Osaka Kyoiku University Researcher Information
日本語 | English
研究者業績
基本情報
- 所属
- 大阪教育大学 理数情報教育系 教授
- 学位
- 修士(工学)(大阪大学)博士(理学)(大阪大学)
- 研究者番号
- 70283843
- J-GLOBAL ID
- 200901015350849187
- researchmap会員ID
- 5000026358
経歴
4-
2007年4月
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2003年1月 - 2007年3月
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2001年4月 - 2002年12月
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1996年4月 - 2001年3月
学歴
1-
1991年4月 - 1994年3月
論文
21-
Physical Review E 105 044130 2022年4月21日 査読有り
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Physical Review E 101 042102 2020年4月3日 査読有り
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Physical Review E 99 063304 2019年6月11日 査読有り
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Physica A 491 1014-1022 2018年 査読有り
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PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 436 321-326 2015年10月 査読有りWe consider inference in the inverse Ising problem using full data, which means incorporating sets of spin configurations. We approximate the Boltzmann distribution of the system to generate a frequency distribution derived from the given data. Then, the ratio between two Boltzmann distributions with different spin configurations eliminates the partition function and we obtain linear equations which can be solved to yield statistical parameters. Our method is applicable to cases where the absolute values of the coupling parameters and external fields are large. Compared to pseudolikelihood maximization, the accuracy of the inference obtained from our method is similar, although our approach is less labor intensive. (C) 2015 Elsevier B.V. All rights reserved.
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Physical Review E 89 062135 2014年6月26日 査読有り
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Physica A 391(6) 2215-2224 2012年3月 査読有り
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Physics of Fluids 15(9) 2480-2485 2003年9月 査読有り
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JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 71(12) 2907-2917 2002年12月 査読有りWe investigate stability of a cylindrical domain in a phase-separating binary fluid under a Poiseuille flow. Linearization for a couple of the Navier-Stokes and Cahn-Hilliard equations around stationary solutions leads to an eigenvalue problem, a solution of which yields a stability eigenvalue. The stability eigenvalue is composed of a term originated from the hydrodynamic Rayleigh instability and that from the diffusive instability. Concerning the stability eigenvalue of the hydrodynamic instability, a set of equations is obtained from boundary conditions at an interface and a solution of the equations yields the stability eigenvalue. In case of equal viscosity, the analytic formula of the solution is obtained without an external flow. The Tomotika's stability eigenvalue with the equal viscosity [Proc. R. Soc. London, Ser. A 150 (1935) 322] is shown to agree with the Stone and Brenner's result [J. Fluid Mech. 318 (1996) 373] explicitly. The Poiseuille flow has an effect of mixing an unstable axisymmetric mode with stable nonaxisymmetric modes, so that the two instability are suppressed. A radius of a stable cylindrical domain depends on a distance from the center of the Poiseuille flow. We estimate a Reynolds number under an external flow. Validity of the Stokes' approximation for the Navier-Stokes equation is confirmed.
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JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 71(1) 60-66 2002年1月 査読有りWe investigate effect of external flow on domains in two-dimensional phase-separating binary fluid. By use of the coupled Cahn-Hillard and Navier-Stokes equations, we study stability of a lamellar domain under two-dimensional Poiseuille flow within a linear stability analysis. We derive stability eigenvalues for long wavelength fluctuations. The two-dimensional Poiseuille now has the effect if mixing a stable zigzag mode and an unstable varicose mode so that they both become Stable. The width of the stable lamellar domain depends on a distance from wall.
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大阪教育大学紀要 第III部門 : 自然科学・応用科学 49(1) 119-129 2000年8月
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Journal of Physics: Condensed Matter 7(26) 5045-5051 1995年 査読有りWe study the magnetic properties of the one-dimensional Hubbard model under fixed chemical potential. By using derivatives of the Lieb-Wu equation, the magnetization curve at zero temperature is obtained for various fixed band fillings and/or chemical potentials. As a well known result, in the case of the fixed band filling, there is only one second-order phase transition at magnetic saturation. On the other hand, when the chemical potential is fixed instead of the electron density, it is found that there is an additional phase transition in the magnetization curve.
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Journal of Physics: Condensed Matter 7(41) 7991-7996 1995年 査読有りIt has been shown that there exists an additional magnetic phase transition of the magnetization curve for the S=1 SU(3) antiferromagnetic spin chain at zero temperature. As a the magnetic field decreases from the saturation field, there is a phase change at a critical field hc, where the magnetization curve versus the magnetic field has a cusp. The critical field is a boundary between two states, one of which contains the particles with the spin +1 and 0 and the other with the spin +1, 0 and -1. In this paper we estimate the critical field hc of the phase transition by examining the stability of these states.
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JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 63(12) 4269-4273 1994年12月 査読有りWe study the integrable SU(M) and SUq(M) quantum spin chains in the high-magnetic-field region at zero temperature. For M=4 we found second-order phase transitions at two different fields, H-1 and H-2. At both transition points, the magnetization curve versus magnetic field has cusps with discontinuities in the magnetic susceptibility. We clarify the mechanism of the phase transitions, from which we conclude that the SU(M) and SUq(M) quantum spin chains undergo (M-2) times field-induced phase transitions at zero temperature.
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Journal of the Physical Society of Japan 61(10) 3598-3608 1994年10月 査読有り
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JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 61(7) 2161-2164 1992年7月 査読有りFor the integrable long-range SU(M) spin chain, the exact ground-state wave function is constructed for arbitrary irreducible representation of the permutation group.
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JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN 61(5) 1441-1444 1992年5月 査読有りWe present an exactly solvable quantum SU(M) (M: arbitrary integer greater-than-or-equal-to 2) spin chain with long-range (approximately inverse-square) interactions. The model generalizes the so-called Haldane-Shastry system which corresponds to M = 2. We find the Lax pair for the system which guarantees the integrability of the system. An exact many-body ground-state wave function with particular symmetry is explicitly constructed.
MISC
2-
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL 41(33) 332004 2008年8月The hyperparameter in image restoration by the Bayes formula is an important quantity. This communication shows a physical method for the estimation of the hyperparameter without approximation. For artificially generated images by prior probability, the hyperparameter is computed accurately. For practical images, accuracy of the estimated hyperparameter depends on the magnetization and energy of the images. We discuss the validity of prior probability for an original image.
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PHYSICS OF FLUIDS 15(9) 2480-2485 2003年9月We investigate a stability of a lamellar domain in phase-separating binary fluids under an external flow. Using the Navier-Stokes and the Cahn-Hilliard equations, we take into account effects of diffusion and surface tension at an interface. Stability eigenvalues are evaluated for various values of the Peclet number, the spacing between the interfaces, and the Reynolds number. It is found that the lamellar domain becomes unstable at a finite wavenumber before the flow when the Reynolds number increases. The instability of the interface occurs on conditions that the interface is situated near a wall or the Peclet number is large. The instability stems from the interaction between disturbances of the flow and the diffusive interface. (C) 2003 American Institute of Physics.