SSBDDs and Double Topology for Multiple Fault Reasoning

The paper presents a novel view on the Structurally Synthesized BDDs (SSBDD) as a model with inherent double topology for compact modeling of single faults and efficient reasoning of multiple faults. The nodes of SSBDDs represent lower level signal path topology in the original circuit, and the paths of SSBDD represent higher level topology of conditions to be processed during fault reasoning. The double topological view on SSBDDs allows to give easy explanation of the limitations of existing methods of multiple fault testing, and shows the ways how to avoid fault masking. A generalization of the test pair approach in a form of the concept of test groups is introduced for testing multiple faults.