Engineering Commons^™

Metrics Of Critical Pair Identification, Zixu Zhang

Open Access Theses

Critical Pair Identification works as a potential assistive tool for human air traffic controllers by identifying potentially dangerous situations that are not detected by proposed automated separation assurance systems. This concept specifically considers conflicts that might arise if aircraft unexpectedly deviate from their planned flight path in the near future. Five metrics of the critical pair concept, Critical Pair Count, Time to Risk Exposure, Lead Time, Risk Exposure Duration and Blunder Sensitivity Index, have been developed and mathematically defined to characterize the safety level of an aircraft pair or a volume of air space. Algorithm that computes proposed metrics is …

Taming Tail Latency For Erasure-Coded, Distributed Storage Systems, Jingxian Fan

Open Access Theses

Nowadays, in distributed storage systems, long tails of responsible time are of particular concern. Modern large companies like Bing, Facebook and Amazon Web Service show that 99.9th percentile response times being orders of magnitude worse than the mean. With the advantages of maintaining high data reliability and ensur- ing enough space eciency, erasure code has become a popular storage method in distributed storage systems. However, due to the lack of mathematical models for analyzing erasure-coded based distributed storage systems, taming tail latency is still an open problem.

In this research, we quantify tail latency in such systems by deriving a …

Service-Level Based Response By Assignment And Order Processing For Warehouse Automation, Zijian He

Open Access Theses

Along with tremendous growth of online sales in this Internet era, unprecedented intensive competition in shortening the delivery time of orders has been occurring among several major online retailers. On the other hand, the idea of customer-oriented service creates a trend of diversified pricing strategy. Different price options are offered to cater to diversified needs of customers. It has become an urgent need for online sales industries to provide the differentiated service levels for different classes of customers with different priorities based on the charging prices and resource constraints of the supply network.

In response to the challenges mentioned above, …

The Casualty Transportation Of Ebola Outbreak In Liberia: A Simulation Study, Hyejin Cho

Open Access Theses

In this paper, we have solved the unique problem of casualty transportation problem under Ebola by developing dynamic policies for vehicle routing in order to provide practical decision support. The objective of the proposed model is to minimize the total transmission risk. We describe the problem with real- constraints and parameters based on the empirical data of the 2014 Ebola outbreak in Liberia. The casualty transportation problem is a variant of Dynamic Pick-up and Delivery Problems (DPDP), in which a vehicle is dispatched to demand location in real time and it then transports the demands to the aimed area (destination). …

Developing Agent-Based Simulation Models Of Task Performance Of Cognitively Diverse Teams, Megan Marie Nyre

Open Access Theses

Team-oriented work dominates industry, government, and academic areas with the goal of solving increasingly complex problems. However, the scope and external validity of traditional human factors research is inherently limited by the time and resources required to conduct laboratory studies. The model described in this thesis integrates simulation with human factors by providing an operationalized model that incorporates cognitive diversity and domain expertise. Convergence and functionality of the model have been established through a series of analyses, and a clear path for future research has been identified. By integrating simulation methods into human factors subject areas, researchers may be able …

Enhancing A Flight Dispatcher Display For Safer Flight Operations, Jeongjoon Boo

Open Access Theses

This study assesses capability of flight dispatchers to adopt enhancements on their display that enables detection of flights in abnormal activities and investigation of the causes. Three approaches were used. First, the expected function for enhancements was designed by collecting information from different places about what technologies are available for consideration. Second, hierarchical task analysis was conducted based on data collected by interviewing a former flight dispatcher in order to assess operational capability to handle the enhancement. Third, based on the results of first two approaches, a display prototype that includes the enhancement was developed and evaluated for usability and …

Designing A Sustainable And Transferable Inventory Management System For Small Healthcare Facilities, Shree Frazier

Open Access Theses

Managing the costs of supplies within healthcare facilities has been a task that has plagued the health industry for many years. Many facilities are accustomed to using a par system approach. This involves bringing an inventory item to an amount sufficient for daily operation. This method often requires daily inspection by a healthcare worker, which reduces his/her time spent performing value added tasks. Employees at small healthcare facilities have multiple responsibilities, therefore they cannot afford to spend much time on inventory management. A proposed approach is the Kanban method, which allows for strict monitoring of inventory items without the need …

Application Of Bayesian Networks In Consumer Service Industry, Yuan Gao

Open Access Theses

Gao, Yuan. M.S.I.E., Purdue University. December 2014. Application of Bayesian Networks in Consumer Service Industry. Major professor: Vincent G. Duffy The purpose of the present study is to explore the application of Bayesian networks in the consumer service industry to model causal relationships within complex risk factor structures using aggregate data. An analysis of the Hawaii tourism market was conducted to find out how visitor characteristics affect their behavior and experience as consumers during the trips, and influence the tourism market outcomes represented by measurable factors. Two hypotheses were proposed regarding the use of aggregate data and the influence of …

Designing Sustainable Mentoring Programs: Examining The Role Of Social Community In The Stem College Student Experience, Joi-Lynn Mondisa

Open Access Theses

In order to begin to understand how to design programs that promote community development and produce beneficial outcomes for community members, we must first define the elements and functions of such a community. In this thesis, I define social community as an environment where like-minded individuals engage indynamic, multidirectional interactions that facilitate social support . Using a human-integrated systems approach, I propose a social community model for STEM minority mentoring programs to understand how a community's design plays a role in the learning and enrichment of its members. The social community model is comprised of three main components: program …

Dissolution Rate And Mechanism Of Metals In Molten Aluminum Alloy A380, Hengyu Zhu

Open Access Theses

Shot sleeve is a very easily worn out part in a high-pressure die-casting machine due to serious dissolution of the area underneath the pouring hole. It is because during a normal pouring process, the high temperature molten aluminum will impact and dissolve that area of the shot sleeve by complex chemical and physical process. Rotation experiment was carried out to H13 and four kinds of refractory metal samples. SEM and EDS pictures were taken in order to investigate the microstructure and the dissolution mechanism of these materials. This suggests a high strength niobium is an ideal material for that area …

Evaluating Intensity As A Controller Function For Nextgen Scenarios With Increased Capacity, Caitlin Anne Surakitbanharn

Open Access Theses

Automated separation assurance is the most mature concept to handle increasing airspace traffic and capacity needs, yet the system lacks a way to pre-emptively identify aircraft separation problems. The intensity control measure looks to find situations where if an aircraft pair makes an unplanned change in heading or altitude at the wrong moment, an unrecoverable situation arises. This research analyzes static, open loop air traffic data in an en-route sector to determine how many high intensity aircraft pairs (HIP) exist per minute, and if the intensity measure is a safely manageable function for air traffic controllers. It is found that …

The Multi-Depot Minimum Latency Problem With Inter-Depot Routes, Timothy W. Duket

Open Access Theses

The Minimum Latency Problem (MLP) is a class of routing problems that seeks to minimize the wait times (latencies) of a set of customers in a system. Similar to its counterparts in the Traveling Salesman Problem (TSP) and Vehicle Routing Problem (VRP), the MLP is NP-hard. Unlike these other problem classes, however, the MLP is customer-oriented and thus has impactful potential for better serving customers in settings where they are the highest priority. While the VRP is very widely researched and applied to many industry settings to reduce travel times and costs for service-providers, the MLP is a more recent …

Exploratory Study In Container Loading Embraer 190 Aircraft, Ryan H. Auyeung

Open Access Theses

Since the dawn of aviation, cargo loading on aircraft has remained virtually constant. A person and a baggage cart together have been the primary method of loading baggage on to aircraft, and this practice has virtually remained unchanged, especially for narrow body aircraft. This study explores the question of whether a loading device, designed for Embraer 190 aircraft, can increase economic efficiency by reducing aircraft turnaround times, increasing aircraft utilization and reducing work hours. In the course of designing a theoretical loading device for an Embraer 190, various literature ranging from elaborate articulating conveyor belts, to the use of LD3-45W …

Detecting Air Traffic Controller Interventions In Recorded Air Transportation System Data, Yul Kwon

Open Access Theses

In this study, I propose a systematic method of detecting aircraft deviation due to air traffic controller (ATC) intervention. The aircraft deviations associated with ATC interventions are detected using a heuristic algorithm developed from analyzing the actual positions of an aircraft to its filed flight plan when the aircraft trajectories were identified as having an encounter in a loss-of-separation incident. An actual (closed-loop) flight trajectory of the Cleveland Air Route Traffic Control Center (ZOB ARTCC) was collected from the FlightAware database. This was compared with the corresponding planned (open-loop) trajectory dataset generated by the Microsoft© Flight Simulator X (FSX). I …

Modeling And Optimization Of Care Transitions, Yuming Mo

Open Access Theses

More than 145 million people live with at least one chronic condition, and almost half of them have multiple conditions. As a result, many managed care and integrated delivery systems have taken a great interest in alleviating the many deficiencies in managing the current care system that spans across various care delivery settings. In addition, many Americans have to rely on some social health insurance plan to cover her care expenses. As a result, these patients often may not been sufficiently cured but have to be transitioned to less expensive but less medically intensive facilities, due to the increasing pressure …

A Comparative Analysis Of An Original And A Post-Hoc Application Of Lean Six Sigma Methodology, Jin Qiu

Open Access Theses

Current society develops faster and faster every day with customers' demands increasing rapidly. Decreasing time for product development and enhancing customer satisfaction are becoming more significant. In the business world, there is no industry that could exist without an efficient supply chain. In the fierce competitive environment of today, the supply chain must address potential problems and risks that may exist and assure continuous improvement.

One common supply chain management practice in many industries is to apply lean methodology to the supply chain model in order to maximize the customers' value and eliminate waste. By eliminating waste, the process can …

A Lean Logistics Assessment Tool For Smes In The Manufacturing Sector, Diana Lorena Sanchez Ramirez

Open Access Theses

This study developed an assessment tool to rate the maturity of the current and desired states of lean logistics operations in small and medium enterprises. The tool consists of 48 best practices classified into 8 critical factors: Inventory, Transportation, Administration, Information Systems, Warehouse, Forecasting, Packaging and Supplier Network. Each of the best practices and critical factors were identified throughout a thorough literature review and comparative analysis between authors to define commonalities among them. Using gap analysis; this tool results in a SWOT matrix providing a roadmap for lean implementation. The resulting model was evaluated by subject matter experts in different …

The Effect Of Job Performance Aids On Quality Assurance, Erik David Fosshage

Open Access Theses

Job performance aids (JPAs) have been studied for many decades in a variety of disciplines and for many different types of tasks, yet this is the first known research experiment using JPAs in a quality assurance (QA) context. The objective of this thesis was to assess whether a JPA has an effect on the performance of a QA observer performing the concurrent dual verification technique for a basic assembly task. The JPA used in this study was a simple checklist, and the design borrows heavily from prior research on task analysis and other human factors principles. The assembly task and …

Nanohub Database Analysis: Using Anomaly Detection Method And Principal Component Analysis, Mengyang Qi

Open Access Theses

This thesis analyzes usage data from nanoHUB.org, which is a web-based infrastructure for e-collaboration among nanotechnology simulation community. Previous analysis of nanoHUB database showed he nanoHUB usage data follows an unknown, heavy-tailed distributions. This thesis extends the analysis and develops an automatic anomaly detection method based on piece-wise linear approximation. The anomaly here refers to collective user behaviors different from others. The result shows that the method can accurately detect the anomalies in the unknown, heavily detailed distribution. This thesis also applies anomaly detection method and principal component analysis to other databases in nanoHUB and successfully reveals differences between different …

Modeling Preventive Maintenance In Complex Systems, Jessica Rivas

Open Access Theses

This thesis presents an explicit consideration of the impacts of modeling decisions on the resulting maintenance planning. Incomplete data is common in maintenance planning, but is rarely considered explicitly. Robust optimization aims to minimize the impact of uncertainty--here, in contrast, I show how its impact can be explicitly quantified. Doing so allows decision makers to determine whether it is worthwhile to invest in reducing uncertainty about the system or the effect of maintenance. The thesis consists of two parts. Part I uses a case study to show how incomplete data arises and how the data can be used to derive …

High Speed Turning Of Compacted Graphite Iron (Cgi) Using Controlled Modulation, Tyler Paul Stalbaum

Open Access Theses

Compacted graphite iron (CGI) is a material which emerged as a candidate material to replace cast iron (CI) in the automotive industry for engine block castings. Its thermal and mechanical properties allow the CGI-based engines to operate at higher cylinder pressures and temperatures than CI-based engines, allowing for lower fuel emissions and increased fuel economy. However, these same properties together with the thermomechanical wear mode in the CGI-CBN system result in poor machinability and inhibit CGI from seeing wide spread use in the automotive industry.

In industry, machining of CGI is done only at low speeds, less than V = …

Scheduling In Mohs Micrographic Surgery Clinics, Stephen Vincent Steidle

Open Access Theses

Mohs Micrographic Surgery (MMS) is a surgical method used for the excision of aggressive skin cancers in areas of high cosmetic importance, such as the face and hands. The practice has been gaining popularity worldwide for its low recurrence rates and cosmetic results. Current clinics though are plagued by extreme wait times and an overall poor patient experience. In this paper we look to explore this problem by applying systems engineering principles including optimization and scheduling with the goal of improving the patient experience. Currently, little literature exists exploring the difficulties associated with scheduling for MMS clinic which primarily revolve …