1. Department of Civil and Environmental Engineering, Virginia Tech, 415 Durham, Blacksburg 24061, Virginia, USA
2. Virginia Tech Institute of Critical Technology and Applied Science (ICTAS) Sustainable Nanotechnology Center (VTSuN), Blacksburg, Virginia, USA
3. Department of Electrical and Computer Engineering, Virginia Tech, 415 Durham, Blacksburg 24061, Virginia, USA
4. Department of Electronic Engineering, Pukyong National University, Busan, Republic of Korea