1. Research Assistant Professor, Center for Integrated Smart Sensors, KAIST, Daejeon 34141, South Korea (corresponding author).
2. Assistant Professor, Dept. of Civil Engineering, Univ. of New Mexico, Centennial Engineering Center 3056, MSC01 1070, Albuquerque, NM 87131.
3. Professor, Dept. of Civil and Environmental Engineering, Univ. of Illinois at Urbana-Champaign, 205N. Matthews Ave., Urbana, IL 61801.