Research interests

• Stat&ML theory & methods on

  • Decision science - causal inference, multi-armed bandits, dynamic pricing

  • Multivariate data analysis - covariance matrices, precision matrices, clustering, fused lasso

• Application & collaborations on

  • e-commerce - 유저 피드백을 이용한 컨텐츠 추천 최적화 (멀티암 밴딧 기반), 동적 가격결정, 실시간 입찰

  • Healthcare - 보건의료 빅데이터(건강보험심사평가원/건강보험공단) 기반 (1) 질병요인 탐색 및 (2) 임상적 의사결정 보조

  • Manufacturing - 센서 데이터 기반 예지정비

Submitted / In Preparation

(†equal contribution, *corresponding author,  #: under my supervision)

• Semi-parametric contextual pricing algorithm using Cox proportional hazards model: Upper and lower bounds

• Semi-parametric contextual combinatorial bandits (with Yunseo Choi)

• Non-stationary and semi-parametric contextual bandits (with Jaesung Hwang and Gi-Soo Kim)

• Association of body mass index and waist circumference with health outcomes among patients with Type-II diabetes mellitus (with Eunkyoung Lee# and Hyun Joon Shin)

• Estimating optimal individualized treatment rules from heterogeneous data sources  (with Ying-Qi Zhao)

• Causal inference for treatment and unlabeled groups

Peer-reviewed Papers

(†equal contribution, *corresponding author, #: under my supervision)

Theory & Methods

• [23] Young-Geun Choi, Gi-Soo Kim*, Seunghoon Paik and Myunghee Cho Paik*  (2023). Semi-Parametric Contextual Bandits with Graph-Laplacian Regularization. Information Sciences, 645, 119367. Link

• [21] Young-Geun Choi†, Soohyun Ahn† and Jayoun Kim* (2023). Model-based clustering for mixed data with sparse dependency structure. IEEE Access, 11:75945-75954. Link

• [20] Young-Geun Choi, Gi-Soo Kim, Yunseo Choi#, Woo Sung Cho, Myunghee Cho Paik, and Min-Hwan Oh* (2023). Semi-parametric contextual pricing algorithm using Cox proportional hazards model. The Proceedings of the 40th International Conference on Machine Learning (ICML), PMLR 202:5771-5786, 2023. Link

• [18] Muxuan Liang, Young-Geun Choi, Yang Ning, Marueen Smith, and Ying-Qi Zhao* (2022). Estimation and inference on high-dimensional individualized treatment rule in observational data using split-and-pooled de-correlated score. Journal of Machine Learning Research, 23(262), 1-6. Link

• [13] Young-Geun Choi, Seunghwan Lee, and Donghyeon Yu* (2022).  An efficient parallel block coordinate descent algorithm for large-scale precision matrix estimation using graphics processing units. Computational Statistics, 37(1), 419-443. Link 

• [12] Young-Geun Choi, Larry Hanrahan, Derek Norton, and & Ying-Qi Zhao* (2022). Simultaneous disease mapping and hot spot detection with application to childhood obesity surveillance from electronic health records. Biometrics, 78(1), 324-336. Link

• [9] Seonghun Cho†, Young-Geun Choi†, Johan Lim, Won Jun Lee, Hyun-Jeong Bai, and Sungwon Kwon (2021). Test for uniformity of exchangeable random variables on the circle. Journal of the Korean Statistical Society, 50, 615–630.  (*: equal contribution) Link 

• [8] Seonghun Cho, Young-Geun Choi,  Shota Katayama, and Johan Lim* (2021). Fixed support positive definite modification of covariance matrix by minimizing matrix L-infinity norm with applications to portfolio optimization. AStA Advances in Statistical Analysis 105, 601–627. Link 

• [7] Young-Geun Choi, Anindya Roy, Junyong Park, and Johan Lim* (2019). Fixed support positive-definite modification of covariance matrix estimators via linear shrinkage. Journal of Multivariate Analysis, 171, 234-249. Link

• [6] Young-Geun Choi, Wei-Yann Tsai, & Myunghee Cho Paik* (2019). Generalized class of test statistic for testing quasi-independence in left-truncated and right-censored data. Statistica Sinica, 29(2), 789-808. Link 

• [5] Young-Geun Choi, Johan Lim* and Sujung Choi (2019). High-dimensional Markowitz portfolio optimization problem: Empirical comparison of covariance matrix estimators. Journal of Statistical Computation and Simulation, 89(7), 1278-1300. Link 

• [4] Yongchan Kwon, Young-Geun Choi, Taesung Park, Andreas Ziegler, & Myunghee Cho Paik* (2017). Generalized estimating equations with stabilized working correlation structure. Computational Statistics & Data Analysis, 106, 1–11. Link 

• [3] Young-Geun Choi, Chi Tim Ng, and Johan Lim* (2017). Regularized LRT for large scale covariance matrices: One sample problem. Journal of Statistical Planning and Inference, 180, 108–123. Link 

Applied & Collaborative

• [22] Jeeyeon Lee, Andrew Won Jun Yang, Liam Il-Young Chung, Jisang Yu, Yunjoo Lee, Hye Sung Kim, Hyun Joon Shin, Young-Geun Choi, Ankit Bharat, and Young Kwang Chae* (2023). A Comprehensive Landscape of De Novo Malignancy After Double Lung Transplantation. Transplant International, 36:11552. Link

• [19] Yo Han Lee, Hyun-Hee Heo, Hyerim Noh#, Deok Hyun Jang, Young-Geun Choi*, Won Mo Jang*, and Jin Yong Lee (2023). Patterns and trends in factors associated with affective and cognitive risk perceptions of COVID-19. PLoS ONE, 18(6), e0280779. Link

• [17] Jungyoon Ohn, Young-Geun Choi, Jieun Yun, Seong Jin Cho* (2022). Identifying patients with deteriorating generalized pustular psoriasis: Development of a prediction model. The Journal of Dermatology, 49(7), 675-681. Link 

• [16] Hyerim Noh†#, Jongseong Lee†, Ronald Chow†, Jihui Lee, Charles B. Simone II, Hyun Joon Shin, and Young-Geun Choi* (2022).  The prognostic role of anticoagulants in COVID-19 patients: National COVID-19 cohort in South Korea. Annals of Palliative Medicine, 11(4), 1317-1325. Link

• [15] Hyun Joon Shin†, Ronald Chow†, Hyerim Noh†#, Jongseong Lee, Jihui Lee, Charles B. Simone II, and Young-Geun Choi* (2022).  The association between immunosuppressants use and COVID-19 adverse outcomes: National COVID-19 cohort in South Korea. Annals of Palliative Medicine, 11(4), 1308-1316. Link

• [14] Ronald Chow†, Jihui Lee†, Hyerim Noh†#, Jongseong Lee, Charles B. Simone II, Hyun Joon Shin*, and Young-Geun Choi* (2022).  The association between statin and Covid-19 adverse outcome: National COVID-19 cohort in South Korea. Annals of Palliative Medicine, 11(4), 1294-1307.  Link

• [11] Leonard Chiu†, Chun-Han Lo, Max Shen, Nicholas Chiu, Rahul Aggarwal, Jihui Lee, Young-Geun Choi, Henry Lam, Elizabeth Horn Prsic, Ronald Chow*, Hyun Joon Shin*  (2021). Colchicine use in patients with COVID-19: A systematic review and meta-analysis, PLoS ONE, 16(12): e0261358.  Link  

• [10] Ronald Chow, James Im, Nicholas Chiu, Leonard Chiu, Rahul Aggarwal, Jihui Lee, Young-Geun Choi, Elizabeth Horn Prsic, and Hyun Joon Shin* (2021).  The protective association between statins use and adverse outcomes among COVID-19 patients: A systematic review and meta-analysis, PLoS ONE, 16(6): e0253576.  Link  

• [2] Huy Truong Nguyen, Dong-Kyu Lee, Young-Geun Choi et al. (2016). A 1H NMR-based metabolomics approach to evaluate the geographical authenticity of herbal medicine and its application in building a model effectively assessing the mixing proportion of intentional admixtures: A case study of Panax ginseng. Journal of Pharmaceutical and Biomedical Analysis, 124, 120–128. Link

• [1] Jung A Um, Young-Geun Choi, Dong-Kyu Lee,  et al. (2013). Discrimination between genetically identical peony roots from different regions of origin based on 1H-nuclear magnetic resonance spectroscopy-based metabolomics: determination of the geographical origins and estimation of the mixing proportions of blended. Analytical and Bioanalytical Chemistry, 405(23), 7523–34. Link

Domestic journals

• Young-Geun Choi and Donghyeon Yu (2019). Causal inference from nonrandomized data: Key concepts and recent trends. Korean Journal of Applied Statistics. 32(2), 173–185. Link

Patents

• Young-Geun Choi, Taehoon Lee, Junghyun Namkung, and Philghyun Kang. (2019). Method and Apparatus for Cyclic Time Series Data Feature Extraction. Application number 10-2019-0027851 (KR).