“…Furthermore, it is not easy to select the appropriate length for the time window, since, depending on the topic intensity, the same time window will contain very different numbers of messages. Also, from the perspective of identifying bursts in the data, a set of discrete levels of intensity is preferable (Aizen et al, 2004). To overcome these problems, Kleinberg (2003) proposed a weighted automaton model (WAM), an infinite-state automaton, where each state corresponds to a particular discrete level of intensity.…”