Effect of DOA spares on predicted system reliability (switching system)

The authors examine the effect of the initially defective probability, or as it is also known, the dead-on-arrival (DOA) probability, of spare circuit packs on the predicted reliability of a duplex system. A reliability model to incorporate the DOA probability and the associated spare-pack replacement time is developed. Calculations are made in an attempt to quantify the effect of these two variables on the predicted downtime of a representative duplex system. For the system used in this study, it is shown that if the DOA probability is 5% or more, the predicted downtime estimate is 70% greater than the estimate obtained using the standard assumption of a DOA probability of zero.<
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