1. Dept. of Agricultural Eng., Kyungpook National Univ., Daegu, 702-701, Republic of Korea
2. Institute Agricultural Science & Technology, Kyungpook National University, Daegu 702-701, Republic of Korea
3. Dept. of Agricultural Engg., National Academy of Agricultural Science, RDA, Jeonju, 560-500, Republic of Korea
4. Dept. of Agricultural Eng., Gyeongsang National Univ. (Institute of Agriculture and Life Science), Jinju 660-701, Korea