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Université de Fribourg

Emergence of target waves in paced populations of cyclically competing species

Jiang, Luo-Luo ; Zhou, Tao ; Perc, Matjaž ; Huang, Xin ; Wang, Bing-Hong

In: New Journal of Physics, 2009, vol. 11, p. 103001

We investigate the emergence of target waves in a cyclic predator–prey model incorporating a periodic current of the three competing species in a small area situated at the center of a square lattice. The periodic current acts as a pacemaker, trying to impose its rhythm on the overall spatiotemporal evolution of the three species. We show that the pacemaker is able to nucleate target waves that...

Université de Fribourg

Effects of social diversity on the emergence of global consensus in opinion dynamics

Yang, Han-Xin ; Wu, Zhi-Xi ; Zhou, Changsong ; Zhou, Tao ; Wang, Bing-Hong

In: Physical Review E, 2009, vol. 80, no. 4, p. 046108

We propose a variant of the voter model by introducing the social diversity in the evolution process. Each individual is assigned a weight that is proportional to the power of its degree, where the power exponent α is an adjustable parameter that controls the level of diversity among individuals in the network. At each time step, a pair of connected individuals, say i and j, are...

Université de Fribourg

Predicting missing links via local information

Zhou, Tao ; Lü, Linyuan ; Zhang, Yi-Cheng

In: The European Physical Journal B, 2009, vol. 71, no. 4, p. 623-630

Missing link prediction in networks is of both theoretical interest and practical significance in modern science. In this paper, we empirically investigate a simple framework of link prediction on the basis of node similarity. We compare nine well-known local similarity measures on six real networks. The results indicate that the simplest measure, namely Common Neighbours, has the best overall...

Université de Fribourg

Information filtering based on transferring similarity

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

In: Physical Review E, 2009, vol. 80, no. 1, p. 017101

n this Brief Report, we propose an index of user similarity, namely, the transferring similarity, which involves all high-order similarities between users. Accordingly, we design a modified collaborative filtering algorithm, which provides remarkably higher accurate predictions than the standard collaborative filtering. More interestingly, we find that the algorithmic performance will approach...

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

Local preferential attachment model for hierarchical networks

Wang, Li-Na ; Guo, Jin-Li ; Yang, Han-Xin ; Zhou, Tao

In: Physica A: Statistical Mechanics and its Applications, 2009, vol. 388, no. 8, p. 1713-1720

A railway transportation system can be represented by a bipartite network consisting of trains and stations, where a train is connected to all stations where it stops. In this paper, motivated by the resource-allocation process taking place on networks, we design a method to project a Chinese train-station bipartite network into a weighted station network. A new metric is proposed to quantify the...

Université de Fribourg

Empirical analysis of dependence between stations in Chinese railway network

Wang, Yong-Li ; Zhou, Tao ; Shi, Jian-Jun ; Wang, Jian ; He, Da-Ren

In: Physica A: Statistical Mechanics and its Applications, 2009, vol. 388, no. 14, p. 2949-2955

A railway transportation system can be represented by a bipartite network consisting of trains and stations, where a train is connected to all stations where it stops. In this paper, motivated by the resource-allocation process taking place on networks, we design a method to project a Chinese train-station bipartite network into a weighted station network. A new metric is proposed to quantify the...

Université de Fribourg

Accelerating consensus of self-driven swarm via adaptive speed

Zhang, Jue ; Zhao, Yang ; Tian, Baomei ; Peng, Liqian ; Zhang, Hai-Tao ; Wang, Bing-Hong ; Zhou, Tao

In: Physica A: Statistical Mechanics and its Applications, 2009, vol. 3888, no. 7, p. 1237-1242

In recent years, the well-developed Vicsek model has attracted more and more attention. Unfortunately, in-depth research on its convergence speed is not yet completed. In this paper, we investigate some key factors governing the convergence speed of the Vicsek model with the assistance of extensive numerical simulations. A significant phenomenon surfaces that the convergence time scales obeys a...

Université de Fribourg

Predictive protocol of flocks with small-world connection pattern

Zhang, Hai-Tao ; Chen, Michael Z. Q. ; Zhou, Tao

In: Physical Review E, 2009, vol. 79, no. 01, p. 016113

By introducing a predictive mechanism with small-world connections, we propose a new motion protocol for self-driven flocks. The small-world connections are implemented by randomly adding long-range interactions from the leader to a few distant agents, namely, pseudoleaders. The leader can directly affect the pseudoleaders, thereby influencing all the other agents through them efficiently....

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...