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Full-Text Articles in Engineering

Application Of Executable Architectures In Early Concept Evaluation, Ryan M. Pospisal Dec 2015

Application Of Executable Architectures In Early Concept Evaluation, Ryan M. Pospisal

Theses and Dissertations

This research explores use of executable architectures to guide design decisions in the early stages of system development. Decisions made early in the system development cycle determine a majority of the total lifecycle costs as well as establish a baseline for long term system performance and thus it is vital to program success to choose favorable design alternatives. The development of a representative architecture followed the Architecture Based Evaluation Process as it provides a logical and systematic order of events to produce an architecture sufficient to document and model operational performance. In order to demonstrate the value in the application …


Collecting Unsolicited User-Generated Change Requests, Joseph W. Goldsmith Dec 2015

Collecting Unsolicited User-Generated Change Requests, Joseph W. Goldsmith

Theses and Dissertations

Unlike aircrew directly associated with acquisitions, line operators are not fully engaged in the methods to push materiel hardware or software change requests up the chain, to a decision maker, and then to the engineers. The Air Force trains these end users to logically apply expert systems knowledge to execute the mission but has not fully leveraged this resource for properly identifying and correcting operational shortfalls in an aircraft's design. Focusing on the Remotely Piloted Aircraft (RPA) community, the research goal is to determine if the Air Force should establish a formal program for collecting and prioritizing unsolicited user change …


Continuous Decision Support, Jeremy P. Hendrix Dec 2015

Continuous Decision Support, Jeremy P. Hendrix

Theses and Dissertations

Organizations are often faced with portfolio construction efforts that require them to select one or more alternatives, subject to resource constraints, with the aim of achieving the maximum value possible. This is a well-defined problem with a number of analytically defensible approaches, provided the entire set of alternatives is known when the decision event takes place. Less well treated in the literature is how to approach this problem when the entire set of alternatives is unknown, as when the alternatives arrive over time. This change in the availability of data shifts the problem from one of identifying an optimal subset …


Predicting Public Bicycle Adoption Using The Technology Acceptance Model, Benjamin T. Hazen, Robert E. Overstreet, Yacan Wang Nov 2015

Predicting Public Bicycle Adoption Using The Technology Acceptance Model, Benjamin T. Hazen, Robert E. Overstreet, Yacan Wang

Faculty Publications

Bicycle sharing programs provide a sustainable mode of urban transportation. Although cities across the globe have developed these systems for their citizens and visitors, usage rates are not as high as anticipated. This research uses the technology acceptance model as the basis to understand one’s intention to adopt bicycle sharing programs. Using survey data derived from 421 participants in Beijing, China, the proposed covariance-based structural equation model consisting of perceived quality, perceived convenience, and perceived value is found to predict 50.5% of the variance in adoption intention. The findings of this research contribute to theory and practice in the burgeoning …


Integrated Systems Health Management As An Enabler For Condition Based Maintenance And Autonomic Logistics, Robert M. Vandawalker Sep 2015

Integrated Systems Health Management As An Enabler For Condition Based Maintenance And Autonomic Logistics, Robert M. Vandawalker

Theses and Dissertations

Health monitoring systems have demonstrated the ability to detect potential failures in components and predict how long until a critical failure is likely to occur. Implementing these systems on fielded structures, aircraft, or other vehicles is often a struggle to prove cost savings or operational improvements beyond improved safety. A system architecture to identify how the health monitoring systems are integrated into fielded aircraft is developed to assess cost, operations, maintenance, and logistics trade-spaces. The efficiency of a health monitoring system is examined for impacts to the operation of a squadron of cargo aircraft revealing sensitivity to and tolerance for …


Grabbing The Air Force By The Tail: Applying Strategic Cost Analytics To Understand And Manage Indirect Cost Behavior, Bradley C. Boehmke Sep 2015

Grabbing The Air Force By The Tail: Applying Strategic Cost Analytics To Understand And Manage Indirect Cost Behavior, Bradley C. Boehmke

Theses and Dissertations

Recent and projected reductions in defense spending are forcing the military services to develop systematic approaches to identify cost reduction opportunities and better manage financial resources. In response, the Air Force along with her sister services are developing strategic approaches to reduce front-line mission resources, commonly referred to as the Tooth . However, an underemphasized contributing source of costs are mission support activities, commonly referred to as the Tail . With the tail historically representing a sizable portion of the annual Air Force budget, strategically managing cost behavior of these indirect activities has the opportunity to generate significant cost reductions. …


Supply Chain Interoperability Measurement, Christos E. Chalyvidis Jun 2015

Supply Chain Interoperability Measurement, Christos E. Chalyvidis

Theses and Dissertations

Academia recognizes that although supply chains have an inherent need to be validated for their performance, supply chain performance measurement systems are still inadequate and one of the major barriers to successful supply chain collaboration. In this research, theory of Systems Architecture is used to make the first step towards an innovative supply chain performance measure defined as supply chain interoperability. Interoperability is considered a similarity metric with regard to a set of deterministic and stochastic characters (criteria) describing supply chain participants, a methodology that adapts and expands an interoperability measurement tool initially developed in and for a military context. …


A Method To Predict Compressor Stall In The Tf34-100 Turbofan Engine Utilizing Real-Time Performance Data, Shuxiang A. Li, Trevor G. Jones Jun 2015

A Method To Predict Compressor Stall In The Tf34-100 Turbofan Engine Utilizing Real-Time Performance Data, Shuxiang A. Li, Trevor G. Jones

Theses and Dissertations

The Air Force current operations continue to undergo significant changes compelled by decreasing fiscal appropriations, aging aircraft, and personnel drawdown. The Air Force must effectively improve current maintenance operations in part to deal with these challenges. This study will explore the area of the A-10 aircraft fleet's TF34-100 high-pass turbo-fan engine sensor data to seek its deterioration modelling and prognostics capability. In futurity this will allow for achievement of greater confidence in predicting the compressor stall which leads to engine performance deterioration and a costly repair in maintenance. By utilizing an innovative method to forecast the probability of compressor stall, …


An Assessment Of The Effectiveness Of Air Force Risk Management Practices In Program Acquisition Using Survey Instrument Analysis, Michael J. Maroney Jr. Jun 2015

An Assessment Of The Effectiveness Of Air Force Risk Management Practices In Program Acquisition Using Survey Instrument Analysis, Michael J. Maroney Jr.

Theses and Dissertations

Air Force acquisition programs invest a large amount of resources to develop and field systems. Many of these resources go to risk management in order to help ensure those programs finish successfully with respect to cost, schedule, and technical performance goals. The question arises as to whether this is a sound investment. Although risk management has been shown to be effective in industry, scant empirical evidence exists for its effectiveness within the Air Force. Correlation and regression analysis of survey data show that a positive relationship does exist between specific risk practices and project success. Furthermore, the analysis suggests that …


Analysis Of The Effectiveness Of The F-15e Risk Management During Peacetime Operations, Elliot B. Vasquez Jun 2015

Analysis Of The Effectiveness Of The F-15e Risk Management During Peacetime Operations, Elliot B. Vasquez

Theses and Dissertations

Human factors are causal or contributory in 80% of Class A mishaps in the Air Force. Risk management tools are used throughout the service in every aircraft to help mitigate the risk of those human factors occurring. The F-15E Strike Eagle community was selected for analysis on the effectiveness of its risk management program but the data was comprised on Class A mishaps from Accident Investigation Boards since 2000 between the F-15 (all models), F-16 (all models), and F-22. Cases were selected if there were human factors root causes or contributory. A fault tree analysis coupled with the Department of …


Impact Of Prognostic Uncertainty In System Health Monitoring, Robert M. Vandawalker, David R. Jacques, Jason K. Freels May 2015

Impact Of Prognostic Uncertainty In System Health Monitoring, Robert M. Vandawalker, David R. Jacques, Jason K. Freels

Faculty Publications

Across many industries, systems are exceeding their intended design lives, whether they are ships, bridges or military aircraft. As a result failure rates can increase and unanticipated wear or failure conditions can arise. Health monitoring research and application has the potential to more safely lengthen the service life of a range of systems through utilization of sensor data and knowledge of failure mechanisms to predict component life remaining. A further benefit of health monitoring when combined across an entire platform is system health management. System health management is an enabler of condition based maintenance, which allows repair or replacement based …


A Predictive Logistic Regression Model Of World Conflict Using Open Source Data, Benjamin C. Boekestein Mar 2015

A Predictive Logistic Regression Model Of World Conflict Using Open Source Data, Benjamin C. Boekestein

Theses and Dissertations

Nations transitioning into conflict is an issue of national interest. This study considers various data for inclusion in a statistical model that predicts the future state of the world where nations will either be in a state of violent conflict or not in violent conflict based on available historical data. Logistic regression is used to construct and test various models to produce a parsimonious world model with 15 variables. Further analysis shows that nations differ significantly by geographical area. Therefore six sub-models are constructed for differing geographical areas of the world. The dominant variables for each sub-model vary, suggesting a …


Overcoming Hurdles Implementing Multi-Skilling Policies, Joshua M. Isom Mar 2015

Overcoming Hurdles Implementing Multi-Skilling Policies, Joshua M. Isom

Theses and Dissertations

Ogden ALC at Hill AFB has been authorized to promote wage grade employees if they are multi-skilled, but that authorization will expire at the end of Fiscal Year 2018. Simulation research by Capt Wesley Sheppard demonstrated significant cost savings/cost avoidance if multi-skilling is pursued, but there are significant challenges to implementation. This research examined two challenges in implementation. First, how many employees can be multi-skilled and still maintain proficiency in both skills? Second, once multi-skilled, is there a technique that can be applied to easily and effectively schedule the new multi-skilled workforce. Using linear programming, staffing numbers were calculated based …


The Brazilian Air Force Uniform Distribution Process: Using Lean Thinking, Statistical Process Control And Theory Of Constraints To Address Improvement Opportunities, Luciano A. Dos Santos Mar 2015

The Brazilian Air Force Uniform Distribution Process: Using Lean Thinking, Statistical Process Control And Theory Of Constraints To Address Improvement Opportunities, Luciano A. Dos Santos

Theses and Dissertations

In the Brazilian Air Force, all enlisted Soldiers and Corporals (corresponding to USAF ranks from Airman Basic to Senior Airman) are entitled to receive their uniforms from their assigned, respective organizations, free of charge. An important portion of the uniform s distribution process is accomplished by the Brazilian Air Force Intendancy Central Depot (ICD). This organization carries the uniform inventory and performs the selection and distribution activities, following the guidance of the Sub-directorate of Supply. ICD process performance data for the peak distribution seasons of 2012 and 2013 was collected and analyzed. Several indications of inefficiencies became apparent, exemplified by …


Active Duty C-17 Aircraft Commander Fuel Efficiency Metrics And Goal Evaluation, Michael J. Schumacher Mar 2015

Active Duty C-17 Aircraft Commander Fuel Efficiency Metrics And Goal Evaluation, Michael J. Schumacher

Theses and Dissertations

As the largest consumer of fuel in the Department of Defense, the Air Force continually looks for new ways to advocate aircraft fuel efficiency. Optimal metrics and goals are essential components to encourage efficient flying. This research examined two metrics through quantitative statistical and qualitative criteria analysis, picked the most effective metric, and utilized Goal Setting Theory (GST) to couple the metric with an attainable goal aimed at making Aircraft Commander's (AC's) more fuel efficient. The first metric, M1Cargo Adjusted, uses current sortie planning factors and adjusts these for payload. The second metric, M2Regression, uses regression analysis based on flight …


Value Focused Thinking Applications To Supervised Pattern Classification With Extensions To Hyperspectral Anomaly Detection Algorithms, David S. Scanland Mar 2015

Value Focused Thinking Applications To Supervised Pattern Classification With Extensions To Hyperspectral Anomaly Detection Algorithms, David S. Scanland

Theses and Dissertations

Hyperspectral imaging (HSI) is an emerging analytical tool with flexible applications in different target detection and classification environments, including Military Intelligence, environmental conservation, etc. Algorithms are being developed at a rapid rate, solving various related detection problems under certain assumptions. At the core of these algorithms is the concept of supervised pattern classification, which trains an algorithm to data with enough generalizability that it can be applied to multiple instances of data. It is necessary to develop a logical methodology that can weigh responses and provide an output value that can help determine an optimum algorithm. This research focuses on …


Non-Rated Air Force Line Officer Attrition Rates Using Survival Analysis, Jill A. Schofield Mar 2015

Non-Rated Air Force Line Officer Attrition Rates Using Survival Analysis, Jill A. Schofield

Theses and Dissertations

The Air Force structures its workforce around rank structure and work specialty codes (Air Force Specialty Codes (AFSCs)). The challenge is to grow and manage personnel to fill a variety of skill sets at a variety of ranks over a 20-30 year planning horizon. To ensure that the missions are accomplished while adhering to congressionally-mandated force allocations, the Air Force is continually attempting to \right size its force by maintaining the correct balance of personnel in each career field. The Air Force conducts its force structure management responsibility by comparing historical attrition rates to current manpower requirements for each AFSC …


Statistical Observations Of Positioning, Navigation, And Timing In A Combat Simulation, Matthew G. Thomas Mar 2015

Statistical Observations Of Positioning, Navigation, And Timing In A Combat Simulation, Matthew G. Thomas

Theses and Dissertations

The Global Positioning System (GPS) has become an important asset in the lives of civilians and defense organizations. GPS uses include positioning, navigation, timing, as well as many other daily applications. With such dependence, protection against attacks on the system is paramount to continue its effectiveness. Attacks on its signal is the easiest way for enemies to degrade and harm not only everyday functioning for civilians, but a nation's defense as well. Jamming interference and spoofing are the two most frequent attacks on GPS signals. Could these two attacks cause significant effect on military operations? We use a System Effectiveness …


Functionality, Complexity, And Approaches To Assessment Of Resilience Under Constrained Energy And Information, Jason B. Clark Mar 2015

Functionality, Complexity, And Approaches To Assessment Of Resilience Under Constrained Energy And Information, Jason B. Clark

Theses and Dissertations

While system functions, functionality, and complexity are widely used concepts in systems engineering, there is significant diversity in their definitions and no unified approach to measurement. This research establishes a method for measuring impacts to functionality in dynamic engineered systems based on changes in kinetic energy. This metric is applied at particular levels of abstraction and system scales, consistent with the established multiscale nature of systems. By measuring system behavior in context with expected scenarios, it is possible to estimate expected functionality or set bounds on a system's maximum functionality. Functionality and system effectiveness is heavily influenced by the amount …


Using Earned Value Data To Forecast The Duration Of Department Of Defense (Dod) Space Acquisition Programs, Shedrick M. Bridgeforth Mar 2015

Using Earned Value Data To Forecast The Duration Of Department Of Defense (Dod) Space Acquisition Programs, Shedrick M. Bridgeforth

Theses and Dissertations

The accuracy of cost estimates is vital during this era of budget constraints. A key component of this accuracy is regularly updating the cost estimate at completion (EAC). A 2014 study by the Air Force Cost Analysis Agency (AFCAA) improved the accuracy of the cost estimate at completion (EAC) for space system contracts. The study found schedule duration to be a cost driver, but assumed the underlying duration estimate was accurate. This research attempts to improve the accuracy of the duration estimate from the AFCAA study; accuracy is evaluated with the Mean Absolute Percent Error (MAPE). The methods researched here …


Modeling, Simulation, And Analysis Of A Decoy State Enabled Quantum Key Distribution System, Ryan D. Engle Mar 2015

Modeling, Simulation, And Analysis Of A Decoy State Enabled Quantum Key Distribution System, Ryan D. Engle

Theses and Dissertations

Quantum Key Distribution (QKD) is an emerging technology which uses the principles of quantum mechanics to provide unconditionally secure key distribution. QKD systems are unique in their ability to detect an eavesdropper's presence and are being marketed for applications where high levels of secrecy are required such as banking, government, and military environments. QKD systems are composed of electrical, optical, and electrooptical components. Their design requires expertise across multiple disciplines including computer science, computer engineering, electrical engineering, information theory, optical physics, and quantum physics. This multidisciplinary nature makes QKD an ideal candidate for study using Model Based Systems Engineering (MBSE) …


Parametric Estimation Of Load For Air Force Datacenters, Derek P. Molle Mar 2015

Parametric Estimation Of Load For Air Force Datacenters, Derek P. Molle

Theses and Dissertations

The Office of Management and Budget (OMB) has tasked Federal agencies to develop a Data Center Consolidation Plan. Effective planning requires a repeatable method to effectively and efficiently size Air Force Base-level data centers. Review of commercial literature on data center design found emphasis in power efficiency, thermal modeling and cooling, and network speed and availability. The topic of sizing data center processing capacity seems undeveloped. This thesis provides a better, pedigreed solution to the data center sizing problem. By analogy, Erlang's formulae for the probability of blocking and queuing should be applicable to cumulative CPU utilization in a data …


A Comparative Study Of Learning Curve Models In Defense Airframe Cost Estimating, Justin R. Moore Mar 2015

A Comparative Study Of Learning Curve Models In Defense Airframe Cost Estimating, Justin R. Moore

Theses and Dissertations

The goal of this research was to identify which learning curve model is most accurate when applied to Defense acquisition programs. Wright's original learning curve model is widely accepted and used within Defense acquisitions, but the 75+ year old model may be outdated. This study compares Wright's model against three alternative learning curve models using total lot costs for the F-15 C/D & E programs: the Stanford-B model, the DeJong learning formula, and the S-Curve model. However, the results of the study are inconclusive. Two of the three alternative models, the DeJong and S-Curve, rely on the use of an …


Pragmatic Divestment Of Kc-135 Navigators In The Special Operations Air Refueling Mission, Andrew P. Nation Mar 2015

Pragmatic Divestment Of Kc-135 Navigators In The Special Operations Air Refueling Mission, Andrew P. Nation

Theses and Dissertations

In the late 1990s, the Air Force eliminated over 200 KC-135 navigators, leaving 50 remaining for the aircraft's most complex Special Operations Air Refueling (SOAR) mission. As the Air Force unveils the KC-46 Pegasus, this mission will continue but without a position for the navigator. Instead, navigators will undergo divestment as the SOAR mission transfers to the KC-46. Current plans indicate navigators will not only remain as the KC-46 arrives, but inbound navigators will continue arriving until 2018. This thesis applies the Delphi method, a process eliciting analysis anonymously from a panel of experts, in order to examine the elements …


Army Information Technology Procurement: A Business Process Analysis, Alexander M. Vukcevic Mar 2015

Army Information Technology Procurement: A Business Process Analysis, Alexander M. Vukcevic

Theses and Dissertations

This thesis presents a business process analysis of the Army's ICT procurement system. The research identified several inefficiencies and proposes several potential solutions. the contributions of this research include a unified taxonomy, a method to prioritize requests, and system architecture products for development of an automated and sustainable collaboration interface for the CIO/G6 to streamline their IT acquisition process. Development of a centralized system would reduce waste in the request process from submission to formal accounting, hasten the movement of requests between stakeholders, maintain a digital signature authorization for each approval authority, provide a reporting database to recognize reprogramming thresholds, …


Toward Agent-Based Modeling Of The U.S. Department Of Defense Acquisition System, Karl Schwenn, John M. Colombi, Theresa Wu, Kyle F. Oyama, Alan W. Johnson Mar 2015

Toward Agent-Based Modeling Of The U.S. Department Of Defense Acquisition System, Karl Schwenn, John M. Colombi, Theresa Wu, Kyle F. Oyama, Alan W. Johnson

Faculty Publications

The systems development, procurement and sustainment of a nation's military equipment is vital to its national interests, but the process is complex, constantly changing and highly adaptive, as well as time consuming and costly. The U.S. Department of Defense (DoD) expends both large amounts of capital and manpower to equip its armed forces. This research seeks to identify opportunities to gain better insight into the functioning of the defense acquisition system, building on previous simulations. A case is made that the DoD Requirements, Planning Acquisition, Technology and Logistics System is a complex adaptive system that has characteristics appropriate for exploration …