An Efficient Binary-Decision-Diagram-Based Approach for Network Reliability and Sensitivity Analysis

Reliability and sensitivity analysis is a key component in the design, tuning, and maintenance of network systems. Tremendous research efforts have been expended in this area, but two practical issues, namely, imperfect coverage (IPC) and common-cause failures (CCF), have generally been missed or have not been fully considered in existing methods. In this paper, an efficient approach for fully incorporating both IPC and CCF into network reliability and sensitivity analysis is proposed. The challenges are to allow multiple failure modes introduced by IPC and to cope with multiple dependent faults caused by CCF simultaneously in the analysis. Our methodology for addressing the aforementioned challenges is to separate the consideration of both IPC and CCF from the combinatorics of the solution, which is based on reduced ordered binary decision diagrams (ROBDD). Due to the nature of the ROBDD and the separation of IPC and CCF from the solution combinatorics, our approach has a low computational complexity and is easy to implement. A sample network system is analyzed to illustrate the basics and advantages of our approach. A software tool that we developed for fault-tolerant network reliability and sensitivity analysis is also presented.