OBDD-based evaluation of reliability and importance measures for multistate systems subject to imperfect fault coverage

• Published in: IEEE transactions on dependable and secure computing Vol. 2; no. 4; pp. 336 - 347
• Main Authors: Yung-Ruei Chang, Amari, S.V., Sy-Yen Kuo
• Format: Journal Article
• Language: English
• Published: Washington IEEE 01.10.2005; IEEE Computer Society
• Subjects: Availability; Boolean; Boolean functions; Data structures; Decision making models; Decomposition; Degradation; Design optimization; Failure; Fault tolerance; Fault tolerant systems; fault-coverage; Fission reactors; importance measure; Index Terms- Reliability; Information systems; Mathematical models; Methods; multistate system; Nuclear power generation; Nuclear power plants; OBDD; Power generation; Power system modeling; Power system reliability; Random variables; Reliability; Statistical analysis; Studies; System theory
• ISSN: 1545-5971; 1941-0018
• DOI: 10.1109/TDSC.2005.51

Algorithms for evaluating the reliability of a complex system such as a multistate fault-tolerant computer system have become more important. They are designed to obtain the complete results quickly and accurately even when there exist a number of dependencies such as shared loads (reconfiguration), degradation, and common-cause failures. This paper presents an efficient method based on ordered binary decision diagram (OBDD) for evaluating the multistate system reliability and the Griffith's importance measures which can be regarded as the importance of a system-component state of a multistate system subject to imperfect fault-coverage with various performance requirements. This method combined with the conditional probability methods can handle the dependencies among the combinatorial performance requirements of system modules and find solutions for multistate imperfect coverage model. The main advantage of the method is that its time complexity is equivalent to that of the methods for perfect coverage model and it is very helpful for the optimal design of a multistate fault-tolerant system.