4 ) an algorithm for reliability upper bound assessment of large - size network is presented , which is based on the principle of topological classification of node - set ; and the lower bound can be also obtained by dual graph of oriented network . 应用图论的点集拓扑分类原理,提出一个计算大型复杂网络可靠度上界的类分法,并应用对偶理论求解网络可靠度的下界。