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Predicting Group Performance Using Cohesion And Social Network Density: A Comparative Analysis, Frederick W. Peterson
Predicting Group Performance Using Cohesion And Social Network Density: A Comparative Analysis, Frederick W. Peterson
Theses and Dissertations
Group performance has been an important topic as evidenced by an extensive literature review that has supports a positive relationship between group cohesion and performance. Social network researchers have also found similar relationships between cohesion and group performance using social network density as a proxy for cohesion. The traditional cohesion construct is measured using an attitudinal instrument that relies on member perceptions that are aggregated at the group level. The density construct, on the other hand, is based on social network relations which are based on behaviors and actual member interactions and relationships. Considering these differences, although both cohesion measures …
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 …
Point Spread Function Characterization Of A Radially Displaced Scatterer Using Circular Synthetic Aperture Radar, Uttam K. Majumder
Point Spread Function Characterization Of A Radially Displaced Scatterer Using Circular Synthetic Aperture Radar, Uttam K. Majumder
Theses and Dissertations
This research effort investigated characterizing the point spread function (PSF) behavior of radially displaced point scatterers using circular synthetic aperture radar (CSAR). Thus far, research has been conducted to understand PSF of a scatterer located at the imaging scene center. An analytic closed-form solution has been derived assuming the scatterer is located at the origin of the CSAR imaging geometry. However, it is difficult to derive an analytic PSF solution for a scatterer that is radially displaced from the imaging scene center. Using the back projection image formation algorithm, PSF responses are generated at various point target locations. Consistent with …
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 …
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 …
Phase Diversity And Polarization Augmented Techniques For Active Imaging, Peter M. Johnson
Phase Diversity And Polarization Augmented Techniques For Active Imaging, Peter M. Johnson
Theses and Dissertations
A multi-frame active phase diversity imaging (APDI) algorithm is derived for coherent light statistics and demonstrated. In addition to conventional focal-plane and diversity-plane data, a statistical description for pupil-plane (PP) intensity is formed and included in the derivation. The algorithm is implemented and characterized via Monte Carlo simulation. Analysis shows that it's robust, insensitive to detection noise for SNR ? 7, performs well for SNR's as low as 2, and that the effect of system configuration on optimal parameters is minimal. Furthermore, introduction of PP data results in a 60% better reconstruction from dynamically aberrated data than obtained using only …
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 …
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 …
Cost Growth In Weapons Systems: Re-Examining Rubber Baselines And Ecomonic Factors, Philip E. Ruter Ii
Cost Growth In Weapons Systems: Re-Examining Rubber Baselines And Ecomonic Factors, Philip E. Ruter Ii
Theses and Dissertations
This paper will evaluate cost overruns from a microeconomic perspective to determine their root causes. The specific variables that will be evaluated are: contract budget fluctuations, contract length, inflation, procurement budget fluctuation, research and development budget fluctuation, the technology readiness of the commodity, and industry concentration. These variables will be evaluated twice. The first evaluation will consist of a binary choice model to determine whether or not the dependent variables influence the likelihood of a cost overrun. The specific form of the evaluation will take the form of a probit regression in which an independent variable value of zero indicates …
Optimal Sensor Threshold Control And The Weapon Operating Characteristic For Autonomous Search And Attack Munitions, Roland A. Rosario
Optimal Sensor Threshold Control And The Weapon Operating Characteristic For Autonomous Search And Attack Munitions, Roland A. Rosario
Theses and Dissertations
This Thesis considers the optimal employment of a wide area search munition in a battlespace where a target is known to be uniformly distributed among false targets which are Poisson distributed. The Poisson distribution's parameter is obtained from readily available battlespace intelligence. This work formulates and solves the optimal control problem for deriving the optimal sensor threshold schedule in order to maximize the probability of attacking the target during the battlespace sweep while constraining the probability of attacking a false target. The efficiency gained by optimally varying the sensor threshold is compared against the performance achieved with a static, optimum …
A Modular Mixed Signal Vlsi Design Approach For Digital Radar Applications, Brian M. Brakus
A Modular Mixed Signal Vlsi Design Approach For Digital Radar Applications, Brian M. Brakus
Theses and Dissertations
This study explores the idea of building a library of VHDL configurable components for use in digital radar applications. Configurable components allows a designer to choose which components he or she needs and configures those components for a specific application. By doing this, design time for ASICs and FPGAs is shortened because the components are already designed and tested. This idea is demonstrated with a configurable dynamic pipelinable fast fourier transform. Many FFT implementations exist, but this implementation is both configurable and dynamic. Pre-synthesis customization allows the FFT to be tailored to almost any DSP application, and the dynamic property …
Price Vs. Performance: The Value Of Next Generation Fighter Aircraft, John M. Stelly
Price Vs. Performance: The Value Of Next Generation Fighter Aircraft, John M. Stelly
Theses and Dissertations
The United States Department of Defense (DoD) is currently recapitalizing its aging fighter aircraft inventory with the F-22A and F-35. While the DoD may consider cost and performance issues, it does not use a quantitative model that effectively measures the tradeoffs between the two. This thesis constructs a hedonic model of the fighter aircraft market to measure the implicit price on fighter performance characteristics and specifically applies it to next-generation aircraft. Data from 50 aircraft from 1949-present were used to construct two models – one based on procurement costs and one based on research, design, test, and evaluation (RDT&E) costs. …
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 …
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 …
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 …
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 …
Characterizationn Of Polumer-Based Mems Pyroelectic Infrared Detector, Mark E. Allard
Characterizationn Of Polumer-Based Mems Pyroelectic Infrared Detector, Mark E. Allard
Theses and Dissertations
AFRL/MLPJE had developed a novel thermal sensing material termed protein-impregnated-polymer (PIP). Thus far, a proof-of-concept has been demonstrated using a macro-sized pixel (0.64 mm2) as a bolometric detector. In an effort to better characterize this novel thermal sensing material, experimental data was used to determine figures of merit (FOMs) comparative to off-the-shelf thermal detectors. Microelectromechanical (MEMS) pixels were designed and used as the support structure for an inkjet-deposited droplet of the PIP. During the material characterization, two observations were made: PIP is a pyroelectric material, and the polymer (polyvinyl alcohol (PVA)) without the protein was found to be …
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 …
Multi-Dimensional Classification Algorithm For Automatic Modulation Recognition, Ouail Albairat
Multi-Dimensional Classification Algorithm For Automatic Modulation Recognition, Ouail Albairat
Theses and Dissertations
This thesis proposes an approach for modulation classification using existing features in a more efficient way. The Multi-Dimensional Classification Algorithm (MDCA) treats features extracted from signals of interest as elements with irrelevant identities, hence eliminating any dependence of the classifier on any particular feature. This design enables the use of any number of features, and the MDCA algorithm provides the capability to classify modulations in higher dimensions. The use of multiple features requires an equal number of data dimensions, and thus classification in as high a dimensional space as possible can improve final classification results. Finally, the MDCA algorithm uses …
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. …
Characterization Of Intercalated Graphite Fibers For Microelectromechanical Systems (Mems) Applications, Bryan W. Winningham
Characterization Of Intercalated Graphite Fibers For Microelectromechanical Systems (Mems) Applications, Bryan W. Winningham
Theses and Dissertations
Research was accomplished to characterize the electrical and physical characteristic changes of the Thornel® P-100 carbon fiber and five variants when intercalated with 96% sulfuric acid and incorporated the use of Microelectromechanical Systems (MEMS) structures for testing purposes. The five fiber variants were oxidized in 1 M nitric acid at 0.5 A for 30 seconds, 1 and 2 minutes, the last two samples were detreated at 1150 °C for one hour prior to the nitric acid treatment. The fibers were mounted onto a MEMS die, placed into a chip carrier, sulfuric acid added, the chip carrier sealed and testing accomplished. …
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 …
Direct Diode Pumped Raman Amplifier Based On A Multimode Graded Index Fiberr, Charles James Baird
Direct Diode Pumped Raman Amplifier Based On A Multimode Graded Index Fiberr, Charles James Baird
Theses and Dissertations
The direct pumping of a Raman fiber amplifier (RFA) was attempted using an array of four 25W, fiber pigtailed diodes at 936nm, combined via a 7 channel fiber beam combiner. The initial attempt was conducted using a 1.8 km, 100 micron core, GRIN fiber with an NA of .29 and attenuation 3.6 dB/km at 936nm. While amplification was not achieved, over 200mW of conversion was shown, with 10.4W of pump power and 3.5W of seed. This corresponds to an average conversion efficiency of 2.2%. The subsequent effort utilized a 2km long, 200 micron core, GRIN fiber, with NA of .27 …
Locating Encrypted Data Hidden Among Non-Encrypted Data Using Statistical Tools, Walter J. Hayden
Locating Encrypted Data Hidden Among Non-Encrypted Data Using Statistical Tools, Walter J. Hayden
Theses and Dissertations
This research tests the security of software protection techniques that use encryption to protect code segments containing critical algorithm implementation to prevent reverse engineering. Using the National Institute of Standards and Technology (NIST) Tests for Randomness encrypted regions hidden among non-encrypted bits of a binary executable file are located. The location of ciphertext from four encryption algorithms (AES, DES, RSA, and TEA) and three block sizes (10, 100, and 500 32-bit words) were tested during the development of the techniques described in this research. The test files were generated from the Win32 binary executable file of Adobe's Acrobat Reader version …
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 …
Multi-Dimensional Range Querying Using A Modification Of The Skip Graph, Gregory J. Brault
Multi-Dimensional Range Querying Using A Modification Of The Skip Graph, Gregory J. Brault
Theses and Dissertations
Skip graphs are an application layer-based distributed routing data structure that can be used in a sensor network to facilitate user queries of data collected by the sensor nodes. This research investigates the impact of a proposed modification to the skip graph proposed by Aspnes and Shah. Nodes contained in a standard skip graph are sorted by their key value into successively smaller groups based on random membership vectors computed locally at each node. The proposed modification inverts the node key and membership vector roles, where group membership is computed deterministically and node keys are computed randomly. Both skip graph …
Material Characterization Improvement In High Temperature Rectangle Waveguide Measurements, Eric A. Buschelman
Material Characterization Improvement In High Temperature Rectangle Waveguide Measurements, Eric A. Buschelman
Theses and Dissertations
This research presents a method by which electromagnetic characterization of materials in a partially filled waveguide can be accurately performed. Higher order modes are excited by the geometry, which are not accounted for in most algorithms. A correction must consider the power transmitted by higher-order modes. Modal solutions, using reference plane independence, for a single top air gap between the material sample and the waveguide wall, are also presented. Characterization is performed on samples of acrylic and rubberized magnetic radar absorbing material. Calculation of the complex permittivity and permeability of shielding material, within 10% of the true value, was achieved …
Sub-Surface Navigation Using Very-Low Frequency Electromagnetic Waves, Alan L. Harner
Sub-Surface Navigation Using Very-Low Frequency Electromagnetic Waves, Alan L. Harner
Theses and Dissertations
This research proposes two schemes utilizing very-low frequency (VLF) electromagnetic waves to navigate underground. The first scheme consists of using above-ground beacon transmitters to broadcast VLF signals to an underground mobile receiver which uses methods such as triangulation and trilateration to obtain a position solution. The second scheme consists of using above-ground reference receivers along with an underground mobile receiver to form time-difference- of-arrival measurements of incoming VLF signals of opportunity, such as lightning strike emissions, to calculate a position solution. The objective of this thesis is to develop positioning algorithms and use simulations as a tool to characterize the …
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 …