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Air Force Institute of Technology

Theses and Dissertations

2003

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Articles 31 - 60 of 102

Full-Text Articles in Engineering

Game Theory And U-Boats In The Bay Of Biscay, Joseph C. Price Mar 2003

Game Theory And U-Boats In The Bay Of Biscay, Joseph C. Price

Theses and Dissertations

Analysis of a large combat campaign using game theory is difficult due to non- linearities and other soft factors which exist in a complex system. However, game theory can give decision makers insight into strategies and outcomes that can be utilized to maximize one's objective. Agent-based simulation provides the means to model complex systems with non-linearities, by allowing for interactions among independent "agents." This thesis investigates game-theoretic strategies in agent-based simulation, modeled after the Allied search for U-boats in the Bay of Biscay during World War II (WWII). It also looks into the effects of adaptation on strategies by comparison …

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Modeling Homeland Security: A Value Focused Thinking Approach, Kristopher A. Pruitt Mar 2003

Modeling Homeland Security: A Value Focused Thinking Approach, Kristopher A. Pruitt

Theses and Dissertations

The events of September 11, 2001 have propelled the topic of homeland security to the forefront of national concern. The threat of terrorism within the United States has reached an unprecedented level. The pervasive vulnerabilities of the nation's critical infrastructure coupled with the destructive capabilities and deadly intentions of modern terrorists pose extraordinary risks. The United States must mitigate these risks while at the same time balancing the associated costs and impact on civil liberties. Currently, the United States lacks effective methods and measure for assessing the security of the homeland from acts of terrorism. This study outlines a first …

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A Simulation Based Comparative Analysis Of Alternatives For Tuition Assistance Organizational Structures, Tamiko L. Ritschel Mar 2003

A Simulation Based Comparative Analysis Of Alternatives For Tuition Assistance Organizational Structures, Tamiko L. Ritschel

Theses and Dissertations

The military services have experienced enormous downsizing efforts in the last decade. With these initiatives, organizations have had to derive innovative ways to meet their objectives with fewer resources. An organization's structure is an avenue to address these challenges within the atmosphere of a shrinking capital budget. Organizational structure changes can affect every aspect of the organization. Such an impact suggests proposals for drastic organizational changes must meet the rigors of a full analysis. The intent of this research is to provide a comprehensive analysis of centralization options for Air Force Tuition Assistance efforts. This thesis effort involves the development …

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A Stochastic Model For Joint Reception, Staging, Onward Movement, And Integration (Jrsoi), Nathan P. Sherman Mar 2003

A Stochastic Model For Joint Reception, Staging, Onward Movement, And Integration (Jrsoi), Nathan P. Sherman

Theses and Dissertations

A stochastic model for the performance evaluation of a key phase in the deployment process, namely Joint Reception, Staging, Onward Movement, and Integration (JRSOI) is presented. The process is modeled as an open, multi-class tandem queueing network wherein personnel and various classes of cargo are modeled as the flow entities and the stages of the process constitute individual queueing stations. Single and multiple-class models at both low and high resolutions are presented. No analytical stochastic model of this process currently exists in the literature or in practice. The model provides a quick look at key aggregate performance measures such as …

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Optimal Replacement Policies For Satellite Constellations, Bradley R. Sumter Mar 2003

Optimal Replacement Policies For Satellite Constellations, Bradley R. Sumter

Theses and Dissertations

This work considers the problem of finding optimal replacement policies that minimize the expected total cost of maintaining a satellite constellation. The problem is modeled using discrete-time Markov decision processes to determine the replacement policy by allowing the satellite constellation to be in one of a finite number of states at each decision epoch. The constellation stochastically transitions at each time step from one state to another as determined by a set of transition probabilities. At each decision epoch, a decision maker chooses an action from a set of allowable actions for the current system state. A cost associated with …

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Linear Programming And Genetic Algorithm Based Optimization For The Weighting Scheme Of A Value Focused Thinking Hierarchy, David M. Thawley Mar 2003

Linear Programming And Genetic Algorithm Based Optimization For The Weighting Scheme Of A Value Focused Thinking Hierarchy, David M. Thawley

Theses and Dissertations

Deriving weights for a Value Focused Thinking (VFT) hierarchy demands considerable time and input from Decision Makers (DM) and Subject Matter Experts (SME). Often, the DMs and SMEs are the leaders of companies and organizations, and this required time is unrealistic with their schedules. In these situations, as well as scenarios where there no available DMs/SMEs, conventional means of weighting a VFT hierarchy are impossible, and any VFT analysis is halted. When historical data exists on evaluation measures and performance of alternatives, linear programming and genetic algorithm based optimization may be used to derive historically optimal weights for a hierarchy. …

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Models For Sortie Generation With Autonomic Logistics, Nicholaus A. Yager Mar 2003

Models For Sortie Generation With Autonomic Logistics, Nicholaus A. Yager

Theses and Dissertations

The primary objective of this research is to investigate the impact of an autonomic logistics system (ALS) on the sortie generation process for an individual airbase. As in some prior studies of this process, the methodology used to model the sortie generation process is a queueing network containing fork-join nodes for concurrent maintenance activities. The sortie generation rate is commonly regarded as the primary performance measure of the sortie generation process. This measure coincides with the throughput and is used to compare two models: (1) pre-ALS operations and (2) ALS-enhanced airbase operations. Analysis of the models shows that the ALS …

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An Investigation Of The Effects Of Correlation In Sensor Fusion, Susan A. Storm Mar 2003

An Investigation Of The Effects Of Correlation In Sensor Fusion, Susan A. Storm

Theses and Dissertations

This thesis takes the first step towards the creation of a synthetic classifier fusion-testing environment. The effects of data correlation on three classifier fusion techniques were examined. The three fusion methods tested were the ISOC fusion method (Haspert, 2000), the ROC "Within" Fusion method (Oxley and Bauer, 2002) and the simple use of a Probabilistic Neural Network (PNN) as a fusion tool. Test situations were developed to allow the examination of various levels of correlation both between and within feature streams. The effects of training a fusion ensemble on a common dataset versus an independent data set were also contrasted. …

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Multimission Aircraft Design Study-Operational Scenarios, Nevin Coskuner Mar 2003

Multimission Aircraft Design Study-Operational Scenarios, Nevin Coskuner

Theses and Dissertations

In the most recent years, the Command, Control and Communications, Counter Measures, Intelligence, Surveillance and Reconnaissance (C3CMISR) aircrafts are used commonly in many NATO and UN Operations around the world. These aircrafts are AWACS, JSTARS, Rivet Joint, Compass Call and ABCCC. They provide close air support in the name of airborne surveillance, ground moving target surveillance, target reconnaissance, jamming, and command, control and communications issues in operational environments. Those aircrafts are tasked with a wide variety of missions than ever before in operational theaters and each one of them comprises a specific amount of cost and risk factors. As a …

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Multimission Aircraft Design Study, Payload, Ahmet Kahraman Mar 2003

Multimission Aircraft Design Study, Payload, Ahmet Kahraman

Theses and Dissertations

It is proposed that a Multi-Mission Aircraft (MMA) be prepared to combine some or all the functions of the aging AWACS, JSTARS, RIVET JOINT, COMPASS CALL, and AECCC fleet. Three different thesis studies have been developed by three Air Force Institute of Technology GSE students to show the feasibility of replacing the current aging fleet with one or more MMA platforms. This is the thesis in which the payload issuer have been examined. Within this thesis, two different alternative architectures, which are One Tail Number and Different Tail Numbers including nine different configurations, have been considered. Estimated payload characteristics of …

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Cargo Aircraft Bombing System (Cabs), Gurler Ari Mar 2003

Cargo Aircraft Bombing System (Cabs), Gurler Ari

Theses and Dissertations

From the early days of aviation, bombs typically have been carried by either fighter or bomber aircraft in the inventory. On the other hand, more and more long-range, precision-guided missiles are being produced with ranges that vary from tens to hundreds of miles. With such missiles, targets can be destroyed without placing personnel and equipment into close proximity to the targets. The mass delivery of standoff weapons could be especially advantageous during the early phases of an air campaign. This study considers the use of cargo aircraft for carrying and launching bombs and missiles. It discusses many aspects of a …

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Analysis Of Cooperative Behavior For Autonomous Wide Area Search Munitions, Orhan Gozaydin Mar 2003

Analysis Of Cooperative Behavior For Autonomous Wide Area Search Munitions, Orhan Gozaydin

Theses and Dissertations

This research investigates the effectiveness of autonomous wide area search munitions using cooperative and non-cooperative behavior algorithms under various scenarios. The scenarios involve multiple autonomous munitions searching for an unknown number of targets with different priorities at unknown locations. For the cooperative cases, communications are allowed between the munitions to help locate, identify, and decide to pursue an attack on a target or to continue searching the rest of the battlefield. For non cooperative cases, munitions independently search, detect, identify and decide to attack an identified target or continue to search. Performance of the cooperative munitions depends on numerous parameters …

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Inquisitive Pattern Recognition, Amy L. Magnus Mar 2003

Inquisitive Pattern Recognition, Amy L. Magnus

Theses and Dissertations

The Department of Defense and the Department of the Air Force have funded automatic target recognition for several decades with varied success. The foundation of automatic target recognition is based upon pattern recognition. In this work, we present new pattern recognition concepts specifically in the area of classification and propose new techniques that will allow one to determine when a classifier is being arrogant. Clearly arrogance in classification is an undesirable attribute. A human is being arrogant when their expressed conviction in a decision overstates their actual experience in making similar decisions. Likewise given an input feature vector, we say …

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Development Of An Experimental Test Section For Forcing Unsteady Flow In A Linear Compressor Cascade Using Circular Rods, Patrick C. Wade Mar 2003

Development Of An Experimental Test Section For Forcing Unsteady Flow In A Linear Compressor Cascade Using Circular Rods, Patrick C. Wade

Theses and Dissertations

Upstream propagating waves impinging on a cascade of compressor blades were examined in an effort to better understand the influence of downstream components on high cycle fatigue in turbine engines. An array of cylinders was used to simulate the unsteady field generated by a rotor downstream of a set of stators. The unsteady flow upstream of a single cylinder and an array of cylinders, with and without an upstream cascade, was examined experimentally and computationally. Computational results indicate that the cylinders would only shed coherently when placed downstream of a set of blades. Coherent shedding is created when each of …

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Cold-Flow Testing Of A Subscale Model Exhaust System For A Space-Base Laser, Ian S. Bautista Mar 2003

Cold-Flow Testing Of A Subscale Model Exhaust System For A Space-Base Laser, Ian S. Bautista

Theses and Dissertations

The purpose of this research was to continue a study of gas-dynamic phenomena that occurred in stacked cylindrical rings of nozzles and an exhaust manifold as reported by Captain Scott Bergren in 2002. The rings and exhaust manifold were part of a 1/5-scale model of one quadrant of the conceptual Space Based Laser Integrated Flight Experiment (SBL IFX) gas dynamic laser. This model was mated to a blow- down/vacuum wind tunnel and consisted of a nozzle array, centerbody, supersonic diffuser, and a transition structure to mate the vacuum and test section. During Capt Bergren's research, supersonic flow was found to …

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Reduction Of Thermal Residual Strains In Adhesively Bonded Composite Repairs, Heather R. Crooks Mar 2003

Reduction Of Thermal Residual Strains In Adhesively Bonded Composite Repairs, Heather R. Crooks

Theses and Dissertations

Many military and commercial aircraft are being called upon to fly well beyond their original intended service lives. This has forced the United States Air Force (USAF) to increasingly rely on structural repairs to address fatigue induced damage and to extend aircraft useful life. The focus of this research is the use of a high-strength composite patch technique to repair a fatigue crack on an aluminum aircraft structure. This study investigates the thermal residual strains that occur as a direct result of the coefficient of thermal expansion (CTE) mismatch between the repair patch and the underlying cracked metallic structure to …

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The Effect Of A Hard Coating On The Damping And Fatigue Life Of Titanium, Frank T. Ivancic Mar 2003

The Effect Of A Hard Coating On The Damping And Fatigue Life Of Titanium, Frank T. Ivancic

Theses and Dissertations

This project compares the damping and fatigue life of bare titanium plates to those coated with magnesium aluminate spinel (mag spinel). Two different coating thicknesses were tested: .005" per side and .010" per side (total thicknesses of .010" and .020"). Dynamic ping tests were conducted on all specimens to determine their resonance frequencies. Laser vibrometry was used to determine the mode at each resonance frequency. Damping ratios were determined through the use of sine sweeps. A vibration mode was selected at which to fatigue the specimens, and the stress pattern was analyzed utilizing the Stress Pattern Analysis by Thermal Emissions …

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Experimental Demonstration Of An Algorithm To Detect The Presence Of A Parasitic Satellite, Vincent J. Dabrowski Mar 2003

Experimental Demonstration Of An Algorithm To Detect The Presence Of A Parasitic Satellite, Vincent J. Dabrowski

Theses and Dissertations

Published reports of microsatellite weapons testing have led to a concern that some of these "parasitic" satellites could be deployed against US satellites to rendezvous dock and then disrupt, degrade disable or destroy the system. An effective detection method is essential. Various sensing solutions were investigated including visual, impact, and dynamic techniques. Dynamic detection, the most effective solution, was further explored. A detection algorithm was constructed and validated on the Air Force Institute of Technology's ground-based satellite simulator, SIMSAT. Results indicate that microsat microsatellites rigidly connected to a satellite can be detected with a series of small identical maneuvers utilizing …

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A Comparison Of Nonlinear Algorithms To Prevent Pilot-Induced Oscillations Caused By Actuator Rate Limiting, James G. Hanley Mar 2003

A Comparison Of Nonlinear Algorithms To Prevent Pilot-Induced Oscillations Caused By Actuator Rate Limiting, James G. Hanley

Theses and Dissertations

The objective of this study was to compare the ability of the Feedback-with-Bypass (FWB) and the Derivative-Switching (DS) flight control system filters to prevent PIO during actuator rate limiting, and the filters' effects on aircraft handling qualities. This comparison was conducted in three steps: computer simulation, ground simulation in the Large Amplitude Multimode Aerospace Research Simulator (LAMARS), and flight tests conducted in the Variable Stability In-flight Simulator Test Aircraft (VISTA). During computer simulation, the FWB filter better reduced the phase lag and prevented sustained or divergent oscillations during the closed-loop analysis. During both ground simulation and flight tests, the FWB …

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Sensor-Craft Analytical Certification, Ronald W. Roberts Jr. Mar 2003

Sensor-Craft Analytical Certification, Ronald W. Roberts Jr.

Theses and Dissertations

This study developed a multi-disciplinary conceptual design of a joined-wing sensor-craft. Initial analysis was conducted using an aluminum model. Linear fully stressed design and flexible aerodynamic trim were used to converge to a minimum weight design that was aerodynamically stable. This optimized design was buckling safe. A similar optimization process using non-linear fully stressed design and flexible aerodynamic trim was conducted. The non- linear structurally deformation was over ten times greater than the linear structural deformation. Again, the model was structurally and aerodynamically optimized. The linear optimization was repeated using a composite structural model incorporating Conformal Load-bearing Antenna Structures. This …

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Nonlinear, Transonic Flutter Prediction For F-16 Stores Configuration Clearance, Raymond G. Toth Mar 2003

Nonlinear, Transonic Flutter Prediction For F-16 Stores Configuration Clearance, Raymond G. Toth

Theses and Dissertations

Wing flutter, or more accurately limit cycle oscillation (LCO), has been an issue for the F-16 since its operational deployment. Different store configurations and the permutations of those configurations after weapons are released will cause LCO to either disappear or appear. Unfortunately, the current method used by engineers for predicting LCO onset is based on linear, subsonic aerodynamic theory with no corrections for transonic effects. Predictions using this method are often good in frequency, but can be far off in predicting onset speed, forcing flutter engineers to rely more on experience and interpolation from similar configurations to design flight test …

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Structurally Integrated Antennas On A Joined-Wing Aircraft, Ben P. Smallwood Mar 2003

Structurally Integrated Antennas On A Joined-Wing Aircraft, Ben P. Smallwood

Theses and Dissertations

This research is a foundational study of conformal, load-bearing antenna arrays embedded into the wing structure of a joined-wing aircraft. It is a multidisciplinary effort that touches on the aerodynamic structural and electromagnetic design considerations that stem from this unique type of sensor integration. The antenna performance Finite Element Model (FEM) and control surface effectiveness are investigated. The theory describing an ensemble of dipole antenna elements that conform to the shape of a section of the joined wing is developed. The far held flee space radiation pattern of the sensor is then analyzed for a wing that is deflected due …

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Hybrid Control Strategies For Rapid, Large Angle Satellite Slew Maneuvers, David B. French Mar 2003

Hybrid Control Strategies For Rapid, Large Angle Satellite Slew Maneuvers, David B. French

Theses and Dissertations

This research investigated hybrid control strategies for rapid satellite pointing. First, a detailed computer simulation model of AFIT's SIMSAT satellite simulator was constructed. Control strategies were developed to enable the system to perform large-angle, 3-axis slewing maneuvers using a combination of both thrusters and reaction wheels. To handle the non-linear model, a State Dependent Riccati Equation controller was programmed and successfully controlled the computer-modeled satellite for any given slewing maneuver. A simpler PD controller was then programmed and demonstrated on the computer simulation of SIMSAT, using a combination of thruster and reaction wheel control inputs for large-angle single axis maneuvers …

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The Air Warrior's Value Of National Security Space, John D. Loftis Mar 2003

The Air Warrior's Value Of National Security Space, John D. Loftis

Theses and Dissertations

The 2001 Report of the Commission to Assess United States National Security Space Management and Organization recommended that U.S. efforts in national security space be elevated to the highest national security priority. With more focused high-level attention on national security space decisions a measure that captures and quantities the value of space capabilities to combat operations professionals is desired. This thesis models what the air warriors desire from space assets in combat. A Value-Focused Thinking (VFT) approach was used to elicit values from air combat experts with operational experience. An initial Gold Standard value model was constructed and validated by …

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Development, Fabrication And Ground Test Of An Inflatable Structure Space-Flight Experiment, Thomas L. Philley Jr. Mar 2003

Development, Fabrication And Ground Test Of An Inflatable Structure Space-Flight Experiment, Thomas L. Philley Jr.

Theses and Dissertations

Inflatable, rigidizable structures provide a solution to reduce the costs associated with design, fabrication and launch of a space system while simultaneously increasing the deployment reliability and mission success of the system%. This research focused on the follow on design, fabrication, and ground test of the Rigidizable Inflatable Get-Away-Special Experiment (RIGEX). RIGEX is a self-contained experiment that will test the deployment and structural characteristics of three inflatable rigidizable tubes. Once inflated and rigidized, each tube will be excited using piezoelectric transducers in order to collect vibration data for structural characterization. The goal of this research was to collect ground testing …

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Auto Carrier Transporter Loading And Unloading Improvement, Brian M. Miller Mar 2003

Auto Carrier Transporter Loading And Unloading Improvement, Brian M. Miller

Theses and Dissertations

Thousands of vehicles (cars, trucks and vans) are transported every day from one location to another. These vehicles are moved around the country on Auto Carrier Transports (ACTs). Delivering these vehicles involves large quantities of time, money and energy. Any reduction in time and energy will result in a significant savings of money. The intent of this research is to develop an algorithm to solve the Auto Carrier Transport Pickup and Delivery Problem. In doing so, the focus is to limit the total times vehicles are placed on and taken off the carrier, otherwise known as the number of loads, …

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Orbit Determination For A Microsatellite Rendezvous With A Non-Cooperative Target, Brian L. Foster Mar 2003

Orbit Determination For A Microsatellite Rendezvous With A Non-Cooperative Target, Brian L. Foster

Theses and Dissertations

This study investigated the minimum requirements to establish a satellite tracking system architecture for a hostile "parasitic microsatellite" to rendezvous with a larger, non-cooperative target satellite. Four types of tracking systems and their capabilities were reviewed with emphasis on "low-technology" level and/or mobile systems which could be used by technologically unsophisticated state or non-state adversaries. With the tracking system architecture selected, simulated tracking data was processed with a non- linear least squares orbit determination filter to determine and/or update the target satellite's state vector.

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A Study Of Control Laws For Microsatellite Rendezvous With A Non-Cooperative Target, Troy A. Tschirhart Mar 2003

A Study Of Control Laws For Microsatellite Rendezvous With A Non-Cooperative Target, Troy A. Tschirhart

Theses and Dissertations

This study investigated the feasibility of using a microsatellite to accomplish an orbital rendezvous with a noncooperative target, with a focus on the control laws necessary for achieving such a rendezvous. The relative motions of the microsatellite and the target satellite are described using Hill's equations. The results of an investigation of two different controller methodologies show that an impulsive thrust controller based on the Clohessey-Wiltshire solution used little fuel, but was not very robust. A continuous thrust controller using a Linear Quadratic Regulator was found to be more robust, but used much more fuel. As a final solution, a …

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A Service Life Analysis Of Coast Guard C-130 Aircraft, Jonathan B. Duff Mar 2003

A Service Life Analysis Of Coast Guard C-130 Aircraft, Jonathan B. Duff

Theses and Dissertations

The U. S. Coast Guard, much like the rest of the Armed Services, is facing a dramatic transformation of its forces to meet current and future service requirements. The Coast Guard has responded to this transformation by initiating the Deepwater System, a complete review of the offshore mission requirements and the modernization of its infrastructure. In particular, Deepwater will review and modernize the Coast Guard's aviation assets, improving aircraft systems, airborne sensors, and communications and information management systems. However, these capability advancements will take time and money to implement, and will require careful management of the current resources to ensure …

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A Simulation-Based Analysis Of The Impact Of In-Sourcing A Major Process Element On The Coast Guard Hh-601 Depot Maintenance Process, Steven E. Vigus Mar 2003

A Simulation-Based Analysis Of The Impact Of In-Sourcing A Major Process Element On The Coast Guard Hh-601 Depot Maintenance Process, Steven E. Vigus

Theses and Dissertations

Leaders at the United States Coast Guard's Aircraft Repair and Service Center (ARSC) in Elizabeth City, North Carolina recently formalized their planning and analysis functions by adding a dedicated branch to their command structure. The Planning and Analysis Branch intends to apply computer modeling and simulation to study the impact of process changes to the various Programmed Depot Maintenance (PDM) lines. This research considers the applicability of this type of modeling and simulation, using ARENA to study the current HH-6OJ PDM process. The contribution of this research is a methodology specific to ARSC needs, an analysis of methodology based on …

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