中文摘要：

Ziyang Chen received the PhD degree in computer science from Yanshan Uni- versity, China. He is a professor of Yan- shan University and a member of China Computer Federation. His research in- terests include relational database and XML keyword search. Jia Liu received her MS degree in com- puter science from Yanshan University, China. She is currently a PhD candidate of Yanshan University. Her research in- terests include relational database and XML keyword search.E-mail： liujia78928 @ 126.com Xingmin Zhao received her MS degree in computer science from Yanshan Uni- versity, China in 2014. Her research in- terests include XML keyword search. Junfeng Zhou received the PhD degree in computer science from Renmin Uni- versity of China in 2009. He is an asso- ciate professor of Yanshan University, China and a member of China Com- puter Federation. His research interests include XML structured query process- ing and XML keyword search.