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Operations Research, Systems Engineering and Industrial Engineering Commons™

Open Access. Powered by Scholars. Published by Universities.®

Operational Research

Air Force Institute of Technology

2007

Articles 1 - 15 of 15

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

Search Techniques For Multi-Objective Optimization Of Mixed Variable Systems Having Stochastic Responses, Jennifer G. Walston Sep 2007

Search Techniques For Multi-Objective Optimization Of Mixed Variable Systems Having Stochastic Responses, Jennifer G. Walston

Theses and Dissertations

A research approach is presented for solving stochastic, multi-objective optimization problems. First, the class of mesh adaptive direct search (MADS) algorithms for nonlinearly constrained optimization is extended to mixed variable problems. The resulting algorithm, MV-MADS, is then extended to stochastic problems (MVMADS-RS), via a ranking and selection procedure. Finally, a two-stage method is developed that combines the generalized pattern search/ranking and selection (MGPS-RS) algorithms for single-objective, mixed variable, stochastic problems with a multi-objective approach that makes use of interactive techniques for the specification of aspiration and reservation levels, scalarization functions, and multi-objective ranking and selection. A convergence analysis for the …

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Unreliable Retrial Queues In A Random Environment, James D. Cordeiro Jr. Sep 2007

Unreliable Retrial Queues In A Random Environment, James D. Cordeiro Jr.

Theses and Dissertations

This dissertation investigates stability conditions and approximate steady-state performance measures for unreliable, single-server retrial queues operating in a randomly evolving environment. In such systems, arriving customers that find the server busy or failed join a retrial queue from which they attempt to regain access to the server at random intervals. Such models are useful for the performance evaluation of communications and computer networks which are characterized by time-varying arrival, service and failure rates. To model this time-varying behavior, we study systems whose parameters are modulated by a finite Markov process. Two distinct cases are analyzed. The first considers systems with …

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Optimizing Distribution Sensor Placement For Border Patrol Interdiction Using Microsoft Excel, Adrian C. Patrascu Jun 2007

Optimizing Distribution Sensor Placement For Border Patrol Interdiction Using Microsoft Excel, Adrian C. Patrascu

Theses and Dissertations

The purpose of this research was to develop an electronic sensor placement model for border security. A model was developed using Microsoft Excel, with some add-on capabilities, to optimize the placement of electronic sensors on a border network given a pre-determined budgetary constraint. The model is capable of handling multiple sensor types, which are placed together as packages, and allows for daytime, nighttime, or 24 hour operation of each sensor type. Additionally, each sensor can be assigned a specific range and detection probability curve within the given range. The model is capable of optimizing either average coverage, or minimum coverage, …

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Analysis Of Army Transformation And The Effects On Customer Ordering Behavior, Joseph M. Colacicco Jun 2007

Analysis Of Army Transformation And The Effects On Customer Ordering Behavior, Joseph M. Colacicco

Theses and Dissertations

The United States Army began a major force transformation in 2003, which required a significant shift in logistics support constructs. This thesis provides an in-process review of the effects of the current transformation efforts on supply effectiveness and attempts to determine factors that influence customer ordering behavior. Specifically, the thesis sought to answer three subproblems addressing the effect of transformation on supply effectiveness, the correlation of supply effectiveness metrics to customer ordering behavior, and other potential sources of variance in ordering behavior. The subproblems were answered through an examination of the supply document histories of two Brigades, one legacy Brigade …

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A Layered Social And Operational Network Analysis, Jennifer L. Geffre Mar 2007

A Layered Social And Operational Network Analysis, Jennifer L. Geffre

Theses and Dissertations

To provide maximal disruption to a clandestine/terrorist network's ability to conduct missions, we must develop a means to determine the individuals' importance to the network and operations. In a network centric world, this importance is represented as an additive value of their criticality across the convergence of multiple layers of network connections. The connections layers of the network are comprised of social layers (Acquaintance, Friendship, Nuclear Family, Relatives, Student-Teacher, and Religious Mentors, Reverent Power and others), as well as layers representing interactions involving Resources, Knowledge/Skills and Temporal Local. The social criticality of an individual is measured by centrality. Event Trees …

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A Multivariate Magnitude Robust Control Chart For Mean Shift Detection And Change Point Estimation, Ryan M. Harrell Mar 2007

A Multivariate Magnitude Robust Control Chart For Mean Shift Detection And Change Point Estimation, Ryan M. Harrell

Theses and Dissertations

Statistical control charts are often used to detect a change in an otherwise stable process. This process may contain several variables affecting process stability. The goal of any control chart is to detect an out-of-control state quickly and provide insight on when the process actually changed. This reduces the off-line time the quality engineer spends assigning causality. In this research, a multivariate magnitude robust chart (MMRC) was developed using a change point model and a likelihood-ratio approach. Here the process is considered in-control until one or more normally distributed process variables permanently and suddenly shifts to out-of-control, stable value. Using …

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Improved Hyperspectral Image Testing Using Synthetic Imagery And Factorial Designed Experiments, Joseph P. Bellucci Mar 2007

Improved Hyperspectral Image Testing Using Synthetic Imagery And Factorial Designed Experiments, Joseph P. Bellucci

Theses and Dissertations

The goal of any remote sensing system is to gather data about the geography it is imaging. In order to gain knowledge of the earth's landscape, post-processing algorithms are developed to extract information from the collected data. The algorithms can be intended to classify the various ground covers in a scene, identify specific targets of interest, or detect anomalies in an image. After the design of an algorithm comes the difficult task of testing and evaluating its performance. Traditionally, algorithms are tested using sets of extensively ground truthed test images. However, the lack of well characterized test data sets and …

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Mathematical Programming Model For Fighter Training Squadron Pilot Scheduling, Thomas M. Newlon Mar 2007

Mathematical Programming Model For Fighter Training Squadron Pilot Scheduling, Thomas M. Newlon

Theses and Dissertations

The United States Air Force fighter training squadrons build weekly schedules using a long and tedious process. Very little of this process is automated and optimality of any kind is nearly impossible. Schedules are built to a feasible condition only to be changed with consideration of Wing level requirements. Weekly flying schedules are restricted by requirements for crew rest, days since a pilot's last sortie, sorties in the last 30 days, and sorties in the last 90 days. By providing a scheduling model to the pilot charged with creating the schedule, valuable pilot hours could be spent in the cockpit, …

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Change-Point Methods For Overdispersed Count Data, Brian A. Wilken Mar 2007

Change-Point Methods For Overdispersed Count Data, Brian A. Wilken

Theses and Dissertations

A control chart is often used to detect a change in a process. Following a control chart signal, knowledge of the time and magnitude of the change would simplify the search for and identification of the assignable cause. In this research, emphasis is placed on count processes where overdispersion has occurred. Overdispersion is common in practice and occurs when the observed variance is larger than the theoretical variance of the assumed model. Although the Poisson model is often used to model count data, the two-parameter gamma-Poisson mixture parameterization of the negative binomial distribution is often a more adequate model for …

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Planning And Assessing Stability Operations: A Proposed Value-Focused Thinking Approach, Gerald D. Fensterer Mar 2007

Planning And Assessing Stability Operations: A Proposed Value-Focused Thinking Approach, Gerald D. Fensterer

Theses and Dissertations

Stability operations are vital to establish peace in the aftermath of conflict. The United States is often called in for military support during conflict. The new American military paradigms include establishing peace through stability operations after a military conflict. Due to this new role, military decision makers face many difficulties in conducting successful stability operations. Compounding this problem is the limited number of resources pertaining to stability operations: experts, doctrine, knowledge, and technology. Two overarching challenges of stability operations facing decision makers are planning and prioritizing of stability operations and determining progress. This thesis applies a structured analytical approach to …

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Critical Infrastructure Rebuild Prioritization Using Simulation Optimization, Namsuk Cho Mar 2007

Critical Infrastructure Rebuild Prioritization Using Simulation Optimization, Namsuk Cho

Theses and Dissertations

This thesis examines the importance of a critical infrastructure rebuild strategy following a terrorist attack or natural disaster such as Hurricane Katrina. Critical infrastructures are very complex and dependent systems in which their re-establishment is an essential part of the rebuilding process. A rebuild simulation model consisting of three layers (physical, information, and spatial) captures the dependency between the six critical infrastructures modeled. We employ a simulation optimization approach to evaluate rebuild prioritization combinations with a goal of minimizing the time needed to achieve an acceptable rebuild level. We use a simulated annealing heuristic as an optimization technique that works …

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Approximate Analysis Of An Unreliable M/M/2 Retrial Queue, Brian P. Crawford Mar 2007

Approximate Analysis Of An Unreliable M/M/2 Retrial Queue, Brian P. Crawford

Theses and Dissertations

This thesis considers the performance evaluation of an M/M/2 retrial queue for which both servers are subject to active and idle breakdowns. Customers may abandon service requests if they are blocked from service upon arrival, or if their service is interrupted by a server failure. Customers choosing to remain in the system enter a retrial orbit for a random amount of time before attempting to re-access an available server. We assume that each server has its own dedicated repair person, and repairs begin immediately following a failure. Interfailure times, repair times and times between retrials are exponentially distributed, and all …

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An Efficient Metaheuristic For Dynamic Network Design And Message Routing, Robert B. Hartlage Mar 2007

An Efficient Metaheuristic For Dynamic Network Design And Message Routing, Robert B. Hartlage

Theses and Dissertations

The implementation of Net-centric warfare presents major challenges in terms of effectively and efficiently delivering critical information across the Global Information Grid. In many cases, the amount of information requested will exceed the capabilities of the network. One challenge is to dynamically design the network (assign transceivers) to maximize the amount of required information that can be transmitted and the quality of service for those transmissions - to best implement the communications tasking order. The problem is as follows: given a list of required message traffic, to include source, destination, size, and priority, design the network to maximize the delivery …

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Updating Optimal Decisions Using Game Theory And Exploring Risk Behavior Through Response Surface Methodology, Jeremy D. Jordan Mar 2007

Updating Optimal Decisions Using Game Theory And Exploring Risk Behavior Through Response Surface Methodology, Jeremy D. Jordan

Theses and Dissertations

This thesis utilizes game theory within a framework for updating optimal decisions based on new information as it becomes available. Methodology is developed that allows a decision maker to change his perceived optimal policy based on available knowledge of the opponents strategy, where the opponent is a rational decision maker or a random component nature. Utility theory is applied to account for the different risk preferences of the decision makers. Furthermore, response surface methodology is used to explore good risk strategies for the decision maker to approach each situation with. The techniques are applied to a combat scenario, a football …

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Examining Clandestine Social Networks For The Presence Of Non-Random Structure, Joshua S. Seder Mar 2007

Examining Clandestine Social Networks For The Presence Of Non-Random Structure, Joshua S. Seder

Theses and Dissertations

This thesis develops a tractable, statistically sound hypothesis testing framework for the detection, characterization, and estimation of non-random structure in clandestine social networks. Network structure is studied via an observed adjacency matrix, which is assumed to be subject to sampling variability. The vertex set of the network is partitioned into k mutually exclusive and collectively exhaustive subsets, based on available exogenous nodal attribute information. The proposed hypothesis testing framework is employed to statistically quantify a given partition's relativity in explaining the variability in the observed adjacency matrix relative to what can be explained by chance. As a result, valuable insight …

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