Updated on 2026/01/25

写真a

 
OKAZAKI FUMIYA
 
Organization
School of Computing Assistant Professor
Title
Assistant Professor
Contact information
メールアドレス
External link

Degree

  • Doctor of Science ( 2024.3   Tohoku University )

Research Interests

  • Topology optimization

  • Stochastic Analysis

Research Areas

  • Natural Science / Applied mathematics and statistics

  • Natural Science / Basic analysis

Education

  • Tohoku University   Graduate School of Science   Department of Mathematics

    2021.4 - 2024.3

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    Notes: Doctoral course

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Research History

  • Institute of Science Tokyo   School of Computing   Assistant Professor

    2025.8

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  • The University of Tokyo   The Graduate School of Engineering Department of Mechanical Engineering   Project Researcher

    2024.4 - 2025.7

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  • Japan Society for the Promotion of Science Research Fellowships for Young Scientists DC2

    2022.4 - 2024.3

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Professional Memberships

  • The Mathematical Society of Japan

    2024.4

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Papers

  • Topology optimization concerning the mass distribution via filtered gradient flows on the Wasserstein space

    Fumiya Okazaki, Takayuki Yamada

    2026.1

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    Authorship:Lead author  

    In this article, we formulate topology optimization problems concerning the mass distribution as minimization problems for functionals on the Wasserstein space. We relax optimization problems regarding non-convex objective functions on the Wasserstein space by using the Neumann heat semigroup and prove the existence of minimizers of relaxed problems. Furthermore, we introduce the filtered Wasserstein gradient flow and derive the error estimate between the original Wasserstein gradient flow and the filtered one in terms of the Wasserstein distance. We also construct a candidate for the optimal mass distribution for a given fixed total mass and simultaneously obtain the shape of the material by the numerical calculation of filtered Wasserstein gradient flows.

    arXiv

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    Other Link: https://arxiv.org/pdf/2601.14332v1

  • On sensitivities regarding shape and topology optimization as derivatives on Wasserstein spaces Reviewed

    Fumiya Okazaki, Takayuki Yamada

    to appear in Tohoku Series of Mathematical Science, Springer   2026

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    Authorship:Lead author  

    In this paper, we apply the framework of optimal transport to the formulation
    of optimal design problems. By considering the Wasserstein space as a set of
    design variables, we associate each probability measure with a shape
    configuration of a material in some ways. In particular, we focus on
    connections between differentials on the Wasserstein space and sensitivities in
    the standard setting of shape and topology optimization in order to regard the
    optimization procedure of those problems as gradient flows on the Wasserstein
    space.

    arXiv

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    Other Link: http://arxiv.org/pdf/2411.12234v1

  • Horizontal $Δ$-semimartingales on orthonormal frame bundles Reviewed

    Fumiya Okazaki

    Osaka Journal of Mathematics (in press)   2025

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    In this article, we deal with stochastic horizontal lifts and
    anti-developments of semimartingales with jumps on complete and connected
    Riemannian manifolds without any assumption for their curvatures. We prove two
    one-to-one correspondences among some classes of discontinuous semimartingales
    on Riemannian manifolds, orthonormal frame bundles and Euclidean spaces by
    using the stochastic differential geometry with jumps introduced by Cohen
    (1996). Both of these two results are extension of the one shown in
    Pontier-Estrade (1992). The first result is the correspondence in the case
    where jumps of semimartingales are regarded as initial velocities of geodesics
    which are not necessarily minimal. In the second result, we also established
    the correspondence in the situation where jumps of semimartingales are given by
    connection rules, but we impose the condition that the jumps of semimartingales
    are small. The latter result enables us to construct martingales for a given
    connection rule with small jumps on any compact manifold from local martingales
    on a Euclidean space through horizontal semimartingales on orthonormal
    semimartingales.

    arXiv

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    Other Link: http://arxiv.org/pdf/2105.04824v2

  • On sequences of martingales with jumps on Riemannian submanifolds

    Fumiya Okazaki

    arXiv:2409.17118   2024.9

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  • Probabilistic Characterization of Weakly Harmonic Maps with Respect to Non-Local Dirichlet Forms Reviewed

    Fumiya Okazaki

    Potential Analysis   62 ( 1 )   1 - 25   2024.3

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    Abstract

    We characterize weakly harmonic maps with respect to non-local Dirichlet forms by Markov processes and martingales. In particular, we can obtain discontinuous martingales on Riemannian manifolds from the image of symmetric stable processes under fractional harmonic maps in a weak sense. Based on this characterization, we also consider the continuity of weakly harmonic maps along the paths of Markov processes and describe the condition for the continuity of harmonic maps by quadratic variations of martingales in some situations containing cases of energy minimizing maps.

    DOI: 10.1007/s11118-024-10129-5

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    Other Link: https://link.springer.com/article/10.1007/s11118-024-10129-5/fulltext.html

  • Convergence of Martingales with Jumps on Submanifolds of Euclidean Spaces and its Applications to Harmonic Maps Reviewed

    Fumiya Okazaki

    Journal of Theoretical Probability   37 ( 2 )   1168 - 1198   2023.7

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    Publishing type:Research paper (scientific journal)   Publisher:Springer Science and Business Media LLC  

    DOI: 10.1007/s10959-023-01273-6

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    Other Link: https://link.springer.com/article/10.1007/s10959-023-01273-6/fulltext.html

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Awards

  • 博士論文川井賞

    2024.3   公益財団法人 川井数理科学財団  

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  • 川井数学奨励賞

    2018.3   公益財団法人 川井数理科学財団  

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Research Projects

  • リーマン計量の摂動に付随する多様体上の確率過程の族及び調和写像の研究

    Grant number:25K17264  2025.4 - 2029.3

    日本学術振興会  科学研究費助成事業  若手研究

    岡嵜 郁也

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    Grant amount:\4810000 ( Direct Cost: \3700000 、 Indirect Cost:\1110000 )

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  • 不連続な確率ヤコビ場の構成とそれを用いた調和写像の解析

    Grant number:24K22827  2024.7 - 2026.3

    日本学術振興会  科学研究費助成事業  研究活動スタート支援

    岡嵜 郁也

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    Grant amount:\2860000 ( Direct Cost: \2200000 、 Indirect Cost:\660000 )

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  • α/2-調和写像から定まる部分多様体上の不連続なマルチンゲールに関する研究

    Grant number:22KJ0237  2023.3 - 2024.3

    日本学術振興会  科学研究費助成事業  特別研究員奨励費

    岡嵜 郁也

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    Grant amount:\1700000 ( Direct Cost: \1700000 )

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Teaching Experience

  • Forum on Computing

    2025.9 - 2026.3 Institution:Institute of Science Tokyo

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  • Calculus II (Exercises)

    2022.4 - 2023.3 Institution:Sendai National College of Technology

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