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Articles 6271 - 6300 of 8341
Full-Text Articles in Physical Sciences and Mathematics
Geospatial Informational Security Risks And Concerns Of The U.S. Air Force Geobase Program, Scott A. Bryant
Geospatial Informational Security Risks And Concerns Of The U.S. Air Force Geobase Program, Scott A. Bryant
Theses and Dissertations
Technological advancements such as Geospatial Information Systems (GIS) and the Internet have made it easier and affordable to share information, which enables complex and time sensitive decisions to be made with higher confidence. Further, advancements in information technology have dramatically increased the ability to store, manage, integrate, and correlate larger amounts of data to improve operational efficiency. However, the same technologies that enable increased productivity also provide increased capabilities to those wishing to do harm. Today’s military leaders are faced with the challenge of deciding how to make geospatial information collected on military installations and organizations available to authorized communities …
Pre-Historic Landslides On The Southeast Flank Of The Uinta Mountains, Utah: Character And Causes Of Slope Failure, Todd D. Bradfield
Pre-Historic Landslides On The Southeast Flank Of The Uinta Mountains, Utah: Character And Causes Of Slope Failure, Todd D. Bradfield
Theses and Dissertations
More than 100 landslides have been mapped along the southeast flank of the Uinta Mountains. Large landslide deposits are up to 4.6 kilometers long and have an area of approximately 5-9 km². Landslide types include multiple and successive rock slumps, debris slumps and debris flows. Most landslides have a main head scarp in the Bishop Conglomerate and the large landslides have many minor scarps. Multiple slump blocks are manifest by repeated transverse ridges and trenches in the head area of some landslides. Most body and toe areas are deeply incised by gully erosion (up to 91 meters deep) and drainages …
Adaptive Gravitational Gossip In Monitoring The Joint Battlespace Infosphere, Edmund Descartes Aban
Adaptive Gravitational Gossip In Monitoring The Joint Battlespace Infosphere, Edmund Descartes Aban
Theses and Dissertations
Future USAF operations will be heavily dependent on having the "right information" at the "right time," and Joint Battlespace Infospheres (JBIs) are poised to fill that role. To do this, JBIs must be ubiquitous -- always accessible, secure and responsive. Of all the literature written regarding JBIs, the most important problem to solve in order to make JBIs work in mobile scenarios are scalability, reliability and adaptability to changing battlefield conditions. This paper explores the use of SBCast, a novel adaptive probabilistic protocol and a delivery mechanism for JBI updates and as a possible solution towards guaranteeing these qualities. It …
Structural Analysis Of Rock Canyon Near Provo, Utah, Laura Cardon Wald
Structural Analysis Of Rock Canyon Near Provo, Utah, Laura Cardon Wald
Theses and Dissertations
A detailed structural study of Rock Canyon (near Provo, Utah) provides insight into Wasatch Range tectonics and fold-thrust belt kinematics. Excellent exposures along the E-W trending canyon allow the use of digital photography in conjunction with traditional field methods for a thorough analysis of Rock Canyon's structural features. Detailed photomontages and geometric and kinematic analyses of some structural features help to pinpoint deformation mechanisms active during the canyon's tectonic history. Large-scale images and these structural data are synthesized in a balanced cross section, which is used to reconstruct the structural evolution of this portion of the range. Projection of surficial …
Stimulated Brillouin Scattering Beam Cleanup And Beam Phasing Through Two Passive Channels, Omar Gamboa
Stimulated Brillouin Scattering Beam Cleanup And Beam Phasing Through Two Passive Channels, Omar Gamboa
Theses and Dissertations
Stimulated Brillouin scattering (SBS) beam cleanup and SBS piston correction properties are explored. This research measures the beam cleaning and phase-conjugating properties of stimulated Brillouin scattering in an optical fiber. The first stage of this research began by coupling an aberrated beam into a long multimode 62.5 micron core fiber to demonstrate its beam cleanup properties. The Stokes beam obtained was shown to be the fundamental fiber mode, LP01. The second stage spatially divided the pump beam into two equal halves. Each half was then sent through two different channels. The path length of one channel remained fixed while the …
Assessment Of The Impact Of Various Ionospheric Models On High Frequency Signal Raytracing, Joshua T. Werner
Assessment Of The Impact Of Various Ionospheric Models On High Frequency Signal Raytracing, Joshua T. Werner
Theses and Dissertations
An assessment of the impact of various ionospheric models on high-frequency (HF) signal raytracing is presented. Ionospheric refraction can strongly affect the propagation of HF signals. Consequently, Department of Defense missions such as over-the-horizon RADAR, HF communications, and geo-location all depend on an accurate specification of the ionosphere. Five case studies explore ionospheric conditions ranging from quiet conditions to solar flares and geomagnetic storms. It is shown that an E layer by itself can increase an HF signal’s ground range by over 100 km, stressing the importance of accurately specifying the lower ionosphere. It is also shown that the GPSII …
Spacecraft Proximity Operations Used To Estimate The Dynamical & Physical Properties Of A Resident Space Object, Abraham F. Brunner
Spacecraft Proximity Operations Used To Estimate The Dynamical & Physical Properties Of A Resident Space Object, Abraham F. Brunner
Theses and Dissertations
When conducting a space proximity operation, developing high-fidelity estimates of the dynamical and physical properties of a Resident Space Object (RSO) based on post-rendezvous observational data acquired, is imperative for the understanding of the RSO itself and the operating environment. This research investigates the estimation of relative motion dynamics, rotational dynamics, and the feasibility of estimating the moments of inertia of a RSO. Using the Hill-Clohessy-Wiltshire equations, rigid-body dynamics, and estimation theory, a nonlinear least squares estimation algorithm is implemented in the processing of range data from tracked observation points on the RSO body. Through simulation, it was determined that …
Anisotropy In The South Atlantic Anomaly, Shaun M. Easley
Anisotropy In The South Atlantic Anomaly, Shaun M. Easley
Theses and Dissertations
From June 2000 through July 2006, the TSX-5 satellite measured proton fluxes in the Earth’s magnetosphere using its CEASE instrument. A review of the satellite data by scientists at AFRL/VSBX revealed an unanticipated, recurring bi-modal structure in histograms of the proton counts. This research identified the bi-modal behavior as anisotropic in nature, and the result of two separate processes. At low altitudes the anisotropy was well described by the classic “East-West Effect.” Comparisons of the satellite data to simple analytical models are presented. At high altitudes, the anisotropy was the result of the detector measuring protons at different pitch angles …
The Origins Of Four Paterae Of Malea Planum, Mars, Susan K. Larson
The Origins Of Four Paterae Of Malea Planum, Mars, Susan K. Larson
Theses and Dissertations
Malea Planum is a volcanic plain on the southern rim of Hellas Planitia, the largest impact basin on Mars. Four large circular structures on Malea Planum have traditionally been identified as paterae, or low relief, central vent volcanoes (Plescia and Saunders, 1979). A geologic map was constructed and new crater counts made to explore the ages and origins of the paterae. Amphitrites and Peneus Paterae have radial patterns of wrinkle ridges on their flanks and distinct summit calderas (95 km and 130 km across) with arcuate bounding scarps. In contrast, Malea and Pityusa Paterae are broad depressions with diameters greater …
Portable Diode Pumped Femtosecond Laser, David A. Jones
Portable Diode Pumped Femtosecond Laser, David A. Jones
Theses and Dissertations
This thesis discusses the work to make ultrashort pulsed lasers smaller and more economical. While sharing many of the basic properties of normal beam optics there are some specific properties in both creating and exploiting those pulses that must be understood. The discussion will focus on mode locking as the primary way of producing ultrashort pulses. Particular attention will be paid to intracavity group velocity dispersion and how to correct it inside the cavity. The discussion then turns to the basis of our work including initial cavity design and component selection with focus on the specific crystals used in the …
Development Of A Screening Model For Design And Costing Of An Innovative Tailored Granular Activated Carbon Technology To Treat Perchlorate-Contaminated Water, William C. Powell
Development Of A Screening Model For Design And Costing Of An Innovative Tailored Granular Activated Carbon Technology To Treat Perchlorate-Contaminated Water, William C. Powell
Theses and Dissertations
Perchlorate contamination of drinking water is a problem that has recently gained national attention. The purpose of this research was to develop a tool to predict the cost and performance of tailored granular activated carbon (T-GAC), an innovative technology to treat perchlorate-contaminated water. The ability to predict cost and performance is essential to promote transfer and commercialization of innovative technologies. This study investigated how data obtained from small-scale laboratory tests could be applied to predict cost and performance of a full-scale T-GAC system to treat perchlorate-contaminated water. A technology model was developed using GAC design principles and using a multi-component …
Use Of Tabu Search In A Solver To Map Complex Networks Onto Emulab Testbeds, Jason E. Macdonald
Use Of Tabu Search In A Solver To Map Complex Networks Onto Emulab Testbeds, Jason E. Macdonald
Theses and Dissertations
The University of Utah's solver for the testbed mapping problem uses a simulated annealing metaheuristic algorithm to map a researcher's experimental network topology onto available testbed resources. This research uses tabu search to find near-optimal physical topology solutions to user experiments consisting of scale-free complex networks. While simulated annealing arrives at solutions almost exclusively by chance, tabu search incorporates the use of memory and other techniques to guide the search towards good solutions. Both search algorithms are compared to determine whether tabu search can produce equal or higher quality solutions than simulated annealing in a shorter amount of time. It …
Optical Tracking For Relative Positioning In Automated Aerial Refueling, James H. Spencer
Optical Tracking For Relative Positioning In Automated Aerial Refueling, James H. Spencer
Theses and Dissertations
An algorithm is designed to extract features from video of an air refueling tanker for use in determining the precise relative position of a receiver aircraft. The algorithm is based on receiving a known estimate of the tanker aircraft's position and attitude. The algorithm then uses a known feature model of the tanker to predict the location of those features on a video frame. A corner detector is used to extract features from the video. The measured corners are then associated with known features and tracked from frame to frame. For each frame, the associated features are used to calculate …
A Study Of Bi-Directional Reflectance Distribution Functions And Their Effects On Infrared Signature Models, Samuel I. Harkiss
A Study Of Bi-Directional Reflectance Distribution Functions And Their Effects On Infrared Signature Models, Samuel I. Harkiss
Theses and Dissertations
Since 2004, AFIT has been developing a trend-analysis tool to assess large commercial aircraft infrared (LCAIR) signatures. In many cases, this code predicted signatures to within 10% of measured data. However, other results indicated that the single-bounce, specular-reflection algorithm being used failed to adequately simulate interactions between aircraft parts where either the specular component is dominated by diffuse reflection or part-to-part multiple-bounce reflections contribute significantly to the signature. This research incorporates Bi-Directional Reflectance Distribution Functions (BRDF's) and multiple-bounce calculations into the LCAIR model. A physical aircraft model was constructed from aluminum, and measurements were taken before and after a surface …
Improving Machine Learning Through Oracle Learning, Joshua Ephraim Menke
Improving Machine Learning Through Oracle Learning, Joshua Ephraim Menke
Theses and Dissertations
The following dissertation presents a new paradigm for improving the training of machine learning algorithms, oracle learning. The main idea in oracle learning is that instead of training directly on a set of data, a learning model is trained to approximate a given oracle's behavior on a set of data. This can be beneficial in situations where it is easier to obtain an oracle than it is to use it at application time. It is shown that oracle learning can be applied to more effectively reduce the size of artificial neural networks, to more efficiently take advantage of domain experts …
Refinement Of An Instrument To Assess Readiness For Knowledge Management, Landon C. Bailey
Refinement Of An Instrument To Assess Readiness For Knowledge Management, Landon C. Bailey
Theses and Dissertations
Academics and practitioners have described knowledge as a primary source for competitive advantage for organizations; however, many attempts at instituting knowledge management programs to increase organizational competitiveness do not succeed. Instituting knowledge management programs generally requires organizations to make significant changes and the concept of readiness has long been believed to be an important precondition for successful organizational change. By linking previous research in enablers for knowledge management and organizational change, it is possible to adapt an established organizational change readiness instrument to measure readiness for knowledge management. This study culminates in the development and field-testing of the resultant knowledge …
The Effects Of Orthophosphate As A Copper Corrosion Control Inhibitor In High Alkalinity Drinking Water Systems, Stephen Grace
The Effects Of Orthophosphate As A Copper Corrosion Control Inhibitor In High Alkalinity Drinking Water Systems, Stephen Grace
Theses and Dissertations
The purpose of this research was to investigate orthophosphate as a corrosion inhibitor for copper pipe in a high-alkalinity drinking water system. Specifically, this thesis sought to answer three research questions regarding the impact of orthophosphate treatment, the nature of the mechanism by which orthophosphate controls copper corrosion, and the value of equilibrium modeling in predicting orthophosphate’s effects. The research questions were answered through a comprehensive literature review and experimental methodology integrating laboratory jar tests, water sampling and analysis from a field investigation, qualitative solids analysis, and equilibrium model application. This study analyzed field data obtained over the course of …
Obstacle Annotation By Demonstration, Michael David Clement
Obstacle Annotation By Demonstration, Michael David Clement
Theses and Dissertations
By observing human driving with a “digital head" (combined video camera and accelerometers) and taking a few hand annotations, we can automatically annotate regions in a robot's field of view that should be interpreted as obstacles to be avoided. This is accomplished by detecting the movement for a given frame in a video. Some hand annotations of video frames are necessary and they are used to create Probability Grids. Using the movement data and the Probability Grids, it is possible to annotate large amounts of video data quickly in an automated system.
Pyridinium Bis-Retinoids: Extraction, Synthesis, And Folate Coupling, Mary Allison Alvarez
Pyridinium Bis-Retinoids: Extraction, Synthesis, And Folate Coupling, Mary Allison Alvarez
Theses and Dissertations
This thesis is divided into two parts.Part I describes the organic extraction, separation, and liquid chromatographic-mass spectrometric analysis of chromophores from human and bovine retinal pigment epithelium. Flurorophores in the retinal pigment epithelium have been implicated in age related macular degeneration. In addition, the synthesis and characterization of a number of bis-retinoid type compounds that may potentially be found in such extracts, or that may be used for insight into pyridinium bis-retinoid reactivity, was accomplished.Part II describes a study of pyridinium bis-retinoid-folic acid coupling with respect to linker type, linker length, and nature of the linkage. Folic acid has been …
The Effect Of Birth Order On Infant Injury, Heather L. Van Duker
The Effect Of Birth Order On Infant Injury, Heather L. Van Duker
Theses and Dissertations
Pediatric injury is both common and expensive. Finding ways to prevent pediatric injury is a major public health concern. Many studies have investigated various aspects of pediatric injury, and some suggest that birth order may be an important risk factor for pediatric injury. This study further examined the relationship of birth order with pediatric injury, specifically studying the association of birth order with emergency department-attended infant injury while adjusting for other important family and individual covariates. Data for analysis included Utah birth certificate, death certificate, and hospital emergency department datasets, which were probabilistically linked to obtain complete demographic and injury …
Using Concept Maps To More Efficiently Create Intelligence Information Models, Christopher E. Coryell
Using Concept Maps To More Efficiently Create Intelligence Information Models, Christopher E. Coryell
Theses and Dissertations
Information models are a critical tool that enables intelligence customers to quickly and accurately comprehend U.S. intelligence agency products. The Knowledge Pre-positioning System (KPS) is the standard repository for information models at the National Air and Space Intelligence Center (NASIC). The current approach used by NASIC to build a KPS information model is laborious and costly. Intelligence analysts design an information model using a manual, butcher-paper-based process. The output of their work is then entered into KPS by either a single NASIC KPS "database modeler" or a contractor (at a cost of roughly $100K to the organization). This thesis proposes …
Use Of Thrust Vectors In Support Of The Cybercraft Initiative, Michael Stevens
Use Of Thrust Vectors In Support Of The Cybercraft Initiative, Michael Stevens
Theses and Dissertations
The CyberCraft Initiative is designing a framework for command and control of future Air Force Cyber-weapon systems, that autonomously operate and defend the Air Force networks and information systems to provide Cyberspace Superiority in support of the defense of the United States. The fundamental research question of the CyberCraft Initiative is "What is required for a commander to trust a CyberCraft to autonomously defend military information systems?" The Trust Vector model is one method of integrating trust into the CyberCraft fleet. Trust Vectors define trust and distrust between agents based on three components; current and historical data, intrinsic knowledge of …
Implementation And Optimization Of The Advanced Encryption Standard Algorithm On An 8-Bit Field Programmable Gate Array Hardware Platform, Ryan J. Silva
Theses and Dissertations
The contribution of this research is three-fold. The first is a method of converting the area occupied by a circuit implemented on a Field Programmable Gate Array (FPGA) to an equivalent as a measure of total gate count. This allows direct comparison between two FPGA implementations independent of the manufacturer or chip family. The second contribution improves the performance of the Advanced Encryption Standard (AES) on an 8-bit computing platform. This research develops an AES design that occupies less than three quarters of the area reported by the smallest design in current literature as well as significantly increases area efficiency. …
Professionalism In The Air Force: A Comparative Analysis Of Commissioned Officers With Non-Commissioned Officers, Edward K. Boyd
Professionalism In The Air Force: A Comparative Analysis Of Commissioned Officers With Non-Commissioned Officers, Edward K. Boyd
Theses and Dissertations
Decades ago, military sociologists predicted a rising trend among officers away from traditional institutional military values and toward more economically-based occupational values due to the effects of the transition from a conscription-based military to an all-volunteer force. Subsequent empirical research resulted in data that supports such predictions. More recent researchers have suggested that in addition to the all-volunteer force, an increase on technology may also accelerate the trend toward occupationalism and away from traditional institutional military values and the warrior ethos that typically define successful military organizations. The officer corps may be particularly vulnerable to occupationalism due to increased technical …
Beyond Passswords: Usage And Policy Transformation, Alan S. Alsop
Beyond Passswords: Usage And Policy Transformation, Alan S. Alsop
Theses and Dissertations
The purpose of this research is to determine whether the transition to a two-factor authentication system is more secure than a system that relied only on what users “know” for authentication. While we found that factors that made passwords inherently vulnerable did not transfer to the PIN portion of a two-factor authentication system, we did find significant problems relating to usability, worker productivity, and the loss and theft of smart cards. The new authentication method has disrupted our ability to stay connected to ongoing mission issues, forced some installations to cut off remote access for their users and in one …
Hardware Virtualization Applied To Rootkit Defense, Douglas P. Medley
Hardware Virtualization Applied To Rootkit Defense, Douglas P. Medley
Theses and Dissertations
This research effort examines the idea of applying virtualization hardware to enhance operating system security against rootkits. Rootkits are sets of tools used to hide code and/or functionality from the user and operating system. Rootkits can accomplish this feat through using access to one part of an operating system to change another part that resides at the same privilege level. Hardware assisted virtualization (HAV) provides an opportunity to defeat this tactic through the introduction of a new operating mode. Created to aid operating system virtualization, HAV provides hardware support for managing and saving multiple states of the processor. This hardware …
Development Of An H-Alpha Index For The Detection Of Pms Candidates In Young Open Clusters, Liberty Rae Evanko
Development Of An H-Alpha Index For The Detection Of Pms Candidates In Young Open Clusters, Liberty Rae Evanko
Theses and Dissertations
One phase of formation of medium- and low-mass stars is the optically visible phase known as the pre-main-sequence or PMS phase. In order to further the understanding of this phase, more of these PMS objects need to be identified and classified. Previous techniques have used photometry to identify possible PMS objects by their characteristic Hα emission. Once identified these objects can be studied spectroscopically yielding complete PMS classification. This study develops a method to locate these emission objects that overcomes two limitations of previous techniques. The first limitation is the need for the creation of reddening maps. It is eliminated …
Observational Studies Of Software Engineering Using Data From Software Repositories, Daniel Pierce Delorey
Observational Studies Of Software Engineering Using Data From Software Repositories, Daniel Pierce Delorey
Theses and Dissertations
Data for empirical studies of software engineering can be difficult to obtain. Extrapolations from small controlled experiments to large development environments are tenuous and observation tends to change the behavior of the subjects. In this thesis we propose the use of data gathered from software repositories in observational studies of software engineering. We present tools we have developed to extract data from CVS repositories and the SourceForge Research Archive. We use these tools to gather data from 9,999 Open Source projects. By analyzing these data we are able to provide insights into the structure of Open Source projects. For example, …
Thermally Activated, Variable Blazed Grating For Coherent Beam Steering, Matthew T. Johnson
Thermally Activated, Variable Blazed Grating For Coherent Beam Steering, Matthew T. Johnson
Theses and Dissertations
The ability to perform non-mechanical optical beam steering is of critical importance in laser communication and remote sensing; it is as vital as a phased-array antenna is for RADAR. Directed energy transmission and direction-selective reception increase performance and produce tactical advantage in DoD applications. However, specific geometric features of non-mechanical beam steering devices must be designed in proportion to the wavelength of the monochromatic light to be steered. Also, the ability to handle higher energies by reducing the energy per unit requires large areas of uniform properties on the micrometer scale. These challenges have been addressed in the past using …
Assessment Of Optical Turbulence Profiles Derived From Probabilistic Climatology, Brett W. Wisdom
Assessment Of Optical Turbulence Profiles Derived From Probabilistic Climatology, Brett W. Wisdom
Theses and Dissertations
This research effort assesses the performance of the High Energy Laser End-to-End Operational Simulation (HELEEOS) Climatological C2n optical turbulence model. Path-integrated C2n values of two HELEEOS optical turbulence pro les at 3 distinct operational altitudes are compared to values determined from measured thermosonde data. HELEEOS desert and mid-latitude sites are selected from the Extreme and Percentile Environmental Reference Tables (ExPERT) database for comparison to the thermosonde data. Statistical equivalence of the two datasets is determined through a Design of Experiments (DOE) factorial test to within 80% confidence. The HELEEOS profiles are shown to be equivalent to …