  Social networks contain implicit knowledge that can be used to infer
hierarchical relations that are not explicitly present in the available data.
Interaction patterns are typically affected by users' social relations. We
present an approach to inferring such information that applies a link-analysis
ranking algorithm at different levels of time granularity. In addition, a
voting scheme is employed for obtaining the hierarchical relations. The
approach is evaluated on two datasets: the Enron email data set, where the goal
is to infer manager-subordinate relationships, and the Co-author data set,
where the goal is to infer PhD advisor-advisee relations. The experimental
results indicate that the proposed approach outperforms more traditional
approaches to inferring hierarchical relations from social networks.
