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Articles 1 - 11 of 11

Full-Text Articles in Engineering

The Effects Of Weather Recognition Training On General Aviation Pilot Situation Assessment And Tactical Decision Making When Confronted With Adverse Weather Conditions, Chansik Kim Aug 2011

The Effects Of Weather Recognition Training On General Aviation Pilot Situation Assessment And Tactical Decision Making When Confronted With Adverse Weather Conditions, Chansik Kim

All Dissertations

Previous general aviation (GA) accident studies showed that decision errors were more associated with fatal GA accidents than other kinds of human errors, and weather related accidents, especially continued visual flight rules (VFR) flight into instrument meteorological conditions (IMC), remained the major cause of fatal GA accidents. Thus, finding the underlying causes of GA pilots' decision errors and continued VFR flight into adverse weather conditions are needed to reduce weather related GA accidents as well as fatal GA accidents.
Causal factors and hypotheses of weather related GA accidents show that knowledge, experience, motivation, and weather information frequently have been referred …


Metaheuristics For Hub Location Models, Ornurai Sangsawang Aug 2011

Metaheuristics For Hub Location Models, Ornurai Sangsawang

All Dissertations

In this research, we propose metaheuristics for solving two p-hub median problems.. The first p-hub median problem, which is NP-hard, is the uncapacitated single p-hub median problem (USApHMP). In this problem, metaheuristics such as genetic algorithms, simulated annealing and tabu search, are applied in different types of representations. Caching is also
applied to speed up computational time of the algorithms. The results clearly demonstrate that tabu search with a permutation solution representation, augmented with caching is the highest performing method, both in terms of solution quality and computational time among these algorithms for the USApHMP. We also investigate the performance …


Anticipating U.S. Population-Level Health And Economic Impacts Using Discrete-Event Simulation To Guide Health Policy Decisions, Odette Reifsnider Aug 2011

Anticipating U.S. Population-Level Health And Economic Impacts Using Discrete-Event Simulation To Guide Health Policy Decisions, Odette Reifsnider

All Dissertations

This dissertation presents two applications of discrete-event simulation (DES) to represent clinical processes: (1) a model to quantify the risk of the maternal obese and diabetic intrauterine environment influence on progression to adult obesity and diabetes, and (2) a model to evaluate health and economic outcomes of different smoking cessation strategies. The first application considers the public health impact of the diabetic and obese intrauterine environment's effect on the prevalence of diabetes and obesity across subsequent generations. We first develop a preliminary DES model to investigate and characterize the epidemiology of diabetes during pregnancy and birth outcomes related to maternal …


Improving Quality Of Service In Ems Systems By Reducing Disparities Between Service Zones, Sunarin Chanta Aug 2011

Improving Quality Of Service In Ems Systems By Reducing Disparities Between Service Zones, Sunarin Chanta

All Dissertations

Emergency medical service (EMS) systems respond to emergency or urgent calls so as to provide immediate care, such as pre-hospital care and/or transportation, to hospitals. Care must be provided in a timely manner; in fact quality of service is usually directly associated with response time. To reduce the response time, the number and location of vehicles within the service area are important variables. However with limited capacity, increasing the number of vehicles is often an infeasible alternative. Therefore, a critical design goal is to decide at which facilities stations should be located in order to serve as much demand as …


Micro Feature Enhanced Sinter Bonding Of Metal Injection Molded (Mim) Parts To A Solid Substrate, Thomas Martens May 2011

Micro Feature Enhanced Sinter Bonding Of Metal Injection Molded (Mim) Parts To A Solid Substrate, Thomas Martens

All Dissertations

In metal injection molding (MIM), fine metal powders are mixed with a binder and injected into molds, similar to plastic injection molding. After molding, the binder is removed from the part, and the compact is sintered to almost full density.
The obstacle to sinter bonding a MIM part to a conventional (solid) substrate lies in the sinter shrinkage of the MIM part, which can be up to 20%, meaning that the MIM part shrinks during sintering, while the conventional substrate maintains its dimensions. This behavior would typically inhibit bonding and/or cause cracking and deformation of the MIM part. It is …


Tight Polyhedral Representations Of Discrete Sets Using Projections, Simplices, And Base-2 Expansions, Stephen Henry May 2011

Tight Polyhedral Representations Of Discrete Sets Using Projections, Simplices, And Base-2 Expansions, Stephen Henry

All Dissertations

This research effort focuses on the acquisition of polyhedral outer-approximations to the convex hull of feasible solutions for mixed-integer linear and mixed-integer nonlinear programs. The goal is to produce desirable formulations that have superior size and/or relaxation strength. These two qualities often have great influence on the success of underlying solution strategies, and so it is with these qualities in mind that the work of this dissertation presents three distinct contributions.
The first studies a family of relatively unknown polytopes that enable the linearization of polynomial expressions involving two discrete variables. Projections of higher-dimensional convex hulls are employed to reduce …


A Decision Support System For Assessing Conveyance Options And Modeling Passenger Flow In Airport Terminals, Ping-Nan Chiang May 2011

A Decision Support System For Assessing Conveyance Options And Modeling Passenger Flow In Airport Terminals, Ping-Nan Chiang

All Dissertations

This dissertation focuses on the use of passenger conveyance systems and modeling passenger flow in airport terminals. The successfully designed airport concourse must perform at a level that meets the needs of its users - the passengers. In this research, we propose a database design methodology that allows key conveyance statistics to be analyzed within specific locations across the airport terminal. Using passenger conveyance observations collected at five North American airports, the database enables airport planners, operators and consultants to assess passenger behavior and conveyance device performance. Results from this section of the research were in direct support of the …


Pilot Weather Decision Making And The Influence Of Passenger Pressure, Jaclyn Baron May 2011

Pilot Weather Decision Making And The Influence Of Passenger Pressure, Jaclyn Baron

All Dissertations

The purpose of this study is to determine the effect of social pressure on general aviation (GA) pilots' weather decision making. Data have shown that GA accidents associated with visual flight rules (VFR) flight into instrument meteorological conditions (IMC) are more likely to result in fatalities than other types of GA accidents. This problem is compounded by the addition of passengers, who have been found to be present onboard during VFR into IMC accidents more frequently than in other types of GA accidents. The question is whether passengers influence a pilot's decision to continue flight into adverse weather. The extent …


Modeling And Optimization Of Stochastic Process Parameters In Complex Engineering Systems, Paul Goethals May 2011

Modeling And Optimization Of Stochastic Process Parameters In Complex Engineering Systems, Paul Goethals

All Dissertations

For quality engineering researchers and practitioners, a wide number of statistical tools and techniques are available for use in the manufacturing industry. The objective or goal in applying these tools has always been to improve or optimize a product or process in terms of efficiency, production cost, or product quality. While tremendous progress has been made in the design of quality optimization models, there remains a significant gap between existing research and the needs of the industrial community. Contemporary manufacturing processes are inherently more complex - they may involve multiple stages of production or require the assessment of multiple quality …


In-Wheel Coupled Suspenison And Drive System For Attitude Control And Vehicle Propulsion, Robert Clippard May 2011

In-Wheel Coupled Suspenison And Drive System For Attitude Control And Vehicle Propulsion, Robert Clippard

All Dissertations

The automotive marketplace is a volatile and dynamic system driven by consumer desires, marketing, fuel prices, technology, and legislation. Recently many of these factors have culminated in a common effort to encourage hybrid and electric vehicle development. The technology for electric vehicles has finally found enough maturity to be implemented into consumer based vehicles from hybrid SUVs to high performance sports cars. This expansion in available propulsion systems and vehicle architectures has spurred research and development into new and novel approaches for propulsion as well as systems to provide increased ride comfort.
This work presents a dual electric motor drive …


Impact Of High-Speed Inkjet On Digital Printing And Traditional Offset Lithography, Caroline Sellars May 2011

Impact Of High-Speed Inkjet On Digital Printing And Traditional Offset Lithography, Caroline Sellars

All Theses

This thesis was prepared in order to examine the impact of high-speed inkjet printing on the offset lithography market within the commercial printing and publishing segments. Digital printing has become more widespread in recent years, but high-speed inkjet is making advances in its capabilities and technologies. With the printing industry evolving and print consumers preferring shorter print runs and in a shorter amount of time, print technologies are evolving to meet these needs. Print-on-demand is growing tremendously in the publishing industry, and personalization and 1-to-1 marketing is growing in the commercial printing segment as well. Market demand is changing in …