Diagnosing double regular systems

We consider the problem of testing sequentially the components of a multi-c omponent system, when the testing of each component is costly. We propose a new testing policy, that can be executed in polynomial time in the input s ize, and show that it is cost-minimal in the average case sense, for certai n double regular systems that include regular (in particular, threshold) sy stems with identical components. This result generalizes known results for series, parallel, and, more generally, for k-out-of-n systems.