Extraction of tag tree patterns with contractible variables from irregular semistructured data
Tetsuhiro Miyahara, Yusuke Suzuki, Takayoshi Shoudai, Tomoyuki Uchida, Sachio Hirokawa, Keníchi Takahashi, Hiroaki T. Ueda · Institutional Repositories DataBase (IRDB) · 2003
Abstract. Information Extraction from semistructured data becomes more and more important. In order to extract meaningful or interesting contents from semistructured data, we need to extract common struc-tured patterns from semistructured data. Many semistructured data have irregularities such as missing or erroneous data. A tag tree pattern is an edge labeled tree with ordered children which has tree structures of tags and structured variables. An edge label is a tag, a keyword or a wild-card, and a variable can be substituted by an arbitrary tree. Especially, a contractible variable matches any subtree including a singleton vertex. So a tag tree pattern is suited for representing common tree structured patterns in irregular semistructured data. We present a new method for extracting characteristic tag tree patterns from irregular semistruc-tured data by using an algorithm for finding a least generalized tag tree pattern explaining given data. We report some experiments of applying this method to extracting characteristic tag tree patterns from irregular semistructured data. 1