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Articles 1171 - 1200 of 2084
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Aerial Recovery Of Micro Air Vehicles: Orbit Estimation And Tracking, Daniel Clarke Carlson
Aerial Recovery Of Micro Air Vehicles: Orbit Estimation And Tracking, Daniel Clarke Carlson
Theses and Dissertations
Aerial recovery of autonomous micro air vehicles (MAVs) presents many unique challenges due to the difference in size and speed of the recovery vehicle and MAV. This thesis presents algorithms to enable an autonomous MAV to estimate the orbit of a recovery vehicle and track the orbit until the final docking phase. Methods for estimating ellipses that are rotated out of the x − y plane are developed and demonstrated through simulation. These algorithms are shown to be robust to noise and stable numerically. Parameter update methods that are computationally inexpensive, such as recursive least squares and Kalman filtering, are …
Handshaking Protocols And Jamming Mechanisms For Blind Rendezvous In A Dynamic Spectrum Access Environment, Aaron A. Gross
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 …
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 …
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 …
An Approach To Large Scale Radar-Based Modeling And Simulation, Lester C. Long Iv
An Approach To Large Scale Radar-Based Modeling And Simulation, Lester C. Long Iv
Theses and Dissertations
This research presents a method of aggregating, or reducing the resolution, of a commonly available Department of Defense (DoD) simulation. It addresses the differences between varying levels of resolution and scope used in the DoD’s hierarchy of models pyramid. A data representation that aggregates engagement-level simulation data to use at a lower resolution level, the mission-level, is presented and analyzed. Two formats of implementing this data representation are developed and compared: the rigid cylinder format and the expanding tables format. The rigid cylinder format provides an intuitive way to visualize the data and is used to develop the theory. The …
Increasing The Sensitivity Of Surface Acoustic Wave (Saw) Chemical Sensors And Other Chemical Sensing Investigations, Nina R. Smith
Increasing The Sensitivity Of Surface Acoustic Wave (Saw) Chemical Sensors And Other Chemical Sensing Investigations, Nina R. Smith
Theses and Dissertations
The work involves the fabrication and testing of three different surface acoustic wave (SAW) device designs, an investigation of nanowires sensitive to chemicals and preconcentrator prototypes to include with chemical sensors. The SAW chemical sensor designs include modifications to a basic SAW device to see if the sensitivity of the SAW device is increased. The modifications consist of etched trenches along the propagation field, coating the device with carbon nanotubes (CNTs) under the chemically sensitive layer and coating CNTs on top of the chemically sensitive layer. SAW devices are coated with Nafion®, a polymer sensitive to ethanol. The tests indicate …
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 …
Analysis Of Hybrid-Electric Propulsion System Designs For Small Unmanned Aircraft Systems, Ryan M. Hiserote
Analysis Of Hybrid-Electric Propulsion System Designs For Small Unmanned Aircraft Systems, Ryan M. Hiserote
Theses and Dissertations
Currently fielded electric-powered small unmanned aircraft systems (UAS) lack the endurance desired by warfighters, while their internal combustion engine (ICE) driven counterparts generate mission compromising acoustic and thermal signatures. Parallel hybrid-electric propulsion systems would meet the military’s needs by combining the advantages of hydrocarbon and electric power systems. Three distinct parallel hybrid-electric system designs, each with three unique battery discharging profiles, were analyzed and compared using a constrained static optimization formulation based upon traditional aircraft design equations. Each system combined an ICE sized for cruise speed with an electric motor sized for endurance speed. The nine hybrid variations were compared …
Structural Response Of Slotted Waveguide Antenna Stiffened Structure Components Under Compression, Joseph W. Sabat Jr.
Structural Response Of Slotted Waveguide Antenna Stiffened Structure Components Under Compression, Joseph W. Sabat Jr.
Theses and Dissertations
The Slotted Waveguide Antenna Stiffened Structure (SWASS) is an aircraft system that can provide the capabilities of a stiffened panel skin structure and a slotted waveguide radar antenna simultaneously. The system made from carbon fiber reinforced polymers is designed around a 10 GHz radar frequency in the X-band range and uses a WR-90 waveguide as a baseline for design. The system is designed for integration into fuselage or wing sections of intelligence, surveillance, and reconnaissance (ISR) aircraft and would increase the system performance through the availability of increased area and decreased system weight. Elemental parts of the SWASS structure were …
Simulation And Application Of Gpops For Trajectory Optimization And Mission Planning Tool, Danielle E. Yaple
Simulation And Application Of Gpops For Trajectory Optimization And Mission Planning Tool, Danielle E. Yaple
Theses and Dissertations
Rapid trajectory generation is crucial to prompt global warfare. To meet the USAF’s objective of Persistent and Responsive Precision Engagement, a rapid mission planning tool is required. This research creates the framework for the mission planning tool and provides a sample optimal trajectory which is solved using the GPOPS software package. GPOPS employs a Gaussian pseudospectral method to solve the non-linear equations of motion with both end conditions and path constraints. By simultaneously solving the entire trajectory based on an initial guess and small number of nodes, this method is ideal for generating rapid solutions. The sample case is a …
A Simulation Based Methodology To Examine The B-1b'S An/Alq-161 Maintenance Process, Ricardo R. Garza
A Simulation Based Methodology To Examine The B-1b'S An/Alq-161 Maintenance Process, Ricardo R. Garza
Theses and Dissertations
The B-1 Bomber is the Air Force’s only supersonic, conventional-only strike platform. This thesis looks at the maintenance procedures associated with the defensive electronic counter measure (ECM) system on the B-1B, designated the AN/ALQ-161. Computer simulation of the current line-replaceable-unit maintenance network for Ellsworth AFB and Dyess AFB is modeled. In addition, two hypothetical repair networks are proposed and analyzed. This research considers the applicability of this type of computer simulation, using ARENA software to study the AN/ALQ-161 repair system. The contribution of this research is a discrete simulation methodology specific to the AN/ALQ-161 LRU repair line. Two response variables …
Stealthy River Navigation In Jungle Combat Conditions, Fabio Ayres Cardoso
Stealthy River Navigation In Jungle Combat Conditions, Fabio Ayres Cardoso
Theses and Dissertations
One of the biggest challenges for Brazilian military logisticians is to support effective jungle warfare for both real and training operations carried out by their combat forces in the Amazonian region. The jungle's heat, humidity, and dense vegetation put significant demands on the supply chain. Further, because of the difficulties of land or air transportation, water transport is the most reasonable transportation option to sustain these deployed forces. Planners must select from among the available watercourses those whose surroundings provide stealthy navigation to the combat force location where the requested supplies can be safely unloaded. We seek a method of …
Screening And Sufficiency In Multiobjective Decision Problems With Large Alternative Sets, Michael D. Cote
Screening And Sufficiency In Multiobjective Decision Problems With Large Alternative Sets, Michael D. Cote
Theses and Dissertations
Portfolio selection problems with combinatorially-large alternative sets can be impossible to evaluate precisely on a reasonable timescale. When portfolios require complex modeling for performance assessment, prohibitive computational processing times can result. Eliminating a small number of alternatives through an intelligent screening process can greatly reduce the number of alternative combinations, thereby decreasing a problem's evaluation time and cost. A methodology was developed for the class of hierarchical portfolio selection problems in which multiple objectives are all judged on the same sub-objectives. First, a novel capability-based alternative screening process was devised to identify and remove poor alternatives, thereby reducing the number …
High Volume Air Sampling For Viral Aerosols: A Comparative Approach, Casey W. Cooper
High Volume Air Sampling For Viral Aerosols: A Comparative Approach, Casey W. Cooper
Theses and Dissertations
The United States Air Force has high volume biological air sampling equipment available including the XMX/2L-MIL and DFU-1000. Neither system has been evaluated for effectiveness in the collection of viruses. Furthermore, decontamination methods have not been evaluated for these systems after use in sampling for a viral agent. MS2 bacteriophage was used as a surrogate virus. Aerosolized MS2 was released into a 12 m3 exposure chamber. High and moderate airborne concentrations of MS2 were evaluated. Low volume impingers were used for comparative purposes as well. Samples were analyzed using plaque assay and polymerase chain reaction (PCR). At high viral loads …
Method Of Measuring The Economic Impact Of A Radiological Dispersal Event Within An Urban Environment, Antoine N. Munfakh
Method Of Measuring The Economic Impact Of A Radiological Dispersal Event Within An Urban Environment, Antoine N. Munfakh
Theses and Dissertations
A radiological dispersal event (RDE) is the result of a Radiological Dispersal Device (RDD) or a dirty bomb. An RDD is a low‐yield conventional bomb surrounded by radiological material (RM) such as Cesium‐137 or Cobalt‐60. Upon detonation, the blast of the conventional explosive is designed to spread the RM over a wide area. The RM will then be inhaled or ingested by people, or otherwise absorbed into the environment. An RDD is an affordable, feasible, and economically devastating option for terrorist groups. Possible RM could be stolen or acquired cheaply from the millions of radioactive sources used worldwide in industry, …
Low Dose Sarin Leads To Murine Cardiac Dysfunction, Michael W. Horenziak
Low Dose Sarin Leads To Murine Cardiac Dysfunction, Michael W. Horenziak
Theses and Dissertations
It has been reported that low dose sarin is associated with long-term pathology in the brain and heart; however, the effects of sarin on the heart have yet to be determined. In addition, sarin has been implicated as an etiological agent in Gulf War Illness. Thus, the role of sarin in producing illness has important military consequences. This study used echocardiography, electrocardiography, and histology to determine sarin’s effect on the murine cardiovascular system. C57BL/6J mice were injected with sarin at 0.4 LD50, 0.5 LD50, or saline on two consecutive days and studied for 10 weeks post exposure. The sarin animals …
Development Of Morphing Aircraft Structure Using Smp, Soo-Chan Jee
Development Of Morphing Aircraft Structure Using Smp, Soo-Chan Jee
Theses and Dissertations
The U.S Air Force needs new aircraft which provide longer flight time, less fuel consumption, better aerodynamics in order to perform Air Force missions successfully as the mission environment changes rapidly. A morphing wing aircraft is considered as a potential new aircraft for those missions. This thesis explores Shape Memory Polymer (SMP) properties test results and its application for morphing wing skin. Several SMP composite laminates were considered for investigating shape changing characteristics required for morphing skin. The braided composite preforms used in making SMP composites were explored in morphing wing operating system based on the results of property tests. …
The Uav Continuous Coverage Problem, Taegyun Ha
The Uav Continuous Coverage Problem, Taegyun Ha
Theses and Dissertations
The purpose of this research is to develop a method to find an optimal UAV cyclic schedule to provide maximum coverage over a target area to support an ISR mission. The goal is to reach continuous coverage. UAV continuous coverage of a target area is crucial for the success of an ISR mission. Even the smallest coverage gap may jeopardize the success of the mission. Ideally it is desirable to obtain continuous coverage of a target area but the stochastic nature of the problem makes continuous coverage without gaps unlikely. However, it is still possible to obtain a high coverage …
Knowledge Transformation In The United States Air Force Civil Engineer Career Field: A System Dynamics Approach, Gregory J. Ward
Knowledge Transformation In The United States Air Force Civil Engineer Career Field: A System Dynamics Approach, Gregory J. Ward
Theses and Dissertations
Recent operations in Iraq and Afghanistan have brought the level of expeditionary contractors to historically unprecedented levels, altering the work composition for military engineers. The alteration has shifted emphasis from technical knowledge areas toward managerial knowledge associated with supervising the increased number of contractors. This research utilizes System Dynamics modeling to analyze this shift in the United States Air Force Civil Engineer officer career field and resulting transformative effect on career field knowledge levels, both technical and managerial. The model is then tested with multiple external policy adjustments in the areas of career field structure, training, and operating policy. Results …
Development Of A Novel Noise Delivery System For Jp-8 Ototoxicity Studies, John E. Stubbs
Development Of A Novel Noise Delivery System For Jp-8 Ototoxicity Studies, John E. Stubbs
Theses and Dissertations
Numerous chemicals with ototoxic properties may cause hearing loss directly, potentiate noise-induced hearing loss, or produce additive effects. Of interest to the US Air Force are studies showing ototoxic effects of JP-8 jet fuel and its hydrocarbon constituents. The Naval Health Research Center (NHRC) at Wright-Patterson AFB, Ohio, in conjunction with the USAF, is studying the ototoxic effects of JP-8 in rats. The study requires a white noise source that is one octave band wide, centered at 8 kHz frequency, delivered from outside of exposure chambers. Sound pressure levels must be within ± 2 dB at all exposure points within …
Visually Managing Ipsec, Peter J. Dell'accio
Visually Managing Ipsec, Peter J. Dell'accio
Theses and Dissertations
The United States Air Force relies heavily on computer networks to transmit vast amounts of information throughout its organizations and with agencies throughout the Department of Defense. The data take many forms, utilize different protocols, and originate from various platforms and applications. It is not practical to apply security measures specific to individual applications, platforms, and protocols. Internet Protocol Security (IPsec) is a set of protocols designed to secure data traveling over IP networks, including the Internet. By applying security at the network layer of communications, data packets can be secured regardless of what application generated the data or which …
Developing Cyberspace Data Understanding: Using Crisp-Dm For Host-Based Ids Feature Mining, Joseph R. Erskine
Developing Cyberspace Data Understanding: Using Crisp-Dm For Host-Based Ids Feature Mining, Joseph R. Erskine
Theses and Dissertations
Current intrusion detection systems generate a large number of specific alerts, but do not provide actionable information. Many times, these alerts must be analyzed by a network defender, a time consuming and tedious task which can occur hours or days after an attack occurs. Improved understanding of the cyberspace domain can lead to great advancements in Cyberspace situational awareness research and development. This thesis applies the Cross Industry Standard Process for Data Mining (CRISP-DM) to develop an understanding about a host system under attack. Data is generated by launching scans and exploits at a machine outfitted with a set of …
Utilizing The Digital Fingerprint Method For Secure Key Generation, Jennifer C. Anilao
Utilizing The Digital Fingerprint Method For Secure Key Generation, Jennifer C. Anilao
Theses and Dissertations
This research examines a new way to generate an uncloneable secure key by taking advantage of the delay characteristics of individual transistors. The user profiles the circuit to deduce the glitch count of each output line for each number of selectable buffers added to the circuit. The user can then use this information to generate a specific glitch count on each output line, which is passed to an encryption algorithm as its key. The results detail tests of two configurations for adding a selectable amount of buffers into each glitch circuit in order to induce additional delay. One configuration adds …
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 …
Monocular Vision Localization Using A Gimbaled Laser Range Sensor, Don J. Yates
Monocular Vision Localization Using A Gimbaled Laser Range Sensor, Don J. Yates
Theses and Dissertations
There have been great advances in recent years in the area of indoor navigation. Many of these new navigation systems rely on digital images to aid an inertial navigation estimates. The Air Force Institute of Technology (AFIT) has been conducting research in this area for a number of years. The image-aiding techniques are centered around tracking stationary features in order to improve inertial navigation estimates. Previous research has used stereo vision systems or terrain constraints with monocular systems to estimate feature locations. While these methods have shown good results, they do have drawbacks. First, as unmanned exploration vehicles become smaller …
Development Of A Flapping Wing Design Incorporating Shape Memory Alloy Actuation, Jeffrey A. Barrett
Development Of A Flapping Wing Design Incorporating Shape Memory Alloy Actuation, Jeffrey A. Barrett
Theses and Dissertations
This research sought to validate a proof of concept regarding shape memory alloy actuation of a flapping-wing blimp. Specimen wires were subjected to cyclic voltage at increasing frequencies to quantify expected strains. A laser vibrometer captured 2048 sample velocities during single contraction and elongation cycles, and the resulting samples were used to calculate displacements. Displacements were determined ten times for each specimen and frequency to compute averages. Subsequently, a circumventing frame was designed to encase a blimp envelope and provide support for a flapping motion actuation system. Contraction of shape memory wire translated force to the flapping mechanism via bellcranks, …
Conceptual Design Tool For Fuel-Cell Powered Micro Air Vehicles, Paul M. Hrad
Conceptual Design Tool For Fuel-Cell Powered Micro Air Vehicles, Paul M. Hrad
Theses and Dissertations
A conceptual design tool was built to explore power requirements of a hybrid-power system for Micro Air Vehicles (MAVs) comparable in size to the Cooper's Hawk. An inviscid aerodynamic code, Athena Vortex Lattice (AVL), and a motor-propeller analysis code, QPROP, provide overall lift, drag, and thrust data for power-required calculation as functions of many variables to include mass, platform geometry, altitude, velocity, and mission duration. Phoenix Technologies’ Model Center was used to integrate multi-disciplinary components that employ specific power and specific energy of two power sources to determine power system mass required for a designated mission. The tool simulated a …
Islamic Architecture Of Mosques In The Town Of Vushtrri And Its Surrounding, Sami Isufi
Islamic Architecture Of Mosques In The Town Of Vushtrri And Its Surrounding, Sami Isufi
Theses and Dissertations
No abstract provided.
Hiv Services For Refugees In Egypt: An Evaluative Study, Reham Hussain
Hiv Services For Refugees In Egypt: An Evaluative Study, Reham Hussain
Theses and Dissertations
Refugees are a higher risk population for HIV infection due to the absence of proper medical attention and socioeconomic stability during flight and at the country of asylum. Cairo is home to refugees from high conflict regions where sexual violence is prevalent, thus calling for a strong HIV focused care program. This study IS a small scale evaluation of the HIV and AIDS services targeting refugeesâ in Cairo at Refuge-Egyptâ s VCT clinic. This evaluation aims to assess refugeesâ access to preventive methods, testing services as well as the integration within the Egyptian national services. This study takes a qualitative …
Geographic Distribution Of Natural And Anthropogenic Noise In Selected Grand Forks Parks, Erin A. Pederson
Geographic Distribution Of Natural And Anthropogenic Noise In Selected Grand Forks Parks, Erin A. Pederson
Theses and Dissertations
No abstract provided.