Combinatorics, q-series and special functions
(with Sangwook Kim and Seunghyun Seo) Refined enumeration of vertices among all rooted ordered d-trees, arXiv:1806.06417, Bulletin of the Korean Mathematical Society, 56(4), 899-910, 2019.
(with Jiang Zeng) Symmetric unimodal expansions of excedances in colored permutations, arXiv:1411.6184, European Journal of Combinatorics, 52, part A, 174-196, 2016. / MR3425973
(with Seunghyun Seo) Signed a-polynomials of graphs and Poincaré polynomials of real toric manifolds, arXiv:1212.6307, Bulletin of the Korean Mathematical Society, 52(2), 467-481, 2015. / MR3338206
(with Jang Soo Kim and Seunghyun Seo) Annular noncrossing permutations and minimal transitive factorizations, arXiv:1201.5703, Journal of Combinatorial Theory, Series A, 124, 251-262, 2014. / MR3176201
(with Sohyun Hwang et al) Context-dependent transcriptional regulations between signal transduction pathways, BMC Bioinformatics 2011, 12:19, 2011.
(with Jiang Zeng) A bijective enumeration of labeled trees with given indegree sequence, arXiv:0805.0067, Journal of Combinatorial Theory, Series A, 118(1), 115-128, 2011. / MR2737188
(with Jiang Zeng) The q-tangent and q-secant numbers via continued fractions, arXiv:0911.4658, European Journal of Combinatorics, 31(7), 1689-1705, 2010. / MR2673011
(with Seunghyun Seo) A generalized enumeration of labeled trees and reverse prüfer algorithm, arXiv:math/0601009, Journal of Combinatorial Theory, Series A, 114(7), 1357-1361, 2007. / MR2353128
(with Seunghyun Seo) On Delannoy paths without peaks and valleys, arXiv:2203.07770, preprint, 2022.
(with Suyoung Choi) On a decomposition of simple polytopes, in preparation, 2010.
A refined bijection between alternating permutations and 0-1-2 increasing trees, arXiv:1003.4564, preprint, 2010.
A new bijection between forests and parking functions, arXiv:0810.0427, preprint, 2008.
(Invited Talk) Symmetric unimodal expansions of Eulerian polynomials, 2019 KMS Spring Meeting, April 20, 2019, Kangwon National University, Chuncheon, Korea.
Convolutional Neural Networks in Keras with CIFAR-10 dataset, Optimization and Learning Tutorial 2018, Ajou University, Suwon, Korea, March 31, 2018.
Hot to use JupyterHub for mathematics, Math Colloquium, Inha University, Incheon, Korea, March 29, 2017.
Welcome to Python and SageMath, SageMath Developers Meeting 2017, Sungkyunkwan University, Korea, February 1, 2017
Hot to use JupyterHub for data analysis, Setup of JupyterHub and its application, Korea University, Korea, December 9, 2016.
Education and research by SageMath, Mathematical Software Working Seminar, Korea University, Seoul, Korea, June 12, 2015.
Continued fractions and generalized Fibonacci numbers, 2014 Combinatorics Workshop, Ajou University, Suwon, Korea, October 31, 2014.
Simsun permuations and Entringer families, Enumerative Combinatorics mini Workshop 2013, Ladena Condominium, Chuncheon, March 30, 2013.
(Poster) Minimal transitive factorizations of a permutation of type (p,q), FPSAC 2012, Nagoya, Japan, 2012.
Bijections for Entringer families, 9th Japan-Korea Workshop on Algebra and Combinatorics, Tohoku University, Sendai, Japan, January 25, 2011.
(Poster) A further correspondence between (bc,b)-parking functions and (bc,b)-forests, FPSAC 2009, Hagenberg, Austria, July 20-24, 2009.
Counting labelled trees with given indegree sequence, Journées du GDR Informatique Mathématique, Lyon, France, June 15-16, 2009.
Permutation patterns, ordered trees and continued fractions, 2002 KMS Spring Meeting, Hoseo University, Cheonan, Korea, April 27, 2002.
June - Nov. 2017 (6 months): Advanced distributed data analysis system and its applications, NIMS, Korea.
March 2017 - Feb. 2022 (5 years): Analysis of statistics for combinatorical objects using Multi-layer Neural Network, NRF, Korea.
Sep. - Dec. 2016 (3 months): Optimization of system for data analytics in industrial mathematics and its applications, NIMS, Korea.
May 2012 - April 2015 (3 years): Minimal transitive factorizations of a permutation, NRF, Korea.
Oct. 2008 - Sep. 2010 (2 years): Combinatorics of q-series and orthogonal polynomials, CNRS, France
Sep. 2007 - Sep. 2008 (1 year): The refined bijection between the combinatorial objects, Korea Research Foundation (KRF), Korea.