1. Department of Mechanical Engineering; Korea University; Seoul 136-713 Korea
2. Department of Mechanical and Industrial Engineering; University of Illinois at Chicago; Chicago, Illinois 60607-7022 USA
3. Corporate Innovation Center; United States Gypsum; Libertyville, Illinois 600048 USA
4. School of Electrical & Electronic Engineering; Yonsei University; Seoul 120-749 Korea
5. Inst. of Adv. Composite Mat., Korea Inst. Sci & Tech; Wanju-gun, Jeonbuk 565-905 Korea
6. College of Engineering; Korea University; Seoul Korea