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Doctoral Dissertations

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Articles 1 - 30 of 132

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

Quantifying Restoration Costs In The Aftermath Of An Extreme Event Using System Dynamics And Dynamic Mathematical Modeling Approaches, Akhilesh Ojha Jan 2019

Quantifying Restoration Costs In The Aftermath Of An Extreme Event Using System Dynamics And Dynamic Mathematical Modeling Approaches, Akhilesh Ojha

Doctoral Dissertations

"Extreme events such as earthquakes, hurricanes, and the like, lead to devastating effects that may render multiple supply chain critical infrastructure elements inoperable. The economic losses caused by extreme events continue well after the emergency response phase has ended and are a key factor in determining the best path for post-disaster restoration. It is essential to develop efficient restoration and disaster management strategies to ameliorate the losses from such events. This dissertation extends the existing knowledge base on disaster management and restoration through the creation of models and tools that identify the relationship between production losses and restoration costs. The ...


The Tabu Ant Colony Optimizer And Its Application In An Energy Market, David Donald Haynes Jan 2019

The Tabu Ant Colony Optimizer And Its Application In An Energy Market, David Donald Haynes

Doctoral Dissertations

"A new ant colony optimizer, the 'tabu ant colony optimizer' (TabuACO) is introduced, tested, and applied to a contemporary problem. The TabuACO uses both attractive and repulsive pheromones to speed convergence to a solution. The dual pheromone TabuACO is benchmarked against several other solvers using the traveling salesman problem (TSP), the quadratic assignment problem (QAP), and the Steiner tree problem. In tree-shaped puzzles, the dual pheromone TabuACO was able to demonstrate a significant improvement in performance over a conventional ACO. As the amount of connectedness in the network increased, the dual pheromone TabuACO offered less improvement in performance over the ...


Power System Planning In Disparate Systems: Modeling Sustainability And Electricity Access, Destenie Nock Jan 2019

Power System Planning In Disparate Systems: Modeling Sustainability And Electricity Access, Destenie Nock

Doctoral Dissertations

Electricity goals around the world tend to focus on increasing social benefit through one of two avenues: (1) increasing overall system sustainability or (2) increasing access to electricity. These goals guide the transition of the power system. In pursuit of these goals decision makers will need modeling tools that can inform decisions, in a way that is flexible enough to include a wide range of preferences and goals. It is clear that the future generation mix of the power system will change, but the most sustainable solution, will change based on a country's goals. This dissertation will explore the ...


Freeform Extrusion Fabrication Of Advanced Ceramics And Ceramic-Based Composites, Wenbin Li Jan 2019

Freeform Extrusion Fabrication Of Advanced Ceramics And Ceramic-Based Composites, Wenbin Li

Doctoral Dissertations

"Ceramic On-Demand Extrusion (CODE) is a recently developed freeform extrusion fabrication process for producing dense ceramic components from single and multiple constituents. In this process, aqueous paste of ceramic particles with a very low binder content ( < 1 vol%) is extruded through a moving nozzle to print each layer sequentially. Once one layer is printed, it is surrounded by oil to prevent undesirable water evaporation from the perimeters of the part. The oil level is regulated just below the topmost layer of the part being fabricated. Infrared radiation is then applied to uniformly and partially dry the top layer so that the yield stress of the paste increases to avoid part deformation. By repeating the above steps, the part is printed in a layer-wise fashion, followed by post-processing. Paste extrusion precision of different extrusion mechanisms was compared and analyzed, with an auger extruder determined to be the most suitable paste extruder for the CODE system. A novel fabrication system was developed based on a motion gantry, auger extruders, and peripheral devices. Sample specimens were then produced from 3 mol% yttria stabilized zirconia using this fabrication system, and their properties, including density, flexural strength, Young's modulus, Weibull modulus, fracture toughness, and hardness were measured. The results indicated that superior mechanical properties were achieved by the CODE process among all the additive manufacturing processes. Further development was made on the CODE process to fabricate ceramic components that have external/internal features such as overhangs by using fugitive support material. Finally, ceramic composites with functionally graded materials (FGMs) were fabricated by the CODE process using a dynamic mixing device"--Abstract, page iv.


A Methodology To Predict Community College Stem Student Retention And Completion, Jennifer Lynn Snyder Jan 2018

A Methodology To Predict Community College Stem Student Retention And Completion, Jennifer Lynn Snyder

Doctoral Dissertations

"Numerous government reports point to the multifaceted issues facing the country's capacity to increase the number of STEM majors, while also diversifying the workforce. Community colleges are uniquely positioned as integral partners in the higher education ecosystem. These institutions serve as an access point to opportunity for many students, especially underrepresented minorities and women. Community colleges should serve as a major pathway to students pursuing STEM degrees; however student retention and completion rates are dismally low. Therefore, there is a need to predict STEM student success and provide interventions when factors indicate potential failure. This enables educational institutions to ...


Analyzing Factors Affecting Patient Satisfaction Using The Kano Model, Tejaswi Materla Jan 2018

Analyzing Factors Affecting Patient Satisfaction Using The Kano Model, Tejaswi Materla

Doctoral Dissertations

"Customer needs associated with the healthcare sector are constantly evolving with the technological advancements, rising costs, and shifts in patient demographics. Challenges associated with understanding patient needs impact the quality of care and life, safety, and satisfaction. The objective of this research was to develop a methodology to collect and analyze the needs associated with healthcare units that differ based on the type of care and services and patient perceptions over time. The proposed methodology provides insights into the voice of the customer through visualization of the relationship between the performance of quality attributes and customer satisfaction. Cronbach's alpha ...


Data Driven Decision Making Tools For Transportation Work Zone Planning, Samareh Moradpour Jan 2018

Data Driven Decision Making Tools For Transportation Work Zone Planning, Samareh Moradpour

Doctoral Dissertations

"This research provides tools and methods for integrating stakeholder input and crash data analytics to better guide transportation engineers in effective work zone design and management. Three key contributions are presented: the importance of stakeholder input in traffic management strategies, application of data mining and pattern recognition to identify high-risk drivers in work zones, and the use of multinomial logistic regression (MLR) as a tool to understand key findings from historic crash data. Work zone signage is mandated by the Manual on Uniform Traffic Control Devices (MUTCD), but the current configurations are often criticized by the driving public and state ...


A Model For Sustaining New Technology Based On Government Incentives, Girish Upreti Aug 2017

A Model For Sustaining New Technology Based On Government Incentives, Girish Upreti

Doctoral Dissertations

The diffusion of new technology that provides environmental benefits may require government incentives for a duration of time, especially when the technology is expensive. The Center of Systems Research and Education (CASRE) model is developed that analyzes the impact of incentives in sustaining new technologies to allow their social acceptance. The CASRE model includes both demand and supply variables associated with incentive policy to sustain new technology. The key to market dissemination and sustainability is the Investment Tax Credit (ITC) levels provided by the government. The level of ITC is based on the current cost to the customer and the ...


Sustainability Analysis For New Technologies Of Biofuels And Additive Manufacturing, Nelson A. Granda Marulanda Aug 2017

Sustainability Analysis For New Technologies Of Biofuels And Additive Manufacturing, Nelson A. Granda Marulanda

Doctoral Dissertations

This work is a compendium of different sustainability analysis on new technologies. The first chapter performed a Life Cycle Analysis of a biofuel process where pine woodchips are used to create SynGas. The study was done using a 10 tons gasifier, the mass balance of the reaction and an input/output analysis. All the data obtained was input into a freeware LCA software and the results were compared to the use of regular produced natural gas. The second chapter creates a benchmark of energy intensity and presents a case using binder jetting technology. Different Additive Manufacturing technologies energy intensity was ...


Flight Risk Management And Crew Reserve Optimization, Ying Zhang Aug 2017

Flight Risk Management And Crew Reserve Optimization, Ying Zhang

Doctoral Dissertations

There are two key concerns in the development process of aviation. One is safety, and the other is cost. An airline running with high safety and low cost must be the most competitive one in the market. This work investigates two research efforts respectively relevant to these two concerns.

When building support of a real time Flight Risk Assessment and Mitigation System (FRAMS), a sequential multi-stage approach is developed. The whole risk management process is considered in order to improve the safety of each flight by integrating AHP and FTA technique to describe the framework of all levels of risks ...


Model For Prioritization Of High Variation Elements In Discrete Production Systems, Bharadwaj Venkatesan Aug 2017

Model For Prioritization Of High Variation Elements In Discrete Production Systems, Bharadwaj Venkatesan

Doctoral Dissertations

The complexity of the modern manufacturing enterprise has led companies to look for techniques and methodologies for improving production performance. Lean manufacturing techniques have been applied in the US with varying degrees of success, and Theory of Constraints (TOC) has been used to emphasize the flow of production and identify performance improvement projects. One aspect of manufacturing for which there has been limited academic or industrial research till date is the impact of variation on production performance and the identification of improvement projects based on variation. This thesis develops a methodology to incorporate random and simultaneous occurrence of variability in ...


An Optimization Framework For Integrating Variable Capacity And Pavement Thickness Requirements In Highway Cost Allocation, Saurav Kumar Dubey Aug 2017

An Optimization Framework For Integrating Variable Capacity And Pavement Thickness Requirements In Highway Cost Allocation, Saurav Kumar Dubey

Doctoral Dissertations

The objective of Highway Cost Allocation (HCA) is to distribute or allocate in a fair and rational manner the cost of a transportation facility (either a highway or bridge) among all vehicle classes using it. The purpose of this dissertation is to study and enhance a model, known as the least-core model, to include both pavement thickness and traffic capacity requirements for all coalitions formed with a given group of vehicle classes. Considering vehicle classes as players and groups of vehicle classes as coalitions, it is possible to quantify the thickness and width of pavement needed to accommodate the vehicle ...


Electricity And Fuel Consumption In A Lean Energy Supply Chain, Mostafa Ghafoorivarzaneh May 2017

Electricity And Fuel Consumption In A Lean Energy Supply Chain, Mostafa Ghafoorivarzaneh

Doctoral Dissertations

Human activities are the main sources of environmental pollution. Awareness about this fact, motivated us to make changes in different paradigms of our lives including industrial or personal activities. Environmental activities assumed to have conflict with financial objectives, in this study we try to align business requirements with environmental concerns.

Among all human activities, generating energy has the most negative impact on the environment. The major part of the generated energy will be consumed in transportation and industrial demand which makes them the most effective targets for the reduction of greenhouse gas emission. In a lean environment, small batch sizes ...


Transition To Electric Vehicles In The California Automobile Industry, Jinglu Song May 2017

Transition To Electric Vehicles In The California Automobile Industry, Jinglu Song

Doctoral Dissertations

This dissertation presents a comprehensive study on the market adoption of electric vehicle and policy impact of the Zero Emission Vehicle (ZEV) mandate in the California automotive market. This research is primarily consisting of three parts. The author first built a technology innovation pricing model based on multi-nomial logit modelling method. This studies the dynamics among customer preferences, market acceptance and policy impact on vehicle pricing in the California automotive market. Results show that the ZEV mandate could profoundly enhance the market adoption of electric vehicles. There is a threshold on the magnitude of policy intervention. If the number of ...


Exploring A Semi-Virtual Reality System Impacting Learning Curves Of College Students, Hongbiao Yang May 2017

Exploring A Semi-Virtual Reality System Impacting Learning Curves Of College Students, Hongbiao Yang

Doctoral Dissertations

Virtual reality (VR) is a trending technology used in a broad range of fields including education and has become one of the most promising directions for educators. In this research, the investigation focuses on how the semi-immersive VR application can be used for educational purposes by exploring the VR factors and the interactions between these factors. A theoretical learning framework is also proposed to offer an explanation for the beneficial effects of education brought by VR at a high level.

This research consists of three parts. First, this research will introduce the development of Walk-in-Place Learning System (WIPLS), a semi-immersive ...


Programming Problems On Time Scales: Theory And Computation, Rasheed Basheer Al-Salih Jan 2017

Programming Problems On Time Scales: Theory And Computation, Rasheed Basheer Al-Salih

Doctoral Dissertations

"In this dissertation, novel formulations for several classes of programming problems are derived and proved using the time scales technique. The new formulations unify the discrete and continuous programming models and extend them to other cases "in between." Moreover, the new formulations yield the exact optimal solution for the programming problems on arbitrary isolated time scales, which solve an important open problem. Throughout this dissertation, six distinct classes of programming problems are presented as follows. First, the primal as well as the dual time scales linear programming models on arbitrary time scales are formulated. Second, separated linear programming primal and ...


Theory And Practice Of Supply Chain Synchronization, Michael Prokle Jan 2017

Theory And Practice Of Supply Chain Synchronization, Michael Prokle

Doctoral Dissertations

In this dissertation, we develop strategies to synchronize component procurement in assemble-to-order (ATO) production and overhaul operations. We focus on the high-tech and mass customization industries which are not only considered to be very important to create or keep U.S. manufacturing jobs, but also suffer most from component inventory burden.

In the second chapter, we address the deterministic joint replenishment inventory problem with batch size constraints (JRPB). We characterize system regeneration points, derive a closed-form expression of the average product inventory, and formulate the problem of finding the optimal joint reorder interval to minimize inventory and ordering costs per ...


Methods For Incorporating Ecological Impacts With Climate Uncertainty To Support Robust Flood Management Decision-Making, Caitlin M. Spence Jan 2017

Methods For Incorporating Ecological Impacts With Climate Uncertainty To Support Robust Flood Management Decision-Making, Caitlin M. Spence

Doctoral Dissertations

Modern and historic flood risk management involves accommodating multiple sources of sources of uncertainty and potential impacts across a broad range of interrelated sectors. Sources of uncertainty that affect planning include internal climate variability, anthropogenic changes such as land use and system performance expectations, and more recently changes in climatology that affect the resources supporting the system. Flood management systems potentially impact human settlements within and beyond the systems’ scope of planning, local weather patterns, and associated ecological systems. Federal guidelines across nations have called for greater consideration of uncertainty and impacts of water resources planning projects, but methods for ...


Multi-Criteria Decision Making When Planning Sustainable Multimodal Transportation Routes In A Linear Corridor, Marie Louis Jan 2017

Multi-Criteria Decision Making When Planning Sustainable Multimodal Transportation Routes In A Linear Corridor, Marie Louis

Doctoral Dissertations

In urban and suburban locations, public transit can be seen as an effective mode

of daily transportation. The majority of the time, travelers would seek the cheapest, shortest, and possibly most eco-friendly means of transit. When designing public transit network systems, transportation planners and decision-makers, with input from stakeholders, should strive to optimize transportation services to meet the needs of the population most efficiently and at the lowest cost, that is, providing a transportation system that s the three E's of the sustainability concept: environment, social equity, and economic.

Previous studies have focused on sustainability as the primary concern ...


Decision Analytical Methods For Robust Water Infrastructure Planning Under Deep Uncertainty, Mehmet Umit Taner Jan 2017

Decision Analytical Methods For Robust Water Infrastructure Planning Under Deep Uncertainty, Mehmet Umit Taner

Doctoral Dissertations

Deep uncertainties resulting from climate change, demographic pressures, and rapidly evolving socioeconomic conditions are challenging the way that water planners design and operate large-scale infrastructure systems. Conventionally, water infrastructures have been developed using stationary methods, assuming that the underlying uncertainties can be derived from historical data or experience. However, these methods are less useful under deeply uncertain climate and socioeconomic conditions, in which the future can be substantially different from the past and cannot be expressed by well-defined probability distributions. The recognition of deep uncertainties in long-term water resources planning has led to the development of “decision-analytical” frameworks that do ...


Cognition-Based Approaches For High-Precision Text Mining, George John Shannon Jan 2017

Cognition-Based Approaches For High-Precision Text Mining, George John Shannon

Doctoral Dissertations

"This research improves the precision of information extraction from free-form text via the use of cognitive-based approaches to natural language processing (NLP). Cognitive-based approaches are an important, and relatively new, area of research in NLP and search, as well as linguistics. Cognitive approaches enable significant improvements in both the breadth and depth of knowledge extracted from text. This research has made contributions in the areas of a cognitive approach to automated concept recognition in.

Cognitive approaches to search, also called concept-based search, have been shown to improve search precision. Given the tremendous amount of electronic text generated in our digital ...


Multi-Objective Combinatorial Optimization Problems In Transportation And Defense Systems, Hadi Farhangi Jan 2017

Multi-Objective Combinatorial Optimization Problems In Transportation And Defense Systems, Hadi Farhangi

Doctoral Dissertations

"Multi-objective Optimization problems arise in many applications; hence, solving them efficiently is important for decision makers. A common procedure to solve such problems is to generate the exact set of Pareto efficient solutions. However, if the problem is combinatorial, generating the exact set of Pareto efficient solutions can be challenging. This dissertation is dedicated to Multi-objective Combinatorial Optimization problems and their applications in system of systems architecting and railroad track inspection scheduling. In particular, multi-objective system of systems architecting problems with system flexibility and performance improvement funds have been investigated. Efficient solution methods are proposed and evaluated for not only ...


Constrained Multi-Group Project Allocation Using Mahalanobis Distance, Abdulaziz Saud Alkabaa Dec 2016

Constrained Multi-Group Project Allocation Using Mahalanobis Distance, Abdulaziz Saud Alkabaa

Doctoral Dissertations

Optimal allocation is one of the most active research areas in operation research using binary integer variables. The allocation of multi constrained projects among several options available along a given planning horizon is an especially significant problem in the general area of item classification. The main goal of this dissertation is to develop an analytical approach for selecting projects that would be most attractive from an economic point of view to be developed or allocated among several options, such as in-house engineers and private contractors (in transportation projects). A relevant limiting resource in addition to the availability of funds is ...


Development Of Instrumentation And Control Systems For An Integral Large Scale Pressurized Water Reactor, Matthew Rowland Morrow Lish Dec 2016

Development Of Instrumentation And Control Systems For An Integral Large Scale Pressurized Water Reactor, Matthew Rowland Morrow Lish

Doctoral Dissertations

Small and large scale integral light water reactors are being developed to supply electrical power and to meet the needs of process heat, primarily for water desalination. This dissertation research focuses on the instrumentation and control of a large integral inherently safe light water reactor (designated as I2S-LWR) which is being designed as part of a grant by the U.S. Department of Energy Integrated Research Project (IRP). This 969 MWe integral pressurized water reactor (PWR) incorporates as many passive safety features as possible while maintaining competitive costs with current light water reactors. In support of this work ...


Integrating The Cost Of Quality Into Multi-Products Multi-Components Supply Chain Network Design, Waleed Abdussalam Gueir Dec 2016

Integrating The Cost Of Quality Into Multi-Products Multi-Components Supply Chain Network Design, Waleed Abdussalam Gueir

Doctoral Dissertations

More than ever before the success of a company heavily depends on its supply chain and how efficient the network. A supply chain needs to be configured in such a manner as to minimize cost while still maintaining a good quality level to satisfy the end user and to be efficient, designing for the network and the whole chain is important. Including the cost of quality into the process of designing the network can be rewording and revealing. In this research the concept of cost of quality as a performance measure was integrated into the supply chain network designing process ...


Forecasting Employee Turnover In Large Organizations, Xiaojuan Zhu Aug 2016

Forecasting Employee Turnover In Large Organizations, Xiaojuan Zhu

Doctoral Dissertations

Researchers and human resource departments have focused on employee turnover for decades. This study developed a methodology forecasting employee turnover at organizational and departmental levels to shorten lead time for hiring employees. Various time series modeling techniques were used to identify optimal models for effective employee-turnover prediction based on a large U.S organization's 11-year monthly turnover data. A dynamic regression model with additive trend, seasonality, interventions, and a very important economic indicator efficiently predicted turnover. Another turnover model predicted both retirement and quitting, including early retirement incentives, demographics, and external economic indicators using the Cox proportional hazard model ...


A Tool Kit For Building Hbcu Technology Transfer Supply Chain Networks Using An Advanced Planning System, Clovia Hamilton Aug 2016

A Tool Kit For Building Hbcu Technology Transfer Supply Chain Networks Using An Advanced Planning System, Clovia Hamilton

Doctoral Dissertations

This mixed methods study describes the development of a university technology transfer that Historically Black Colleges and Universities (HBCUs) can use to become more self-reliant financially. HBCUs lag behind their peer non-HBCUs because historically they have been under-served and were originally established largely as teaching and blue collar trade schools. Increased involvement in research oriented activities such as technology transfer will likely enable HBCUs to grow into new or stronger research institutions. The literature review revealed several problem areas with non-HBCUs university technology transfer include: (1) lack of quality standard benchmarks; (2) resource planning issues; (3) processing delays; and (4 ...


High Reliability Organizational Suggestions To Reduce The Risk Of Hospital-Associated Infections, Sandra Catrice Affare May 2016

High Reliability Organizational Suggestions To Reduce The Risk Of Hospital-Associated Infections, Sandra Catrice Affare

Doctoral Dissertations

Over 1.7 million hospital-associated infections (HAIs), resulting in 99,000 deaths, occur each year in the United States. HAIs are defined as infections that occur within 48 hours of hospital admission without evidence of the infection being present or incubating at the time of admission. HAIs are a major concern to the medical community due to the potential loss of life and high costs. Healthcare providers should be accountable for reducing the rates of HAIs and society needs to hold them accountable for the safe implementation and outcomes of the services they provide.

A high-reliability organization (HRO) is commonly ...


Empirical Analysis To Investigate The Influence Of Cultural Dimensions On Risk-Taking Behavior Among Hispanic And Non-Hispanic Construction Workers In United States, Kaveri Ajit Thakur May 2016

Empirical Analysis To Investigate The Influence Of Cultural Dimensions On Risk-Taking Behavior Among Hispanic And Non-Hispanic Construction Workers In United States, Kaveri Ajit Thakur

Doctoral Dissertations

The focus of this research was to investigate the influence of cultural dimensions on risk-taking behavior among construction workers. Following a comprehensive literature review, a conceptual model was presented to evaluate `Intended Behavior in Risky Situations' in construction work environment. While the differences in risk-taking behaviors is generally acknowledged, the influence of culture is overlooked very easily. A total of 94 responses were collected from construction sites in the Knoxville Tennessee area by means of a questionnaire based on the conceptual model factors. The final sample consisted of 89 responses was evaluated using Partial lease Square - Structural Equation Modeling. The ...


Applications Of Simulation And Optimization Techniques In Optimizing Room And Pillar Mining Systems, Angelina Konadu Anani Jan 2016

Applications Of Simulation And Optimization Techniques In Optimizing Room And Pillar Mining Systems, Angelina Konadu Anani

Doctoral Dissertations

"The goal of this research was to apply simulation and optimization techniques in solving mine design and production sequencing problems in room and pillar mines (R&P). The specific objectives were to: (1) apply Discrete Event Simulation (DES) to determine the optimal width of coal R&P panels under specific mining conditions; (2) investigate if the shuttle car fleet size used to mine a particular panel width is optimal in different segments of the panel; (3) test the hypothesis that binary integer linear programming (BILP) can be used to account for mining risk in R&P long range mine production sequencing; and (4) test the hypothesis that heuristic pre-processing can be used to increase the computational efficiency of branch and cut solutions to the BILP problem of R&P mine sequencing.

A ...