## Basic Information

### Major Professional Backgrounds

- 1992/04/01, 1996/03/31, Tokyo National College of Technology, Lecturer
- 1996/04/01, 1998/03/31, Hiroshima University, Faculty of School Education, Lecturer

### Academic Degrees

- Doctor of Science, Tokyo University of Science
- Master of Science, Tokyo University of Science

### Research Fields

- Mathematical and physical sciences;Mathematics;Mathematical analysis

### Research Keywords

- wave equation
- Asymptotic profile, Energy decay
- Exterior problem, Cauchy problem
- Fourier Analysis, Real Analysis, Functional Analysis

### Affiliated Academic Societies

- Mathematical Society of Japan, 1988/10

## Educational Activity

### Course in Charge

- 2021, Liberal Arts Education Program1, 1Term, CalculusI
- 2021, Undergraduate Education, 2Term, Introduction to Analysis
- 2021, Undergraduate Education, 4Term, Practics in Introduction to Algebra
- 2021, Undergraduate Education, 4Term, Research Methods in Analysis II
- 2021, Undergraduate Education, 4Term, Study of Instructional Materials in Analysis
- 2021, Undergraduate Education, Second Semester, Graduation Thesis
- 2021, Undergraduate Education, First Semester, Study of Instructional Materials in Analysis Education
- 2021, Undergraduate Education, Second Semester, Practical Seminar for the Teaching Profession
- 2021, Graduate Education (Doctoral Program) , 1Term, Research into Curriculum and Instruction Sciences (Specialization in Mathematics Education)
- 2021, Graduate Education (Doctoral Program) , 3Term, Research into Curriculum and Instruction Sciences (Specialization in Mathematics Education)
- 2021, Graduate Education (Master's Program) , First Semester, Special Study in Mathematics Education A
- 2021, Graduate Education (Master's Program) , Second Semester, Special Study in Mathematics Education A
- 2021, Graduate Education (Master's Program) , 2Term, Basic Course in Teaching Material Design for Science and Culture (Mathematics) a
- 2021, Graduate Education (Doctoral Program) , First Semester, Special Study
- 2021, Graduate Education (Doctoral Program) , Second Semester, Special Study

## Research Activities

### Academic Papers

- ★, Asymptotic profile and optimal decay of solutions of some wave equations with logarithmic damping, Z. Angew. Math. Physics, 71:148, 2020, August, 27
- ★, ENERGY DECAY ESTIMATES FOR WAVE EQUATIONS WITH A FRACTIONAL DAMPING, DIFFERENTIAL AND INTEGRAL EQUATIONS, 25(9-10), 939-956, 2012
- ★, Optimal decay rate of the energy for wave equations with critical potential, JOURNAL OF THE MATHEMATICAL SOCIETY OF JAPAN, 65(1), 183-236, 201301
- On the existence of global solutions for some nonlinear hyperbolic equations with Neumann conditions, TRU Mathematics, 24, 1-17, 19880401
- Yosida approximation and nonlinear hyperbolic equation (with N.Okazawa), Nonlinear Analysis TMA, 15, 479-495, 19900401
- On solutions to some quasilinear hyperbolic equations with nonlinear inhomogeneous terms, Nonlinear Analysis TMA, 17, 181-203, 19910401
- A class of second order quasilinear evolution equations, 785, 95-111, 19920401
- A class of second order quasilinear evolution equations (with N.Okazawa), J. Differential Equations., 114(1), 106-131, 19940401
- A note on the global solvability of solutions to some nonlinear wave equations with dissipative terms, Differential and Integral Equations, 8(3), 607-616, 19950401
- Stable and unstable sets for evolution equations of parabolic and hyperbolic type (with T.Suzuki), Hiroshima Math. J., 26(3), 475-491, 19960401
- On global solutions and energy decay for the wave equations of Kirchhoff type with nonlinear damping terms (with T.Matsuyama), J. Math. Anal. Appl., 204, 729-753, 19960401
- Energy decay for the wave equations of Kirchhoff type with linear damping terms (with T.Matsuyama), Math. Japon., 45(2), 315-335, 19970401
- The global behavior of weak solutions to some nonlinear wave equations, Gakuto International Series, Math. Sci. Appl. Nonlinear Wavers, 10, 163-168, 19970401
- Finite and Infinite Time Blowup of Solutions to Some Semilinear Parabolic Equations, 1061, 43-50, 19980401
- The Palais-Smale Condition for some semilinear parabolic Equations, 1123, 76-82, 20000401
- Semilinear parabolic equations involving critical Sobolev exponent : local and asymptotic behavior of solutions (with T.Suzuki), Differential and Integral Equations, 13, 869-901, 20000401
- Remarks on the decay rate for the energy of the dissipative linear wave equations in exterior domains (with A.Saeki), SUT J. Math., 36(2), 267-277, 20000401
- Remalks on the behaviour of solutions to the linear wave equations in unbounded domains (with T.Matsuyama), Proc. School Sci. Tokai University, 36(1), 1-13, 20010401
- The Palais-Smale Condition for the energy of some semilinear parabolic equations, Hiroshima Math. J., 30, 117-127, 20000401
- Global solutions to the initial-boundary value problem for the quasilinear visco-elastic wave equations with a perturbation (with T.Matsuyama and M.Nakao), Funkcial. Ekvac., 40, 293-312, 19970401
- ★, Some remarks on the wave equations with nonlinear damping and source terms, Nonlinear Analysis TMA, 27, 1165-1175, 19960401
- L^{2}-behaviour of solutions to the linear heat and wave equations in an exterior domain (with T.Matsuyama), Sci. Math. Japon., 55, 33-42, 20020401
- Energy decay of solutions for the semilinear dissipative wave equations in an exterior domain, Funkcial. Ekvac., 44, 487-499, 20010401
- Small data global existence of solutions for dissipative wave equations in an exterior domain, Funkcial. Ekvac., 45, 259-269, 20020401
- Decay estimates by moments and masses of initial data for linear damped wave equations, International J. Pure Appl. Math., 5, 77-94, 20030401
- A remark on a critical exponent for the semilinear dissipative wave equation in the one dimensional half space, Differential and Integral Equations, 16, 727-736, 20030401
- Recent progress for dissipative wave equations in unbounded domains, Seminar Notes of Mathematical Sciences, Ibaraki University (Soga H. et al. eds.), 5, 12-25, 20020201
- Recent development of a damped wave equation in unbounded domain, Seminar Notes of Mathematical Sciences, Ibaraki University (Soga H. et al. eds.), 6, 51-58, 20030201
- Some remarks on the wave equation with potential type damping coefficients, International J. Pure Appl. Math., 21(1), 19-24, 20050401
- ★, Local energy decay for linear wave equations with initial data decaying slowly near infinity (with K. Nishihara), Gakuto International Series, Math. Sci. Appl., The 5th East Asia PDE Conference, 22, 265-275, 20050301
- Local energy decay for some hyperbolic equations with initial data decaying slowly near infinity (with G. Sobukawa)., Hokkaido Mathematical Journal, 36(1), 53-71, 20070401
- Decay estimates of solutions for the wave equations with strong damping terms in unbounded domains, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, 24(9), 659-670, 200106
- Remark on the L-2 estimates of the density for the compressible Navier-Stokes flow in R-3, NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS, 47(4), 2519-2526, 200108
- Critical exponents for semilinear dissipative wave equations in R-N, JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, 269(1), 87-97, 20020501
- Diffusion phenomenon for linear dissipative wave equations in an exterior domain, JOURNAL OF DIFFERENTIAL EQUATIONS, 186(2), 633-651, 20021210
- ★, Fast decay of solutions for linear wave equations with dissipation localized near infinity in an exterior domain, JOURNAL OF DIFFERENTIAL EQUATIONS, 188(2), 390-405, 20030301
- Improved decay rates for solutions to one-dimensional linear and semilinear dissipative wave equations in all space, JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, 277(2), 555-570, 20030115
- L-2-convergence results for linear dissipative wave equations in unbounded domains, ASYMPTOTIC ANALYSIS, 36(1), 63-74, 200310
- Diffusion phenomenon for second order linear evolution equations, STUDIA MATHEMATICA, 158(2), 153-161, 2003
- Critical exponent for semilinear damped wave equations in the N-dimensional half space, JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, 288(2), 803-818, 20031215
- Local energy decay for linear wave equations with variable coefficients, JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, 306(1), 330-348, 20050601
- Local Energy Decay for Linear Wave Equations with Localized Dissipation, FUNKCIALAJ EKVACIOJ-SERIO INTERNACIA, 48(3), 351-366, 200512
- Global existence of solutions for semilinear damped wave equation in 2-D exterior domain, JOURNAL OF DIFFERENTIAL EQUATIONS, 200(1), 53-68, 20040601
- ★, Decay estimates of solutions for dissipative wave equations in R-N with lower power nonlinearities, JOURNAL OF THE MATHEMATICAL SOCIETY OF JAPAN, 56(2), 365-373, 200404
- New decay estimates for linear damped wave equations and its application to nonlinear problem, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, 27(8), 865-889, 20040525
- Local energy decay for linear wave equations with non-compactly supported initial data, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, 27(16), 1881-1892, 20041110
- Two dimensional exterior mixed problem for semilinear damped wave equations, JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, 301(2), 366-377, 20050115
- ★, Global existence of solutions for semilinear damped wave equations in R-N with noncompactly supported initial data, NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS, 61(7), 1189-1208, 20050615
- Global asymptotics of solutions to the Cauchy problem for the damped wave equation with absorption, JOURNAL OF DIFFERENTIAL EQUATIONS, 226(1), 1-29, 20060701
- Global existence of solutions for 2-D semilinear wave equations with dissipation localized near infinity in an exterior domain, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, 29(4), 479-496, 20060310
- Decay of solutions for a semilinear system of elastic waves in an exterior domain with damping near infinity, NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS, 67(2), 398-429, 20070715
- Global existence of weak solutions for two-dimensional semilinear wave equations with strong damping in an exterior domain, NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS, 68(1), 154-169, 20080101
- Total energy decay for semilinear wave equations with a critical potential type of damping, NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS, 69(4), 1396-1401, 20080815
- Critical Exponent for Semilinear Wave Equations with Space-Dependent Potential, FUNKCIALAJ EKVACIOJ-SERIO INTERNACIA, 52(3), 411-435, 200912
- Local energy decay for a class of hyperbolic equations with constant coefficients near infinity, MATHEMATISCHE NACHRICHTEN, 283(5), 636-647, 201005
- Semi linear parabolic equation in R-N associated with critical Sobolev exponent, ANNALES DE L INSTITUT HENRI POINCARE-ANALYSE NON LINEAIRE, 27(3), 877-900, 2010
- Energy decay rates of elastic waves in unbounded domain with potential type of damping, JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, 380(1), 46-56, 20110801
- ★, Wave equations with strong damping in Hilbert spaces, JOURNAL OF DIFFERENTIAL EQUATIONS, 254(8), 3352-3368, 20130415
- Sharp decay rates for wave equations with a fractional damping via new method in the Fourier space, JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, 408(1), 247-255, 20131201
- NEW DECAY RATES FOR A PROBLEM OF PLATE DYNAMICS WITH FRACTIONAL DAMPING, JOURNAL OF HYPERBOLIC DIFFERENTIAL EQUATIONS, 10(3), 563-575, 201309
- Optimal decay rates for the system of elastic waves in R-n with structural damping, JOURNAL OF EVOLUTION EQUATIONS, 14(1), 197-210, 201403
- ★, Asymptotic profiles for wave equations with strong damping, JOURNAL OF DIFFERENTIAL EQUATIONS, 257(6), 2159-2177, 20140915
- ★, Some remarks on the asymptotic profiles of solutions for strongly damped wave equations on the 1-D half space, JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, 421(1), 905-916, 20150101
- Asymptotic behavior for abstract evolution differential equations of second order, JOURNAL OF DIFFERENTIAL EQUATIONS, 259(10), 5017-5039, 20151115
- ASYMPTOTIC PROFILES FOR A STRONGLY DAMPED PLATE EQUATION WITH LOWER ORDER PERTURBATION, COMMUNICATIONS ON PURE AND APPLIED ANALYSIS, 14(5), 1759-1780, 201509
- Fast energy decay for wave equations with variable damping coefficients in the 1-D half line, Differential and Integral Equations, 29(5,6), 421-440, 2016
- Optimal decay rates and asymptotic profile for the plate equation with structural damping, J. Math. Analysis and Applications, 440, 529-560, 20160323
- ★, Asymptotic profile of solutions for wave equations with frictional and viscoelastic damping terms, Asymptotic Analysis, 98(1-2), 59-77, 2016
- FAST ENERGY DECAY FOR WAVE EQUATIONS WITH VARIABLE DAMPING COEFFICIENTS IN THE 1-D HALF LINE, DIFFERENTIAL AND INTEGRAL EQUATIONS, 29(5-6), 421-440, 2016
- Critical exponent for nonlinear wave equations with frictional and viscoelastic damping terms, NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS, 148, 228-253, 201701
- REMARKS ON LARGE TIME BEHAVIOR OF THE L-2-NORM OF SOLUTIONS TO STRONGLY DAMPED WAVE EQUATIONS, DIFFERENTIAL AND INTEGRAL EQUATIONS, 30(7-8), 505-520, 2017
- Remarks on the Decay Rate of the Energy for Damped Modified Boussinesq-Beam Equations on the 1-D Half Line, FUNKCIALAJ EKVACIOJ-SERIO INTERNACIA, 60(2), 239-257, 201708
- Fast energy decay for wave equations with a localized damping in the n-D half space, Asymptotic Analysis, 103(1-2), 77-94, 2017
- ★, Asymptotic profile of solutions for some wave equations with very strong structural damping, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, 41(13), 5074-5090, 20180915
- Asymptotic profile of solutions for strongly damped Klein-Gordon equations, MATHEMATICAL METHODS IN THE APPLIED SCIENCES, 42(7), 2287-2301, 20190515
- Asymptotic Profiles of Solutions for Structural Damped Wave Equations, JOURNAL OF DYNAMICS AND DIFFERENTIAL EQUATIONS, 31(1), 537-571, 201903
- OPTIMAL ENERGY DECAY RATES FOR SOME WAVE EQUATIONS WITH DOUBLE DAMPING TERMS, EVOLUTION EQUATIONS AND CONTROL THEORY, 8(4), 825-846, 201912
- Note on asymptotic profile of solutions to the linearized compressible Navier-Stokes flow, HOKKAIDO MATHEMATICAL JOURNAL, 48(2), 357-383, 201906
- Moment conditions and lower bounds in expanding solutions of wave equations with double damping terms, ASYMPTOTIC ANALYSIS, 114(1-2), 19-36, 2019
- LARGE TIME BEHAVIOR OF GLOBAL SOLUTIONS TO NONLINEAR WAVE EQUATIONS WITH FRICTIONAL AND VISCOELASTIC DAMPING TERMS, OSAKA JOURNAL OF MATHEMATICS, 56(4), 807-830, 201910
- Critical exponent for semi-linear wave equations with double damping terms in exterior domains, NODEA-NONLINEAR DIFFERENTIAL EQUATIONS AND APPLICATIONS, 26(6), 201912
- Some remarks on the local energy decay for wave equations in the whole space, Azerbaijan J. Mathematics, 9(2), 167-182, 2019, July
- A note on decay rates of the local energy for wave equations with Lipschitz wavespeeds, JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, 483(2), 20200315
- A SECOND ORDER FRACTIONAL DIFFERENTIAL EQUATION UNDER EFFECTS OF A SUPER DAMPING, COMMUNICATIONS ON PURE AND APPLIED ANALYSIS, 19(9), 4433-4454, 202006
- Uniform Energy Decay for Wave Equations with Unbounded Damping Coefficients, FUNKCIALAJ EKVACIOJ-SERIO INTERNACIA, 63(1), 133-152, 202004
- Thresholds for low regularity solutions to wave equations with structural damping, JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS, 494(2), 124669, 20210215
- Asymptotic profiles for damped plate equations with rotational inertia terms, JOURNAL OF HYPERBOLIC DIFFERENTIAL EQUATIONS, 17(3), 569-589, 202009
- A note on optimal L-2-estimates of solutions to some strongly damped sigma-evolution equations, ASYMPTOTIC ANALYSIS, 121(1), 59-74, 2020

### Invited Lecture, Oral Presentation, Poster Presentation

- Asymptotic profiles for wave equation with strong damping., Ryo Ikehata, With Invitation, Japanese
- Asymptotic profiles for wave equation with strong damping., 2015/12/11, With Invitation, Japanese, other
- Fast energy decay for wave equations with a localized damping in the n-D half space, Ryo IKEHATA, Seminar on Partial Differential Equations at UFSC, Brasil, 2016/12/16, With Invitation, English, Federal University of Santa Catarina, Department of Mathematics, Federal University of Santa Catarina, Florianopolis, Brazil, other

## External Funds

### Acceptance Results of Competitive Funds

- KAKENHI, 2015, 2019
- KAKENHI, Energy decay for hyperbolic partial differential equations with variable coefficients and its related topic, 2010, 2013
- KAKENHI, 2010, 2014
- KAKENHI, Energy estimates for hyperbolic equations in unbounded domains and their applications, 2007, 2009
- KAKENHI, A study on asymptotic behavior of solutions for evolution equations, 2002, 2004
- KAKENHI, 1998, 1999