Keerthi Heragu

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A recently proposed method obtains path delay fault coverages by estimating the count of the number of tested faults instead of actually enumerating them. The estimate become pessimistic when several paths share a set of lines. In this communication, we present a continuum of improved approximations for the counting method, approaching exact fault(More)
We propose a segment delay fault model to represent any general delay defect ranging from a spot defect to a distributed defect. The segment length, L, is a parameter that can be chosen based on available statistics about the types of manufacturing defects. Once L is chosen, the fault list contains all segments of length L and paths whose entire lengths are(More)
We propose a novel algorithm to rapidly identify untestable delay faults using pre-computed static logic implications. Our fault-independent analysis identifies large sets of untestable faults, if any, without enumerating them. The cardinalities of these sets are obtained by using a counting algorithm that has quadratic complexity in the number of lines.(More)
|We develop new statistical techniques for delay fault analysis. True value simulation is performed using a multi-value logic system describing signal states of two consecutive vectors. Signal statistics are used to estimate transition probabilities and observabilities. These allow us to estimate detection probabilities and the coverage for transition(More)
We propose a new statistical technique for estimating fault coverage in combinational circuits. Our method requires fault-free simulation of a random sample of vectors from the test vector set. Fault coverage is computed from controllabilities and observabilities both deened as probabilities and the method is applicable to any fault model like(More)
Lucent TechnologiesWe propose an efficient combinational circuit simulation technique for the recently proposed segment delay fault model. After simulation of a vector pair, activated segments are traced using a depth-first search. A segment numbering scheme finds the number of faults to be simulated. A labeling technique generates edge labels to compute a(More)
A recently published method computes path delay fault coverage from the count of the number of path faults newly sensitized by a simulated vector pair. Such an estimate is pessimistic since several paths may share a set of lines. In this paper, we present a continuum of approximate methods, approaching exact fault simulation, for a tradeoo between accuracy(More)