^{a}Division of Epidemic Intelligence Service, Korea Centers for Disease Control and Prevention, Osong, Korea
^{b}Department of Mathematics, Kyungpook National University, Daegu, Korea
^{c}Department of Preventive Oriental Medicine, Sangji University, Wonju, Korea
^{d}Korea Centers for Disease Control and Prevention, Osong, Korea
© 2011 Published by Elsevier B.V. on behalf of Korea Centers for Disease Control and Prevention.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
^{} This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.