Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Engineering (3200)
- Physical Sciences and Mathematics (3073)
- Computer Sciences (1280)
- Physics (961)
- Electrical and Computer Engineering (886)
-
- Aerospace Engineering (786)
- Operations Research, Systems Engineering and Industrial Engineering (736)
- Operational Research (420)
- Business (409)
- Optics (349)
- Signal Processing (343)
- Oceanography and Atmospheric Sciences and Meteorology (283)
- Computer Engineering (243)
- Atomic, Molecular and Optical Physics (211)
- Electrical and Electronics (209)
- Environmental Sciences (194)
- Applied Mathematics (189)
- Civil and Environmental Engineering (189)
- Aviation (186)
- Statistics and Probability (183)
- Information Security (181)
- Social and Behavioral Sciences (170)
- Atmospheric Sciences (167)
- Materials Science and Engineering (167)
- Navigation, Guidance, Control and Dynamics (167)
- Plasma and Beam Physics (156)
- Operations and Supply Chain Management (149)
- Electromagnetics and Photonics (142)
- Artificial Intelligence and Robotics (138)
- Engineering Physics (125)
- Keyword
-
- #antcenter (259)
- Machine learning (95)
- #csra (73)
- Algorithms (60)
- Kalman filtering (52)
-
- Computer networks--Security measures (51)
- Image processing (50)
- Neural networks (Computer science) (50)
- Computer security (47)
- Software engineering (47)
- Decision making (45)
- Target acquisition (45)
- Global Positioning System (44)
- Optimization (41)
- Adaptive optics (40)
- Neural networks (40)
- #ctisr (38)
- Remote sensing (36)
- Computer vision (35)
- Drone aircraft (35)
- Synthetic aperture radar (34)
- #afcec (33)
- Artificial intelligence (31)
- Atmospheric turbulence (30)
- Genetic algorithms (29)
- Mathematical optimization (29)
- Flight control (28)
- Object-oriented programming (Computer science) (28)
- Wireless communication systems (28)
- Deep learning (27)
- Publication Year
- Publication
- Publication Type
- File Type
Articles 1471 - 1500 of 5600
Full-Text Articles in Entire DC Network
Assessment Of Structure From Motion For Reconnaissance Augmentation And Bandwidth Usage Reduction, Jonathan B. Roeber
Assessment Of Structure From Motion For Reconnaissance Augmentation And Bandwidth Usage Reduction, Jonathan B. Roeber
Theses and Dissertations
Modern militaries rely upon remote image sensors for real-time intelligence. A typical remote system consists of an unmanned aerial vehicle, or UAV, with an attached camera. A video stream is sent from the UAV, through a bandwidth-constrained satellite connection, to an intelligence processing unit. In this research, an upgrade to this method of collection is proposed. A set of synthetic images of a scene captured by a UAV in a virtual environment is sent to a pipeline of computer vision algorithms, collectively known as Structure from Motion. The output of Structure from Motion, a three-dimensional model, is then assessed in …
Modeling Multimodal Failure Effects Of Complex Systems Using Polyweibull Distribution, Daniel A. Timme
Modeling Multimodal Failure Effects Of Complex Systems Using Polyweibull Distribution, Daniel A. Timme
Theses and Dissertations
The Department of Defense (DoD) enlists multiple complex systems across each of their departments. Between the aging systems going through an overhaul and emerging new systems, quality assurance to complete the mission and secure the nation‘s objectives is an absolute necessity. The U.S. Air Force‘s increased interest in Remotely Piloted Aircraft (RPA) and the Space Warfighting domain are current examples of complex systems that must maintain high reliability and sustainability in order to complete missions moving forward. DoD systems continue to grow in complexity with an increasing number of components and parts in more complex arrangements. Bathtub-shaped hazard functions arise …
Land Cover Influences On Airborne Noise Propagation At Usaf Installations, Ariel L. Waiters
Land Cover Influences On Airborne Noise Propagation At Usaf Installations, Ariel L. Waiters
Theses and Dissertations
Mitigation of aircraft noise and encroachment by residential areas at various U.S. military installations remains a challenge and hampers effective military operations. The Air Force has established standard practices that utilize computational noise models to generate and display noise propagation from military installations. Despite great advances in models and mitigation action plans, the current USAF Noisemap modeling tool and methods do not consider the effects of variation in land cover. Moreover, such limitations could greatly affect the accuracy of predicting aircraft noise pollution. The standard modeling method assumes a ground cover impedance of 225 Kpa*s/m2, which …
Improving Fallout Characterization By Using Multivariate Techniques To Determine Composition, Christopher R. Pitkins
Improving Fallout Characterization By Using Multivariate Techniques To Determine Composition, Christopher R. Pitkins
Theses and Dissertations
Multivariate statistical techniques have been applied in order to un-mix nuclear fallout debris chemical data. This information is critical to characterization of fallout particle formation following a nuclear detonation. Understanding the correlation between environmental precursors and actinide concentrations in post-detonation nuclear fallout material aids in understanding the physical and chemical processes that alter nuclear device signatures in the fireball. This research examines 123 nuclear fallout samples from a historical nuclear test. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) are used to collect chemical compositions of the fallout samples. Principal component analysis (PCA) is applied in order to examine …
Evaluation Of Resiliency In A Wide-Area Backup Protection System Via Model Checking, Kolby H. Elliot
Evaluation Of Resiliency In A Wide-Area Backup Protection System Via Model Checking, Kolby H. Elliot
Theses and Dissertations
Modern civilization relies heavily on having access to reliable power sources. Recent history has shown that present day protection systems are not adequate. Numerous backup protection (BP) systems have been proposed to mitigate the impact of primary protection system failures. Many of these novel BP systems rely on autonomous agents communicating via wide-area networks. These systems are highly complex and their control logic is based on distributed computing. Model checking has been shown to be a powerful tool in analyzing the behavior of distributed systems. In this research the model checker SPIN is used to evaluate the resiliency of an …
Lightning Prediction Using Artificial Neural Networks And Electric Field Mill Data, Daniel E. Hill
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 …
Using An Astrophysical Model To Characterize Nuclear Dust, Anita N. Dunsmore
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 …
Evaluation Of A Cloud Detection Technique Using Spatial And Radiometric Thresholds For Near Infrared Satellite Imagery, William J. Graff
Evaluation Of A Cloud Detection Technique Using Spatial And Radiometric Thresholds For Near Infrared Satellite Imagery, William J. Graff
Theses and Dissertations
Knowledge of cloud location in near infrared (NIR) imagery is of interest to the meteorological community given the wavelengths greater spatial resolution compared to longwave infrared and its potential nighttime applications. This method consists of an algorithm that can be employed by multiple instrument platforms. It analyzes changes between satellite image radiances and a seasonal synthetic background radiance image. The NIR sensor bands of the Sentinel-2 Multispectral Instrument (MSI) and Suomi National Polar-Orbiting Partnership (Suomi NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) satellite instruments are used to evaluate the performance of a monochromatic change detection technique designed to locate areas …
Radiological Decontamination In The Urban Environment Utilizing An Irreversible Wash-Aid Recovery System, Keith A. Sanders
Radiological Decontamination In The Urban Environment Utilizing An Irreversible Wash-Aid Recovery System, Keith A. Sanders
Theses and Dissertations
The radioactive fallout from the Fukushima Daiichi nuclear reactors accident and the ongoing threat of nuclear or radioactive terrorism have forced the need for urban radiological decontamination into the forefront. Many of the established decontamination techniques are not ideally suited for the urban milieu. One of the keys to maximize the effectiveness of long-term remediation and recovery in the urban environment is immediate mitigation within a few days of the incident and before a rain event. The Integrated Wash-Aid, Treatment, and Emergency Reuse System (IWATERS) provides a potentially safe and effective method for early responders and remediation teams to perform …
Analytical Determination Of A Helicopter Height Velocity Diagram, Michael J. Harris
Analytical Determination Of A Helicopter Height Velocity Diagram, Michael J. Harris
Theses and Dissertations
A helicopter height velocity (HV) diagram was analytically constructed using optimal control techniques. A three degree of freedom, point-mass, dynamic model was developed and validated with flight test data. An induced velocity calculation was incorporated which addressed the effects of vortex ring state. The problem was posed as an open final time, constrained initial state, constrained final state problem, with the objective function as a weighted sum of the initial altitude and quadratic controls. This formulation was solved using direct pseudo-spectral collocation and adaptive mesh refinement as implemented by the GPOPS-II® software suite. Proper adjustment of path constraints was crucial …
Defender-Assisted Evasion And Pursuit Maneuvers, Roger S. Anderson
Defender-Assisted Evasion And Pursuit Maneuvers, Roger S. Anderson
Theses and Dissertations
Motivated by the possibilities afforded by active target defense, a 3-agent pursuit-evasion differential game involving an Attacker/Pursuer, a Target/Evader, and a Defender is considered. The Defender strives to assist the Target by intercepting the Attacker before the latter reaches the Target. A barrier surface in a reduced state space separates the winning regions of the Attacker and Target-Defender team. In this thesis, attention focuses primarily on the Attacker's region of win where, under optimal Attacker play, the Defender cannot preclude the Attacker from capturing the Target. Both optimal and suboptimal strategies are investigated. This thesis uses several methods to breakdown …
Assessing And Expanding Extracurricular Cybersecurity Youth Activities' Impact On Career Interest, Michael H. Dunn
Assessing And Expanding Extracurricular Cybersecurity Youth Activities' Impact On Career Interest, Michael H. Dunn
Theses and Dissertations
This thesis assesses and expands the potential of extracurricular activities to address the shortage of cybersecurity workers by increasing secondary school students’ interest in these careers. Competitions and badges, two forms of gamification often applied in extracurricular educational activities, have potential to improve motivation and increase interest in related careers, but are significantly understudied in the context of cybersecurity activities. CyberPatriot is the largest cybersecurity competition in the United States for secondary school students. Impact on participants’ career interests is assessed by analyzing responses to recent surveys conducted by the competition organizers. Analysis demonstrates significantly increased interest in cybersecurity in …
Securing Critical Infrastructure: A Ransomware Study, Blaine M. Jeffries
Securing Critical Infrastructure: A Ransomware Study, Blaine M. Jeffries
Theses and Dissertations
This thesis reviews traditional ransomware attack trends in order to present a taxonomy for ransomware targeting industrial control systems. After reviewing a critical infrastructure ransomware attack methodology, a corresponding response and recovery plan is described. The plan emphasizes security through redundancy, specifically the incorporation of standby programmable logic controllers. This thesis goes on to describe a set of experiments conducted to test the viability of defending against a specialized ransomware attack with a redundant controller network. Results support that specific redundancy schemes are effective in recovering from a successful attack. Further experimentation is conducted to test the feasibility of industrial …
Plasmonic Grating Geometrics And Wavelength-Dependent Focus Depth In Infrared Detectors, Patrick R. Kennedy
Plasmonic Grating Geometrics And Wavelength-Dependent Focus Depth In Infrared Detectors, Patrick R. Kennedy
Theses and Dissertations
The objective for this research is to determine a relationship between plasmonic grating geometries and the wavelength-dependent focus depth. This research is focused on enhancing the signal collected by infrared detectors by using a metal grating as a planar lens to focus light in the detecting region of the substrate. This can be used to maintain a thinner absorbing region and possibly to create multi-color imaging in a single pixel. Simulations demonstrate that the plasmonic lens is capable of creating a wavelength dependent focus spot.
Quality Of Service Impacts Of A Moving Target Defense With Software-Defined Networking, Samuel A. Mayer
Quality Of Service Impacts Of A Moving Target Defense With Software-Defined Networking, Samuel A. Mayer
Theses and Dissertations
An analysis of the impact a defensive network technique implemented with software-defined networking has upon quality of service experienced by legitimate users. The research validates previous work conducted at AFIT to verify claims of defensive efficacy and then tests network protocols in common use (FTP, HTTP, IMAP, POP, RTP, SMTP, and SSH) on a network that uses this technique. Metrics that indicate the performance of the protocols under test are reported with respect to data gathered in a control network. The conclusions of these experiments enable network engineers to determine if this defensive technique is appropriate for the quality of …
Comparison Of Traditional Versus Cubesat Remote Sensing: A Model-Based Systems Engineering Approach, Daniel L. Cipera
Comparison Of Traditional Versus Cubesat Remote Sensing: A Model-Based Systems Engineering Approach, Daniel L. Cipera
Theses and Dissertations
This thesis compares the ability of both traditional and CubeSat remote sensing architectures to fulfill a set of mission requirements for a remote sensing scenario. Mission requirements originating from a hurricane disaster response scenario are developed to derive a set of system requirements. Using a Model-based Systems Engineering approach, these system requirements are used to develop notional traditional and CubeSat architecture models. The technical performance of these architectures is analyzed using Systems Toolkit (STK); the results are compared against Measures of Effectiveness (MOEs) derived from the disaster response scenario. Additionally, systems engineering cost estimates are obtained for each satellite architecture …
Defining Success In Air Force Infrastructure Asset Management Through Use Of The Delphi Method, Brendan J. Maestas
Defining Success In Air Force Infrastructure Asset Management Through Use Of The Delphi Method, Brendan J. Maestas
Theses and Dissertations
Asset Management has a history of policy mandates within the US Government dating back to 1990’s. In order to accomplish these many directives, the Air Force Civil Engineer community has adopted a mindset and framework commonly referred to as Asset Management. Despite numerous references and guidance to establish Asset Management principles, the Air Force has not yet developed a clear and concise way to define or measure overarching success in Asset Management. This research effort focuses on closing the knowledge gap between issued policy and implementation. It examines Asset Management implementation efforts in other government agencies, private industries, and in …
Cost And Performance Difference Of High Performance Sustainable Buildings, Philip A. Ramsey
Cost And Performance Difference Of High Performance Sustainable Buildings, Philip A. Ramsey
Theses and Dissertations
Varying legislation and executive orders coupled with needs for energy resiliency have led the United States Air Force to pursue sustainable construction. The limited understandings of initial costs to implement these changes have contributed to poor project cost estimating and changed implementation of legal requirements. A student t-test for populations with unequal variance was accomplished on the final normalized contract cost of 1628 Air Force Military Construction (MILCON) projects executed between 2002 and 2017. Future design considerations for net zero energy buildings were compiled from a net zero energy residential community in Fontana, California. There was no statistically significant difference …
Air Force Installation Contracting Agency Strategic Sourcing And Category Management Through Expenditure Profiling, James T. Okamoto
Air Force Installation Contracting Agency Strategic Sourcing And Category Management Through Expenditure Profiling, James T. Okamoto
Theses and Dissertations
This thesis examines an approach to characterizing various expenditure profiles for the Air Force Installation Contracting Agency’s Operations and Maintenance Appropriated Funds. Using naive, seasonal naive, trailing moving average, exponential smoothing, linear regression, and autoregressive integrated moving average (ARIMA) forecasting methods, the paper evaluates multiple error measures over one fiscal year to find the most precise model for each level of analysis. Levels of analysis included the Air Force enterprise and level 1 category levels, as well as an illustrative approach to Information and Technology spend at the level 2 subcategory, major command, and base levels. Optimal model characteristics were …
Securing Data In Transit Using Two Channel Communication, Clark L. Wolfe
Securing Data In Transit Using Two Channel Communication, Clark L. Wolfe
Theses and Dissertations
Securing data in transit is critically important to the Department of Defense in todays contested environments. While encryption is often the preferred method to provide security, there exist applications for which encryption is too resource intensive, not cost-effective or simply not available. In this thesis, a two-channel communication system is proposed in which the message being sent can be intelligently and dynamically split over two or more channels to provide a measure of data security either when encryption is not available, or perhaps in addition to encryption. This data spiting technique employs multiple wireless channels operating at the physical layer, …
Expected Coverage (Excov): A Proposal To Compare Fuzz Test Coverage Within An Infinite Input Space, Evan V. Swihart
Expected Coverage (Excov): A Proposal To Compare Fuzz Test Coverage Within An Infinite Input Space, Evan V. Swihart
Theses and Dissertations
A Fuzz test is an approach used to discover vulnerabilities by intentionally sending invalid inputs to a system for the purpose of triggering some type of fault or unintended effect that renders the system vulnerable to an exploit. Fuzz testing is an important cyber-testing technique used to find and fix vulnerabilities before they are exploited. The fuzzing of military data links presents a particular challenge because existing fuzzing tools cannot be easily applied to these systems. As a result, the tools and techniques used to fuzz these links vary widely in sophistication and effectiveness. Because of the infinite, or nearly …
Looking Past The Spark To Find The Fuel Of The Arab Spring Fire, Luke M. Brantley
Looking Past The Spark To Find The Fuel Of The Arab Spring Fire, Luke M. Brantley
Theses and Dissertations
The field of statistical conflict prediction addresses region-wide analysis in eras of stable conflict and peace. This study improves upon those prediction rates in times of volatile conflict and peace seen during the Arab Spring of 2011 to 2015. During this time, higher rates of conflict transition in certain Middle Eastern and North African countries occurred than normally observed in previous studies. Due to the fact that previous prediction models decrease in accuracy during times of volatile conflict transition and since the proper strategy for handling the Arab Spring has been highly debated, this study considers alterations to previous studies …
Improving Personnel Selection Through Value Focused Thinking, Joshua D. Deehr
Improving Personnel Selection Through Value Focused Thinking, Joshua D. Deehr
Theses and Dissertations
Personnel selection has always and will continue to be a challenging endeavor for the military special operations. They want to select the best out of a number of qualified applicants. How an organization determines what makes a successful candidate and how to compare candidates against each other are some of the difficulties that top tier organizations like the special operations face. Value focused thinking (VFT) places criteria in a hierarchal structure and quantifies the values with criteria measurements, known as a decision model. The selection process can be similar to a college selecting their students. This research used college student …
Strategic Sourcing Via Category Management: Helping Air Force Installation Contracting Agency Eat One Piece Of The Elephant, Theodore S. Holliger
Strategic Sourcing Via Category Management: Helping Air Force Installation Contracting Agency Eat One Piece Of The Elephant, Theodore S. Holliger
Theses and Dissertations
The United States Air Force can dramatically reduce resource consumption through strategic sourcing initiatives that leverage sensibly-bound pockets of spend via category management. However, category creation is a particularly daunting task due to the sheer magnitude of purchasing data in large organizations. Text mining is one way to identify categories. Specifically, term frequency analysis, term frequency-inverse document frequency analysis, and topic modeling can identify category membership, unique characteristics of categories, and thematic natures of the categories. This thesis developed an empirical, generalizable, reproducible methodology to analyze historical contract text descriptions to uncover the data’s hidden structure. A sample case was …
Characterization Of Ambient Noise, Rachel C. Ramirez
Characterization Of Ambient Noise, Rachel C. Ramirez
Theses and Dissertations
An Air Force sponsor is interested in improving an acoustic detection model by providing better estimates on how to characterize the background noise of various environments. This would inform decision makers on the probability of acoustic detection of different systems of interest given different levels of noise. Data mining and statistical learning techniques are applied to a National Park Service acoustic summary data set to find overall trends over varying environments. Linear regression, conditional inference trees, and random forest techniques are discussed. Findings indicate only sixteen geospatial variables at different resolutions are necessary to characterize the first ten ⅓ octave …
A Study Of The Hexakis Icosahedron Vacuum Lighter Than Air Vehicle And The Effects Of Air Evacuation On The Structural Integrity, Anthony A. Castello
A Study Of The Hexakis Icosahedron Vacuum Lighter Than Air Vehicle And The Effects Of Air Evacuation On The Structural Integrity, Anthony A. Castello
Theses and Dissertations
The research this paper focuses on is comparing the structural differences between the icosahedron and hexakis icosahedron frame and skin for use as a vacuum lighter than air vehicle (VLTAV), analyzing the stress concentrations in the hexakis icosahedron both with and without the skin, and finding the optimal location and size of the air evacuation method for creating the internal vacuum. Previous research to date has identified dynamic loading on the structure and optimization of the structure, but this will be the first research to analyze the manufacturing of the structure through the development of the air evacuation design. Findings …
2017 Annual Report Of The Graduate School Of Engineering And Management, Air Force Institute Of Technology
2017 Annual Report Of The Graduate School Of Engineering And Management, Air Force Institute Of Technology
AFIT Documents
No abstract provided.
Comparison Of Plume Dynamics For Laser Ablated Metals: Al And Ti, William A. Bauer, Glen P. Perram, Timothy J. Haugan
Comparison Of Plume Dynamics For Laser Ablated Metals: Al And Ti, William A. Bauer, Glen P. Perram, Timothy J. Haugan
Faculty Publications
Emissive plumes from pulsed laser ablation of bulk Ti and Al from KrF laser irradiation at laser fluence up to 3.5 J/cm2 and argon background pressures of 0–1 Torr have been observed using gated intensified charged-coupled device imagery. Mass loss for Ti increases from 0.1 to 0.8 μg/pulse as pulse energy increase from 174 to 282 mJ/pulse (35–170 photons/atom) and decreases by ∼30% as pressure increases from vacuum to 1 Torr. Early plume energies are described by the free expansion velocities of 1.57 ± 0.02 and of 1.81 ± 0.07 cm/μs for Ti and Al, respectively, …
Demonstration Of Versatile Whispering-Gallery Micro-Lasers For Remote Refractive Index Sensing, Lei Wan, Hengky Chandrahalim, Jian Zhou
Demonstration Of Versatile Whispering-Gallery Micro-Lasers For Remote Refractive Index Sensing, Lei Wan, Hengky Chandrahalim, Jian Zhou
Faculty Publications
We developed chip-scale remote refractive index sensors based on Rhodamine 6G (R6G)-doped polymer micro-ring lasers. The chemical, temperature, and mechanical sturdiness of the fused-silica host guaranteed a flexible deployment of dye-doped polymers for refractive index sensing. The introduction of the dye as gain medium demonstrated the feasibility of remote sensing based on the free-space optics measurement setup. Compared to the R6G-doped TZ-001, the lasing behavior of R6G-doped SU-8 polymer micro-ring laser under an aqueous environment had a narrower spectrum linewidth, producing the minimum detectable refractive index change of 4 x 10−4 RIU. The maximum bulk refractive index sensitivity (BRIS) …
Air Force Institute Of Technology Research Report 2017, Graduate School Of Engineering And Management, Air Force Institute Of Technology
Air Force Institute Of Technology Research Report 2017, Graduate School Of Engineering And Management, Air Force Institute Of Technology
AFIT Documents
This Research Report presents the FY18 research statistics and contributions of the Graduate School of Engineering and Management (EN) at AFIT. AFIT research interests and faculty expertise cover a broad spectrum of technical areas related to USAF needs, as reflected by the range of topics addressed in the faculty and student publications listed in this report. In most cases, the research work reported herein is directly sponsored by one or more USAF or DOD agencies. AFIT welcomes the opportunity to conduct research on additional topics of interest to the USAF, DOD, and other federal organizations when adequate manpower and financial …