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Activity Number:
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30
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Type:
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Contributed
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Date/Time:
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Sunday, July 29, 2007 : 2:00 PM to 3:50 PM
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Sponsor:
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Section on Quality and Productivity
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| Abstract - #309218 |
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Title:
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Monitoring the Slopes of Linear Profiles
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Author(s):
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Junjia Zhu*+
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Companies:
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The Pennsylvania State University
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Address:
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331A Thomas Building, University Park, PA, 16802,
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Keywords:
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Profile Monitoring ; Simple Linear Regression ; Statistical Process Control
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Abstract:
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In this paper, we focus on monitoring the slopes of linear profiles. A Shewhart-type control chart for monitoring slopes of linear profiles is proposed. Both Phase I and Phase II applications are discussed. The performance of the proposed chart in Phase I applications is demonstrated using both real-life data in an illustrative example and simulated data in a probability of signal study. For Phase II applications, the average run length (ARL) is used for comparison. It is shown that the ARL of the proposed control chart depends only on the shifts of slopes; whereas the ARL of the multivariate T2 chart depends on both the shifts of slopes and the correlation between the estimated slope and the intercept. When such a correlation is low (say within +/-0.6), the proposed control chart has a better ARL performance than the T2 chart.
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