Supported partially by the National Natural Science Foundation of China (Grant No. 60833005);the National High-Tech Research & Development Program of China (Grant Nos. 2007AA01Z155, 2009AA011904);the National Basic Research Program of China (Grant No.2003CB317000)
As huge volumes of data are organized or exported in tree-structured form, it is quite necessary to extract useful information from these data collections using effective and efficient query processing methods. A natu...