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Université de Fribourg

Structural effects on synchronizability of scale-free networks

Liu, Jian-Guo ; Zhou, Tao ; Guo, Qiang ; Wang, Bing-Hong

In: International Journal of Modern Physics C, 2008, vol. 19, no. 9, p. 1359 - 1366

In this paper, we numerically investigate the structural characteristics that affect the synchronizability of coupled identical oscillators on scale-free networks. By using the edge-exchange method, we can change the network structure with degree sequence fixed. An optimal algorithm, namely Tabu Search, is applied, respectively, to enhance and weaken the synchronizability. The numerical results...

Université de Fribourg

Scaling behaviour and memory in heart rate of healthy human

Cai, Shi-Min ; Peng, Hu ; Yang, Hui-Jie ; Zhou, Tao ; Zhou, Pei-Ling ; Wang, Bing-Hong

In: Chinese Physics Letters, 2007, vol. 24, no. 10, p. 3002

We investigate a set of complex heart rate time series from healthy human in different behaviour states with the detrended fluctuation analysis and diffusion entropy (DE) method. It is proposed that the scaling properties are influenced by behaviour states. The memory detected by DE exhibits an approximately same pattern after a detrending procedure. Both of them demonstrate the long-range strong...

Université de Fribourg

Scale invariance of human electroencephalogram signals in sleep

Cai, Shi-Min ; Jiang, Zhao-Hui ; Zhou, Tao ; Zhou, Pei-Ling ; Yang, Hui-Jie ; Wang, Bing-Hong

In: Physical Review E, 2007, vol. 76, p. 061903

In this paper, we investigate the dynamical properties of electroencephalogram (EEG) signals of humans in sleep. By using a modified random walk method, we demonstrate that scale-invariance is embedded in EEG signals after a detrending procedure is applied. Furthermore, we study the dynamical evolution of the probability density function (PDF) of the detrended EEG signals by nonextensive...

Université de Fribourg

Reducing the heterogeneity of payoffs: an effective way to promote cooperation in the prisoner's dilemma game

Jiang, Luo-Luo ; Zhao, Ming ; Yang, Han-Xin ; Wakeling, Joseph Rushton ; Wang, Bing-Hong ; Zhou, Tao

In: Physical Review E, 2009, vol. 80, p. 031144

In this paper, the accumulated payoff of each agent is regulated so as to reduce the heterogeneity of the distribution of all such payoffs. It is found that there exists an optimal regulation strength at which cooperation in the prisoner's dilemma game is optimally promoted. If the heterogeneity is regulated to be either too weak or too strong, the promotive effect disappears and the evolution of...

Université de Fribourg

Personal recommendation via modified collaborative filtering

Liu, Run-Ran ; Jia, Chun-Xiao ; Zhou, Tao ; Sun, Duo ; Wang, Bing-Hong

In: Physica A: Statistical Mechanics and its Applications, 2009, vol. 388, no. 4, p. 462-468

In this paper, we propose a novel method to compute the similarity between congeneric nodes in bipartite networks. Different from the standard cosine similarity, we take into account the influence of a node’s degree. Substituting this new definition of similarity for the standard cosine similarity, we propose a modified collaborative filtering (MCF). Based on a benchmark database, we...

Université de Fribourg

Optimal view angle in collective dynamics of self-propelled agents

Tian, Bao-Mei ; Yang, Han-Xin ; Li, Wei ; Wang, Wen-Xu ; Wang, Bing-Hong ; Zhou, Tao

In: Physical Review E, 2009, vol. 79, no. 5, p. 052102

We study a system of self-propelled agents with the restricted vision. The field of vision of each agent is only a sector of disk bounded by two radii and the included arc. The inclination of these two radii is characterized by the view angle. The consideration of restricted vision is closer to the reality because natural swarms usually do not have a panoramic view. Interestingly, we find that...

Université de Fribourg

Optimal contact process on complex networks

Yang, Rui ; Zhou, Tao ; Xie, Yan-Bo ; Lai, Ying-Cheng ; Wang, Bing-Hong

In: Physical Review E, 2008, vol. 78, no. 6, p. 066109

Contact processes on complex networks are a recent subject of study in nonequilibrium statistical physics and they are also important to applied fields such as epidemiology and computer and communication networks. A basic issue concerns finding an optimal strategy for spreading. We provide a universal strategy that, when a basic quantity in the contact process dynamics, the contact probability...

Université de Fribourg

Opinion spreading with mobility on scale-free networks

Guo, Qiang ; Liu, Jian-Guo ; Wang, Bing-Hong ; Zhou, Tao ; Chen, Xing-Wen ; Yao, Yu-Hua

In: Chinese Physics Letters, 2008, vol. 25, no. 2, p. 773-775

A continuum opinion dynamic model is presented based on two rules. The first one considers the mobilities of the individuals, the second one supposes that the individuals update their opinions independently. The results of the model indicate that the bounded confidence ∈c, separating consensus and incoherent states, of a scale-free network is much smaller than the one of a...

Université de Fribourg

Opinion dynamics on directed small-world networks

Jiang, L. -L. ; Hua, D. -Y. ; Zhu, J. -F. ; Wang, Bing-Hong ; Zhou, Tao

In: The European Physical Journal B, 2008, vol. 65, no. 2, p. 251-255

We investigate the self-affirmation effect on formation of public opinion in a directed small-world social network. The system presents a non-equilibrium phase transition from a consensus state to a disordered state with coexistence of opinions. The dynamical behaviors are very sensitive to the density of long-range-directed interactions and the strength of self-affirmation. When the...

Université de Fribourg

Modeling human dynamics with adaptive interest

Han, Xiao-Pu ; Zhou, Tao ; Wang, Bing-Hong

In: New Journal of Physics, 2008, vol. 10, p. 073010

Increasing recent empirical evidence indicates the extensive existence of heavy tails in the inter-event time distributions of various human behaviors. Based on the queuing theory, the Barabási model and its variations suggest the highest-priority-first protocol to be a potential origin of those heavy tails. However, some human activity patterns, also displaying heavy-tailed temporal statistics,...