出处
《通讯和计算机(中英文版)》
2009年第2期29-34,共6页
Journal of Communication and Computer
基金
Acknowledgements: This work is supported by A Foundation of National Excellent Doctoral Dissertation of China (No. 200250), Natural Science Foundation of Henan Province China (No. 411012400) and National Science Foundation of China (No. 60871080).