Biomedical subjects

Sheng-You Huang

Publications and source records attributed to Sheng-You Huang.

7 recordsLinked to original sources

PubMed2003

Critical behavior of efficiency dynamics in small-world networks.

Some dynamical processes in a small-world network shows a critical transition at a finite disorder phi(c) of the network, in contrast with the geometrical properties that exhibit the critical behavior at phi(c)=0. Although it has been pointed out in previous works that the transition is related to the structural properties of the network, it is still not very clear why the transition occurs at phi(c) not equal 0. In this paper we present a simple social model of efficiency dynamics in small-world networks, which also shows a transition at phi(c)>0. We obtain the critical point with phi(c) approximately equal 0.098 from the finite-size analysis. It is found that both the geometrical properties of the network and the specific dynamical characters of the model contribute to the critical transition. This work is useful for understanding this kind of transition occurring in many dynamical processes in small-world networks.

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PubMed2003

Network-induced nonequilibrium phase transition in the "game of Life".

A cellular automation model of the "game of Life" on a two-dimensional small-world network is presented in order to count in long-range interactions among living individuals in social or biological systems. The density of the life and its fluctuation are calculated, respectively. The present model exhibits a nonequilibrium phase transition from an "inactive-sparse" state to an "active-dense" one at a certain intermediate value of the network disorder. Employing finite-size scaling analysis, we estimate the location of the critical point with p(c)( infinity ) approximately 0.3685. The transition is of the "second-order" type with power-law diverging length. We obtain the critical exponents 1/nu approximately 1.70, beta approximately 0.50, and beta/nu approximately 0.85. The calculated results indicate that the present model may belong to the universality class of directed percolation.

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PubMed2002

Multiparticle random walks on a deformable medium.

Multiparticle random walks on a deformable medium have been investigated in (2+1) dimensions. The time evolution of the particle distribution is studied. The results show that the randomly distributed particles in the beginning will be self-organized into a cluster pattern in the intermediate stage, and then return to the random distribution pattern in the late stage. The dependence of the clustering degree on the stiffness parameter of medium alpha, stability parameter of systems beta, and average particle density rho(0) is also investigated. There exists an optimal clustering stability beta(p), at which the system has the strongest clustering ability and corresponds to a maximum clustering coefficient Gamma(*)(p). The dependence of the optimal clustering coefficient Gamma(*)(p) on the stiffness alpha and particle density rho(0) is obtained, and the landscape of the medium generated by particles is also investigated.

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PubMed2002

Patterns of particle distribution in multiparticle systems by random walks with memory enhancement and decay.

We investigate the pattern of particle distribution and its evolution with time in multiparticle systems using the model of random walks with memory enhancement and decay. This model describes some biological intelligent walks. With decrease in the memory decay exponent alpha, the distribution of particles changes from a random dispersive pattern to a locally dense one, and then returns to the random one. Correspondingly, the fractal dimension D(f,p) characterizing the distribution of particle positions increases from a low value to a maximum and then decreases to the low one again. This is determined by the degree of overlap of regions consisting of sites with remanent information. The second moment of the density rho(2) was introduced to investigate the inhomogeneity of the particle distribution. The dependence of rho(2) on alpha is similar to that of D(f,p) on alpha. rho(2) increases with time as a power law in the process of adjusting the particle distribution, and then rho(2) tends to a stable equilibrium value.

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PubMed2002

Directed random walks in continuous space.

The investigation on diffusion with directed motion in a two-dimensional continuous space is completed by using the model of the continuous directed random walks. The average square end-to-end distance approximately t(2nu) is calculated. The results show that this type of walks belongs asymptotically to the same class (nu=1.0) as the ballistic motions. For short time, we observe a crossover from purely random walks (nu=0.5) to ballistic motions (nu=1.0). The dependence of the crossover on the direction parameter theta is studied. There exists a scaling relation of the form approximately tf(t/theta(-2)). The return probability P00(t) is also investigated and the scaling form similar to is obtained.

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PubMed2002

Random walk with memory enhancement and decay.

A model of random walk with memory enhancement and decay was presented on the basis of the characteristics of the biological intelligent walks. In this model, the movement of the walker is determined by the difference between the remaining information at the jumping-out site and jumping-in site. The amount of the memory information s(i)(t) at a site i is enhanced with the increment of visiting times to that site, and decays with time t by the rate e(-beta(t)), where beta is the memory decay exponent. When beta=0, there exists a transition from Brownian motion (BM) to the compact growth of walking trajectory with the density of information energy u increasing. But for beta>0, this transition does not appear and the walk with memory enhancement and decay can be considered as the BM of the mass center of the cluster composed of remembered sites in the late stage.

Animals↗

PubMed2002

Random walks on a ( 2+1)-dimensional deformable medium.

A model of random walks on a deformable medium is proposed in 2+1 dimensions. The behavior of the walk is characterized by the stability parameter beta and the stiffness exponent alpha. The average square end-to-end distance l approximately equals (2nu) and the average number of visited sites approximately equals (k) are calculated. As beta increases, for each alpha there exists a critical transition point beta(c) from purely random walks ( nu = 1/2 and k approximate to 1) to compact growth ( nu = 1/3 and k = 2/3). The relationship between beta(c) and alpha can be expressed as beta(c) = e(alpha). The landscape generated by a walk is also investigated by means of the visit-number distribution N(n)(beta). There exists a scaling relationship of the form N(n)(beta)approximately n(-2)f(n/beta(z)).

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