... different from query. For ex-ample, given a query semantic web coordination”, the corresponding topic may be either semantic web or web coordination”. Similarly, person here is different from ... ways, not necessarily being identical to t. For ex-ample, both topic semantic web and semantic web search engine” can match the query semantic web search engine”. The probability is defined ... kinds of documents. For example, for web pages, we can construct the <Title> from either the ‘title’ metadata or the con-tent of web pages (Hu et al., 2006). As for e-mail, we can use...