### 2024

- June 24, 2024: 3rd Korea-China Young Scholar’s Symposium on Discrete Mathematics (June 24-27), UTop Ubless Hotel Jeju, Jeju, Korea.
- Linear bounds on treewidth in terms of excluded planar minors

### 2023

- November 16, 2023: 2nd Workshop on Logic, Graphs, and Algorithms (LoGAlg 2023) (November 15-17), University of Warsaw, Warsaw, Poland.
- Survey on vertex-minor obstructions and related parameters of graphs

- October 16, 2023: 2023 Vertex-Minor Workshop (October 15-20), SONO Belle Jeju, Jeju, Korea.
- Survey on vertex-minors

- September 8, 2023: East-Asia Workshop on Operations Research, Combinatorial Optimization and Algorithms (September 8-10), National Tsing Hua University, Hsinchu, Taiwan.
- Γ-graphic delta-matroids and their applications on variants of maximum spanning tree problems

- August 22, 2023: Tuesday Special Lecture (화요특강), Seoul National University Bundang Hospital, Seongnam, Korea.
- Applications of Discrete Mathematics (이산수학의 쓰임새)

- August 9, 2023: 28th KIAS Combinatorics Workshop, KIAS, Seoul, Korea.
- Reuniting 𝜒-boundedness with polynomial 𝜒-boundedness

- March 30, 2023: Colloquium, Department of Mathematics, Kyunghee University, Seoul, Korea.
- Building the hierarchy of graph classes

- January 28, 2023: Workshop on Graph Coloring and Related Topics (January 28-29), Konkuk University, Seoul, Korea.
- Improper colorings regarding Hadwiger’s conjecture

### 2022

- December 19, 2022: 2022 BrainLink – Combinatorial Algebraic Geometry (2022 우수연구자교류지원 기술교류회 – 조합 대수기하학 국제교류회), Korean Federation of Science and Technology Societies (한국과학기술단체총연합회), Sheraton Grand Incheon Hotel, Incheon, Korea.
- Γ-graphic delta-matroids and their applications

- December 5, 2022: Sejong Academy of Science and Arts (세종과학예술영재학교), Sejong, Korea.
- 과학고에서 대학교수까지

- December 2, 2022: International Conference on Matrix Theory with Applications to Combinatorics, Optimization and Data Science (December 1-5), Seogwipo KAL Hotel Jeju, Jeju, Korea.
- Γ-graphic delta-matroids and their applications

- December 1, 2022: Colloquium, Department of Mathematics, Hanyang University, Seoul, Korea.
- Building the hierarchy of graph classes

- November 11, 2022: Combinatorics Today Series 2022, Institut Teknologi Bandung, Online, Indonesia.
- November 4, 2022: Fields Symposium, POSTECH, Pohang, Korea.
- October 20, 2022: 2022 Global KMS International Conference (October 18-21), Seoul, Korea.
- August 19, 2022: Workshop on Graph Theory and Combinatorics in Memory of Robin Thomas (August 19-21), Georgia Institute of Technology, Atlanta, USA.
- Building the hierarchy of graph classes

- July 25, 2022: 8th Czech-Slovak International Symposium on Graph Theory, Combinatorics, Algorithms and ApplicationsDedicated to the Memory of Robin Thomas (July 25-29), Charles University, Prague, Czech.
- Building the hierarchy of graph classes

- July 23, 2022: Special Lecture, Busan National Science Museum, Busan, Korea.
- 필즈상 수상 기념 특별 강연

- June 23, 2022: Seymour 70+x workshop (June 20-24), ENS de Lyon, Lyon, France.
- Independent domination of graphs with bounded maximum degree

- May 31, 2022:
*Korea-Taiwan-Vietnam Joint Seminar in Combinatorics and Analysis*, Online, Vietnam.- Building the hierarchy of graph classes

- March 18, 2022:
*39th International Symposium on Theoretical Aspects of Computer Science (STACS 2022)*(March 15-18), Online, Marseille, France.- Obstructions for matroids of path-width at most k and graphs of linear rank-width at most k

- March 8, 2022: Graphs and Matroids Seminar, The Matroid Union, Online.
- Obstructions for matroids of path-width at most k and graphs of linear rank-width at most k

- February 28, 2022: Discrete Math Seminar, IBS Discrete Mathematics Group, Daejeon, Korea.
- Obstructions for matroids of path-width at most k and graphs of linear rank-width at most k

- February 25, 2022: SCMS Combinatorics Seminar, Shanghai Center for Mathematical Sciences, Fudan University, Shanghai, China.
- Independent domination of graphs with bounded maximum degree

- February 22, 2022: 24th KIAS Combinatorics Workshop (February 22-24), Shilla Stay Haeundae, Busan, Korea.
- Building the hierarchy of graph classes

- February 17, 2022: Industrial Mathematics Colloquium (산업수학콜로퀴움), NIMS ICIM, Suwon, Korea.
- Building the hierarchy of graph classes

- January 6, 2022: Oberwolfach workshop on Graph Theory (January 2-8), Mathematisches Forschungsinstitut Oberwolfach (MFO), Oberwolfach, Germany.

### 2021

- November 11, 2021: 2021 China-Korea Young Scholars’ Symposium on Discrete Mathematics, Statistics and Optimization, Tianjin-SIAM / Nankai University / The State University of New York, Korea / Tianjin Science and Technology Association, Online, Korea & China.
- Obstructions for graphs of linear rank-width at most k

- November 4, 2021: AlGCo Seminar, Département Informatique, LIRMM, Montpellier, France.
- Obstructions for matroids of path-width at most k and graphs of linear rank-width at most k

- October 8, 2021: Graz Combinatorics Seminar, Technical University of Graz, Graz, Austria. Online.
- Obstructions for graphs of linear rank-width at most k

- July 22, 2021: Minisymposium on Graph Structure, SIAM Conference on Discrete Mathematics (July 20-23), Online, Spokane, USA.
- Obstructions for bounded shrub-depth and rank-depth of graphs

- April 20, 2021: Discrete Math Seminar, IBS Discrete Mathematics Group, Daejeon.
- What is an isotropic system?

- April 9, 2021: Bordeaux Graph Seminar, LaBRI, Bordeaux, France.
- A unified half-integral Erdős-Pósa theorem for cycles in graphs labelled by multiple abelian groups

### 2020

- December 14, 2020: The 31st International Symposium on Algorithms and Computation (ISAAC’20), Online, Hong Kong. (December 14-18) (invited talk)
- How to decompose a graph into a tree-like structure

- November 27, 2020: 2020 KEDI Job Training for teachers in charge of gifted education (영재교육 담당교원 전문성강화 직무연수), Daegu, Korea. (Online).
- 영재교육경험담

- November 5, 2020: Séminaire virtuel de théorie des graphes et combinatoire en Rhône-Alpes et Auvergne, France. (Online).
- Obstructions for bounded shrub-depth and rank-depth of graphs

- April 21, 2020: Discrete Math Seminar, IBS Discrete Mathematics Group, Daejeon.
- Survey on vertex-minors

- March 19, 2020: New Perspectives in Colouring and Structures, Banff International Research Station, Banff, Canada. (Online). (March 15-20)
- 3-degenerate induced subgraphs of a planar graph

### 2019

- October 27, 2019: 2019 KMS Annual Meeting, Hongik University, Seoul. (October 25-27)
- The Erdős-Hajnal property for graphs with no fixed cycle as a pivot-minor

- October 19, 2019: The 4th IBS-CGP Public Lecture (제4회 IBS 기하학 수리물리 연구단 수학 문화 강연), IBS Center for Geometry and Physics, Pohang.
- 잘 다니기: 어떻게 최적인 방법을 찾을까

- September 24, 2019: The 9th Workshop on Graph Classes, Optimization, and Width Parameters (GROW 2019), TU Wien, Vienna (September 23-26)
- Branch-depth: Generalizing tree-depth of graphs

- August 1, 2019: 2019 IBS Summer Research Program on Algorithms and Complexity in Discrete Structures, IBS Discrete Mathematics Group, Daejeon
- Branch-depth: Generalizing tree-depth of graphs

- July 4, 2019: Graph Colouring: from Structure to Algorithms, Dagstuhl Workshop, Dagstuhl, Germany.
- The Erdős-Hajnal property for graphs with no fixed cycle as a pivot-minor

- June 6, 2019: International Conference on Network Games, Tropical Geometry, and Quantum Communication, Berlin Mathematics Research Center MATH+, Zuse Institute of Berlin, Berlin, Germany.
- Survey on vertex-minors

- May 28, 2019: Mini-symposium “structural graph theory”, CanaDAM 2019, Vancouver, Canada.
- The Erdős-Hajnal property for graphs with no fixed cycle as a pivot-minor

- May 1, 2019: Structural Graph Theory and Graph Coloring, Tsinghua Sanya International Mathematics Forum, Sanya, China. (April 29-May 3)
- Branch-depth: Generalizing tree-depth of graphs

- April 20, 2019: Plenary Lecture, 2019 KMS Spring Meeting, Kangwon National University, Chuncheon.
- How to decompose a graph into a tree-like structure

- April 16, 2019: PCS Seminar, Center for Theoretical Physics of Complex Systems, Institute for Basic Science, Daejeon.
- How to decompose a graph into a tree-like structure

- March 31, 2019: 2019 Spring Jinhua Workshop on Graph Theory, Zhejiang Normal University, Jinhua, China.
- Branch-depth: Generalizing tree-depth of graphs

- March 28, 2019: Colloquium, GIST College, GIST, Gwangju.
- 4색정리 이야기

- March 22, 2019: Special Session on Structural Graph Theory, AMS Spring Central and Western Joint Sectional Meeting, University of Hawaiʻi at Mānoa, Hawaii, USA.
- Classes of graphs with no long cycle as a vertex-minor are polynomially 𝜒-bounded

- March 15, 2019: 대구과학고 아카데미 강연, Daegu Science High School, Daegu.
- February 21, 2019: Taipei International Workshop on Combinatorics and Graph Theory, Institute of Mathematics, Academia Sinica, Taipei, Taiwan
- Classes of graphs with no long cycle as a vertex-minor are polynomially 𝜒-bounded

### 2018

- December 1, 2018: 2018 SCMS Workshop on Extremal and Structural Graph Theory, Shanghai Center for Mathematical Sciences, Fudan University, Shanghai, China
- Classes of graphs with no long cycle as a vertex-minor are polynomially 𝜒-bounded

- November 24, 2018: 2018 Pohang Mathematics Workshop, The Ocean Resort, Yeosu
- Vertex-minors and pivot-minors of graphs

- November 3, 2018: KSIAM 2018 Annual Meeting, Ramada Hotel, Jeju
- Classes of graphs with no long cycle as a vertex-minor are polynomially 𝜒-bounded

- August 20-23, 2018: KIAS-AORC Joint Workshop (21st KIAS Combinatorics Workshop), Elysian Gangchon, Chuncheon
- Introduction to Graph Theory (Lecture series)

- August 6, 2018: 2018 IBS Symposium on Combinatorics, Chung-And University, Seoul
- Survey on vertex-minors and pivot-minors of graphs

- June 5, 2018: Mini-symposium “Graph Structure Theory”, SIAM Conference on Discrete Mathematics, Denver, CO, USA
- Scattered classes of graphs

- April 19, 2018: Princeton Discrete Math Seminar, Princeton University, Princeton, NJ, USA
- Finding branch-decompositions of matroids, hypergraphs, and more

- March 24, 2018: Gyeongsangbuk-do Office of Education Science Gifted Education Center, Pohang
- 잘 칠하기 — 4색 정리, 그래프 이론, 조합적 최적화

- January 5, 2018: 2018 International Workshop on Graph Theory, Ewha Womans University, Seoul
- Properties of intersecting families of ordered sets: revisited

### 2017

- December 18, 2017: KIAS Combinatorics Workshop, Novotel, Busan
- Finding branch-decompositions of matroids, hypergraphs, and more

- December 16, 2017: 2017 Korea-China International Conference on Matrix Theory with Applications, Sungkyunkwan University, Suwon
- Properties of intersecting families of ordered sets: revisited

- October 12, 2017: GROW2017: Workshop on Graph Classes, Optimization, and Width Parameters, Fields Institute, Toronto, Canada
- Chi-boundedness of graph classes excluding wheel vertex-minors

- August 21, 2017: Geometric and Structural Graph Theory, BIRS, Banff, Canada
- August 16, 2017: 2017 Combinatorics Workshop, Sungkyunkwan University, Suwon
- Chi-boundedness of graph classes excluding wheel vertex-minors

- June 2, 2017: KIAS Combinatorics Workshop, KIAS, Seoul
- On the slice rank method

- April 29, 2017: 2017 KMS Spring Meeting, Chosun University, Gwangju.
- Unavoidable induced subgraphs in large graphs with no homogeneous sets

### 2016

- November 11, 2016: KSIAM 2016 Annual Conference, Seogwipo KAL Hotel, Jeju
- Defective coloring of graphs with excluded subgraphs

- October 28, 2016: AORC Group 1 Colloquium, Department of Mathematics, Sungkyunkwan University, Suwon
- Rank-width: Algorithmic and Structural Results

- September 26, 2016: The Southern Italian Workshop on Algorithms and Graphs, Italy
- Defective coloring of graphs with excluded subgraphs

- June 16, 2016: Workshop on Probabilistic and Extremal Combinatorics Downunder, Monash University, Melbourne, Australia.
- Variants of Hadwiger’s conjecture

- April 7, 2016: Colloquium, Depasrtment of Mathematics, Yonsei University, Seoul.
- 4색정리를 포함하는 Hadwiger의 추측의 변형에 관하여

- March 24, 2016: Colloquium, Department of Mathematics, Ewha Womans University, Seoul.
- 4색정리를 포함하는 Hadwiger의 추측의 변형에 관하여

- February 19, 2016: 2016 International Workshop on Graph Theory and Combinatorics, Ewha Womans University, Seoul.
- Variants of Hadwiger’s conjecture

- January 19, 2016: “Distributed algorithms and graphs” Seminar, Laboratoire d’Informatique Algorithmique: Fondements et Applications (LIAFA), Université Paris Diderot, Paris, France.
- Variants of Hadwiger’s conjecture

### 2015

- December 15, 2015: Séminaires, Laboratoire d’Informatique, de Modélisation et d’Optimisation des Systèmes, ISIMA (Institut Supérieur d’Informatique, de Modélisation et de leurs Applications), Université Blaise Pascal, Aubiere, France.
- Variants of Hadwiger’s conjecture

- December 7, 2015: Graph Theory in the Andes, Los Andes, Chile.
- Improper coloring and the odd Hadwiger’s conjecture

- November 1, 2015: 2015 International Workshop on Mathematical Sciences in Dalian, Dalian University of Technology, Dalian, China
- Constructive algorithm for path-width of matroids

- October 27, 2015: Colloquium, Department of Mathematics, Choongnam National University, Daejeon.
- 4색정리를 포함하는 Hadwiger의 추측의 변형에 관하여

- October 13, 2015: GROW 2015 :the 7th workshop on Graph Classes, Optimization, and Width Parameters (October 11-15), Aussois, France.
- Constructive algorithm for path-width of matroids

- August 26, 2015: 1st Korean Workshop on Graph Theory, KAIST.
- Counting cliques in graphs with a forbidden subdivision

- August 10, 2015: Extremal Combinatorics, Probabilistic Combinatorics, and their applications, The 8th International Congress on Industrial and Applied Mathematics (ICIAM 2015), Beijing, China.
- Counting cliques in graphs with forbidden subdivision

- July 13, 2015: 2015 Combinatorics Workshop, NIMS, Daejeon.
- Strongly even-cycle decomposable graphs

- June 17, 2015: Algorithmic Graph Theory on the Adriatic Coast (16-19 June 2015), Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Koper, Slovenia.
- Constructive algorithm for rank-width of graphs and path-width/branch-width of matroids

- May 14, 2015: Colloquium, Department of Mathematical Sciences, Seoul National University, Seoul.
- 4색정리를 포함하는 Hadwiger의 추측의 변형에 관하여

- March 13, 2015: 7th KIAS Combinatorics Workshop, KIAS, Seoul.
- Partitioning H-minor-free graphs into three subgraphs with no large components

- January 29, February 5, 12, 2015:KAIST 명강 4기, Seoul.
- 잘 짝지우기 (January 29)
- 잘 칠하기 (February 5)
- 잘 다니기 (February 12)

- January 19, 2015: International Workshop on Graph Decomposition, CIRM, Luminy, France.
- Constructive algorithm for path-width and branch-width of matroids and rank-width of graphs

### 2014

- November 27, 2014: Colloquium, Department of Mathematics, Duksung Women’s University, Seoul.
- From the Four Color Theorem to Hadwiger’s Conjecture

- November 14, 2014: Colloquium, Department of Mathematics, Korea University, Seoul.
- Ramsey-type theorem for graphs without splits

- July 21, 2014: 2014 International Workshop on Structure in Graphs and Matroids, Princeton University, Princeton, NJ, USA.
- Constructive algorithm for path-width and branch-width of matroids

- July 5, 2014: 수학골든벨 KAIST 프로그램, KAIST, Daejeon.
- Road to become a mathematician (수학자의 길에 관한 이야기)

- July 5, 2014: Institute of Science Education for the Gifted (과학영재교육원), Choongnam National University, Daejeon.
- Infinite numbers (무한)

- June 27, 2014: KMRS Seminar, Department of Mathematical Sciences, KAIST, Daejeon.
- An algorithm for path-width and branch-width of matroids

- June 16, 2014: Minisymposium “Graph Structure – Part I of II”, SIAM Conference on Discrete Mathematics, Minneapolis, MN, USA.
- Unavoidable vertex-minors in large prime graphs

- April 18, 2014: Colloquium, Department of Mathematics, POSTECH, Pohang.
- Ramsey-type theorem for graphs without splits

- March 13, 2014: Colloquium, Department of Mathematics, Sogang University, Seoul.
- Ramsey-type theorem for graphs without splits

- March 8, 2014: 3rd KIAS Combinatorics Workshop, KIAS, Seoul.
- Unifying duality theorems for width parameters

- January 28, 2014: Working Group Seminar, University of Hamburg, Hamburg, Germany (with Reinhard Diestel).
- Unifying duality theorems for width parameters in finite graphs

- January 14, 2014: Working Group Seminar, University of Hamburg, Hamburg, Germany.
- Hyperbolic surface subgroups of one-ended doubles of free groups

### 2013

- December 16, 2013: Monday Lecture, Institut für Mathematik, Technische Universität Berlin, Berlin, Germany.
- Vertex-minors and split decompositions of graphs

- November 14, 2013: Institutskolloquium, Institut für Informatik, University of Rostock, Rostock, Germany.
- Vertex-minors of graphs

- October 1, 2013: DIMAP Seminar, Center for Discrete Mathematics and its Applications, University of Warwick, UK.
- Vertex-minors of graphs

- July 1, 2013: Special Session on Combinatorics and Graph Theory, the Asian Mathematical Conference AMC2013 (June 30-July 4), Busan, Korea.
- Excluded vertex-minors for graphs of linear rank-width at most k

- June 24, 2013: Special Session on Combinatorics and Discrete Mathematics, 2nd Pacific Rim Mathematical Association Congress (June 24-28), Shanghai, China.
- June 5, 2013: Working Group Seminar, University of Hamburg, Hamburg, Germany (with O-joung Kwon).
- Unavoidable vertex-minors for large prime graphs

- April 19, 2013: Research Seminar, University of Hamburg, Hamburg, Germany.
- Width-parameters and tree-decompositions of graphs and matroids

- April 14, 2013: Vortrag im Seminar Diskrete Mathematik und Optimierung, Institut für Optimierung und Diskrete Mathematik, Technische Universität Graz, Graz, Austria.
- Even cycle decompositions of graphs with no odd K
_{4}minor

- Even cycle decompositions of graphs with no odd K
- March 20, 2013: Dagstuhl workshop “Bidimensional Structures: Algorithms, Combinatorics and Logic” (March 17-22), Schloss Dagstuhl, Dagstuhl, Germany.
- Forbidden vertex-minors for graphs of linear rank-width at most k

- February 21, 2013: Working Group Seminar, University of Hamburg, Hamburg, Germany
- Vertex-minors and pivot-minors, concepts and overview

- January 30, 2013: グラフ・ネットワークにおける理論と最適化グループセミナー (Graph Network Theory and Optimization Group Seminar), National Institute of Informatics, Tokyo, Japan.
- Well-quasi-ordering conjecture for pivot-minors

- January 22, 2013: KAIST 글로벌 사이언스 리더 캠프 (2012학년도 부산광역시 과학영재교육원 겨울집중수업), KAIST 영재교육센터.
- 짝지우기, 그래프 이론, 수학

### 2012

- December 7, 2012: KAIST 일반전형 창의인성면접자 합격생 워크샵 및 멘토링 프로그램, KAIST.
- KAIST 선배의 경험담

- November 15, 2012: 자연과학강좌, Chungbuk National University, Cheongju.
- 4색 정리 이야기 (Story on Four Color Theorem)

- October 27, 2012: 2012 International Conference on Graph Theory, Combinatorics and Applications (October 27-30), Zhejiang Normal University, Jinhua, China.
- Even cycle decomposition of graphs with no odd K
_{4}minor

- Even cycle decomposition of graphs with no odd K
- October 18, 2012: Discrete Convexity and Optimization (October 15-18), RIMS Workshop, Kyoto, Japan.
- Even cycle decomposition of graphs with no odd K
_{4}minor

- Even cycle decomposition of graphs with no odd K
- October 5, 2012: Invited talk, 2012 KMS Fall Meeting (October 5-6), Daejeon.
- Even cycle decomposition of graphs with no odd K
_{4}minor

- Even cycle decomposition of graphs with no odd K
- August 20, 2012: Invited session on structural graph theory and methods, 21st International Symposium on Mathematical Programming (August 19-24), Berlin, Germany.
- July 24, 2012: 젊은 지성과의 만남, 영스타클럽(Korean Science and Technology Young Stars Club) 포럼 (July 24-25, 2012), KAIST
- August 3, 2012: Third workshop on graphs and matroids (July 29-August 4), Maastricht, The Netherlands
- Even cycle decomposition of graphs with no odd K
_{4}minor

- Even cycle decomposition of graphs with no odd K
- June 19, 2012: SIAM Conference on Discrete Mathematics(June 18-21), Dalhousie University, Halifax, Nova Scotia, Canada.
- Rank-Width and Well-Quasi-Ordering of Skew-Symmetric Or Symmetric Matrices

- June 1-7, 2012: Mini-school on Widths-Minors-Matroids, Department of Informatics, University of Bergen, Bergen, Norway.
- June 1: Relation of rank-width with clique-width
- June 4: Rank-width and vertex-minors; their relations to binary matroid minors
- June 5: Branch-width of symmetric submodular functions and their recognition algorithms
- June 6: Excluded pivot-minors for rank-width
- June 7: Isotropic systems and vertex-minors; how to write C2MS logic formula for testing vertex-minors

- May 9, 2012: Graph Theory @ Georgia Tech, Conference Honoring the 50th Birthday of Robin Thomas (May 7-11), Georgia Tech, Atlanta, USA.
- Graphs of small rank-width is a pivot-minor of graphs of small tree-width

- April 12, 2012: Colloquium, Department of Mathematics, Chonbuk National University, Jeonju, Korea.
- Survey on vertex-minors and pivot-minors

### 2011

- December 14, 2011: The Second Bertinoro Workshop on Algorithms and Graphs, Bertinoro, Italy.
- Rank-width and well-quasi-ordering of skew-symmetric or symmetric matrices

- November 8, 2011: Robin Thomas Fest, Charles University, Prague, Czech.
- Rank-width and well-quasi-ordering of skew-symmetric or symmetric matrices

- October 18, 2011: Seminar, Department of Computer Science and Engineering, Seoul National University, Seoul.
- Vertex-minors, Monadic Second-Order Logic, and a Conjecture by Seese

- September 2, 2011: European Conference on Combinatorics, Graph Theory, and Applications (Eurocomb), Budapest, Hungary.
- Rank-width and well-quasi-ordering of skew-symmetric or symmetric matrices

- August 18, 2011: Combinatorics Workshop (2011 조합론 학술대회), Kangwon National University, Chuncheon.
- Computing Rank-width Exactly

- August 4, 2011: 2011 초등 수학과학 영재교사 직무연수, 충남대학교 과학영재교육원, Choongnam National University, Daejeon.
- 4색 정리 이야기 (Story on Four Color Theorem)

- June 28, 2011: Noon Lecture, Department of Applied Mathematics (KAM), Charles University, Prague.
- Vertex-minors and pivot-minors of graphs

- June 10, 2011: Special Department Seminar, Department of Mathematics, Yeungnam University, Kyoungsan.
- A survey on vertex-minors and pivot-minors

- April 29, 2011: Special Session on Graph Theory, Korean Mathematical Society Spring Meeting, Korea University, Seoul.
- Rank-width and Well-quasi-ordering of Skew-symmetric or Symmetric Matrices

- April 19, 2011: 자연과학대학 대중강연 (Public Lecture of College of Natural Science), KAIST.
- 4색정리 이야기 (Story on Four Color Theorem)

- April 11, 2011: 유학준비생을 위한 강연, KAIST.
- February 16, 2011: Graph Algorithm and Combinatorial Optimization, NII Shonan Meeting, Shonan Village Center, Japan.
- Rank-width and Well-quasi-ordering of Skew-symmetric or Symmetric Matrices

### 2010

- December 3, 2010: Public Lecture, 금요일에 과학터치, 대전교육과학연구원, Daejeon.
- Mathematics of Matchings (짝지우기의 수학)

- November 17, 2010: Kyoto Prize Satellite Workshop in Tokyo in honor of Professor László Lovász, Tokyo Institute of Technology, Tokyo.
- Hyperbolic surface subgroups of doubles of free groups

- September 9, 2010: New trends on structural graph theory, Banff Workshop, Banff, Canada.
- Hyperbolic surface subgroups of doubles of free groups

- August 25, 2010: 대구과학고 아카데미 강연, Daegu Science High School, Daegu.
- August 23, 2010: Robot Vision 연구회 세미나, Samsung 생산기술연구소, Suwon.
- 그래프이론 소개 (Introduction to Graph Theory)

- August 20, 2010: Invited Talk, 2010 Combinatorics Workshop, Yeungnam University, Gyeongsan
- Hyperbolic surface subgroups of one-ended doubles of free groups

- August 13, 2010: Invited Lecture, KAIST 수학문제연구회 영재캠프, KAIST, Daejeon
- Mathematics of Matchings (짝지우기의 수학)

- June 21, 2010: 40th Algebraic Combinatorics Seminar, Kyungpook National University, Daegu.
- Well-quasi-ordering conjecture for pivot-minors

- June 16, 2010: Minisymposium on Structural Graph Theory, SIAM Conference on Discrete Mathematics, Austin, Texas, USA.
- Perfect matchings in claw-free cubic graphs

- April 24, 2010: Lecture for KMS Excellent Paper Award, KMS Spring Meeting, Korean Mathematical Society, Choongnam National University, Daejeon.
- Vertex-minors, monadic second-order logic, and a conjecture by Seese

- April 24, 2010, Invited Public Lecture, Korean Women in Mathematical Society (한국여성수리과학회), Choongnam National University, Daejeon.
- Mathematics of Matchings (짝지우기의 수학)

- April 17, 2010: The 3rd Annual Meeting of the Asian Association for Algorithms and Computation (AAAC2010), POSTECH, Pohang.
- Computing rank-width exactly

- March 24, 2010: Invited Seminar, National Institute of Mathematical Sciences (NIMS), Daejeon.
- Rank-width of Random Graphs

- February 15-19, 2010: One-Week Workshop on New Development of Discrete Algorithms, Tokyo Institute of Technology, Tokyo, Japan.
- (2/15) Testing branch-width at most k for fixed k or non-fixed k

- February 10, 2010: The First Wednesday Multidisciplinary Forum (첫수융합포럼), KAIST.
- Matchings

- January 11-13, 2010: Winter School on Algorithms and Combinatorics, Jochiwon, Korea.
- (1/12) Parameterized Complexity
- (1/13) Width Parameters of Graphs

### 2009

- December 19, 2009: Special session on combinatorial matrix theory, Joint Meeting of the Korean Mathematical Society and the American Mathematical Society, Ewha Womans University, Seoul.
- Perfect matchings in claw-free cubic graphs

- December 17, 2009: Parameterized complexity and approximation algorithms, Dagstuhl, Germany.
- Algorithms on Rank-width

- December 10, 2009: Bertinoro Workshop on Graphs and Algorithms, Bertinoro, Italy.
- Perfect matchings in claw-free cubic graphs

- October 20, 2009: Informatics Colloquium, Faculty of Informatics, Masaryk University, Brno, Czech Republic.
- Maximum number of complete subgraphs in a certain graph

- October 16, 2009: Fourth workshop on Graph Classes, Optimization, and Width Parameters (GROW 2009), Bergen, Norway.
- Computing rank-width exactly

- September 17, 2009: Colloquium, Department of Mathematics, Sungkyunkwan University, Suwon, South Korea.
- Vertex-minors and pivot-minors of graphs

- June 8, 2009: 첨단과학세미나, Korea Science Academy (한국과학영재학교), Pusan, South Korea.
- Planar graphs and circle graphs

- June 4, 2009: 2009 ASARC Workshop, Muju resort, South Korea.
- A survey on vertex-minors and pivot-minors

- May 9, 2009: DIMACS Workshop on Graph Colouring and Structure, Princeton University, Princeton, New Jersey, USA.
- April 25, 2009: 2009 KMS Spring Meeting, Department of Mathematis, Ajou University, Suwon, South Korea.
- Maximum number of complete subgraphs in a certain graph

- February 4, 2009: KAIST Combinatorics Seminar, Department of Mathematical Sciences, KAIST, Daejeon, South Korea.
- Maximum number of complete subgraphs in a certain graph

- January 30, 2009: 2009 ASARC Workshop at Daecheon, Daecheon, South Korea.
- Maximum number of complete subgraphs in a certain graph

- January 9, 2009: Seminar, Department of informatics, University of Bergen, Bergen, Norway.
- Maximum number of complete subgraphs in a certain graph

- January 8, 2009: Department Seminar, Department of informatics, University of Bergen, Bergen, Norway.
- Introduction to Rank-width

### 2008

- December 22, 2008: Kyoto RIMS Winter School on Graphs and Algorithms, RIMS, Kyoto University, Kyoto, Japan.
- Survey on Rank-width and Clique-width

- November 5, 2008: Math Club, Department of Mathematics, POSTECH
- Seese’s conjecture on the decidability of the monadic second-order theory

- November 1, 2008: 수학문제연구회 20주년 기념행사 (20th year anniversary event of KAIST Mathematical Problem Solving Group), KAIST Mathematical Problem Solving Group, KAIST.
- 그래프 집합 위에서의 단항이차논리식의 결정가능성에 관한 Seese의 추론

- October 16, 2008: Colloquium, Department of Mathematics, Ajou University, Suwon, Korea.
- Seese’s conjecture on the decidability of the monadic second-order theory

- September 30, 2008: Graph minors, Banff International Research Station, Banff, Canada.
- Tree-width and rank-width of H-minor-free graphs

- August 7, 2008: 2008 Combinatorics Workshop, Sungkyungkwan University, Suwon, Korea.
- Finding branch-decompositions and rank-decompositions.

- July 20, 2008: The Netherlands Workshop on Graphs and Matroids, Sittard, the Netherlands.
- Graphic delta-matroids

- June 24, 2008: Fudan-KAIST Joint Workshop on Applied Mathematics, School of Mathematical Sciences, Fudan University, Shanghai, China.
- Chain theorems for 4-prime graphs

- June 16, 2008: SIAM Conference on Discrete Mathematics, University of Vermont, Burlington, Vermont, USA.
- Chain theorems for 4-prime graphs

- June 12, 2008: Kyoto RIMS Workshop on Combinatorial Optimization and Discrete Algorithms, Research Institute for Mathematical Sciences (RIMS), Kyoto University, Kyoto, Japan.
- April 7, 2008: Workshop on Graph Decomposition: Theoretical, Algorithmic and Logical Aspects, CIRM, Luminy, France.
- April 3, 2008: Combinatorics Seminar, LaBRI, Bordeaux, France.
- Line graphs of large rank-width

- March 28, 2008: Special session on Structural graph theory, AMS sectional meeting, Baton Rouge, Lousiana, USA.
- Chain theorems for 4-prime graphs

- February 21, 2008: Undergraduate Colloquium (학부생 콜로퀴엄), Department of Mathematical Sciences, KAIST.
- Four Color Theorem

- February 1, 2008: 4th Korea-Japan Workshop on Algebra and Combinatorics, POSTECH, Pohang, Korea.
- Well-quasi-ordering of skew-symmetric matrices of bounded rank-width

### 2007

- December 3, 2007: Colloquium, Department of Computational and Applied Mathematics, Rice University, Houston, Texas, USA.
- Introduction to Rank-wdth

- November 27, 2007: Combinatorial Optimization Seminar, University of Waterloo, Waterloo, Ontario, Canada.
- Finding Branch-decompositions and Rank-decompositions

- November 16, 2007: Joint Combinatorics – Theory Seminar, University of Toronto, Toronto, Canada.
- Introduction to Rank-width

- October 19, 2007: The Third Workshop on Graph Classes, Optimization, and Width Parameters, Eugene, Oregon, USA.
- August 6-8, 2007: 2007 Combinatorics Workshop, KAIST, Daejeon, Korea.
- Circle graphs obstructions under pivoting (August 6)
- Excluding a bipartitie circle graph from line graphs (August 7)
- Rank-width and well-quasi-ordering (August 8 )

- July 25, 2007: Structure Theory and FPT Algorithms for Graphs, Digraphs and Hypergraphs, Dagstuhl workshop 07281, Germany.
- May 28, 2007: 1st Canadian Discrete and Algorithmic Mathematics Conference (CanaDAM 2007), Banff, Alberta, Canada.
- Circle graph obstructions under pivoting

- May 10, 2007: Colloquium, Department of Mathematics, Yonsei University, Seoul, Korea.
- Survey on rank-width and clique-width

- May 8, 2007: Special Lecture, Department of Mathematics, POSTECH, Pohang, Korea.
- Survey on rank-width and clique-width

- May 2, 2007: Colloquium, Department of Mathematical Sciences, KAIST, Daejeon, Korea.
- Survey on rank-width and clique-width

- March 28, 2007: Oberwolfach Workshop
*Graph Theory*, Oberwolfach, Germany.- Excluded pivot-minor characterization of circle graphs

- January 23, 2007: Combinatorial Optimization Seminar, University of Waterloo, Canada.
- Circle graph obstructions under pivoting

### 2006

- November 16, 2006: Graph Theory Seminar, Georgia Institute of Technology, USA.
- Circle graph obstructions under pivoting

- August 4, 2006: Tutte Seminar, University of Waterloo, Canada.
- Survey on rank-width and clique-width

- July 21, 2006: Horizon of Combinatorics, Lake Balaton, Hungary.
- Excluding a bipartite circle graph from line graphs

- July 11, 2006: Sixth Czech-Slovak International Symposium on Combinatorics, Graph Theory, Algorithms and Applications, Prague, Czech Republic.
- Excluding a bipartite circle graph from line graphs

- June 25, 2006: SIAM Conference on Discrete Mathematics, Victoria, British Columbia, Canada.
- Towards a Grid Theorem for Rank-width and Clique-width

- May 20, 2006: The XXVIIIth Ohio State-Denison Mathematics Conference, Columbus, OH, USA.
- Towards a Grid Theorem for Rank-width and Clique-width

- April 27, 2006: Graph Theory Seminar, Georgia Institute of Technology, USA.
- Towards a Grid Theorem for Rank-width and Clique-width

- February 9, 2006: Graph Theory Seminar, Georgia Institute of Technology, USA.
- Testing Branch-width

- January 23, 2006: ACM/SIAM Conference on Discrete Algorithms (SODA), Miami, FL, USA.

### 2005

- December 27, 2005: Combinatorics Seminar, Department of Mathematics, KAIST, Daejeon, Korea.
- November 24, 2005: Combinatorics and Optimization Seminar, University of Waterloo, Waterloo, Canada.
- Testing Branch-width

- October 18, 2005: Workshop on Graph Classes, Width Parameters and Optimization, Prague, Czech.
- October 13, 2005: Graph Theory Seminar, Georgia Institute of Technology, USA.
- Graphs of Bounded Rank-width II

- October 12, 2005: Combinatorics Seminar, Georgia Institute of Technology, USA.
- Rank-width and Well-quasi-ordering of Skew-symmetric Matrices

- October 6, 2005: Graph Theory Seminar, Georgia Institute of Technology, USA.
- Graphs of Bounded Rank-width

- September 24, 2005: The 41st Midwest Graph Theory Conference, Middle Tennessee State University, Murfreesboro, TN, USA.
- Approximating Rank-width and Clique-width Quickly

- September 13, 2005: 7th International Colloquium on Graph Theory (ICGT ’05), Hyères, France.
- Rank-width and well-quasi-ordering of skew-symmetric matrices

- July 26, 2005: Exact Algorithms and Fixed-Parameter Tractability, Dagstuhl workshop, Germany.
- July 3, 2005: Princeton-Oxford Workshop, Oxford, UK.
- June 23, 2005: 31st International Workshop on Graph-Theoretic Concepts in Computer Science, Metz, France.
- June 20, 2005: Seminar on graphs and logic, University of Bordeaux 1, Bordeaux, France.
- Graphs of Bounded Rank-width

- June 16, 2005: Séminaire de Combinatoire Algébrique et Géométrique, Combinatoire et Optimisation, Université Pierre et Marie Curie (Paris 6), Paris, France
- January 19, 2005: Oberwolfach Workshop “
*Graph Theory*“, Oberwolfach, Germany

### 2004

- December 17, 2004: Workshop “
*Graph and Hypergraph Decompositions – Methods and Applications in Computer Science*“, Vienna, Austria - November 19, 2004: PACM Graduate Student Seminar, Princeton University
- Rank-width and Well-quasi-ordering

- November 15, 2004: Discrete Mathematics and Optimization Seminar, McGill University, Montreal, Quebec, Canada
- October 29, 2004: Graph Theory Seminar, Georgia Institute of Technology
- October 1-2, 2004: two talks were given at the Satellite Workshop
*Logic, Graph Transformations, Finite and Infinite Structures*of the 2nd International Conference on Graph Transformations (IGCT) in Rome, Italy. Titles are - May 25, 2004:
*Robust and Approximative Algorithms on Particular Graph Classes*, a Dagstuhl seminar - March 10, 2004:
*Princeton Discrete Mathematics Seminar*- From binary matroids to graphs

- February 27, 2004:
*PACM Graduate Student Seminar*- From binary matroids to graphs

### 2003

- December 13, 2003:
*Advances in Graph and Matroid Theory*, A conference in honour of Neil Robertson’s 65^{th}birthday - June 25-28, 2003:
*Oxford/Princeton Workshop*- Approximating Clique-width

- March 28, 2003:
*PACM Graduate Student Seminar*- Polynomial-time Approximation Algorithm for the Clique-Width of graphs