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Operational Research

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Articles 1951 - 1980 of 2158

Full-Text Articles in Operations Research, Systems Engineering and Industrial Engineering

Forecasting And Explanatory Models For Middle Eastern Defense Budgets: A Case Study Of Saudi Arabia, Robert S. Renfro Ii Mar 1996

Forecasting And Explanatory Models For Middle Eastern Defense Budgets: A Case Study Of Saudi Arabia, Robert S. Renfro Ii

Theses and Dissertations

This thesis focuses on means of forecasting Saudi Arabian military expenditures and the effect of such expenditures on the United States. Saudi Arabia is one of the largest purchasers of American arms and will continue to be for many years. Saudi Arabia has experienced several recent changes in economic and government policy. Using exponential smoothing techniques and linear regression, we isolated several trends in Saudi Arabian military expenditures. Using two linear regression models, military expenditures were then forecast with excellent results. The first model considered the assumption that Gulf War spending would continue. This model uses Saudi Arabian Gross Domestic …

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Performance Study Of Shared Versus Nonshared Bandwidth On A Packet-Switched Network, John P. Stevens Mar 1996

Performance Study Of Shared Versus Nonshared Bandwidth On A Packet-Switched Network, John P. Stevens

Theses and Dissertations

In wide area computer data communications, many networks have evolved by satisfying increased user demands in the most expedient manner. In some cases, new users’ demands are satisfied by installing a new link, rather than sharing the links that are already in place. This research investigates the differences in performance between using a dedicated link for each source destination pair (nonshared bandwidth) and using a single link to be used by all source destination pairs (shared bandwidth). Simulation models are developed for a wide area network using shared bandwidth, and a wide area network using nonshared bandwidth. The quality of …

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Modeling Mobility Engineering In A Theater Level Combat Model, Brian K. Hobson Mar 1996

Modeling Mobility Engineering In A Theater Level Combat Model, Brian K. Hobson

Theses and Dissertations

This thesis describes the development of a methodology to model theater-level mobility engineering assets in the Joint Staff's Joint Warfare Analysis Experimental Prototype (JWAEP) and to quantify the joint and Army doctrine that guides the task organization of engineers for combat and which quantifies engineer mobility effects in combat. The methodology incorporates theater-level mobility engineering assets into the JWAEP by using Mission, Enemy, Troops available, Terrain, and Time (MET-T principles which reflect joint and Army doctrine, and combines them with the existing basic concepts in other theater-level models. Additional aspects of the problem include determining the manmade and natural obstacles' …

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Measuring The Impact Of Programmed Depot Maintenance Funding Shortfalls On Weapon System Availability, Donald F. Hurry Mar 1996

Measuring The Impact Of Programmed Depot Maintenance Funding Shortfalls On Weapon System Availability, Donald F. Hurry

Theses and Dissertations

This study used the Poisson regression technique, bootstrap estimates, and the Kaplan-Meier estimates for survivor curves to determine the impact of Programmed Depot Maintenance (PDM) on weapon system availability. More specifically, these techniques estimated the effect in the number failures per year due to PDM, but the bootstrap technique also estimated the effect in the amount of downtime experienced by a weapon system due to PDM. Although the Poisson regression model did not pass the rigors of statistical testing, the Poisson regression suggested differences in the number of failures per year between PDM and no-PDM weapon systems. The results of …

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Procedures For Testing Deterministic Scheduling Models: A Dakota Case Study, Keith H. Mccready Mar 1996

Procedures For Testing Deterministic Scheduling Models: A Dakota Case Study, Keith H. Mccready

Theses and Dissertations

The DAKOTA scheduling system has been proposed for use in the United States Air Forces Europe's (USAFE's) Operational Support Airlift (OSA) scheduling. This thesis examines the OSA scheduling topic and reviews the relevant literature on vehicle routing, concluding that exact methods are intractable for large problem sizes. Consequently, heuristic methods must be considered. This thesis takes a detailed look at the DAKOTA heuristic. It examines the concepts of Validation, Verification and Accreditation (VV&A), particularly as they apply to heuristics and algorithms. It then defines what measures of performance may prove useful in judging heuristics and algorithms in general, and details …

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A Methodology To Assess The Air Force Materiel Command's Exercise Support Program's Weighting Scheme, Gilbert D. Ness Mar 1996

A Methodology To Assess The Air Force Materiel Command's Exercise Support Program's Weighting Scheme, Gilbert D. Ness

Theses and Dissertations

This research performs analysis on the Air Force Materiel Command's Exercise Support Program's Weighting Scheme so that decision makers can create a more efficient and effective Resource Allocation - Integrated Process Team (RA-IPT) manpower allocation process. A linear programming (LP) model was derived from the Exercise Support Program (ESP) to assign manpower reductions throughout the Mission Element Board (MEB) organizational level in AFMC. Parametric analysis was performed on the LP model by simultaneously changing multiple objective function coefficients with the use of various direction vectors. These direction vectors were applied with the use of an incrementally increasing scalar step size …

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Development Of A Decision Support System For The Department Of Energy's Selection Of Waste Site Remediation Technologies, Brian E. Ralston Mar 1996

Development Of A Decision Support System For The Department Of Energy's Selection Of Waste Site Remediation Technologies, Brian E. Ralston

Theses and Dissertations

The Department of Energy is faced with the complex decision of selecting technologies for waste site remediation. This research focused on developing a decision support system to aid the decision maker in selecting the best strategy of remediation technologies. A decision analysis model was developed which incorporates life cycle cost data, risk information, and user input, to analyze the technology choices. The research outlined the use of multiple attribute utility theory using exponential attribute utility functions with a simple additive objective function. The best available data was used to demonstrate the capabilities of the model. The model provides the decision …

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Statistical Process Control And Medical Surveillance. An Application With Liver Function Tests, Bryan D. Richardson Mar 1996

Statistical Process Control And Medical Surveillance. An Application With Liver Function Tests, Bryan D. Richardson

Theses and Dissertations

Traditionally, medical surveillance of liver disease generally involves a battery of tests. This research used multivariate analysis techniques to reduce the number of measures required to identify liver dysfunction and found using a Transferase Index (a combination of three tests; ALT, AST, and GGT) provided the most satisfying assessment, but the single best indicator, ALT, may be sufficient. Transferase Index and ALT criterion were both applied to SPC control charts. Through the use of statistical process control (SPC), this research identified work zones possessing signs of adverse effects to an individual's liver as a possible result of their work environment …

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An Investigation Of Preliminary Feature Screening Using Signal-To-Noise Ratios, David B. Sumrell Mar 1996

An Investigation Of Preliminary Feature Screening Using Signal-To-Noise Ratios, David B. Sumrell

Theses and Dissertations

A new saliency metric and a new saliency screening method are developed. This new metric, the SN saliency metric, is based upon signal-to-noise ratios, where the signal is provided by a sum of squared weights associated with a given feature, and the noise is based upon a sum of squared weights associated with a reference noise feature which is injected into the data. The resultant metric allows for a direct comparison of the feature of interest with a reference noise feature which is known to be nonsalient. The SN saliency screening method, which uses the SN saliency metric, offers the …

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A Response Surface Methodology Approach To Groundwater Model Calibration, Jeffrey B. Rowland Mar 1996

A Response Surface Methodology Approach To Groundwater Model Calibration, Jeffrey B. Rowland

Theses and Dissertations

This thesis examined the effect of parameter bounding, a reduced data set, and data enrichment techniques on a response surface methodology (RSM) approach to groundwater model calibration. The four phases of the study included a calibration using a very dense data matrix, a calibration using a sparse calibration matrix, an evaluation of several data enrichment techniques, and a calibration using a data matrix enlarged with the use of the best enrichment technique. All calibrations were conducted using only a first order approximation to the response surface and with bounds placed on the input parameters. The first two calibrations using the …

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Optimization Analysis For Design And Planning Of Multi-Project Programs, Victor D. Wiley Mar 1996

Optimization Analysis For Design And Planning Of Multi-Project Programs, Victor D. Wiley

Theses and Dissertations

Program Management concerns the long-term planning, coordination, and control of major technological, engineering, scientific, and/or developmental activities. In general, programs tend to be exceptionally large, consisting of several parallel or sequential projects or groups of projects. While many of the approaches developed for projects have been used in program management, there are critical differences between programs and projects. A key difference is the magnitude of programs, both in program duration and number of tasks to be coordinated. In addition, project parameters are driven by program decisions. While a large number of modeling efforts have focused at the project level, very …

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Applying Response Surface Methodology To Readiness-Based Leveling Of Reparable Items, Todd E. May Mar 1996

Applying Response Surface Methodology To Readiness-Based Leveling Of Reparable Items, Todd E. May

Theses and Dissertations

Reparable items play a large role in determining the readiness of United States Air Force weapon systems. Many factors characterizing flying tempo and item repair and transit time influence the level of fleet readiness. Readiness-Based Leveling (RBL) considers these factors as it seeks to maximize aircraft readiness as it allocates spare reparable items between bases and a depot. The purpose of this research was to demonstrate the validity of using response surface methodology (RSM) within the context of RBL in an effort to quantify the influences these factors have on aircraft readiness. RSM applied designed experiments and least squares regressions …

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Statistical Process Control In Medical Surveillance. An Application Using Spirometry, Paul W. Mcaree Mar 1996

Statistical Process Control In Medical Surveillance. An Application Using Spirometry, Paul W. Mcaree

Theses and Dissertations

This research effort concentrated on applying statistical process control techniques to the results of seven years worth of spirometry exams of workers at Wright-Patterson AFB in helping the occupational health squadron identify potential work hazard areas. Each spirometry exam was classified as abnormal or normal based on a comparison with established normals or a significant loss of function from the previous year's exam for the individual. Each test was classified into the work area of the individual and the number of abnormalities per population of the work area was examined.

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Surveillance Plan For Monitoring The Shelf-Life Of Chemical Defense Coveralls, Robert E. Neher Jr. Mar 1996

Surveillance Plan For Monitoring The Shelf-Life Of Chemical Defense Coveralls, Robert E. Neher Jr.

Theses and Dissertations

This thesis found a surveillance plan to be used to monitor the shelf-life of the Air Force's chemical defense coveralls. The sampling tests are destructive and the objective was to find a surveillance plan that would minimize the number of suits sampled yet provide enough information to accurately determine if the chemical defense coveralls had degraded past a minimum acceptable level. Six sampling plans were developed and analyzed. The sampling plans included the Air Force's original fixed sampling plan, several variations of sequential sampling plans, a Bayesian sampling plan, and an ad hoc pre-posturing plan. Each of the sampling plans …

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A Decision Support Model For Large Systems Using Quality Function Deployment And Goal Programming: A Capital Budgeting Problem, Kenneth Lindsey Jr. Jan 1996

A Decision Support Model For Large Systems Using Quality Function Deployment And Goal Programming: A Capital Budgeting Problem, Kenneth Lindsey Jr.

Engineering Management & Systems Engineering Theses & Dissertations

Effective planning for the modernization of U.S. Air Force fighter aircraft requires a perception of the future tasks these aircraft will be called upon to perform, and the improvements and modifications that will be required to successfully accomplish those tasks. A great deal of research has been done in the areas of military strategy, quality function deployment, capital budgeting, and goal programming, as separate areas of study. This thesis details the research and analysis performed for a project called The Fighter Configuration Plan (FICOP), in which these areas were integrated in a decision support model to aid the Air Force …

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Dynamic Scale Genetic Algorithm: An Enhanced Genetic Search For Discrete Optimization, Bela Dange Joshi Jan 1996

Dynamic Scale Genetic Algorithm: An Enhanced Genetic Search For Discrete Optimization, Bela Dange Joshi

Engineering Management & Systems Engineering Theses & Dissertations

The minimization of operations and support resources of reusable launch vehicles is a complex task, involving discrete optimization and the simulation domain. Genetic algorithms, offering a robust search strategy suitable for integer variables and the simulation domain, can be applied to minimize these resources. This research developed an enhanced genetic algorithm for problems with a linear objective function, the most common class of discrete optimization problems. The dynamic scale genetic algorithm developed here incorporates concepts of implicit enumeration to enhance search. This is achieved by utilizing problem specific information to refine the solution space over successive generations. The utility of …

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Issues And Challenges In Validating Military Simulation Models, Michael R. Elmer Jan 1996

Issues And Challenges In Validating Military Simulation Models, Michael R. Elmer

Theses and Dissertations

The purpose of this thesis is to address the challenges of validating simulation models, especially those challenges facing military simulation analysts. Three distinct issues are of concern to the military simulation analyst: (1) What type of validation effort do the academic experts recommend? (2) What does the military policy say is necessary for a proper validation effort? (3) What can a simulation practitioner realistically accomplish given time and resource constraints? Four methodologies were chosen to represent the academic perspective on validation. A model of validation methods is integrated from the methodologies of these four simulation validation references. The validation policies …

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Cycle Time Estimation For Simulating A Tandem Queueing Systems Using Aggregation Techniques, Paul Savory, Gerald Mackulak Jan 1996

Cycle Time Estimation For Simulating A Tandem Queueing Systems Using Aggregation Techniques, Paul Savory, Gerald Mackulak

Department of Industrial and Management Systems Engineering: Faculty Publications

One approach to simulating a single-server tandem queuing system is to explicitly model each of the production stages. In this paper, we apply queueing theory, a recursive algorithm, and composite random number sampling to develop an equivalent aggregate representation consisting of only a single production stage. Preliminary test results indicate that the aggregation works well for estimating the mean and variability of the total cycle time.

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Validation Of Operational Multiscale Environment Model With Grid Adaptivity (Omega), Gordon R. Taylor Dec 1995

Validation Of Operational Multiscale Environment Model With Grid Adaptivity (Omega), Gordon R. Taylor

Theses and Dissertations

The Defense Nuclear Agency (DNA) is improving the military's capability to forecast dosage and hazard levels due to release of chemical, biological, and nuclear agents. During Operation DESERT STORM the military realized the need for models to predict risk levels for military personnel assigned proximate to missile attacks. One project associated with this is the continuing development of the Operational Multiscale Environmental Model with Grid Adaptivity (OMEGA). DNA has sponsored AFIT to validate OMEGA with focus on incorporating weather data obtained from Air Force Combat Climatology Center for the period of the Chernobyl Nuclear Accident. The physics of the model …

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Decision Support Model For Municipal Solid Waste Management At Department Of Defense Installations, John F. Muratore Dec 1995

Decision Support Model For Municipal Solid Waste Management At Department Of Defense Installations, John F. Muratore

Theses and Dissertations

This research focuses on the development of a decision support model to identify the preferred strategy for managing municipal solid waste using the principles of decision analysis theory. The model provides an effective decision making tool to evaluate and compare different municipal solid waste management strategies. The users of this model, the Environmental Manager or decision maker at a given installation, can enter installation-specific waste stream characteristics, treatment and disposal costs, and material buy-back prices to determine the expected value for various alternative strategies. The strategy having the greatest expected value is considered the preferred alternative. In calculating the expected …

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Using Mathematica To Aid Simulation Analysis, Paul Savory Dec 1995

Using Mathematica To Aid Simulation Analysis, Paul Savory

Department of Industrial and Management Systems Engineering: Faculty Publications

As computer power has increased, so has the capability of software developers to write programs that assist people with time-consuming tasks. Mathematica is such a program. The objective of this paper is to demonstrate how Mathematica, a symbolic programming environment, can be used to aid simulation analysis. In addition to a general discussion of Mathematica’s uses, advantages, and disadvantages, several examples will be presented. The examples include using Mathematica for distribution fitting, queueing analysis, random number generation, and creating a surface plot for optimization.

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System Dynamic Modeling Of Activity And Flow Relationships In Plant Layout Problems, Gary Allen Weaver Oct 1995

System Dynamic Modeling Of Activity And Flow Relationships In Plant Layout Problems, Gary Allen Weaver

Engineering Management & Systems Engineering Theses & Dissertations

The problem of determining an optimal plant layout involves the distribution of machinery, service areas, and storage spaces. The solution is usually determined for a specific period of time and static in nature. Planning for the plant layout is normally performed at the onset of new construction, or major refurbishment of an existing facility. In addition, plant layouts are renewed when a significant productivity decrease is experienced over long periods of time and linked to material flow problems, and when an expanding company plans for major capital expenditures in equipment and space. Due to the dynamic nature of business the …

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Methods For Monitoring Process Control And Capability In The Presence Of Autocorrelation, Daniel J. Zalewski Aug 1995

Methods For Monitoring Process Control And Capability In The Presence Of Autocorrelation, Daniel J. Zalewski

Theses and Dissertations

When standard control charts are applied to a process whose measurements of quality exhibit autocorrelation, the performance of those charts can be considerably different than that expected when no autocorrelation is present. To model this performance, the existing definitions of assignable and chance causes of variation are extended to account for the variation induced by the autocorrelation structure. The application of statistical thinking toward continuous process improvement using the proposed taxonomy is discussed. A method to select control limits which yield a specified average run length in the absence of assignable causes of variation and which is suitable for use …

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A Robust Method Of Solving Nonlinear Boundary Value Problems Via Modified Compromise Programming, John L. Zornick May 1995

A Robust Method Of Solving Nonlinear Boundary Value Problems Via Modified Compromise Programming, John L. Zornick

Theses and Dissertations

This study is an extension of Ng's previous work in which goal programming was used to determine an approximate solution to a boundary value problem. This approach follows the same basic approach developed by Ng in which the method of collocation was recast as a compromise programming model. Hence, instead of solving a system of simultaneous nonlinear equations, one seeks a compromise solution which minimizes (in a weighted residual sense) a vector norm of the differential equation residuals. A difference in this approach is that it makes use of a genetic algorithm as the optimizing engine as opposed to the …

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Predicting Utility Bills For Air Combat Command A Study Of Forecasting Techniques, William L. Luthie Apr 1995

Predicting Utility Bills For Air Combat Command A Study Of Forecasting Techniques, William L. Luthie

Engineering Management & Systems Engineering Theses & Dissertations

Many companies use forecasting techniques as a tool in managing their assets. Trends in such items as sales, population and inventory levels have all been determined at one time or another using forecasting, yet research indicates that these tools have not been utilized to predict utility budgets. This research was conducted to determine if such techniques could be applied to the specific task of predicting the utility bill at an Air Force base. Three quantitative models were chosen, the Moving Average, Exponential Smoothing and Regression, to determine their applicability to the task at hand. One base within Air Combat Command, …

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Selecting Optimal Experiments For Feedforward Multilayer Perceptrons, Lisa M. Belue Mar 1995

Selecting Optimal Experiments For Feedforward Multilayer Perceptrons, Lisa M. Belue

Theses and Dissertations

Where should a researcher conduct experiments to provide training data for a multilayer perceptron? This question is investigated and a statistically-based method for optimally selecting experimental design points for multilayer perceptrons is introduced. Specifically, a criterion is developed based on the size of an estimated confidence ellipsoid for the weights in the multilayer perceptron. This criterion is minimized over a set of exemplars to find optimal design points. Initially, single output networks are examined. An example is used to demonstrate the superiority of optimally selected design points over randomly chosen points and points chosen in a grid pattern. Also, two …

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Life-Cycle Cost Analysis For Radioactive Waste Remediation Alternatives, Thomas P. White, Ronald J. Toland, Dorian Y. Buitrago Mar 1995

Life-Cycle Cost Analysis For Radioactive Waste Remediation Alternatives, Thomas P. White, Ronald J. Toland, Dorian Y. Buitrago

Theses and Dissertations

This research has two primary objectives. The first is to develop a generic, interactive, spreadsheet-based life-cycle cost model that uses net present value and risk analysis techniques for cost comparison. The second is to apply the model specifically to the vitrification and cementation methods of waste remediation. By using spreadsheet analysis and graphics capabilities, the model will provide direct and objective comparisons of remediation alternatives. Since vitrification is a new technology, the plant design and operations are conceptual. Therefore, computer simulation and engineering judgement are integral to the vitrification LCC estimate.

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Applications Of Statistical Process Control In Monitoring Aircrew Bombing Proficiency, Kirk G. Horton Mar 1995

Applications Of Statistical Process Control In Monitoring Aircrew Bombing Proficiency, Kirk G. Horton

Theses and Dissertations

The current tools used by squadron supervisors to monitor the bombing performance of aircrews flying F-111E aircraft are monthly reports that have little predictive capability. No real-time methodology exists for monitoring and predicting aircrew bombing performance and preventing bombing problems that might cause an individual to become unqualified. It has been suggested that Statistical process Control (SPC) can be applied to the bombing process to develop tools for managing the process, correcting problems, and improve the bombing performance of a squadron. This study investigates the application of SPC to the bombing process. It examines data taken from an F-111E Fighter …

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Patient-Aircraft Forecasting For The Strategic Aeromedical Evacuation "Lift-Bed Process", Donald F. Kimminau Mar 1995

Patient-Aircraft Forecasting For The Strategic Aeromedical Evacuation "Lift-Bed Process", Donald F. Kimminau

Theses and Dissertations

The goal of this research is to develop a tool for the Global Patient Movement Requirements Center (GPMRC) to efficiently forecast Aeromedical Evacuation (AE) aircraft and schedule patients in the lift-bed process. During a contingency, GPMRC is responsible for requesting required airlift, and providing lift-bed candidates to the Theater Patient Movement Requirements Center. The objective is to evacuate all waiting patients while minimizing the number of C-141 aircraft which must be dedicated to the AE mission. In the solution process, a short-term forecast of patient movement requirements is input, including number of patients, bed and aircraft availability, and hub preferences. …

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The Effect Of Repeatedly Sampling An Embedded Metamodel On The Simulation Response, John Kent Patterson Mar 1995

The Effect Of Repeatedly Sampling An Embedded Metamodel On The Simulation Response, John Kent Patterson

Theses and Dissertations

This study investigated the effect on simulation output of repeatedly sampling an embedded metamodel. A metamodel is said to be embedded within a simulation if it is used to replace a submodule of that simulation. Replacing a deterministic module with an embedded deterministic metamodel poses no apparent mathematical problems. However, using a deterministic metamodel to replace a stochastic simulation component could require additional corrective actions. This research was performed in two phases. The first phase dealt with a set of tandem queues. It was shown that as each queue was sequentially replaced with a metamodel, the total system variance was …

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