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1996

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Evaluation Of Hazardous Material Life Cycle Cost Tools For Use In Air Force Hazardous Material Pharmacies, Rowene J. Resler Dec 1996

Evaluation Of Hazardous Material Life Cycle Cost Tools For Use In Air Force Hazardous Material Pharmacies, Rowene J. Resler

Theses and Dissertations

This research focuses on evaluation of various tools that assist in the selection of hazardous material substitutes. Substitute material consideration is a function of the Hazardous Material Pharmacy (HMP) when a hazardous material is requested for purchase and use in a current base operation. The substitute material decision is complex, involving identification of potential substitutes and then comparison of factors, such as cost, performance, and environmental effects, between the potential substitute and the material being requested. Various tools such as life cycle cost models, databases, and other information services can provide assistance to HMPs making substitution decisions.

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Evaluation Of Design Tools For Rapid Prototyping Of Parallel Signal Processing Algorithms, James C. Savage Dec 1996

Evaluation Of Design Tools For Rapid Prototyping Of Parallel Signal Processing Algorithms, James C. Savage

Theses and Dissertations

Digital signal processing (DSP) has become a popular method for handling not only signal processing, but communications, and control system applications. A DSP application of interest to the Air Force is high speed avionics processing. The real time computing requirements of avionics processing exceed the capabilities of current single chip DSP processors, and parallelization of multiple DSP processors is a solution to handle such requirements. Designing and implementing a parallel DSP algorithm has been a lengthy process often requiring different design tools and extensive programming experience. Through the use of integrated software development tools, rapid prototyping becomes possible by simulating …

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Weighted Mahalanobis Distance For Hyper-Ellipsoidal Clustering, Khaled S. Younis Dec 1996

Weighted Mahalanobis Distance For Hyper-Ellipsoidal Clustering, Khaled S. Younis

Theses and Dissertations

Cluster analysis is widely used in many applications, ranging from image and speech coding to pattern recognition. A new method that uses the weighted Mahalanobis distance (WMD) via the covariance matrix of the individual clusters as the basis for grouping is presented in this thesis. In this algorithm, the Mahalanobis distance is used as a measure of similarity between the samples in each cluster. This thesis discusses some difficulties associated with using the Mahalanobis distance in clustering. The proposed method provides solutions to these problems. The new algorithm is an approximation to the well-known expectation maximization (EM) procedure used to …

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Performance Analysis Of Preemption Algorithms In An Idnx Circuit Switch Communications Network, Eric C. Gumbs Dec 1996

Performance Analysis Of Preemption Algorithms In An Idnx Circuit Switch Communications Network, Eric C. Gumbs

Theses and Dissertations

Access to communication networks is increasing rapidly. The increase access to these networks results in delays and at times loss of data. At times of peak traffic or when trunks or nodes are down, very important customers' communications requirements are not met. One way to combat this problem is to prioritize the network and provide different levels of grade of service (GOS) for each priority. Call preemption provides an effective method of obtaining different levels of GOS. This research seeks to design the best circuit switch communications network preemption model for the DoD by analyzing previously developed preemption algorithms. Four …

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Interference Suppression For Spread Spectrum Signals Using Adaptive Beamforming And Adaptive Temporal Filter, Wonjin Park Dec 1996

Interference Suppression For Spread Spectrum Signals Using Adaptive Beamforming And Adaptive Temporal Filter, Wonjin Park

Theses and Dissertations

Interference and jamming signals are a serious concern in an operational military communication environment. This thesis examines the utility and performance of combining adaptive temporal filtering with adaptive spatial filtering (i.e. adaptive beamforming) to improve the signal-to-jammer ratio (SJR) in the presence of narrowband and wideband interference. Adaptive temporal filters are used for narrowband interference suppression while adaptive beamforming is used to suppress wideband interference signals. A procedure is presented for the design and implementation of a linear constraints minimum variance generalized sidelobe canceler (LCMV-GSC) beamformer. The adaptive beamformer processes the desired signal with unity gain while simultaneously and adaptively …

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Experimental Investigation Of Radar Cross Section Spatial Correlation Properties For A Point Scattering Target, John D. Shannon Dec 1996

Experimental Investigation Of Radar Cross Section Spatial Correlation Properties For A Point Scattering Target, John D. Shannon

Theses and Dissertations

This research investigates the spatial correlation of RCS. In pulsed radar systems, probability of detection for partially correlated signals depends on the autocovariance of the target's RCS. The RCS changes pulse to pulse due to spatial and time fluctuations. Spatial fluctuation are due to the motion of all scatterers relative to the radar (i.e. changing aspect angle). Time fluctuations are due to relative motion of scatterers to each other (i.e. wings flexing, engines spinning). Theory developed at AFIT [9] can generate autocovariance estimates from a distribution of scatterers. Theory based autocovariance estimates are compared to static measurement based autocovariance estimates …

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Personnel Airdrop Risk Assessment Using Bootstrap Sampling, Wonsik Kim Dec 1996

Personnel Airdrop Risk Assessment Using Bootstrap Sampling, Wonsik Kim

Theses and Dissertations

Previous work on personnel airdrop problems involving jumpers has been (1) event-oriented entanglement rates, (2) number of canopy bumps, (3) landing injuries, and (4) deaths. The thesis expands this area of research by developing cumulative distribution functions of maximum possible chute entanglement risk for the C-17 using bootstrap techniques. By comparing the effects of various C-17 aircraft configurations on the entanglement CDF, this thesis shows that under certain configurations the risk of centerline entanglement for the C-17 is less than for the C-141.

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The Capacity Of The Air Force Satellite Control Network, Kwangho Jang Dec 1996

The Capacity Of The Air Force Satellite Control Network, Kwangho Jang

Theses and Dissertations

The daily mission objective of the Air Force Satellite Control Network (AFSCN) is to support communication with satellite systems. It is critical that the AFSCN operate 24 hours a day, seven days a week. Previous work on the satellite range scheduling problem has successfully scheduled over 90 percent of the satellite support requests. This research investigates the capacity of the AFSCN using an available satellite scheduling algorithm. This research has three objectives. The first objective is to be able to generate sample data sets which represent a day of satellite support requests for low, medium, and high altitude satellites. The …

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Manipulating The Ooda Loop: The Overlooked Role Of Information Resource Management In Information Warfare, Gregory M. Schechtman Dec 1996

Manipulating The Ooda Loop: The Overlooked Role Of Information Resource Management In Information Warfare, Gregory M. Schechtman

Theses and Dissertations

A ground-swell of interest in information as a weapon of warfare is growing within the U.S. armed services. Military strategists are looking at information as a tool to leverage our forces and make them irresistible in battle. Yet, there is little agreement as to what information warfare (IW) is, let alone how it is best fought. This fundamental disagreement is serving as an impediment to unified actions as the Air Force seeks its role in this arena. In particular, information resource management practitioners are questioning their role in supporting this mission. This thesis discusses limitations of existing information warfare interpretations …

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The New Logic Of Hypertext: Electronic Documents, Literary Theory, And Air Force Publications, Gordon G. Geison Dec 1996

The New Logic Of Hypertext: Electronic Documents, Literary Theory, And Air Force Publications, Gordon G. Geison

Theses and Dissertations

Hypertext systems offer electronic links that can instantly join related documents with the click of a mouse. Some observers predict that in the next few years hypertext will become the predominate technology of communication. Such a revolutionary transformation of our culture's basic system for sharing information is bound to have a profound and wide-ranging impact. At this early stage in hypertext's evolutionary development, no empirical study can be expected to capture the long-term implications of this new technology. An exploratory survey was distributed to 100 large corporations to gather their initial assessment of the revolutionary implications of hypertext. The results …

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Air Force Media Use And Conformance With Media Richness Theory: Implications For E-Mail Use And Policy, Heather L. Adams Dec 1996

Air Force Media Use And Conformance With Media Richness Theory: Implications For E-Mail Use And Policy, Heather L. Adams

Theses and Dissertations

Communication has become a major aspect of a manager's job. When communicating, they are faced with many choices of what media to use - some include face-to-face, telephone, e-mail, or written. Managerial effectiveness can improve if managers make appropriate media choices. Thus, it is important to study how Air Force managers perceive media and what kind of choices they are making based on those perceptions. Media Richness Theory suggests that media choices are affected by content reasons, situational reasons, and symbolic reasons. This study examined Air Force managers and found they conform highly with Media Richness Theory in their media …

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Records Analysis And Classification System: A Proof Of Concept System For The Automated Classification Of United States Air Force Records, David W. Snoddy Dec 1996

Records Analysis And Classification System: A Proof Of Concept System For The Automated Classification Of United States Air Force Records, David W. Snoddy

Theses and Dissertations

The records management process utilized within the Department of Defense (DoD) is currently labor intensive. Work is being done to automate portions of this process, but classifying documents and assigning disposition instructions remains a labor intensive, manual operation. Although the requirement for this capability was identified by a DoD sponsored study, an automated computer-based system which can classify and apply disposition instructions has yet to be developed for use within the DoD. This thesis study presents a proof of concept computer program called the Records Analysis and Classification System (RACS) which was developed to demonstrate computer-based techniques for the automated …

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Converting Publications In The Air Force To Sgml: A Recommendation Based On Commercial Experience, Shari T. Miles Dec 1996

Converting Publications In The Air Force To Sgml: A Recommendation Based On Commercial Experience, Shari T. Miles

Theses and Dissertations

The objective of this research was to determine those benefits of SGML that the Air Force can use in its publications process and to determine if benchmarking can improve the Air Force's migration to an electronic publishing environment. To accomplish this, the author completed an exploratory, qualitative study which defined the components and benefits of SGML and the benchmarking application and process. The qualitative techniques for this research included a literature review and questionnaire. The literature review covered both SGML and benchmarking. The questionnaire was an exploratory instrument that was sent to 60 commercial enterprises. The results of the questionnaire …

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Exploring The Policy Issues Of Electronic Freedom Of Information Act Requests Through The Use Of The Government Information Locator Service, Lori A. Rogers Dec 1996

Exploring The Policy Issues Of Electronic Freedom Of Information Act Requests Through The Use Of The Government Information Locator Service, Lori A. Rogers

Theses and Dissertations

This study provides a preliminary view of the policy issues involved with allowing electronic Freedom of Information Act (FOIA) requests through the use of the Government Information Locator Service. The author used an exploratory, qualitative methodology consisting of an extensive literature review and a self-administered questionnaire that was sent to 54 Air Force (AF) FOIA managers. The literature review revealed that an informed citizenry is critical to a democratic society. To ensure its citizens have the opportunity to stay informed, Congress has enacted and amended laws to protect public access to federal information. The primary benefits of electronic FOIA requests …

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Digital Rosetta Stone: A Conceptual Model For Maintaining Long-Term Access To Digital Documents, Steven B. Robertson Dec 1996

Digital Rosetta Stone: A Conceptual Model For Maintaining Long-Term Access To Digital Documents, Steven B. Robertson

Theses and Dissertations

Due to the rapid evolution of technology, future digital systems may not be able to read and/or interpret the digital recordings made by older systems, even if those recordings are still in good condition. This thesis addresses the problem of maintaining long-term access to digital documents and provides a methodology for overcoming access difficulties due to technological obsolescence. A review was conducted to determine the long-term access methods that have already been suggested by other researchers. These previously suggested methods are then combined with other ideas that were encountered and conceived while performing research for this project. The combination of …

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Internet Use Patterns, Acceptance Levels, And Policy Recommendations: An Information Technology Infusion Approach To The Internet And The United States Air Force, Pamela E. Quintero Dec 1996

Internet Use Patterns, Acceptance Levels, And Policy Recommendations: An Information Technology Infusion Approach To The Internet And The United States Air Force, Pamela E. Quintero

Theses and Dissertations

Information technology infusion has taken place in the workplace as costs for microcomputers have declined and the need for reliable and timely information has increased, but the impact the Internet has had is yet to be determined. This research takes an information technology infusion approach to the Internet and focuses on the use patterns of current Air Force Internet users, acceptance levels, and supervisory support of the technology, as well as policy recommendations regarding Internet use in the Air Force. The research provides substantial evidence that Internet technology is not being infused equally within all organizational levels in the Air …

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On-Line Publications: Defining Requirements For User Acceptance, Jefferey T. Hennes Dec 1996

On-Line Publications: Defining Requirements For User Acceptance, Jefferey T. Hennes

Theses and Dissertations

This study investigated user requirements for an on-line system to distribute United States Air Force publications. Requirements were gathered utilizing focus groups of users from the students and staff of the Air Force Institute of Technology. The focus groups identified requirements for the system intended to foster its acceptance within the user community. The conceptual framework posited user involvement in the design and implementation of the new system, providing a balance between functionality and ease of use fostering user acceptance. The framework was used to examine the relationships between the user’s involvement in the system design and implementation and its …

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Automated Document Conversion: A Manager's Perspective, Fredrick W. Knaak Iii Dec 1996

Automated Document Conversion: A Manager's Perspective, Fredrick W. Knaak Iii

Theses and Dissertations

Technological advances in our workplaces have made electronic documents pervasive throughout the USAF, DoD, and civilian world. Managers are recognizing the need to establish electronic document management systems to handle these diverse forms of documents. Unfortunately, they have been faced with essentially "reinventing the wheel," when it comes to determining which types of paper-based documents are best suited to conversion to an electronic format. There is also a lack of clearly identifiable cost factors associated with automated document conversion (ADC) for managers to use when conducting an economic analysis of a potential imaging application. This thesis addresses the problem of …

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A Preliminary Study Of Using The Sei's Capability Maturity Model To Set Statistical Control Bounds On Dod Contractor Cost And Schedule Performance, Jeffrey A. Schaefer Dec 1996

A Preliminary Study Of Using The Sei's Capability Maturity Model To Set Statistical Control Bounds On Dod Contractor Cost And Schedule Performance, Jeffrey A. Schaefer

Theses and Dissertations

Current methods for monitoring the performance of Department of Defense (DOD) software development contractors have not been successful in reversing the current trend of over budget and behind schedule software development. The DOD has adopted the Software Engineering Institute's (SEI's) Capability Maturity Model (CMM) as a method of determining the process maturity of a software developer with the idea that a more mature process will lead to improved cost and schedule performance. The goal of this research was to determine if a model based on the CMM rating level of a contractor could be developed and used in conjunction with …

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Using Kriging To Interpolate Spatially Distributed Volumetric Medical Data, Stephen M. Matechik Dec 1996

Using Kriging To Interpolate Spatially Distributed Volumetric Medical Data, Stephen M. Matechik

Theses and Dissertations

Routine cases in diagnostic radiology require the interpolation of volumetric medical imaging data sets. Inaccurate renditions of interpolated volumes can lead to the misdiagnosis of a patient's condition. It is therefore essential that interpolated modality space estimates accurately portray patient space. Kriging is investigated in this research to interpolate medical imaging volumes. Kriging requires data to be spatially distributed. Therefore, magnetic resonance imaging (MRI) data is shown to exhibit spatially regionalized characteristics such that it can be modeled using regionalized variables and subsequently be interpolated using kriging. A comprehensive, automated, three-dimensional structural analysis of the MRI data is accomplished to …

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Perceptual Fidelity For Digital Color Imagery, Curtis E. Martin Dec 1996

Perceptual Fidelity For Digital Color Imagery, Curtis E. Martin

Theses and Dissertations

The problem of measuring the fidelity of digital color images in a manner that corresponds to human perceptual assessments is addressed. Experiments are performed to validate human visual system (HVS) models, which provide access to a 'perceptual space' in which visual distortions may be measured, and then a model is proposed for assessing the perceptual fidelity of digital color image. Color Mach bands are produced in the first experiment, demonstrating that, as in the brightness channel, low spatial frequency attenuation occurs in the chromatic channels of the HVS. In the second experiment, a correlation between the chromatic channels of the …

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Electrical Characterization Of Intrinsic And Induced Deep Level Defects In Hexagonal Sic, James D. Scofield Dec 1996

Electrical Characterization Of Intrinsic And Induced Deep Level Defects In Hexagonal Sic, James D. Scofield

Theses and Dissertations

Deep level defects in hexagonal SiC were studied using digital deep level transient spectroscopy (DLTS) methods over the temperature range of 100 to 800 deg K. New centers were found in bulk and epitaxial 6H-SiC with ionization energies between 0.38 to 1.3 eV, and levels from 0.2 to 0.856 eV were identified in 4H-SiC epitaxy. Direct correlation between inequivalent lattice sites was identified for energetic pairs associated with both vanadium and ion implanted Mg impurities. Nonradioative carrier capture mechanisms were studied and deep level trapping was found to proceed via lattice relaxation multi-phonon emission, indicating efficient electronic lattice coupling in …

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Model Predictive Control Of Aerospace Systems, Derek W. Ebdon Dec 1996

Model Predictive Control Of Aerospace Systems, Derek W. Ebdon

Theses and Dissertations

The primary objective of this thesis is to explore the fault tolerance capabilities of a state space formulation of MPC. Subsequent to a simulated control surface failure on the F-18 High Alpha Research Vehicle (HARV), the MPC controller will attempt to maintain stability and nominal performance while tracking a setpoint. Secondary objectives include studying the effect of data sample rate and MPC horizon lengths on system performance. These objectives will be accomplished using Matlab to develop the MPC controller and Simulink to demonstrate its effectiveness through simulation.

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Performance Analysis Of A Liquid Metal Heat Pipe Space Shuttle Experiment, Timothy J. Dickinson Dec 1996

Performance Analysis Of A Liquid Metal Heat Pipe Space Shuttle Experiment, Timothy J. Dickinson

Theses and Dissertations

Future spacecraft technologies require advanced high-temperature thermal control systems. Liquid metal heat pipes are considered ideally suited for such applications. However, their behavior during microgravity operation is not yet understood. This study investigated liquid metal heat pipe performance in such an environment. Three stainless steel/potassium heat pipes were flown on space shuttle mission STS-77 in May 1996. The objectives of the experiment were characterization of the frozen startup and restart transients, comparison of flight and ground test data to establish a performance baseline for analytical model validation, and assessment of three different heat pipe designs. Heat pipe performance was characterized …

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Multidisciplinary And Multiobjective Optimization In Conceptual Design For Mixed-Stream Turbofan Engines, Luc J. J. P. Nadon Dec 1996

Multidisciplinary And Multiobjective Optimization In Conceptual Design For Mixed-Stream Turbofan Engines, Luc J. J. P. Nadon

Theses and Dissertations

Despite major advances in design tools such as engine cycle analysis software and computer aided design, conceptual gas turbine engine design is essentially a trial-and-error process based on the experience of engineers. Modern optimization concepts, such as multidisciplinary optimization (MDO), and multiobjective optimization (MOO), linked with sequential quadratic programming (SQP) methods and genetic algorithms (GA), were applied to the conceptual engine design process to automate the conceptual design phase. Robust integrated computer codes were created to find the optimal values of eight engine parameters in order to minimize fuel usage, aircraft cost and engine annulus area over a given mission. …

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Residual Strength And Fatigue Characterization Of Scs-6/Ti-6-4, Sang-Myung Lee Dec 1996

Residual Strength And Fatigue Characterization Of Scs-6/Ti-6-4, Sang-Myung Lee

Theses and Dissertations

Metal matrix composite have potential in a variety of aerospace applications, but they should be better understood before they can be employed. Despite the many studies that have contributed to characterizing the fatigue response of titanium alloy MMCs, few have researched the residual strength. The purpose of this study was to investigate the residual strength and the frequency effects on the residual strength of an unidirectional laminate of SCS-6/Ti-6-4, a titanium alloy matrix based composite under tension-tension, load-controlled conditions at elevated temperatures and different frequencies. Specimens were fatigued at frequencies of 1 and 0.01Hz, and at maximum stress of 900MPa …

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Influence Of Tip Clearance On The Flowfield In A Compressor Cascade With A Moving Endwall, Richard J. Mcmullan Dec 1996

Influence Of Tip Clearance On The Flowfield In A Compressor Cascade With A Moving Endwall, Richard J. Mcmullan

Theses and Dissertations

The effects of changing the blade tip clearances on the velocity and pressure flowfields within a compressor cascade were investigated in this experimental thesis. All moving endwall measurements were taken at a constant flow coefficient of 0.5 and tip clearances of 0.5, 1.0 and 2.0 percent chord. Hot-wire/film probes were used to determine the three-dimensional velocity vector components in various transverse planes - one upstream of the leading edges of the blades, three within the blade cascade and one downstream of the trailing edges of the blades. The transverse velocity vector plots showed a scraping of the tip leakage vortex …

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Investigation Of Ba, Bao, Sr And Sro Pulsed Laser-Induced Vapor Plumes In N2, O2, Microwave Discharged O2, And Vacuum At Low Laser Fluence, David L. Byers Dec 1996

Investigation Of Ba, Bao, Sr And Sro Pulsed Laser-Induced Vapor Plumes In N2, O2, Microwave Discharged O2, And Vacuum At Low Laser Fluence, David L. Byers

Theses and Dissertations

Ba, BaO, Sr and SrO were ablated by 248 nm laser pulses at fluences ranging from 270 mJ-/sq cm to 575 mJ-/sq cm in vacuum and in 25 mtorr atmospheres of N2, O2 and microwave-discharged O2. The spectral emissions of these plumes were compared for indications of ionization due to Ba or Sr collisions with each gas. The addition of a background gas increased the ion and neutral signature across the spectrum. SrO band emission was observed at 16,600-16,900/cm and possible BaO band emissions were observed in the 18,250-18,400/cm, 19,000-19700/cm and 19,800-20,000/cm regions. A screened plate ion probe was use …

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Unfolding The High Energy Electron Flux From Crres Fluxmeter Measurements, Brian D. Mckellar Dec 1996

Unfolding The High Energy Electron Flux From Crres Fluxmeter Measurements, Brian D. Mckellar

Theses and Dissertations

The Combined Release and Radiation Effects Satellite (CRRES) was launched on 25 July 1990 to collect measurements in the earth's radiation belts. One instrument, the High Energy Electron Fluxmeter (HEEF), measured the flux of electrons in 10 channels with energies between 1 MeV and 10 MeV. The channel sensitivities, Ri(E), have been calibrated and partially re-calibrated. We explore the errors introduced in unfolding the electron flux spectrum from the channel measurements and the propagation and growth of calibration and measurement errors. Using numerical experimentation, we fold the responses with known spectra to obtain simulated measurements, add random measurement and calibration …

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Simulation Based Performance Evaluation Of Resource Allocation Algorithms For Implementation In The Shf-Dama Satellite Network, Eric P. Hobson Dec 1996

Simulation Based Performance Evaluation Of Resource Allocation Algorithms For Implementation In The Shf-Dama Satellite Network, Eric P. Hobson

Theses and Dissertations

Sponsored by DISA, the SHF-DAMA Standard addresses the warfighter's requirements for flexible, reliable, and efficient (technically and fiscally) satellite communications. The Standard proposes a system supporting both packet data transfer and single-channel-per-carrier voice and data circuits assigned on a demand basis. The Standard does not address management of the DSCS 3 transponder's bandwidth and power resources among priority classes of users. This effort characterizes the SHF-DAMA system's performance over each combination of the following resource management algorithm features: (1) preemption enabled and disabled; (2) using the Standard-specified collision resolution technique and a binary exponential backoff; (3) using complete partitioning, complete …

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