Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Aerospace Engineering (1664)
- Electrical and Computer Engineering (1332)
- Operations Research, Systems Engineering and Industrial Engineering (1238)
- Physical Sciences and Mathematics (1164)
- Operational Research (605)
-
- Signal Processing (455)
- Computer Sciences (443)
- Civil and Environmental Engineering (421)
- Computer Engineering (414)
- Aviation (353)
- Electrical and Electronics (350)
- Physics (350)
- Materials Science and Engineering (329)
- Business (297)
- Navigation, Guidance, Control and Dynamics (250)
- Other Operations Research, Systems Engineering and Industrial Engineering (232)
- Systems Engineering (228)
- Electromagnetics and Photonics (190)
- Aerodynamics and Fluid Mechanics (188)
- Environmental Engineering (185)
- Engineering Science and Materials (176)
- Nuclear Engineering (176)
- Mechanical Engineering (169)
- Digital Communications and Networking (166)
- Space Vehicles (159)
- Optics (147)
- Management and Operations (144)
- Operations and Supply Chain Management (135)
- Semiconductor and Optical Materials (126)
- Keyword
-
- #antcenter (324)
- #csra (125)
- Global Positioning System (63)
- Image processing (61)
- #afcec (60)
-
- Optimization (54)
- Additive manufacturing (51)
- Decision making (51)
- Kalman filtering (51)
- Flight control (48)
- Machine learning (48)
- Target acquisition (47)
- Drone aircraft (46)
- Algorithms (45)
- Microelectromechanical systems (44)
- Composite materials (41)
- Artificial satellites (38)
- Synthetic aperture radar (38)
- Computer vision (37)
- Neural networks (Computer science) (37)
- Computer networks--Security measures (35)
- Signal processing (35)
- Finite element method (33)
- Scheduling (32)
- Simulation (31)
- Decision support systems (30)
- Neural networks (30)
- Remote sensing (28)
- Wireless communication systems (28)
- Silicon carbide (26)
- Publication Year
- Publication
- Publication Type
- File Type
Articles 871 - 900 of 5699
Full-Text Articles in Engineering
Application Of Artificial Neural Networks To Elemental Assay Data For Nuclear Forensics Analysis, Jason G. Seik
Application Of Artificial Neural Networks To Elemental Assay Data For Nuclear Forensics Analysis, Jason G. Seik
Theses and Dissertations
There is a need to quickly and accurately determine the likely physical origins of a collected sample for nuclear treaty verification purposes. The objective of this research is to prove there is a means to relate different samples (Q-values) to one another using a 'same versus not-same' artificial neural network called a Siamese network. This would provide the capability of comparing an unknown sample to a database of samples with known physical origins. Using moment transformations on current data has shown to increase the prediction capabilities of a Siamese network, and using a triplet loss function in connection with the …
Improving Airfield Pavement Degradation Prediction Skill With Local Climate And Traffic, Evan M. Fortney
Improving Airfield Pavement Degradation Prediction Skill With Local Climate And Traffic, Evan M. Fortney
Theses and Dissertations
Airfield pavements are a critical component of the global transportation network that provide a platform for national defense. Preventative and corrective maintenance activities are founded upon accurate expectations of degradation. The leading pavement management software creates degradation predictions from pavement groups using age as the IV and current state conditions as the DV. For this work, a framework is created and implemented that utilizes a PCR model to build upon accepted practices for degradation modeling to enhance and possibly augment future prediction capabilities. The model was applied to pairs of location and pavement family and reveals several findings: the selected …
Surface Defect Detection In Aircraft Skin & Visual Navigation Based On Forced Feature Selection Through Segmentation, Tyler B. Hussey
Surface Defect Detection In Aircraft Skin & Visual Navigation Based On Forced Feature Selection Through Segmentation, Tyler B. Hussey
Theses and Dissertations
Visual inspection of aircraft skin for surface defects is an area of maintenance that is particularly intensive for time and manpower. One novel way to combat this problem is through the use of computer vision and the advent of Artificial Neural Networks (ANN), or more specifically, semantic segmentation via Convolutional Neural Networks (CNN). The research in the paper explores the use of semantic segmentation of aerial imagery as a way to force feature selection onto key areas of an image that might be more likely to correspond under seasonal variations. Utilizing feature selection and matching on the masked aerial image …
Examining The Impact Of Logistics On Military Strength Among European Nations Using Data Envelopment Analysis, Hunter C. Kalin
Examining The Impact Of Logistics On Military Strength Among European Nations Using Data Envelopment Analysis, Hunter C. Kalin
Theses and Dissertations
The purpose of this study is to evaluate if logistics and economic factors affect how a country achieves its military power. Countries have focused on material factors such as nuclear weapons or massive military presence for far too long. What has not been discussed is, do other factors play a role in achieving military power. This study applied Data Envelopment Analysis (DEA) and linear regression to a series of United States European Command (EUCOM) countries and the United States to understand how efficient each country was at achieving its military power. Additionally, the overall relationship between military power and each …
Accelerating Point Set Registration For Automated Aerial Refueling, Ryan M. Raettig
Accelerating Point Set Registration For Automated Aerial Refueling, Ryan M. Raettig
Theses and Dissertations
The goal of AAR is to control the tanker boom to safely refuel a receiving aircraft with no input or aid from the boom operator. To achieve this, the pose of the receiver relative to the tanker must be known. Point set registration is a fundamental issue used to estimate the relative pose of an object in an environment. However, it's likely a computational bottleneck of a vision processing pipeline. In addition, the matching of each sensed point with a closest truth point, nearest neighbor matching, is the most costly portion of the point set registration process. For this reason, …
Indoor Navigation Using Convolutional Neural Networks And Floor Plans, Ricky D. Anderson
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 …
Mitigating The Multipath Effects On Radio Tomographic Imaging, Destinee N. Battle
Mitigating The Multipath Effects On Radio Tomographic Imaging, Destinee N. Battle
Theses and Dissertations
Various radio tomographic imaging (RTI) models and reconstruction methods are equipped with capabilities to mitigate the effects of multipath interference. This thesis combined the network shadowing (NeSh) and weighting-g models in conjunction with Tikhonov regularization and low-rank and sparse decomposition (LRSD). MATLAB was used to implement the four combinations for six experimental data sets and produce attenuation images. The attenuation images were analyzed qualitatively and quantitatively to accomplish the goal of determining which combination performed best at locating human targets. After analyzing the results, it was determined that no single combination outperformed the others for at least three out of …
Delayed Authentication System For Civilian Satellite, Sean M. Feschak
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.
Laser Illuminated Imaging: Beam And Scene Deconvolution Algorithm, Benjamin W. Davis
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 …
Automated Network Exploitation Utilizing Bayesian Decision Networks, Graeme M. Roberts
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 …
Comparison Of Conic Ray Tracing For Occlusion Determination On 3d Point Cloud Data, Henry Cho
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 …
Modeling Aircraft Disturbance Fields For Magnetic Navigation Using Dense Anns And The Novel Manntl Architecture, Kyle A. Emery
Modeling Aircraft Disturbance Fields For Magnetic Navigation Using Dense Anns And The Novel Manntl Architecture, Kyle A. Emery
Theses and Dissertations
The ability to use GPS for navigation is becoming increasingly limited in certain areas of the world. Knowing this, the Air Force Research Labs is constantly looking for ways to improve alternate navigation methods such as magnetic navigation. In the interest of making advancements in aircraft disturbance field modelling, Lieutenant Emery recreates models from previous works to prove results. Lieutenant Emery also introduces a novel model architecture that attempts to mix the filtering properties of Tolles-Lawson with the non-linear capabilities of an artificial neural network. The introduction of this model could present better aircraft disturbance field modelling and in turn, …
Optical Study Of 2-D Detonation Wave Stability, Eulaine T. Grodner
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. …
Strategic Upgrade Scheduling And Portfolio Management To Fortify Contested Networks, Justin L. Anderson
Strategic Upgrade Scheduling And Portfolio Management To Fortify Contested Networks, Justin L. Anderson
Theses and Dissertations
The nuclear command, control, and communication (NC3) network provides an effective deterrent against adversaries by maintaining robust communication between assets, operators, and decision makers. NC3 must receive a series of upgrades to remain an effective deterrent against evolving threats around the globe. Given a contested network and a portfolio of network upgrades, this research seeks an optimal upgrade schedule to maximize network resilience in support of NC3 modernization. Our research contributes a model that solves a budget-constrained network upgrade scheduling problem (NUSP). The NUSP is a defender-attacker-defender tri-level optimization model that achieves fortification via selecting and scheduling network upgrades. The …
Reducing Military Personnel Flight Wait Times Using A Simulation, Matthew D. Cornman
Reducing Military Personnel Flight Wait Times Using A Simulation, Matthew D. Cornman
Theses and Dissertations
A shortage of resources and system failures have put a strain on Military Personnel Flights (MPFs) being able to service their customers in a timely manner. Prolonged customer wait times are becoming a common problem in most MPFs creating problems between the relationship of the customers and leadership. This research uses historical data of an MPF to develop a simulation model of daily operations in an MPF. Subject matter expertise of current MPF operations and resource levels were used to provide a baseline model of the MPF queuing system. The analysis examines the effects of number of Defense Enrollment Eligibility …
Optimizing A Bank Of Kalman Filters For Navigation Integrity, Luis E. Sepulveda
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 …
Exploring Fog Of War Concepts In Wargame Scenarios, Dillon N. Tryhorn
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 …
Utilizing Software Defined Radios For Increased Bandwidth In Satellite Communications, Brian M. Wright
Utilizing Software Defined Radios For Increased Bandwidth In Satellite Communications, Brian M. Wright
Theses and Dissertations
This research explores the background and future possibilities of using cooperative satellites equipped with Software Defined Radios (SDRs) to combine their bandwidth and increase their signal reliability. Software Defined Radios are a potential solution to realize various software applications that support a reconfigurable and adaptive communication system without altering any hardware devices or features. This benefit, along with others that are offered by SDRs and the ongoing improvements in commercial digital electronics have sparked an interest in developing small satellites for advanced communications. This research effort sets out to prove if a high bandwidth signal can be generated by using …
Improving Air Battle Management Target Assignment Processes Via Approximate Dynamic Programming, Joseph M. Liles Iv
Improving Air Battle Management Target Assignment Processes Via Approximate Dynamic Programming, Joseph M. Liles Iv
Theses and Dissertations
Military air battle managers face many challenges when directing operations in quickly evolving combat scenarios. These scenarios require rapid decisions to engage moving and unpredictable targets. In defensive operations, the success of a sequence of air battle management decisions is reflected by the friendly force's ability to maintain air superiority by defending friendly assets. We develop a Markov decision process (MDP) model of the air battle management (ABM)problem, wherein a set of unmanned combat aerial vehicles (UCAV) is tasked to defend a central asset from cruise missiles that arrive stochastically over time.
The Impact Of Triage Classification Errors On Military Medical Evacuation System Performance, Emily S. Graves
The Impact Of Triage Classification Errors On Military Medical Evacuation System Performance, Emily S. Graves
Theses and Dissertations
In a deployed environment, evacuation requests of injured personnel are serviced by multiple forms of evacuation including medical evacuation (MEDEVAC) and casualty evacuation (CASEVAC). This thesis focuses on the optimal dispatching policy for MEDEVAC units when triage classification errors and blood transfusion kits are considered. A discounted, infinite-horizon Markov decision process (MDP) model is formulated to analyze the MEDEVAC dispatching problem and determine the optimal policy based on the status of the MEDEVAC units in the system, the priority level of incoming requests, and the locations from which requests originate. A notional, representational scenario based in Azerbaijan is utilized to …
Resupply Operations Of A Dispersed Infantry Brigade Combat Team Using Approximate Dynamic Programming, Camero K. Song
Resupply Operations Of A Dispersed Infantry Brigade Combat Team Using Approximate Dynamic Programming, Camero K. Song
Theses and Dissertations
Military sustainment planners must consider the effective employment of Cargo Unmanned Aerial Vehicles (CUAVs) into resupply operations under austere threat conditions. Viewed as an inventory routing problem, the complexities of resupplying dislocated Forward Operating Bases (FOBs) under dangerous and dynamic conditions warrant additional features to the baseline problem. This research models a military stochastic inventory routing problem with multiple routing (MIL SIRP- MR) as a Markov decision process (MDP) model and provides high-quality policy solutions using a combination of approximate dynamic programming and ordinal optimization techniques.
Neuromorphic Vision Sensors For Space-Based Applications, Jessica L. Horn
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 …
Allocation Of Scarce Healthcare Resources In A Military Treatment Facility During A Pandemic: A Comparison Of Goal Programming And Portfolio Decision Analysis Methods, Donald B. Hale
Theses and Dissertations
In a pandemic, healthcare decisionmakers face the challenge of allocating critical, but scarce healthcare resources in a dynamic, uncertain environment. Their decisions will not only affect the patients coming to the hospital for treatment, but also the Military Treatment Facility's personnel responsible. The decisionmaker must decide how to allocate these resources to achieve multiple, conflicting objectives under multiple constraints. In response, we propose a methodology for the implementation of both Portfolio Decision Analysis and Goal Programming. The steps of this methodology provide a framework with which the decisionmaker can develop optimal allocation of resources. This framework was then applied to …
Automated Sentiment Analysis For Personnel Survey Data In The Us Air Force Context, Julia M. Haines
Automated Sentiment Analysis For Personnel Survey Data In The Us Air Force Context, Julia M. Haines
Theses and Dissertations
When surveys are distributed across the Air Force (AF), whether it be an employee engagement survey, a climate survey, or similar, significant resources are put towards the development, distribution and analysis of the survey. However, when open ended questions are included on these surveys, respondent comments are generally underutilized, more often treated as a source for pull-quotes rather than a data source in and of themselves. This is due to a lack of transparency and confidence in the accuracy of machine-aided methods such as sentiment analysis and topic modeling. This confidence reduces further when the text has special context, such …
An Examination Of Potential Training Regression Recognition Algorithms For Pilot Training Next, Alex R. Gaines
An Examination Of Potential Training Regression Recognition Algorithms For Pilot Training Next, Alex R. Gaines
Theses and Dissertations
The initiative to reduce the Air Forces serious pilot shortage lead to the Pilot Training Next (PTN) program. Under PTN, student pilots progress at an individual rate while making increased use of simulator-based training resources. A previous thesis used data from the first PTN class to conceptualize and prototype a student training flight scheduler. This scheduler did not consider training events required to bring students back to achieved levels of performance if in fact that student performance had regressed. This thesis examines three classes of PTN student data to determine whether student regression in training progression can be detected. A …
Improving Manufacturability And Reducing Cracking In Additively Manufactured Tungsten Alloys, Christopher P. Fassio
Improving Manufacturability And Reducing Cracking In Additively Manufactured Tungsten Alloys, Christopher P. Fassio
Theses and Dissertations
Additively Manufactured tungsten suffers from low () densities due to high concentrations of microcracks as the printed layers cool past tungsten's high ductile to brittle transition temperature. In this study, tungsten-rhenium and tungsten rhenium hafnium carbide compositions were evaluated on density and tensile strength. In addition to varying the compositions of each alloy, printing parameters and post-processing methods were also compared. Print parameters varied for all compositions on an MLab 200R C using included the laser scan strategy, hatch spacing, scan speed, laser power, and print bed material. Post processing techniques of the WRe compositions included hot isostatic pressing and …
Impendance Probe Payload Development For Space-Based Joint Service Collaboration, Brian T. Kay
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 …
Optimizing Critical Values And Combining Axes For Multi-Axial Neck Injury Criteria, Ethan J. Gaston
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 …
An Empirical Analysis Of Dod Construction Task Order Performance, Adam B. Teston, Tyler S. Stout
An Empirical Analysis Of Dod Construction Task Order Performance, Adam B. Teston, Tyler S. Stout
Theses and Dissertations
Cost and schedule overrun plague over 50 of all construction projects, engendering diminished available funding that leads to deferred maintenance and impaired award ability for needed projects. Though existing research attempts to identify overruns sources, the results are inconclusive and frequently differ. Accordingly, this research reviews DoD construction contract data from the past ten years to identify the contract attributes of 79,894 projects that correlate with superior performance for use in future project execution. This research starts with creating a database that houses the largest single source of construction contract information. The research then evaluates the data to determine if …
Supporting Space Domain Awareness Through The Development And Analysis Of Space Object Detection Algorithms Employed By Ground-Based Telescopes, Connor A. Paw
Theses and Dissertations
Detection algorithms are instrumental in maintaining space domain awareness, specifically in the observation, monitoring, and categorization of unknown space objects. State of the art detection algorithms utilize a matched filter or a spatial correlator on long exposure image data to make pixel-wise detection decisions. This thesis investigates the advantages and practical potential of two different post-processing detection algorithms that can be employed by ground-based telescopes. The first algorithm explored is based on a long exposure Fourier domain processing technique, while the second is centered around frame selection from a series of short exposure images. The results of the experiments performed …