College of Education
University of the Ryukyus
Nishihara, Okinawa 903-0213, Japan
2 June 2025
NUS IMS
Singapore
I am a mathematician working on microlocal analysis and learning English, programming languages and applied harmonic analysis for upskilling.
Since 2020 I have been mainly studying microlocal analysis in integral geometry. The main objects are integral transforms such as geodesic X-ray transforms on Riemannian manifolds, double fibration transforms on manifolds, etc. The simplest examples of these integral transforms are the X-ray transform and the Radon transform on the Euclidean space, which are foundations of X-ray tomography and medical imaging.
Recently, I have been modernizing foundational mathematics courses such as calculus and linear algebra using computational thinking. My interactive notebooks, such as Julia & Pluto and Python & Jupyter Notebooks, are open on GitHub repositories and Google Colab, and I introduce my classes at international conferences and in academic journals on mathematics education and technology.
28 July - 1 August 2025,
Double fibration transforms with conjugate points,
MS-04 Integral geometry, rigidity and geometric inverse problems,
AIP 2025,
12th Applied Inverse Problems Conference,
FGV EMAp,
Rio de Janeiro,
abstract,
slides.
Joint work with Shubhan R. Jathar and Jesse Railo,
The matrix weighted real-analytic double fibration transforms,
submitted,
arXiv:2506.24067
, 22 pages.
The symbol of the normal operator for the d-plane transform on the Euclidean space,
submitted,
arXiv:2412.18197, 5 pages.
Geodesic X-ray transform and streaking artifacts on simple surfaces or on spaces of constant curvature,
submitted,
arXiv:2402.06899, 44 pages.
Microlocal analysis of double fibration transforms with conjugate points,
J. Geom. Anal., 36 (2026), ID 68, 22 pages,
doi.
Microlocal analysis of d-plane transform on the Euclidean space,
SIAM J. Math. Anal., 54(6) (2022), pp.6254-6287,
doi.
Bargmann transform on the space of hyperplanes,
J. Fourier Anal. Appl., 28 (2022), article No.72, 21 pages,
doi.
Inversion of higher dimensional Radon transforms of seismic-type,
Vietnam Journal of Mathematics,
49 (2021), pp.1185-1198,
doi.
Inversion of seismic-type Radon transforms on the plane,
Integral Transforms Spec. Funct., 31 (2020), pp.998-1009,
doi.
Joint work with Takashi Furuya and Takumi Koshikawa,
Hermite expansions of some tempered distributions,
J. Pseudo-Differ. Oper. Appl., 9 (2018), pp.105-124,
doi.
Holomorphic Hermite functions and ellipses,
Integral Transforms Spec. Funct. 28 (2017), pp.605-615,
doi.
Fourth-order dispersive systems on the one-dimensional torus,
J. Pseudo-Differ. Oper. Appl., 6 (2015), pp.237-263,
doi.
Joint work with Eiji Onodera,
A fourth-order dispersive flow into Kähler manifolds,
Z. Anal. Anwend., 34 (2015), pp.221-249,
doi.
Schrödinger flow into almost Hermitian manifolds,
Bull. Lond. Math. Soc.,
45 (2013), pp.37-51,
doi.
Joint work with Eiji Onodera,
A third order dispersive flow for closed curves into almost Hermitian manifolds,
J. Funct. Anal., 257 (2009), pp.388-404,
doi.
Bounded Berezin-Toeplitz operators on the Segal-Bargmann space,
Integral Equations Operator Theory, 63 (2009), pp.321-335,
doi.
Gain of analyticity for semilinear Schrödinger equations,
J. Differential Equations, 246 (2009), pp.681-723,
doi.
Resolvent estimates related with a class of dispersive equations,
J. Fourier Anal. Appl., 14 (2008), pp.301-325,
doi.
The initial value problem for a third order dispersive equation on the two dimensional torus,
Proc. Amer. Math. Soc., 133 (2005), pp.2083-2090,
doi.
The initial value problem for Schrödinger equations on the torus,
Int. Math. Res. Not., 2002:15 (2002), pp.789-820,
doi.
Gain of regularity for semilinear Schrödinger equations,
Math. Ann., 315 (1999), pp.529-567,
doi.
The initial value problem for the elliptic-hyperbolic Davey-Stewartson equation,
J. Math. Kyoto Univ., 39 (1999), pp.41-66,
doi.
The initial value problem for cubic semilinear Schrödinger equations,
Publ. Res. Inst. Math. Sci., 32 (1996), pp.445-471,
doi.
Global existence of small solutions to semilinear Schrödinger equations,
Comm. Partial Differential Equations, 21 (1996), pp.63-78,
doi.
Global existence of small solutions to semilinear Schrödinger equations with gauge invariance,
Publ. Res. Inst. Math. Sci., 31 (1995), pp.731-753,
doi.
Local existence for semilinear Schrödinger equations,
Math. Japon., 42 (1995), pp.35-52,
url.
Local existence for the semilinear Schrödinger equations in one space dimension,
J. Math. Kyoto Univ., 34 (1994), pp.353-367,
doi.
Hands-On Workshop:
schedule undecided,
Julia and Python on Google Colab,
handout,
GitHub, s
Google Colab.
Paper: Mathematics Education, in preparation.
Paper: Communication, submitted.
Paper: Educational Practice Report, submitted.
Paper: Educational Practice Report, submitted.
Contributed Talk:
13 - 16 December 2025,
Computational explorations in modern number theory: the Green–Tao theorem and the abc conjecture,
ATCM 2025,
The 30th Asian Technology Conference in Mathematics,
Ateneo de Manila University,
Manila,
html,
handout,
GitHub,
Google Colab.
Soojin Kim, Zheng Wei Chen, Jian Qi (Gerald) Tan, Assel Mussagulova,
A case study of the Singapore SkillsFuture Credit scheme: preliminary insights for making lifelong learning policy more effective,
Asian Journal of Political Science,
29 (2021), pp.192-214,
doi.
Millie Lee and Paul Morris,
Lifelong learning, income inequality and social mobility in Singapore,
International Journal of Lifelong Education,
35 (2016), pp.286-312,
doi.
Johnny Sung and Simon Freebody,
Lifelong learning in Singapore: where are we?,
Asia Pacific Journal of Education,
37 (2017), pp.615-628,
doi.
Charlene Tan,
Lifelong learning through the SkillsFuture movement in Singapore: challenges and prospects,
International Journal of Lifelong Education,
36 (2017), pp.278-291,
doi.
Ban Heng Choy,
Teacher education in Singapore: An insider view,
Journal für LehrerInnenbildung,
23(4) (2023), pp.66-77, Springer, Cham, 2015,
doi.
Berinderjeet Kaur et al,
Mathematics education in Singapore,
in Sung Je Cho eds,
The Proceedings of the 12th International Congress on Mathematical Education,
pp.311-316, Springer, Cham, 2015,
doi.
Tin Lam Toh,
A glimpse into the mathematics education research in Singapore,
Hiroshima Journal of Mathematics Education, 13 (2020), pp.99-120,
doi.
