Cooperative Faculty Member
KURODA, Hirotoshi
 Position
 Specially Appointed Associate Professor
 Organization
 Program for Leading Graduate Schools Promotion Office, Faculty of Science
 Research Field
 Partial Differential equations
 Keywords
 variational problem, total variation, nonlinear semigroup theory, Mosco convergence
 Research Activities
 I am interested in partial differential equations which are relation to variational problems. So I especially study the gradient flow of the total variation that describes a process to remove a noise from the original image in the image processing. Since the total variation flow has a strong singularity, the subdifferential for convex functions and the nonlinear semigroup theory are useful to analyze its solvability and asymptotic behavior. These days I have an interest in the thin domain problems.
 Papers:

1.Y. Giga and H. Kuroda,
A counterexample to finite time stopping property for oneharmonic map flow,
Commun. Pure Appl. Anal., 14(2015), no.1, 121125.

2.Y. Giga, H. Kuroda and H. Matsuoka,
Fourthorder total variation flow with Dirichlet condition: Characterization of evolution and extinction time estimates,
Adv. Math. Sci. Appl., 24(2014), no.2, 499534.

3.H. Kuroda and N. Yamazaki,
Approximating problems of vectorial singular diffusion equations with inhomogeneous terms and numerical simulations,
Discrete Contin. Dyn. Syst. 2009, Dynamical Systems, Differential Equations and Applications. 7th AIMS Conference, Suppl., (2009), 486495.
 Personal webpage
 http://www7b.biglobe.ne.jp/~hkuroda/
YOSHIYASU, Toru
 Position
 Professional staff
 Organization
 Institute for the Advancement of Higher Education
 Research Field
 Symplectic Geometry
 Keywords
 hprinciple, Lagrangian submanifold
 Research Activities
 I am interested in flexibilities in Symplectic Geometry. I study the topology of Lagrangian submanifolds by using the theory of hprinciples. These days, I also have an interest in flexibility phenomena of limits in Symplectic Geometry.
 Papers:

1. T. Yoshiyasu, On Lagrangian embeddings into the complex projective
spaces, Internat. J. Math. 27 (2016), no. 5, 1650044, 12 pp.
 2. N. Kasuya and T. Yoshiyasu, On Lagrangian embeddings of
parallelizable manifolds, Internat. J. Math. 24 (2013), no. 9, 1350073,
9 pp.
 Personal webpage
 https://sites.google.com/site/toruyoshiyasu/
YORDANOV, Borislav
 Position
 Assistant Professor
 Organization
 Office of International Affairs
 Research Field
 Hyperbolic Partial Differential Equations
 Keywords
 Nonlinear wave equation, Diffusion Phenomenon, Nonlinear Damping
 Research Activities
 My research interests lie in the field of dissipative linear and nonlinear hyperbolic PDEs. The study of such equations has been inspired by theoretical physics. Indeed, hyperbolic equations arise in some of the fundamental
theories including general relativity, quantum field theory, electrodynamics, acoustics and elasticity.
My recent work concerns two problems: (1) global wellposedness for nonlinear wave equations with critical and supercritical damping and (2) asymptotic behavior for dissipative wave equations related to the socalled diffusion approximation of damped waves.
 Papers:

1. P. Radu, G. Todorova and B. Yordanov, The Generalized Diffusion Phenomenon and Applications, accepted in SIAM Journal of Math. Anal., 2015.

2. G. Todorova and B. Yordanov, On the Regularizing Effect of Nonlinear Damping in Hyperbolic Equations, Trans. Amer. Math. Soc., 367 (2015), 50435058.

3. R. Ikehata, G. Todorova and B. Yordanov, Diffusion Phenomenon for Strongly Damped Wave Equations, J. Diff. Equations 254 (2013), 33523368.