A Test Selection Procedure for Improving the Accuracy of Defect Diagnosis

Procedures that were described earlier increase the accuracy of defect diagnosis by ignoring small subsets of tests in order to produce smaller candidate fault sets. The premise behind these procedures is that most of the tests in a given test set are useful for defect diagnosis, and only small numbers of tests need to be ignored. This paper makes the new observation that it is possible to use small subsets of tests to obtain more accurate diagnosis results. This paper describes a procedure that starts from an empty test set, and adds tests one at a time. The test selected at every iteration is the one that results in the smallest candidate fault set. The addition of tests increases the number of candidate faults gradually. Experimental results for benchmark circuits demonstrate that the addition of tests provides more candidate fault sets with higher degrees of accuracy than the removal of tests. One of these candidate fault sets can be used for failure analysis.