1. Research Fellow, Korea Rural Economic Institute; Hoigi-dong Dongdaemoon-Gu; Seoul 130-710 Korea
2. Professor, Department of Food and Resource Economics; Korea University, Anam-dong, Seongbuk-Gu; Seoul 136-701 Korea
3. Assistant Professor, Department of Food and Resource Economics; Korea University, Anam-dong, Seongbuk-Gu; Seoul 136-701 Korea
4. Professor and Tyson Endowed Chair, Department of Agricultural Economics and Agribusiness, University of Arkansas, Fayetteville, AR 72701 and Adjunct Professor, Department of Food and Resource Economics; Korea University, Anam-dong, Seongbuk-Gu; Seoul 136-701 Korea