Stable community cores in complex networks

Massoud Seifi, Jean-Loup Guillaume, Ivan Junier, Jean-Baptiste Rouquier and Svilen Iskrov

Proceedings of the 3rd Workshop on Complex Networks (CompleNet 2012), Melbourne, Florida

Complex networks are generally composed of dense sub-networks called communities. Many algorithms have been proposed to automatically detect such communities. However, they are often unstable and behave non-deterministically. We propose here to use this non-determinism in order to compute groups of nodes on which community detection algorithms agree most of the time.We show that these groups of nodes, called community cores, are more similar to Ground Truth than communities in real and artificial networks. Furthermore, we show that in contrary to the classical approaches, we can reveal the absence of community structure in random graphs.

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A Real-World Spreading Experiment in the Blogosphere

Adrien Friggeri, Jean-Philippe Cointet and Matthieu Latapy

Complex Systems 19, 2011

We designed an experiment to observe a spreading phenomenon in the blogosphere. This experiment relies on a small applet that participants copy on their own web page. We present the obtained dataset, which we freely provide for study, and conduct basic analysis. We conclude that, despite the classical assumption, in this experiment famous blogs do not necessarily act as super spreaders.

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