Abstract: By evaluating critical nodes of opportunistic networks, it was found the nodes that have the greatest influence on the throughput of network, which can support for network optimization and maintenance. The topological condensation graph was constructed according to the characteristics of frequent topology changes in opportunistic networks, and three evaluation metrics, such as second-order degree, connection strength, and key domain importance, were defined. The Euclidean distance of the metrics was employed to characterize the importance of the nodes. Experiments show that the proposed model is effective and superior compared with the betweenness method, and the model has higher accuracy when the time window is set for 20 minutes.

Key words: opportunistic networks, critical nodes, Euclidean distance, topological condensation graph