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Articles 301 - 330 of 1292

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

Wavelet Methods For Very-Short Term Forecasting Of Functional Time Series, Jared K. Nystrom Sep 2021

Wavelet Methods For Very-Short Term Forecasting Of Functional Time Series, Jared K. Nystrom

Theses and Dissertations

Space launch operations at Kennedy Space Center and Cape Canaveral Space Force Station (KSC/CCSFS) are complicated by unique requirements for near-real time determination of risk from lightning. Lightning forecast weather sensor networks produce data that are noisy, high volume, and high frequency time series for which traditional forecasting methods are often ill-suited. Current approaches result in significant residual uncertainties and consequentially may result in forecasting operational policies that are excessively conservative or inefficient. This work proposes a new methodology of wavelet-enabled semiparametric modeling to develop accurate and timely forecasts robust against chaotic functional data. Wavelets methods are first used to …

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Collaborative All-Source Navigation With Integrity, Jonathon S. Gipson Sep 2021

Collaborative All-Source Navigation With Integrity, Jonathon S. Gipson

Theses and Dissertations

The novel ARMAS-SOM framework fuses collaborative all-source sensor information in a resilient manner with fault detection, exclusion, and integrity solutions recognizable to a GNSS user. This framework uses a multi-filter residual monitoring approach for fault detection and exclusion and is augmented with an additional "observability" EKF sub-layer for resilience. We monitor the a posteriori state covariances in this sub-layer to provide intrinsic awareness when navigation state observability assumptions required for integrity are in danger. This is used to selectively augment the framework with offboard information to preserve resilience. By maintaining split parallel collaborative and proprioceptive estimation instances and employing a …

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Interdependent Infrastructure Recovery Using Multilayered Networks And Optimization, Brigham A. Moore Sep 2021

Interdependent Infrastructure Recovery Using Multilayered Networks And Optimization, Brigham A. Moore

Theses and Dissertations

Interdependent infrastructure recovery modeling and simulation are complicated due to various interdependent connections and complexities. Current efforts have identified both operational and restoration interdependency subtypes and coupling strategies that have not been integrated into one comprehensive model. This research presents a model which simultaneously integrates nine interdependency subtypes and four coupling strategies in a multi-objective format to provide the most tailorable and comprehensive network-based recovery model available. This research also created a defense-centric interdependent infrastructure database by modifying the existing CLARC database. This research then addressed assumptions regarding recovery work management in order to address the impact of work crew …

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Applying Model-Based Systems Engineering And Fidelity Quantification To Support Fair Fight In A Distributed Simulation System, Nathaniel Erbe, David Lemmer Sep 2021

Applying Model-Based Systems Engineering And Fidelity Quantification To Support Fair Fight In A Distributed Simulation System, Nathaniel Erbe, David Lemmer

Theses and Dissertations

Current 5th and 6th generation fighter aircraft capabilities, and the DoD's push towards digital engineering have created an environment in which simulated testing using live, virtual, and constructive assets has increasing utility. These simulations need to be credible in the eyes of the stakeholders, which for distributed simulation systems includes establishing fair fight between simulation services. Fair fight is when multiple simulations interoperate without generating one-sided systematic advantages. Issues that impede fair fight can be categorized into interoperability issues at the simulations implementation level and incompatible representations of reality between underlying models. This research used model-based systems engineering to generate …

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Requirements Analysis And Architecture For An Operational Study Of Fatigue In Usaf Mobility Aircrew, Jonathan F. Mecham Sep 2021

Requirements Analysis And Architecture For An Operational Study Of Fatigue In Usaf Mobility Aircrew, Jonathan F. Mecham

Theses and Dissertations

Aircrew fatigue in flight operations is a known hazard that has driven the creation of fatigue-reducing regulation and fatigue risk management systems industry wide. In addition, biomathematical models have been created and tested to forecast the effectiveness of aircrew under conditions of time-zone shifts and long duty days. However, limited operational studies exist to validate these models or to help understand how individual factors can affect them. Operational studies have a variety of limitations that make gathering typical data regarding fatigue or sleep difficult. This research takes systems requirement analysis approach to design a study that measures effects of circadian …

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Performance Improvement Through Better Understanding Of Supply Chain Resilience, Amanda L. Femano Sep 2021

Performance Improvement Through Better Understanding Of Supply Chain Resilience, Amanda L. Femano

Theses and Dissertations

Businesses operate every day in a disruptive environment. Supply and demand uncertainty, natural disasters, global pandemics, and mishaps can all cause chaos to a supply chain’s flow. It is impossible to predict every disruption a supply chain may encounter. The best an organization can do to protect network performance is to build resilience in the supply chain and life-blood of its operations. Ensuring that a supply chain has the proper built-in mechanisms to resist and recover from disruptions is referred to as Supply Chain Resilience (SCR). While it is generally agreed that SCR can be improved through the implementation of …

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Examining The Influence Of Source Dependence On Supplier Performance In The Usaf Organic Supply Chain, Thomas A. Counter Jun 2021

Examining The Influence Of Source Dependence On Supplier Performance In The Usaf Organic Supply Chain, Thomas A. Counter

Theses and Dissertations

The purpose of this study is to examine the U.S. Air Force's dependence toward sole sourcing and how that influences procurement outcomes in terms of supplier performance. This research used linear regression to explain the effect of source dependence and supplier size on performance categories for 326 suppliers. The five supplier performance categories in the study included timeliness, cost control, quality, business relations, and regulatory compliance. The research found that the USAFs dependence on sole sourcing had a small but statistically significant influence on all five aspects of supplier performance, with timeliness being the most adversely impacted.

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Developing A Basic Formal Supply Chain Ontology To Improve Communication And Interoperability, David Morrow Jun 2021

Developing A Basic Formal Supply Chain Ontology To Improve Communication And Interoperability, David Morrow

Theses and Dissertations

Information is crucial to supply chain performance because it is used to make decisions and trigger actions. Organizations across world-class supply chains increasingly use information technology to analyze and process supply chain data. However, supply chain management lacks a common language, making information exchange difficult. An ontology can provide a standardized framework that organizes a given knowledge domain. This research proposes a common language for developing a supply chain ontology that can be built into a basic formal ontology understood by both humans and computers. According to current research, an established and widely used supply chain framework is a good …

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Statistically Defensible Wind Tunnel Models, Timothy A. Roche Jun 2021

Statistically Defensible Wind Tunnel Models, Timothy A. Roche

Theses and Dissertations

Wind tunnels are used to test scale-model air frames in order to collect aerodynamic data. The Subsonic Aerodynamic Research Laboratory (SARL) Wind Tunnel is a low speed wind tunnel located at Wright-Patterson Air Force Base. The SARL Wind Tunnel team approached AFIT for assistance in creating statistically defensible models for the conditions inside the wind tunnel. During a wind tunnel test, pressure sensors cannot be placed at the test model. Instead, pressure is measured by a pitot probe permanently mounted in the corner of the test chamber. The pressure at the model location is predicted from the measurements taken by …

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Design And Sensitivity Analysis Of Blood Supply Chain Network, The Merits Of Lateral Resupply, Mohammad Arani May 2021

Design And Sensitivity Analysis Of Blood Supply Chain Network, The Merits Of Lateral Resupply, Mohammad Arani

Theses and Dissertations

The vibrant subject of blood banking and blood distribution is addressed where lateral resupply of blood products is allowed. In this research, a blood supply chain network design (BSCND) consisting of four conventional levels each of which corresponding to one entity in the real world is comprehensively studied: donors, blood collection facilities, blood centers, and hospitals. Two important properties are considered within the blood supply chain network (BSCN): ABO-Rh factors and shelf lives of blood products. Moreover, an integrated inventory system for sharing hospitals’ inventory levels is designed to investigate the two performance indicators of the network in terms of …

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An Analysis Of Application Type, Super Domain, And Productivity In Software Intensive Defense Acquisition, Evan P. Amato Mar 2021

An Analysis Of Application Type, Super Domain, And Productivity In Software Intensive Defense Acquisition, Evan P. Amato

Theses and Dissertations

The productivity of software developers has been an area of interest in the private industry in an endeavor to more appropriately interpret pertinent software development cost drivers. In an effort to better predict the cost of developing software, many have focused on Application Type as an important factor. The Department of Defense (DoD) has recently adopted a similar focus. Studies on categorization schemes of Application Types have shown increasingly relevant cost and productivity driving characteristics recently in the DoD. Identification of factors associated with distinct productivity effects is important for the defense acquisition and software cost estimation domains. Distinct factors …

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Strategic Upgrade Scheduling And Portfolio Management To Fortify Contested Networks, Justin L. Anderson Mar 2021

Strategic Upgrade Scheduling And Portfolio Management To Fortify Contested Networks, Justin L. Anderson

Theses and Dissertations

The nuclear command, control, and communication (NC3) network provides an effective deterrent against adversaries by maintaining robust communication between assets, operators, and decision makers. NC3 must receive a series of upgrades to remain an effective deterrent against evolving threats around the globe. Given a contested network and a portfolio of network upgrades, this research seeks an optimal upgrade schedule to maximize network resilience in support of NC3 modernization. Our research contributes a model that solves a budget-constrained network upgrade scheduling problem (NUSP). The NUSP is a defender-attacker-defender tri-level optimization model that achieves fortification via selecting and scheduling network upgrades. The …

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Reducing Military Personnel Flight Wait Times Using A Simulation, Matthew D. Cornman Mar 2021

Reducing Military Personnel Flight Wait Times Using A Simulation, Matthew D. Cornman

Theses and Dissertations

A shortage of resources and system failures have put a strain on Military Personnel Flights (MPFs) being able to service their customers in a timely manner. Prolonged customer wait times are becoming a common problem in most MPFs creating problems between the relationship of the customers and leadership. This research uses historical data of an MPF to develop a simulation model of daily operations in an MPF. Subject matter expertise of current MPF operations and resource levels were used to provide a baseline model of the MPF queuing system. The analysis examines the effects of number of Defense Enrollment Eligibility …

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Predicting F-16 Cause Code H Micap Hours Using Jmp Regression Analysis, Scott E. Carr Mar 2021

Predicting F-16 Cause Code H Micap Hours Using Jmp Regression Analysis, Scott E. Carr

Theses and Dissertations

Emergency demands for aircraft parts, MICAPs (Mission Impaired Capability Awaiting Parts) are one of the leading issues affecting mission capability supply rates for fighter aircraft. Cause code H MICAPS, those with a known demand level, but no supply available, are particularly troublesome and difficult to resolve. These MICAPS are due to failures by the supply chain to replenish stock levels within acceptable time limits. Numerous studies have identified a clear need for proactive measures to reduce MICAP hours. This would significantly improve aircraft availability. This study uses regression analysis implemented in JMP software to build models with a goal of …

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Air Combat Maneuvering Via Operations Research And Artificial Intelligence Methods, James B. Crumpacker Mar 2021

Air Combat Maneuvering Via Operations Research And Artificial Intelligence Methods, James B. Crumpacker

Theses and Dissertations

Within visual range air combat requires rapid, sequential decision-making to survive and defeat the adversary. Fighter pilots spend years perfecting maneuvers for these types of engagements, yet the emergence of unmanned, autonomous vehicle technologies elicits a natural question - can an autonomous unmanned combat aerial vehicle (AUCAV) be imbued with the necessary artificial intelligence to perform air combat maneuvering tasks independently? We formulate and solve the air combat maneuvering problem to examine this question, developing a Markov decision process model to control an AUCAV seeking to destroy a maneuvering adversarial vehicle. An approximate dynamic programming (ADP) approach implementing neural network …

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Exploring The Limits Of Strategic Thought: Evaluating How Different Communication Modalities Affect The Nature Of Strategic Decision-Making Using Cognitive Hierarchy, Stephen D. Donnel Mar 2021

Exploring The Limits Of Strategic Thought: Evaluating How Different Communication Modalities Affect The Nature Of Strategic Decision-Making Using Cognitive Hierarchy, Stephen D. Donnel

Theses and Dissertations

This research examines and quantifies the degree to which both information communication modality and the situational complexity affect individuals' ability to process the provided information and determine an effective strategy. Human subject testing herein consists of benign benevolent intervention involving the presentation of a series of strategic situations. For each situation, a participant attempts to identify their best response for a two-player, normal-form game with complete information. In each such game, players seek to maximize their own utility while considering their own actions, their opponent's actions, and each player's respective preferences over outcomes resulting from the possible combinations of actions. …

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An Examination Of Potential Training Regression Recognition Algorithms For Pilot Training Next, Alex R. Gaines Mar 2021

An Examination Of Potential Training Regression Recognition Algorithms For Pilot Training Next, Alex R. Gaines

Theses and Dissertations

The initiative to reduce the Air Forces serious pilot shortage lead to the Pilot Training Next (PTN) program. Under PTN, student pilots progress at an individual rate while making increased use of simulator-based training resources. A previous thesis used data from the first PTN class to conceptualize and prototype a student training flight scheduler. This scheduler did not consider training events required to bring students back to achieved levels of performance if in fact that student performance had regressed. This thesis examines three classes of PTN student data to determine whether student regression in training progression can be detected. A …

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The Autonomous Attack Aviation Problem, John C. Goodwill Mar 2021

The Autonomous Attack Aviation Problem, John C. Goodwill

Theses and Dissertations

An autonomous unmanned combat aerial vehicle (AUCAV) performing an air-to-ground attack mission must make sequential targeting and routing decisions under uncertainty. We formulate a Markov decision process model of this autonomous attack aviation problem (A3P) and solve it using an approximate dynamic programming (ADP) approach. We develop an approximate policy iteration algorithm that implements a least squares temporal difference learning mechanism to solve the A3P. Basis functions are developed and tested for application within the ADP algorithm. The ADP policy is compared to a benchmark policy, the DROP policy, which is determined by repeatedly solving a deterministic orienteering problem as …

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The Impact Of Triage Classification Errors On Military Medical Evacuation System Performance, Emily S. Graves Mar 2021

The Impact Of Triage Classification Errors On Military Medical Evacuation System Performance, Emily S. Graves

Theses and Dissertations

In a deployed environment, evacuation requests of injured personnel are serviced by multiple forms of evacuation including medical evacuation (MEDEVAC) and casualty evacuation (CASEVAC). This thesis focuses on the optimal dispatching policy for MEDEVAC units when triage classification errors and blood transfusion kits are considered. A discounted, infinite-horizon Markov decision process (MDP) model is formulated to analyze the MEDEVAC dispatching problem and determine the optimal policy based on the status of the MEDEVAC units in the system, the priority level of incoming requests, and the locations from which requests originate. A notional, representational scenario based in Azerbaijan is utilized to …

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Automated Sentiment Analysis For Personnel Survey Data In The Us Air Force Context, Julia M. Haines Mar 2021

Automated Sentiment Analysis For Personnel Survey Data In The Us Air Force Context, Julia M. Haines

Theses and Dissertations

When surveys are distributed across the Air Force (AF), whether it be an employee engagement survey, a climate survey, or similar, significant resources are put towards the development, distribution and analysis of the survey. However, when open ended questions are included on these surveys, respondent comments are generally underutilized, more often treated as a source for pull-quotes rather than a data source in and of themselves. This is due to a lack of transparency and confidence in the accuracy of machine-aided methods such as sentiment analysis and topic modeling. This confidence reduces further when the text has special context, such …

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Allocation Of Scarce Healthcare Resources In A Military Treatment Facility During A Pandemic: A Comparison Of Goal Programming And Portfolio Decision Analysis Methods, Donald B. Hale Mar 2021

Allocation Of Scarce Healthcare Resources In A Military Treatment Facility During A Pandemic: A Comparison Of Goal Programming And Portfolio Decision Analysis Methods, Donald B. Hale

Theses and Dissertations

In a pandemic, healthcare decisionmakers face the challenge of allocating critical, but scarce healthcare resources in a dynamic, uncertain environment. Their decisions will not only affect the patients coming to the hospital for treatment, but also the Military Treatment Facility's personnel responsible. The decisionmaker must decide how to allocate these resources to achieve multiple, conflicting objectives under multiple constraints. In response, we propose a methodology for the implementation of both Portfolio Decision Analysis and Goal Programming. The steps of this methodology provide a framework with which the decisionmaker can develop optimal allocation of resources. This framework was then applied to …

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Ccsfs/Ksc Total Lightning Warning Radii Optimization For Merlin Using Preexisting Lightning Areas, Kimberly G. Holland Mar 2021

Ccsfs/Ksc Total Lightning Warning Radii Optimization For Merlin Using Preexisting Lightning Areas, Kimberly G. Holland

Theses and Dissertations

The purpose of this research is to optimize lightning warning radii specifications for the 45th Space Wing (45 SW), thus reducing the number of unnecessary warnings that delay ground processing needed for space launch execution at Kennedy Space Center and Cape Canaveral Space Force Station. This thesis sought to answer two key research questions addressing: 1) What radius reduction effectively balances both safety and operations and do reduction recommendations from previous research align with results from the new detection system? 2) What insights can be gained from comparing measurement results for seasonal lightning events as well as lightning types? This …

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Improving Air Battle Management Target Assignment Processes Via Approximate Dynamic Programming, Joseph M. Liles Iv Mar 2021

Improving Air Battle Management Target Assignment Processes Via Approximate Dynamic Programming, Joseph M. Liles Iv

Theses and Dissertations

Military air battle managers face many challenges when directing operations in quickly evolving combat scenarios. These scenarios require rapid decisions to engage moving and unpredictable targets. In defensive operations, the success of a sequence of air battle management decisions is reflected by the friendly force's ability to maintain air superiority by defending friendly assets. We develop a Markov decision process (MDP) model of the air battle management (ABM)problem, wherein a set of unmanned combat aerial vehicles (UCAV) is tasked to defend a central asset from cruise missiles that arrive stochastically over time.

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Examining Crucial Demographic Trends In General Aviation, Joshua D. Meyer Mar 2021

Examining Crucial Demographic Trends In General Aviation, Joshua D. Meyer

Theses and Dissertations

America's General Aviation sector has witnessed significant demographic shifts since the turn of the century. The number of certified, private pilots, non-fatal aircraft accidents, fatal aircraft accidents, and number of general aviation hours flown are all in decline. Meanwhile, the average age of an American private pilot has increased by several years. All of these factors indicate that the industry is in decline. This study determined via mathematical, linear regression that times relationship to the number of annual, fatal General Aviation accidents and the number of certified private pilots is negative. It also proved that the average age of the …

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Bayesian Augmentation Of Cnn-Lstm For Video Classification With Uncertainty Measures, Emmie K. Swize Mar 2021

Bayesian Augmentation Of Cnn-Lstm For Video Classification With Uncertainty Measures, Emmie K. Swize

Theses and Dissertations

The success of Department of Defense (DoD) missions rely heavily on intelligence, surveillance, and reconnaissance (ISR) capabilities, which supply information about the activities and resources of an enemy or adversary. To secure this information, satellites and unmanned aircraft systems collect video data to be classified by either humans or machine learning networks. Traditional automated video classification methods lack measures of uncertainty, meaning the network is unable to identify those cases in which it predictions are made with significant uncertainty. This leads to misclassification, as the traditional network classifies each observation with same amount of certainty, no matter what the observation …

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Model Based Systems Engineering Demonstrator For Air Worthiness With Performance Data Of Department Of Defense Rotorcraft, Bretton M. Bethel Mar 2021

Model Based Systems Engineering Demonstrator For Air Worthiness With Performance Data Of Department Of Defense Rotorcraft, Bretton M. Bethel

Theses and Dissertations

Airworthiness is a process of certifying that an aircraft can be safety operated within specified bounds. This process is essential to ensuring the safety of the aircraft, its personnel, and the surrounding assets. A Model-Based Systems Engineering (MBSE) approach can be utilized as a method to improve the airworthiness process. MBSE is the methodology of creating and utilizing domain models as a means of exchanging and presenting information for a wide variety of disciplines to understand and replacing previous document-based exchange. The objective of this research is to develop a reference architecture with a MBSE approach to perform the airworthiness …

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A Fuzzy Framework For The Air Force Mission Dependency Index, Devin M. Depalmer Mar 2021

A Fuzzy Framework For The Air Force Mission Dependency Index, Devin M. Depalmer

Theses and Dissertations

AFIMSC completed an MDI modernization to support better risk-based decision-making by utilizing tactical mission-owner knowledge to quantify the relationship between facilities and the missions they enable. The resulting facility-mission risk scores leave room for improvement for better use of their intended purposes due to (1) the vulnerability of cognitive biases affecting survey responses due to the use of a traditional risk matrix (2) the lack of resolution between scores from risk ties and (3) the failure to include information from the operational and strategic organizational hierarchy level. This research addresses these concerns through the novel implementation of a fuzzy logic …

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Application Of Game Theory Based Design To U.S. Space Systems, Benjamin C. Donohoo Mar 2021

Application Of Game Theory Based Design To U.S. Space Systems, Benjamin C. Donohoo

Theses and Dissertations

Modern defense systems are designed to static sets of requirements and specifications. This process has worked well in the past but fails to account for the strategic interdependence of design choices made prior to operating systems. However, as the world becomes increasingly competitive, and as the space domain becomes increasingly congested and contested, such interdependence of design can be described using Game Theory. Game Theory is the mathematical study of strategy, actions and payoffs between rational, self-interested actors. Limited extant research has applied Game Theory to system design but focused on a single system being designed cooperatively within a single …

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Utilizing Model Based Systems Engineering To Identify Safety Critical Functions In Airworthiness Certification, Jeffrey C. King Mar 2021

Utilizing Model Based Systems Engineering To Identify Safety Critical Functions In Airworthiness Certification, Jeffrey C. King

Theses and Dissertations

Modern aircraft are complex systems with numerous interacting hardware and software components. To minimize any safety mishaps during operations, new aircraft designs and modifications must go through an airworthiness certification. The current United States Air Force (USAF) airworthiness certification process, captured in MIL-HDBK-516C, is time-consuming and manpower intensive due to extensive documentation. To minimize inefficiencies of this document-based approach, this thesis examined model-based systems engineering (MBSE) to support Safety Critical Function (SCF) thread analysis against criteria found in Section 15 of MIL-HDBK-516C. Within this scope, the research identified an SCF domain-specific profile and style guide using the Systems Modeling Language …

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Data- Driven Asset Degradation Modeling: An Enterprise-Wide Roof System Case Study, Kurt R. Lamm Mar 2021

Data- Driven Asset Degradation Modeling: An Enterprise-Wide Roof System Case Study, Kurt R. Lamm

Theses and Dissertations

Organizations with large facility and infrastructure portfolios have used asset management databases for over ten years to collect and standardize asset condition data. Decision makers use this data to predict asset degradation and expected service life, enabling prioritized maintenance, repair, and renovation actions that reduce asset life-cycle costs and achieve organizational objectives. However, these asset condition forecasts are calculated using standardized, self-correcting distribution models that rely on continuous functions. This research presents four step wise asset condition forecast models that utilize historical asset inspection data to improve prediction accuracy: (1) Slope, (2) Weighted Slope, (3) Condition-intelligent Weighted Slope, and (4) …

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