School of Computer Science and Technology;
Chongqing University of Posts and Telecommunications;
Chongqing 400065;
P. R. China;
Highway Engineering Department of Chongqing Communications Research and Design Institute;
Chongqing 400067;
P. R. China;
Dept. of Computer Science & Information Engineering;
Inha University;
Incheon 402-751;
Korea;