l. Plenary address at the annual meeting of the Korean Mathematical Society, --Seoul, Republic of Korea, October 25, 1986. (40 minutes) 2. RIMS Symposium on Automorphic Forms and associated Zeta Functions, --RIMS, Kyoto University, Japan, January 6-10, 1992. (50 minutes) 3. Symposium on Infinite Root Systems and the Period Integrals, --Nakatsugawa, Japan, July 29-August 2, 1992. (1 hour) 4. Workshop on Automorphic Forms and Related Topics, --Ehwa Women's University, Seoul, Republic of Korea, September 2-3, 1993. (2 hours) 5. Plenary address at the annual meeting of the Korean Mathematical Society, --Chungju, Republic of Korea, October 23, 1994. (40 minutes) 6. Symposium on Number Theory, Geometry and Related Topics, --Pyungsan Institute for Math. Sciences, Iksan, Republic of Korea, September 23-24, 1995. (1 hour) 7. China-Korea Joint Conference on Geometry and Topology, --Academia Sinica, Peking, China, October 1995. 8. Conference on Hodge Theory and Algebraic Geometry, --Sendai, Japan, June 18-21, 1996. (1 hour) 9. International Workshop on Calabi-Yau Manifolds and Mirror Symmetry, --RIMS, Kyoto University, Japan, December 7, 9-13, 1996. (2 hours) 10. Plenary address at the annual meeting of Honam Mathematical Society, ---Iksan, Republic of Korea, June 1997. (40 minutes) 11. Invited lecture at Japan-Korea Joint Seminar on Transcendental Number Theory and Related Topics, ---Masan, Republic of Korea, November 24-25, 1997. (1 hour) 12. International Conference on Numbery Theory, Korea Institute for Advanced Study, ---Seoul, Republic of Korea, December 1997. (1 hour) 13. International Symposium on Representation Theory and Automorphic Forms, ---Seoul, Republic of Korea, February 14-17, 2005. (1 hour) 14. International Mathematics Conference on Algebras, Groups and Related Topics, Chonju, ---Republic of Korea, January 9-10, 2006. [The Artin Conjecture and Functoriality] 15. International Conference on Number Theory, Harish-Chandra Research Institute, Allahabad, India, ---December 1-5, 2006. [Remark on Harmonic Analysis on Siegel-Jacobi Space] 16. International Symposium on Automorphic Forms, L-functions and Shimura Varieties, ---Incheon, Republic of Korea, November 25-27, 2008. [Langlands Functoriality Conjecture] 17. Workshop on Invariant Theory and Related Topics, Incheon, Republic of Korea, ---February 17-19, 2010. (2 hours) [Invariant differential operators on Siegel-Jacobi space] 18. Workshop on Geometry and Representation Theory, National University of Singapore, Singapore, ---January 26-28, 2011. (1 hour) [Invariant differential operators on Siegel-Jacobi space and ---Maass-Jacobi forms] 19. International Conference on the Arithmetic of Function Fields and Related Topics, Dongguk University, ---Gyeongju, Korea, August 16-19, 2011. [Maass-Jacobi Forms] 20. International Number Theory Conference in Memory of Alf van der Poorten, March 12-16, 2012 ---- Noah’s on the Beach, Newcastle, Australia [Contributed Talk: Invariant Differential Operators on ---Siegel-Jacobi Space] 21. Invited Talks at Academy of Mathematics and Systems Science, Chinese Academy of Sciences, ---Beijing, China : August 8, 2012 [Theory of Jacobi Forms of Higher Degree], ---August 9, 2012 [Invariant Differential Operators on Siegel-Jacobi Space and Maass-Jacobi Forms] 22. International Conference on Geometry, Number Theory and Representation Theory, October 10-12, 2012, ---Incheon, Korea [Invariant Differential Operators on Siegel-Jacobi Space and Maass-Jacobi Forms] 23. International Conference on The Arithmetic of Function Fields and Related Topics, February 18-21, 2013, ---Haeundae Riviera Hotel, Busan, Korea [Some Results on Harmonic Analysis on Siegel-Jacobi Space] 24. International Conference on Geometry, Number Theory and Representation Theory, December 4-6, ---2013, NIMS Daejeon, Korea [Geometry and Arithmetic on the Siegel-Jacobi Space] 25. Mini-Workshop on Shimura Varieties and O-Minimality, June 26-27, 2014, ---Yonsei University. Seoul, Korea [Works of J. Pila, E. Ullmo, A. Yafaev et al.] 26. China-Korea Joint Seminar on Number Theory, October 2-6, 2014, ---Tsinghua Sanya International Mathematics Forum (TSIMF), Sanya, Korea ---[A Note on the Riemann-Schottky Problem]