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Articles 391 - 420 of 602
Full-Text Articles in Operational Research
Portfolio Selection Of Innovative Technologies Via Life Cycle Cost Modeling, Scott C. Naylor
Portfolio Selection Of Innovative Technologies Via Life Cycle Cost Modeling, Scott C. Naylor
Theses and Dissertations
High technology firms are faced with the dilemma of deciding which products to develop, which generations of technology to pass over, and which products to skip entirely. As competition among these firms increases and the life cycles of technological products shorten, there exists a great deal of pressure to bring products rapidly to the market. As a result, recouping the costs of research and development (R & D) and earning a profit becomes increasingly uncertain. Traditional life cycle cost models do not directly address shortened life cycles, time to market, or learning curve issues; all are critical factors in the …
A Validation Assessment Of Thunder 6.5'S Intelligence, Surveillance, And Reconnaissance Module, Francine N. Nelson
A Validation Assessment Of Thunder 6.5'S Intelligence, Surveillance, And Reconnaissance Module, Francine N. Nelson
Theses and Dissertations
A validation assessment of THUNDER 6.5's Intelligence, Surveillance, and Reconnaissance (ISR) module is accomplished using formulational and experimental validation techniques. A comparison of ISR purposes and processes according to military doctrine is made with the purposes and processes of ISR implemented within THUNDER 6.5. This comparison provides an overview of the process, an understanding of the level of aggregation within THUNDER, insight into possible problem areas in THUNDER, and a basis for improving THUNDER ISR processes. Sensitivity analysis of the ISR parameters as they relate to the Quality, Quantity, and Timeliness of ISR is also presented to provide insight into …
Solving The Multidimensional Multiple Knapsack Problem With Packing Constraints Using Tabu Search, Jonathan M. Romaine
Solving The Multidimensional Multiple Knapsack Problem With Packing Constraints Using Tabu Search, Jonathan M. Romaine
Theses and Dissertations
This paper presents a methodology for solving military aircraft load-scheduling problems modeled as a multidimensional multiple knapsack problem, Because of the computational time associated with applying conventional algorithms to this type of problem, we employ tabu search to determine how much cargo a heterogeneous group of aircraft can carry. This study extends the previous work of Chocolaad in two areas. First, we modify Chocolaad's algorithms to solve the multiple (rather than the single) knapsack problem under the constraints he defined for the Airlift Loading Problem. Second, we drop his assumption of a homogeneous group of aircraft. We validate our model …
A Value Focused Approach To Determining The Top Ten Hazards In Army Aviation, Brian K. Sperling
A Value Focused Approach To Determining The Top Ten Hazards In Army Aviation, Brian K. Sperling
Theses and Dissertations
The United States Army Safety Center is challenged with identifying the top ten most severe hazards in Army Aviation. This research utilizes value-focused thinking and multiattribute preference theory concepts to produce a decision analysis model designed to aid decision-makers in their analysis process. The severity model is based on the Army's Risk Management doctrinal manual and has been tailored specifically for aviation related accidents and hazards. The model determines the severity and risk ranking for 65 categories of accidents and 24 existing hazards. A sensitivity analysis is conducted to examine the effects of variations in the weights of the top-level …
Unmanned Aerial Vehicle Mission Level Simulation, Jennifer G. Walston
Unmanned Aerial Vehicle Mission Level Simulation, Jennifer G. Walston
Theses and Dissertations
We develop an object-oriented simulation that models the surveillance and Active Suppression of Enemy Air Defense (SEAD) missions of the Unmanned Aerial Vehicle (UAV) RQ-1A Predator. The simulation, written in Java using the Silk simulation package, interfaces with a Reactive Tabu Search routing algorithm to provide optimal UAV routes. The routing algorithm is called by the simulation to account for changes in weather conditions and to provide a means of dynamically retasking the UAV. The simulation and analysis support a UAV Battlelab initiative to test the operational effects of proposed changes in Predator performance and UAV capability to perform in …
A New Sequential Goodness-Of-Fit-Test For The Three-Parameter Weibull Distribution With Known Shape Parameter Value Based On Skewness And Q-Statis G.O.F. Test Statistics, Tibet Memis
Theses and Dissertations
Due to its flexibility, the Weibull distribution has very wide applicability in a lot of disciplines and is very prevalent in reliability theory. Thus, a lot of statistical tests that generally have a substantial degree of computational complexity have been developed to determine if the data at hand can be represented with this distribution. This research presents a new omnibus goodness-of-fit test (G.O.F.) that has less computational complexity than the existing tests for the three-parameter Weibull distribution using a sequential application of two individual tests, sample skewness and Q-Statistic. A Monte Carlo procedure has been employed to generate critical values …
A New Sequential Goodness Of Fit Test For The Three-Parameter Gamma Distribution With Known Shape Based On Skewness And Kurtosis, Chil Ho Park
Theses and Dissertations
This research presents a new sequential goodness of fit test for the three-parameter gamma distribution with a known shape. The test is accomplished by employing two new tests, sample skewness and sample kurtosis, sequentially as test statistics. Unlike the typical goodness of fit test, using parameter estimation methods such as maximum likelihood estimation and minimum distance estimation, this test using the two test statistics above does not involve a substantial degree of computational complexity. Large Monte Carlo simulation has been used to determine critical values and overall significance levels for all combinations of the two tests, and to conduct extensive …
Technology Selection For The Air Force Research Laboratory Air Vehicles Directorate: An Analysis Using Value Focused Thinking, Michael F. Winthrop
Technology Selection For The Air Force Research Laboratory Air Vehicles Directorate: An Analysis Using Value Focused Thinking, Michael F. Winthrop
Theses and Dissertations
A technology selection model was developed for the Air Vehicles Directorate of Air Force Research Laboratory. The model was developed and demonstrated to aid in addressing the question of what technologies Air Vehicles' should invest in to remain consistent with Air Force values. Both Value-Focused Thinking and optimization approaches were used to identify the value of Air Vehicles technology, to provide insights to Air Vehicles' decision-makers, to determine where value gaps might exist with the scored alternatives, and to determine how sensitive the model was to changes. As a demonstration of the approach, seven technologies were scored, representing all three …
Feature Saliency In Artificial Neural Networks With Application To Modeling Workload, Kelly A. Greene
Feature Saliency In Artificial Neural Networks With Application To Modeling Workload, Kelly A. Greene
Theses and Dissertations
This dissertation research extends the current knowledge of feature saliency in artificial neural networks (ANN). Feature saliency measures allow for the user to rank order the features based upon the saliency, or relative importance, of the features. Selecting a parsimonious set of salient input features is crucial to the success of any ANN model. In this research, several methodologies were developed using the Signal to Noise Ratio (SNR) Feature Screening Method and its associated SNR Saliency Measure for selecting a parsimonious set of salient features to classify pilot workload in addition to air traffic controller workload. Candidate features were derived …
Development Of An Operations Research Software Package For Army Divisions, Blane C. Wilson
Development Of An Operations Research Software Package For Army Divisions, Blane C. Wilson
Theses and Dissertations
There exists great potential for applying operations research techniques to solve specific problems in the areas of operations, installation support, and training at the Army division level. Because of the operational tempo of today's active-duty and reserve component units, command must focus on accomplishing the daily missions. Also, due their limited knowledge of the field, planners may not be aware of how operations research can be used to enhance planning and operations. Time, training funds, resources, safety, personnel, and equipment are all critical factors in this process. Operations research techniques could be used to improve division-level operations by saving time, …
The Application Of Statistical Sampling Techniques To The Operational Readiness Inspection, Troy L. Dixon, Timothy S. Madgett
The Application Of Statistical Sampling Techniques To The Operational Readiness Inspection, Troy L. Dixon, Timothy S. Madgett
Theses and Dissertations
A Blue Ribbon Commission report to the Air Force Chief of Staff in February 1997 makes several specific recommendations on the conduct of Operational Readiness Inspections. This thesis develops a solution to one of the recommendations of that report; utilize scientifically based sampling techniques to reduce the footprint of the inspection on an evaluated unit. Acceptance sampling, common in industry, is developed for use in the environment of the Operational Readiness Inspection. The time saved from this more efficient sampling practice reduces Inspector General time at an evaluation, decreases the footprint, and answers the specific recommendations of the Blue Ribbon …
An Advanced Visualization Method For An Operations Research Analysis, Steven C. Oimoen
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 …
Verification And Validation Of Faarr Model And Data Envelopment Analysis Models For United States Army Recruiting, Gene M. Piskator
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 …
Analysis Of Alternatives: Multivariate Considerations, John J. Siegner
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. …
The Application Of Sequential Convex Programming To Large-Scale Structural Optimization Problems, Todd A. Sriver
The Application Of Sequential Convex Programming To Large-Scale Structural Optimization Problems, Todd A. Sriver
Theses and Dissertations
Structural design problems are often modeled using finite element methods. Such models are often characterized by constraint functions that are not explicitly defined in terms of the design variables. These functions are typically evaluated through numerical finite element analysis (FEA). Optimizing large-scale structural design models requires computationally expensive FEAs to obtain function and gradient values. An optimization approach which uses the SCP sequential convex programming algorithm of Zillober, integrated as the optimizer in the Automated Structural Optimization System (ASTROS), is tested. The traditional approach forms an explicitly defined approximate subproblem at each design iteration that is solved using the method …
Using Bayesian Statistics In Operational Testing, Thuan H. Tran
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 …
Anderson-Darling And Cramer-Von Mises Based Goodness-Of-Fit Tests For The Weibull Distribution With Known Shape Using Normalized Spacings, Eric W. Frisco
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 …
A Value Focused Thinking Approach To Academic Course Scheduling, Shane A. Knighton
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 …
A Network Disruption Modeling Tool, James A. Leinart
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 …
Cross-Resolution Combat Model Calibration Using Bootstrap Sampling, Bryan S. Livergood
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 …
Application Of Decision Analysis To Evaluate Alternative Research And Development Investments, Michael J. Artelli
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. …
Forecasting Market Index Performance Using Population Demographics, Bradley J. Alden
Forecasting Market Index Performance Using Population Demographics, Bradley J. Alden
Theses and Dissertations
This study attempted to verify claims made by forecaster Harry S. Dent, Jr. It utilized regression analysis in order to determine the correlation between the number of births and the closings on a market index with a specified lag between the input and output variables. While the research was able to develop a model with the factor Dent considers the most important, the predictions based on this model did not completely coincide with the forecasts Dent makes. Furthermore, the research could not confirm the accentuation Dent places on a 46-year lag between predictor and response variables. As an extension, scenarios …
Parameter Estimation Of The Mixed Generalized Gamma Distribution Using Maximum Likelihood Estimation And Minimum Distance Estimation, Dean G. Boerrigter
Parameter Estimation Of The Mixed Generalized Gamma Distribution Using Maximum Likelihood Estimation And Minimum Distance Estimation, Dean G. Boerrigter
Theses and Dissertations
The Generalized Gamma is an extremely flexible distribution that is useful for reliability modeling. Among its many special cases are the Weibull and Exponential distributions. A mixture of Generalized Gamma Distributions is even more useful because multiple causes of failure can he simultaneously modeled. This research studied parameter estimation of the special cases of the Mixed Generalized Gamma Distribution and built upon them until the full nine-parameter distribution was being estimated. First, special cases of a single Generalized Gamma Distribution were estimated. Next, mixtures of Exponential distributions with both known and unknown location parameters were estimated. Next, mixtures of Weibull …
Calculating A Value For Dominant Battlespace Awareness, Eric A. Beene
Calculating A Value For Dominant Battlespace Awareness, Eric A. Beene
Theses and Dissertations
In times of ever-tightening military budgets, methodologies are required that can compare the contributions of various systems involved in the warfighting process. While many tools are in use that directly measure the effects of greater numbers of enhanced hardware, and even improved processes, no validated methodology exists to measure elements that contribute to Command, Control, Communications, and Computers (C4); Intelligence, Surveillance, and Reconnaissance (ISR); or to analytically compare these elements with more traditional hardware. This thesis develops a methodology for mathematically quantifying awareness in a military command and control (C2) environment. This methodology begins with the Observe-Orient-Decide-Act Loop to show …
Solving Geometric Knapsack Problems Using Tabu Search Heuristics, Christopher A. Chocolaad
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.
A New Sequential Goodness Of Fit Test For The Three-Parameter Weibull Distribution With Known Shape Based On Skewness And Kurtosis, Jonathan C. Clough
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 …
An Airlift Hub-And-Spoke Location-Routing Model With Time Windows: Case Study Of The Conus-To-Korea Airlift Problem, David W. Cox
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 …
A Life Cycle Cost Model For Innovative Remediation Technologies, Osman S. Dereli
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 …
Scheduling And Sequencing Arrivals To A Stochastic Service System, Peter M. Vanden Bosch
Scheduling And Sequencing Arrivals To A Stochastic Service System, Peter M. Vanden Bosch
Theses and Dissertations
Optimization of scheduled arrival times to an appointment system is approached from the perspectives of both queueing and scheduling theory. The appointment system is modeled as a one-server, first-come-first-served, transient queue with independent, distinctly distributed service times and no-show rates. If a customer does show, it is assumed to be punctual. The cost of operating the appointment system is a convex combination of customers' waiting times and the server's overtime. While techniques for finding the optimal static and dynamic schedules of arrivals have been proposed by other researchers, they mainly have focused on identical customers and strictly punctual arrivals. This …
Sensitivity Analysis Of A Combat Simulation Using Response Surface Methodology, William J. Berg
Sensitivity Analysis Of A Combat Simulation Using Response Surface Methodology, William J. Berg
Theses and Dissertations
This thesis provides a methodology to analyze the sensitivity of a combat simulation relative to the capabilities of the modeled weapon systems. Response Surface Methodology (RSM) was the primary technique used for analysis. A ground battle scenario was developed with a commercial PC wargame Empire II: The Art of War(TM). In the computer verses computer mode, the wargame was transformed into a combat simulation'. A screening experiment was used to determine which of an original 23 weapon factors were actually significant to this scenario. After analyzing the remaining five factors, only three ended up as truly significant to the battle …