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Air Force Institute of Technology

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Articles 361 - 390 of 1238

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

Evaluating Annual Fixed Wing Maintenance Costs, Kirsten Bunecke, Edward D. White, Jonathan D. Ritschel, Brett A. Bush Oct 2018

Evaluating Annual Fixed Wing Maintenance Costs, Kirsten Bunecke, Edward D. White, Jonathan D. Ritschel, Brett A. Bush

Faculty Publications

This article serves two purposes: first, to empirically model the annual percentage increase of operations and support (O&S) costs for fixed wing aircraft; and second, to place into the archival realm another reference for other researchers to consider when investigating other O&S topics. For this study of 21 different airframes grouped together at the Mission- Design Series (MDS), maintenance subcategories 3.1 Consumable Materials and Repair Parts, 3.2 Depot Level Repairables (DLR), and 3.4 Depot Maintenance accounted for an average 91.5% of annual organic maintenance costs. For contractor-maintained MDS, subcategory 3.7, Contractor Logistics Support (CLS) accounted for 96.6% of annual maintenance …

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Operational Squadron Scheduling, Khaled A. Almannaei Sep 2018

Operational Squadron Scheduling, Khaled A. Almannaei

Theses and Dissertations

The 28th Operational Weather Squadron (28th OWS) is responsible for producing and disseminating mission planning and execution weather analyses and forecasts. The squadron must prepare schedules that meet the needs of their mission while dealing with real-world constraints such as time windows, task priorities, and intermittent recurring missions. The 28th OWS's manning consists of active duty, deployed in-place, reserve, civilian and contract personnel. In this research, a scheduling model and algorithm are provided as an approach to crew scheduling for the 28th Operational Weather Squadron. Scheduling in the 28th OWS is complex and can be time consuming. This model will …

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Generating Strong Diversity Of Opinions: Agent Models Of Continuous Opinion Dynamics, Christopher W. Weimer Sep 2018

Generating Strong Diversity Of Opinions: Agent Models Of Continuous Opinion Dynamics, Christopher W. Weimer

Theses and Dissertations

Opinion dynamics is the study of how opinions in a group of individuals change over time. A goal of opinion dynamics modelers has long been to find a social science-based model that generates strong diversity -- smooth, stable, possibly multi-modal distributions of opinions. This research lays the foundations for and develops such a model. First, a taxonomy is developed to precisely describe agent schedules in an opinion dynamics model. The importance of scheduling is shown with applications to generalized forms of two models. Next, the meta-contrast influence field (MIF) model is defined. It is rooted in self-categorization theory and improves …

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The Military Inventory Routing Problem: Utilizing Heuristics Within A Least Squares Temporal Differences Algorithm To Solve A Multiclass Stochastic Inventory Routing Problem With Vehicle Loss, Ethan L. Salgado Sep 2018

The Military Inventory Routing Problem: Utilizing Heuristics Within A Least Squares Temporal Differences Algorithm To Solve A Multiclass Stochastic Inventory Routing Problem With Vehicle Loss, Ethan L. Salgado

Theses and Dissertations

Military commanders currently resupply forward operating bases (FOBs) from a central location within an area of operations mainly via convoy operations in a way that closely resembles vendor managed inventory practices. Commanders must decide when and how much inventory to distribute throughout their area of operations while minimizing soldier risk. Technology currently exists that makes utilizing unmanned cargo aerial vehicles (CUAVs) for resupply an attractive alternative due to the dangers of utilizing convoy operations. Enemy actions in wartime environments pose a significant risk to a CUAV's ability to safely deliver supplies to a FOB. We develop a Markov decision process …

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Methods To Support The Project Selection Problem With Non-Linear Portfolio Objectives, Time Sensitive Objectives, Time Sensitive Resource Constraints, And Modeling Inadequacies, Neil C. Ranly Sep 2018

Methods To Support The Project Selection Problem With Non-Linear Portfolio Objectives, Time Sensitive Objectives, Time Sensitive Resource Constraints, And Modeling Inadequacies, Neil C. Ranly

Theses and Dissertations

The United States Air Force relies upon information production activities to gain insight regarding uncertainties affecting important system configuration and in-mission task execution decisions. Constrained resources that prevent the fulfillment of every information production request, multiple information requestors holding different temporal-sensitive objectives, non-constant marginal value preferences, and information-product aging factors that affect the value-of-information complicate the management of these activities. This dissertation reviews project selection research related to these issues and presents novel methods to address these complications. Quantitative experimentation results demonstrate these methods’ significance.

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Multi-Level Multi-Objective Programming And Optimization For Integrated Air Defense System Disruption, Aaron M. Lessin Sep 2018

Multi-Level Multi-Objective Programming And Optimization For Integrated Air Defense System Disruption, Aaron M. Lessin

Theses and Dissertations

The U.S. military's ability to project military force is being challenged. This research develops and demonstrates the application of three respective sensor location, relocation, and network intrusion models to provide the mathematical basis for the strategic engagement of emerging technologically advanced, highly-mobile, Integrated Air Defense Systems. First, we propose a bilevel mathematical programming model for locating a heterogeneous set of sensors to maximize the minimum exposure of an intruder's penetration path through a defended region. Next, we formulate a multi-objective, bilevel optimization model to relocate surviving sensors to maximize an intruder's minimal expected exposure to traverse a defended border region, …

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Evaluation Criteria For Selecting Nosql Databases In A Single Box Environment, Ryan D. Engle, Brent T. Langhals, Michael R. Grimaila, Douglas D. Hodson Aug 2018

Evaluation Criteria For Selecting Nosql Databases In A Single Box Environment, Ryan D. Engle, Brent T. Langhals, Michael R. Grimaila, Douglas D. Hodson

Faculty Publications

In recent years, NoSQL database systems have become increasingly popular, especially for big data, commercial applications. These systems were designed to overcome the scaling and flexibility limitations plaguing traditional relational database management systems (RDBMSs). Given NoSQL database systems have been typically implemented in large-scale distributed environments serving large numbers of simultaneous users across potentially thousands of geographically separated devices, little consideration has been given to evaluating their value within single-box environments. It is postulated some of the inherent traits of each NoSQL database type may be useful, perhaps even preferable, regardless of scale. Thus, this paper proposes criteria conceived to …

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Likelihood And Cost Impact Of Engineering Change Requirements For Dod Contracts, James C. Ellis, Edward D. White, Jonathan D. Ritschel, Shawn M. Valentine, Brandon Lucas, Ian S. Cordell Apr 2018

Likelihood And Cost Impact Of Engineering Change Requirements For Dod Contracts, James C. Ellis, Edward D. White, Jonathan D. Ritschel, Shawn M. Valentine, Brandon Lucas, Ian S. Cordell

Faculty Publications

Purpose: There appears to be no empirical-based method in the literature for estimating if an engineering change proposal (ECP) will occur or the dollar amount incurred. This paper aims to present an empirically based approach to address this shortfall.
Design/Methodology/Approach: Using the cost assessment data enterprise database, 533 contracts were randomly selected via a stratified sampling plan to build two regression models: one to predict the likelihood of a contract experiencing an ECP and the other to determine the expected median per cent increase in baseline contract cost if an ECP was likely. Both models adopted a stepwise approach. A …

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Case Study: Cooling Channels For Material Testing Applications Using Laser Powder Bed Fusion, Benjamin M. Doane, Ryan P. O'Hara, K. Liu, Carl R. Hartsfield Apr 2018

Case Study: Cooling Channels For Material Testing Applications Using Laser Powder Bed Fusion, Benjamin M. Doane, Ryan P. O'Hara, K. Liu, Carl R. Hartsfield

Faculty Publications

Additive Manufacturing continues to gain a reputation as a key technology that will have a major impact on all aspects of mechanical engineering. The United States Air Force’s (USAF) Air Force Institute of Technology (AFIT), based in Dayton, Ohio, has expanded its AM-focused education and R&D capabilities with the purchase of a Laser Powder Bed Fusion system from Germany’s Concept Laser.

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A System Dynamics Innovation Diffusion Model Applied To Carbon Nanotube Manufacturing, Frances G. Mackinnon Mar 2018

A System Dynamics Innovation Diffusion Model Applied To Carbon Nanotube Manufacturing, Frances G. Mackinnon

Theses and Dissertations

The transition of advanced technologies from their nascent state to viable commercial entities is a critical step in assuring the United States' national technological superiority and support is often required to incubate such technological developments. We propose a spiral development to investigate the possible scenarios, underlying economics, and risk associated with scaling up carbon nanotube (CNT) production to a commercially viable scale. As the first stage of this proposed effort, this study characterizes the potential scenarios by which a CNT manufacturing company can generate positive annual net revenue and potentially be considered a competitive manufacturer of CNT products on an …

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An Analysis Of Major Acquisition Reforms Through Text Mining And Grounded Theory Design, Amanda L. Mcgowin Mar 2018

An Analysis Of Major Acquisition Reforms Through Text Mining And Grounded Theory Design, Amanda L. Mcgowin

Theses and Dissertations

Cost growth is an established phenomenon within Defense Acquisition that the US Government has attempted to abolish for decades through seemingly endless cycles of reform. Dozens of experts and senior leaders within the acquisition community have published their notions on the reasons for cost growth, nevertheless, legislation has yet to eradicate this presumed conundrum. For this reason, this research is aimed at identifying existing trends within past major Defense Acquisition Reform legislation, as well as in a compendium of views from leaders within the Defense Acquisition community on the efficacy of acquisition reform, to determine the possible disconnect. To accomplish …

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Experimental Designs, Meta-Modeling, And Meta-Learning For Mixed-Factor Systems With Large Decision Spaces, Zachary C. Little Mar 2018

Experimental Designs, Meta-Modeling, And Meta-Learning For Mixed-Factor Systems With Large Decision Spaces, Zachary C. Little

Theses and Dissertations

Many Air Force studies require a design and analysis process that can accommodate for the computational challenges associated with complex systems, simulations, and real-world decisions. For systems with large decision spaces and a mixture of continuous, discrete, and categorical factors, nearly orthogonal-and-balanced (NOAB) designs can be used as efficient, representative subsets of all possible design points for system evaluation, where meta-models are then fitted to act as surrogates to system outputs. The mixed-integer linear programming (MILP) formulations used to construct first-order NOAB designs are extended to solve for low correlation between second-order model terms (i.e., two-way interactions and quadratics). The …

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An Open Source Approach To Social Media Data Gathering, Anthony J. Kallhoff Mar 2018

An Open Source Approach To Social Media Data Gathering, Anthony J. Kallhoff

Theses and Dissertations

Modern usage of social media affords the military intelligence and analytic communities novel approaches to gather information. However, the tools and resources to develop these methodologies are still maturing. Furthermore, current data acquisition tools are not available to the DoD for all social media platforms. This thesis addresses a small subset of this problem by developing an open source methodological approach to collect and manage data from a popular social media site that has previously been inaccessible to defense intelligence organizations. This approach was operationalized via the R package called instaExtract, and an exemplar analysis was performed to demonstrate its …

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A Study Of The Air Force Airworthiness Assessment Process With Recommendations For Reusable Launch Vehicles, Austin A. Troya Mar 2018

A Study Of The Air Force Airworthiness Assessment Process With Recommendations For Reusable Launch Vehicles, Austin A. Troya

Theses and Dissertations

Flight safety is a critical design and engineering consideration within the United States Department of Defense (DoD) and particularly the United States Air Force (USAF). This study conducts an independent evaluation of the airworthiness assessment process used by the United States Air Force’s Engineering Directorate through modeling and simulation. The airworthiness process is examined for its ability to effectively verify sound engineering design and efficiency with respect to the implementation of new software-based assessment tools and its impact on timeliness of reviews and resource utilization. Simulation results guide recommendations for reducing non-value-added activities and strategic leveling of resource demands to …

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The Developmental Test Scheduling Problem, Joseph E. Schoenbeck Mar 2018

The Developmental Test Scheduling Problem, Joseph E. Schoenbeck

Theses and Dissertations

Developmental testing of aircraft systems in the United States Air Force requires a complex set of resources for each test. The optimal scheduling of those resources is the job of the 412th Test Wing at Edwards Air Force Base. With more than 20 different Combined Task Forces requesting resources for roughly 300 flying missions each week, manual scheduling is a difficult task. The current process takes a team of schedulers several days to get a workable result from which they can start tailoring the final schedule. While concepts and techniques can be taken from industry scheduling problems, the body of …

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Wavelet Anova Bisection Method For Identifying Simulation Model Bias, Andrew D. Atkinson, Raymond R. Hill, Joseph J. Pignatiello Jr., G. Geoffrey Vining, Edward D. White, Eric Chicken Jan 2018

Wavelet Anova Bisection Method For Identifying Simulation Model Bias, Andrew D. Atkinson, Raymond R. Hill, Joseph J. Pignatiello Jr., G. Geoffrey Vining, Edward D. White, Eric Chicken

Faculty Publications

High-resolution computer models can simulate complex systems and processes in order to evaluate a solution quickly and inexpensively. Many simulation models produce dynamic functional output, such as a set of time-series data generated during a process. These computer models require verification and validation (V&V) to assess the correctness of these simulations. In particular, the model validation effort evaluates if the model is an appropriate representation of the real-world system that it is meant to simulate. However, when assessing a model capable of generating functional output, it is useful to learn more than simply whether the model is valid or invalid. …

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Effect Of Fused Filament Fabrication Process Parameters On The Mechanical Properties Of Carbon Fiber Reinforced Polymers, Abdulrahman S. Alwabel Sep 2017

Effect Of Fused Filament Fabrication Process Parameters On The Mechanical Properties Of Carbon Fiber Reinforced Polymers, Abdulrahman S. Alwabel

Theses and Dissertations

Carbon fiber reinforced polymer manufactured using additive manufacturing process is relatively a new process. The ability to predict the mechanical properties of these parts with high confidence will spread the use of these high-strength materials in more applications. The purpose of this research was to determine the effect of the build time between successive layers, arrangement of fiber and nylon layers, fiber start location, and the use of support material on the mechanical properties CFRP produced by additive manufacturing process using the MarkForged (MarkOne) 3D printer. A design of experiment (DOE) we preformed to develop a mathematical model describing the …

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Evaluating Process Improvement Courses Of Action Through Modeling And Simulation, Joseph R. Owens Sep 2017

Evaluating Process Improvement Courses Of Action Through Modeling And Simulation, Joseph R. Owens

Theses and Dissertations

Quantifying an expected improvement when considering moderate-complexity changes to a process is time consuming and has potential to overlook stochastic effects. By modeling a process as a Numerical Design Structure Matrix (NDSM), simulating the proposed changes, and evaluating performance, quantification can be rapidly accomplished to understand stochastic effects. This thesis explores a method to evaluate complex process changes within Six Sigma DMAIC process improvement to identify the most desirable outcome amongst several improvement options. A tool to perform the modeling and evaluation is developed. This process evaluation tool is verified for functionality, then is demonstrated against generic processes, a case …

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Development And Investigation Of An Air Transportation Operations Safety Climate Scale, Matthew D. Roberts Sep 2017

Development And Investigation Of An Air Transportation Operations Safety Climate Scale, Matthew D. Roberts

Theses and Dissertations

Safety is of critical importance in many industries, and the US Air Force is no exception. Since 2005, the US Air Force has experienced more than 119 on-duty air and ground fatalities as well as 520 off-duty ground fatalities. One of the more dangerous environments in the U.S. Air Force and the civilian industry is air transportation operations where the fatal injury rate is higher than the national average. However, peer-reviewed safety research focusing on air transportation operations is practically non-existent, both in the military and civilian context. Therefore, safety research that helps us better understand how to shape safety …

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Forecasting Us Army Enlistment Contract Production In Complex Geographical Marketing Areas, Joshua L. Mcdonald, Edward D. White, Raymond R. Hill, Christian Pardo Aug 2017

Forecasting Us Army Enlistment Contract Production In Complex Geographical Marketing Areas, Joshua L. Mcdonald, Edward D. White, Raymond R. Hill, Christian Pardo

Faculty Publications

Purpose: The purpose of this paper is to demonstrate an improved method for forecasting the US Army recruiting. Design/methodology/approach: Time series methods, regression modeling, principle components and marketing research are included in this paper. Findings: This paper found the unique ability of multiple statistical methods applied to a forecasting context to consider the effects of inputs that are controlled to some degree by a decision maker. Research limitations/implications: This work will successfully inform the US Army recruiting leadership on how this improved methodology will improve their recruitment process.
Practical implications: Improved US Army analytical technique for forecasting recruiting goals.

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Improving Resource Management In The Afghan Air Force, Jonathan D. Ritschel, Tamiko L. Ritschel Jul 2017

Improving Resource Management In The Afghan Air Force, Jonathan D. Ritschel, Tamiko L. Ritschel

Faculty Publications

The nascent Afghan Air Force (AAF) is rapidly changing with new platforms programmed and existing platforms expanding. As US and coalition forces draw down, the transition of financial responsibility from American to Afghan processes is on the horizon.

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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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Refugees In Urban Environments: Social, Economic, And Infrastructure Impacts, Garrett L. Jameson Mar 2017

Refugees In Urban Environments: Social, Economic, And Infrastructure Impacts, Garrett L. Jameson

Theses and Dissertations

The United Nations High Commissioner for Refugees has estimated that in 2015 there were 21.3 million refugees worldwide; it is estimated that 1.8 million of these persons were newly displaced during 2015. As refugees leave their country to seek the protection of another nation's government, they generally flow into urban areas. The impact of this flow on cities and on the refugees, themselves, is not fully understood. This study is focused on the impact of government policy decisions on the social, legal, and economic integration of refugees within an urban environment. Investigation into this topic resulted in the development of …

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Simulation Modeling And Analysis Of Deployed F-16 Operations And Logistics Support, Gregory D. Potts Ii Mar 2017

Simulation Modeling And Analysis Of Deployed F-16 Operations And Logistics Support, Gregory D. Potts Ii

Theses and Dissertations

The purpose of this thesis is to reinforce and build upon past efforts identifying and demonstrating the need to better represent logistic capabilities and constraints within the realm of wargaming, war planning, and other analyses requiring the modeling of Air Force combat operations. We develop a framework for the porting of relevant logistic information and requirements from a reliable data source (LCOM- ATK) into a discrete event simulation environment (SIMIO), providing a simulation model for enhanced and robust analyses. The simulation we create explicitly reflects (for a selected subset of Work Unit Codes) the maintenance manpower, resources, and parts required …

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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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Multi-Plc Exercise Environments For Training Ics First Responders, Joseph K. Daoud Mar 2017

Multi-Plc Exercise Environments For Training Ics First Responders, Joseph K. Daoud

Theses and Dissertations

When systems are targeted by cyber attacks, cyber first responders must be able to react effectively, especially when dealing with critical infrastructure. Training for cyber first responders is lacking and most existing exercise platforms are expensive, inaccessible or ineffective. This paper presents a mobile training platform which incorporates a variety of programmable logic controllers into a single system which facilitates the development of the unique skills required of cyber first responders operating in the realm of industrial control systems. The platform is modeled after a jail in the northeastern United States and was developed to maximize realism. Example training scenarios …

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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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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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