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 1891 - 1920 of 5600
Full-Text Articles in Entire DC Network
Photon Sieve Bandwidth Broadening By Reduction Of Chromatic Aberration Effects Using Second-Stage Diffractive Optics, Christopher M. Tulip
Photon Sieve Bandwidth Broadening By Reduction Of Chromatic Aberration Effects Using Second-Stage Diffractive Optics, Christopher M. Tulip
Theses and Dissertations
A photon sieve is a lightweight diffractive optic which can be useful for space-based imaging applications. It is limited by chromatic aberration and a narrow bandwidth. A Fresnel zone plate is used to counteract this effect in a manner similar to that accomplished with a traditional holographic corrector. First, a radiometric analysis established a target for bandwidth improvement. Next, a sieve was designed, fabricated, and characterized. Third, the bandwidth-broadening correction scheme was developed to correct primary chromatic aberration. Finally, a zone plate was designed, fabricated, and tested. Performance of the corrected system was measured over the target bandwidth. The corrected …
Non-Destructive Techniques For Classifying Aircraft Coating Degradation, Kody A. Wilson
Non-Destructive Techniques For Classifying Aircraft Coating Degradation, Kody A. Wilson
Theses and Dissertations
In this research non-destructive techniques were examined as possible methods of determining aircraft coating degradation. Single Value Decomposition(SVD)-Linear Discriminant Analysis(LDA) algorithms were applied to measured spectra. When applied to infrared emittance spectra only 52% classification accuracy was achieved. When applied to Raman spectroscopy a higher classification accuracy of 70.4% is attained when using the same SVD-LDA algorithm. However the best performing measurement was using infrared reflectance classification accuracies were 100%, 99.83% and 94.4% when using the Bomem FTS, DRIFTS and Telops respectively for one of the sample sets. For DRIFTS data a more accurate fingerprint region was identified 865.6 - …
Autonomous Experimentation Of Carbon Nanotubes Using Response Surface Methods, William Adorno Iii
Autonomous Experimentation Of Carbon Nanotubes Using Response Surface Methods, William Adorno Iii
Theses and Dissertations
Advances in hardware and software technology have led to the development of automated research systems. The Air Force Research Laboratory (AFRL) utilizes the Adaptive Rapid Experimentation and Spectroscopy (ARES) system to synthesize carbon nanotubes. The AFRL researchers are investigating different approaches that can improve the experimental capability of ARES from automation to autonomy. Carbon nanotubes are discussed as an emerging technology for many applications, but AFRL has yet to discover what factors optimize the nanotube initial growth rate. In this study, experimental planning software was written for ARES that autonomously designs and executes experiments based on the Response Surface Methodology …
Assessing Gps Constellation Resiliency In An Urban Canyon Environment, Aaron J. Burns
Assessing Gps Constellation Resiliency In An Urban Canyon Environment, Aaron J. Burns
Theses and Dissertations
Satellite constellation resiliency is an important consideration gaining momentum at the top levels of the Air Force and at Air Force Space Command (AFSPC). The increased availability of threats to satellite systems is challenging the capabilities provided by space assets. More specifically, the global positioning system (GPS) satellite constellation is utilized for a variety of missions, to include providing precise geolocation information for navigation. Any degrade in GPS capabilities as observed in an urban canyon environment or due to the loss of a GPS satellite may hinder the overall mission. We use the System Effectiveness Analysis Simulation (SEAS) to model …
Agent-Based Modeling Methodology For Analyzing Weapons Systems, Casey D. Connors
Agent-Based Modeling Methodology For Analyzing Weapons Systems, Casey D. Connors
Theses and Dissertations
Getting as much information as possible to make decisions about acquisition of new weapons systems, through analysis of the weapons systems' benefits and costs, yields better decisions. This study has twin goals. The first is to demonstrate a sound methodology to yield the most information about benefits of a particular weapon system. Second, to provide some baseline analysis of the benefits of a new type of missile, the Small Advanced Capability Missile (SACM) concept, in an unclassified general sense that will help improve further, more detailed, classified investigations into the benefits of this missile. In a simplified, unclassified scenario, we …
A Predictive Logistic Regression Model Of World Conflict Using Open Source Data, Benjamin C. Boekestein
A Predictive Logistic Regression Model Of World Conflict Using Open Source Data, Benjamin C. Boekestein
Theses and Dissertations
Nations transitioning into conflict is an issue of national interest. This study considers various data for inclusion in a statistical model that predicts the future state of the world where nations will either be in a state of violent conflict or not in violent conflict based on available historical data. Logistic regression is used to construct and test various models to produce a parsimonious world model with 15 variables. Further analysis shows that nations differ significantly by geographical area. Therefore six sub-models are constructed for differing geographical areas of the world. The dominant variables for each sub-model vary, suggesting a …
Forecasting Fuels Support Equipment Requisitions, Justin P. D'Agostino
Forecasting Fuels Support Equipment Requisitions, Justin P. D'Agostino
Theses and Dissertations
Within the past two years the Air Force has begun transitioning management of equipment from regionalized management at Command Equipment Management Offices (CEMOs) to centralized enterprise management offices. The fuels support equipment (FSE) inventory is a subcategory of Air Force equipment, the management of which has recently transferred from CEMOs to the Air Force Petroleum Agency (AFPA). Because FSE inventory was previously managed regionally, there is a gap in descriptive data for the enterprise FSE inventory. This study attempts to close this information gap through describing the current inventory position, defining historical FSE demand, and using this knowledge to forecast …
Restoration And Humanitarian Aid Delivery On Interdependent Transportation And Communication Networks After An Extreme Event, Jacob A. Forbes
Restoration And Humanitarian Aid Delivery On Interdependent Transportation And Communication Networks After An Extreme Event, Jacob A. Forbes
Theses and Dissertations
Among the devastating consequences of extreme events, whether natural or manmade, is the disruption of transportation, communication, and other critical infrastructure systems. The restoration of these systems can be especially challenging due to the fact that damaged infrastructures are often characterized by complex interdependencies. Given a region with interdependent transportation and communication networks, both of which have sustained some damage due to an extreme event, we seek to maximize the satisfaction of geographically distributed demands for relief items over time by scheduling work crews to selected restoration tasks and routing the delivery of resources. We develop a mixed-integer linear programming …
The Military Theater Distribution Network Design Problem, Robert R. Craig
The Military Theater Distribution Network Design Problem, Robert R. Craig
Theses and Dissertations
We formulate and test a mathematical program to select Air and Sea Ports of Debarkation and intermediate logistical distribution centers, through which we route military supplies over a directed transportation network to meet aggregated weekly demands by military units conducting a steady state contingency operation. The multi-objective model seeks to minimize a weighted combination of the total risk encountered by transported supplies, the total distance traveled by supplies, and the maximum per capita workload supported by transportation assets at a given echelon (i.e., port-to-distribution center versus distribution center to demands). Within our formulation, we account for capacities on arc follows …
Advancing Cost-Effective Readiness By Improving The Supply Chain Management Of Sparse, Intermittently-Demanded Parts, Gregory H. Gehret
Advancing Cost-Effective Readiness By Improving The Supply Chain Management Of Sparse, Intermittently-Demanded Parts, Gregory H. Gehret
Theses and Dissertations
Many firms generate revenue by successfully operating machines such as welding robots, rental cars, aircraft, hotel rooms, amusement park attractions, etc. It is critical that these revenue-generating machines be operational according to the firm s target or requirement; thus, assuring sustained revenue generation for the firm. Machines can and do fail, and in many cases, restoring the downed machine requires spare part(s), which are typically managed by the supply chain. The scope of this research is on the supply chain management of the very sparse, intermittently-demanded spare parts. These parts are especially difficult to manage because they have little to …
Determining The Most Vital Arcs Within A Multi-Mode Communication Network Using Set-Based Measures, Christopher A. Hergenreter
Determining The Most Vital Arcs Within A Multi-Mode Communication Network Using Set-Based Measures, Christopher A. Hergenreter
Theses and Dissertations
Technology has dramatically changed the way the military has disseminated information over the last fifty years. The Air Force has adapted to the change by operating a network with various ways to disseminate information. The Air Operating Center (AOC) is a large contributor to disseminating information in the Air Force. When the standard mode of sending information is disrupted, the AOC seeks both alternative ways available to send information and long term approaches to decrease vulnerability of its standard procedures. In this thesis, we seek to identify and quantify the most vital components within a multi-mode communications network via a …
An Optimization Of The Maintenance Assets Distribution Network In The Argentine Air Force, Santiago Hernandez
An Optimization Of The Maintenance Assets Distribution Network In The Argentine Air Force, Santiago Hernandez
Theses and Dissertations
The Argentine Air Force Materiel General Directorate is responsible for the supply and distribution of reparable and consumable assets to support the operations of more than thirty different weapons systems. The Materiel General Directorate recently initiated an effort to assure logistic support and to gradually increase the productivity and efficiency of the related processes. The distribution of consumable and reparable assets was a key process identified as inefficient and targeted for improvement, and a recommendation was made to consider organic or private transportation and reduce transportation time in order to improve responsiveness and drive down logistic pipeline costs. This thesis …
Approximate Dynamic Programming Algorithms For United States Air Force Officer Sustainment, Joseph C. Hoecherl
Approximate Dynamic Programming Algorithms For United States Air Force Officer Sustainment, Joseph C. Hoecherl
Theses and Dissertations
The United States Air Force (USAF) officer sustainment system involves making accession and promotion decisions for nearly 64 thousand officers annually. We formulate a discrete time stochastic Markov decision process model to examine this military workforce planning problem. The large size of the motivating problem suggests that conventional exact dynamic programming algorithms are inappropriate. As such, we propose two approximate dynamic programming (ADP) algorithms to solve the problem. We employ a least-squares approximate policy iteration (API) algorithm with instrumental variables Bellman error minimization to determine approximate policies. In this API algorithm, we use a modified version of the Bellman equation …
Overcoming Hurdles Implementing Multi-Skilling Policies, Joshua M. Isom
Overcoming Hurdles Implementing Multi-Skilling Policies, Joshua M. Isom
Theses and Dissertations
Ogden ALC at Hill AFB has been authorized to promote wage grade employees if they are multi-skilled, but that authorization will expire at the end of Fiscal Year 2018. Simulation research by Capt Wesley Sheppard demonstrated significant cost savings/cost avoidance if multi-skilling is pursued, but there are significant challenges to implementation. This research examined two challenges in implementation. First, how many employees can be multi-skilled and still maintain proficiency in both skills? Second, once multi-skilled, is there a technique that can be applied to easily and effectively schedule the new multi-skilled workforce. Using linear programming, staffing numbers were calculated based …
Integrating Agile Combat Support Within Title 10 Wargames, Daniel A. Krievs
Integrating Agile Combat Support Within Title 10 Wargames, Daniel A. Krievs
Theses and Dissertations
Air Force (AF) Concept Development and Experimentation (CD&E) continually progresses the evolution of AF while achieving national security and military objectives. CD&E experiments on future challenges, procurement of new weapon systems and tests existing/innovative strategies as potential solutions. The primary tool that CD&E utilizes in conducting these experiments is wargaming. This thesis provides a foundation to incorporate logistics into Air Force Title 10 wargames. More specifically, we capture Air Force Materiel Command's (AFMC) Agile Combat Support (ACS) within an unclassified general wargame scenario. Logistics has been omitted from wargames for a multitude of reasons throughout the years. We develop a …
Suitability Analysis Of Continuous-Use Reliability Growth Projection Models, Benjamin R. Mayo
Suitability Analysis Of Continuous-Use Reliability Growth Projection Models, Benjamin R. Mayo
Theses and Dissertations
Substandard system reliability is one of the leading causes of increased Operations and Maintenance (O&M) costs as noted in several recent National Research Council reports. Between 2006 and 2011, Director Operational Test & Evaluation noted 26 of 52 Department of Defense acquisition programs failed to meet reliability thresholds, but were approved, leading to degraded operational performance, increased O&M costs, and increased safety risks for personnel involved. As a system is developed from prototype to final product, structural changes and design flaws are corrected, leading to an increase in system reliability, called reliability growth. Due to the nature of the system …
A Risk Based Approach To Node Insertion Within Social Networks, Chancellor A. J. Johnstone
A Risk Based Approach To Node Insertion Within Social Networks, Chancellor A. J. Johnstone
Theses and Dissertations
Social Network Analysis (SNA) is a primary tool for counter-terrorism operations, ranging from resiliency and influence to interdiction on threats stemming from illicit overt and clandestine network operations. In an ideal world, SNA would provide a perfect course of action to eliminate dangerous situations that terrorist organizations bring. Unfortunately, the covert nature of terrorist networks makes the effects of these techniques unknown and possibly detrimental. To avoid potentially harmful changes to enemy networks, tactical involvement must evolve, beginning with the intelligent use of network in filtration through the application of the node insertion problem. The framework for the node insertion …
Cascading Effects Of Fuel Network Interdiction, Jeffrey T. Painter
Cascading Effects Of Fuel Network Interdiction, Jeffrey T. Painter
Theses and Dissertations
This thesis develops the Fuel Interdiction and Resulting Cascading Effects (FI&RCE) model. The study details the development and experimental testing of a framework for assessing the interdiction of a refined petroleum production and distribution network. FI&RCE uses a maximum flow mathematical programming formulation that models the transit of fuels from points of importation and refinement through a polyduct distribution network for delivery across a range of end user locations. The automated model accommodates networks of varying size and complexity. FI&RCE allows for parameters and factor settings that enable robust experimentation through implementation in MATLAB 2014 and the commercial solver CPLEX …
Optimizing The Domestic Chemical, Biological, Radiological, And Nuclear Response Enterprise, Nicholas R. Paul
Optimizing The Domestic Chemical, Biological, Radiological, And Nuclear Response Enterprise, Nicholas R. Paul
Theses and Dissertations
The Chemical Biological Radiological Nuclear (CBRN) Response Enterprise (CRE) exists to rapidly respond to a domestic CBRN attack in order to minimize the overall impact of an incident. Over the past 16 years, the CRE has grown incrementally, and it is unclear if the current locations of units optimizes the coverage of the US population within a rapid response window. In this paper we develop a multi-objective multi-service extension of the maximal covering location problem (MCLP) to analyze the current coverage provided by the CRE and recommend efficient modifications to better protect the American population. While public sector facility location …
Value Focused Thinking Applications To Supervised Pattern Classification With Extensions To Hyperspectral Anomaly Detection Algorithms, David S. Scanland
Value Focused Thinking Applications To Supervised Pattern Classification With Extensions To Hyperspectral Anomaly Detection Algorithms, David S. Scanland
Theses and Dissertations
Hyperspectral imaging (HSI) is an emerging analytical tool with flexible applications in different target detection and classification environments, including Military Intelligence, environmental conservation, etc. Algorithms are being developed at a rapid rate, solving various related detection problems under certain assumptions. At the core of these algorithms is the concept of supervised pattern classification, which trains an algorithm to data with enough generalizability that it can be applied to multiple instances of data. It is necessary to develop a logical methodology that can weigh responses and provide an output value that can help determine an optimum algorithm. This research focuses on …
The Cognition Of Multiaircraft Control (Mac): Cognitive Ability Predictors, Working Memory, Interference, And Attention Control In Radio Communication, Kelly M. Amaddio
The Cognition Of Multiaircraft Control (Mac): Cognitive Ability Predictors, Working Memory, Interference, And Attention Control In Radio Communication, Kelly M. Amaddio
Theses and Dissertations
As the number of U.S. Air Force missions requiring UAVs has rapidly increased without commensurate increases in manpower, systems which permit a single operator to supervise and control multiple, highly-automated aircraft are being considered. The operator of such a system may be required to monitor and respond to voice communications for multiple UAVs, each of which can have aircraft specific call signs. The need to monitor this array of call signs may impose excessive requirements on constrained operator attention, working memory, and cognitive processing. The current research investigates the cognitive load (number of aircraft call signs) an individual can handle …
Functionality, Complexity, And Approaches To Assessment Of Resilience Under Constrained Energy And Information, Jason B. Clark
Functionality, Complexity, And Approaches To Assessment Of Resilience Under Constrained Energy And Information, Jason B. Clark
Theses and Dissertations
While system functions, functionality, and complexity are widely used concepts in systems engineering, there is significant diversity in their definitions and no unified approach to measurement. This research establishes a method for measuring impacts to functionality in dynamic engineered systems based on changes in kinetic energy. This metric is applied at particular levels of abstraction and system scales, consistent with the established multiscale nature of systems. By measuring system behavior in context with expected scenarios, it is possible to estimate expected functionality or set bounds on a system's maximum functionality. Functionality and system effectiveness is heavily influenced by the amount …
Using Earned Value Data To Forecast The Duration Of Department Of Defense (Dod) Space Acquisition Programs, Shedrick M. Bridgeforth
Using Earned Value Data To Forecast The Duration Of Department Of Defense (Dod) Space Acquisition Programs, Shedrick M. Bridgeforth
Theses and Dissertations
The accuracy of cost estimates is vital during this era of budget constraints. A key component of this accuracy is regularly updating the cost estimate at completion (EAC). A 2014 study by the Air Force Cost Analysis Agency (AFCAA) improved the accuracy of the cost estimate at completion (EAC) for space system contracts. The study found schedule duration to be a cost driver, but assumed the underlying duration estimate was accurate. This research attempts to improve the accuracy of the duration estimate from the AFCAA study; accuracy is evaluated with the Mean Absolute Percent Error (MAPE). The methods researched here …
Integrating Pavement Crack Detection And Analysis Using Autonomous Unmanned Aerial Vehicle Imagery, Patrick J. Grandsaert
Integrating Pavement Crack Detection And Analysis Using Autonomous Unmanned Aerial Vehicle Imagery, Patrick J. Grandsaert
Theses and Dissertations
Efficient, reliable data is necessary to make informed decisions on how to best manage aging road assets. This research explores a new method to automate the collection, processing, and analysis of transportation networks using Unmanned Aerial Vehicles and Computer Vision technology. While there are current methodologies to accomplish road assessment manually and semi-autonomously, this research is a proof of concept to obtain the road assessment faster and cheaper with a vision for little to no human interaction required. This research evaluates the strengths of applying UAV technology to pavement assessments and identifies where further work is needed. Furthermore, it validates …
The Effect Of Stages And Levels Of Automation And Reliability On Workload And Performance For Remotely Piloted Aircraft Operations, Stephen P. Katrein
The Effect Of Stages And Levels Of Automation And Reliability On Workload And Performance For Remotely Piloted Aircraft Operations, Stephen P. Katrein
Theses and Dissertations
This thesis investigates incorporating different stages and levels of automation with varying degrees of reliability into a remotely piloted aircraft (RPA) surveillance task in order to determine how automation implementation and reliability affect operator workload and system performance. The study uses IMPRINT discrete event simulation to evaluate three levels of reliability in twelve different baseline automation implementations within a remotely piloted vehicle task. Three stages and four levels are modeled, for a total of twelve combinations, along with a baseline task with no automation. The stages modeled are the information acquisition stage, the decision and action selection stage, and the …
Predicting Citizen Satisfaction With Government Services In Belize, Samuel W. Logan
Predicting Citizen Satisfaction With Government Services In Belize, Samuel W. Logan
Theses and Dissertations
Assessing the effectiveness of humanitarian assistance and foreign aid has presented a challenge to personnel tasked with these operations. Answering the question "are we winning hearts and minds" has similarly eluded military personnel in Iraq and Afghanistan. This research presents a review of humanitarian assistance and foreign aid conducted by the U.S. government and literature on U.S. military doctrine regarding humanitarian assistance and infrastructure investment. The research builds upon expectancy disconfirmation theory to determine the strongest predictors of citizen satisfaction with government services. Case study data was collected in Belize before and after a U.S. military humanitarian and civil assistance …
Parametric Estimation Of Load For Air Force Datacenters, Derek P. Molle
Parametric Estimation Of Load For Air Force Datacenters, Derek P. Molle
Theses and Dissertations
The Office of Management and Budget (OMB) has tasked Federal agencies to develop a Data Center Consolidation Plan. Effective planning requires a repeatable method to effectively and efficiently size Air Force Base-level data centers. Review of commercial literature on data center design found emphasis in power efficiency, thermal modeling and cooling, and network speed and availability. The topic of sizing data center processing capacity seems undeveloped. This thesis provides a better, pedigreed solution to the data center sizing problem. By analogy, Erlang's formulae for the probability of blocking and queuing should be applicable to cumulative CPU utilization in a data …
A Probabilistic Assessment Of Failure For Air Force Building Systems, Stephanie L. Alley
A Probabilistic Assessment Of Failure For Air Force Building Systems, Stephanie L. Alley
Theses and Dissertations
Deteriorating and failing federal facilities represent a cost to leaders and organizations as they attempt to manage and maintain these assets. Currently the Air Force employs the BUILDERTM Sustainment Management System to predict the reliability of building components. At different system levels, however, the probabilities of failure are not predicted. The purpose of this research is to provide probabilistic models which predict the probability of failure at the system level of a building s infrastructure hierarchy. This research investigated the plumbing, HVAC, fire protection, and electrical systems. Probabilistic models were created for these systems by using fault trees with …
Coherent Thermal Emission From Photonic Nanostructures Composed Of Ta, W, Ge, And Hfo2 Thin Films, Mark T. Dodd
Coherent Thermal Emission From Photonic Nanostructures Composed Of Ta, W, Ge, And Hfo2 Thin Films, Mark T. Dodd
Theses and Dissertations
Combining an understanding of thin films and structure/property relationships, photonic nano-structures were developed in order to affect the spectral and directional radiative properties of coherent thermal emission. The targeted emission range was 2-20 µm. Structures with appropriate materials in order to achieve thermal stability were designed and tested. Implementing a Finite Difference Time Domain numerical method, four truncated multilayer resonators were designed to selectively emit at certain transmissive wavelength bands of the atmosphere in 2-20 µm. Ellipsometric measurements and models were used in order to extract the optical constants of thin layers of materials chosen for the resonator designs. These …
A Comparative Study Of Learning Curve Models In Defense Airframe Cost Estimating, Justin R. Moore
A Comparative Study Of Learning Curve Models In Defense Airframe Cost Estimating, Justin R. Moore
Theses and Dissertations
The goal of this research was to identify which learning curve model is most accurate when applied to Defense acquisition programs. Wright's original learning curve model is widely accepted and used within Defense acquisitions, but the 75+ year old model may be outdated. This study compares Wright's model against three alternative learning curve models using total lot costs for the F-15 C/D & E programs: the Stanford-B model, the DeJong learning formula, and the S-Curve model. However, the results of the study are inconclusive. Two of the three alternative models, the DeJong and S-Curve, rely on the use of an …