作者机构:[1]School of Computer Science and Technology, Shandong University, Jinan 250100, China
相关基金:Project Item: Supported by National Nature Science Foundation of China (61020106001, 60903109, 61103150), National Research Foundation for the Doc- toral Program of Higher Education of China (20110131130004) and Graduate Independent Innovation Foundation of Shandong University (11150071613066).