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Air Force Institute of Technology

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Articles 961 - 990 of 3057

Full-Text Articles in Physical Sciences and Mathematics

Special Perturbations On The Jetson Tx1 And Tx2 Computers, Tyler M. Moore Mar 2018

Special Perturbations On The Jetson Tx1 And Tx2 Computers, Tyler M. Moore

Theses and Dissertations

Simplified General Perturbations Number 4 (SGP4) has been the traditional algorithm for performing Orbit Determination (OD) onboard orbiting spacecraft. However, the recent rise of high-performance computers with low Size, Weight, and Power (SWAP) factors has provided the opportunity to use Special Perturbations (SP), a more accurate algorithm to perform onboard OD. This research evaluates the most efficient way to implement SP on NVIDIA’s Jetson TX series of integrated Graphical Processing Units (GPUs). An initial serial version was implemented on the Jetson TX1 and TX2's Central Processing Units (CPUs). The runtimes of the initial version are the benchmark that the runtimes …

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Rss-Based Device-Free Passive Detection And Localization Using Home Automation Network Radio Frequencies, Tiffany M. Phan Mar 2018

Rss-Based Device-Free Passive Detection And Localization Using Home Automation Network Radio Frequencies, Tiffany M. Phan

Theses and Dissertations

This research provided a proof of concept for a device-free passive (DfP) system capable of detecting and localizing a target through exploitation of a home automation network’s radio frequency (RF) signals. The system was developed using Insteon devices with a 915 MHz center frequency. Without developer privileges, limitations of the Insteon technology like no intrinsic received signal strength (RSS) field and silent periods between messages were overcome by using software-defined radios to simulate Insteon devices capable of collecting and reporting RSS, and by creating a message generation script and implementing a calibrated filter threshold to reduce silent periods. Evaluation of …

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Near Earth Space Object Detection Utilizing Parallax As Multi-Hypothesis Test Criterion, Joseph C. Tompkins Mar 2018

Near Earth Space Object Detection Utilizing Parallax As Multi-Hypothesis Test Criterion, Joseph C. Tompkins

Theses and Dissertations

The US Strategic Command (USSTRATCOM) operated Space Surveillance Network (SSN) is tasked with Space Situational Awareness (SSA) for the US military. This system is made up of Electro-Optic sensors such as the Space Surveillance Telescope (SST) and Ground-based Electro-Optical Deep Space Surveillance (GEODSS) as well as RADAR based sensors such as the Space Fence. While Lockheed Martin’s Space Fence is very adept at detecting & tracking objects in Low Earth Orbit (LEO) below 3000 Km in height [1], gaps remain in the tracking of Resident Space Objects (RSO’s) in Geosynchronous Orbits (GEO) due to limitations associated with the implementation of …

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Integrity Monitoring For Automated Aerial Refueling: A Stereo Vision Approach, Thomas R. Stuart Mar 2018

Integrity Monitoring For Automated Aerial Refueling: A Stereo Vision Approach, Thomas R. Stuart

Theses and Dissertations

Unmanned aerial vehicles (UAVs) increasingly require the capability to y autonomously in close formation including to facilitate automated aerial refueling (AAR). The availability of relative navigation measurements and navigation integrity are essential to autonomous relative navigation. Due to the potential non-availability of the global positioning system (GPS) during military operations, it is highly desirable that relative navigation can be accomplished without the use of GPS. This paper develops two algorithms designed to provide relative navigation measurements solely from a stereo image pair. These algorithms were developed and analyzed in the context of AAR using a stereo camera system modeling that …

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Text Classification Of Installation Support Contract Topic Models For Category Management, William C. Sevier Mar 2018

Text Classification Of Installation Support Contract Topic Models For Category Management, William C. Sevier

Theses and Dissertations

Air Force Installation Contracting Agency manages nearly 18 percent of total Air Force spend, equating to approximately 57 billion dollars. To improve strategic sourcing, the organization is beginning to categorize installation-support spend and assign accountable portfolio managers to respective spend categories. A critical task in this new strategic environment includes the appropriate categorization of Air Force contracts into newly created, manageable spend categories. It has been recognized that current composite categories have the opportunity to be further distinguished into sub-categories leveraging text analytics on the contract descriptions. Furthermore, upon establishing newly constructed categories, future contracts must be classified into these …

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A Method To Determine The Viability Of Photovoltaic Systems In Various Climate Regions, Joseph A. Applebee Mar 2018

A Method To Determine The Viability Of Photovoltaic Systems In Various Climate Regions, Joseph A. Applebee

Theses and Dissertations

The purpose of this study is to manufacture and disseminate 37 photovoltaic test systems which will be located at various United States Air Force installations worldwide. The Air Force's goals in renewable energy are to determine the potential for systems to aid in promoting resiliency for an installation's energy demands. The test systems are designed to collect climate and power production data from each test site and associated photovoltaic cells. The overall goal of the test system data collection is to determine the correlation between power output of photovoltaic panels and the associated geographic region climate classification. This study does …

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Analysis Of Temperature And Humidity Effects On Horizontal Photovoltaic Panels, Corey J. Booker Mar 2018

Analysis Of Temperature And Humidity Effects On Horizontal Photovoltaic Panels, Corey J. Booker

Theses and Dissertations

The United States Air Force seeks to address power grid vulnerability and bolster energy resilience through the use of renewable energy sources. Air Force Institute of Technology engineers designed and manufactured control systems to monitor power production from the most widely-used silicon-based solar cells at 38 testing locations around the globe spanning the majority of climate types. Researchers conducted multivariate regression analysis to establish a statistical relationship between photovoltaic power output, ambient temperature, and humidity pertaining to monocrystalline and polycrystalline photovoltaic panels. Formulated models first characterized power output globally, then by specific climate type with general inaccuracy. Location-specific models are …

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Optimization Of Geosynchronous Space Situational Awareness Architectures Using Parallel Computation, Michael S. Felten Mar 2018

Optimization Of Geosynchronous Space Situational Awareness Architectures Using Parallel Computation, Michael S. Felten

Theses and Dissertations

Improving Space Situational Awareness (SSA) remains one of the DoD’s top priorities. Current research at the Air Force Institute of Technology (AFIT) has shown that modeling and simulation of Geosynchronous Earth Orbit (GEO) SSA architectures can identify optimal combinations of ground and space-based sensors. This thesis extends previous research by expanding design boundaries and refining the methodology. A genetic algorithm examined this increased trade space containing 1022 possible architectures. Experimental trials that would have taken over 100 years on a desktop computer were completed in weeks using a high-performance computer containing over 125,000 cores. The results of the optimizer clearly …

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Characterization Of The Effects Of Heavy Charged Particle Exposure On The Radiation Resistant Bacterium Deinococcus Radiodurans, Todd A. Bryant Mar 2018

Characterization Of The Effects Of Heavy Charged Particle Exposure On The Radiation Resistant Bacterium Deinococcus Radiodurans, Todd A. Bryant

Theses and Dissertations

Although not an extremophile, Deinococcus radiodurans has proven to have exceptional resistance to ionizing radiation, specifically via gamma and X-ray photons. To date, no known experiments have bombarded the bacterium with charged particles larger than hydrogen. This study explored the effects on the organism’s ability to survive high linear energy transfer heavy-charged particle exposures of oxygen ions. It also investigated the effects of low linear energy transfer ultraviolet radiation on various mutants. Two uvrB mutants were created to ascertain the importance of the gene in single-strand break repair following gamma irradiation and two recF mutants were created to explore the …

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A New Analysis Of The Gálvez-Davison Index For Convective Forecasts In Northern Africa, Gabriel D. Donndelinger Mar 2018

A New Analysis Of The Gálvez-Davison Index For Convective Forecasts In Northern Africa, Gabriel D. Donndelinger

Theses and Dissertations

Severe wind gusts and thunderstorms have been difficult to forecast in Africa. Traditional convective forecast tools (e.g. Total Totals Index, Lifted Index, K Index (KI) and Convective Available Potential Energy) do not accurately portray potential for thunderstorms in Africa. This research effort used the Gálvez-Davison Index (GDI), a convective index created for the tropics, and assess its applicability to northern Africa. GDI was produced for the Caribbean and Central America, and utilized temperature, moisture, mid-level stability, dry air entrainment and an elevation factor to calculate convective potential. In this research, GDI and KI were calculated using Global Forecast System (GFS) …

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Passive Radiolocation Of Ieee 802.11 Emitters Using Directional Antennae, Bradford E. Law Mar 2018

Passive Radiolocation Of Ieee 802.11 Emitters Using Directional Antennae, Bradford E. Law

Theses and Dissertations

Low-cost commodity hardware and cheaper, more capable consumer-grade drones make the threat of home-made, inexpensive drone-mounted wireless attack platforms (DWAPs) greater than ever. Fences and physical security do little to impede a drone from approaching private, commercial, or government wireless access points (WAPs) and conducting wireless attacks. At the same time, unmanned aerial vehicles (UAVs) present a valuable tool for network defenders conducting site surveys and emulating threats. These platforms present near-term dangers and opportunities for corporations and governments. Despite the vast leaps in technology these capabilities represent, UAVs are noisy and consequently difficult to conceal as they approach a …

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Outlier Classification Criterion For Multivariate Cyber Anomaly Detection, Alexander M. Trigo Mar 2018

Outlier Classification Criterion For Multivariate Cyber Anomaly Detection, Alexander M. Trigo

Theses and Dissertations

Every day, intrusion detection systems catalogue millions of unsupervised data entries. This represents a “big data” problem for research sponsors within the Department of Defense. In a first response to this issue, raw data capture was transformed into usable vectors and an array of multivariate techniques implemented to detect potential outliers. This research expands and refines these techniques by implementing a Chi-Square Q-Q plot-based classification criteria for outlier detection. This methodology has been implemented into an R-based programming solution that allows for a refined and semi-automated user experience for intelligence analysts. Moreover, two case analyses are performed that illustrate how …

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Quantifying Permafrost Extent, Condition, And Degradation Rates At Department Of Defense Installations In The Arctic, Christopher A. J. Edlund Mar 2018

Quantifying Permafrost Extent, Condition, And Degradation Rates At Department Of Defense Installations In The Arctic, Christopher A. J. Edlund

Theses and Dissertations

The DoD is planning over $500M in military construction on Eielson Air Force Base (AFB) within the next three years. This construction program will expand the footprint of facilities and change parts of the storm water management scheme, which may have second order effects on the underlying permafrost layer. These changes in permafrost will drive engineering decision making at local and regional levels, and help shape the overall strategy for military readiness in the Arctic. Little site-specific knowledge exists on the human caused effects to permafrost at this location. In 2016, the permafrost degradation rates at Eielson AFB were modeled …

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An Analysis Of The Estimate At Complete For Department Of Defense Contracts, Deborah B. Kim Mar 2018

An Analysis Of The Estimate At Complete For Department Of Defense Contracts, Deborah B. Kim

Theses and Dissertations

When contractors provide timely and reliable information on the status of a contract, both contractors and government program offices can provide an accurate estimate of a contract’s completion costs. This research shows that the cumulative cost performance indices provided by contractors and program offices are high and less accurate than those of previous years and/or that a significant amount of ACWP is being documented in the final portion of a contract. The high performance indices resulted in EACs that were low-balled during the majority of a contract’s life which shows a need to improve the use of EVM metrics for …

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Shortest Path Across Stochastic Network With Correlated Random Arcs, Stephanie M. Boone Mar 2018

Shortest Path Across Stochastic Network With Correlated Random Arcs, Stephanie M. Boone

Theses and Dissertations

This paper introduces a new approach to identify the shortest path across a stochastic network with correlated random arcs utilizing nonparametric samples of arc lengths. This approach is applied to find optimal aircraft routes that minimize expected fuel consumption for a given airspeed utilizing predicted wind output from NWP ensemble models. Results from this new methodology are then compared to the current fuel minimization route planning method that utilizes deterministic NWP wind data for arc lengths. Comparisons are also made to other previously proposed alternative fuel minimization methodologies that utilize mean and median wind data calculated from NWP ensemble wind …

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Characterization Of Silicon Ion Exposure On Deinococcus Radiodurans, Richard F. Daughtry Mar 2018

Characterization Of Silicon Ion Exposure On Deinococcus Radiodurans, Richard F. Daughtry

Theses and Dissertations

Deinococcus radiodurans is a robust bacterium that is known for its extraordinary resistance to ionizing radiation. In general, many of the investigations of this bacterium's resistance have revolved around low linear energy transfer radiation, such as gamma and electron radiation. This study explored Deinococcus radiodurans's ability to survive high linear energy transfer radiation, specifically proton and neutron radiation. Deinococcus radiodurans was dehydrated to reduce the effects of low linear energy transfer radiation. The bacteria were exposed to both neutron and proton radiation of varying amounts and rehydrated. The resulting colonies were counted and compared to colonies of non-irradiated control samples …

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A Comparison Of High Frequency Angle Of Arrival And Ionosonde Data During A Traveling Ionospheric Disturbance, Kalen L. Knippling Mar 2018

A Comparison Of High Frequency Angle Of Arrival And Ionosonde Data During A Traveling Ionospheric Disturbance, Kalen L. Knippling

Theses and Dissertations

High Frequency (HF) geolocation techniques are commonly used to track the source of uncooperative HF emitters. A traveling ionospheric disturbance (TID) makes geolocation particularly difficult due to large perturbations in the local ionospheric electron density profile. Angle of Arrival (AoA) and ionosonde virtual height measurements collected at White Sands Missile Range, New Mexico in January 2014, are analyzed during a medium scale traveling ionospheric disturbance. TID characteristics are extracted from the measurements, and a comparison between the data sets is per- formed to provide a measure of correlation as a function of distance and time between the ionosonde and AoA …

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Wall-Modeled Large Eddy Simulation Of A Three-Dimensional Shock-Boundary Layer Interaction, Nicholas J. Marco Mar 2018

Wall-Modeled Large Eddy Simulation Of A Three-Dimensional Shock-Boundary Layer Interaction, Nicholas J. Marco

Theses and Dissertations

The direct simulation of turbulent flows is prohibitive at high Reynolds numbers; thus, methods such as RANS and LES are used. However, these methods still require a large number of cells near a solid boundary. To circumvent this issue, a Wall-Modeled Large Eddy Simulation (WM-LES) can be used. Of interest is how these wall models perform in comparison to a Wall-Resolved Large Eddy Simulation (WR-LES) and experimental results of a shock turbulent boundary layer interactions (STBLI) and specifically, whether equilibrium wall models are sufficient to resolve the oscillatory and hence non-equilibrium nature of these flows or whether a non-equilibrium model …

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Pseudo Linear Hall Effect Thruster Characterization Through Potential, Magnetic, And Optical Measurements, Braeden A. Sheets Mar 2018

Pseudo Linear Hall Effect Thruster Characterization Through Potential, Magnetic, And Optical Measurements, Braeden A. Sheets

Theses and Dissertations

Electric propulsion systems are a more mass efficient method for providing a change in velocity, ΔV, to on-orbit spacecraft, than their chemical counterparts. In comparison, electric systems generally have a much higher specific impulse, Isp, than chemical systems. One option within the realm of electric propulsion is Hall Effect Thrusters, which have moderately high specific impulse values. From their advent in the 1960s, Hall Effect Thrusters have been used for orbit station keeping, attitude control, and orbit transfer. Although the discharge cavity is conventionally circular, pseudo-linear or racetrack shaped cavities have been developed. Even though Hall thrusters have decades of …

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Estimating Defensive Cyber Operator Decision Confidence, Markus M. Borneman Mar 2018

Estimating Defensive Cyber Operator Decision Confidence, Markus M. Borneman

Theses and Dissertations

As technology continues to advance the domain of cyber defense, signature and heuristic detection mechanisms continue to require human operators to make judgements about the correctness of machine decisions. Human cyber defense operators rely on their experience, expertise, and understanding of network security, when conducting cyber-based investigations, in order to detect and respond to cyber alerts. Ever growing quantities of cyber alerts and network traffic, coupled with systemic manpower issues, mean no one has the time to review or change decisions made by operators. Since these cyber alert decisions ultimately do not get reviewed again, an inaccurate decision could cause …

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Progressive Network Deployment, Performance, And Control With Software-Defined Networking, Daniel J. Casey Mar 2018

Progressive Network Deployment, Performance, And Control With Software-Defined Networking, Daniel J. Casey

Theses and Dissertations

The inflexible nature of traditional computer networks has led to tightly-integrated systems that are inherently difficult to manage and secure. New designs move low-level network control into software creating software-defined networks (SDN). Augmenting an existing network with these enhancements can be expensive and complex. This research investigates solutions to these problems. It is hypothesized that an add-on device, or "shim" could be used to make a traditional switch behave as an OpenFlow SDN switch while maintaining reasonable performance. A design prototype is found to cause approximately 1.5% reduction in throughput for one ow and less than double increase in latency, …

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Modeling A Space-Based Quantum Link, Alexander W. Duchane Mar 2018

Modeling A Space-Based Quantum Link, Alexander W. Duchane

Theses and Dissertations

Quantum sources and single photon detectors have improved, allowing quantum algorithms for communication, encryption, computing, and sensing to transition from theory and small-scale laboratory experiments to field experiments. One such quantum algorithm, Quantum Key Distribution, uses optical pulses to generate shared random bit strings between two locations. These shared bit strings can be turned into encryption keys to be used as a one-time-pad or integrated with symmetric encryption techniques such as the Advanced Encryption Standard. This method of key generation and encryption is resistant to future advances in quantum computing which significantly degrade the effectiveness of current asymmetric key sharing …

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Assured Android Execution Environments, Brandon P. Froberg Mar 2018

Assured Android Execution Environments, Brandon P. Froberg

Theses and Dissertations

Current cybersecurity best practices, techniques, tactics and procedures are insufficient to ensure the protection of Android systems. Software tools leveraging formal methods use mathematical means to assure both a design and implementation for a system and these methods can be used to provide security assurances. The goal of this research is to determine methods of assuring isolation when executing Android software in a contained environment. Specifically, this research demonstrates security properties relevant to Android software containers can be formally captured and validated, and that an implementation can be formally verified to satisfy a corresponding specification. A three-stage methodology called "The …

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Mitigating The Effects Of Boom Occlusion On Automated Aerial Refueling Through Shadow Volumes, Zachary C. Paulson Mar 2018

Mitigating The Effects Of Boom Occlusion On Automated Aerial Refueling Through Shadow Volumes, Zachary C. Paulson

Theses and Dissertations

In flight refueling of Unmanned Aerial Vehicles (UAVs) is critical to the United States Air Force (USAF). However, the large communication latency between a ground-based operator and his/her remote UAV makes docking with a refueling tanker unsafe. This latency may be mitigated by leveraging a tanker-centric stereo vision system. The vision system observes and computes an approaching receiver's relative position and orientation offering a low-latency, high frequency docking solution. Unfortunately, the boom -- an articulated refueling arm responsible for physically pumping fuel into the receiver -- occludes large portions of the receiver especially as the receiver approaches and docks with …

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Stereo Vision: A Comparison Of Synthetic Imagery Vs. Real World Imagery For The Automated Aerial Refueling Problem, Nicholas J. Seydel Mar 2018

Stereo Vision: A Comparison Of Synthetic Imagery Vs. Real World Imagery For The Automated Aerial Refueling Problem, Nicholas J. Seydel

Theses and Dissertations

Missions using unmanned aerial vehicles have increased in the past decade. Currently, there is no way to refuel these aircraft. Accomplishing automated aerial refueling can be made possible using the stereo vision system on a tanker. Real world experiments for the automated aerial refueling problem are expensive and time consuming. Currently, simulations performed in a virtual world have shown promising results using computer vision. It is possible to use the virtual world as a substitute environment for the real world. This research compares the performance of stereo vision algorithms on synthetic and real world imagery.

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Satellite Communications In The V And W Band: Tropospheric Effects, Bertus A. Shelters Mar 2018

Satellite Communications In The V And W Band: Tropospheric Effects, Bertus A. Shelters

Theses and Dissertations

An investigation into the use of Weather Cubes compiled by the atmospheric characterization package, Laser Environmental Effects Definition and Reference (LEEDR), to develop accurate, long-term attenuation statistics for link-budget analysis is presented. A Weather Cube is a three-dimensional mesh of numerical weather prediction (NWP) data plus LEEDR calculations that allows for the quantification of rain, cloud, aerosol, and molecular effects at any UV to RF wavelength on any path contained within the cube. The development of this methodology is motivated by the potential use of V (40-75 GHz) and W (75-110 GHz) band frequencies for the satellite communication application, as …

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The Application Of Text Mining And Data Visualization Techniques To Textual Corpus Exploration, Jeffrey R. Smith Jr. Mar 2018

The Application Of Text Mining And Data Visualization Techniques To Textual Corpus Exploration, Jeffrey R. Smith Jr.

Theses and Dissertations

Unstructured data in the digital universe is growing rapidly and shows no evidence of slowing anytime soon. With the acceleration of growth in digital data being generated and stored on the World Wide Web, the prospect of information overload is much more prevalent now than it has been in the past. As a preemptive analytic measure, organizations across many industries have begun implementing text mining techniques to analyze such large sources of unstructured data. Utilizing various text mining techniques such as n -gram analysis, document and term frequency analysis, correlation analysis, and topic modeling methodologies, this research seeks to develop …

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Analysis Of A Voting Method For Ranking Network Centrality Measures On A Node-Aligned Multiplex Network, Kyle S. Wilkinson Mar 2018

Analysis Of A Voting Method For Ranking Network Centrality Measures On A Node-Aligned Multiplex Network, Kyle S. Wilkinson

Theses and Dissertations

Identifying relevant actors using information gleaned from multiple networks is a key goal within the context of human aspects of military operations. The application of a voting theory methodology for determining nodes of critical importance—in ranked order of importance—for a node-aligned multiplex network is demonstrated. Both statistical and qualitative analyses on the differences of ranking outcomes under this methodology is provided. As a corollary, a multilayer network reduction algorithm is investigated within the context of the proposed ranking methodology. The application of the methodology detailed in this thesis will allow meaningful rankings of relevant actors to be produced on a …

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Lightning Prediction Using Artificial Neural Networks And Electric Field Mill Data, Daniel E. Hill Mar 2018

Lightning Prediction Using Artificial Neural Networks And Electric Field Mill Data, Daniel E. Hill

Theses and Dissertations

Electric Field Mills (EFMs) located in the region surrounding Cape Canaveral record the electrification of the atmosphere near them. Research studying how these sensors could improve lightning warnings has had mixed results. This paper used a Convolutional Recurrent Neural Network (CRNN) and data from 30 EFMs from May-July of 2012-2016. The mean was calculated for every 60 second period and 30 minutes of this summarized data was used to create a lightning prediction with a warning period of 15 minutes. This method achieved a True Positive Rate (TPR) of 77.6%, a False Positive Rate (FPR) of 8.3%, a False Discovery …

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Using An Astrophysical Model To Characterize Nuclear Dust, Anita N. Dunsmore Mar 2018

Using An Astrophysical Model To Characterize Nuclear Dust, Anita N. Dunsmore

Theses and Dissertations

Dust clouds resulting from nuclear explosions are complex phenomena, and knowledge on how they form is lacking. Noting the similarities between supernovae and nuclear explosions led to the concept of modeling a nuclear dust cloud using a supernova simulation. MOCASSIN uses a Monte Carlo approach to model photons traveling through a dust cloud, allowing the cloud's characteristics to be discovered by comparing an observed spectrum to a calculated one and then changing input values to make the spectra match. Data files describing two nuclear fireballs of varying yields were created and analyzed using MOCASSIN, but yielded zero energy spectra. After …

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