Comments on "Diagnostic-strategy selection for a series system" by J.A. Nachlas et al

The authors comment on the work of J.A. Nachlas et al. (see ibid., vol.39, no.3, p.273-80, 1990) that presents diagnostic strategies for series systems with both perfect and imperfect testing. Their comment concerns the results given for the perfect-test case. They hold that the proof of the theorem which provides a simple optimal test sequence is incomplete and give a necessary criterion for an optimal strategy.<
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