Efficient Algorithms for Finding Diversified Top-K Structural Hole Spanners in Social Networks

A structural hole spanner in a social network is a user who bridges multiple communities, and he can benefit from acting the bridging role, such as arbitrating information across different communities or getting earlier access to valuable and diverse information. Existing studies of finding hole spanners either identified redundant hole spanners (i.e., communities bridged by different hole spanners are redundant) or found nonredundant hole spanners only by network structure. Unlike the existing studies, we not only study a problem of finding top- k hole spanners that connect nonredundant communities in the social network, but also consider the tie strengths between different pairs of users and the different information sharing rates of different users, so that after removing the found users, the number of blocked information diffusion is maximized. In addition, we devise a novel ( 1 - 1 e )-approximation algorithm for the problem, where e is the base of the natural logarithm. We further propose a fast randomized algorithm with a smaller time complexity. Our experiment results demonstrate that, after removing the nodes found by the proposed two algorithms, the numbers of blocked information diffusion can be up to 80% larger than those by existing algorithms.