[R] System Reliability Metrics
Jon Stearley
jrstear at sandia.gov
Wed Dec 21 19:02:34 CET 2005
I need to calculate some metrics such as Mean Time Between Failure
(MTBF), etc (see http://www.cs.sandia.gov/~jrstear/ras for a more
complete list). I have observations like
start end state
1 2005-11-11 09:05:00 2005-11-11 12:20:00 Scheduled Downtime
2 2005-11-12 13:42:00 2005-11-12 14:45:00 Unscheduled Downtime
where each row describes the system state between start and end
times. Time between observations indicates a Production state. The
metrics of interest involve simple ratios of total time spent in
various states, number of transitions, etc. I'd like to plot period
MTBF values (eg monthly vertical bars), as well as a cumulative MTBF
(eg a line whose last value indicates MTBF for the entire time
range), etc.
What is the best approach in R towards these results?
Irregular time series seem a natural fit for the observations, and
the reporting periods for the metrics will have regular periods - so
I've perused the stats, tseries, and its packages. A markov class
could be used (eg msm package), but that's probably overkill (like
the reliability packages concord and irr)? My goal is to calculate
the metrics in the simplest and most natural way. Can someone please
advise me on a best approach?
Thank you!
--
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| Jon Stearley (505) 845-7571 (FAX 844-9297) |
| Sandia National Laboratories Scalable Systems Integration |
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