KOYAMADA Sotetsu

Graduate School of Economics / Division of EconomicsAssociate Professor
Faculty of Economics / Department of Economics

Research Keyword

  • Reinforcement Learning

Paper

  • Emergence of Exploration in Policy Gradient Reinforcement Learning via Retrying
    Soichiro Nishimori, Paavo Parmas, Sotetsu Koyamada, Tadashi Kozuno, Toshinori Kitamura, Shin Ishii, Yutaka Matsuo
    2026, International Conference on Machine Learning (ICML)
    [Refereed]

  • Haruka Kita, Sotetsu Koyamada, Yotaro Yamaguchi, Shin Ishii
    IEEE, 2024, IEEE Conference on Games (CoG), 1 - 4
    [Refereed]
    International conference proceedings

  • A Batch Sequential Halving Algorithm without Performance Degradation.
    Sotetsu Koyamada, Soichiro Nishimori, Shin Ishii
    2024, Reinforcement Learning Journal (RLJ), 5, 2218 - 2232
    [Refereed]
    Scientific journal

  • Soichiro Nishimori, Sotetsu Koyamada, Shin Ishii
    2023, arXiv, 2304.09769
    Scientific journal

  • Pgx: Hardware-Accelerated Parallel Game Simulators for Reinforcement Learning.
    Sotetsu Koyamada, Shinri Okano, Soichiro Nishimori, Yu Murata, Keigo Habara, Haruka Kita, Shin Ishii
    2023, Advances in Neural Information Processing Systems (NeurIPS)
    [Refereed]
    International conference proceedings

  • Sotetsu Koyamada, Keigo Habara, Nao Goto, Shinri Okano, Soichiro Nishimori, Shin Ishii
    IEEE, 2022, IEEE Conference on Games (CoG), 504 - 507
    [Refereed]
    International conference proceedings

  • Suphx: Mastering Mahjong with Deep Reinforcement Learning.
    Junjie Li, Sotetsu Koyamada, Qiwei Ye, Guoqing Liu, Chao Wang, Ruihan Yang, Li Zhao, Tao Qin, Tie-Yan Liu, Hsiao-Wuen Hon
    2020, arXiv, 2003.13590
    Scientific journal

  • Neural Sequence Model Training via $α$-divergence Minimization.
    Sotetsu Koyamada, Yuta Kikuchi, Atsunori Kanemura, Shin-ichi Maeda, Shin Ishii
    2017, ICML Workshop on Learning to Generate Natural Language (LGNL)
    [Refereed]
    Scientific journal

  • Deep learning of fMRI big data: a novel approach to subject-transfer decoding.
    Sotetsu Koyamada, Yumi Shikauchi, Ken Nakae, Masanori Koyama, Shin Ishii
    2015, arXiv, 1502.00093
    Scientific journal

  • Sotetsu Koyamada, Masanori Koyama, Ken Nakae, Shin Ishii
    Springer, 2015, Pacific-Asia Conference on Knowledge Discovery and Data Mining (PAKDD), 621 - 632
    [Refereed]
    International conference proceedings

  • Construction of Subject-independent Brain Decoders for Human fMRI with Deep Learning
    Sotetsu Koyamada, Yumi Shikauchi, Ken Nakae, Shin Ishii
    2014, Proceedings of the International Conference on Data Mining, Internet Computing, and Big Data
    [Refereed]

MISC

  • 「自ら学ぶAI」 の原点
    小山田創哲, 石井 信
    Nov. 2025, 岩波書店「科学」

Books And Other Publications

  • 速習強化学習 : 基礎理論とアルゴリズム
    Szepesvári, Csaba, 小山田, 創哲, 前田, 新一, 小山, 雅典
    共立出版, Sep. 2017, Japanese, ISBN: 9784320124226

Lectures, oral presentations, etc.

  • A Batch Sequential Halving Algorithm without Performance Degradation
    Reinforcement Learning Conference, 2024

  • Pgx: Hardware-Accelerated Parallel Game Simulators for Reinforcement Learning
    Advances in Neural Information Processing Systems (NeurIPS), 2023

  • Mjx: A framework for Mahjong AI research
    IEEE Conference on Games, 2022

  • Neural Sequence Model Training via α-divergence Minimization
    ICML Workshop on Learning to Generate Natural Language (LGNL), 2017

  • Principal Sensitivity Analysis
    Pacific-Asia Conference on Knowledge Discovery and Data Mining (PAKDD), May 2015

  • Knowledge Discovery for Nonlinear Classifier in Functional Neuroimaging
    SNSS2015, Mar. 2015

  • Knowledge Discovery for Nonlinear Classifier in Functional Neuroimaging
    AEARU Workshop on Computer Science and Web Technology, Feb. 2015
    Poster presentation

  • Principal Sensitivity Analysis
    Machine Learning Summer School'15, 2015

  • Construction of Subject-independent Brain Decoders for Human fMRI with Deep Learning
    International Conference on Data Mining, Internet Computing, and Big Data, Nov. 2014

  • Learning the subject-independent discriminative features from the large-scale fMRI database
    Neuro2014, Sep. 2014

  • 大規模fMRIデータベースからの脳活動表現の学習
    脳と心のメカニズム 第14回冬のワークショップ, Jan. 2014

Affiliated Academic Society

  • ACM
    2025 - Present

Research Themes

  • GPUネイティブプランニングアルゴリズムの開発
    小山田 創哲
    日本学術振興会, 科学研究費助成事業, 若手研究, 神戸大学, 01 Apr. 2026 - 31 Mar. 2029