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Articles 39031 - 39060 of 196126

Full-Text Articles in Engineering

Securing Infiniband Networks With End-Point Encryption, Noah B. Diamond Mar 2022

Securing Infiniband Networks With End-Point Encryption, Noah B. Diamond

Theses and Dissertations

The NVIDIA-Mellanox Bluefield-2 is a 100 Gbps high-performance network interface which offers hardware offload and acceleration features that can operate directly on network traffic without routine involvement from the ARM CPU. This allows the ARM multi-core CPU to orchestrate the hardware to perform operations on both Ethernet and RDMA traffic at high rates rather than processing all the traffic directly. A testbed called TNAP was created for performance testing and a MiTM verification process called MiTMVMP is used to ensure proper network configuration. The hardware accelerators of the Bluefield-2 support a throughput of nearly 86 Gbps when using IPsec to …

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Uav Payload Identification With Acoustic Emissions And Cell Phone Devices, Hunter G. Doster Mar 2022

Uav Payload Identification With Acoustic Emissions And Cell Phone Devices, Hunter G. Doster

Theses and Dissertations

The growing presence of Unmanned Aerial Vehicle (UAV) brings new threats to the civilian and military front. In response, the Department of Defense (DoD) is developing many drone detection systems. Current systems use Radio Detection and Ranging (RADAR), Light Detection and Ranging (LiDAR), and Radio Frequency (RF). Although useful, these technologies are becoming easier to spoof every year, and some are limited to line of sight. Acoustic emissions are a unique quality all drones emit. Acoustics are difficult to spoof and do not require line of sight for detection. This research expands the research field of study by creating HurtzHunter, …

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Exploiting The Iot Through Network-Based Covert Channels, Kyle S. Harris Mar 2022

Exploiting The Iot Through Network-Based Covert Channels, Kyle S. Harris

Theses and Dissertations

Information leaks are a top concern to industry and government leaders. The IoT is a technology capable of sensing real-world events. A method for exfiltrating data from these devices is by covert channel. This research designs a novel IoT CTC without the need for inter-packet delays to encode data. Instead, it encodes data within preexisting network information, namely ports or addresses. Additionally, the CTC can be implemented in two different modes: Stealth and Bandwidth. Performance is measured using throughput and detectability. The Stealth methods mimic legitimate traffic captures while the Bandwidth methods forgo this approach for maximum throughput. Detection results …

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Thermal Considerations For Film Cooling Materials With Anisotropic Thermal Conductivity, Carol E. Bryant Mar 2022

Thermal Considerations For Film Cooling Materials With Anisotropic Thermal Conductivity, Carol E. Bryant

Theses and Dissertations

Higher performance requirements and reduced core sizes are driving increases in turbine inlet temperature in gas turbine engines, surpassing the melting point of advanced materials. Newer materials, such as composites, are being introduced into the hot sections of gas turbine engines. Components in the hot section use film cooling to prevent melting. One unique aspect of some high-temperature composites is they have a bulk anisotropic thermal conductivity, therefore heat flow differs relative to traditional metallic components. Film cooling designs can be revolutionized by leveraging anisotropy in high-temperature materials. The purpose of this research is to examine thermal considerations for using …

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Training Logic And Random Forest Models To Predict It Spending, Jacob P. Batt Mar 2022

Training Logic And Random Forest Models To Predict It Spending, Jacob P. Batt

Theses and Dissertations

The Air Force must modernize, but the distribution of funds for technology remains as tight as ever. To this end, the Air Force Audit Agency is looking to utilize machine learning techniques to enhance their capabilities. This research explores Logistic Regression and Random Forest modeling to streamline data collection and cost classification. The final Logistic Regression model identified 4 significant attributes out of the 36 given and was 85 accurate in predicting whether a purchase amount was over or under $10,000. To expand beyond binary classification, a six-category classification Random Forest model was developed. It identified 6 significant attributes and …

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Military Personnel Flight Customer Wait Time Reduction Model Using Simulation, Nicholas C. Anderson Mar 2022

Military Personnel Flight Customer Wait Time Reduction Model Using Simulation, Nicholas C. Anderson

Theses and Dissertations

Customers at Military Personnel Flights (MPFs) have been experiencing long wait times. These customers are typically employees of the United States Air Force and every moment spent waiting for service is a moment they are away from their actual jobs. By reducing the mean wait time of MPF customers, manhours can be saved and customer complaints may be alleviated. This research uses data collected from an MPF to build a discrete-event simulation model of an MPF. A full factorial experimental design was conducted in the model using five factors. The factors included the total number of employees, the total number …

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Evaluating The Military Medical Evacuation Dispatching And Delivery Problem Via Simulation And Self-Exciting Hawkes Process, Virbon B. Frial Mar 2022

Evaluating The Military Medical Evacuation Dispatching And Delivery Problem Via Simulation And Self-Exciting Hawkes Process, Virbon B. Frial

Theses and Dissertations

The location, allocation, and utilization of military medical evacuation (MEDEVAC) resources significantly impact the quality and timeliness of medical care to injured troops. In 2009, Secretary of Defense Robert Gates introduced the Golden Hour mandate that entails the evacuation of critically-injured troops to military treatment facilities (MTFs) within an hour to prevent further complications. To develop high-quality policies that improve MEDEVAC system performance, several papers in the current literature assume that MTFs have both the capacity and capability of treating any patient, regardless of the type of injury. However, these assumptions are unrealistic when conducting high-intensity operations. While acknowledging MTF …

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Applications Of A Lightning Proxy To Generate Synthetic Lightning For Use In Physics-Based Image-Chain Models, Bryan G. Castro Mar 2022

Applications Of A Lightning Proxy To Generate Synthetic Lightning For Use In Physics-Based Image-Chain Models, Bryan G. Castro

Theses and Dissertations

A method of generating synthetic lightning through the use of a convective available potential energy (CAPE) times precipitation rate (P) proxy is applied over three distinct climatological zones of the world for a single warm season: central and southern AZ of the United States, central Cuba, and North Korea. Global Forecast System (GFS) 0.25° by 0.25° forecast data for June, July, and August of 2019 is used to provide 6-hourly CAPE and precipitation rate, while Global Lightning Dataset (GLD360) data for the period 2016 to 2020 is used to provide observed lightning strokes. A five-year lightning climatology study is conducted …

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Approximate Dynamic Programming For An Unmanned Aerial Vehicle Routing Problem With Obstacles And Stochastic Target Arrivals, Kassie M. Gurnell Mar 2022

Approximate Dynamic Programming For An Unmanned Aerial Vehicle Routing Problem With Obstacles And Stochastic Target Arrivals, Kassie M. Gurnell

Theses and Dissertations

The United States Air Force is investing in artificial intelligence (AI) to speed analysis in efforts to modernize the use of autonomous unmanned combat aerial vehicles (AUCAVs) in strike coordination and reconnaissance (SCAR) missions. This research examines an AUCAVs ability to execute target strikes and provide reconnaissance in a SCAR mission. An orienteering problem is formulated as anMarkov decision process (MDP) model wherein a single AUCAV must optimize its target route to aid in eliminating time-sensitive targets and collect imagery of requested named areas of interest while evading surface-to-air missile (SAM) battery threats imposed as obstacles. The AUCAV adjusts its …

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A New Approach To Career Field Matching For Commissioning Air Force Cadets, Daniel Griffen Laird Mar 2022

A New Approach To Career Field Matching For Commissioning Air Force Cadets, Daniel Griffen Laird

Theses and Dissertations

The current method of assigning graduating cadets from the United States Air Force Academy and Reserve Officers' Training Corps (ROTC) detachments to their career fields uses an integer programming model to maximize \global" Air Force utility, subject to several Air Force-defined constraints. This utility evaluates the positive benefit of assigning a certain cadet to a certain career field. This paper discusses the issues with such a model, as well as presents a new, more refined approach to the problem. Rather than provide a one-size-fits-all formulation of this particular assignment problem, a Value-Focused Thinking (VFT) framework is applied, in conjunction with …

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Narrative Analysis Of Open-Source Social Media Activity In The Indopacom Aor, Aaron K. Glenn Mar 2022

Narrative Analysis Of Open-Source Social Media Activity In The Indopacom Aor, Aaron K. Glenn

Theses and Dissertations

Emotion classification can be a powerful tool to derive narratives from social media data. Recurrent Neural Networks (RNN) can meet or exceed the performance of state-of-the-art traditional machine learning techniques using exclusively open-source data and models. Specifically, these results show that RNN variants can produce more than an 8% gain in accuracy in comparison to Logistic Regression and SVM techniques and a 15% gain over Random Forest when using FastText embeddings. This research found a statistical significance in the performance of a single layer Bi-directional Long Short-Term Memory (Bi-LSTM) model over a 2-layer stacked Bi-LSTM model. This research also found …

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An Exploratory Analysis Of Time Series Econometric Data For Retention Forecasting Using Deep Learning, John C. O'Donnell Mar 2022

An Exploratory Analysis Of Time Series Econometric Data For Retention Forecasting Using Deep Learning, John C. O'Donnell

Theses and Dissertations

Officer retention in the Air Force has been researched many times in an attempt to better predict the personnel needs of the Air Force for the future. There has been previous work done in regards to specific AFSCs and how their retention compares to specific yet similar private sector jobs. This study considers different econometric time series statistics as a feature space and an average Air Force officer separation rate as the response variable for the multivariate time series analysis deep learning techniques. The econometric indicators used in this study are New Business Formations, New Durable Good Orders, and the …

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Multiagent Routing Problem With Dynamic Target Arrivals Solved Via Approximate Dynamic Programming, Andrew E. Mogan Mar 2022

Multiagent Routing Problem With Dynamic Target Arrivals Solved Via Approximate Dynamic Programming, Andrew E. Mogan

Theses and Dissertations

This research formulates and solves the multiagent routing problem with dynamic target arrivals (MRP-DTA), a stochastic system wherein a team of autonomous unmanned aerial vehicles (AUAVs) executes a strike coordination and reconnaissance (SCAR) mission against a notional adversary. Dynamic target arrivals that occur during the mission present the team of AUAVs with a sequential decision-making process which we model via a Markov Decision Process (MDP). To combat the curse of dimensionality, we construct and implement a hybrid approximate dynamic programming (ADP) algorithmic framework that employs a parametric cost function approximation (CFA) which augments a direct lookahead (DLA) model via a …

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Estimating Atmospheric Turbulence Within A Short Exposure Frame Selection Algorithm, Aaron J. Deluca Mar 2022

Estimating Atmospheric Turbulence Within A Short Exposure Frame Selection Algorithm, Aaron J. Deluca

Theses and Dissertations

Space is becoming an increasingly crowded domain. As it becomes more congested, the ability to accurately detect and track objects, both natural and man-made, becomes more and more important. Having an accurate space surveillance network allows us to protect our own space assets while also maintaining awareness of foreign space assets and threats to our satellites such as debris and small meteorites. This means that the ability to detect small, dim objects is key to being able to protect our space assets. This thesis will seek to expand on and improve certain existing space object detection techniques and algorithms.

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Relative Magnetic Position And Rotation Sensor Assisted Dual-Foot Pedestrian Dead Reckoning, Jenario Y. Johnson Mar 2022

Relative Magnetic Position And Rotation Sensor Assisted Dual-Foot Pedestrian Dead Reckoning, Jenario Y. Johnson

Theses and Dissertations

The use of wearable foot-based inertial measurement units (IMUs) incorporated in a navigation system can address the problem of single-person location tracking in situations and environments where GPS signals may be unavailable or inconsistent. This Pedestrian Dead Reckoning (PDR) approach enables standalone personal tracking. A notable solution involves using inertial measurement units (IMUs) in a filter to apply zero-velocity updates to a Kalman filter to get a position solution. This paper continues on the path of the former method by investigating the feasibility of PDR using a pair of low cost IMUs along with a pair of relative position and …

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Comparison Of Lightning Warning Radii Distributions, Michael M. Maestas Mar 2022

Comparison Of Lightning Warning Radii Distributions, Michael M. Maestas

Theses and Dissertations

Previous research investigating lightning warning radii about the Cape Canaveral space launch facilities have focused on reducing these radii from either 5 nautical miles (NM) to 4 NM or from 6 NM to 5 NM depending on the structures being protected. Some of these findings have suggested the possibility of both a seasonal difference (warm versus cold) and lightning detection events (cloud-to-ground lightning (CG) or total lightning (TL)) impacting these radii and associated risk levels. Utilizing the 2017-2020 data provided by the 45th Weather Squadron at Patrick Space Force Base via the Mesoscale Eastern Range Lightning Information System (MERLIN), this …

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Determination Of Nonlinear Optical Properties For Gallium Arsenide Phosphide Ternary Compounds And For Tin Thiohypodiphosphate, Peter F. Norris Mar 2022

Determination Of Nonlinear Optical Properties For Gallium Arsenide Phosphide Ternary Compounds And For Tin Thiohypodiphosphate, Peter F. Norris

Theses and Dissertations

The Department of Defense and the commercial sector rely on coherent light sources to emit light that transmits through the atmosphere. Nonlinear optical effects in crystalline materials can be used to generate the laser waves, but certain nonlinear effects negatively impact the performance of laser generating materials. This thesis focuses on characterizing nonlinear optical properties for gallium arsenide phosphide ternary compounds and for tin thiohypodiphosphate. The Maker Fringe experiment is used to determine the d-coefficients of the materials, which describe the magnitude of the nonlinear response of the material. The Z-Scan experiment is used to calculate the nonlinear refractive …

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Assessing The United States Foreign Assistance Activities Impact On Violent Conflicts, Daniel F. Feze Mar 2022

Assessing The United States Foreign Assistance Activities Impact On Violent Conflicts, Daniel F. Feze

Theses and Dissertations

The Global Fragility Act, H.R.2116 116th Cong. (2019), “directs the Department of State to establish the interagency Global Fragility Initiative to stabilize conflict-affected areas and prevent violence globally, and establishes funds to support such efforts”. The United States Agency for International Development (USAID) has identified deteriorating economies, weak or illegitimate political institutions, and competition over natural resources as causes of violence, extremism and instability (USAID, 2021). The agency gives priority to mitigating the causes and consequences of violent conflicts, instability and extremism and funds programs and activities to accomplish that (USAID, 2021). With this study, we aim to quantitatively assess …

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Analysis Of Twitter Networks To Aid Open Source Intelligence Capabilities: A Multilayer Network Approach, Austin P. Logan Mar 2022

Analysis Of Twitter Networks To Aid Open Source Intelligence Capabilities: A Multilayer Network Approach, Austin P. Logan

Theses and Dissertations

Open Source Intelligence using social media is a practice which gives military intelligence analysts a window into the thoughts and minds of an online population. Using Social Network Analysis, user interactions on Twitter will be modeled as a weighted and directed network. Topic modeling through Latent Dirichlet Allocation uncovers the topics of discussion in Tweets and is then integrated into a multi-layer network which allows users to be connected to the conversations with which they have participated. Influential users in this network as well as highly connected groups of individuals are then discovered to paint a picture for intelligence analysts …

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Bayesian Convolutional Neural Network With Prediction Smoothing And Adversarial Class Thresholds, Noah M. Miller Mar 2022

Bayesian Convolutional Neural Network With Prediction Smoothing And Adversarial Class Thresholds, Noah M. Miller

Theses and Dissertations

Using convolutional neural networks (CNNs) for image classification for each frame in a video is a very common technique. Unfortunately, CNNs are very brittle and have a tendency to be over confident in their predictions. This can lead to what we will refer to as “flickering,” which is when the predictions between frames jump back and forth between classes. In this paper, new methods are proposed to combat these shortcomings. This paper utilizes a Bayesian CNN which allows for a distribution of outputs on each data point instead of just a point estimate. These distributions are then smoothed over multiple …

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Examining The Relationship Between An Aging Workforce And Logistics Performance Indicators, Daniel Parkhill Mar 2022

Examining The Relationship Between An Aging Workforce And Logistics Performance Indicators, Daniel Parkhill

Theses and Dissertations

In the United States, 10,000 baby boomers turn 65 every day. The subsequent generation born between 1965 and 1976 is significantly smaller, referred to as the baby bust. As a result, this causes a talent shortage as Baby Boomers retire, leaving a workforce gap which the subsequent generation is not large enough to fill. This issue also has been recognized as a potential problem in the logistics community of the United States Air Force. The purpose of this study is to examine the impact of workers age on key logistics performance indicators (LPIs) such as aircraft availability, product flow days, …

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Simultaneous Actuation And Sensing Of Electrostatic Mems, Jacob E. Song Mar 2022

Simultaneous Actuation And Sensing Of Electrostatic Mems, Jacob E. Song

Theses and Dissertations

Micro-Electro-Mechanical Systems (MEMS) are devices that play important roles of sensing and actuation in many different industries including automation, electronics, medical, communications, and defense. In order to make full use of these devices, it is important to understand the peripherals that enable these devices. Simultaneous actuation and control of MEMS devices is an important area of research as it enables feedback control of these device and allows devices to maintain performance as devices depreciate over their lifetime. The aim of this thesis is to perform a design space analysis on an electrostatic MEMS simultaneous actuation and sensing circuit that is …

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Considering Dds In The Domain Of Dis - Pros And Cons, Nathaniel R. Peck Mar 2022

Considering Dds In The Domain Of Dis - Pros And Cons, Nathaniel R. Peck

Theses and Dissertations

DIS is a legacy IEEE standard for defining and structuring PDUs in large scale distributed wargames. Although the standard specifies various QoS appropriate for certain PDUs, a one-size-fits-all transport strategy is traditionally employed via UDP. Since the inception of DIS, the OMG has produced a standard for a DDS which has been implemented by several middleware vendors. DDS middleware offers an abstraction for network communications that allows applications and developers to easily employ configurable QoS by topic. Adoption and use of these QoS in DIS applications may introduce greater compliance with the IEEE standard and enrich the service features available …

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Covariance Analysis For Multi-Source Navigation Architecture, Tristan T. Williams Mar 2022

Covariance Analysis For Multi-Source Navigation Architecture, Tristan T. Williams

Theses and Dissertations

Currently, analysis on navigation systems can be slow and computationally expensive using Monte Carlo approaches. Covariance analysis is a tool that can return trade space analysis results promptly and can be computationally reasonable. This research aims to create a covariance analysis tool in a new navigation framework architecture, PntOS. The creation of this covariance tool is explained in coordination with the tool being used in a few different navigation scenarios with the results. These scenarios include a Doppler LiDAR velocity sensor and magnetic anomaly navigation.

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Team Air Combat Using Model-Based Reinforcement Learning, David A. Mottice Mar 2022

Team Air Combat Using Model-Based Reinforcement Learning, David A. Mottice

Theses and Dissertations

We formulate the first generalized air combat maneuvering problem (ACMP), called the MvN ACMP, wherein M friendly AUCAVs engage against N enemy AUCAVs, developing a Markov decision process (MDP) model to control the team of M Blue AUCAVs. The MDP model leverages a 5-degree-of-freedom aircraft state transition model and formulates a directed energy weapon capability. Instead, a model-based reinforcement learning approach is adopted wherein an approximate policy iteration algorithmic strategy is implemented to attain high-quality approximate policies relative to a high performing benchmark policy. The ADP algorithm utilizes a multi-layer neural network for the value function approximation regression mechanism. One-versus-one …

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Evaluation Of The Armas-Som Framework With Real Data, Brandon M. Blakely Mar 2022

Evaluation Of The Armas-Som Framework With Real Data, Brandon M. Blakely

Theses and Dissertations

The ARMAS framework was created with the goal of developing a framework for all-source sensors which is able to combine detection, identification, calibration, model selection, and independent evaluation into a single system. Stable Observability Monitoring (SOM), augments the original ARMAS framework by enabling ARMAS to detect whether or not its Fault Detection and Exclusion (FDE) capabilities can be trusted and when additional sensor information is required to maintain resiliency. While previously tested with simulated sensor data, SOM has yet to be tested with real-life sensor data. Furthermore, ARMAS has only been tested with real-life GNSS data. This work expands on …

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A Decision Analysis Framework To Consider Space Congestion In Orbit Selection, Anthony J. Correale Mar 2022

A Decision Analysis Framework To Consider Space Congestion In Orbit Selection, Anthony J. Correale

Theses and Dissertations

Low Earth Orbit (LEO) is becoming more congested, which increases the risk to space missions. Decision makers will need to consider this increase in congestion as an increased risk within their mission engineering process. This thesis proposes a methodology to create and implement a value structure that quantitatively scores a range of orbits based on congestion factors of each orbit and how well each orbit meets mission requirements. This thesis demonstrates this methodology on a set of circular LEO orbits defined by altitude and inclination, and scores this illustrative scenario based on notional mission measures and expected number of encounters …

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Critical Evaluation Of Construction Industry-Related Additive Manufacturing Research: A Scientometric Analysis, Tyler J. Brunjes Mar 2022

Critical Evaluation Of Construction Industry-Related Additive Manufacturing Research: A Scientometric Analysis, Tyler J. Brunjes

Theses and Dissertations

Review of construction-related AM literature is used to identify the advantages, challenges, and current trends of the research. Using a scientometric analysis of 522 bibliographic records, this research systematically analyzed construction related AM research to determine the key research areas and trends. Results showed that starting in 2015, the field has been growing at an exponential rate. Recent AM research focused on materials and reinforcement topics, which matched the most notable challenges of AM, which are material rheology, reinforcement, and lacking construction standards. This study provides an insight into AM research and identifies areas requiring more innovation before its commercial …

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The Impact Of Visual Feedback And Control Configuration On Pilot-Aircraft Interface Using Head Tracking Technology, Christopher M. Arnold Mar 2022

The Impact Of Visual Feedback And Control Configuration On Pilot-Aircraft Interface Using Head Tracking Technology, Christopher M. Arnold

Theses and Dissertations

Traditional control mechanisms restrict human input on the displays in 5th generation aircraft. This research explored methods for enhancing pilot interaction with large, information dense cockpit displays; specifically, the effects of visual feedback and control button configuration when augmenting cursor control with head tracking technology. Previous studies demonstrated that head tracking can be combined with traditional cursor control to decrease selection times but can increase pilot mental and physical workload. A human subject experiment was performed to evaluate two control button configurations and three visual feedback conditions. A Fitts Law analysis was performed to create predictive models of selection time …

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Global Sporadic-E Climatological Analysis Using Gps Radio Occultation And Ionosonde Data, Travis J. Hodos Mar 2022

Global Sporadic-E Climatological Analysis Using Gps Radio Occultation And Ionosonde Data, Travis J. Hodos

Theses and Dissertations

A climatology of sporadic-E (Es) derived from a combined data set of GPS radio occultation (GPS-RO) and ground-based ionosonde soundings is presented for the period from September 2006 to February 2019. The ionosonde soundings were measured using the Lowell Digisonde International (LDI) Global Ionosphere Radio Observatory (GIRO) network consisting of 65 sites and 13,141,060 total soundings. The GPS-RO observations were taken aboard the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites and processed using two binary Es detection algorithms, totaling 9,072,922 occultations. The first algorithm is an S4 amplitude threshold calibrated to the occurrence of any blanketing Es …

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