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Air Force Institute of Technology

Theses/Dissertations

1998

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Articles 31 - 60 of 75

Full-Text Articles in Engineering

Using Simulation To Model Time Utilization Of Army Recruiters, James D. Cordeiro Jr., Mark A. Friend Mar 1998

Using Simulation To Model Time Utilization Of Army Recruiters, James D. Cordeiro Jr., Mark A. Friend

Theses and Dissertations

It is a well-known fact Army recruiters work very long hours in a demanding environment. In many cases, recruiting stations are geographically isolated from military bases, with recruiters often tolerating a high cost of living, crime, and other such adverse conditions that characterize the communities they work in. The job itself demands self-starting, motivated individuals with a wide range of skills, from street-savvy to salesmanship, in order to succeed. A number of factors in recent years have made military recruiting more difficult, which include scandals involving highly-placed soldiers and changes in attitudes towards military service among eligible men and women. …

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An Evaluation Of Frequency Domain Ensemble Averaging To Improve Aircraft Stability Derivative Estimation, Lawrence M. Hoffman Mar 1998

An Evaluation Of Frequency Domain Ensemble Averaging To Improve Aircraft Stability Derivative Estimation, Lawrence M. Hoffman

Theses and Dissertations

This research evaluated a process to improve aircraft stability derivative estimation results. The Have Derivatives process used overlap ensemble averaging in the frequency domain to minimize noise on the original time domain signals. The process estimated average complex frequency response functions that were then transformed back into the time domain as a set of discrete pulse responses with far less noise than the original signals. These clean signals were used in a parameter estimation program to estimate better stability derivatives than were estimated with the original noisy signals. Both simulation and flight test data were used to study the effects …

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Application Of Decision Analysis To Evaluate Alternative Research And Development Investments., Michael J. Artelli Mar 1998

Application Of Decision Analysis To Evaluate Alternative Research And Development Investments., Michael J. Artelli

Theses and Dissertations

This thesis is an application of decision analysis techniques to the problem of evaluating competing research and development investments and selecting the best portfolio from among the alternatives. In contrast to the current ad hoc approach, decision analysis provides an explicit and easily explained rationale for investment choices, complete and consistent incorporation of multiple objectives, and direct insight into the effects of uncertain investment returns. A hierarchical objective decomposition was used to capture the user's preference structure. The hierarchy was then used to develop a computer-based decision aid to allow the users to quickly and consistently evaluate technology investment options. …

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A Game-Theoretic Improvement Model For Stochastic Networks: Reliability Vs. Throughput, Jeffrey A. Schavland Mar 1998

A Game-Theoretic Improvement Model For Stochastic Networks: Reliability Vs. Throughput, Jeffrey A. Schavland

Theses and Dissertations

Prescriptive models used to allocate resources for network improvement traditionally have used reliability or flow as Measures of Effectiveness (MOEs). Such metrics do not give value to efforts which make a component more difficult to exploit. This study developed an entirely new MOE for stochastic network improvement, flow damage utility, which uses a two person, zero-sum, non-cooperative game to optimize a probabilistic network for an estimate of expected flow minus performance degradation after a worst case component loss. A multiple criteria optimization problem that uses flow damage utility and an analogous, previously developed metric for the reliability problem is used …

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Effect Of High Free Stream Turbulence On Film Cooling Using Double Row Of 30° Slant-Hole Injectors, Lilith I. Sorensen Mar 1998

Effect Of High Free Stream Turbulence On Film Cooling Using Double Row Of 30° Slant-Hole Injectors, Lilith I. Sorensen

Theses and Dissertations

In this study free stream turbulence levels from 7.3% to 17.8% are applied to film cooling over a flat plate with two rows of 30° slant holes using a wall jet as the main stream air supply and source of turbulence. Blowing ratios are varied from 0.25 to 2.0 and free stream velocities at injection range from 10 m/s to 85 m/s. A constant density ratio of 1.07 is kept throughout the experiment. Results show that for different magnitudes of blowing ratio free stream turbulence has a different influence on effectiveness. At the forward stations, where blow off was present …

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Using Bayesian Statistics In Operational Testing, Thuan H. Tran Mar 1998

Using Bayesian Statistics In Operational Testing, Thuan H. Tran

Theses and Dissertations

This research explored the applicability of Bayesian methods to the problem of determining the reliability of a series system, a parallel system, and a bridge system. The time to failure of each component in each system is assumed to be exponentially distributed. A basic exponential case and a basic binomial case are also evaluated. In general, using simulated data and real data when possible, the Bayesian methods produced confidence intervals that were much tighter than the classical inference methods, thus allowing a decision maker to have higher confidence in making a decision. System level data and aggregated component level data …

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A New Sequential Goodness Of Fit Test For The Three-Parameter Weibull Distribution With Known Shape Based On Skewness And Kurtosis, Jonathan C. Clough Mar 1998

A New Sequential Goodness Of Fit Test For The Three-Parameter Weibull Distribution With Known Shape Based On Skewness And Kurtosis, Jonathan C. Clough

Theses and Dissertations

The Weibull distribution finds wide applicability across a broad spectrum of disciplines and is very prevalent in reliability theory. Consequently, numerous statistical tests have been developed to determine whether sample data can be adequately modeled with this distribution. Unfortunately, the majority of these goodness-of-fit tests involve a substantial degree of computational complexity. The study presented here develops and evaluates a new sequential goodness-of-fit test for the three-parameter Weibull distribution with a known shape that delivers power comparable to popular procedures while dramatically reducing computational requirements. The new procedure consists of two distinct tests, using only the sample skewness and sample …

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Sensitivity Analysis Of The Thunder Combat Simulation Model To Command And Control Inputs Accomplished In A Parallel Environment, David A. Davies Mar 1998

Sensitivity Analysis Of The Thunder Combat Simulation Model To Command And Control Inputs Accomplished In A Parallel Environment, David A. Davies

Theses and Dissertations

This research had two objectives. The first was to develop a methodology to demonstrate the parallel processing capability provided by Air Force's Aeronautical System's Command (ASC) Major Shared Resource Center (MSRC) and apply that methodology to the SIMAF Proof of Concept project. Secondly, AFSAA/SAAB requested a sensitivity analysis of THUNDER to the modeled command and control (C2) inputs. The power of parallelization can not be overemphasized. The data collection phase of this thesis was accomplished at the MSRC using a script developed to automate the processing of an experimental design, providing the analyst with a launch and leave capability. On …

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A Life Cycle Cost Model For Innovative Remediation Technologies, Osman S. Dereli Mar 1998

A Life Cycle Cost Model For Innovative Remediation Technologies, Osman S. Dereli

Theses and Dissertations

LCC analysis is a powerful tool for investigating the costs of competing systems. This thesis investigates the cost scaling methods to improve the traditional LCC modeling techniques. The motivation for this research is finding a good estimate for the remediation technologies when the contaminant volume is not exactly known. This specific case lead researcher to investigating the methods of cost scaling and effects of inflation in the cost estimation. As a result of study a generic LCC model is developed. Methods for considering inflation and scaling are recommended and embodied into the model. The developed model is applied the specific …

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An Airlift Hub-And-Spoke Location-Routing Model With Time Windows: Case Study Of The Conus-To-Korea Airlift Problem, David W. Cox Mar 1998

An Airlift Hub-And-Spoke Location-Routing Model With Time Windows: Case Study Of The Conus-To-Korea Airlift Problem, David W. Cox

Theses and Dissertations

Traditionally, the United States Air Force's Air Mobility Command (AMC) has used the concept of direct delivery to airlift cargo and passengers from a point of embarkation to a point of debarkation. This study develops an alternative hub-and-spoke combined location-routing integer linear programming prototype model, and uses this model to determine what advantages a hub-and-spoke system offers, and in which scenarios it is better-suited than the direct delivery method. Additionally, the analysis suggests that the C-17 may be better-suited, in certain airlift situations, for theater airlift versus strategic (direct delivery) airlift. The model features the following elements: time windows, cargo …

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Cross-Resolution Combat Model Calibration Using Bootstrap Sampling, Bryan S. Livergood Mar 1998

Cross-Resolution Combat Model Calibration Using Bootstrap Sampling, Bryan S. Livergood

Theses and Dissertations

The US Air Force uses many combat simulation models to assist them in performing combat analyses. BRAWLER is a high-resolution air-to-air combat simulation model used for engagement-level analyses of few-on-few air combat. THUNDER is a low-resolution combat simulation model used for campaign-level analyses of theater-level warfare. BRAWLER is frequently used to ensure that THUNDER air-to-air inputs are valid. This thesis describes the confederation of THUNDER and BRAWLER by clearly showing how one particular BRAWLER output, the effectiveness of a missile type, is transformed into THUNDER air-to-air input data. Since BRAWLER is a stochastic simulation model, it is necessary to replicate …

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An Advanced Visualization Method For An Operations Research Analysis, Steven C. Oimoen Mar 1998

An Advanced Visualization Method For An Operations Research Analysis, Steven C. Oimoen

Theses and Dissertations

Visualizing multidimensional data using only two dimensions and conventional visualization techniques limits the understanding of the data set. Underlying structures or patterns within the data can easily go unnoticed. In order to gain additional insight into an analysis, incorporation of visualization and multidimensional graphics into the analysis results should be accomplished. The results must ensure that the information portrayed is not misleading or misunderstood. The integrity of the data must be preserved throughout the transformation. The primary objective of this research effort is to identify techniques to visualize multidimensional data and then develop a software tool to display the multidimensional …

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Sensitivity Analysis Of Brawler Pilot Skill Levels, Daniel C. Buschor Mar 1998

Sensitivity Analysis Of Brawler Pilot Skill Levels, Daniel C. Buschor

Theses and Dissertations

BRAWLER is a high resolution air to air combat simulation model used for engagement level analyses of few on few air combat. It uses a value driven decision logic to help simulate pilot behavior. In order to account for varied pilot skill levels, BRAWLER has defined three skill levels; Rookie, Pilot, and Ace. A Rookie can track up to three aircraft in its mental model, the Pilot, up to five aircraft, while an Ace has no limit. Further, each skill level varies the amount of time before a known aircraft, which has not been recently observed, is purged from the …

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Solving Geometric Knapsack Problems Using Tabu Search Heuristics, Christopher A. Chocolaad Mar 1998

Solving Geometric Knapsack Problems Using Tabu Search Heuristics, Christopher A. Chocolaad

Theses and Dissertations

An instance of the geometric knapsack problem occurs in air lift loading where a set of cargo must be chosen to pack in a given fleet of aircraft. This paper demonstrates a new heuristic to solve this problem in a reasonable amount of time with a higher quality solution then previously reported in literature. We also report a new tabu search heuristic to solve geometric knapsack problems.

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Performance Of Imaging Laser Radar In Rain And Fog, Kathleen M. Campbell Mar 1998

Performance Of Imaging Laser Radar In Rain And Fog, Kathleen M. Campbell

Theses and Dissertations

The Air Force is currently developing imaging laser radar systems (ladar) for use on precision guided munitions and other imaging systems. Scientists at Eglin Air Force Base, in conjunction with Wright Laboratories, are testing a 1.06-um wavelength ladar system and need to understand the weather effects on the ladar images. As the laser beam propagates through the atmosphere, fog droplets and raindrops can cause image degradation, and these image degradations are manifested as either dropouts or false returns. An analysis of the dropouts and false returns helped to quantify the performance of the system in adverse weather conditions. Statistical analysis …

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Generating Bomber Routes For The Delivery Of Gravity Weapons, Gregory J. Ehlers Mar 1998

Generating Bomber Routes For The Delivery Of Gravity Weapons, Gregory J. Ehlers

Theses and Dissertations

United States Strategic Command (USSTRATCOM) is updating the Arsenal Exchange Model (AEM) that it uses for allocating strategic weapons to targets. AEM does not model the range constraints on bomber routes. These routes are used to deliver gravity munitions. In order to include these constraints in the new method, the Weapons Allocation Model (WAM), a pool of routes that satisfy the range constraints needs to be created. The number of possible routes to consider is extremely large and it is not possible to enumerate them all. Therefore, the method to form the pool of routes needs to reduce the number …

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Channel-Mismatch Compensation In Speaker Identification Feature Selection And Adaptation With Artificial Neural Networks, Edmund A. Fitzgerald Mar 1998

Channel-Mismatch Compensation In Speaker Identification Feature Selection And Adaptation With Artificial Neural Networks, Edmund A. Fitzgerald

Theses and Dissertations

We develop and present results of an artificial neural network (ANN) based compensation technique for mismatched classifier training and testing conditions in speaker identification (SID). One ANN per feature per speaker is trained to perform a mapping of that feature from a corrupted condition to an undistorted condition. Therefore, a classifier trained under one condition may be used to classify data collected under a different condition. Speech utterances from 168 speakers, collected in a studio, and also re-recorded after transmission over telephone networks, are used for developing and testing the method. Peak formant resonant frequencies, their bandwidths, and pitch are …

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Anderson-Darling And Cramer-Von Mises Based Goodness-Of-Fit Tests For The Weibull Distribution With Known Shape Using Normalized Spacings, Eric W. Frisco Mar 1998

Anderson-Darling And Cramer-Von Mises Based Goodness-Of-Fit Tests For The Weibull Distribution With Known Shape Using Normalized Spacings, Eric W. Frisco

Theses and Dissertations

Two new goodness-of-fit tests are developed for the three-parameter Weibull distribution with known shape parameter. These procedures eliminate the need for estimating the unknown location and scale parameters prior to initiating the tests and are easily adapted for censored data. This is accomplished by employing the Anderson-Darling and Cramer-von Mises statistics based on the normalized spacings of the sample data. Critical values of the new tests are obtained for common significance levels by large Monte Carlo simulations for shapes 0.5(0.5)4.0 and sample sizes 5(5)40 with up to 40% censoring (Type II) from the left and/or right. An extensive Monte Carlo …

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An Operational Review Of Air Campaign Planning Automation, William R. Haas Mar 1998

An Operational Review Of Air Campaign Planning Automation, William R. Haas

Theses and Dissertations

The air campaign planning process is a complex and dynamic process. Operations research has been applied to this problem to shorten the planning cycle with mixed results. The Joint Force Air Component Commander Planning Tool was developed as an air campaign planning aid. It uses the Conventional Targeting and Effectiveness Model (CTEM) as the force analysis model for master air attack plan (MAAP) planning. This thesis reviews the limitations and assumptions of CTEM and CTEM in JPT from and operational perspective. A new approach to using models in air campaign planning, collaborative planning, is being developed for use with JPT. …

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Investigating Sorbent Geometry Response Surfaces From Sorption Rate Data, H. Michael Harrison Mar 1998

Investigating Sorbent Geometry Response Surfaces From Sorption Rate Data, H. Michael Harrison

Theses and Dissertations

Sorption and desorption of hydrophobic organic compounds (HOCs) into soil particles occurs at Air Force contamination sites. Long-term desorption extends clean up time, costing billions. Accurately modeling desorption will reduce costs and improve clean up designs. State of the art models depict soil as uniform spherical particles which lose the effect of longer sorption path lengths. An alternate approach, the multiple sites in series (MSS) model, describes the sorption capacity of a mixture of soil particle sizes and shapes using a composite particle defined by a two parameter statistical distribution. When the MSS model uses a general radial geometry function …

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A Value Focused Thinking Approach To Academic Course Scheduling, Shane A. Knighton Mar 1998

A Value Focused Thinking Approach To Academic Course Scheduling, Shane A. Knighton

Theses and Dissertations

In 1997, the School of Engineering of the United States Air Force Institute of Technology began exploring ways of automating the academic course scheduling process. The administration desired an expedient approach for course scheduling which supports the institute's mission of "providing scientific and technological education" to officers from all branches of military service, as well as international military forces. The scheduling approach needed to be flexible, efficient, and represent the institute's values and principles. Decision Analysis (DA) and specifically, Value Focused Thinking (VFT), is used to decompose the complex problem of academic course scheduling and determine the factors that are …

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A Network Disruption Modeling Tool, James A. Leinart Mar 1998

A Network Disruption Modeling Tool, James A. Leinart

Theses and Dissertations

Given that network disruption has been identified as a military objective and C2-attack has been identified as the mechanism to accomplish this objective, a target set must be acquired and priorities assigned to each target set. In order to move beyond subjective target prioritization, development and implementation of a methodology and model, that quantitatively measures the value of each target in achieving the objective, is needed in prioritizing targets. This thesis effort uses a vertex cut-set algorithm on a transformation of the graph representing a notional network of interest. The cut-sets generated represent potential target sets. Value-focused thinking and decision …

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Real Time Detection Of Anomalous Satellite Behavior Has Ground Based Telescope Images, Geoffrey S. Maron Mar 1998

Real Time Detection Of Anomalous Satellite Behavior Has Ground Based Telescope Images, Geoffrey S. Maron

Theses and Dissertations

Air Force analysts are faced with the task of monitoring satellites with ground based telescopes. Images are collected and analyzed in a time consuming and subjective effort to detect any behavior that is anomalous. This research maximizes use of a priori information to create an automated, real time satellite behavior classification tool. Using modeling software and knowledge of a satellite's orbit, reference imagery is created for each measured image in a satellite pass. Features are extracted from the measured and reference image pairs that provide good overall Gaussian classification accuracy (85%), reduce the dimensionality of the problem (from 32,768 down …

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Optimizing The Efficiency Of A Multi-Stage Axial-Flow Compressor: An Application Of Stage-Wise Optimization, Shawn A. Miller Mar 1998

Optimizing The Efficiency Of A Multi-Stage Axial-Flow Compressor: An Application Of Stage-Wise Optimization, Shawn A. Miller

Theses and Dissertations

The development of jet engines has become an integral part of maintaining air superiority. In order to achieve the most advanced engine, research has turned to traditional optimization methods to aid in creating new engine designs. To develop simplified mathematical models representative of the engine, the engine can be separated into its components. A jet engine has three major elements, the compressor, combustion chamber and turbine. This research attempts to make an initial analysis of a two stage compressor to determine values of blade angles and spacing to chord ratios for both stages that produce the highest possible efficiency for …

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Improved Mathematical Modeling For Gps Based Navigation, Salvatore Nardi Mar 1998

Improved Mathematical Modeling For Gps Based Navigation, Salvatore Nardi

Theses and Dissertations

This thesis is concerned with the development of new closed form GPS position determination algorithms that work in the presence of pseudorange measurement noise. The mathematical derivation of two closed form algorithms, based on stochastic modeling and estimation techniques, is presented. The algorithms provide an estimate of the GPS solution parameters (viz., the user position and the user clock bias) as well as the estimation error covariance. The experimental results are analyzed by comparison to the baseline results from the conventional Iterative Least Squares (ILS) algorithm. In typical GPS scenarios, the closed form algorithms are extremely sensitive to noise, making …

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Preliminary Design Of A Joint Simulation, Analysis, And Wargaming Center For The Turkish General Staff, Oguz Okuyucu Mar 1998

Preliminary Design Of A Joint Simulation, Analysis, And Wargaming Center For The Turkish General Staff, Oguz Okuyucu

Theses and Dissertations

This study develops a framework for the design of a Joint Simulation, Analysis, and Wargaming Center (JSAWC). JSAWC is proposed as the primary decision support center for the Turkish General Staff. The complexity of warfare systems and the fog of future wars make military planning, problem solving, and decision making processes difficult to accomplish without using computerized analysis support tools. The proposed JSAWC will use modeling and simulation technology to provide analytical support for Turkish military decision-makers and planners in operations planning, force structuring, and training. An iterative systems engineering process is defined and applied to the primary design of …

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A Variable-Complexity Modeling Approach To Scramjet Fuel Injection Array Design Optimization, Michael D. Payne Mar 1998

A Variable-Complexity Modeling Approach To Scramjet Fuel Injection Array Design Optimization, Michael D. Payne

Theses and Dissertations

The analysis of fuel air mixing in a scramjet is often accomplished either with Computational Fluid Dynamics (CFD) algorithms or through experimental research. These approaches, while accurate and reliable, are extremely expensive and thus not well suited for use with conventional design optimization methods. In this investigation, Variable Complexity Modeling (VCM) is used to significantly reduce the number of complex, expensive analyses required to optimize the design of a scramjet fuel injection array. A design problem formulation for a lateral transverse injection array is developed and a VCM approach to design optimization is conducted in two stages. Initially, a simplified …

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Verification And Validation Of Faarr Model And Data Envelopment Analysis Models For United States Army Recruiting, Gene M. Piskator Mar 1998

Verification And Validation Of Faarr Model And Data Envelopment Analysis Models For United States Army Recruiting, Gene M. Piskator

Theses and Dissertations

This research has two objectives-to verify and validate the U.S. Army's Forecast and Allocation of Army Recruiting Resources (FAARR) model and to develop a Data Envelopment Analysis (DEA) modeling strategy. First, the FAARR model was verified using a simulation of a known production function and validated using sensitivity analysis and ex-post forecasts. FAARR model forecasts were not accurate and were extremely sensitive to any changes in the model's linear programming constraints and to changes in recruiting resource levels. Second, this research describes a three phase modeling strategy to build accurate DEA models. DEA has become a popular tool to evaluate …

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Embedding A Reactive Tabu Search Heuristic In Unmanned Aerial Vehicle Simulations, Joel L. Ryan Mar 1998

Embedding A Reactive Tabu Search Heuristic In Unmanned Aerial Vehicle Simulations, Joel L. Ryan

Theses and Dissertations

We apply a Reactive Tabu Search (RTS) heuristic within a discrete event simulation to solve routing problems for Unmanned Aerial Vehicles (UAVs). Our formulation represents this problem as a multiple Traveling Salesman Problem with time windows (mTSPTW), with the objective of attaining a specified level of target coverage using a minimum number of vehicles. Incorporating weather and probability of UAV survival at each target as random inputs, the RTS heuristic in the simulation searches for the best solution in each realization of the problem scenario in order to identify those routes that are robust to variations in weather, threat, or …

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Analysis Of Alternatives: Multivariate Considerations, John J. Siegner Mar 1998

Analysis Of Alternatives: Multivariate Considerations, John J. Siegner

Theses and Dissertations

The Aeronautical System Center (ASC) is developing a Simulation and Analysis Facility (SIMAF) that will link models, simulations, hardware-in-the-loop, and system-in-the-loop resources to create a robust virtual environment supporting assessment of alternate systems in the defense acquisition process. ENS is assisting ASC with scenario development, experimental design, and battleroom visualization efforts for a SIMAF capability demonstration. This thesis uses multivariate analysis and visualization tools to develop an approach for reducing the dimensionality of multiple campaign level measures of effectiveness for a notional Analysis of Alternatives (AoA) study. Additionally, the thesis advances an AoA visualization paradigm for the SIMAF capability demonstration. …

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