cas1
Committee
Most foreigners who want to visit Korea just for a short-term tour or transit are permitted to enter Korea with no visa according to the principles of reciprocity or priority of national interest with a tourist/transit visa status (B-2, 30 days).

For further information about visa rules:
http://english.visitkorea.or.kr/enu/GK/GK_EN_2_1_1.jsp

Letter of Invitation (for application of Visa for admission into Korea)
Participants requiring an official Letter of Invitation in order to obtain a visa and authorization to attend ISCAS 2012 should contact the Secretariat () no later than March 31, 2012. This letter is NOT a commitment on the part of ISCAS2012 Organizing Committee to provide financial assistance to any participant or accompanying persons. Expenses incurred are the sole responsibility of the participant.