Updated on 2026/10/02

写真a

 
HIKIMA YUYA
 
Organization
School of Engineering Assistant Professor
Title
Assistant Professor
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Research Interests

  • 確率的最適化

  • 非凸最適化

  • 機械学習

  • オペレーションズ・リサーチ

  • 価格最適化

  • 数理最適化

Research Areas

  • Informatics / Computational science

  • Informatics / Theory of informatics

  • Informatics / Mathematical informatics

Education

  • The University of Tokyo   The Graduate School of Information Science and Technology   Department of Mathematical Informatics

    2022.4 - 2026.3

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    Country: Japan

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  • Kyoto University   Graduate School of Informatics   Department of Applied Mathematics and Physis

    2016.4 - 2018.3

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    Country: Japan

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  • Kyoto University   Faculty of Economics   Department of Economics and Business

    2012.4 - 2016.3

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    Country: Japan

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Research History

  • Institute of Science Tokyo   Assistant Professor

    2026.4

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  • NTT株式会社   コミュニケーション科学基礎研究所

    2023.4 - 2026.3

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  • NTT株式会社   サービスイノベーション総合研究所

    2018.4 - 2023.3

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Professional Memberships

  • 日本オペレーションズ・リサーチ学会

    2016

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Papers

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MISC

  • Adaptive Gradient-Based Methods for a Broader Class of Optimization Problems under Performative Prediction

    Hiroki Hamaguchi, Yuya Hikima, Hiroshi Sawada, Akiko Takeda

    2026.7

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    We study optimization under performative prediction, where deploying a model affects the future data distribution. For this setting, several gradient-based approaches have been proposed. However, they typically assume specific data distributions or loss functions, which limit their practical applicability. To overcome these limitations, we propose a gradient-based optimization method with convergence guarantees under substantially weaker assumptions. Our method explicitly estimates the induced distribution shift through finite differences. It enables higher-dimensional optimization across broader classes of loss functions and data distributions. We also propose a practical variant that reduces the number of samples required. Numerical experiments demonstrate that our proposed algorithms converge faster and more consistently than existing ones.

    arXiv

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    Other Link: https://arxiv.org/pdf/2607.26562v1

  • Joint Pricing and Matching for Resource Allocation Platforms via Min-cost Flow Problem

    Yuya Hikima, Yasunori Akagi, Hideaki Kim

    2024.4

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    Stochastic matching is the stochastic version of the well-known matching problem, which consists in maximizing the rewards of a matching under a set of probability distributions associated with the nodes and edges. In most stochastic matching problems, the probability distributions inherent in the nodes and edges are set a priori and are not controllable. However, many resource allocation platforms can control the probability distributions by changing prices. For example, a rideshare platform can control the distribution of the number of requesters by setting the fare to maximize the reward of a taxi-requester matching. Although several methods for optimizing price have been developed, optimizations in consideration of the matching problem are still in its infancy. In this paper, we tackle the problem of optimizing price in the consideration of the resulting bipartite graph matching, given the effect of the price on the probabilistic uncertainty in the graph. Even though our problem involves hard to evaluate objective values and is non-convex, we construct a (1-1/e)-approximation algorithm under the assumption that a convex min-cost flow problem can be solved exactly.

    arXiv

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    Other Link: https://arxiv.org/pdf/2404.19241v1

Presentations

  • 制御可能な不確実性を含むマッチング問題の最適化 Invited

    引間 友也

    離散最適化ワークショップ  2023.2 

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    Presentation type:Oral presentation (invited, special)  

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Awards

  • 未来を担う若手研究者の集い 2025 優秀発表賞

    2025.6   日本OR学会研究部会:最適化の理論とアルゴリズム   決定変数依存型不確実性を考慮した非凸最適化問題に対する0次法

    引間友也

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  • 未来を担う若手研究者の集い 2024 優秀発表賞

    2024.5   日本OR学会研究部会:最適化の理論とアルゴリズム   決定変数に依存する不確実性を含む価格最適化問題に対する確率的射影勾配降下法

    引間 友也

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  • 山下記念研究賞

    2020.7   情報処理学会   交通経済学に基づく人の時間価値を考慮したタクシー配車戦略の最適化

    引間 友也

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  • 若手研究発表会2017年度 優秀発表賞

    2017.10   日本オペレーションズ・リサーチ学会関西支部   基底追跡ノイズ除去に対する有効制約法

    引間 友也,山下 信雄

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  • Excellent Student Presentation in the 61st Annual Conference of the Institute of Systems

    2017.5   The Institute of Systems, Control and Information Engineers  

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  • 若手研究発表会2016年度 優秀発表賞

    2016.10   日本オペレーションズ・リサーチ学会関西支部   L1正則化問題に対する有効制約法

    引間 友也, 山下 信雄

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Teaching Experience

  • Data Analysis for Industrial Engineering and Economics

    2026.4 Institution:Institute of Science Tokyo

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  • Reading in Industrial Engineering and Economics

    2026.4 Institution:Institute of Science Tokyo

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