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Optimal Time and Random Inspection Policies for Computer Systems |
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PP: 413-417 |
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Author(s) |
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Xufeng Zhao,
Mingchih Chen,
Toshio Nakagawa,
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Abstract |
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| Faults in computer systems sometimes occur intermittently. This paper applies a standard inspection policy with imperfect
inspection to a computer system: The system is checked at periodic times and its failure is detected at the next checking time with a
certain probability. The expected cost until failure detection is obtained, and when the failure time is exponential, an optimal inspection
time to minimize it is derived. Next, when the system executes computer processes, it is checked at random processing times and its
failure is detected at the next checking time with a certain probability. The expected cost until failure detection is obtained, and when
random processing times are exponential, an optimal inspection time to minimize it is derived. This paper compares optimal times for
two inspection policies and shows that if the random inspection cost is the half of the periodic one, then two expected costs are almost
the same. Finally, we consider the random inspection policy in which the system is checked at the Nth interval of random times and
derive an optimal number N which minimizes the total expected cost. |
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