Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons™

Open Access. Powered by Scholars. Published by Universities.®

Air Force Institute of Technology

Discipline
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 601 - 630 of 3057

Full-Text Articles in Physical Sciences and Mathematics

A Fixed-Point Method For Computing Steady-State 2d Laser-Fluid Interactions, Jeremiah S. Lane Mar 2021

A Fixed-Point Method For Computing Steady-State 2d Laser-Fluid Interactions, Jeremiah S. Lane

Theses and Dissertations

This research introduces a fixed-point numerical approach for solving the steady-state Navier-Stokes (NS) equations on a finite two-dimensional (2D) domain. The steady-state interaction between a high energy laser beam and its surrounding fluid medium is important to researchers in the field of high energy laser beam propagation. The solutions to the steady-state Navier-Stokes equations provide a model for uncovering the steady-state behavior of the fluid medium, which is useful for the modeling of thermal blooming in laser beam propagation. Numerical solutions remain the only tenable option for solving the NS equations, wherein numerical speed and fidelity beget the utility of …

Go to article

Formal Verification For High Assurance Software: A Case Study Using The Spark Auto-Active Verification Toolset, Ryan M. Baity Mar 2021

Formal Verification For High Assurance Software: A Case Study Using The Spark Auto-Active Verification Toolset, Ryan M. Baity

Theses and Dissertations

Software is an increasingly integral and sophisticated part of safety- and mission-critical systems. Poorly written software can lead to information leakage, undetected cyber breaches, and even human injury in cases where the software directly interfaces with components of a physical system. These systems may range from power facilities to remotely piloted aircraft. Software bugs and vulnerabilities can lead to severe economic hardships and loss of life in these domains. As fast as software spreads to automate many facets of our lives, it also grows in complexity. The complexity of software systems combined with the nature of the critical domains dependent …

Go to article

Indoor Navigation Using Convolutional Neural Networks And Floor Plans, Ricky D. Anderson Mar 2021

Indoor Navigation Using Convolutional Neural Networks And Floor Plans, Ricky D. Anderson

Theses and Dissertations

The goal of this thesis is to evaluate a new indoor navigation technique by incorporating floor plans along with monocular camera images into a CNN as a potential means for identifying camera position. Building floor plans are widely available and provide potential information for localizing within the building. This work sets out to determine if a CNN can learn the architectural features of a floor plan and use that information to determine a location. In this work, a simulated indoor data set is created and used to train two CNNs. A classification CNN, which breaks up the floor plan into …

Go to article

Solving The Quantum Layout Problem For Nisq-Era Quantum Computers Via Metaheuristic Algorithms, Brian D. Curran Jr. Mar 2021

Solving The Quantum Layout Problem For Nisq-Era Quantum Computers Via Metaheuristic Algorithms, Brian D. Curran Jr.

Theses and Dissertations

In the noisy intermediate-scale quantum (NISQ)-era, quantum computers (QC) are highly prone to noise-related errors and suffer from limited connectivity between their physical qubits. Circuit transformations must be made to abstract circuits to address the noise and hardware constraints of NISQ-era devices. Such transformations introduce additional gates to the original circuit, thereby reducing the circuit's overall fidelity. To address the aforementioned constraints of NISQ-era QCs, dynamic remapping procedures permute logical qubits about physical qubits of the device to increase the fidelity of operations and make operations hardware-compliant. The quantum layout problem (QLP) is the problem of mapping logical qubits of …

Go to article

Delayed Authentication System For Civilian Satellite, Sean M. Feschak Mar 2021

Delayed Authentication System For Civilian Satellite, Sean M. Feschak

Theses and Dissertations

This thesis presents the feasibility of a Delayed Authentication System (DAS) for civilian satellite navigation (satnav) receivers. In satnav systems, encrypted signal components are transmitted synchronously with civilian components. Hence, the civilian signals can be authenticated by detecting the presence of encrypted signal components within the received signal. To authenticate, a reference station transmits estimated encrypted signal spreading code symbols processed using a high gain antenna. In this thesis, it is shown that a 1-meter diameter dish antenna is adequate to provide a high probability of successful authentication, thereby reducing overall system complexity and cost.

Go to article

Laser Illuminated Imaging: Beam And Scene Deconvolution Algorithm, Benjamin W. Davis Mar 2021

Laser Illuminated Imaging: Beam And Scene Deconvolution Algorithm, Benjamin W. Davis

Theses and Dissertations

Laser illuminated imaging systems deal with several physical challenges that must be overcome to achieve high-resolution images of the target. Noise sources like background noise, photon counting noise, and laser speckle noise will all greatly affect the imaging systems ability to produce a high-resolution image. An even bigger challenge to laser illuminated imaging systems is atmospheric turbulence and the effect that it will have on the imaging system. The illuminating beam will experience tilt, causing the beam to wander off the center of the target during propagation. The light returning to the detector will similarly be affected by turbulence, and …

Go to article

Automated Network Exploitation Utilizing Bayesian Decision Networks, Graeme M. Roberts Mar 2021

Automated Network Exploitation Utilizing Bayesian Decision Networks, Graeme M. Roberts

Theses and Dissertations

Computer Network Exploitation (CNE) is the process of using tactics and techniques to penetrate computer systems and networks in order to achieve desired effects. It is currently a manual process requiring significant experience and time that are in limited supply. This thesis presents the Automated Network Discovery and Exploitation System (ANDES) which demonstrates that it is feasible to automate the CNE process. The uniqueness of ANDES is the use of Bayesian decision networks to represent the CNE domain and subject matter expert knowledge. ANDES conducts multiple execution cycles, which build upon previous action results. Cycles begin by modeling the current …

Go to article

Comparison Of Conic Ray Tracing For Occlusion Determination On 3d Point Cloud Data, Henry Cho Mar 2021

Comparison Of Conic Ray Tracing For Occlusion Determination On 3d Point Cloud Data, Henry Cho

Theses and Dissertations

The US Air Force has been increasing the use of automation in its weapon systems to include the remotely piloted aircraft (RPA) platforms. The RPA career field has had issues with poor pilot retention due to job stressors. For example, RPA operators spend a lot of time and attention surveilling a suspect on the ground for many hours, so adding automation to this activity could help improve pilot retention. The research problem in this thesis attempted to automate the process of observing a ground target. This thesis presents a method termed conic ray tracing for determining visibility and occlusion of …

Go to article

Designing And Building A Radar Simulation Using The Entity Component System, Brennen T. Garland Mar 2021

Designing And Building A Radar Simulation Using The Entity Component System, Brennen T. Garland

Theses and Dissertations

This research explores the implementation of a "medium fidelity" radar simulation using the Entity-Component-System (ECS) architecture. The radar implemented mimics the fundamental characteristics of entities in the open-source Mixed Reality Simulation Platform (MIXR) project, supporting real-time interaction. Previous research has shown the potential benefits of using an ECS-based architecture to support improved execution performance relative to Object-Oriented Programming (OOP) approaches, thus improved real-time interaction requirements. This research implements a well-documented radar model that supports the development of soft real-time human-based interaction simulations. The radar system modeled in this research mimics the "out-of-the-box" fidelity defined in the OOP-based MIXR architecture. This …

Go to article

Optical Study Of 2-D Detonation Wave Stability, Eulaine T. Grodner Mar 2021

Optical Study Of 2-D Detonation Wave Stability, Eulaine T. Grodner

Theses and Dissertations

Fundamental optical detonation study of detonations constricted to a 2-d plane propagation, and detonations propagating around a curve. All images were processed using modern image processing techniques. The optical techniques used were shadowgraph, Schlieren, and chemiluminescence. In the 2-Dstraight channels, it was determined wave stability was a factor of cell size. It was also determined the detonation wave thickness (area between the combustion and shockwave) was a factor of how much heat available for the detonation. For the detonations propagating around a curve, it was determined the three main classifications of wave stability were stable, unstable, and detonation wave restart. …

Go to article

Optimizing A Bank Of Kalman Filters For Navigation Integrity, Luis E. Sepulveda Mar 2021

Optimizing A Bank Of Kalman Filters For Navigation Integrity, Luis E. Sepulveda

Theses and Dissertations

Alternative navigation is an area of research which employs a variety of sensor technologies to provide a navigation solution in Global Navigation Satellite System degraded or denied environments. The Autonomy and Navigation Technology Center at the Air Force Institute of Technology has recently developed the Autonomous and Resilient Management of All-source Sensors (ARMAS) navigation framework which utilizes an array of Kalman Filters to provide a navigation solution resilient to sensor failures. The Kalman Filter array size increases exponentially as system sensors and detectable faults are scaled up, which in turn increases the computational power required to run ARMAS in areal-world …

Go to article

Exploring Fog Of War Concepts In Wargame Scenarios, Dillon N. Tryhorn Mar 2021

Exploring Fog Of War Concepts In Wargame Scenarios, Dillon N. Tryhorn

Theses and Dissertations

This thesis explores fog of war concepts through three submitted journal articles. The Department of Defense and U.S. Air Force are attempting to analyze war scenarios to aid the decision-making process; fog modeling improves realism in these wargame scenarios. The first article "Navigating an Enemy Contested Area with a Parallel Search Algorithm" [1] investigates a parallel algorithm's speedup, compared to the sequential implementation, with varying map configurations in a tile-based wargame. The parallel speedup tends to exceed 50 but in certain situations. The sequential algorithm outperforms it depending on the configuration of enemy location and amount on the map. The …

Go to article

Improving Text Classification With Semantic Information, Joshua H. White Mar 2021

Improving Text Classification With Semantic Information, Joshua H. White

Theses and Dissertations

The Air Force contracts a variety of positions, from Information Technology to maintenance services. There is currently no automated way to verify that quotes for services are reasonably priced. Small training data sets and word sense ambiguity are challenges that such a tool would encounter, and additional semantic information could help. This thesis hypothesizes that leveraging a semantic network could improve text-based classification. This thesis uses information from ConceptNet to augment a Naive Bayes Classifier. The leveraged semantic information would add relevant words from the category domain to the model that did not appear in the training data. The experiment …

Go to article

Identifying Four Year Average Cloud Field Regimes From World Wide Merged Cloud Analysis Dataset By Way Of K-Means Clustering, Stewart G. Almeida Mar 2021

Identifying Four Year Average Cloud Field Regimes From World Wide Merged Cloud Analysis Dataset By Way Of K-Means Clustering, Stewart G. Almeida

Theses and Dissertations

Joint histograms of cloud top height (CTH) and optical depth (OD) are created using the World-Wide Merged Cloud Analysis (WWMCA) dataset over a four year period (2014-2017) to identify average cloud field regimes and assess the application of utilizing the WWMCA dataset with the AFIT Sensor and Scene Emulation Tool (ASSET). Two selected regions encompassing the Florida peninsula and a portion of the Pacific Ocean off the west-central coast of South America are examined over the months of January and July. Cloud field regimes are identified by running generated hourly OD-CTH histograms through k-means clustering, with optimal cluster number ( …

Go to article

A Comparative Evaluation Of The Fast Optical Pulse Response Of Event-Based Cameras, Tyler J. Brewer Mar 2021

A Comparative Evaluation Of The Fast Optical Pulse Response Of Event-Based Cameras, Tyler J. Brewer

Theses and Dissertations

Event cameras use biologically inspired readout circuit architecture to offer a faster and more efficient method of imaging than traditional frame-based detectors. The asynchronous event reporting circuit timestamps events to 1 microsecond resolution, but latency increases when many pixels are stimulated simultaneously. To characterize this variability, the DAVIS240, DAVIS346, DVXPlorer, and Prophesee Gen3M VGA-CD 1.1 cameras were exposed to single step-function flashes with amplitudes from 9.3-771cd/m2, stimulating from 0.0042-100 of pixels. The Median Absolute Deviation of pixel response times ranged between 0 and 6086µs, increasing with the percent of pixels stimulated (PSP). The number of events generated per …

Go to article

Neuromorphic Vision Sensors For Space-Based Applications, Jessica L. Horn Mar 2021

Neuromorphic Vision Sensors For Space-Based Applications, Jessica L. Horn

Theses and Dissertations

This research examines the viability of event-based vision (neuromorphic) sensors for future use on satellites. Outputting single pixel events only when a change in intensity is detected, event-based vision sensors offer a potential low power, low latency, high temporal resolution, and high dynamic range solution as compared to traditional CCD or CMOS camera technology. The commercial off-the-shelf DVS240C sensor, is analyzed to determine if operability is affected by launch conditions and the low Earth space environment through vacuum, thermal vacuum, and vibration tests. No appreciable changes in sensor operation was observed throughout testing. Additionally, the sensor was able to detect …

Go to article

Accurate Covariance Estimation For Pose Data From Iterative Closest Point Algorithm, Rick H. Yuan Mar 2021

Accurate Covariance Estimation For Pose Data From Iterative Closest Point Algorithm, Rick H. Yuan

Theses and Dissertations

One of the fundamental problems of robotics and navigation is the estimation of relative pose of an external object with respect to the observer. A common method for computing the relative pose is the Iterative Closest Point (ICP) algorithm, where a reference point cloud of a known object is registered against a sensed point cloud to determine relative pose. To use this computed pose information in down-stream processing algorithms, it is necessary to estimate the uncertainty of the ICP output, typically represented as a covariance matrix. In this thesis a novel method for estimating uncertainty from sensed data is introduced. …

Go to article

Comparison Of Spatial Precipitation Forecasts With A Satellite Dataset, Andrew C. Siebels Mar 2021

Comparison Of Spatial Precipitation Forecasts With A Satellite Dataset, Andrew C. Siebels

Theses and Dissertations

The purpose of this research is to analyze and compare global precipitation data from the Climate Forecast System Version 2 (CFSv2) with the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN)-Climate Data Record (CDR) to improve long term precipitation forecasting. The CFSv2 has a 0.5-degree resolution which will provide model data for precipitation forecasts. The PERSIANN-CDR is a satellite derived daily 0.25-degree dataset with 37 years of global precipitation coverage 60 N to 60 S. The 0-to-10, 15-to-25, 55-to-65, and 80-to-90 day forecast time frames will then be analyzed for accuracy, and a quantile mapping (QM) technique …

Go to article

Nonlinear Solution Of The Time Eigenvalue Of A Fast Burst Reactor Using The Finite Volume Method, Stephen H. Baxter Mar 2021

Nonlinear Solution Of The Time Eigenvalue Of A Fast Burst Reactor Using The Finite Volume Method, Stephen H. Baxter

Theses and Dissertations

This effort models fast burst reactors using the one dimensional, one group neutron diffusion equation to solve for the time eigenvalue, a method for which an analytical solution exists against which the numerical results can be verified. An existing solution method is enhanced by the addition of a second order accurate finite volume discretization, which is then used to model two separate fast burst reactors. The results of these models are then compared to the results of previous work, the analytical solution, and existing experimental burst width data for each of the two reactors.

Go to article

The Effect Of Amino Acids And Molar Peroxide Ratio On The Oxidation Of 2,4 Dinitroanisole In An Ultraviolet Light Emitting Diode/H2O2 Advanced Oxidation Process, Jeffry P. Hart Mar 2021

The Effect Of Amino Acids And Molar Peroxide Ratio On The Oxidation Of 2,4 Dinitroanisole In An Ultraviolet Light Emitting Diode/H2O2 Advanced Oxidation Process, Jeffry P. Hart

Theses and Dissertations

2,4 Dinitroanisole (DNAN) is an organic insensitive munition that is a likely candidate to replace trinitrotoluene (TNT) for a variety of purposes. Advanced Oxidation Processes (AOPs) are a promising method that have the potential to reduce a variety of persistent chemicals, however, the performance of these systems may be degraded by co-contaminants in the influent. In this contribution, DNAN, with casamino acids as a co-contaminant, was oxidized with Ultraviolet (UV) Light Emitting Diodes (LEDs) with hydrogen peroxide (H2O2) in an AOP in a laboratory. The UV/ H2O2 AOP was capable of degrading DNAN …

Go to article

Crop Circles In The Corn Belt: A Farm-Scale Model To Curb Future Crop Yield Loss With Blended Policy-Structural Adaptations, Daniel Ress Mar 2021

Crop Circles In The Corn Belt: A Farm-Scale Model To Curb Future Crop Yield Loss With Blended Policy-Structural Adaptations, Daniel Ress

Theses and Dissertations

In today's rainfed agricultural regions farmers reliably produce marketable yields without the need for irrigation technology or specific planting policies. However, climate change is expected to challenge global food security. As a result, farmers might seek adaptation strategies. This research investigates the spatiotemporal suitability of blended policy-structural adaptations to reduce yield losses in Greene County, Ohio. A crop-water model is used to calibrate and generate field-scale yield predictions. The resultant framework holds the potential to inform farmer and county-level decision making under future climate uncertainty, and it illustrates the tradeoffs between adaptation cost and yield security.

Go to article

Unsupervised Clustering Of Rf-Fingerprinting Features Derived From Deep Learning Based Recognition Models, Christian T. Potts Mar 2021

Unsupervised Clustering Of Rf-Fingerprinting Features Derived From Deep Learning Based Recognition Models, Christian T. Potts

Theses and Dissertations

RF-Fingerprinting is focus of machine learning research which aims to characterize wireless communication devices based on their physical hardware characteristics. It is a promising avenue for improving wireless communication security in the PHY layer. The bulk of research presented to date in this field is focused on the development of features and classifiers using both traditional supervised machine learning models as well as deep learning. This research aims to expand on existing RF-Fingerprinting work by approaching the problem through the lens of an unsupervised clustering problem. To that end this research proposes a deep learning model and training methodology to …

Go to article

Impendance Probe Payload Development For Space-Based Joint Service Collaboration, Brian T. Kay Mar 2021

Impendance Probe Payload Development For Space-Based Joint Service Collaboration, Brian T. Kay

Theses and Dissertations

Collaborations utilizing small spacecraft in near earth orbit between the U. S. Coast Guard Academy (CGA), Naval Research Lab (NRL), the U. S. Naval Academy (USNA), and the Air Force Institute of Technology (AFIT) have initiated scientific and engineering space-based experiments. Sourced opportunities like the VaSpace ThinSat missions have provided a platform for payload, sensor, and experiment development that would have otherwise been resource prohibitive. We have constructed an impedance probe payload derived from the existing ‘Space PlasmA Diagnostic suitE’ (SPADE) mission operating from NASA’s International Space Station. Currently both space and laboratory plasmas are investigated with AC impedance measurements …

Go to article

Optimizing Critical Values And Combining Axes For Multi-Axial Neck Injury Criteria, Ethan J. Gaston Mar 2021

Optimizing Critical Values And Combining Axes For Multi-Axial Neck Injury Criteria, Ethan J. Gaston

Theses and Dissertations

The Air Force employs ejection seats in its high-performance aircraft. While these systems are intended to ensure aircrew safety, the ejection process subjects the aircrew to potentially injurious forces. System validation includes evaluation of forces against a standard which is linked to the probability of injury. The Muti-Axial Neck Injury Criteria (MANIC) was developed to account for forces in all six degrees of freedom. Unfortunately, the MANIC is applied to each of the three linear input directions separately and applies different criterion values for each direction. These three separate criteria create a lack of clarity regarding acceptable neck loading, leading …

Go to article

Enhanced Space Object Detection Without Prior Knowledge Of The Point Spread Function, Grant F. Graupmann Mar 2021

Enhanced Space Object Detection Without Prior Knowledge Of The Point Spread Function, Grant F. Graupmann

Theses and Dissertations

Since the point detector was created, other detection algorithms have been created that increase the probability of detection, while still keeping the same probability of false alarm. The point detector still has uses, such as when there is no prior knowledge of the point spread function (PSF). The matched filter correlator (MFC) detector is reliant on prior knowledge of the PSF. This has been an issue in cases where the PSF information is potentially inaccurate or unknown. This thesis utilizes MFC detector in a manner that it has never been used before, along with a new detection algorithm, the Pearson's …

Go to article

A Cyber Threat Taxonomy And A Viability Analysis For False Injections In The Tcas, John W. Hannah Mar 2021

A Cyber Threat Taxonomy And A Viability Analysis For False Injections In The Tcas, John W. Hannah

Theses and Dissertations

This thesis provided background information on the Traffic Collision Avoidance System (TCAS). Additionally, the thesis developed a threat taxonomy for TCAS, resulting in the determination that a false injection attack presents the most comprehensive risk. Moreover, the thesis presents the development of a program to determine what ranges, altitudes, and relative bearings are most vulnerable to a false injection attack. The program includes test for all requirements of a successful false injection. Furthermore, the thesis presents an analysis of results and creates threat maps as situational awareness tools. Lastly, the thesis discusses potential solutions to the false injection attack, covers …

Go to article

Performance Of Various Low-Level Decoder For Surface Codes In The Presence Of Measurement Error, Claire E. Badger Mar 2021

Performance Of Various Low-Level Decoder For Surface Codes In The Presence Of Measurement Error, Claire E. Badger

Theses and Dissertations

Quantum error correction is a research specialty within the area of quantum computing that constructs quantum circuits that correct for errors. Decoding is the process of using measurements from an error correcting code, known as error syndrome, to decide corrective operations to perform on the circuit. High-level decoding is the process of using the error syndrome to perform corrective logical operations, while low-level decoding uses the error syndrome to correct individual data qubits. Research on machine learning-based decoders is increasingly popular, but has not been thoroughly researched for low-level decoders. The type of error correcting code used is called surface …

Go to article

Comparison Of Machine Learning Techniques On Trust Detection Using Eeg, James R. Elkins Mar 2021

Comparison Of Machine Learning Techniques On Trust Detection Using Eeg, James R. Elkins

Theses and Dissertations

Trust is a pillar of society and is a fundamental aspect in every relationship. With the use of automated agents in todays workforce exponentially growing, being able to actively monitor an individuals trust level that is working with the automation is becoming increasingly more important. Humans often have miscalibrated trust in automation and therefore are prone to making costly mistakes. Since deciding to trust or distrust has been shown to correlate with specific brain activity, it is thought that there are EEG signals which are associated with this decision. Using both a human-human trust and a human-machine trust EEG dataset …

Go to article

Infiniband Network Monitoring: Challenges And Possibilities, Kyle D. Hintze Mar 2021

Infiniband Network Monitoring: Challenges And Possibilities, Kyle D. Hintze

Theses and Dissertations

Within the realm of High Performance Computing, the InfiniBand Architecture is among the leading interconnects used today. Capable of providing high bandwidth and low latency, InfiniBand is finding applications outside the High Performance Computing domain. One of these is critical infrastructure, encompassing almost all essential sectors as the work force becomes more connected. InfiniBand is not immune to security risks, as prior research has shown that common traffic analyzing tools cannot effectively monitor InfiniBand traffic transmitted between hosts, due to the kernel bypass nature of the IBA in conjunction with Remote Direct Memory Access operations. If Remote Direct Memory Access …

Go to article

Low-Cost Terrestrial Demonstration Of Autonomous Satellite Proximity Operations, Zackary R. Hewitt Mar 2021

Low-Cost Terrestrial Demonstration Of Autonomous Satellite Proximity Operations, Zackary R. Hewitt

Theses and Dissertations

The lack of satellite servicing capabilities significantly impacts the development and operation of current orbital assets. With autonomous solutions under consideration for servicing, the purpose of this research is to build and validate a low-cost hardware platform to expedite the development of autonomous satellite proximity operations. This research aims to bridge the gap between simulation and existing higher fidelity hardware testing with an affordable alternative. An omnidirectional variant of the commercially available TurtleBot3 mobile robot is presented as a 3-DOF testbed that demonstrates a satellite servicing inspection scenario. Reference trajectories for the scenario are generated via optimal control using the …

Go to article

First Prev Next Last