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Air Force Institute of Technology

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A Comparison Of Variable Selection Criteria For Multiple Linear Regression: A Second Simulation Study, David P. Woollard Mar 1993

A Comparison Of Variable Selection Criteria For Multiple Linear Regression: A Second Simulation Study, David P. Woollard

Theses and Dissertations

This thesis implements a variable selection method proposed by Alan J. Miller, and makes an extension of Ross J. Hansen's 1988 thesis research by comparing the methods he examined: Minimum MSE, Minimum Sp, and Minimum Cp with Miller's method. Response Surface methodology is employed with two performance measures: the percentage of correct variables in a model and the Theoretical Mean Squared Error of Prediction (TMSEP). Each technique is applied on generated data with known multicollinearities, variances, random predictors, and sample sizes. Both performance measures are computed for models selected under each technique. A full factorial design using each performance measure …

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An Analysis Of Tactical Airlifter Characteristics And Their Impact On Theater Airlift System Performance, John J. Koger Mar 1993

An Analysis Of Tactical Airlifter Characteristics And Their Impact On Theater Airlift System Performance, John J. Koger

Theses and Dissertations

This study used computer simulation and Response Surface Technology to determine what tactical airlifter characteristics most impact theater airlift system performance in a Southwest Asia (SWA) scenario. Some Aircraft characteristics were grouped into functional sets, while others were considered individually. After screening one characteristic, reliability, with a two-level factorial experiment, a Box-Behnken design was used to estimate second-order metamodels. A stepwise regression procedure indicated that, if attrition rates are ignored, airlift system performance is most impacted by the aircraft's size, survivability, cruise speed, and ability to operate on short fields. The SWA scenario used in this study covers a large …

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Estimating Test Range Capacity, Paul A. Mcdaniel Mar 1993

Estimating Test Range Capacity, Paul A. Mcdaniel

Theses and Dissertations

The main focus of this thesis effort was to develop a means to estimate the capacity of the test range complex at Eglin AFB, Florida. For the purposes of this study, test range capacity was defined as the maximum number of missions, of a given set, that could possibly be supported by range resources on any given day. In trying to determine this number, the complexities of the overall multi-resource constrained scheduling problem dictated a more practical approach be taken in modeling the allocation process of range resources to test missions. Therefore, a series of three single-resource, 0-1 integer programming …

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Mitigation Of Shock Waves In A Cylindrical Tunnel By Foam, Grant W. Fondaw Mar 1993

Mitigation Of Shock Waves In A Cylindrical Tunnel By Foam, Grant W. Fondaw

Theses and Dissertations

This study investigated the effectiveness of foam linings in mitigating shock waves in tunnels. A polyurethane foam liner of varying density, crush strength and thickness was modeled inside a 1 meter radius tunnel and an explosion of 1.25 kg of plastic explosive was simulated. Using CTH, an Eulerian- Lagrangian hydrodynamics code from Sandia National Laboratories, the overpressures were computed and compared graphically to determine the effect of varying each foam parameter. The walls of the tunnel consisted of a perfectly reflecting boundary, and in some cases, a foam liner. Low density foam provided the most shock attenuation. with a 20 …

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Using Animation In The Validation Of Simulation Models, Michael L. Carpenter Mar 1993

Using Animation In The Validation Of Simulation Models, Michael L. Carpenter

Theses and Dissertations

This study examined three aspects of animation (movement, color, and detail of icons) to determine which one (or ones) best communicated the operation of a simulation model. The procedure was done in the context of using animation to establish a model's face validity. Movement, color, and detail of icons were looked at individually and in combination. The ability to communicate was measured both subjectively and objectively. The subjective measures were a selection of best and worst animation types where best and worst referred to how well an animation communicated, and a pairwise comparison of the animation types which resulted in …

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Understanding The Nature Of Bureaucracy: An Integration Of The Organizational And Public Choice Approaches, Rodney G. Vernon Mar 1993

Understanding The Nature Of Bureaucracy: An Integration Of The Organizational And Public Choice Approaches, Rodney G. Vernon

Theses and Dissertations

Bureaucracy is a term that has taken on different meanings in the academic literature since its inception. Vincent de Gournay first coined the term during the eighteenth century to describe the illnesses of rule by officials. Since that time, the term has evolved in organizational theory to describe a form of rational hierarchical organization in the public and private sector and at the same time, the public choice school describes it as a class of institution associated with inefficiency. This study reviews the literature on bureaucracy and incorporates the insights of Austrian economic theory on information, rules, and uncertainty to …

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Hoph Bifurcation In Viscous, Low Speed Flows About An Airfoil With Structural Coupling, Mark J. Lutton Mar 1993

Hoph Bifurcation In Viscous, Low Speed Flows About An Airfoil With Structural Coupling, Mark J. Lutton

Theses and Dissertations

The locations of Hopf bifurcation points associated with the viscous, incompressible flow about a NACA 0012 airfoil with structural coupling are computed for very low Reynolds numbers (<2000). A semi-implicit, first-order-accurate time integration algorithm is employed to solve the stream function-vorticity form of the Navier-Stokes equations. The formulation models the inclusion of simple structural elements affixed to the airfoil and captures the resulting airfoil motion. The equations describing the airfoil motion are integrated in time using a fourth-order Runge-Kutta algorithm. The dissertation is divided into two parts. In part one, numerical experiments are performed in the laminar regime to determine if the structural model of the airfoil has an effect upon the location of the Hopf bifurcation point when compared with the fixed airfoil. Results are reported for a variety of structural characteristics, including variations of torsional and linear spring constants, inertial properties, structural coupling, and structural damping. The structure of the solution space is explored by means of phase plots. In part two, the Baldwin-Lomax turbulence model is implemented to model turbulent flow. A numerical effort is made to predict the onset of unsteady flow.

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An Immersive Synthetic Environment For Observation And Interaction With A Large Volume Of Interest, Rex G. Haddix Iii Mar 1993

An Immersive Synthetic Environment For Observation And Interaction With A Large Volume Of Interest, Rex G. Haddix Iii

Theses and Dissertations

This thesis addresses the initial development of a Synthetic Battlebridge System designed to provide the user with a synthetic three- dimensional view of moving and stationary vehicles dispersed over a hundred thousand cubic mile volume. The system contains provisions to allow a user to view the battlefield either in the Polhemus LookingGlass™ fiber optic based high resolution head mounted display, a standard CRT, or through the Fake Space Labs BOOM2M™ high resolution monochrome display. Users can also video tape a session in the Synthetic Battlebridge System. A voice recognition system provides user interaction to the Synthetic Battlebridge System. Using a …

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Toward Reusable Graphics Components In Ada, Sam-Kyu Lim Mar 1993

Toward Reusable Graphics Components In Ada, Sam-Kyu Lim

Theses and Dissertations

This thesis demonstrates and illustrates a way of developing reusable graphics software components in Ada associated with a C++/C library. The work was carried out using object-oriented software development techniques that were used to analyze, design and implement a partial flight simulator. The objective of this thesis was to present a way of building reusable software components with Ada in a graphics application environment. An object-oriented approach was taken in the development of a set of reusable graphics software components for a flight simulator domain. A selection of a set of reusable software components came from domain analysis. These components …

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Rendering The Out-The-Window View For The Afit Virtual Cockpit, W. Dean Mccarty Mar 1993

Rendering The Out-The-Window View For The Afit Virtual Cockpit, W. Dean Mccarty

Theses and Dissertations

The Air Force Institute of Technology (AFIT) is developing a distributed interactive flight simulator, the Virtual Cockpit, using commercial graphics workstations and helmet mounted displays. The Virtual Cockpit communicates with other simulators via local and long-haul networks using the SIMNET protocol. The work reported in this thesis focuses on developing the terrain database for the synthetic environment and on rendering the pilot's view of the database. There are many different file formats for describing 3- dimensional geometric polygonal objects. An analysis of three formats, AFIT GEOM, the Naval Postgraduate School (NPS) DRP, and Software Systems' Flight, is presented. Each file …

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Development Of A Visual System Interface To Support A Domain-Oriented Application Composition System, Timothy L. Weide Mar 1993

Development Of A Visual System Interface To Support A Domain-Oriented Application Composition System, Timothy L. Weide

Theses and Dissertations

This research designed and prototyped a visual system interface to generate, display, and modify domain-oriented application specifications. A visual system interface, called the Architect Visual System Interface (AVSI), supplements a text-based environment, called Architect, previously developed by two other students. Using canonical formal specifications of domain objects, Architect rapidly composes these specifications into a software application and executes a prototype of that application as a means to demonstrate its correctness before any programming language specific code is generated. This thesis investigates visual techniques for populating, manipulating, viewing, and composing these software application specifications within the formal object base scheme required …

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A Distributed Object-Oriented Database Application Design, Hsin-Feng Edward Wu Mar 1993

A Distributed Object-Oriented Database Application Design, Hsin-Feng Edward Wu

Theses and Dissertations

The purpose of this study is to analyze and develop a distributed object-oriented database management system (DOODBMS) application to support parallel software development of the Parallel Algorithms and Applications Group (PAAG) at AFIT. By following the software lifecycle of object-oriented paradigm, this thesis investigation is intended to generate requirements analysis, design, implementation, user interface design and implementation, and integration of the database application with the user interface. ITASCA, an existing DOODBMS platform, has been chosen to prototype the application for its distribution functionalities and object-oriented modeling power. The user interface of the database application is based on X-window OSF/Motif front-end …

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Self-Referenced Speckle Holography (Srsh) Image Reconstruction Performance, John R. Devey Mar 1993

Self-Referenced Speckle Holography (Srsh) Image Reconstruction Performance, John R. Devey

Theses and Dissertations

The Speckle Holography technique uses a series of short exposure images and associated wave front sensor measurements to reconstruct astronomical images. The reconstruction technique effectively boosts the amplitude of high spatial frequencies to allow for finer resolution of astronomical objects. A simulation package that calculates the optical transfer function (OTF) of a telescopic system was previously developed for the Phillips Laboratory. This software was modified slightly to provide the Speckle Holography system transfer function (STF) for a telescopic system under varying seeing conditions.

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Frequency Domain Speech Compression Using The Karhunen-Loeve Transform, Donald W. Dryley Mar 1993

Frequency Domain Speech Compression Using The Karhunen-Loeve Transform, Donald W. Dryley

Theses and Dissertations

The purpose of this study was test the influence of phase on the quality of speech reproduced by a speaker dependent compression system. The tests consisted of compressing frequency domain speech vectors using the Karhunen-Loeve Transform, with and without phase, then making subjective judgements as to the reproduced quality. Error Metrics were then tested for their suitability as predictors of reproduced quality. The compression software transformed each speech vector into a vector of complex Fourier coefficients (only half of the coefficients are needed as transform is hermitian). Phase was preserved by using the real frequency components to form one vector …

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Characterization Of Laboratory Generated Turbulence By Optical Phase Measurements, Eric P. Magee Mar 1993

Characterization Of Laboratory Generated Turbulence By Optical Phase Measurements, Eric P. Magee

Theses and Dissertations

The resolution achieved by an optical imaging system in the presence of the random effects of the atmosphere is severely degraded from the theoretical diffraction limit. Techniques exist for recovering near diffraction limited performance of an imaging system in the presence of atmospheric turbulence. As opposed to laboratory testing, testing image enhancement techniques in the Earth's atmosphere imposes many limitations. Unfavorable weather conditions could result in the loss of time and money invested in conducting the experiments. With a properly characterized turbulence generator, with statistics that match those of the atmosphere, experimental testing of image enhancement techniques can be conducted …

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Afitbunki: A Modified Iterative Code To Unfold Neutron Spectra From Bonner Sphere Detector Data, Sean C. Miller Mar 1993

Afitbunki: A Modified Iterative Code To Unfold Neutron Spectra From Bonner Sphere Detector Data, Sean C. Miller

Theses and Dissertations

The neutron spectrum unfolding code BUNKI, developed at the Naval Research Laboratory in 1983, was modified to incorporate a finer energy group structure, seven initial-guess spectra, and new dose conversion factors. The modified code, AFITBUNKI, unfolds spectra into 54 energy groups between 10-7 and 14.92 MeV. The code calculates fluence, absorbed dose, percent of effective dose equivalent, and percent of ambient dose equivalent as a function of neutron energy. Additionally, AFITBUNKI calculates total energy-integrated fluence (Φ), absorbed dose (D), dose equivalent (H), effective quality factor (Q), ambient dose (D*), both ICRP Publication 26- and ICRP Publication 60-based ambient dose …

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Construction And Testing Of A Neutron And Gamma Spectrometry System Using Pulse Shape Discrimination With An Organic Scintillator, Robert S. Pope Mar 1993

Construction And Testing Of A Neutron And Gamma Spectrometry System Using Pulse Shape Discrimination With An Organic Scintillator, Robert S. Pope

Theses and Dissertations

The goal of this thesis was to construct and test a neutron detector to measure the energy spectrum of 1 to 14-MeV neutrons in the presence of gammas. A spectrometer based on the process of pulse shape discrimination (PSD) was constructed, in which the scintillator NE-213 was used. The primary neutron/ gamma sources used were 78-mCi and 4.7-Ci 239PuBe sources, while 4.7-µCi and 97.6-µCi 22Na gamma sources were used for energy calibration and additional testing of the detector. Proton recoil spectra and Compton electron spectra were unfolded with the neutron and gamma unfolding code FORIST to generate the …

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Identification Of Significant Outliers In Time Series Data, Keri L. Robinson Mar 1993

Identification Of Significant Outliers In Time Series Data, Keri L. Robinson

Theses and Dissertations

This thesis examines the feasibility of using least median of squares (LMS) procedure applied to a reweighted least squares (RLS) autoregression model to identify significant outliers in time series data. The time series were analyzed for data points that were outliers. In order to perform detailed analysis on an outlier. the analyst must be able to determine that an outlier data point is significantly different from normally distributed data. This thesis examines a new method for identifying these outliers. Data from the field were characterized and fit with time series models using an autoregressive reweighted least squares routine (ARRLS) derived …

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Cost Constrained Improvements To The Military Retirement System, Cynthia A. Brown Mar 1993

Cost Constrained Improvements To The Military Retirement System, Cynthia A. Brown

Theses and Dissertations

This research studies possible changes to the current military retirement system. The current military retirement system refers to the system provided under the Military Reform Act of 1986, A new system is proposed which would provide the retiree with four options. Option 1 would provide a pay annuity and medical benefits to the retiree (this is the current system). Option 2 would provide a pay lump sum in place of the, annuity and would offer medical benefits. Option 3 would offer the pay annuity but give a medical lump sum amount in place of the medical benefit. Finally, option 4 …

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Predicting The Productive Capacity Of Air Force Aerospace Ground Equipment Personnel Using Aptitude And Experience Measures, Robert S. Faneuff Mar 1993

Predicting The Productive Capacity Of Air Force Aerospace Ground Equipment Personnel Using Aptitude And Experience Measures, Robert S. Faneuff

Theses and Dissertations

This study investigated the effects of mechanical aptitude and job experience on the job performance of 204 Air Force Aerospace Group Equipment (AGE) mechanics. Job performance was expressed as productive capacity (PC), which is derived from estimated performance times on job tasks. PC measures were derived for 50 tasks typically performed by airmen in the specialty. Aptitude measures took the form of Mechanical percentile composite scores on the Armed Services Vocational Aptitude Battery (ASVAB). A second-order logistic model was used to regress PC on aptitude and experience at the task level and at the overall job, or aggregate, level. Model …

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Modified Anderson-Darling And Cramer-Von Mises Goodness-Of-Fit Tests For The Normal Distribution, David A. Gwinn Sr. Mar 1993

Modified Anderson-Darling And Cramer-Von Mises Goodness-Of-Fit Tests For The Normal Distribution, David A. Gwinn Sr.

Theses and Dissertations

New techniques for calculating goodness-of-fit statistics for normal distributions with parameters estimated from the sample are investigated. Samples are generated for a Normal(0,1) distribution. Critical values are calculated for five modifications to the Anderson-Darling statistic and five modifications to the Cramer-Von Mises statistic. An extensive power study is done to test the power of the new statistics versus the power of the unmodified statistics. Powers of six of the new statistics show minimal to no improvement, two of the new statistics show a marked decrease in power, and two of the new statistics show an overall increase in power over …

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Automating The Satellite Range Scheduling Process, Timothy D. Gooley Mar 1993

Automating The Satellite Range Scheduling Process, Timothy D. Gooley

Theses and Dissertations

Satellite range scheduling is a complex problem that involves scheduling satellite supports in which a satellite and a specific remote tracking station are assigned a time window during which they communicate with each other. As the number and complexity of satellite supports continue to increase, more pressure is placed on the current manual system to efficiently generate a schedule. The objective of this research was to develop a methodology that will automate the generation of the initial 24 hour schedule. The goal of the algorithm developed was to schedule as many conflict free supports as possible. A two phased approach …

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A Statistical Analysis Of Terrorism And Instability In Latin America, Juan A. Hurtado Mar 1993

A Statistical Analysis Of Terrorism And Instability In Latin America, Juan A. Hurtado

Theses and Dissertations

In this research the effect of socioeconomic factors on terrorism and government instability in Latin America are studied. A commonly held opinion is that terrorism and instability are caused by repressive conditions. The objective of this research was to generate a methodology to forecast terrorism and instability given certain socioeconomic indicators. This methodology was generated for individual countries, two groups of countries, and a composite developing country. A set of 28 socioeconomic factors were evaluated and reduced based on correlation analysis. Patterns of terrorism and instability were investigated through data analysis and factor analysis. Multiple regression was used to develop …

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A Monte Carlo Study Of The Raw And Normal Varimax Rotation Criterion In Factor Analysis, Willam M. Ibinson Mar 1993

A Monte Carlo Study Of The Raw And Normal Varimax Rotation Criterion In Factor Analysis, Willam M. Ibinson

Theses and Dissertations

Factor analysis is a multivariate statistical procedure for analyzing and reducing large data sets. Many factor analysis schemes and techniques are available that lead to strikingly different results from the same data. This research effort used a Monte Carlo approach to investigate the properties of two rotation methods for simple structure, Kaiser's raw and normal varimax criterion. Data sets were developed from a set of contrived experimental factor patterns by multiplying each factor pattern by its transpose to create a covariance matrix. Data sets of multivariate normal deviates were in turn generated from each covariance matrix via the Choleski algorithm. …

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Enhancements To The Animated Tutor For Air Combat Simulation, David A. Legge Mar 1993

Enhancements To The Animated Tutor For Air Combat Simulation, David A. Legge

Theses and Dissertations

This study investigates the use of the Ada programming language in combat modeling. It takes an existing combat model, the Animated Tutor for Air Combat Simulation (ATACS), and re-writes it into Ada. The new model also includes enhancements to the original model. ATACS+, as it is now called, is used as a learning tool in combat modeling classes at the Air Force Institute of Technology. ATACS+ consists of a preprocessor and a model, complete with two and three-dimensional graphics and engagement status reports. Conclusion are made about Ada's suitability for combat modeling, some of the features of Ada which can …

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Including Maximum Sustained Wind Speed In A Time Series Model To Forecast Hurricane Movement, Timothy B. Mott Mar 1993

Including Maximum Sustained Wind Speed In A Time Series Model To Forecast Hurricane Movement, Timothy B. Mott

Theses and Dissertations

Techniques for applying time series fundamentals to forecasting hurricane movement are thoroughly examined in this research. The objectives are: (1) to modify Dr. Thomas Curry's threshold autoregressive time series model to improve its ability to forecast hurricane movement, (2) to forecast the maximum sustained wind speed for a hurricane, and (3) to identify if wind speed should be included as an explanatory variable to aid in forecasting hurricane movement. Eleven different models to predict the latitude, longitude and maximum sustained wind speed are compared and contrasted with Curry's bivariate time series model. The results showed the modifications allow significant forecasting …

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A Modified Anderson Darling Goodness-Of-Fit Test For The Gamma Distribution With Unknown Scale And Location Parameters, Tamer Ozmen Mar 1993

A Modified Anderson Darling Goodness-Of-Fit Test For The Gamma Distribution With Unknown Scale And Location Parameters, Tamer Ozmen

Theses and Dissertations

A new modified Anderson-Darling goodness-of-fit test is introduced for the three-parameter Gamma distribution when the location parameter is found by minimum distance estimation and scale parameter by maximum likelihood estimation. Monte Carlo simulation studies were performed to calculate the critical values for A-D test when A-D statistic is minimized. These critical values are then used for testing whether a set of observations follows a Gamma distribution when the scale and location parameters axe unspecified and are estimated from the sample. Functional relationship between the critical values of A-D is also examined for each shape parameter by the variables, sample size …

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Optimal Silo Attack Plan For The Red Integrated Strategic Offensive Plan (Risop), Richard C. Pace Mar 1993

Optimal Silo Attack Plan For The Red Integrated Strategic Offensive Plan (Risop), Richard C. Pace

Theses and Dissertations

The Joint Staff Directorate for Force Structure, Resources, and Assessment (J-8) sought a procedure which could be used to generate an optimal missile allocation for the silo attack portion of the Red Integrated Strategic Offensive Plan (RISOP). Their current solution procedure is a manual heuristic which is time-consuming and is not guaranteed to lead to an optimal solution. J- 8 defines an optimal solution as a feasible solution which minimizes both the flight time of the missile that impacts first and the duration of the attack. J- 8 defined several input rules which limit how missiles may be allocated. A …

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Integrating Psychological Operations Into The Joint Theater Level Simulation (Jtls), C. Matthew Pecot Iii Mar 1993

Integrating Psychological Operations Into The Joint Theater Level Simulation (Jtls), C. Matthew Pecot Iii

Theses and Dissertations

This thesis provides a prototype and methodology for integrating psychological operations (PSYOP) into the Joint Theater Level Simulation (JTLS) combat model. The requirement rose out of the need for aggregate-level training models to reflect the role of PSYOP so that commanders and their staffs can learn how to manage plan for, and conduct PSYOP within the context of AirLand battle doctrine. As the JTLS model currently exists, there is no representation of psychological operations whatsoever. This thesis outlines a methodology for incorporating the PSYOP analysis process (including the target audience analysis), the PSYOP product development and production process, the PSYOP …

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Scheduling Air Mobility Command's Channel Cargo Missions, Gregory S. Rau Mar 1993

Scheduling Air Mobility Command's Channel Cargo Missions, Gregory S. Rau

Theses and Dissertations

Through the use of a linear programming model, this research revised the initial schedule for AMC's channel cargo missions to eliminate any excess delay enroute by minimizing the cumulative, weighted time-in-system for all cargo, according to a given cargo flow. In fact, the revised schedule minimizes any assigned nonnegative weighting of the time-in-system, due to the properties of equivalent measures of performance. When combined with Step One of a proposed two-step process for revising AMC's channel mission schedule, this research can be used to improve the current schedule based on Step One's cargo flow. By carefully defining the notation and …

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