side channels, including electromagnetic. This work contributes a new method to achieve such a purpose. The Single Keybit Template Attack (SKTA) is introduced as a means to extract encryption keys from embedded processors and other integrated circuit devices performing DES encryptions by passively monitoring and exploiting unintentional RF emissions. Key extraction is accomplished by creating two templates for each bit value of the key based on instantaneous amplitude responses as a device executes DES operations. The resultant templates …

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A Multi Agent System For Flow-Based Intrusion Detection Using Reputation And Evolutionary Computation, David Hancock Mar 2011

A Multi Agent System For Flow-Based Intrusion Detection Using Reputation And Evolutionary Computation, David Hancock

Theses and Dissertations

The rising sophistication of cyber threats as well as the improvement of physical computer network properties present increasing challenges to contemporary Intrusion Detection (ID) techniques. To respond to these challenges, a multi agent system (MAS) coupled with flow-based ID techniques may effectively complement traditional ID systems. This paper develops: 1) a scalable software architecture for a new, self-organized, multi agent, flow-based ID system; and 2) a network simulation environment suitable for evaluating implementations of this MAS architecture and for other research purposes. Self-organization is achieved via 1) a reputation system that influences agent mobility in the search for effective vantage …

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Radiation Induced Fault Detection, Diagnosis, And Characterization Of Field Programmable Gate Arrays, Thomas B. Getz Mar 2011

Radiation Induced Fault Detection, Diagnosis, And Characterization Of Field Programmable Gate Arrays, Thomas B. Getz

Theses and Dissertations

The development of Field Programmable Gate Arrays (FPGAs) has been a great achievement in the world of micro-electronics. One of these devices can be programmed to do just about anything, and replace the need for thousands of individual specialized devices. Despite their great versatility, FPGAs are still extremely vulnerable to radiation from cosmic waves in space and from adversaries on the ground. Extensive research has been conducted to examine how radiation disrupts different types of FPGAs. The results show, unfortunately, that the newer FPGAs with smaller technology are even more susceptible to radiation damage than the older ones. This research …

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High Frequency Direction Finding Using Structurally Integrated Antennas On A Large Airborne Platform, Clair F. Corbin Mar 2011

High Frequency Direction Finding Using Structurally Integrated Antennas On A Large Airborne Platform, Clair F. Corbin

Theses and Dissertations

Estimating the angle of arrival (AOA) of a high frequency (HF) signal, 2-32 MHz, is challenging, especially if the antenna array is installed on a platform with dimensions on the order of one wavelength. Accurate AOA estimates are necessary for search and rescue operations and geolocating RF emitters of interest. This research examines the performance of a direction finding (DF) system using structurally integrated (SI) antennas installed on an airborne platform which allows the aircraft structure to become the receiving element. Two simulated DF systems are analyzed at 4 and 11 MHz. The relationship between the number of SI antennas …

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Malicious And Malfunctioning Node Detection Via Observed Physical Layer Data, Tyler J. Hardy Mar 2011

Malicious And Malfunctioning Node Detection Via Observed Physical Layer Data, Tyler J. Hardy

Theses and Dissertations

There are many mechanisms that can cause inadequate or unreliable information in sensor networks. A user of the network might be interested in detecting and classifying specific sensors nodes causing these problems. Several network layer based trust methods have been developed in previous research to assess these issues; in contrast this work develops a trust protocol based on observations of physical layer data collected by the sensors. Observations of physical layer data are used for decisions and calculations, and are based on just the measurements collected by the sensors. Although this information is packaged and distributed on the network layer, …

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Adaptive Quality Of Service Engine With Dynamic Queue Control, James D. Haught Mar 2011

Adaptive Quality Of Service Engine With Dynamic Queue Control, James D. Haught

Theses and Dissertations

While the current routing and congestion control algorithms in use today are often sufficient for networks with relatively static topology, these algorithms may not be sufficient for military networks where a certain level of quality of service (QoS) needs to be achieved to complete a mission. Current networking technology limits a network's ability to adapt to changes and interactions in the network, often resulting in sub-optimal performance. This research investigates the use of queue size predictions to create a network controller to optimize computer networks. These queue size predictions are made possible through the use of Kalman filters to detect …

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Holistic Network Defense: Fusing Host And Network Features For Attack Classification, Jenny W. Ji Mar 2011

Holistic Network Defense: Fusing Host And Network Features For Attack Classification, Jenny W. Ji

Theses and Dissertations

This work presents a hybrid network-host monitoring strategy, which fuses data from both the network and the host to recognize malware infections. This work focuses on three categories: Normal, Scanning, and Infected. The network-host sensor fusion is accomplished by extracting 248 features from network traffic using the Fullstats Network Feature generator and from the host using text mining, looking at the frequency of the 500 most common strings and analyzing them as word vectors. Improvements to detection performance are made by synergistically fusing network features obtained from IP packet flows and host features, obtained from text mining port, processor, logon …

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Covert Channels Within Irc, Wayne C. Henry Mar 2011

Covert Channels Within Irc, Wayne C. Henry

Theses and Dissertations

The exploration of advanced information hiding techniques is important to understand and defend against illicit data extractions over networks. Many techniques have been developed to covertly transmit data over networks, each differing in their capabilities, methods, and levels of complexity. This research introduces a new class of information hiding techniques for use over Internet Relay Chat (IRC), called the Variable Advanced Network IRC Stealth Handler (VANISH) system. Three methods for concealing information are developed under this framework to suit the needs of an attacker. These methods are referred to as the Throughput, Stealth, and Baseline scenarios. Each is designed for …

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Characteristics Of A High Intensity, Pulsed, Potassium Vapor Laser In A Heat Pipe, Edward J. Hurd Mar 2011

Characteristics Of A High Intensity, Pulsed, Potassium Vapor Laser In A Heat Pipe, Edward J. Hurd

Theses and Dissertations

This thesis research paper presents the results of experiments using an optically pumped, pulsed potassium vapor laser in a heat pipe. The absorption on the potassium D2 line, output laser characteristics, and Raman scattering in potassium vapor are discussed. The spectral full width at half maximum (FWHM) of the D2 absorption line was much greater than predicted values for pressure broadening due to the high number density of potassium atoms and the long path length. At 320°C and 0 torr of helium, the FWHM was 765 GHz. At 100 torr it was 968 GHz. At 200 torr it …

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Electromagnetic Modeling And Measurement Of Adaptive Metamaterial Structural Elements, Matthew E. Jussaume Mar 2011

Electromagnetic Modeling And Measurement Of Adaptive Metamaterial Structural Elements, Matthew E. Jussaume

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 method of prediction aided measurement is developed and exploited to examine the field interactions within metamaterial devices. The fusion of simulation and measurement techniques enhances the understanding of the physical interactions of fields in the presence of metamaterials. To address the second obstacle, this document characterizes the effectiveness of an adaptive metamaterial design that incorporates a microelectromechanical systems (MEMS) variable capacitor. Applying voltages to the …

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Memristive Properties Of Thin Film Cuprous Oxide, Brett C. Castle Mar 2011

Memristive Properties Of Thin Film Cuprous Oxide, Brett C. Castle

Theses and Dissertations

Memristive properties of thin film copper oxides with different grain sizes were characterized using tunneling atomic force microscopy (TUNA) and optical reflection measurements. The thin films containing copper ions of different chemical states were prepared by thermal oxidation of metallic copper thin films, deposited via magnetron sputtering onto silicon wafer substrates at an elevated temperature for various lengths of time. The TUNA measurements showed a memristive hysteresis in the I-V curves under an applied bias profile with an initial bias of -3.5V, a ramp up to 3.5V, and subsequent return to -3.5V. Histogram analysis of the barrier height distribution for …

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Long Term Quadrotor Stabilization, Nicolas S. Hamilton Mar 2011

Long Term Quadrotor Stabilization, Nicolas S. Hamilton

Theses and Dissertations

The work of this thesis focuses on the IMU and getting the best performance possible out of the IMU to achieve better long term stability and a better navigation solution. This is done in two ways. First, the IMU accelerometer output is examined to determine if it is possible to use accelerometers to determine attitude. If the quadrotor is stationary or moving at constant velocity, the roll and pitch angles can be determined. Additionally, the accelerometers can be used to determine angular accelerations and angular rates which are integrated to determine heading. The second approach models the quadrotor and uses …

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Airborne Pseudolites In A Global Positioning System Degraded, Halit Oktay Mar 2011

Airborne Pseudolites In A Global Positioning System Degraded, Halit Oktay

Theses and Dissertations

The high accuracy of the Global Positioning System allows for precision navigation in support of current and future military operations. However, generating a three-dimensional position using GPS requires a clear line-of-sight between the user and at least four GPS satellites, and so the GPS service can be denied in scenarios such as a street surrounded by tall buildings. Therefore, there is a need for augmentation in these environments. Pseudolites, which transmit GPS-like ranging signals, can be deployed in order to improve the geometry and provide additional ranging signals. Users can then receive and process both GPS and pseudolite signals simultaneously …

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Routing Uavs To Co-Optimize Mission Effectiveness And Network Performance With Dynamic Programming, Spenser D. Lee Mar 2011

Routing Uavs To Co-Optimize Mission Effectiveness And Network Performance With Dynamic Programming, Spenser D. Lee

Theses and Dissertations

In support of the Air Force Research Laboratory's (AFRL) vision of the layered sensing operations center, command and control intelligence surveillance and reconnaissance (C2ISR) more focus must be placed on architectures that support information systems, rather than just the information systems themselves. By extending the role of UAVs beyond simply intelligence, surveillance, and reconnaissance (ISR) operations and into a dual-role with networking operations we can better utilize our information assets. To achieve the goal of dual-role UAVs, a concrete approach to planning must be taken. This research defines a mathematical model and a non-trivial deterministic algorithmic approach to determining UAV …

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Non-Gps Navigation Using Vision-Aiding And Active Radio Range Measurements, Erich H. Lichtfuss Mar 2011

Non-Gps Navigation Using Vision-Aiding And Active Radio Range Measurements, Erich H. Lichtfuss

Theses and Dissertations

The military depends on the Global Positioning System (GPS) for a wide array of advanced weaponry guidance and precision navigation systems. Lack of GPS access makes precision navigation very difficult. Inclusion of inertial sensors in existing navigation systems provides short-term precision navigation, but drifts significantly over long-term navigation. This thesis is motivated by the need for inertial sensor drift-constraint in degraded and denied GPS environments. The navigation system developed consists of inertial sensors, a simulated barometer, three Raytheon DH500 radios, and a stereo-camera image-aiding system. The Raytheon DH500 is a combat communication radio which also provides range measurements between radios. …

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Blind Deconvolution Method Of Image Deblurring Using Convergence Of Variance, Quentin D. Macmanus Mar 2011

Blind Deconvolution Method Of Image Deblurring Using Convergence Of Variance, Quentin D. Macmanus

Theses and Dissertations

Images are used for both aerial and space imagery applications, including target detection and tracking. The current problem concerning objects in geosynchronous orbit is that they are dim and hard to resolve because of their distance. This work will further the combined effort of AFIT and AFRL to provide enhanced space situational awareness (SSA) and space surveillance. SSA is critical in a time when many countries possess the technology to put satellites into orbit. Enhanced imaging technology improves the Air Force's ability to see if foreign satellites or other space hardware are operating in the vicinity of our own assets …

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An Architecture For Improving Timeliness And Relevance Of Cyber Incident Notifications, James L. Miller Mar 2011

An Architecture For Improving Timeliness And Relevance Of Cyber Incident Notifications, James L. Miller

Theses and Dissertations

This research proposes a communications architecture to deliver timely and relevant cyber incident notifications to dependent mission stakeholders. This architecture, modeled in Unified Modeling Language (UML), eschews the traditional method of pushing notifications via message as dictated in Air Force Instruction 33-138. It instead shifts to a pull or publish and subscribe method of making notifications. Shifting this paradigm improves the notification process by empowering mission owners to identify those resources on which they depend for mission accomplishment, provides a direct conduit between providing and dependent mission owners for notifications when an incident occurs, and provides a shared representation for …

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Evaluating Information Assurance Control Effectiveness On An Air Force Supervisory Control And Data Acquisition (Scada) System, Jason R. Nielsen Mar 2011

Evaluating Information Assurance Control Effectiveness On An Air Force Supervisory Control And Data Acquisition (Scada) System, Jason R. Nielsen

Theses and Dissertations

Supervisory Control and Data Acquisition (SCADA) systems are increasingly being connected to corporate networks which has dramatically expanded their attack surface to remote cyber attack. Adversaries are targeting these systems with increasing frequency and sophistication. This thesis seeks to answer the research question addressing which Information Assurance (IA) controls are most significant for network defenders and SCADA system managers/operators to focus on in order to increase the security of critical infrastructure systems against a Stuxnet-like cyber attack. This research applies the National Institute of Science and Technology (NIST) IA controls to an attack tree modeled on a remote Stuxnet-like cyber …

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Vision Aided Inertial Navigation System Augmented With A Coded Aperture, Jamie R. Morrison Mar 2011

Vision Aided Inertial Navigation System Augmented With A Coded Aperture, Jamie R. Morrison

Theses and Dissertations

Navigation through an indoor environment is a formidable challenge for an autonomous micro air vehicle. One solution is a vision aided inertial navigation system using depth-from-defocus to determine heading and depth to features in the scene. Depth-from-defocus uses a focal blur pattern to estimate depth. As depth increases, the observable change in the focal blur is generally reduced. Consequently, as the depth of a feature to be measured increases, the measurement performance decreases. The Fresnel zone plate, used as an aperture, introduces multiple focal planes. Interference between the multiple focal planes produce changes in the aperture that extend the depth …

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Defensive Cyber Battle Damage Assessment Through Attack Methodology Modeling, Ryan T. Ostler Mar 2011

Defensive Cyber Battle Damage Assessment Through Attack Methodology Modeling, Ryan T. Ostler

Theses and Dissertations

Due to the growing sophisticated capabilities of advanced persistent cyber threats, it is necessary to understand and accurately assess cyber attack damage to digital assets. This thesis proposes a Defensive Cyber Battle Damage Assessment (DCBDA) process which utilizes the comprehensive understanding of all possible cyber attack methodologies captured in a Cyber Attack Methodology Exhaustive List (CAMEL). This research proposes CAMEL to provide detailed knowledge of cyber attack actions, methods, capabilities, forensic evidence and evidence collection methods. This product is modeled as an attack tree called the Cyber Attack Methodology Attack Tree (CAMAT). The proposed DCBDA process uses CAMAT to analyze …

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Coupling Vanishing Point Tracking With Inertial Navigation To Estimate Attitude In A Structured Environment, Dayvid Prahl Mar 2011

Coupling Vanishing Point Tracking With Inertial Navigation To Estimate Attitude In A Structured Environment, Dayvid Prahl

Theses and Dissertations

This research aims to obtain accurate and stable estimates of a vehicle's attitude by coupling consumer-grade inertial and optical sensors. This goal is pursued by first modeling both inertial and optical sensors and then developing a technique for identifying vanishing points in perspective images of a structured environment. The inertial and optical processes are then coupled to enable each one to aid the other. The vanishing point measurements are combined with the inertial data in an extended Kalman filter to produce overall attitude estimates. This technique is experimentally demonstrated in an indoor corridor setting using a motion profile designed to …

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Effects Of Cyclic Prefix Jamming Versus Noise Jamming In Ofdm Signals, Amber L. Scott Mar 2011

Effects Of Cyclic Prefix Jamming Versus Noise Jamming In Ofdm Signals, Amber L. Scott

Theses and Dissertations

Signal jamming of an orthogonal frequency-division multiplexing (OFDM) signal is simulated in MATLAB. Two different means of jamming are used to see, which is a more efficient way to disrupt a signal using the same signal power. The first way is a basic additive white Gaussian noise (AWGN) jammer that equally jams the entire signal. The second way is an AWGN jammer that targets only the cyclic prefix (CP) of the signal. These two methods of jamming are simulated using different channel models and unknowns to get varying results. The three channel models used in the simulations are the no …

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Automated Analysis Of Arm Binaries Using The Low-Level Virtual Machine Compiler Framework, Jeffrey B. Scott Mar 2011

Automated Analysis Of Arm Binaries Using The Low-Level Virtual Machine Compiler Framework, Jeffrey B. Scott

Theses and Dissertations

Binary program analysis is a critical capability for offensive and defensive operations in Cyberspace. However, many current techniques are ineffective or time-consuming and few tools can analyze code compiled for embedded processors such as those used in network interface cards, control systems and mobile phones. This research designs and implements a binary analysis system, called the Architecture-independent Binary Abstracting Code Analysis System (ABACAS), which reverses the normal program compilation process, lifting binary machine code to the Low-Level Virtual Machine (LLVM) compiler's intermediate representation, thereby enabling existing security-related analyses to be applied to binary programs. The prototype targets ARM binaries but …

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Multiple Integrated Navigation Sensors For Improving Occupancy Grid Fastslam, Christopher P. Weyers Mar 2011

Multiple Integrated Navigation Sensors For Improving Occupancy Grid Fastslam, Christopher P. Weyers

Theses and Dissertations

An autonomous vehicle must accurately observe its location within the environment to interact with objects and accomplish its mission. When its environment is unknown, the vehicle must construct a map detailing its surroundings while using it to maintain an accurate location. Such a vehicle is faced with the circularly defined Simultaneous Localization and Mapping (SLAM) problem. However difficult, SLAM is a critical component of autonomous vehicle exploration with applications to search and rescue. To current knowledge, this research presents the first SLAM solution to integrate stereo cameras, inertial measurements, and vehicle odometry into a Multiple Integrated Navigation Sensor (MINS) path. …

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Bistatic 3d Electromagnetic Scattering From A Right-Angle Dihedral At Arbitrary Orientation And Position, Andreas Z. Tempelis Mar 2011

Bistatic 3d Electromagnetic Scattering From A Right-Angle Dihedral At Arbitrary Orientation And Position, Andreas Z. Tempelis

Theses and Dissertations

A method is created to extend a bistatic 3D electromagnetic scattering solution for a dihedral at a given orientation and position to the case of arbitrary orientation and position. Results produced using this method are compared to shooting and bouncing rays (SBR) and method of moments (MoM) predictions, as well as measured data for applicable cases. The model in this thesis shows excellent agreement in magnitude and phase with SBR predictions. It also shows good agreement in magnitude with MoM predictions. Small phase differences between model and MoM data occur due to differences in the underlying scattering solution and the …

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An Analytical Model Of Nanometer Scale Viscoelastic Properties Of Polymer Surfaces Measured Using An Atomic Force Microscope, Jacob B. Goldberg Mar 2011

An Analytical Model Of Nanometer Scale Viscoelastic Properties Of Polymer Surfaces Measured Using An Atomic Force Microscope, Jacob B. Goldberg

Theses and Dissertations

The United States Air Force and the Department of Defense is increasingly interested in nanomaterials. To study these materials, one needs to measure the mechanics of materials on the nanoscale. Over the past few decades the atomic force microscope (AFM) has been used in various methods to establish local surface properties at the nanoscale. In particular, surface elasticity measurements are crucial to understanding nanoscale surface properties. Problems arise, however, when measuring soft surfaces such as polymers and biological specimens, because these materials have a more complex viscoelastic response. This research focuses on modeling an AFM dynamic nanoindentation experiment intended to …

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Optimizing Ground Times For Amc Aircraft In Afghanistan, Eric W. Bucheit Jr. Mar 2011

Optimizing Ground Times For Amc Aircraft In Afghanistan, Eric W. Bucheit Jr.

Theses and Dissertations

This research provides insight into the cargo unloading and loading process and times at three airfields in Afghanistan. Using a linear regression model and its prediction capability, a more stabilized environment is produced. This uses the times from seven historical months of continuous operations in Afghanistan and uses this information for the prediction expressions. Using this model, no throughput is lowered and early and late times are lowered by an average of seven minutes per mission. Over the course of a month, this increases planning stability by 74.1 hours. This not only impacts the planning at the downrange location, but …

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Utilizing Social Network Analysis In Support Of Nation Building, Brandon J. Bernardoni Mar 2011

Utilizing Social Network Analysis In Support Of Nation Building, Brandon J. Bernardoni

Theses and Dissertations

Social network analysis is a powerful set of techniques used by social scientists to study the formal and informal interrelations in a community. Since 9/11 these techniques have been increasingly utilized by the defense and intelligence communities to analyze terrorist networks to aid in thwarting our foes. This study investigates the use of social networks and structural holes to facilitate nation building in failed and failing states. Investigation of the underlying social structure of a community, identifying st ructural holes and gaps within the government, Security Stabilization Transition and Reconstruction Operations (SSTRO) efforts can be focused to strengthen the host …

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