Dependability assessment using binary decision diagrams (BDDs)

Presents the DREDD (Dependability and Risk Evaluation using Decision Diagrams) algorithm which incorporates coverage modeling into a BDD solution of a combinatorial model. BDDs, which do not use cutsets to generate system unreliability, can be used to find exact solutions for extremely large systems. The DREDD algorithm takes advantage of the efficiency of the BDD solution approach and increases the accuracy of a combinatorial model by including consideration of imperfect coverage. The usefulness of combinatorial models, long appreciated for their logical structure and concise representational form, is extended to include many fault-tolerant systems previously thought to require more complicated analysis techniques in order to include coverage modeling. In. This paper, the DREDD approach is presented and applied to the analysis of two sample systems, the F18 flight control system and a fault-tolerant multistage interconnection network.<>