Université de Fribourg

Improving information filtering via network manipulation

Zhang, Fuguo ; Zeng, An

In: EPL - Europhysics Letters, 2012, vol. 100, no. 5, p. 58005

The recommender system is a very promising way to address the problem of overabundant information for online users. Although the information filtering for the online commercial systems has received much attention recently, almost all of the previous works are dedicated to design new algorithms and consider the user-item bipartite networks as given and constant information. However, many problems...

Université de Fribourg

Enhancing network robustness against malicious attacks

Zeng, An ; Liu, Weiping

In: Physical Review E - Statistical, Nonlinear and Soft Matter Physics, 2012, vol. 85, no. 6, p. 066130

In a recent work [ Schneider et al. Proc. Natl. Acad. Sci. USA 108 3838 (2011)], the authors proposed a simple measure for network robustness under malicious attacks on nodes. Using a greedy algorithm, they found that the optimal structure with respect to this quantity is an onion structure in which high-degree nodes form a core surrounded by rings of nodes with decreasing degree. However, in...

Université de Fribourg

Degree heterogeneity in spatial networks with total cost constraint

Liu, Weiping ; Zeng, An ; Zhou, Yanbo

In: EPL - Europhysics Letters, 2012, vol. 98, no. 2, p. 28003

Recently, Li et al. (Phys. Rev. Lett., 104 (2010) 018701) studied a spatial network which is constructed from a regular lattice by adding long-range edges (shortcuts) with probability Pij~rij−α, where rij is the Manhattan length of the long-range edges. The total length of the additional...

Université de Fribourg

Removing spurious interactions in complex networks

Zeng, An ; Cimini, Giulio

In: Physical Review E - Statistical, nonlinear, and soft matter physics, 2012, vol. 85, no. 3, p. 036101

Identifying and removing spurious links in complex networks is meaningful for many real applications and is crucial for improving the reliability of network data, which, in turn, can lead to a better understanding of the highly interconnected nature of various social, biological, and communication systems. In this paper, we study the features of different simple spurious link elimination methods,...

Université de Fribourg

The reinforcing influence of recommendations on global diversification

Zeng, An ; Yeung, Chi Ho ; Shang, Ming-Sheng ; Zhang, Yi-Cheng

In: Europhysics Letters - EPL, 2012, vol. 97, no. 1, p. 18005

Recommender systems are promising ways to filter the abundant information in modern society. Their algorithms help individuals to explore decent items, but it is unclear how they distribute popularity among items. In this paper, we simulate successive recommendations and measure their influence on the dispersion of item popularity by Gini coefficient. Our result indicates that local diffusion and...

Université de Fribourg

Behavior patterns of online users and the effect on information filtering

Zhang, Cheng-Jun ; Zeng, An

In: Physica A: Statistical Mechanics and its Applications, 2012, vol. 391, no. 4, p. 1822–1830

Understanding the structure and evolution of web-based user-item bipartite networks is an important task since they play a fundamental role in online information filtering. In this paper, we focus on investigating the patterns of online users’ behavior and the effect on recommendation process. Empirical analysis on the e-commercial systems show that users’ taste preferences are heterogeneous...

Université de Fribourg

Enhancing synchronization in growing networks

Wang, Yong-Li ; Zeng, An ; Di, Zengru ; Fan, Ying

In: Europhysics Letters - EPL, 2011, vol. 96, no. 55, p. 58007

Most real systems are growing. In order to model the evolution of real systems, many growing network models have been proposed to reproduce some specific topology properties. As the structure strongly influences the network function, designing the function-aimed growing strategy is also a significant task with many potential applications. In this letter, we focus on synchronization in the growing...

Université de Fribourg

Enhancing synchronization by directionality in complex networks

Zeng, An ; Son, Seung-Woo ; Yeung, Chi Ho ; Fan, Ying ; Di, Zengru

In: Physical Review E - Statistical, Nonlinear, and Soft Matter Physics, 2011, vol. 83, no. 4, p. 045101

We propose a method called the residual edge-betweenness gradient (REBG) to enhance the synchronizability of networks by assigning the link direction while keeping the topology and link weights unchanged. Direction assignment has been shown to improve the synchronizability of undirected networks in general, but we find that in some cases incommunicable components emerge and networks fail to...

Université de Fribourg

Dynamics on spatial networks and the effect of distance coarse graining

Zeng, An ; Zhou, Dong ; Hu, Yanqing ; Fan, Ying ; Di, Zengru

In: Physica A: Statistical Mechanics and its Applications, 2011, vol. 390, no. 21-22, p. 3962-3969

Recently, spatial networks have attracted much attention. The spatial network is constructed from a regular lattice by adding long-range edges (shortcuts) with probability P(r)∼r−δ, where r is the geographical distance between the two ends of the edge. Also, a cost constraint on the total length of the additional edges is introduced...

Université de Fribourg

Coarse graining for synchronization in directed networks

Zeng, An ; Lü, Linyuan

In: Physical Review E - statistical, non linear and soft matter physics, 2011, vol. 83, no. 5, p. 056123

Coarse-graining model is a promising way to analyze and visualize large-scale networks. The coarse-grained networks are required to preserve statistical properties as well as the dynamic behaviors of the initial networks. Some methods have been proposed and found effective in undirected networks, while the study on coarse-graining directed networks lacks of consideration. In this paper we...