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Kihyuk (Ki) Hong | 홍기혁

Assistant Professor

Department of Industrial & Systems Engineering

KAIST (Korea Advanced Institute of Science & Technology)

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My primary area of research is artificial intelligence (AI) with a focus on reinforcement learning (RL). My main focus is on the design and analysis of computationally efficient algorithms with provable guarantees. I have worked on problems including non-stationary bandits, offline RL and constrained RL.

I was born and raised in South Korea. My alma maters are Johns Hopkins (BS, 2008), Stanford (MS, 2010) and University of Michigan (PhD, 2025. Advisor: Ambuj Tewari). Before starting my PhD, I worked on recommendation systems and search engines as a machine learning engineer at Meta (2010-2013) and Naver (2013-2018, 2019-2020).

Publications

[8] Marc Brooks*, Gabriel Durham*, Kihyuk Hong*, Ambuj Tewari. Generator-Mediated Bandits: Thompson Sampling for GenAI-Powered Adaptive Interventions. Preprint 2025. [paper]

[7] Kihyuk Hong, Ambuj Tewari. Offline Constrained Reinforcement Learning with Arbitrary Data Distributions under Partial Coverage. Preprint 2025. [paper]

[6] Kihyuk Hong, Ambuj Tewari. A Computationally Efficient Algorithm for Infinite-Horizon Average-Reward Linear MDPs. In Proceedings of the 42nd International Conference on Machine Learning, 2025*.* [paper]

[5] Kihyuk Hong, Woojin Chae, Yufan Zhang, Dabeen Lee, Ambuj Tewari. Reinforcement Learning for Infinite-Horizon Average-Reward Linear MDPs via Approximation by Discounted-Reward MDPs. In Proceedings of the 28th International Conference on Artificial Intelligence and Statistics, 2025. [paper]

[4] Woojin Chae, Kihyuk Hong, Yufan Zhang, Ambuj Tewari, Dabeen Lee. Learning Infinite-Horizon Average-Reward Linear Mixture MDPs of Bounded Span. In Proceedings of the 28th International Conference on Artificial Intelligence and Statistics, 2025. [paper]

[3] Kihyuk Hong, Ambuj Tewari. A Primal-Dual Algorithm for Offline Constrained Reinforcement Learning with Linear MDPs. In Proceedings of the 41st International Conference on Machine Learning, 2024*.* [paper]

[2] Kihyuk Hong, Yuhang Li, Ambuj Tewari. A Primal-Dual-Critic Algorithm for Offline Constrained Reinforcement Learning. In Proceedings of the 27th International Conference on Artificial Intelligence and Statistics, 2024. [paper]

[1] Kihyuk Hong, Yuhang Li, Ambuj Tewari. An Optimization-Based Algorithm for Non-Stationary Kernel Bandits without Prior Knowledge. In Proceedings of the 26th International Conference on Artificial Intelligence and Statistics, 2023. [paper]

Talks

  1. Invited talk, KAIST. ISE Department. May 2025.
  2. Invited talk, University of Washington. Computer Science Department. Apr 2025.
  3. Invited talk, Stanford University. Computer Science Department. Feb 2025.
  4. Statistics Department Seminar, University of Michigan. Dec 2024.
  5. Workshop Seminar. An algorithm for infinite-horizon average reward RL with linear MDPs. RL Theory Workshop. Jun 2024.
  6. Guest lecture. Introduction to reinforcement learning, guest lecture for STATS 503, University of Michigan. May 2023.