To identify news stories on the same topic, most TDT approaches rely on traditional vector space models (Salton et al., 1975), as more sophisticated natural language processing techniques have not yet proven to be useful for this task.
significant advances in sentence-level event extraction have been made over the last decade, in particular as the result of standardization efforts such as TimeML (Pustejovsky et al., 2003a) and TimeBank (Pustejovsky et al., 2003b), as well as dedicated evaluation tasks (ACE, 2005;Verhagen et al., 2007;Verhagen et al., 2010).