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Full-Text Articles in Engineering

Combined Stereo Vision And Inertial Navigation For Automated Aerial Refueling, Daniel T. Johnson Mar 2017

Combined Stereo Vision And Inertial Navigation For Automated Aerial Refueling, Daniel T. Johnson

Theses and Dissertations

This paper describes the design of an EKF to obtain the precise relative position of two aircraft in a refueling maneuver while operating in GPS denied environments. The EKF uses the INS already present in both aircraft as well as the stereo camera system organic to new tanker systems. The aircraft trajectories are generated according to authentic refueling profiles with flight dynamics software and executed in a 3D virtual environment to enable deterministic simulation of the stereo camera system and to demonstrate the effectiveness of the combined system in a refueling scenario. Results show the system can achieve sufficient accuracy …

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A Framework For Understanding, Prioritizing, And Applying Systems Security Engineering Processes, Activities, And Tasks, Stephen Khou Mar 2017

A Framework For Understanding, Prioritizing, And Applying Systems Security Engineering Processes, Activities, And Tasks, Stephen Khou

Theses and Dissertations

Current systems security practices lack an effective approach to prioritize and tailor systems security efforts to develop and field secure systems in challenging operational environments, which results in business and mission stakeholders becoming more susceptible to an array of disruptive events. This work informs Systems Engineers on recent developments in the field of system security engineering and provides a framework for more fully understanding the application of Systems Security Engineering (SSE) processes, activities, and tasks as described in the recently released National Institute of Standards and Technology (NIST) Special Publication 800-160. This SSE framework uniquely offers a repeatable and tailorable …

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An Empirical Analysis Of Air Force Military Construction Project Delivery Method Performance In The United States, Erich C. Kramer Mar 2017

An Empirical Analysis Of Air Force Military Construction Project Delivery Method Performance In The United States, Erich C. Kramer

Theses and Dissertations

The objective of this study is to investigate the performance of the design-bid-build and design-build project delivery methods in Air Force military construction (MILCON). Project delivery performance is measured through quantitative cost, schedule, and change order metrics for 264 design-bid-build and 316 design-build MILCON projects from 2003-2014. The average response measures were statistically compared within each delivery method using three independent variables: time, facility type, and major command (MAJCOM). The historical analysis revealed that the current working estimate programmed amount ratios improved over time for design-build projects, and an overall consistency in schedule growth and project duration performance occurred across …

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Development Of The Architecture Cost Effectiveness Framework And Application To Open Systems Architectures, Donald A. Barrett Mar 2017

Development Of The Architecture Cost Effectiveness Framework And Application To Open Systems Architectures, Donald A. Barrett

Theses and Dissertations

The Modular Open System Approach (MOSA) is an initiative to, among other things, reduce cost and schedule for acquisitions programs. While programs have experienced savings using MOSA, the majority of programs have not, in part due to a lack of a logical method for evaluating architecture alternatives. This research develops the Architecture Cost Effectiveness Framework (ACEF), which combines multi-attribute utility analysis with cost effectiveness analysis throughout the program lifecycle. Step 1 is the establishment of a business strategy that includes an Attribute Hierarchy of selected operational requirements. The business strategy also defines Lifecycle Utility Reference Profiles (LURPs) that document changing …

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Toxicological Differences Between Perfluoroalkyl Substances (Pfas) Isomers Using Developmental Biomarkers, Gabriel A. Cantu Mar 2017

Toxicological Differences Between Perfluoroalkyl Substances (Pfas) Isomers Using Developmental Biomarkers, Gabriel A. Cantu

Theses and Dissertations

Perfluoroalkyl substances (PFAS) are metabolically stable synthetic chemicals that have been manufactured for commercial and industrial purposes since the 1950s. PFAS possess surfactant properties that make them ideal to fight hydrocarbon fires and are therefore present in aqueous film forming foams (AFFF). Furthermore, AFFF may contain blends of both linear and branched PFAS isomers. Research suggests that branched PFAS isomers have greater relative placental transfer efficiencies than their linear counterpart, but few studies have evaluated their toxicity. Therefore, the sustained use of AFFF in the U.S. Air Force presents a risk of branched PFAS exposures in pregnant females. This study …

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Enhancing The Thermal Performance Of Temporary Fabric Shelters For The Advanced Energy Efficient Shelter System, Justin E. Eshleman Mar 2017

Enhancing The Thermal Performance Of Temporary Fabric Shelters For The Advanced Energy Efficient Shelter System, Justin E. Eshleman

Theses and Dissertations

Investment in the commercial space industry has grown significantly over the past decade. This investment has led to a tremendous leap in capability for small satellite systems and a greater demand for small launch vehicles. At the same time, space system affordability is a point of emphasis within the Department of Defense (DoD) which raises the question: Can the DoD lower space access costs through the exploitation of the growing small satellite and small launch marketplace? We perform a financial analysis of newly developed small launch vehicles delivering a small satellite constellation to low earth orbit (LEO) to perform wideband …

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Learning Curves: An Alternative Analysis, Sharif F. Harris Mar 2017

Learning Curves: An Alternative Analysis, Sharif F. Harris

Theses and Dissertations

Learning curves are used to describe and estimate the cost performance of a serial production process. There are numerous different models and methods, however, it is not definitively known which is preferred. The research objective is to performance compare the more common learning curve models. The research goal is improved understanding of the systemic cost drivers of a production process, their relationship to cost, and present modeling methods. The research method is qualitative analysis combined with statistical regression modeling. The research identified that preference for one function or another depended upon the shape of the data and how well a …

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Alternate Stimuli For The Elicitation Of Event-Related Potentials, Bryan V. Jackson Mar 2017

Alternate Stimuli For The Elicitation Of Event-Related Potentials, Bryan V. Jackson

Theses and Dissertations

Brain-Computer Interfaces (BCIs) are systems that leverage user-brain activity to identify and perform specific functions. In applications requiring overt visual attention, focusing on visual stimuli with known temporal variation can elicit measurable changes in brain activity. However, elements of BCI applications can be intrusive. This research was designed to determine if Event-Related Potentials (ERPs), to include Steady-State Visually-Evoked Potentials (SSVEPs), could be elicited and interpreted from less obtrusive stimuli. Specifically, this research explores the use of variable frequency and long-wavelength (infrared) stimuli for SSVEP interpretation to explore the application of less obtrusive stimuli for application in BCIs. It was determined …

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A Framework For Analyzing And Discussing Level Of Human Control Abstraction, Clifford D. Johnson Mar 2017

A Framework For Analyzing And Discussing Level Of Human Control Abstraction, Clifford D. Johnson

Theses and Dissertations

It is often useful to understand the impact of an artificial teammate upon human workload in human-machine teams. Levels of Autonomy (LoA) differentiate systems based on control authority. Unfortunately, human workload is not necessarily correlated with LoA. An alternate classification framework, designated the Level of Human Control Abstraction (LHCA), is proposed. LHCA differentiates system states based on the control and monitoring tasks performed and the level of decisions made by humans. The framework defines five levels, designed to differentiate between system states based upon anticipated levels of human attention. This presentation will summarize the framework and demonstrate its application.

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An Investigation Into The Indicators Of A Successful Total Force Association, Greg E. Hoyt Mar 2017

An Investigation Into The Indicators Of A Successful Total Force Association, Greg E. Hoyt

Theses and Dissertations

The Air Force, since adopting and subsequently developing the Total Force concept in the early 1970s, has not thoroughly outlined clear objectives by which the progress toward and realization of this strategic vision should be defined and measured. Without clear definition, direction, and method of evaluation, the ability to credibly claim any subsequent successes or failures in the pursuit of this vision become vulnerable to challenge. Indeed, the mere claim that a single, clear vision exists may be challenged. The Total Force concepts degree of success has, on multiple occasions through its history, been critiqued with the most recent instance …

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Real-Time Heuristic Algorithms For The Static Weapon-Target Assignment Problem, Alexander G. Kline Mar 2017

Real-Time Heuristic Algorithms For The Static Weapon-Target Assignment Problem, Alexander G. Kline

Theses and Dissertations

The problem of targeting and engaging individual missiles (targets) with an arsenal of interceptors (weapons) is known as the weapon target assignment problem. As many solution techniques are based upon a transformation of the objective function, their final solutions rarely produce optimal solutions. We propose a nonlinear branch and bound algorithm to provide the first optimization approach to the untransformed problem found in the literature. Further, we propose a new heuristic based upon the branch and bound algorithm which dominates other heuristics explored in optimality gap. We also propose a heuristic based upon the optimal solution to the quiz problem …

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Predicting Solar Performance In A Contingency Environment To Meet Net-Zero Facility Power, Anthony D. Williams Mar 2017

Predicting Solar Performance In A Contingency Environment To Meet Net-Zero Facility Power, Anthony D. Williams

Theses and Dissertations

The U.S. government is involved in contingency operations all over the world and these operations require operational support and sustainment in these locations; this includes the reliable delivery of power to base infrastructure. The traditional means of delivering this support requirement in austere environments has been the use of diesel-power generation that has an extensive logistical and economic tail. The research sought out contingency solar applications that may be implemented and operated to offset the facility demand loads in the location to achieve net-zero power. This research explores the technical feasibility of a deployable photovoltaic microgrid to deliver power to …

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The Impact Of Atmospheric Fluctuations On Optimal Boost Glide Hypersonic Vehicle Dynamics, Melissa A. Dunkel Mar 2017

The Impact Of Atmospheric Fluctuations On Optimal Boost Glide Hypersonic Vehicle Dynamics, Melissa A. Dunkel

Theses and Dissertations

A project under the management of Air Force Research Laboratory has begun development of a six degree of freedom model for use in hypersonic vehicle development and application. One area of interest is the perturbation of vehicle behavior based on atmospheric fluctuations – how the performance of the vehicle changes with respect to “hot”, “cold” and standard day conditions. The method developed to fill this need uses real-world data from the Global Forecast System to create a “hot” and “cold” day dataset to compare with the standard day model. The key parameter is atmospheric density, a value calculated over a …

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A System Dynamics Model Investigating The Efficacy Of Non-Kinetic Policy Strategies On The Diffusion Of Democratic Ideologies In China, Maria S. Phillips Mar 2017

A System Dynamics Model Investigating The Efficacy Of Non-Kinetic Policy Strategies On The Diffusion Of Democratic Ideologies In China, Maria S. Phillips

Theses and Dissertations

Shaping the next century of global politics and power, United States-China relations comprise one of the most significant bilateral relationships in the world. A new era of unrestricted warfare is one example of how aggression from China could be very costly for the United States. The growth of democratic ideals within China decreases the risk of detrimental impacts according to democratic peace theory. This thesis explores a multifaceted system of relationships that regulate the diffusion of democratic ideology within China, as defined by a proxy-measure characterized as human rights by Freedom House. Relative deprivation theory coupled with an adapted Bass …

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An Approximate Dynamic Programming Approach For Comparing Firing Solutions In A Networked Air Defense Environment, Daniel S. Summers Mar 2017

An Approximate Dynamic Programming Approach For Comparing Firing Solutions In A Networked Air Defense Environment, Daniel S. Summers

Theses and Dissertations

The United States Army currently employs a shoot-shoot-look firing policy for air defense. As the Army moves to a networked defense-in-depth strategy, this policy will not provide optimal results for managing interceptor inventories in a conflict to minimize the damage to defended assets. The objective for air and missile defense is to identify the firing policy for interceptor allocation that minimizes expected total cost of damage to defended assets. This dynamic weapon target assignment problem is formulated first as a Markov decision process (MDP) and then approximate dynamic programming (ADP) is used to solve problem instances based on a representative …

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An Analysis Of Radio-Frequency Geolocation Techniques For Satellite Systems Design, Daniel R. Barnes Mar 2017

An Analysis Of Radio-Frequency Geolocation Techniques For Satellite Systems Design, Daniel R. Barnes

Theses and Dissertations

This research 1) evaluates the effectiveness of CubeSat radio-frequency geolocation and 2) analyzes the sensitivity of different RF algorithms to system parameters. A MATLAB simulation is developed to assess geolocation accuracy for variable system designs and techniques (AOA, TDOA, T/FDOA). An unconstrained maximum likelihood estimator (MLE) and three different digital elevation models (DEM) are utilized as the surface of the Earth constraint to improve geolocation accuracy. The results presented show the effectiveness of the MLE and DEM techniques, the sensitivity of AOA, TDOA, and T/FDOA algorithms, and the system level performance of a CubeSat geolocation cluster in a 500km circular …

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Analysis Of Additively Manufactured Lattice Structures Using Finite Element Methods, Christopher A. Box Mar 2017

Analysis Of Additively Manufactured Lattice Structures Using Finite Element Methods, Christopher A. Box

Theses and Dissertations

Additive Manufacturing (AM) processes are well known for their ability to fabricate parts with complex geometries. Lattice structures leverage this ability to create parts with high strength-to-weight ratio and other desirable structural qualities. This research presents a parameterized modeling tool using common Finite Element Analysis (FEA) and scripting software with which aggregated lattice structures can be analyzed, given different geometric properties and loading conditions. A full factorial Design of Experiments is run to explore the effects of various parameters on the strength of lattice structures. Experimental compressive strength results from three FDM-produced PLA lattices are discussed and compared to predictions …

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Fatigue Behavior Of An Advanced Melt-Infiltrated Sic/Sic Composite At 1200°C In Air And In Steam, Nicholas J. Boucher Mar 2017

Fatigue Behavior Of An Advanced Melt-Infiltrated Sic/Sic Composite At 1200°C In Air And In Steam, Nicholas J. Boucher

Theses and Dissertations

The tension-tension fatigue behavior of an advanced melt-infiltrated (MI) silicon carbide/silicon carbide (SiC/SiC) ceramic matrix composite (CMC) was investigated at 1200 degrees Celsius in air and in steam. The MI composite consisted of ten 0/90 plies of Hi-Nicalon-S SiC fibers woven in a five harness satin weave (5HSW), a CVI BN interphase to provide a weak fiber-matrix interphase, and a CVI SiC matrix layer followed by infiltration with SiC particulate slurry and molten silicon. Nine tensile specimens of the material were used in a pilot investigation of mechanical performance at elevated temperature. One specimen was used in a monotonic tensile …

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Investigation Of Dynamic Store Separation Out Of A Weapons Bay Cavity Utilizing A Low Speed Wind Tunnel, Andrew D. Bower Mar 2017

Investigation Of Dynamic Store Separation Out Of A Weapons Bay Cavity Utilizing A Low Speed Wind Tunnel, Andrew D. Bower

Theses and Dissertations

Characterizing mission store trajectories as they separate from a weapons bay cavity is highly relevant to the Air Force mission. The flow around a weapons bay is unsteady. The unsteady flow can cause a mission store separation trajectory to be unpredictable, and such is the case for what some have termed a pitch bifurcation. Traditional wind tunnel testing is incapable of detecting a bifurcation because traditional wind tunnel testing records time-averaged data. In this study, an experimental testing system was developed and refined in order to support the time-accurate characterization of dynamic mission store separation events. A Motion Test Apparatus …

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Formation Flight Of Earth Satellites On Kam Torus Using Classical Orbital Elements, Marissa C. Reabe Mar 2017

Formation Flight Of Earth Satellites On Kam Torus Using Classical Orbital Elements, Marissa C. Reabe

Theses and Dissertations

This research uses the KAM theory that has been refined by Wiesel to show that Earth-satellites dynamics can be represented by an integrable Hamiltonian system with a small perturbation, like Earths geopotential. The satellite will follow a torus in phase space and remain on that KAM torus for all time unless acted on by a non-conservative force. A torus frequency was calculated, in this research, using a truth model in System Tool Kit (STK) and the High Precision Orbit Propagator (HPOP) to develop an accurate ephemeris file listing the Classical Orbital Elements (COEs). The frequencies found from the truth model …

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Framework For Industrial Control System Honeypot Network Traffic Generation, Htein A. Lin Mar 2017

Framework For Industrial Control System Honeypot Network Traffic Generation, Htein A. Lin

Theses and Dissertations

Defending critical infrastructure assets is an important but extremely difficult and expensive task. Historically, decoys have been used very effectively to distract attackers and in some cases convince an attacker to reveal their attack strategy. Several researchers have proposed the use of honeypots to protect programmable logic controllers, specifically those used to support critical infrastructure. However, most of these honeypot designs are static systems that wait for a would-be attacker. To be effective, honeypot decoys need to be as realistic as possible. This paper introduces a proof-of-concept honeypot network traffic generator that mimics genuine control systems. Experiments are conducted using …

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A Framework For Categorization Of Industrial Control System Cyber Training Environments, Evan G. Plumley Mar 2017

A Framework For Categorization Of Industrial Control System Cyber Training Environments, Evan G. Plumley

Theses and Dissertations

First responders and professionals in hazardous occupations undergo training and evaluations for the purpose of mitigating risk and damage. For example, helicopter pilots train with multiple categorized simulations that increase in complexity before flying a real aircraft. However in the industrial control cyber incident response domain, where incident response professionals help detect, respond and recover from cyber incidents, no official categorization of training environments exist. To address this gap, this thesis provides a categorization of industrial control training environments based on realism. Four levels of environments are proposed and mapped to Blooms Taxonomy. This categorization will help organizations determine which …

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Applying Cyber Threat Intelligence To Industrial Control Systems, Matthew P. Sibiga Mar 2017

Applying Cyber Threat Intelligence To Industrial Control Systems, Matthew P. Sibiga

Theses and Dissertations

A cybersecurity initiative known as cyber threat intelligence (CTI) has recently been developed and deployed. The overall goal of this new technology is to help protect network infrastructures. Threat intelligence platforms (TIPs) have also been created to help facilitate CTI effectiveness within organizations. There are many benefits that both can achieve within the information technology (IT) sector. The industrial control system (ICS) sector can also benefit from these technologies as most ICS networks are connected to IT networks. CTI and TIPs become resourceful when using indicators of compromise (IOCs) from known ICS malware attacks and an open source intrusion detection …

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On Proportionate And Truthful International Alliance Contributions: An Analysis Of Incentive Compatible Cost Sharing Mechanisms To Burden Sharing, William N. Caballero Mar 2017

On Proportionate And Truthful International Alliance Contributions: An Analysis Of Incentive Compatible Cost Sharing Mechanisms To Burden Sharing, William N. Caballero

Theses and Dissertations

Burden sharing within an international alliance is a contentious topic, especially in the current geopolitical environment, that in practice is generally imposed by a central authority's perception of its members' abilities to contribute. Instead, we propose a cost sharing mechanism such that burden shares are allocated to nations based on their honest declarations of the alliance's worth. Specifically, we develop a set of multiobjective nonlinear optimization problem formulations that respectively impose Bayesian Incentive Compatible (BIC), Strategyproof (SP), and Group Strategyproof (GSP) mechanisms based on probabilistic inspection efforts and deception penalties that are budget balanced and in the core. Any feasible …

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A Scenario-Based Parametric Analysis Of Stable Marriage Approaches To The Army Officer Assignment Problem, Matthew D. Ferguson Mar 2017

A Scenario-Based Parametric Analysis Of Stable Marriage Approaches To The Army Officer Assignment Problem, Matthew D. Ferguson

Theses and Dissertations

This paper compares linear programming and stable marriage approaches to the assignment problem under conditions of uncertainty. Robust solutions should exhibit reduced variability in the presence of one or more additional constraints. Several variations of each approach are compared with respect to solution quality, as measured by the overall social welfare among Officers and Assignments, and robustness as measured by the number of changes after a number of randomized perturbations. We examine the contrasts between these methods in the context of assigning Army Officers among a set of identified assignments. Additional constraints are modeled after realistic scenarios faced by Army …

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Survival Analysis Of Us Air Force Officer Retention Rate, Courtney N. Franzen Mar 2017

Survival Analysis Of Us Air Force Officer Retention Rate, Courtney N. Franzen

Theses and Dissertations

Personnel retention is a matter of great interest in the private and public sectors. In the public sector--specifically the US Air Force--maintaining appropriate retention levels of rated officers is paramount as these officers are the backbone of the Air Force’s mission. As part of the effort to ensure proper retention rates for rated officers, retention models are created by the Air Force Personnel division that assist in predicting future retention patterns and accession needs. The techniques for creating these models, known as the "sustainment line," involve utilizing average retention percentages obtained from historical data. In this study, more statistical-based methods …

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Relating Film Cooling Performance Between Ambient And Near Engine Temperatures, Christopher J. Vorgert Mar 2017

Relating Film Cooling Performance Between Ambient And Near Engine Temperatures, Christopher J. Vorgert

Theses and Dissertations

This thesis explores multiple topics, including the relative importance of nondimensional parameters that relate film cooling performance within different temperature regimes and the effects of internal coolant flow and coolant temperature on overall film cooling effectiveness. A Hastelloy model representative of a turbine blade was utilized for IR tests. Near engine temperatures were produced via premixed propane and air combustion in a Well-Stirred Reactor (WSR) with air supplied as the film coolant gas. Near ambient conditions used heated air for freestream flow and carbon dioxide, argon, or air as film coolant gases. It was found that even with multiple matched …

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Identifying Partnership Opportunities At Air Force Installations: A Geographic Information Systems Approach, Corey R. Degroot Mar 2017

Identifying Partnership Opportunities At Air Force Installations: A Geographic Information Systems Approach, Corey R. Degroot

Theses and Dissertations

The excess capacity found in the Department of Defense real property portfolio creates challenges for leaders to provide resilient installations. Combining this fact with current funding trends makes decisions on how to properly maintain infrastructure even more challenging. The Air Force Partnership Initiative provides tools for installations to leverage community capabilities and resources to achieve savings and improve quality on Air Force installations and can reduce the real property footprint. This research proposes a method for assessing the viability of a partnership between Air Force installations and their nearby communities.
This research effort created a tool capable of investigating off-base …

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Cost Versus Risk: The Policy Of Nuclear Weapon Maintenance Of Tritium Based Limited Life Components, Michael P. Mason Mar 2017

Cost Versus Risk: The Policy Of Nuclear Weapon Maintenance Of Tritium Based Limited Life Components, Michael P. Mason

Theses and Dissertations

This research develops a method to measure the cost to society of current maintenance policy for the exchange of tritium based limited life components within nuclear weapons. The incentives for the Department of Energy and Department of Defense which causes either a substantial cost or substantial risk to be accepted by either Department. A simulation model is created to measure the current policy and compare it to different policies in order to recommend a policy that would minimize the cost to society. The measurement of the cost to society will offer decision makers insight into the ramifications of their decisions.

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Using Markov Decision Processes With Heterogeneous Queueing Systems To Examine Military Medevac Dispatching Policies, Phillip R. Jenkins Mar 2017

Using Markov Decision Processes With Heterogeneous Queueing Systems To Examine Military Medevac Dispatching Policies, Phillip R. Jenkins

Theses and Dissertations

major focus of the Military Health System is to provide efficient and timely medical evacuation (MEDEVAC) to battlefield casualties. Medical planners are responsible for developing dispatching policies that dictate how aerial military MEDEVAC units are utilized during major combat operations. The objective of this research is to determine how to optimally dispatch MEDEVAC units in response to 9-line MEDEVAC requests to maximize MEDEVAC system performance. A discounted, infinite horizon Markov decision process (MDP) model is developed to examine the MEDEVAC dispatching problem. The MDP model allows the dispatching authority to accept, reject, or queue incoming requests based on the request's …

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