Abstract (EN)

Central nodes (i.e. , prominent actors) in a social network are those that are linked to other nodes in an extensive or critical manner. Therefore, their removal may lead to points of failure. The objective of the present work is to exploit network topology to devise an approach towards (i) nding substitute(s) to a deleted node, and (ii) adding appropriate links to avoid a fragmentation of the network into unconnected subgraphs. The approach exploits the role played by nodes to predict the new structure of a social network once one entity disappears. The role of a node in the network is expressed in terms of the number of interactions it has with the rest of the network. Three important roles are considered: the leader , the mediator and the witness . An entity acts as a leader, a mediator or a witness if it has a high degree centrality, betweenness centrality and closeness centrality, respectively.