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2005

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Articles 1681 - 1710 of 3074

Full-Text Articles in Engineering

Noise Estimation In The Presence Of Bpsk Digital Burst Transmissions, Susan E. Bettison Mar 2005

Noise Estimation In The Presence Of Bpsk Digital Burst Transmissions, Susan E. Bettison

Theses and Dissertations

This research explores noise estimation techniques in an attempt to improve upon a previously developed digital burst transmission Binary Phase Shift Keyed (BPSK) demodulator. The demodulator success is dependent on the accuracy of the estimate of Power Spectral Density (PSD) of the unknown noise. Given a discrete time signal transformed into the frequency domain, the research seeks to determine if it is possible to effectively estimate the PSD of the unknown noise. The demodulator was developed using a new signal model for digital burst transmissions based on linear spectral subspace theory. Using this model and the redundancy properties of BPSK …

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Executable Architectures And Their Application To A Geographically Distributed Air Operations Center, Robert J. Beal, Jeremy P. Hendrix, Garth P. Mcmurray, William C. Stewart Mar 2005

Executable Architectures And Their Application To A Geographically Distributed Air Operations Center, Robert J. Beal, Jeremy P. Hendrix, Garth P. Mcmurray, William C. Stewart

Theses and Dissertations

Integrated Architectures and Network Centric Warfare represent two central concepts in the Department of Defense's (DoD) on-going transformation. The true power of integrated architectures is brought to bear when they are combined with simulation to move beyond a static representation and create an executable architecture. This architecture can then be used to experiment with system configurations and parameter values to guide employment decisions. The process of developing and utilizing an executable architecture will be employed to assess an Air Operations Center (AOC). This thesis applies and expands upon the methodology of Dr. Alexander Levis, former Chief Scientist of the Air …

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Thermal Characteristics Of Pitch Based Carbon Foam And Phase Change Materials, Kevin W. Wierschke Mar 2005

Thermal Characteristics Of Pitch Based Carbon Foam And Phase Change Materials, Kevin W. Wierschke

Theses and Dissertations

Phase-change thermal energy storage devices offer thermal control systems an option that allows a smaller heat sink to be used by absorbing the thermal energy quickly and storing it in the phase change to prevent failure of electronic components and then slowly releasing the heat to the heat sink. This paper experimentally determined the transient response of carbon foam with a phase-change material by measuring the response to a step temperature input to test samples. The transient response was recorded until steady state was reached. An analytic response was created and compared against the measured response. A simplified analytic prediction …

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Technical Feasibility Of Loitering Lighter-Than-Air-Near-Space Maneuvering Vehicles, Eric R. Moomey Mar 2005

Technical Feasibility Of Loitering Lighter-Than-Air-Near-Space Maneuvering Vehicles, Eric R. Moomey

Theses and Dissertations

The near-space region of earth's atmosphere above 20 kilometers altitude is greatly underutilized. Lighter-than-air maneuvering vehicles, or airships, using the principle of buoyancy can take advantage of this region to become potential platforms for precision navigation, environmental monitoring, communication relays, missile warning, surveillance, and weapon delivery. These vehicles purportedly provide persistent coverage over large areas of the earth's surface at substantially lower costs than orbiting satellites. This study investigated the technical requirements to loiter an operational payload within this high altitude region using a lighter-than-air maneuvering platform. A parametric analysis was conducted to identify the critical technologies needed to achieve …

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A Comparison Of Hazard Predication And Assessment Capability (Hpac) Software Dose-Rate Contour Plots To A Sample Of Local Fallout Data From Test Detonations In The Continental United States, 1945-1962, Richard W. Chancellor Mar 2005

A Comparison Of Hazard Predication And Assessment Capability (Hpac) Software Dose-Rate Contour Plots To A Sample Of Local Fallout Data From Test Detonations In The Continental United States, 1945-1962, Richard W. Chancellor

Theses and Dissertations

A comparison of Hazard Prediction and Assessment Capability (HPAC) software dose-rate contour plots to a sample of local nuclear fallout data from test detonations in the continental United States, 1945 - 1962, is performed. Fallout data from test detonations is obtained from "Compilation of Local Fallout Data from Test Detonations 1945- 1962 Extracted from DASA 1251, Volume I - Continental U.S. Tests." This report contains fallout plots and radiation contours for each test in the atmospheric nuclear test program conducted by the United States prior to 1963. These plots are compared with the plots resulting from Defense Threat Reduction Agency's …

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Surface Oxidation Study Of Uranium Dioxide Under Wet And Dry Conditions, Gary T. Brett Mar 2005

Surface Oxidation Study Of Uranium Dioxide Under Wet And Dry Conditions, Gary T. Brett

Theses and Dissertations

The surface oxidation of pressed uranium dioxide (UO2) powder under controlled environmental conditions and the oxidation and reduction of pressed uranium trioxide (UO3) powder are presented. This is a continuing research project in the investigation of the oxidation of UO2 powder using Photoluminescence (PL) Spectroscopy. UO2 particles exposed to the ambient atmosphere will oxidize into a number of chemical complexes (specifically hydrates, hydroxides, and carbonates). During certain of these oxidation processes, the uranium ion can lose two of its electrons and change from uranous (UIV+) to uranyl (UVI+). This research …

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Air Force Jp-8 Fuel Distribution System: A Statistical Analysis To Determine Where And When To Sample, Eric J. Heath Mar 2005

Air Force Jp-8 Fuel Distribution System: A Statistical Analysis To Determine Where And When To Sample, Eric J. Heath

Theses and Dissertations

The Air Force Petroleum Office at Wright-Patterson Air Force Base, Ohio collects JP-8 sampling data, but this data doesn't undergo analysis to determine the health of the base-level JP-8 fuel distribution system. Commanders possess no known confidence level when assessing base-level fuel health. Therefore, the objective of this research is to assess Air Force base-level fuel sampling data to determine the base-level sampling point that ensures a quality and healthy product at the aircraft. Also, this research seeks to identify how often correlation sampling should take place. Sample test pass rates are analyzed from three locations, receipt, storage, and vehicles/aircraft, …

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Minimizing Security Forces Response Times Through The Use Of Facility Location Methodologies, Michael C. Dawson Mar 2005

Minimizing Security Forces Response Times Through The Use Of Facility Location Methodologies, Michael C. Dawson

Theses and Dissertations

Since the events of September 11, 2001, security for the nation's Intercontinental Ballistic Missile force has become a prominent concern for personnel in the highest levels of government. This has resulted in many physical security upgrades and new methods to counter hostile activities. This research seeks to find the optimal placement for one layer of the security net protecting these crucial assets, the daily-deployed security forces Fire Teams. The problem of finding the optimal placement for these forces is modeled as a facility location problem. Three of the methods of locating facilities available in the literature are selected to solve …

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A Multiple-Case Analysis Of Lean Six Sigma Deployment And Implementation Strategies, Peter M. O'Rourke Mar 2005

A Multiple-Case Analysis Of Lean Six Sigma Deployment And Implementation Strategies, Peter M. O'Rourke

Theses and Dissertations

Lean and Six Sigma are recent developments in continuous improvement methodology that have been popularized by several high-profile companies. The success and complementary nature of these methodologies has led to their combination into a single methodology, commonly called Lean Six Sigma or Lean Sigma. Although there is considerable literature available and many consultants involved with Lean Six Sigma, very little published research addresses the practical experiences of companies that have implemented Lean Six Sigma. The research question for this research is: How and why are certain private sector implementations of Lean Six Sigma successful or unsuccessful? The investigative questions further …

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Analysis Of Online-Delaunay Navigation For Time Sensitive Targeting, David Chow Mar 2005

Analysis Of Online-Delaunay Navigation For Time Sensitive Targeting, David Chow

Theses and Dissertations

Given the drawbacks of leaving time-sensitive targeting (TST) strictly to humans, there is value to the investigation of alternative approaches to TST operations that employ autonomous systems. This paper accomplishes five things. First, it proposes a short-hop abbreviated routing paradigm (SHARP) - based on Delaunay triangulations (DT), ad-hoc communication, and autonomous control - for recognizing and engaging TSTs that, in theory, will improve upon persistence, the volume of influence, autonomy, range, and situational awareness. Second, it analyzes the minimum timeframe need by a strike (weapons enabled) aircraft to navigate to the location of a TST under SHARP. Third, it shows …

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Feasibility Study Of Variance Reduction In The Thunder Campaign-Level Model, Earl M. Bednar Mar 2005

Feasibility Study Of Variance Reduction In The Thunder Campaign-Level Model, Earl M. Bednar

Theses and Dissertations

As an Air Force Chief of Staff endorsed topic, Air Force Studies and Analyses Agency (AFSAA) requested an effective and efficient way to reduce the variance in analysis results from THUNDER. THUNDER is a large-scale discrete event simulation of campaign-level military operations and is used to examine issues involving the utility and effectiveness of air and space power in a theater-level, joint warfare context. Given the large number of stochastic components within THUNDER, results are produced with highly variable measures of effectiveness (MOEs), causing difficulties in evaluating alternative force structures, weapon systems, etc. This work responds to AFSAA's request by …

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Optimal Maintenance For Stochastically Degrading Satellite Constellations, Timothy J. Cook Mar 2005

Optimal Maintenance For Stochastically Degrading Satellite Constellations, Timothy J. Cook

Theses and Dissertations

This thesis develops a methodology to determine an optimal policy for maintaining a satellite constellation that degrades over time. Previous work has developed a methodology to compute an optimal replacement policy for a satellite constellation in which satellites were viewed as binary entities, either operational or failed. This research extends the previous models by developing an optimal maintenance policy for satellite constellations in which each satellite may operate in a finite number of degraded states. The constellation is assumed to consist of a finite number of satellites, each with a finite number of functions with distinct failure mechanisms. Assuming each …

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A Knowledge Matrix Modeling Of The Intelligence Cycle, Kevin J. Whaley Mar 2005

A Knowledge Matrix Modeling Of The Intelligence Cycle, Kevin J. Whaley

Theses and Dissertations

This effort models information flow through the United States Intelligence Community's Intelligence Cycle using a knowledge matrix methodology. The knowledge matrix methodology takes explicit data from multiple sources and fuses that data to measure a current level of knowledge about a target, or situation. Knowledge matrices are used to develop a measure of user-needs satisfaction. User-needs satisfaction compares requested levels of knowledge to a probability of collecting that knowledge within a designated timeframe. This effort expands the work done by Captain Carl Pawling in his March 2004 thesis, Modeling and Simulation of the Military Intelligence Process, by modeling intelligence as …

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On The Use Of Surrogate Functions For Mixed Variable Optimization Of Simulated Systems, John E. Dunlap Mar 2005

On The Use Of Surrogate Functions For Mixed Variable Optimization Of Simulated Systems, John E. Dunlap

Theses and Dissertations

This research considers the efficient numerical solution of linearly constrained mixed variable programming (MVP) problems, in which the objective function is a black-box stochastic simulation, function evaluations may be computationally expensive, and derivative information is typically not available. MVP problems are those with a mixture of continuous, integer, and categorical variables, the latter of which may take on values only from a predefined list and may even be non-numeric. Mixed Variable Generalized Pattern Search with Ranking and Selection (MGPS-RS) is the only existing, provably convergent algorithm that can be applied to this class of problems. Present in this algorithm is …

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Usable Design Of Civil Engineer Information Systems, Gunther Kastenholz Mar 2005

Usable Design Of Civil Engineer Information Systems, Gunther Kastenholz

Theses and Dissertations

This research used a case study methodology where one instrument used to collect data was a heuristic usability inspection method. Data was collected from a literature review of pertinent Civil Engineer information system design documents, and conclusions drawn about the existing level of specification of usability engineering principles. The heuristic usability inspection method was used to validate the conclusions drawn through inspection of an information system representative of other Civil Engineer information systems, the Automated Civil Engineer System Personnel Readiness module.

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Modeling And Analysis Of Clandestine Networks, Clinton R. Clark Mar 2005

Modeling And Analysis Of Clandestine Networks, Clinton R. Clark

Theses and Dissertations

Since Sept. 11, 2001, there has been great interest in the military and intelligence communities in using Social Network Analysis (SNA) to support the disruption and destruction of global terrorist networks. SNA results, however, tend to be descriptive and are limited due to the lack of advantageous properties of the relationship measures applied to the arcs in a social network. Further, SNA techniques generally focus on a single network context while real relationships are based in multiple contexts. This thesis develops a new proxy measure of pair-wise potential influence between members of a network, a Holistic Interpersonal Influence Measure (HIIM). …

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Estimating Performance Time For Air Force Military Construction Projects, Greg J. Hoffman Mar 2005

Estimating Performance Time For Air Force Military Construction Projects, Greg J. Hoffman

Theses and Dissertations

The prediction of construction time performance is a problem of interest to both researchers and construction industry practitioners. This research seeks to identify significant factors which may influence construction durations for Air Force Military Construction (MILCON) projects to establish a time prediction model. Data were collected for 856 MILCON projects completed between 1988 and 2004; this included both traditional facility and non-facility (e.g. airfield pavements, utilities) projects. These data were analyzed using Bromilow's time-cost (BTC) model (1969) as well as multiple linear regression. Neither model produced acceptable results for non-facility projects; however, the multiple linear regression model was found to …

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An Evaluation Of Contingency Construction Methods Using Value Focused Thinking, John E. Tyron Mar 2005

An Evaluation Of Contingency Construction Methods Using Value Focused Thinking, John E. Tyron

Theses and Dissertations

Rapid Engineering Deployable, Heavy Operational Repair Squadron, Engineer (RED HORSE) Squadrons are 400-person, self-contained, combat engineer units that provide deployable and flexible expert construction capability for the United States Air Force. To help meet Air Force mission requirements, RED HORSE units currently employ a variety of traditional and innovative construction methods. But their alternatives-focused decision analysis approach to method selection limits their decision to known alternatives and may not fully achieve all of their objectives. This research developed a generic value-focused thinking (VFT) decision analysis model to help RED HORSE evaluate and select contingency construction methods. Eight alternatives were generated …

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Decision Analysis Using Value-Focused Thinking To Select Renewable Alternative Fuels, Eric A. Queddeng Mar 2005

Decision Analysis Using Value-Focused Thinking To Select Renewable Alternative Fuels, Eric A. Queddeng

Theses and Dissertations

The United States relies on imported oil as a result of domestic petroleum consumption rates greatly exceeding production rates. Alternative fuels are a major force in the effort to reduce petroleum consumption in the transportation industry. The transportation industry also accounts for 1/3 of all greenhouse gas emissions and nearly half of all cancers attributed to outdoor sources of pollutants. The purpose of this research was to evaluate the economic and environmental feasibility of renewable alternative fuels and associated blends (ethanol, methanol, 100% biodiesel (B100), 20% biodiesel (B20) and e-diesel) compared to non-renewable alternative fuels (compressed natural gas and propane) …

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Information Technology Implementation And Sustainment Model: Data Collection Instrument, Walter K. Yazzie Mar 2005

Information Technology Implementation And Sustainment Model: Data Collection Instrument, Walter K. Yazzie

Theses and Dissertations

The goal of this research was to develop a data collection instrument for an existing information technology implementation and sustainment model. In 2003, a unique system dynamics model was developed at the Air Force Institute of Technology to predict the behavior of information technology implementation and sustainment (Fonnesbeck, 2003). However, no empirical data was used during the model development. In order to collect the needed empirical data, this research develops a data collection instrument for the model. The instrument was sent to 60 Air Force community planners who are currently implementing a geographical information system (Air Force GeoBase) into their …

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Modeling Application Of Hydrogen Release Compound To Effect In Situ Bioremediation Of Chlorinated Solvent-Contaminated Groundwater, Ryan C. Wood Mar 2005

Modeling Application Of Hydrogen Release Compound To Effect In Situ Bioremediation Of Chlorinated Solvent-Contaminated Groundwater, Ryan C. Wood

Theses and Dissertations

This study investigates how application of Hydrogen Release Compound (HRC) might be implemented to remediate a site contaminated with tetrachloroethene (PCE) or its daughter products, under varying site conditions. The 3-D reactive transport model RT3D was coupled with a dual-Monod biodegradation submodel to simulate the effect of the hydrogen generated by HRC on accelerating the biodegradation of dissolved chlorinated solvents. Varying site conditions and injection well configurations were investigated to determine the effect of these environmental and design conditions on overall treatment efficiency. The model was applied to data obtained at a chlorinated solvent contaminated site at Vandenberg AFB, where …

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An Investigation Of Geobase Mission Data Set Design, Implementation, And Usage Within Air Force Civil Engineer Electrical And Utilities Work Centers, Paul C. Loeber Mar 2005

An Investigation Of Geobase Mission Data Set Design, Implementation, And Usage Within Air Force Civil Engineer Electrical And Utilities Work Centers, Paul C. Loeber

Theses and Dissertations

In 2001, the Office of the Civil Engineer, Installation and Logistics, Headquarters, United States Air Force, (ILE) identified Civil Engineer Squadrons as the central point of contact for all base-level mapping requirements/activities. In order to update mapping methods and procedures, ILE has put into place a program called GeoBase, which uses private sector Geographic Information Systems (GIS) technology as a foundation. In its current state, GeoBase uses the concept of a "Common Installation Picture (CIP)" to describe the goal of a consolidated "visual" that integrates the many layers of mapping information. The CIP visual is formed from a collection of …

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An Historical Analysis Of Factors Contributing To The Emergence Of The Intrusion Detection Discipline And Its Role In Information Assurance, James L.M. Hart Mar 2005

An Historical Analysis Of Factors Contributing To The Emergence Of The Intrusion Detection Discipline And Its Role In Information Assurance, James L.M. Hart

Theses and Dissertations

In 2003, Gartner, Inc., predicted the inevitable demise of the intrusion detection (ID) market, a major player in the computer security technology industry. In light of this prediction, IT executives need to know if intrusion detection technologies serve a strategic purpose within the framework of information assurance (IA). This research investigated the historical background and circumstances that led to the birth of the intrusion detection field and explored the evolution of the discipline through current research in order to identify appropriate roles for IDS technology within an information assurance framework. The research identified factors contributing to the birth of ID …

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An Analysis Of Information Assurance Relating To The Department Of Defense Radio Frequency Identification (Rfid) Passive Network, Robert G. Giovannetti Mar 2005

An Analysis Of Information Assurance Relating To The Department Of Defense Radio Frequency Identification (Rfid) Passive Network, Robert G. Giovannetti

Theses and Dissertations

The mandates for suppliers to commence Radio Frequency Identification tagging set by Wal-Mart and the Department of Defense is changing this long-time rumored technology into reality. Despite the many conveniences to automate and improve asset tracking this technology offers, consumer groups have obstinately opposed this adoption due to the perceived weaknesses in security and privacy of the network. While the heated debate between consumers and retailers continues, little to no research has addressed the implications of security on the Department of Defense Radio Frequency Identification network. This thesis utilized a historical analysis of Radio Frequency Identification literature to determine whether …

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Investigation Of Aerobraking To Return The Space Maneuver Vehicle To Low Earth Orbit From Geotransfer Orbit, Benjamin M. Berlin Mar 2005

Investigation Of Aerobraking To Return The Space Maneuver Vehicle To Low Earth Orbit From Geotransfer Orbit, Benjamin M. Berlin

Theses and Dissertations

This study investigated the use of ballistic and Double-Dip'' aerobraking reentry to return the Space Maneuver Vehicle (SMV) from geotransfer orbit in no more than two atmosphere passes. Lift and drag accelerations were applied to the two-body problem when either of their magnitudes exceeded 1/1000 g. Lift and drag coefficients, along with the SMV model, were taken from Investigation of Atmospheric Reentry for the Space Maneuver Vehicle by Captain McNabb, AFIT/GA/ENY/04-M03. Target perigees were formulated using the two-body problem. The orbit from each target perigee was numerically integrated around a planar earth model using a fourth order Runge-Kutta method. Ballistic …

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Effectively Managing The Air Force Enterprise Architecture, Jamie P. Sharkey Mar 2005

Effectively Managing The Air Force Enterprise Architecture, Jamie P. Sharkey

Theses and Dissertations

The Air Force is developing and implementing an enterprise architecture to meet the Clinger-Cohen Act's requirement that all federal agencies use an architecture to guide their information technology (IT) investments. However, this act does not provide guidance on how to effectively manage an enterprise architecture. Prior research applied maturity models and competency stages to manage an enterprise architecture by defining layers of enterprise architecture management maturity. However, these efforts tend to view enterprise architecture development as a one-time planning process rather than an iterative progression. Enterprise architecture is not a one-time exercise, but rather it is an on-going effort within …

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Passwords: A Survey On Usage And Policy, Kurt W. Martinson Mar 2005

Passwords: A Survey On Usage And Policy, Kurt W. Martinson

Theses and Dissertations

Computer password use is on the rise. Passwords have become one of the primary authentication methods used today. It is because of their high use that organizations have started to place parameters on passwords. Are password restrictions a nuisance? What are some of the consequences that result as organizations place the burden of their computer security on passwords? This thesis analyzes the results of a survey instrument that was used to determine if individuals are using similar techniques or patterns when choosing or remembering their passwords. It also looks at how individuals feel about using passwords. In addition, the authors …

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The Feasibility Of The U.S. Air Force Mandating The Exclusive Use And Purchase Of Forest Stewardship Council Certified Wood And Paper Containing 100% Post Consumer Content, Silinda Johnson Mar 2005

The Feasibility Of The U.S. Air Force Mandating The Exclusive Use And Purchase Of Forest Stewardship Council Certified Wood And Paper Containing 100% Post Consumer Content, Silinda Johnson

Theses and Dissertations

The Resource Conservation and Recovery Act required federal agencies to purchase products with the highest recovered content (or post-consumer content in the case of paper) as practicable. The Office of Federal Procurement Policy required all executive agencies to give preference in their procurement programs to products that conserve natural resources and protect the environment. These requirements necessitate that the Air Force consider purchasing 100% post-consumer content (PCC) paper and Forest Stewardship Council (FSC) certified wood because of their environmentally preferable attributes. This study compared the availability, performance standards, and prices of 100% PCC paper to 30% PCC paper and FSC-certified …

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Project Portfolio Management: An Investigation Of One Air Force Product Center, Bryan D. Edmunds Mar 2005

Project Portfolio Management: An Investigation Of One Air Force Product Center, Bryan D. Edmunds

Theses and Dissertations

Over the last two decades, reducing product development times in the DoD has been the focus of many committees, commissions, and research efforts. Despite the implementation of numerous recommendations, the DoD still struggles with long acquisition cycle times. This research is part of the Air Force Cycle Time Reduction Research Program (CTRRP), which grew out of the Cycle Time Reduction Action Plan, developed in 1998. This research focuses on the portfolio management (project selection and resource allocation) part of the CTRRP. The purpose of this research effort was to investigate the use of portfolio management within the Air Force. Specifically, …

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Daytime Detection Of Space Objects, Alistair D. Funge Mar 2005

Daytime Detection Of Space Objects, Alistair D. Funge

Theses and Dissertations

Space Situational Awareness (SSA) requires repeated object updates for orbit accuracy. Detection of unknown objects is critical. A daytime model was developed that evaluated sun flares and assessed thermal emissions from space objects. Iridium satellites generate predictable sun glints. These were used as a model baseline for daytime detections. Flares and space object thermal emissions were examined for daytime detection. A variety of geometric, material and atmospheric characteristics affected this daytime detection capability. In a photon noise limited mode, simulated Iridium flares were detected. The peak Signal-to- Noise Ratios (SNR) were 6.05e18, 9.63e5, and 1.65e7 for the nighttime, daytime and …

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