1. Ph.D. Candidate, School of Control Science and Engineering, Shandong Univ., Shandong 250061, China.
2. Ph.D. Candidate, Dept. of Civil and Environmental Engineering, Univ. of Maryland, College Park, MD 20742.
3. Professor, School of Control Science and Engineering, Shandong Univ., Shandong 250061, China (corresponding author).
4. Professor, School of Control Science and Engineering, Shandong Univ., Shandong 250061, China.