Dealing with Disappearance of an Actor Set in Social Networks

Social networks are dynamic structures that contain a set of entities and links. In such a dynamic environment, a specific node or a group of nodes can play an important role in the information flow transmission within the network and therefore, its disappearance may lead to a disconnected network or a breakdown in the information flow. The objective of this paper is to extend our previous work on managing a node disappearance to handling the disappearance of a group of nodes. The proposed approach relies on the role played by a group of nodes to conduct network changes and maintain the network connected while restoring the information flow with a similar quality as before the group disappearance. We consider two situations (only one versus many communities) and categorize groups of nodes into three classes (scattered, contiguous and hybrid). Hence, we manage a group disappearance with respect to its class and the network topology by adding new links in a parsimonious way and finding a substitute for a leaving group. Our approach differs from existing link prediction solutions by the fact that it uses the information flow quality as a key performance indicator to identify the potential links to add and/or the possible substitute to a disappearing group. We implement a prototype by using an open source social network analysis library (NetworkX) and we validate our solution through experiments. The results show the benefits of our solution in terms of response time and the number of added links.