九州大学 研究者情報
研究者情報 (研究者の方へ)入力に際してお困りですか?
基本情報 研究活動 教育活動 社会活動
櫻井 大督(さくらい だいすけ) データ更新日:2022.05.02



主な研究テーマ
計算幾何,トポロジー解析,可視化
キーワード:計算幾何,トポロジー解析,可視化
2019.05~2022.03.
従事しているプロジェクト研究
仮説のオントロジーに基づく可視化
2020.04~2023.03, 代表者:櫻井大督, 九州大学.
研究業績
主要原著論文
1. Shigeo Takahashi, Daisuke Sakurai, Miyuki Sasaki, Hiroko M. Miyamura, Yukihisa Sanada, Visual Analysis of Geospatial Multivariate Data for Investigating Radioactive Deposition Processes, The Visual Computer, 37, 12, 3039-3050, 2021.07.
2. Daisuke Sakurai, Osamu Saeki, Hamish Carr, Hsiang-Yun Wu, Takahiro Yamamoto, David Duke, Shigeo Takahashi, Interactive Visualization for Singular Fibers of Functions f: R3 → R2, IEEE Transactions on Visualization and Computer Graphics, https://doi.org/10.1109/TVCG.2015.2467433, 22, 1, 945-954, 2016.01, [URL], Scalar topology in the form of Morse theory has provided computational tools that analyze and visualize data from scientific and engineering tasks. Contracting isocontours to single points encapsulates variations in isocontour connectivity in the Reeb graph. For multivariate data, isocontours generalize to fibers - inverse images of points in the range, and this area is therefore known as fiber topology. However, fiber topology is less fully developed than Morse theory, and current efforts rely on manual visualizations. This paper presents how to accelerate and semi-automate this task through an interface for visualizing fiber singularities of multivariate functions R3 → R2. This interface exploits existing conventions of fiber topology, but also introduces a 3D view based on the extension of Reeb graphs to Reeb spaces. Using the Joint Contour Net, a quantized approximation of the Reeb space, this accelerates topological visualization and permits online perturbation to reduce or remove degeneracies in functions under study. Validation of the interface is performed by assessing whether the interface supports the mathematical workflow both of experts and of less experienced mathematicians..
3. Daisuke Sakurai, Kenji Ono, Hamish Carr, Jorji Nonaka, and Tomohiro Kawanabe, Flexible Fiber Surface : A Reeb-Free Approach, Topological Methods in Data Analysis and Visualization V, 2020.10, The fiber surface generalizes the popular isosurface to multi-fields, so that pre-images can be visualized as surfaces. As with the isosurface, however, the fiber surface suffers from visual occlusion. We propose to avoid such occlusion by restricting the components to only the relevant ones with a new component-wise flexing algorithm. The approach, flexible fiber surface, generalizes the manipulation idea found in the flexible isosurface for the fiber surface. The flexible isosurface in the original form, however, relies on the contour tree. For the fiber surface, this corresponds to the Reeb space, which is challenging for both the computation and user interaction. We thus take a Reeb-free approach, in which one does not compute the Reeb space. Under this constraint, we generalize a few selected interactions in the flexible isosurface and discuss the implication of the restriction..
4. Daisuke Sakurai, Takahiro Yamamoto, Visually Evaluating the Topological Equivalence of Bounded Bivariate Fields, Topological Methods in Visualization VI - Theory, Applications, and Software, 181-196, 2021.11, We apply visualization to evaluating a new topological equivalence rela-tion, which we call thetopologicalB+-equivalence. It has been used in our separate,yet ongoing, study in mathematics. The equivalence is a building block for thetopological study of maps of bounded manifolds into the plane (akabounded bivari-ate fields). In that study, we have introduced a few invariants that approximate theequivalence, which is hard to treat directly. In this chapter dedicated to the visual-ization community, we show that visualizing the Reeb space gives us a near-instantway of evaluating the invariants. The process has traditionally required an unpre-dictable amount of time due to manual analysis of high-order polynomials, whichwas necessary to obtain the invariant values. Our Reeb space visualization revealsthe topological information necessary for evaluating the invariants, and, doing so,the topologicalB+-equivalence itself. Previously, the visualization had been foundto serve as an introductory learning tool for studying examples of singular fibers.The present article goes further to demonstrate professional use cases..
5. Daisuke Sakurai and Takahiro Yamamoto, Investigating Topological Invariants in Bounded Bivariate Fields, Proceedings of TopoInVis 2019, 2019.06.
6. Tomohiro Kawanabe, Jorji Nonaka, Daisuke Sakurai, Kazuma Hatta, Shuhei Okayama and Kenji Ono, Showing Ultra-High-Resolution Images in VDA-Based Scalable Displays, Cooperative Design, Visualization, and Engineering: 16th International Conference, CDVE 2019, Mallorca, Spain, October 6–9, 2019, Proceedings, 2019.10.
主要総説, 論評, 解説, 書評, 報告書等
主要学会発表等
1. Shigeo Takahashi, Daisuke Sakurai, Miyuki Sasaki, Hiroko M. Miyamura, Yukihisa Sanada, Visual Analysis of Geospatial Multivariate Data for Investigating Radioactive Deposition Processes, Computer Graphics International 2021, 2021.09.
学会活動
学会大会・会議・シンポジウム等における役割
2020.04~2019.04.12, PacificVis 2020, Poster Co-chair.
その他の研究活動
海外渡航状況, 海外での教育研究歴
Laboratoire de Recherche en Informatique 6 (LIP6), Sorbonne University and French National Center for Scientific Research (UMR 7606 Sorbonne University - CNRS),, France, 2016.10~2017.04.
Zuse Institute Berlin, Germany, 2017.04~2019.04.
研究資金
科学研究費補助金の採択状況(文部科学省、日本学術振興会)
2020年度~2022年度, 若手研究, 代表, 仮説のオントロジーに基づく可視化.
競争的資金(受託研究を含む)の採択状況
2020年度~2020年度, 令和2年度IMI共同利用研究・研究集会II, 代表, Fiber Topology Meets Applications.

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