To define the semantic relation S, we take into account a temporal context specified by a time window of 26 minutes as reported in (Lucchese et al., 2013).
if two queries belong to the same search session, as defined by a fixed length time window, then each constituent word pair within them is considered to be members of the set S. In real-life settings, even within a session of a specified time length, users often multi-task their activities (possibly by using multiple browser tabs or windows) (Lucchese et al., 2013;Wang et al., 2013;Mehrotra and Yilmaz, 2017).