Choi, Sunmook / 최선묵
I am a third-year PhD student in Center for Applied Mathematics (CAM) at Cornell University, under the supervision of Professor Sarah Dean.
I study bandits, reinforcement learning, optimal control using tools and concepts from statistical learning theory, optimization, and control theory. My current research is mainly focused on bandit problems, optimal control problems, and recommender systems, using the following mathematical modeling (linear dynamics with bilinear observations):
\[\begin{aligned} x_{t+1} &= Ax_t + Bu_t + w_t \\ y_t &= u_t^\top C x_t + z_t \end{aligned}\]I received my M.S. in Mathematics in 2024 and my B.S. in Mathematics in 2022, both from Korea University (KU). At KU, I’d had the pleasure of working with Professor Seungsang Oh in DLmath Lab. I had mainly worked on deep learning in audio domain, such as model architecture designing for audio spoofing detection, automatic speaker verification, etc.
Publications
The most up to date list of my papers is available in Google Scholar.
Selected Publications
Cornell University
- Two-Layer Linear Auto-Regressive Models Estimate Latent States (Yahya Sattar, Sunmook Choi, Leo Maynard-Zhang, Yassir Jedra, Maryam Fazel, Sarah Dean) ICML 2026
- Explore-then-Commit for Nonstationary Linear Bandits with Latent Dynamics (Sunmook Choi, Yahya Sattar, Yassir Jedra, Maryam Fazel, Sarah Dean) AISTATS 2026
- Dual Control of Linear Systems from Bilinear Observations with Belief Space Model Predictive Control (Daniel Cao, Beixi Du, Andrew Lowitt, Sunmook Choi, Sarah Dean, Yahya Sattar) arXiv
- Sub-optimality of the Separation Principle for Quadratic Control from Bilinear Observations (Yahya Sattar, Sunmook Choi, Yassir Jedra, Maryam Fazel, Sarah Dean) CDC 2025
Korea University
- TB-ResNet: Bridging the gap from TDNN to ResNet in automatic speaker verification with temporal-bottleneck enhancement (Sunmook Choi, Sanghyeok Chung, Seungeun Lee, Soyul Han, Taein Kang, Jaejin Seo, Il-Youp Kwak, Seungsang Oh) ICASSP 2024
- Augmented Aztec bipyramid and dicube tilings (Sunmook Choi, Sangyop Lee, Seungsang Oh) Discrete Mathematics 2024 (Editor’s Choice)
- Low-quality fake audio detection through frequency feature masking (Il-Youp Kwak, Sunmook Choi, Jonghoon Yang, Yerin Lee, Soyul Han, Seungsang Oh) The 1st International workshop on deepfake detection for audio multimedia, ACM 2022
- Overlapped Frequency-Distributed Network: Frequency-Aware Voice Spoofing Countermeasure (Sunmook Choi, Il-Youp Kwak, Seungsang Oh) Interspeech 2022
- Light-weight frequency information aware neural network architecture for voice spoffing detection (Sunmook Choi, Jonghoon Yang, Yerin Lee, Seungsang Oh, Il-Youp Kwak) ICPR 2022
Teaching
In previous semesters, I was a teaching assistant of MATH2940: Linear Algebra for Engineers in (Fall 2024, Spring 2025, Fall 2025) and MATH4310: Linear Algebra in Spring 2026. At KU, I was a TA in MATH221: Linear Algebra I in (Spring 2022, Spring 2023) and MATH222: Linear Algebra II in (Fall 2022, Fall 2023).
News
- 07/2026: Served as a reviewer for NeurIPS 2027.
- 07/2026: Attended ICML in Seoul, Korea! Presented a poster of the paper.
- 05/2026: Designated as a Gold Reviewer (top 25% of the reviewers) from ICML 2026! Thanks for the area chairs, and see you all there!
- 05/2026: Served as a reviewer for TMLR.
- 05/2026: Attended AISTATS in Tanger, Morocco! Presented a poster.
- 04/2026: Our paper got accepted to ICML 2026! (with Y. Sattar, L. Maynard-Zhang, Y. Jedra, M. Fazel, S. Dean)
- 04/2026: A paper is now available in arXiv! (paper link)
- 03/2026: Served as a reviewer for ICML 2026.
- 01/2026: Accepted to AISTATS 2026! (paper link)
- 12/2025: Attended CDC 2025 in Rio, Brazil! Presented a 15-minute talk about this paper.
- 05/2025: Attended NESCW 2025 in Columbia University! Presented a poster about this paper.