arXiv subjects

Yong Chen

Publications and source records attributed to Yong Chen.

409 records · Page 23Linked to original sources

arXiv2007

Frequency and phase synchronization of two coupled neurons with channel noise

We study the frequency and phase synchronization in two coupled identical and nonidentical neurons with channel noise. The occupation number method is used to model the neurons in the context of stochastic Hodgkin-Huxley model in which the strength of of channel noise is represented by ion channel cluster size of the initiation region of neuron. It is shown that frequency synchronization only was achieved at arbitrary value of couple strength as long as two neurons' channel cluster sizes are the same. We also show that the relative phase of neurons can display profuse dynamic behavior under the combined action of coupling and channel noise. Both qualitative and quantitative descriptions are applied to describe the transitions between those behaviors. Relevance of our findings to controlling neural synchronization experimentally is discussed.

q-bio.NC↗

arXiv2007

Network growth approach to macroevolution

We propose a novel network growth model coupled with the competition interaction to simulate macroevolution. Our work shows that the competition plays an important role in macroevolution and it is more rational to describe the interaction between species by network structures. Our model presents a complete picture of the development of phyla and the splitting process. It is found that periodic mass extinction occurred in our networks without any extraterrestrial factors and the lifetime distribution of species is very close to fossil record. We also perturb networks with two scenarios of mass extinctions on different hierarchic levels in order to study their recovery.

q-bio.PE↗

arXiv2007

Statistical Neurodynamics for sequence processing neural networks with finite dilution

We extend the statistical neurodynamics to study transient dynamics of sequence processing neural networks with finite dilution, and the theoretical results is supported by the extensive numerical simulations. It is found that the order parameter equations are completely equivalent to those of the Generating Functional Method, which means that crosstalk noise is normal distribution even in the case of failure in retrieval process. In order to verify the gaussian assumption of crosstalk noise, we numerically obtain the cumulants of crosstalk noise, and third- and fourth-order cumulants are found to be indeed zero even in non-retrieval case.

cond-mat.dis-nn↗

arXiv2006

Bond-orientational Order in Melting of Colloidal Crystals

Using Brownian dynamics simulation, we study the orientational order in melting transition of colloidal systems with $'$soft$'$ Yukawa potential. The bond-orientational order parameter $Φ_{6}$ and the bond-orientational order function $g_B(r)$ are calculated in two-dimensional systems. It is found that a two-stage transition and the hexatic phase are indeed existent in two-dimensional melitng, which is consistent with the prediction of the Kosterlitz-Thouless-Halperin-Nelson-Young theory. For comparing with the melting process in three-dimensional systems, the probability distribution of single-particle local order parameter is introduced. Based on the extensive simulations, it is qualitatively suggested that the breakdown of local order only occurs on the fractional part of the colloidal systems for the two-dimensional melting, but in three-dimensional melting, this breakdown takes place on the whole systems at the same time.

cond-mat.dis-nn↗

arXiv2006

Optimized annealing of traveling salesman problem from the nth-nearest-neighbor distribution

We report a new statistical general property in traveling salesman problem, that the $n$th-nearest-neighbor distribution of optimal tours verifies with very high accuracy an exponential decay as a function of the order of neighbor $n$. With defining the energy function as the deviation $λ$ from this exponential decay, which is different to the tour length $d$ in normal annealing processes, we propose a distinct highly optimized annealing scheme which is performed in $λ$-space and $d$-space by turns. The simulation results of some standard traveling salesman problems in TSPLIB95 are presented. It is shown that our annealing recipe is superior to the canonical simulated annealing.

cond-mat.stat-mech↗

arXiv2006

Effect of Size Polydispersity on Melting of Charged Colloidal Systems

We introduce simple prescriptions of the Yukawa potential to describe the effect of size polydispersity and macroion shielding effect in charged colloidal systems. The solid-liquid phase boundaries were presented with the Lindemann criterion based on molecular dynamics simulations. Compared with the Robbins-Kremer-Grest simulation results, a deviation of melting line is observed at small $λ$, which means large macroion screening length. This deviation of phase boundary is qualitatively consistent with the simulation result of the nonlinear Poisson-Boltzmann equation with full many-body interactions. It is found that this deviation of the solid-liquid phase behaviour is sensitive to the screening parameter.

cond-mat.stat-mech↗

arXiv2005

Description of dynamics of stock prices by a Langevin approach

We present a time-dependent Langevin description of dynamics of stock prices. Based on a simple sliding-window algorithm, the fluctuation of stock prices is discussed in the view of a time-dependent linear restoring force which is the linear approximation of the drift parameter in Langevin equation estimated from the financial time series. By choosing suitable weighted factor for the linear approximation, the relation between the dynamical effect of restoring force and the autocorrelation of the financial time series is deduced. We especially analyze the daily log-returns of S$&$P 500 index from 1950 to 1999. The significance of the restoring force towards the prices evolution are investigated from its two coefficients, slope coefficient and equilibrium position. The new simple form of the restoring force obtained both from statistical and theoretical analyses suggests that the Langevin approach can effectively present the macroscopical and the detail properties of the price evolution.

physics.soc-ph↗

arXiv2005

Steady States of Epidemic Spreading in Small-World Networks

We consider a standard \textit{susceptible-infected-susceptible} (SIS) model to study behaviors of steady states of epidemic spreading in small-world networks. Using analytical methods and large scale simulations, we recover the usual epidemic behavior with a critical threshold $λ_{c}$ below which infectious diseases die out. Whereas for the spreading rate $λ$ far above $λ_{c}$, it was found that the density of infected individuals $ρ$ as a function of $λ$ has the property $ρ\approx F(K)(\ln λ- \ln λ_{c})$.

physics.soc-ph↗

arXiv2004

Evidence of a first order phase transition between Wigner crystal and Bubble Phases of 2D electrons in higher Landau levels

For filling factors $ν$ in the range between 4.16 and 4.28, we simultaneously detect {\it two} resonances in the real diagonal microwave conductivity of a two--dimensional electron system (2DES) at low temperature $T \approx 35$ mK. We attribute the resonances to Wigner crystal and Bubble phases of the 2DES in higher Landau Levels. For $ν$ below and above this range, only single resonances are observed. The coexistence of both phases is taken as evidence of a first order phase transition. We estimate the transition point as $ν=4.22$.

cond-mat.mes-hall↗

arXiv2003

Wigner crystalization about $ν$=3

We measure a resonance in the frequency dependence of the real diagonal conductivity, Re[$σ_{xx}$], near integer filling factor, $ν=3$. This resonance depends strongly on $ν$, with peak frequency $f_{pk} \approx 1.7$ GHz at $ν=3.04$ or 2.92 close to integer $ν$, but $f_{pk} \approx$ 600 MHz at $ν=3.19$ or 2.82, the extremes of where the resonance is visible. The dependence of $f_{pk}$ upon $n^*$, the density of electrons in the partially filled level, is discussed and compared with similar measurments by Chen {\it et al.}\cite{yong} about $ν=1$ and 2. We interpret the resonance as due to a pinned Wigner crystal phase with density $n^*$ about the $ν=3$ state.

cond-mat.mes-hall↗

arXiv2002

The macroscopic dynamics in separable neural networks

The parallel dynamics is given in the case of neural networks with separable coupling through starting from Coolen-Sherrington (CS) theory. It is shown that this retrieve dynamics as is the case of sequential evolution in the postulate of away from saturation and finite temperature. The finite-size effects is governed by a homogeneous Markov process, which differs from the time-dependent Ornstein-Uhlenbeck process in sequential dynamics. PACS number(s): 87.10.+e, 75.10.Nr, 02.50.+s

cond-mat.dis-nn↗

arXiv2002

Coupling parameter in synchronization of diluted neural networks

We study the critical features of coupling parameter in the synchronization of neural networks with diluted synapses. Based on simulations, the exponential decay form is observed in the extreme case of global coupling among subsystems and fully linking in each network: there exists maximum and minimum of the critical coupling intensity for synchronization in this spatially extended system. For the partial coupling, we present the primary result about the critical coupling fraction for various linking degrees of networks.

cond-mat.dis-nn↗

arXiv2002

The attractors in sequence processing neural networks

The average length and average relaxation time of attractors in sequence processing neural networks are investigated. The simulation results show that a critical point of $α$, the loading ratio, is found. Below the turning point, the average length is equal to the number of stored patterns; conversely, the ratio of length and numbers of stored patterns, grow with an exponential dependence $\exp (Aα) $. Moreover, we find that the logarithm of average relaxation time is only linearly associated with $α$ and the turning point of coupling degree is located for examining robustness of networks.

cond-mat.dis-nn↗