1. Center for Urban Energy Research, Korea Institute of Science and Technology; Seoul 136-791 Republic of Korea
2. Department of Energy and Environmental Engineering; University of Science and Technology; Daejeon 305-350 Republic of Korea
3. Environmental Radioactivity Assessment Team, Korea Atomic Energy Research Institute; Yuseong-gu Daejeon 305-353 Republic of Korea
4. Department of Interdisciplinary Bio-Micro System Technology, College of Engineering; Korea University; Seoul 136-701 Republic of Korea
5. Hyunjin POP; Paju-si Gyeonggi-do 10950 Republic of Korea