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Articles 9511 - 9540 of 11503

Full-Text Articles in Engineering

Using Neural Networks For Estimating Cruise Missile Reliability, Donald L. Hoffman Mar 2003

Using Neural Networks For Estimating Cruise Missile Reliability, Donald L. Hoffman

Theses and Dissertations

ACC believes its current methodology for predicting the reliability of its Air Launched Cruise Missile (ALCM) and Advanced Cruise Missile (ACM) stockpiles could be improved. They require a predictive model that delivers the best possible 24-month projection of cruise missile reliability using existing data sources, collection methods and software. It should be easily maintainable and developed to allow a layperson to enter updated data and receive an accurate reliability prediction. The focus of this thesis is to improve upon free flight reliability, although the techniques could also be applied to the captive carry portion of the missile reliability equation. The …

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Physical Fitness And The Expeditionary Air Force, Elizabeth T. Lewis Mar 2003

Physical Fitness And The Expeditionary Air Force, Elizabeth T. Lewis

Theses and Dissertations

The Air Force is constantly evolving. With the many changes and the Expeditionary Air Force structure put in place, it is more important now than ever that the Air Force has a physical fitness program to keep its members healthy and productive. By doing this, it can ensure success in completing the Air Force mission while keeping the organization at the highest level of readiness possible. This thesis looks at what the Air Force values in having a fitness program. These values are taken from Air Force doctrine and related instructions. Using these values, fitness programs can be evaluated to …

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Use Of Multivariate Techniques To Validate And Improved The Current Usaf Pilot Candidate Selection Model, Ross A. Keener Mar 2003

Use Of Multivariate Techniques To Validate And Improved The Current Usaf Pilot Candidate Selection Model, Ross A. Keener

Theses and Dissertations

The Pilot Candidate Selection Method (PCSM) seeks to ensure the highest possible probability of success at UPT. PCSM applies regression weights to a candidate's Air Force Officer Qualification Test (AFOQT) Pilot composite score, self-reported flying hours, and five Basic Attributes Test (BAT) score composites. PCSM scores range between 0 and 99 and is interpreted as a candidate's probability of passing UPT. The goal of this study is to apply multivariate data analysis techniques to validate PCSM and determine appropriate changes to the model's weights. Performance of the updated weights is compared to the current PCSM model via Receiver Operating Curves …

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Analysis Of Organizational Architectures For The Air Force Tuition Assistance Program, Krista Z. Lapietra Mar 2003

Analysis Of Organizational Architectures For The Air Force Tuition Assistance Program, Krista Z. Lapietra

Theses and Dissertations

The consideration of restructuring through a change in organizational architecture is often a fiercely debated issue within an organization. The argument for restructuring to improve quality, customer service, and financial management is pitted against perceived lack of job security and historically poor results from previous restructuring initiatives. To balance all sides when considering a change in organizational architecture, the organization should use a method of evaluating potential architectures that assists in determining the best new architecture and generates support from those involved. The objective of this research is to provide the Air Force Education Division with a defendable methodology for …

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Air Force Reserve Force Structure Policy Evaluation Model, Scott A. Percival Mar 2003

Air Force Reserve Force Structure Policy Evaluation Model, Scott A. Percival

Theses and Dissertations

The United States Air Force Reserve is a constantly changing force. In response to these changes, the Active Guard Reserve (AGR), a small organization within the Reserve, is seeking to create a career track for Unit and Headquarters' Officers. It is necessary for the AGR policy division to be able to evaluate the availability of career paths to accomplish this goal. The Air Force Reserve Force Structure Evaluation Model provides the AGR management with a tool to aid them in evaluating policy impact. This model allows the AGR management to identify the impact policy changes may have on the resulting …

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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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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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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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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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The Air Force Operational Risk Management Program And Aviation Safety, Matthew G. Cho Mar 2003

The Air Force Operational Risk Management Program And Aviation Safety, Matthew G. Cho

Theses and Dissertations

Aviation mishaps are extremely costly in terms of dollar value, public opinion, and human life, The Air Force drastically reduced Class A mishap rates in its formative years. The rate plummeted from 44.22 mishaps per 100,000 flight hours in 1947 to 2.33 mishaps in 1983 and has held steady around 1.5 mishaps since. The Air Force implemented the Operational Risk Management (ORM) program in 1996 in an effort to protect their most valuable resources: aircraft and aviators. An AFIT thesis conducted in 1999 by Capt Park Ashley studied the Army similar Risk Management (RM) program. Ashley concluded that since his …

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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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Groundwater Flow Through A Constructed Treatment Wetland, Jack A. Blalock Mar 2003

Groundwater Flow Through A Constructed Treatment Wetland, Jack A. Blalock

Theses and Dissertations

This study is an analysis of the flow of water through a constructed treatment wetland at Wright-Patterson AFB, OH. The purpose of the treatment wetland is to biodegrade perchioroethylene, which is present in the groundwater as a contaminant. Contaminated water enters the bottom of the wetland and flows upward, exiting the wetland from a weir at one end. The wetland is designed for water to move vertically through the soil layers composing the wetland. The main purpose of this study is to characterize the water flow through the different layers of soil in the wetland. In this study, hydraulic parameters …

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Modeling Catalytic Destruction Of Subsurface Contaminants In Recirculating Wells, Kerry J. Cadena Mar 2003

Modeling Catalytic Destruction Of Subsurface Contaminants In Recirculating Wells, Kerry J. Cadena

Theses and Dissertations

Groundwater and soil contamination is a significant problem throughout the nation, with approximately 300,000 to 400,000 sites affected (National Research Council, 1994). Examples of groundwater contaminants of special interest to DoD and AF installations include fuel hydrocarbons, chlorinated hydrocarbons, and nitroaromatic compounds. Traditional remediation technologies, which include pump-and-treat, permeable reactive barriers, and natural attenuation, have numerous drawbacks associated with them. These drawbacks have prompted researchers to look for innovative contamination clean-up methods. The technology investigated in this thesis, reticulating horizontal flow treatment wells (HFTWs) with in-well palladium (Pd) catalyst reactors, offers the potential for destruction of groundwater contaminants commonly found …

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A Proposed Military Construction Facility Investment Model, Andre R. Dempsey Mar 2003

A Proposed Military Construction Facility Investment Model, Andre R. Dempsey

Theses and Dissertations

The fiscal year (FY) 1999 and FY2000 National Defense Authorization Acts (NDAA) amended Title 10 USC, Section 17, and directed the secretary of defense to report annually on the capability of installations and facilities to provide support to forces in the conduct of their missions. This has come to be known as the Installations' Readiness Report (IRR). The Air Force's IRR links facility sustainment, restoration, and modernization (SRM) requirements, with the impact on the installation's ability to support the mission associated with the particular facility class. The Air Force's centralized military construction (MILCON) program model used to program major facility …

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The Effects Of Ionizing Radiation On Microelectromechanical Systems (Mems) Actuators: Electrostatic, Electrothermal, And Residual Stress, Jared R. Caffey Mar 2003

The Effects Of Ionizing Radiation On Microelectromechanical Systems (Mems) Actuators: Electrostatic, Electrothermal, And Residual Stress, Jared R. Caffey

Theses and Dissertations

The effects of ionizing radiation on the operation of polysilicon mmicroelectromechanical system (MEMS) electrostatic actuators, electrothermal actuators, and residual stress cantilevers were examined. Pre-irradiation, in-situ, and post-irradiation measurements were taken for the electrosatic and electrothermal actuators. The residual stress cantilevers were characterized before and after irradiation. All devices were irradiated to a total ionizing does of 1 megarad(Si) using both the Air Force Research Laboratory's low energy X-ray source and Co-60 gamma source.

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Analysis Of Broadband Higp-Impedance Ground Plane Antenna Designs, James W. Stewart Mar 2003

Analysis Of Broadband Higp-Impedance Ground Plane Antenna Designs, James W. Stewart

Theses and Dissertations

This research ties together computational and experimental analysis of two types of high-impedance ground plane (HIGP) antennas. One type of antenna consists of a proposed two-layer design. The structure consists of a bowtie antenna mounted over the surface of a HIGR The proposed structure was intended to achieve a resonant frequency of 3 GHz and a bandwidth of 48%; however, a design error results in a significant mismatch in operating bands between the antenna and HIGR Experiment results indicate the structure performs poorly across the entire measured band of 2-5 GHz. A new two-layer design is developed and presented. The …

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Quantum Mechanical Calculations Of Monoxides Of Silicon Carbide Molecules, John W. Roberts Jr. Mar 2003

Quantum Mechanical Calculations Of Monoxides Of Silicon Carbide Molecules, John W. Roberts Jr.

Theses and Dissertations

Modern semiconductor devices are principally made using the element silicon. In recent years, silicon carbide (SiC), with its wide band-gap, high thermal conductivity, and radiation resistance, has shown prospects as a semiconductor material for use in high temperature and radiation environments such as jet engines and satellites. A limiting factor in the performance of many SiC semiconductor components is the presence of lattice defects formed at oxide dielectric junctions during processing. Recent theoretical work has used small quantum mechanical systems embedded in larger molecular mechanics structures to attempt to better understand SiC surfaces and bulk materials and their oxidation. This …

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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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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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An Analysis Of Multiple Layered Networks, Kevin T. Kennedy Mar 2003

An Analysis Of Multiple Layered Networks, Kevin T. Kennedy

Theses and Dissertations

Current infrastructure network models of single functionality do not typically account for the interdependent nature of infrastructure networks. Infrastructure networks are generally modeled individually, as an isolated network or with minimal recognition of interactions. This research develops a methodology to model the individual infrastructure network types while explicitly modeling their interconnected effects. The result is a formulation built with two sets of variables (the original set to model infrastructure characteristics and an additional set representing cuts of interdependent elements). This formulation is decomposed by variable type using Benders Partitioning and solved to optimality using a Benders Partitioning algorithm. Current infrastructure …

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An Analysis Of The Efficacy Of The Logistics Composite Model In Estimating Maintenance Manpower Productive Capacity, Kirk B. Pettingill Mar 2003

An Analysis Of The Efficacy Of The Logistics Composite Model In Estimating Maintenance Manpower Productive Capacity, Kirk B. Pettingill

Theses and Dissertations

The Logistics Composite Model (LCOM) is the tool of choice for many MAJCOM's (ACC, USAFE, AFMC) in determining maintenance manpower requirements. The LCOM is a simulation program capable of modeling the manpower, equipment, supplies, and facilities required to conduct aircraft maintenance activities, Manpower studies conducted with the LCOM result in manpower estimates that end up in Unit Manning Documents (UMD) as "LCOM earned," authorized positions. This research effort focuses on whether the LCOM can also be used to determine maintenance manpower's current capacity. Three different flying units at Cannon AFB, NM were modeled to determine if the LCOM, when programmed …

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Theoretical Comparison Of The Excited Electronic States Of The Linear Uranyl (Uo22+) And Tetrahedral Uranate (Uo42-) Ions Using Relativistic Computational Methods, Eric V. Beck Mar 2003

Theoretical Comparison Of The Excited Electronic States Of The Linear Uranyl (Uo22+) And Tetrahedral Uranate (Uo42-) Ions Using Relativistic Computational Methods, Eric V. Beck

Theses and Dissertations

This thesis examines the ground and excited electronic states of the uranyl (UO2+) and uranate (UO42-) ions using Hartree-Fock self-consistent field (HF SCF), multi-configuration self-consistent field (MCSCF) and multi-reference single and double excitation configuration interaction (MR- CISD) methods. The MR-CISD SD calculation included spin-orbit operators. Molecular geometries were obtained from self-consistent field (SCF ) second-order perturbation theory (MP2), and density functional theory (DFT) geometry optimizations using the NWChem 4.01 massively parallel ab initio software package. COLUMBUS version 5.8 was used to perform in-depth analysis on the HF SCF MCSCF and MR-CISD potential energy surfaces. Excited …

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Stress Analysis Of Silicon Carbide Microeletromechanical Systems Using Raman Spectroscopy, Stanley J. Ness Mar 2003

Stress Analysis Of Silicon Carbide Microeletromechanical Systems Using Raman Spectroscopy, Stanley J. Ness

Theses and Dissertations

During the fabrication of Micro-Electro-Mechanical Systems (MEMS), residual stress is often induced in the thin films that are deposited to create these systems. These stresses can cause the device to fail due to buckling, curling, or fracture. Government and industry are looking for ways to characterize the stress during the deposition of thin films in order to reduce or eliminate device failure. Micro-Raman spectroscopy has been successfully used to analyze poly-silicon MEMS devices made with the Multi-User MEMS Process (MUMPS trade name). Micro-Raman spectroscopy was selected because it is nondestructive, fast and has the potential for in situ stress monitoring. …

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Total Dose Effects Of Ionizing And Non-Ionizing Radiation On Piezoresistive Pressure Transducer Chips, Samuel J. Willmon Mar 2003

Total Dose Effects Of Ionizing And Non-Ionizing Radiation On Piezoresistive Pressure Transducer Chips, Samuel J. Willmon

Theses and Dissertations

The effects of ionizing and non ionizing radiation on the resistivity of silicon based, piezoresistive bulk micro-machined chips from pressure transducers were examined. Standard current-voltage (I-V) measurements were taken in-situ and post-irradiation during isothermal annealing at room temperature. One group of chips was irradiated to a maximum total gamma dose of lMrad(Si) in the 11,000 Ci (60) Co gamma cell at Ohio State University. The second group of chips was irradiated at the Ohio State University Research Reactor facility to a maximum total neutron dose of 4 Mrad(Si) using beam port Hi. The resistivity was shown to decrease during gamma …

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Evaluating The Performance Of Multiple Classifier Systems: A Matrix Algebra Representation Of Boolean Fusion Rules, Justin M. Hill Mar 2003

Evaluating The Performance Of Multiple Classifier Systems: A Matrix Algebra Representation Of Boolean Fusion Rules, Justin M. Hill

Theses and Dissertations

Given a finite collection of classifiers one might wish to combine, or fuse, the classifiers in hopes that the multiple classifier system (MCS) will perform better than the individuals. One method of fusing classifiers is to combine their final decision using Boolean rules (e.g., a logical OR, AND, or a majority vote of the classifiers in the system). An established method for evaluating a classifier is measuring some aspect of its Receiver Operating Characteristic (ROC) curve, which graphs the trade-off between the conditional probabilities of detection and false alarm. This work presents a unique method of estimating the performance of …

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Combining And Analyzing The Tanker And Aircrew Scheduling Heuristics, Cem Boke Mar 2003

Combining And Analyzing The Tanker And Aircrew Scheduling Heuristics, Cem Boke

Theses and Dissertations

Air refueling is an integral part of U.S. air power across a wide range of military operations. It is an essential capability in the conduct of air operations worldwide and is especially important when overseas basing is limited or not available. The planning, tasking, and scheduling of aerial refueling require solution of two major problems: assigning and scheduling of tankers to refueling points and efficiently assigning crews to each tanker. To address the scheduling of tankers, Wiley (2001) developed an efficient tabu search approach. Combs (2002) developed another tabu search approach to assign crews to tankers. This research combines the …

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