Scale-Free Download Network for Publications

The scale-free power-law behaviour of the statistics of the download frequency of publications has been reported, for the first time to our knowledge. The data of the download frequency of publications are taken from a well-constructed web page in the field of economic physics (http://www.unifr.ch/econophysics/). The Zipf-law analysis and the Tsallis entropy method were used to fit the download frequency. It was found that the power-law exponent of rank-ordered frequency distribution is γ～0.38±0.04, which is consistent with the power-law exponent α～3.37±0.45 for the cumulated frequency distributions. The preferential attachment model of Barabasi and Albert network has been used to explain the download network.