Biomedical subjects

In-Mook Kim

Publications and source records attributed to In-Mook Kim.

7 recordsLinked to original sources

PubMed2005

Absorbing phase transition with a conserved field.

We study a lattice gas model where the number of particles is conserved during dynamical process. Our model shows a continuous phase transition from a fluctuating phase to two symmetric absorbing states at the critical point in one dimension. We conjecture the values of the critical exponents characterizing the phase transition of our model. We show that the obtained values are in good agreement with those estimated from computer simulations. The critical exponents indicate that our model exhibits an absorbing phase transition which is different from the known ones.

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PubMed2004

Growth of a tensionless interface in anisotropic random media.

We introduce a simple growth model where a tensionless interface grows in random media. In this model, the degree of anisotropy of the random media is controlled by a variable g. When g=0, there is no anisotropic property of the random media. But, the anisotropic property increases as g does from 0. From the numerical simulations, we find that this model belongs to the quenched Herring-Mullins universality class when g=0. Interestingly, however, we find that this model belongs to the quenched Kardar-Parisi-Zhang universality class when g is nonzero.

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PubMed2003

Transition from stable to unstable growth by an inertial force.

We introduce a simple growth model where the growth of the interface is affected by an inertial force and a white noise. The magnitude of the inertial force is controlled by a constant p between 0 and 1. An inertial force increases continuously from 0, as p does from 0 to 1. In our model, the interface starts growing from a flat state. When p p(c), however, the interface width increases continuously without saturation as time elapses. We explain via simple calculation how this interesting phenomenon occurs in our model. We find p(c)=0.5 from the calculation. This critical value is in excellent agreement with the critical value p(c)=0.50(1) found from the simulations of our model.

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PubMed2002

Self-organized interface growth with the negative nonlinearity in a random medium.

We introduce two self-organized growth models that describe the motion of the driven interfaces in random media including the Kardar-Parisi-Zhang (KPZ) nonlinearity. One model follows the quenched KPZ equation with a positive nonlinear term, while the other model follows the quenched KPZ equation with a negative nonlinear term. By obtaining the critical exponents for two models, we confirm that the sign of the KPZ nonlinear term does not affect the universality class.

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PubMed2002

Well-defined set of exponents for a pair contact process with diffusion.

Recently it was suggested that a pair contact process with diffusion (PCPD) might represent an independent new universality class different from the directed percolation (DP) and the parity conservation (PC) class. The dynamics in the PCPD are usually controlled by two independent parameters. The critical exponents for the PCPD are known to have different values for varying values of the two independent parameters. However, once the diffusion and annihilation (or coagulation) rate in the PCPD is tuned in a way that the process without offspring production is exactly solvable, a well-defined set of the exponents for the PCPD is obtained. Then dynamics are controlled by only one independent parameter. The obtained critical exponents are different than those of DP and PC. The critical exponents satisfy the generalized hyperscaling relation within numerical errors.

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PubMed2002

Phase transition in a triplet process.

We argue that the reaction-diffusion process 3A-->4A,3A-->2A exhibits a different type of continuous phase transition from an active into an absorbing phase. Because of the upper critical dimension d(c)> or =4/3 we expect the phase transition in 1+1 dimensions to be characterized by nontrivial fluctuation effects.

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PubMed2002

First-order transition in a particle deposition-evaporation model.

We introduce a simple stochastic growth model where particles of two different species are deposited and evaporated. In the model, a randomly chosen particle of two species is deposited at a rate p and a particle on the edge of the plateau of the interface is evaporated at a rate 1-p. When p p(c2)=0.5015(5), the velocity of the interface is zero. When p(c1)</=p</=p(c2), however, the interface grows with a constant velocity. At both p(c1) and p(c2), the velocity of the interface changes from zero to a constant value discontinuously. The first-order transitions in our model are related to a nonequilibrium phase transition from an active to an inactive phase at the bottom layer of the interface. Interestingly, the first-order transition at p(c1) is triggered by the combination of the parity conserving and the directed percolation dynamics. We explain why the transitions in our model are of first order. Moreover, our model shows two nonequilibrium roughening transitions at p(c1) as well as at p(r)[=0.444(2)].

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