Hierarchical risk assessment in gas pipelines based on fuzzy aggregation

In this paper, a general framework is given for quantitative risk assessment in large scale systems. As a case study, the leakage risk in natural gas pipeline has been taken into consideration. This system, similar to every other large scale system, involves two major problems of “uncertainty” and “complexity”. To eliminate the latter one, “hierarchical structure” has been adopted and the “uncertainty problem” was tackled by means of “fuzzy set theory”. The simulation results indicate that the proposed fuzzy reasoning and subsequent aggregation provide a good estimation of the large scale pipeline risk grade.