作者机构:College of Computer, Nanjing University of Posts and Telecommunications, Nanjing 210003, China
相关基金:Acknowledgements This work was supported by the National Natural Science Foundation of China (60973139, 60773041), the Key Technologies R&D Program of China (2007BAK34B06), the Talent Foundation of Nanjing Universitiy of Posts and Telecommunications (NY208006).