Portrait
Koichi Tanaka
Keio University
CV
About Me

I'm a master student at Keio University.

Curriculum Vitae
Education
  • Keio University
    Dept. of Electronics and Electrical Engineering
    Master Student
    Apr. 2025 - present
  • Keio University
    Dept. of Electronics and Electrical Engineering
    Apr. 2021 - Mar. 2025
Experience
  • Hanjuku-kaso, Co., Ltd.
    Research Intern
    May 2025 - present
  • LY Corporation
    Research Intern
    Aug. 2023 - present
  • CyberAgent AI Lab
    Research Intern
    Aug. 2023 - Aug. 2025
Selected Publications (view all )
Off-Policy Evaluation for Ranking Policies under Deterministic Logging Policies

Koichi Tanaka, Kazuki Kawamura, Takanori Muroi, Yusuke Narita, Yuki Sasamoto, Kei Tateno, Takuma Udagawa, WeiWei.du, Yuta Saito

In Proceedings of the Fourteenth International Conference on Learning Representations (ICLR) 2026 (Acceptance Rate=28%)

[OpenReview] [arXiv] [Code]

Off-Policy Evaluation for Ranking Policies under Deterministic Logging Policies

Koichi Tanaka, Kazuki Kawamura, Takanori Muroi, Yusuke Narita, Yuki Sasamoto, Kei Tateno, Takuma Udagawa, WeiWei.du, Yuta Saito

In Proceedings of the Fourteenth International Conference on Learning Representations (ICLR) 2026

[OpenReview] [arXiv] [Code]

Beyond Match Maximization and Fairness: Retention-Optimized Two-Sided Matching

Ren Kishimoto, Rikiya Takehi, Koichi Tanaka, Masahiro Nomura, Riku Togashi, Yoji Tomita, Yuta Saito

In Proceedings of the Fourteenth International Conference on Learning Representations (ICLR) 2026 (Acceptance Rate=28%)

[OpenReview] [arXiv] [Code]

Beyond Match Maximization and Fairness: Retention-Optimized Two-Sided Matching

Ren Kishimoto, Rikiya Takehi, Koichi Tanaka, Masahiro Nomura, Riku Togashi, Yoji Tomita, Yuta Saito

In Proceedings of the Fourteenth International Conference on Learning Representations (ICLR) 2026

[OpenReview] [arXiv] [Code]

Off-Policy Learning with Limited Supply

Koichi Tanaka*, Ren Kishimoto*, Bushun Kawagishi, Yusuke Narita, Yasuo Yamamoto, Nobuyuki Shimizu, Yuta Saito (* equal contribution)

In Proceedings of the ACM Web Conference 2026 (TheWebConf) 2026 (Acceptance Rate=20.1%)

[Proceedings] [arXiv] [Code]

Off-Policy Learning with Limited Supply

Koichi Tanaka*, Ren Kishimoto*, Bushun Kawagishi, Yusuke Narita, Yasuo Yamamoto, Nobuyuki Shimizu, Yuta Saito (* equal contribution)

In Proceedings of the ACM Web Conference 2026 (TheWebConf) 2026

[Proceedings] [arXiv] [Code]

Effective Off-Policy Evaluation and Learning in Contextual Combinatorial Bandits

Tatsuhiro Shimizu*, Koichi Tanaka*, Ren Kishimoto, Haruka Kiyohara, Masahiro Nomura, Yuta Saito (* equal contribution)

In Proceedings of the 18th ACM Conference on Recommender Systems (RecSys) 2024 Oral (Acceptance Rate=22%)

[Proceedings] [arXiv] [Code]

Effective Off-Policy Evaluation and Learning in Contextual Combinatorial Bandits

Tatsuhiro Shimizu*, Koichi Tanaka*, Ren Kishimoto, Haruka Kiyohara, Masahiro Nomura, Yuta Saito (* equal contribution)

In Proceedings of the 18th ACM Conference on Recommender Systems (RecSys) 2024 Oral

[Proceedings] [arXiv] [Code]

All publications