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Articles 1531 - 1560 of 2678
Full-Text Articles in Physical Sciences and Mathematics
Corporate Entrepreneurship Assessment Instrument (Ceai): Refinement And Validation Of A Survey Measure, Michael S. Cates
Corporate Entrepreneurship Assessment Instrument (Ceai): Refinement And Validation Of A Survey Measure, Michael S. Cates
Theses and Dissertations
The study of corporate entrepreneurship has established itself as a valuable area of research for both public and private-sector organizations. The measurement instrument known as the Corporate Entrepreneurship Assessment Index (CEAI) has been designed to tap the climate-related organizational factors that represent and potentially encourage corporate entrepreneurship. This study is an attempt to refine the CEAI. The core constructs of the CEAI are redefined, the items are tested for content validity, the factor structure is analyzed, and the CEAI is correlated to other known measures to validate the CEAI. Through this testing, the CEAI was refined and found to be …
Surrogate Strategies For Computationally Expensive Optimization Problems With Cpu-Time Correlated Functions, Raymond Magallanez Jr.
Surrogate Strategies For Computationally Expensive Optimization Problems With Cpu-Time Correlated Functions, Raymond Magallanez Jr.
Theses and Dissertations
This research focuses on numerically solving a class of computationally expensive optimization problems that possesses a unique characteristic: as the optimal solution is approached, the computational time required to compute an objective function value decreases. This is motivated by an application in which each objective function evaluation requires both a numerical fluid dynamics simulation and an image registration and comparison process. The goal is to find the parameters of a predetermined image by comparing the flow dynamics from the numerical simulation and the predetermined image through the image comparison process. The generalized pattern search and mesh adaptive direct search methods …
Characterization Of Chlorinated Ethene Degradation In A Vertical Flow Constructed Wetland, James M. Waldron
Characterization Of Chlorinated Ethene Degradation In A Vertical Flow Constructed Wetland, James M. Waldron
Theses and Dissertations
Chlorinated solvents, including perchloroethene (PCE) and trichlorethene (TCE), are among the most common groundwater contaminants found in the United States. Once released into the environment, chlorinated solvents are extremely persistent and often require costly and lengthy remedial actions. The use of constructed wetlands has shown promise as an effective and less costly alternative for the treatment of chlorinated solvent contaminated groundwater. This study characterized and evaluated the concentration of chlorinated ethenes within a vertical flow constructed wetland, fed with PCE contaminated groundwater, at Wright-Patterson Air Force Base (WPAFB), Ohio. Chlorinated ethene concentrations were characterized within three distinct layers of the …
A Meta-Analysis Of Questionaire Response Rates In Military Samples, Michael R. Parrish
A Meta-Analysis Of Questionaire Response Rates In Military Samples, Michael R. Parrish
Theses and Dissertations
The purpose of this research was to examine if factors related to questionnaire response rate in the general public also affect response rate in military-only samples. Very little research pertaining to this specific group was located during the literature review. Four response rate factors taken from studies conducted in the general public were selected for this research topic: questionnaire length, questionnaire delivery mode (postal, e-mail, web-based, direct administration, and mixed mode), use of advance notices, and use of follow-up reminders. Data were gathered for a meta-analysis of 73 previously published studies which utilized a survey or questionnaire to collect data …
Unified Behavior Framework For Reactive Robot Control In Real-Time Systems, Brian G. Woolley
Unified Behavior Framework For Reactive Robot Control In Real-Time Systems, Brian G. Woolley
Theses and Dissertations
Endeavors in mobile robotics focus on developing autonomous vehicles that operate in dynamic and uncertain environments. By reducing the need for human-in- the-loop control, unmanned vehicles are utilized to achieve tasks considered dull or dangerous by humans. Because unexpected latency can adversely affect the quality of an autonomous system's operations, which in turn can affect lives and property in the real-world, their ability to detect and handle external events is paramount to providing safe and dependable operation. Behavior-based systems form the basis of autonomous control for many robots. This thesis presents the unified behavior framework, a new and novel approach …
Modeling, Simulation, And Estimation Of Optical Turbulence, Byron P. Formwalt
Modeling, Simulation, And Estimation Of Optical Turbulence, Byron P. Formwalt
Theses and Dissertations
This dissertation documents three new contributions to simulation and modeling of optical turbulence. The first contribution is the formalization, optimization, and validation of a modeling technique called successively conditioned rendering (SCR). The SCR technique is empirically validated by comparing the statistical error of random phase screens generated with the technique. The second contribution is the derivation of the covariance delineation theorem, which provides theoretical bounds on the error associated with SCR. It is shown empirically that the theoretical bound may be used to predict relative algorithm performance. Therefore, the covariance delineation theorem is a powerful tool for optimizing SCR algorithms. …
Using Value-Focused Thinking To Evaluate The Use Of Innovative Stormwater Management Technologies On Air Force Installations, Jeffrey T. Falcone
Using Value-Focused Thinking To Evaluate The Use Of Innovative Stormwater Management Technologies On Air Force Installations, Jeffrey T. Falcone
Theses and Dissertations
Stormwater runoff occurs naturally after every storm event; however, traditional development practices have created many impervious surfaces, such as buildings, parking lots, and streets that increase runoff volume and flow rate. Conventional stormwater management practices focus on collecting runoff into centralized channels and conveying it as quickly as possible to local bodies of water. This type of conveyance system decreases the opportunity for stormwater to naturally infiltrate back into the ground. It also prevents contaminants from being naturally filtered out of stormwater flows. As a result, centralized conveyance systems can cause flooding, erosion, and terrestrial and aquatic habitat degradation. Innovative …
Recommendations For A Standardized Program Management Office (Pmo) Time Compliance Network Order (Tcno) Patching Process, Michael Czumak Iii
Recommendations For A Standardized Program Management Office (Pmo) Time Compliance Network Order (Tcno) Patching Process, Michael Czumak Iii
Theses and Dissertations
Network security is a paramount concern for organizations utilizing computer technology, and the Air Force is no exception. Network software vulnerability patching is a critical determinant of network security. The Air Force deploys these patches as Time Compliance Network Orders (TCNOs), which together with associated processes and enforced timelines ensure network compliance. While the majority of the network assets affected by this process are Air Force owned and operated, a large number are maintained by external entities known as Program Management Offices (PMOs). Although these externally controlled systems provide a service to the Air Force and reside on its network, …
Microbial Degradation Of Fuel Oxygenates Under Aerobic Conditions, John M. Dietz
Microbial Degradation Of Fuel Oxygenates Under Aerobic Conditions, John M. Dietz
Theses and Dissertations
This research determined the rate and extent of aerobic biodegradation of fuel oxygenates ethyl tert butyl ether (ETBE), tert amyl methyl ether (TAME), and ethyl alcohol (ethanol). Biodegradation was measured using gas chromatography (GC), respirometry, and biochemical oxygen demand (BOD) tests. Additionally, the research determined the effects of toluene on degradation rates. This microcosm study used a microbial consortium obtained from a petroleum refinery wastewater treatment facility. Respirometry data were collected from chambers containing pure oxygenates, or oxygenate/toluene mixtures. Samples were withdrawn periodically for GC analysis. Aerobic conditions were maintained in the chambers at all times. The five-day BOD test …
Improved Hyperspectral Image Testing Using Synthetic Imagery And Factorial Designed Experiments, Joseph P. Bellucci
Improved Hyperspectral Image Testing Using Synthetic Imagery And Factorial Designed Experiments, Joseph P. Bellucci
Theses and Dissertations
The goal of any remote sensing system is to gather data about the geography it is imaging. In order to gain knowledge of the earth's landscape, post-processing algorithms are developed to extract information from the collected data. The algorithms can be intended to classify the various ground covers in a scene, identify specific targets of interest, or detect anomalies in an image. After the design of an algorithm comes the difficult task of testing and evaluating its performance. Traditionally, algorithms are tested using sets of extensively ground truthed test images. However, the lack of well characterized test data sets and …
Software Protection Against Reverse Engineering Tools, Joshua A. Benson
Software Protection Against Reverse Engineering Tools, Joshua A. Benson
Theses and Dissertations
Advances in technology have led to the use of simple to use automated debugging tools which can be extremely helpful in troubleshooting problems in code. However, a malicious attacker can use these same tools. Securely designing software and keeping it secure has become extremely difficult. These same easy to use debuggers can be used to bypass security built into software. While the detection of an altered executable file is possible, it is not as easy to prevent alteration in the first place. One way to prevent alteration is through code obfuscation or hiding the true function of software so as …
Towards The Development Of A Defensive Cyber Damage And Mission Impact Methodology, Larry W. Fortson Jr.
Towards The Development Of A Defensive Cyber Damage And Mission Impact Methodology, Larry W. Fortson Jr.
Theses and Dissertations
The purpose of this research is to establish a conceptual methodological framework that will facilitate effective cyber damage and mission impact assessment and reporting following a cyber-based information incidents. Joint and service guidance requires mission impact reporting, but current efforts to implement such reporting have proven ineffective. This research seeks to understand the impediments existing in the current implementation and to propose an improved methodology. The research employed a hybrid historical analysis and case study methodology for data collection through extensive literature review, examination of existing case study research and interviews with Air Force members and civilian personnel employed as …
Predicting Argentine Jet Fuel Prices, Juan A. Salaverry
Predicting Argentine Jet Fuel Prices, Juan A. Salaverry
Theses and Dissertations
Oil distillates are considered important elements to accomplish the missions of the Argentine Air Force (AAF). Of all oil products consumed by the AAF, jet fuel is the resource with highest demand and at the end of the day the most expensive support item procured by the Argentine Air Force. Accurate predictions of Argentine jet fuel prices are necessary to improve AAF financial and logistics planning. This thesis presents a systematic, statistical regression approach to forecast Argentine jet fuel prices. The application of this methodology has allowed us to obtain a very useful model that utilizes information available on the …
An Evaluation Of Organizational And Experience Factors Affecting The Perceived Transfer Of U.S. Air Force Basic Combat Skills Training, Shirley D. Crow
An Evaluation Of Organizational And Experience Factors Affecting The Perceived Transfer Of U.S. Air Force Basic Combat Skills Training, Shirley D. Crow
Theses and Dissertations
The United States Air Force is in a state of transformation. Due to ongoing operations in Iraq and Afghanistan, the focus of Basic Military Training is shifting to basic combat skills, or the skills needed to survive and operate in a hostile environment. In this study, basic combat skills training was evaluated using a number of training factors that potentially affect trainees’ perception of training transfer, or their ability to apply the skills they learned in training on the job or in a hostile environment. The analysis used structural equation modeling to evaluate the paths between each of the factors …
On-Demand Key Distribution For Mobile Ad-Hoc Networks, Daniel F. Graham
On-Demand Key Distribution For Mobile Ad-Hoc Networks, Daniel F. Graham
Theses and Dissertations
Mobile ad-hoc networks offer dynamic portable communication with little or no infrastructure. While this has many benefits, there are additional shortcomings specific to wireless communication that must be addressed. This research proposes gossip-based on-demand key distribution as a means to provide data encryption for mobile ad-hoc networks. This technique uses message keys to avoid encrypting and decrypting a message at every node. Other optimizations used include secure channel caching and joint rekey messages. The use of gossip makes the scheme robust to node failure. Experimental results show only a 15% increase in end-to-end delay with a node failure rate of …
Stochastic Estimation And Control Of Queues Within A Computer Network, Nathan C. Stuckey
Stochastic Estimation And Control Of Queues Within A Computer Network, Nathan C. Stuckey
Theses and Dissertations
An extended Kalman filter is used to estimate size and packet arrival rate of network queues. These estimates are used by a LQG steady state linear perturbation PI controller to regulate queue size within a computer network. This paper presents the derivation of the transient queue behavior for a system with Poisson traffic and exponential service times. This result is then validated for ideal traffic using a network simulated in OPNET. A more complex OPNET model is then used to test the adequacy of the transient queue size model when non-Poisson traffic is combined. The extended Kalman filter theory is …
Multi-Robot Fastslam For Large Domains, Choyong G. Koperski
Multi-Robot Fastslam For Large Domains, Choyong G. Koperski
Theses and Dissertations
For a robot to build a map of its surrounding area, it must have accurate position information within the area, and to obtain accurate position information within the area, the robot needs to have an accurate map of the area. This circular problem is the Simultaneous Localization and Mapping (SLAM) problem. An efficient algorithm to solve it is FastSLAM, which is based on the Rao-Blackwellized particle filter. FastSLAM solves the SLAM problem for single-robot mapping using particles to represent the posterior of the robot pose and the map. Each particle of the filter possesses its own global map which is …
Performance Evaluation Of Ad Hoc Routing In A Swarm Of Autonomous Aerial Vehicles, Matthew T. Hyland
Performance Evaluation Of Ad Hoc Routing In A Swarm Of Autonomous Aerial Vehicles, Matthew T. Hyland
Theses and Dissertations
This thesis investigates the performance of three mobile ad hoc routing protocols in the context of a swarm of autonomous unmanned aerial vehicles (UAVs). It is proposed that a wireless network of nodes having an average of 5.1774 log n neighbors, where n is the total number of nodes in the network, has a high probability of having no partitions. By decreasing transmission range while ensuring network connectivity, and implementing multi-hop routing between nodes, spatial multiplexing is exploited whereby multiple pairs of nodes simultaneously transmit on the same channel. The proposal is evaluated using the Greedy Perimeter Stateless Routing (GPSR), …
Analysis Of Routing Worm Infection Rates On An Ipv4 Network, James Gorsuch
Analysis Of Routing Worm Infection Rates On An Ipv4 Network, James Gorsuch
Theses and Dissertations
Malicious logic, specifically worms, has caused monetary expenditure problems to network users in the past. Worms, like Slammer and Code Red, have infected thousands of systems and brought the Internet to a standstill. This research examines the ability of the original Slammer worm, the Slammer based routing worm proposed by Zou et al, and a new Single Slash Eight (SSE) routing worm proposed by this research to infect vulnerable systems within a given address space. This research investigates the Slammer worm's ability to generate a uniform random IP addresses in a given address space. Finally, a comparison of the speed …
Classifying Failing States, Nathan E. Nysether
Classifying Failing States, Nathan E. Nysether
Theses and Dissertations
The US is heavily involved in the first major war of the 21st Century -- The Global War on Terror (GWOT). As with any militant group, the foundation of the enemy's force is their people. There are two primary strategies for defeating the terrorists and achieving victory in the GWOT. First, we must root out terrorists where they live, train, plan, and recruit and attack them militarily. Second, we must suffocate them by cutting off the supply of new soldiers willing to choose aggression or even death over their current life. This thesis helps to achieve these objectives by applying …
Use Of A Continuous Wave Raman Fiber Laser In Graded-Index Multimode Fiber For Srs Beam Combination, Nathan B. Terry, Kevin T. Engel, Thomas G. Alley, Timothy H. Russell
Use Of A Continuous Wave Raman Fiber Laser In Graded-Index Multimode Fiber For Srs Beam Combination, Nathan B. Terry, Kevin T. Engel, Thomas G. Alley, Timothy H. Russell
Faculty Publications
We report using a Raman fiber laser (RFL) based on a multimode graded-index fiber as a novel method for beam combination of two continuous wave pump beams. Due to stimulated Raman scattering, the RFL generates a Stokes beam which can be up to 300% brighter than the pump beams. Up to 5.8 W of Stokes power is generated with an optical conversion efficiency of 56%.
Cybercraft: Protecting Electronic Systems With Lightweight Agents, Daniel R. Karrels, Gilbert L. Peterson
Cybercraft: Protecting Electronic Systems With Lightweight Agents, Daniel R. Karrels, Gilbert L. Peterson
Faculty Publications
The United States military is seeking new and innovative methods for securing and maintaining its computing and network resources locally and world-wide. This document presents a work-in-progress research thrust toward building a system capable of meeting many of the US military’s network security and sustainment requirements. The system is based on a Distributed Multi-Agent System (DMAS), that is secure, small, and scalable to the large networks found in the military. It relies on a staged agent architecture capable of dynamic configuration to support changing mission environments. These agents are combined into Hierarchical Peer-to-Peer (HP2P) networks to provide scalable solutions. They …
Steganalysis Embedding Percentage Determination With Learning Vector Quantization, Benjamin M. Rodriguez, Gilbert L. Peterson, Kenneth W. Bauer, Sos S. Agaian
Steganalysis Embedding Percentage Determination With Learning Vector Quantization, Benjamin M. Rodriguez, Gilbert L. Peterson, Kenneth W. Bauer, Sos S. Agaian
Faculty Publications
Steganography (stego) is used primarily when the very existence of a communication signal is to be kept covert. Detecting the presence of stego is a very difficult problem which is made even more difficult when the embedding technique is not known. This article presents an investigation of the process and necessary considerations inherent in the development of a new method applied for the detection of hidden data within digital images. We demonstrate the effectiveness of learning vector quantization (LVQ) as a clustering technique which assists in discerning clean or non-stego images from anomalous or stego images. This comparison is conducted …
Theory Of Effectiveness Measurement, Richard K. Bullock
Theory Of Effectiveness Measurement, Richard K. Bullock
Theses and Dissertations
Effectiveness measures provide decision makers feedback on the impact of deliberate actions and affect critical issues such as allocation of scarce resources, as well as whether to maintain or change existing strategy. Currently, however, there is no formal foundation for formulating effectiveness measures. This research presents a new framework for effectiveness measurement from both a theoretical and practical view. First, accepted effects-based principles, as well as fundamental measurement concepts are combined into a general, domain independent, effectiveness measurement methodology. This is accomplished by defining effectiveness measurement as the difference, or conceptual distance from a given system state to some reference …
Statistical Approach To Background Subtraction For Production Of High-Quality Silhouettes For Human Gait Recognition, Jennifer J. Samler
Statistical Approach To Background Subtraction For Production Of High-Quality Silhouettes For Human Gait Recognition, Jennifer J. Samler
Theses and Dissertations
This thesis uses a background subtraction to produce high-quality silhouettes for use in human identification by human gait recognition, an identification method which does not require contact with an individual and which can be done from a distance. A statistical method which reduces the noise level is employed resulting in cleaner silhouettes which facilitate identification. The thesis starts with gathering video data of individuals walking normally across a background scene. From there the video is converted into a sequence of images that are stored as joint photographic experts group (jpeg) files. The background is subtracted from each image using a …
New Tracking Filter Algorithm Using Input Parameter Estimation, Corey M. Broussard
New Tracking Filter Algorithm Using Input Parameter Estimation, Corey M. Broussard
Theses and Dissertations
A new method for the design of tracking filters for maneuvering targets, based on kinematic models and input signals estimation, is developed. The input signal's level, u is considered a continuous variable and consequently the input estimation problem is posed as a purely parameter estimation problem. Moreover, the application of the new tracking filter algorithm is not contingent on distinguishing maneuvering and non-maneuvering targets, and does not require the detection of maneuver onset. The filter will automatically detect the onset of a maneuver. Furthermore, an estimate of the target's acceleration is also obtained with reasonable precision. This opens the door …
Optimizing The Replication Of Multi-Quality Web Applications Using Aco And Wolf, Judson C. Dressler
Optimizing The Replication Of Multi-Quality Web Applications Using Aco And Wolf, Judson C. Dressler
Theses and Dissertations
This thesis presents the adaptation of Ant Colony Optimization to a new NP-hard problem involving the replication of multi-quality database-driven web applications (DAs) by a large application service provider (ASP). The ASP must assign DA replicas to its network of heterogeneous servers so that user demand is satisfied and replica update loads are minimized. The algorithm proposed, AntDA, for solving this problem is novel in several respects: ants traverse a bipartite graph in both directions as they construct solutions, pheromone is used for traversing from one side of the bipartite graph to the other and back again, heuristic edge values …
Fast Scene Based Nonuniformity Correction With Minimal Temporal Latency, Christopher A. Rice
Fast Scene Based Nonuniformity Correction With Minimal Temporal Latency, Christopher A. Rice
Theses and Dissertations
The focus of this research was to derive a new algorithm for correction of gain nonuniformities in LIDAR focal plane arrays using as few frames as possible. Because of the current low production rate of LIDAR focal plane arrays there is a natural tendency for extreme nonuniformities to exist on a pixel by pixel basis as the manufacturing technique has not yet been perfected. Generally, nonuniformity correction techniques require a large number of frames and/or have obscure requirements on the translational shifts in the input image frames. This thesis presents a solution for finding multiplicative nonuniformities that exist in a …
Existence Of Large Solutions To Semilinear Elliptic Equations With Multiple Terms, David N. Smith
Existence Of Large Solutions To Semilinear Elliptic Equations With Multiple Terms, David N. Smith
Theses and Dissertations
We consider the semilinear elliptic equation Δu = p(x)uα + q(x)uβ on a domain Ω ⊆ Rn, n ≥ 3, where p and q are nonnegative continuous functions with the property that each of their zeroes is contained in a bounded domain Ωp or Ωq, respectively in Ω such that p is positive on the boundary of Ωp and q is positive on the boundary of Ωq. For Ω bounded, we show that there exists a nonnegative solution u such that u(x) → ∞ as x → ∂Ω if …
Development And Testing Of A High-Speed Real-Time Kinematic Precise Dgps Positioning System Between Two Aircraft, Christopher J. Spinelli
Development And Testing Of A High-Speed Real-Time Kinematic Precise Dgps Positioning System Between Two Aircraft, Christopher J. Spinelli
Theses and Dissertations
This research involves the design, implementation, and testing of a high-speed, real-time kinematic, precise differential GPS positioning system for use in airborne applications such as automated aerial-refueling and close formation flying. Although many of the current ambiguity resolution techniques use the residuals from the least squares position estimation to determine the true ambiguity set, this thesis presents a novel approach to the ambiguity resolution problem, called the minimum indicator. Instead of assuming the ambiguity set with the lowest residuals is the true set, other special characteristics of the residuals are examined. This increases the confidence that the algorithm has selected …