Operations Research, Systems Engineering and Industrial Engineering Commons^™

A Two-Stage Approach To Ridesharing Assignment And Auction In A Crowdsourcing Collaborative Transportation Platform., Peiyu Luo

Electronic Theses and Dissertations

Collaborative transportation platforms have emerged as an innovative way for firms and individuals to meet their transportation needs through using services from external profit-seeking drivers. A number of collaborative transportation platforms (such as Uber, Lyft, and MyDHL) arise to facilitate such delivery requests in recent years. A particular collaborative transportation platform usually provides a two sided marketplace with one set of members (service seekers or passengers) posting tasks, and the another set of members (service providers or drivers) accepting on these tasks and providing services. As the collaborative transportation platform attracts more service seekers and providers, the number of open …

Solving School Bus Routing And Student Assignment Problems With Heuristic And Column Generation Approach., Di Zhang

Electronic Theses and Dissertations

In this dissertation, we solve a school bus routing problem of transporting students including special education (handicapped) students and assigning them in Oldham county education district. The main contribution of this research is that we consider special education students (Type-2) along with other students (Type-1) and design a comprehensive school bus schedule to transport both kinds of students at the same time. Also, a student assignment mathematical model is presented to optimize the number of bus stops in use as well as one important measure of service quality, the total student walking distance. Comparing to the classic clustering methods, heuristic …

Binder Jetting Additive Manufacturing Process Fundamentals And The Resultant Influences On Part Quality., Hadi Miyanaji

Electronic Theses and Dissertations

Binder jetting additive manufacturing (BJ-AM) technology is a process by which a part is fabricated layer by layer through depositing liquid binder in the designated regions of each layer until the feature is complete. Due to the use of binder in geometry generation, this process possesses various advantages over the other additive manufacturing technologies including the ability to create colored objects via colored binders, lower cost, lack of heat-induced defects, and its potential capability to print a variety of materials such as metals, sands and ceramics. Although the application of the binder jetting process has been recently reported by different …

Tooling For Injection Molding Using Laser-Powder Bed Fusion., Mohith Ram Buxani

Electronic Theses and Dissertations

Laser-Powder Bed Fusion (L-PBF) has been considered for some time by the injection molding industry for the fabrication of tooling for injection molding in order to address large lead times and costs for tool-making. Computer-aided simulations are also routinely used to evaluate new part and mold designs as well as understanding the effects of material compositions and processing conditions on part quality and overall productivity. However, there remains a significant need to integrate the perspectives from injection molding, 3D printing, metal powders, and component design and process simulation to better utilize LPBF for fabricating tooling required for injection molding. The …

Ultrasonic Nondestructive Evaluation Of Metal Additive Manufacturing., Venkata Karthik Nadimpalli

Electronic Theses and Dissertations

Metal Additive Manufacturing (AM) is increasingly being used to make functional components. One of the barriers for AM components to become mainstream is the difficulty to certify them. AM components can have widely different properties based on process parameters. Improving an AM processes requires an understanding of process-structure-property correlations, which can be gathered in-situ and post-process through nondestructive and destructive methods. In this study, two metal AM processes were studied, the first is Ultrasonic Additive Manufacturing (UAM) and the second is Laser Powder Bed Fusion (L-PBF). The typical problems with UAM components are inter-layer and inter-track defects. To improve the …

Simulation-Based Analysis And Optimization Of The United States Army Performance Appraisal System., Lee A. Evans

Electronic Theses and Dissertations

In this dissertation, a discrete event simulation framework is considered to replicate the dynamics, structure, and regulatory constraints placed on the officers in the U.S. Army. Using performance appraisal data provided by the United States Army Human Resources Command, we create a multi-objective response function that quantifies the human behavior associated with evaluating subordinates. Utilizing simulation-optimization techniques for model validation enables estimating unknown input parameters, such as human behavior, based on historical data. Furthermore, the model allows users to analyze the effects of current constraints on the evaluation system and the effects of proposed personnel policy changes.The effectiveness of the …

Multi Self-Adapting Particle Swarm Optimization Algorithm (Msapso)., Gerhard Koch

Electronic Theses and Dissertations

The performance and stability of the Particle Swarm Optimization algorithm depends on parameters that are typically tuned manually or adapted based on knowledge from empirical parameter studies. Such parameter selection is ineffectual when faced with a broad range of problem types, which often hinders the adoption of PSO to real world problems. This dissertation develops a dynamic self-optimization approach for the respective parameters (inertia weight, social and cognition). The effects of self-adaption for the optimal balance between superior performance (convergence) and the robustness (divergence) of the algorithm with regard to both simple and complex benchmark functions is investigated. This work …

Ambulatory Clinic Exam Room Design With Respect To Computing Devices: A Laboratory Simulation Study, Dustin T. Weiler, Tyler Satterly, Shakaib U. Rehman, Maury A. Nussbaum, Neale R. Chumbler, Gary M. Fischer, Jason J. Saleem

Faculty and Staff Scholarship

Background—Challenges persist regarding how to integrate computing effectively into the exam room, while maintaining patient-centered care. Purpose—Our objective was to evaluate a new exam room design with respect to the computing layout, which included a wall-mounted monitor for ease of (re)-positioning. Methods—In a lab-based experiment, 28 providers used prototypes of the new and older “legacy” outpatient exam room layouts in a within-subject comparison using simulated patient encounters. We measured efficiency, errors, workload, patient-centeredness (proportion of time the provider was focused on the patient), amount of screen sharing with the patient, workflow integration, and provider situation awareness. Results—There were no statistically …

Performance, Workload, And Usability In A Multiscreen, Multi-Device, Information-Rich Environment, Jason J. Saleem, Dustin T. Weiler

Faculty and Staff Scholarship

Potential benefits of multiscreen and multiple device environments were assessed using three different computing environments. A single factor, within-subject study was conducted with 18 engineering students in a laboratory experiment. Three levels for the computing environment factor included one with a desktop computer with a single monitor (control, condition A); one with a desktop with dual monitors, as well as a single tablet computer (condition B); and one with a desktop with a single monitor, as well as two tablet computers (condition C). There was no statistically significant difference in efficiency or workload when completing scenarios for the three computing …

Artificial Olfactory System For Multi-Component Analysis Of Gas Mixtures., Alexander Aleksandrovich Larin

Electronic Theses and Dissertations

Gas analysis is an important part of our world and gas sensing technology is becoming more essential for various aspects of our life. A novel approach for gas mixture analysis by using portable gas chromatography in combination with an array of highly integrated and selective metal oxide (MOX) sensors has been studied. We developed a system with small size (7 x 13 x 16 inches), low power consumption (~10 W) and absence of special carrier gases designed for portable field analysis (assuming apriori calibration). Low ppb and even sub-ppb level of detection for some VOCs was achieved during the analysis …

Performance Analysis Of Organizations As Complex Systems., William C. Harrington Jr.

Electronic Theses and Dissertations

This dissertation provides a method for evaluating the difference in performance after an organization makes a change while considering the stochastic nature in which it operates. A procedure that uses simulation to estimate outcomes by adjusting controllable parameters and leaving uncontrolled parameters unadjusted is proposed. As healthcare organizations are considered as highly complex systems, a case study involving a scheduling tactic change in the mother-baby service line of a hospital is used to demonstrate application of this procedure. The goal in the case study was to reduce delays in transitioning care of mother patients from the labor and delivery unit …

A Multi-Period Facility Location Model For Service Organizations Operating In A Competitive Environment., Sven W. Brose

Electronic Theses and Dissertations

This thesis develops a multi-period, mathematical programming location model for facilities operating in a competitive environment. The objective is to maximize the profit in a variable demand environment. The solution of the problem can either be done in a robust or in a dynamic manner. A robust solution methodology forecasts the demand for all the periods in the planning horizon and provides a robust solution that may be suboptimal for any given period, but optimal when all the periods are taken into consideration. A problem with this approach is that it requires accurate forecast of demand for multiple periods into …

The Effect Of Role Assignment And Personality Subtypes In Simulation On Critical Thinking Development, Situation Awareness, And Perceived Self-Efficacy Of Nursing Baccalaureate Students., Dustin Travis Weiler

Electronic Theses and Dissertations

Previous studies have evaluated the effectiveness of high fidelity patient simulators (HFPS) on nursing training. However, a gap exists on the effects of role assignment and student personality subtypes in simulation scenarios. This thesis explored the effects of role assignment and personality on critical thinking, situation awareness, and self-efficacy in baccalaureate-level nursing students. Using researcher-developed tools and altering previously validated tools to fit the simulation scenario, the effects of role assignment and personality were determined. Role assignment and personality were found to have a significant effect on critical thinking and self-efficacy, but not situation awareness. It was determined that roles …

Investigation Of Influential Factors On Selecting An Engineering Major., Paige A. Miller

Electronic Theses and Dissertations

This thesis evaluates the factors that freshman engineering students at the University of Louisville are taking into consideration when deciding on their major within engineering. The outcome of the research is expected to help to shape the syllabus of the ENGR 110 course, which is a mandatory class for all freshman engineering students. ENGR 110 is comprised of course lectures, department presentations, and company presentations. Currently, both the department and company presentations are held outside of course times. The influential factors identified by this research may help shape the course so that these factors are discussed thoroughly about each major …

Dynamic Warehouse Optimization Using Predictive Analytics., Parvaneh Jahani

Electronic Theses and Dissertations

The forward area is a small area of a warehouse with a low picking cost. Two approaches that are investigated for selecting the SKUs of this area and the allocated space are the static and the dynamic approaches. In the case that decisions about the forward area are made periodically (e.g. yearly) and the products' demand patterns are completely ignored, the FRP is static. We developed two heuristics that solve the large discrete assignment, allocation, and sizing problem simultaneously. Replenishing the same product in the same place of the forward area brings about a ``Locked" layout of the fast picking …

Order Picking Strategies For Healthcare Warehouses., Ehsan Khodabandeh

Electronic Theses and Dissertations

Order picking is the process of collecting goods and items in specified quantities from storage locations, in response to customer orders. Since many labor resources are involved in this process, finding ways to make it more efficient have been a primary goal for researchers and practitioners. Determining a better allocation of products to the storage areas, finding the best route and sequence to pick multiple products, and choosing the best picking policies to minimize congestion in the aisles are just a few of many objectives regarding order picking process. Due to regulatory compliances and the chance of product spoilage, additional …

Optimization Models And Algorithms For Demand Response In Smart Grid., Guangyang Xu

Electronic Theses and Dissertations

For demand response in smart grid, a utility company wants to minimize total electricity cost and end users want to maximize their own utility. The latter is considered to consist of two parts in this research: electricity cost and convenience/comfort. We first develop a system optimal (SO) model and a user equilibrium (UE) model for the utility company and end users, respectively and compare the difference of the two. We consider users' possible preference on convenience over cost-saving under the real-time pricing in smart grid, and each user is assumed to have a preferred time window for using a particular …

Simulation Modeling For Energy Consumption Of Residential Consumers In Response To Demand Side Management., Prajwal Khadgi

Electronic Theses and Dissertations

Energy efficiency in the electricity distribution system continues to gain importance as demand for electricity keeps rising and resources keep diminishing. Achieving higher energy efficiency by implementing control strategies and demand response (DR) programs has always been a topic of interest in the electric utility industry. The advent of smart grids with enhanced data communication capabilities propels DR to be an essential part of the next generation power distribution system. Fundamentally, DR has the ability to charge a customer the true price of electricity at the time of use, and the general perception is that consumers would shift their load …

Production And Inventory Control In Complex Production Systems Using Approximate Dynamic Programming., Han Wu

Electronic Theses and Dissertations

Production systems focus not only on providing enough product to supply the market, but also on delivering the right product at the right price, while lowering the cost during the production process. The dynamics and uncertainties of modern production systems and the requirements of fast response often make its design and operation very complex. Thus, analytical models, such as those involving the use of dynamic programming, may fail to generate an optimal control policy for modern production systems. Modern production systems are often in possession of the features that allow them to produce various types of product through multiple working …

Green Logistic Network Design : Intermodal Transportation Planning And Vehicle Routing Problems., Xiaoren Duan

Electronic Theses and Dissertations

Due to earth's climate change and global warming, environmental consideration in the design of logistic systems is accelerating in recent years. In this research we aim to design an efficient and environmentally friendly logistical system to satisfy both government and carriers. In particular, we considered three problems in this dissertation: intermodal network design, deterministic green vehicle routing problem and stochastic green vehicle routing problem. The first problem aims to design an economic and efficient intermodal network including three transportation modes: railway, highway and inland waterway. The intent of this problem is to increase the utilization percentage of waterway system in …

A Comparative Usability Study Of Web-Based Personal Health Records., Alexandra Doggett

Electronic Theses and Dissertations

Previous research on Personal Health Records (PHRs) has focused on applications that are “tethered” to a specific Electronic Health Record (EHR). However, this is a gap in research on the usability of unaffiliated, independent PHRs, as well as a gap in research on college-aged PHR users. Based on this gap in the literature, a single factor, within-subject experiment was conducted using 18 participants from the University of Louisville to determine if one PHR had superior usability and design. The testing included the completion of six tasks in three different PHRs. Dependent variables included task time, mouse movement, mouse clicks, keystrokes, …

The Electropolishing Of Electron Beam Melting, Additively Manufactured Ti6al4v Titanium : Relevance, Process Parameters And Surface Finish., Austin Lassell

Electronic Theses and Dissertations

Additive Manufacturing (AM) is the next frontier in manufacturing technology, but with this new frontier comes new challenges in post processing techniques. In an attempt to gain further knowledge of the post processing of metal AM components, the Electropolishing (EP) of Electron Beam Melting (EBM), Additively Manufactured Ti- 6Al-4V alloy parts is investigated in the following work. Additive Manufacturing (AM) is predominant in a number of industries, with electronics and consumer goods, aerospace, automotive and medical constituting the majority of AM sales. For most of these, Powder Bed Fusion (PBF) AM technology is of great interest given the ability of …

Mental Workload Measurement For Competitive Video Games., Jamal Mcfarland

Electronic Theses and Dissertations

The purpose of this study was to explore different ways to measure mental workload for competitive video games using two different techniques: heart rate variability (HRV) and the NASA Task Load Index (TLX). eSports is a rising form of a competitive sport as well as a source of entertainment for people all over the world. I write this in hopes to find efficient and verified ways to estimate mental workload. I also hope this work can pioneer the expansion of literature for the competitive gaming scene.

The study design is a single factor, within-subject design. The single factor was Game …

Operational Decision Making For Medical Clinics Through The Use Of Simulation And Multi-Attribute Utility Theory., Bo Sun

Electronic Theses and Dissertations

Currently, health care is a large industry that concerns everyone. Outpatient health care is an important part of the American health care system and is one of the strongest growth areas in the health care system. Many people pay attention to how to keep basic health care available to as many people as possible. A large health care system is usually evaluated by many performance measures. For example, the managers of a medical clinic are concerned about increasing staff utilization; both managers and patients are concerned about patient waiting time. In this dissertation, we study decision making for clinics in …

Spare Parts On Demand Using Additive Manufacturing : A Simulation Model For Cost Evaluation., Stefan Jedeck

Electronic Theses and Dissertations

Little is known about the impact of additive manufacturing in the spare part supply chain. A few studies are available, but they focus on specific parts and their applications only. A general model, which can be adapted to different applications, is nonexistent. This dissertation proposes a decision making framework that enables an interested practitioner/manager to decide whether using additive manufacturing to make spare parts on demand is economical when compared to conventional warehousing strategy. The framework consists of two major components: a general discrete event simulation model and a process of designing a wide range of simulation scenarios. The goal …

Optimization Of Support Structures For Selective Laser Melting., Kai Zeng

Electronic Theses and Dissertations

Additive Manufacturing (AM) users rely on experiments and experience to predict the performance of AM processes. This trial and error approach for qualifying AM parts takes significant time and money. Simulation tools are an urgent need for today’s AM industry. One area of need is the automatic generation of optimized support structures based upon the scan patterns used to produce those structures. This research seeks to develop support structure generation tools based on real scan pattern and thermo-mechanical simulation tools for Selective Laser Melting (SLM) developed at the University of Louisville and being commercialized by 3DSIM, LLC. In order to …

Simulation-Based Optimization Of Mitigation Strategies For Pandemic Influenza., Arsalan Paleshi

Electronic Theses and Dissertations

Millions of people have been infected and died as results of influenza pandemics in human history. In order to prepare for these disasters, it is important to know how the disease spreads. Further, intervention strategies should be implemented during the pandemics to mitigate their ill effects. Knowledge of how these interventions will affect the pandemic course is paramount for decision makers. This study develops a simulation-based optimization model which aims at finding a combination of strategies that result in the best value for an objective function of defined metrics under a set of constraints. Also, a procedure is presented to …

Supply Chain Flexibility In The Special Purpose Vehicle Industry., Florian J. Loderbauer 1982-

Electronic Theses and Dissertations

Supply chains of the Special Purpose Vehicle (SPV) industry are complex and with many constraints. Since the SPV industry is a special field of operation, there is no classical supply chain strategy which is appropriate. It is possible to apply concepts of industries with similar requirements but there is a high loss of time and money because these classical concepts do not fit to the SPV industry. Even strategies of the conventional automobile industry cannot be transferred. Therefore, there is the need to develop a supply chain concept for companies of the SPV industry. As a first step, basic knowledge …

A Mathematical Programming Approach For Dispatching And Relocating Ems Vehicles., Farshad Majzoubi 1983-

Electronic Theses and Dissertations

We consider the problem of dispatching and relocating EMS vehicles during a pandemic outbreak. In such a situation, the demand for EMS vehicles increases and in order to better utilize their capacity, the idea of serving more than one patient by an ambulance is introduced. Vehicles transporting high priority patients cannot serve any other patient, but those transporting low priority patients are allowed to be rerouted to serve a second patient. We have considered three separate problems in this research. In the first problem, an integrated model is developed for dispatching and relocating EMS vehicles, where dispatchers determine hospitals for …

After Sales Supply Chain Risk Management., Steffen Luksch

Electronic Theses and Dissertations

Lean supply chains with cost optimized production and logistics processes in the automotive industry have become a benchmark for other industries. Short delivery times, low inventories and high availability are parameters which assume a robust supply chain. In industrial practice we see, however, that in the After Sales business particularly related to the supply of automotive spare parts, that there are always unforeseen delays in delivery. In order to avoid service level losses on the focal firm level due to missing parts it is necessary to understand the risk structure on the supplier side. For this reason, a risk model …