1. Department of Mechanical Design EngineeringChosun University, 375 Seosuk-dong, Dong-gu, Gwangju 501-750, Korea
2. Department of Advanced Parts & Materials Engineering Graduate SchoolChosun University, 375 Seosuk-dong, Dong-gu, Gwangju 501-750, Korea
3. Department of Fire Protections and Safety EngineeringDongkang College 160 Dongmunro, Buk-gu, Gwangju 500-714, Korea
4. Department of Mechanical System EngineeringChosun University, 375 Seosuk-dong, Dong-gu, Gwangju 501-750, Korea