On the other hand, 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).
in TDT, an event is defined as something happening in a certain place at a certain time (Yang et al., 1999), while a topic is defined as a set of news stories related by some seminal real-world event (Allan, 2002).