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Articles 1 - 30 of 138
Full-Text Articles in Engineering
Network Security Toolkit Including Heuristic Solutions For Trust System Placement And Network Obfuscation, Gabriel H. Greve
Network Security Toolkit Including Heuristic Solutions For Trust System Placement And Network Obfuscation, Gabriel H. Greve
Theses and Dissertations
For Part I, a supervisory control and data acquisition (SCADA) network consists of a group stations and substations in a portion of the power grid. The use of Internet technology in SCADA communications as well as other factors has caused vulnerabilities. One idea to help mitigate this risk is to strategically place trust nodes to compartmentalize and secure the SCADA systems without disturbing its finely honed processes. The trust nodes combine firewall and intrusion detection technology to provide more secure communication. An optimal solution to this problem has already been developed using a mixed-integer linear programming model. Because the problem …
Flow Control Application On A Submerged Inlet Characterized By Three-Component Ldv, Tina H. Reynolds
Flow Control Application On A Submerged Inlet Characterized By Three-Component Ldv, Tina H. Reynolds
Theses and Dissertations
A submerged inlet investigation, using flow control in the form of discrete blowing, examined proximity and jet directionality to improve compressor face uniformity. The flow control locations were at the head of the ramp and part way down the ramp, providing four configurations under examination. Laser Doppler velocimetry (LDV)measurements at the throat determined the effect of the flow control based on the statistical velocity measurements. Blowing at closer proximity to the throat and targeting the largest velocity deficit region provided the best results. The airspeed and inlet velocity simulated takeoff and landing conditions; velocities ranged from Mach 0.1-0.3 at the …
Navigation With Limited Prior Information Using Time Difference Of Arrival Measurements From Signals Of Opportunity, Christopher M. Rondeau
Navigation With Limited Prior Information Using Time Difference Of Arrival Measurements From Signals Of Opportunity, Christopher M. Rondeau
Theses and Dissertations
The Global Positioning System (GPS) provides world-wide availability to high-accuracy navigation and positioning information. However, the threats to GPS are increasing, and many limitations of GPS are being encountered. Simultaneously, systems previously considered as viable backups or supplements to GPS are being shut down. This creates the need for system alternatives. Navigation using signals of opportunity (SoOP) exploits any signal that is available in a given area, regardless of whether or not the original intent of the signal was for navigation. Common techniques to compute a position estimate using SoOP include received signal strength, angle of arrival, time of arrival, …
Fatigue Behavior Of A Sic/Sic Composite At 1000⁰C In Air And In Steam, Michael W. Knauf
Fatigue Behavior Of A Sic/Sic Composite At 1000⁰C In Air And In Steam, Michael W. Knauf
Theses and Dissertations
Tension-tension fatigue behavior of a prototype Silicon Carbide/Silicon Carbide (SiC/SiC) ceramic matrix composite (CMC) material was investigated at 1000°C in laboratory air and in steam environments. The material consists of a SiC matrix reinforced with CG NICALON™ fibers woven in an eight harness satin weave (8HSW) and coated with a BN/SiC dual-layer interphase. The composite was manufactured by a Polymer Infiltration and Pyrolysis (PIP) process. A seal coat of SiC and elemental boron was applied to the test specimens after machining. The tensile stress-strain behavior was investigated and the tensile properties were measured at 1000°C. Tension-tension fatigue behavior was studied …
Performance Characterization Of A Three-Axis Hall Effect Thruster, Spencer E. Temkin
Performance Characterization Of A Three-Axis Hall Effect Thruster, Spencer E. Temkin
Theses and Dissertations
No abstract provided.
A Space Acquisition Leading Indicator Based On System Interoperation Maturity, Jason T. Shibata
A Space Acquisition Leading Indicator Based On System Interoperation Maturity, Jason T. Shibata
Theses and Dissertations
The Department of Defense‘s space acquisition enterprise has experienced numerous challenges since the advent of space power. Space borne capabilities are needed more than ever, but space acquisition frequently fails to meet its goals. The decades of space acquisition experience form a rich history that can be used to build a leading indicator of success to enable effective program execution. First, the space acquisition areas of greatest concern were determined to be cost, schedule and requirements. These areas are considered as systems composed of the people, processes and products that execute the program. Second, the vital interoperation characteristics, or attributes …
Conceptual Design And Analysis Of Service Oriented Architecture (Soa) For Command And Control Of Space Assets, Eric B. Snyder
Conceptual Design And Analysis Of Service Oriented Architecture (Soa) For Command And Control Of Space Assets, Eric B. Snyder
Theses and Dissertations
The mission-unique model that has dominated the DoD satellite Command and Control community is costly and inefficient. It requires repeatedly “reinventing” established common C2 components for each program, unnecessarily inflating budgets and delivery schedules. The effective utilization of standards is scarce, and proprietary, non-open solutions are commonplace. IT professionals have trumpeted Service Oriented Architectures (SOAs) as the solution to large enterprise situations where multiple, functionally redundant but non-compatible information systems create large recurring development, test, maintenance, and tech refresh costs. This thesis describes the current state of Service Oriented Architectures as related to satellite operations and presents a functional analysis …
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 …
Effects Of Prior Aging At 274⁰C In Argon On Inelastic Deformation Behavior Of Pmr-15 Polymer At 288⁰C: Experiment And Modeling, Joseph A. Wahlquist
Effects Of Prior Aging At 274⁰C In Argon On Inelastic Deformation Behavior Of Pmr-15 Polymer At 288⁰C: Experiment And Modeling, Joseph A. Wahlquist
Theses and Dissertations
No abstract provided.
Orbital Tori Construction Using Trajectory Following Spectral Methods, Ralph E. Bordner Iii
Orbital Tori Construction Using Trajectory Following Spectral Methods, Ralph E. Bordner Iii
Theses and Dissertations
By assuming the motion of a satellite about the earth’s geopotential mimics the known Kolmogorov-Arnold-Moser (KAM) solution of a lightly perturbed integrable Hamiltonian system, this research focused on applying trajectory following spectral methods to estimate orbital tori from sampled orbital data. From an estimated basis frequency set, orbital data was decomposed into multi-periodic Fourier series, essentially compressing ephemerides for long-term use. Real-world Global Positioning System (GPS) orbital tracks were decomposed and reconstructed with error from as low as few kilometers per coordinate axis over a 10-week span to tens of kilometers per coordinate axis over the same time period, depending …
Knowledge-Based Decision Support In Department Of Defense Acquisitions, Clifton L. Hicks
Knowledge-Based Decision Support In Department Of Defense Acquisitions, Clifton L. Hicks
Theses and Dissertations
Despite numerous reform efforts over the past 30 years, acquisition programs in the Department of Defense (DoD) continue to experience cost overruns and schedule delays. One contributing factor is the decision-making process used by defense officials. The General Accounting Office (GAO) has stated that ‘poor program outcomes are the lack of widespread adoption of a knowledge-based acquisition process within DoD despite polices that support such a process. A knowledge-based business case at the outset of each program would alleviate overpromising on cost, schedule, and performance and would empower program managers.’ Effective decision-making for acquisition programs is very important. It not …
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 …
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 …
Exploring The Effects Of International Traffic In Arms Regulations Restrictions On Innovation In The U.S. Space Industrial Base, Kalliroi L. Landry
Exploring The Effects Of International Traffic In Arms Regulations Restrictions On Innovation In The U.S. Space Industrial Base, Kalliroi L. Landry
Theses and Dissertations
The International Traffic in Arms Regulations (ITAR) are used to protect United States (U.S.) military technologies. However, changes to ITAR export controls regarding space technologies have had a major impact to the U.S. space industry. The literature mentions a concern for the health of lower-tier firms because they are a major source of innovation, but there is no additional information considering the effects of ITAR on space innovation at those lower tiers. The purpose of this thesis was to explore the implications of continuing the current ITAR restrictions with regard to innovation in the space industry. This research used a …
Hijacking User Uploads To Online Persistent Data Repositories For Covert Data Exfiltration, Curtis P. Barnard
Hijacking User Uploads To Online Persistent Data Repositories For Covert Data Exfiltration, Curtis P. Barnard
Theses and Dissertations
As malware has evolved over the years, it has gone from harmless programs that copy themselves into other executables to modern day botnets that perform bank fraud and identity theft. Modern malware often has a need to communicate back to the author, or other machines that are also infected. Several techniques for transmitting this data covertly have been developed over the years which vary significantly in their level of sophistication. This research creates a new covert channel technique for stealing information from a network by piggybacking on user-generated network traffic. Specifically, steganography drop boxes and passive covert channels are merged …
Reputation-Based Internet Protocol Security: A Multilayer Security Framework For Mobil Ad Hoc Networks, Timothy H. Lacey
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 …
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 …
Providing A Theoretical Basis For Nanotoxicity Risk Analysis Departing From Traditional Physiologically-Based Pharmacokinetic (Pbpk) Modeling, Dirk P. Yamamoto
Providing A Theoretical Basis For Nanotoxicity Risk Analysis Departing From Traditional Physiologically-Based Pharmacokinetic (Pbpk) Modeling, Dirk P. Yamamoto
Theses and Dissertations
The same novel properties of engineered nanoparticles that make them attractive may also present unique exposure risks. But, the traditional physiologically-based pharmacokinetic (PBPK) modeling assumption of instantaneous equilibration likely does not apply to nanoparticles. This simulation-based research begins with development of a model that includes diffusion, active transport, and carrier mediated transport. An eigenvalue analysis methodology was developed to examine model behavior to focus future research. Simulations using the physicochemical properties of size, shape, surface coating, and surface charge were performed and an equation was determined which estimates area under the curve for arterial blood concentration, which is a surrogate …
Satellite Capabilities Mapping - Utilizing Small Satellites, David A. Grigsby
Satellite Capabilities Mapping - Utilizing Small Satellites, David A. Grigsby
Theses and Dissertations
The cost and schedule advantages small satellites have over larger legacy systems have been studied, but there has been very little experimentation performed to determine whether small satellites can actually deliver the capabilities of larger spacecraft. To date, a desired operational capability has not been fully realized by a scalable satellite design. Advances in sensor technology have led to significant reductions in size, weight, and power (SWaP) presenting an opportunity to exploit the evolution of space operations by using small satellites to perform specific missions. This paper describes a methodology that maps a specific set of large space vehicle capabilities …
Improving The Quality Of Service And Security Of Military Networks With A Network Tasking Order Process, Matthew D. Compton
Improving The Quality Of Service And Security Of Military Networks With A Network Tasking Order Process, Matthew D. Compton
Theses and Dissertations
This research presents a Network Tasking Order process that collects mission plans, network capabilities, and historical records to build a Network Tasking Order (NTO). The NTO document directs the form and usage of the network, much like an Air Tasking Order (ATO) directs the usage of air power. The NTO process is fleshed out with the content and format of the NTO given herein for the first time. Tools such as topology control algorithms are then shown through simulation to improve the quality of service of the network by finding favorable ways to connect the assets identified during the NTO …
All Solid-State Mid-Ir Laser Development, Nonlinear Absorption Investigation And Laser-Induced Damage Study, Torrey J. Wagner
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 …
Mission Assurance: A Review Of Continuity Of Operations Guidance For Application To Cyber Incident Mission Impact Assessment (Cimia), Brian L. Hale
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 …
Deterministic, Efficient Variation Of Circuit Components To Improve Resistance To Reverse Engineering, Daniel F. Koranek
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. …
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 …
A Dynamically Configurable Log-Based Distributed Security Event Detection Methodology Using Simple Event Correlator, Justin M. Myers
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 …
An Integrity Framework For Image-Based Navigation Systems, Craig D. Larson
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 …
Developing A Hybrid Virtualization Platform Design For Cyber Warfare And Simulation, Kyle E. Stewart
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 …
A Photogrammetry-Based Hybrid System For Dynamic Tracking And Measurement, Daniel P. Magree
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 …
Velocity Plume Profiles For Hall Thrusters Using Laser Diagnostic, Daniel B. Lee
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 …