Coll. of Information System and Management;
National Univ. of Defense Technology;
Changsha 410073;
P. R. China;
Beijing Key Lab. of Intelligent Telecommunications Software and Multimedia;
Beijing Univ. of Posts and Telecommunications;
Beijing 100876;
P. R. China;
State Key Lab. for Complex Systems Simulation;
Beijing 100101;
P. R. China;