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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Predicting and quantifying seated comfort and discomfort using objective and subjective measures

Openshaw, Scott David 01 May 2011 (has links)
Comfort is a sensation and state of being that many people seek when they are working in the office, driving in a car, flying on an airplane, or laying in a hospital bed. The literature identifies many definitions and interpretations for comfort and discomfort, and many different ways that researchers have tried to measure comfort and discomfort. de Looze proposed a model to explain the relationship between comfort and discomfort using three key components: (a) the human, (b) the product, and (c) the environment. This dissertation added a measurement component to the model. In a repeated measures design, subjects (n=35) sat in three different office chairs for 60 minutes each on two different dates. Researchers collected subjective survey data and objective electronic data related to perceived sitting comfort and discomfort while participants completed office computer tasks. Data were analyzed to predict and quantify office worker seated comfort and discomfort using linear modeling and neural network modeling. Correlation values from the linear regression model developed in this experiment were R2 < 0.70, while the single hidden-layer neural network model predicted the comfort/discomfort responses with a higher correlation (R2=0.997). The 35 subjects in the study perceived measurable comfort differences between the three chairs tested. Subjective questions that treated comfort and discomfort in a non-linear relationship discriminated chair differences better than questions using a linear relationship. There was no significant difference between male and female comfort/discomfort responses. Comfort ratings decreased over time, while discomfort increased over time; at least 45-minute comfort testing is needed to understand subjects' comfort/discomfort in a particular office chair. Five common factors that were important to the model included: (a) fit of the product to the person, (b) the features of the product itself, (c) the time spent with the product, (d) the subjective questions, and (e) the objective pressure measurements.
2

Pressure Mapping and Efficiency Analysis of an EPPLER 857 Hydrokinetic Turbine

Clark, Tristan 30 October 2017 (has links)
No description available.

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