Modelling scale-free networks
The Internet has grown faster and larger than ever expected. Efforts have been made to quantify the Internet, to map it and to model it. The challenge is that the Internet is a complex network, more specifically a scale-free network that continues to expand every day. The Future and Emerging Technologies (FET) branch of the Information Society Technologies (IST) Programme funded the COSIN consortium to develop new models for scale-free networks. The Ecole Polytechnique Fédérale de Lausanne (EPFL) worked on several different models, performing sensitivity tests to determine which model best reproduced what is observed in the real world. When it comes to the Internet, part of the problem is that it cannot be accurately described. This is because the tools used to measure the Internet are themselves not perfect. The EPFL addressed this issue by parameterising important network mechanisms, encompassing technological, economical and political aspects. One model developed by the EPFL was particularly successful with respect to illustrating node interaction. As with all the models developed during COSIN, its relevance extends well beyond the Internet. Scale-free networks also exist within biology, specifically protein interactions, as well as in the fields of economics and the social sciences. The EPFL stresses, however, that further research is necessary to determine exactly how suitable the new models are for such applications. Furthermore, they aim to resolve problems which derive from incomplete understanding of microscopic features of scale-free networks.
