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    Université de Fribourg

    Information filtering in sparse online systems: recommendation via semi-local diffusion

    Zeng, Wei ; Zeng, An ; Shang, Ming-Sheng ; Zhang, Yi-Cheng

    In: PLoS ONE, 2013, vol. 8, no. 11, p. e79354

    With the rapid growth of the Internet and overwhelming amount of information and choices that people are confronted with, recommender systems have been developed to effectively support users’ decision-making process in the online systems. However, many recommendation algorithms suffer from the data sparsity problem, i.e. the user-object bipartite networks are so sparse that algorithms cannot...

    Université de Fribourg

    Referee networks and their spectral properties

    Slanina, F. ; Zhang, Yi-Cheng

    In: Acta Physica Polonica B, 2005, vol. 36, no. 9, p. 2797-2804

    The bipartite graph connecting products and reviewers of that product is studied empirically in the case of We find that the network has power-law degree distribution on the side of reviewers, while on the side of products the distribution is better fitted by stretched exponential. The spectrum of normalised adjacency matrix shows power-law tail in the density of states....