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Activity Number:
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407
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Type:
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Topic Contributed
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Date/Time:
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Wednesday, August 5, 2009 : 8:30 AM to 10:20 AM
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Sponsor:
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Section on Physical and Engineering Sciences
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| Abstract - #305298 |
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Title:
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A Simple Step-Stress Model with an Immune Fraction
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Author(s):
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Nandini Kannan*+ and Debasis Kundu
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Companies:
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The University of Texas at San Antonio and Indian Institute of Technology Kanpur
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Address:
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One UTSA Circle, San Antonio, TX, 78249,
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Keywords:
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step-stress model ; immune fraction
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Abstract:
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In reliability or survival analysis, one is often interested in the effects of different stress levels such as temperature, voltage, and dose on lifetimes of experimental units. Accelerated testing allows the experimenter to increase these stress levels to obtain information about the underlying distribution more quickly than would be possible under normal conditions. A special class of accelerated tests is the class of step-stress tests. In this paper, we develop inference for the simple step-stress model assuming exponential lifetimes that allows for the presence of an immune population. The immune population represents resistant items that are not affected by the stress. We adapt the cumulative exposure model discussed by Nelson and obtain the MLEs of the parameters. The model is fit to some data on altitude decompression sickness.
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