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Université de Fribourg

Detecting community structure in complex networks via node similarity

Pan, Ying ; Li, De-Hua ; Liu, Jian-Guo ; Liang, Jing-Zhang

In: Physica A: Statistical Mechanics and its Applications, 2010, vol. 389, no. 14, p. 2849-2857

The detection of the community structure in networks is beneficial to understand the network structure and to analyze the network properties. Based on node similarity, a fast and efficient method for detecting community structure is proposed, which discovers the community structure by iteratively incorporating the community containing a node with the communities that contain the nodes with...

Université de Fribourg

Solving the apparent diversity-accuracy dilemma of recommender systems

Zhou, Tao ; Kuscsik, Zoltán ; Liu, Jian-Guo ; Medo, Matúš ; Wakeling, Joseph Rushton ; Zhang, Yi-Cheng

In: Proceedings of the National Academy of Sciences of the USA - PNAS, 2010, vol. 107, no. 10, p. 4511-4515

Recommender systems use data on past user preferences to predict possible future likes and interests. A key challenge is that while the most useful individual recommendations are to be found among diverse niche objects, the most reliably accurate results are obtained by methods that recommend objects based on user or object similarity. In this paper we introduce a new algorithm specifically to...

Université de Fribourg

Degree correlation of bipartite network on personalized recommendation

Liu, Jian-Guo ; Zhou, Tao ; Zhang, Yi-Cheng ; Guo, Qiang

In: International Journal of Modern Physics C, 2010, vol. 21, no. 1, p. 137-147

In this paper, the statistical property, namely degree correlation between users and objects, is taken into account and be embedded into the similarity index of collaborative filtering (CF) algorithm to improve the algorithmic performance. The numerical simulation on a benchmark data set shows that the algorithmic accuracy of the presented algorithm, measured by the average ranking score, is...

Université de Fribourg

Improved collaborative filtering algorithm via information transformation

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

In: International Journal of Modern Physics C, 2009, vol. 20, no. 2, p. 285-293

In this paper, we propose a spreading activation approach for collaborative filtering (SA-CF). By using the opinion spreading process, the similarity between any users can be obtained. The algorithm has remarkably higher accuracy than the standard collaborative filtering using the Pearson correlation. Furthermore, we introduce a free parameter β to regulate the contributions of objects to...

Université de Fribourg

Effects of user's tastes on personalized recommendation

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

In: International Journal of Modern Physics C, 2009, vol. 20, no. 12, p. 1925-1932

In this paper, based on a weighted projection of the user-object bipartite network, we study the effects of user tastes on the mass-diffusion-based personalized recommendation algorithm, where a user's tastes or interests are defined by the average degree of the objects he has collected. We argue that the initial recommendation power located on the objects should be determined by both of their...

Université de Fribourg

Effects of high-order correlations on personalized recommendations for bipartite networks

Liu, Jian-Guo ; Zhou, Tao ; Che, Hong-An ; Wang, Bing-Hong ; Zhang, Yi-Cheng

In: Physica A, 2010, vol. 389, no. 4, p. 881-886

In this paper, we introduce a modified collaborative filtering (MCF) algorithm, which has remarkably higher accuracy than the standard collaborative filtering. In the MCF, instead of the cosine similarity index, the user–user correlations are obtained by a diffusion process. Furthermore, by considering the second-order correlations, we design an effective algorithm that depresses the influence...

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

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

Empirical analysis on a keyword-based semantic system

Zhang, Zi-Ke ; Lü, Linyuan ; Liu, Jian-Guo ; Zhou, Tao

In: The European Physical Journal B, 2008, vol. 66, no. 4, p. 557-561

Keywords in scientific articles have found their significance in information filtering and classification. In this article, we empirically investigated statistical characteristics and evolutionary properties of keywords in a very famous journal, namely Proceedings of the National Academy of Science of the United States of America (PNAS), including frequency distribution, temporal scaling...

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...