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DY: Fachverband Dynamik und Statistische Physik
DY 6: Networks: From Topology to Dynamics I (joint session SOE / DY / BP)
DY 6.3: Talk
Monday, March 7, 2016, 10:30–10:45, H36
What does Big Data tell? Sampling the social network by communication channels — •János Török1,2, Yohsuke Murase3, Hang-Hyun Jo4,5, János Kertész2,1,5, and Kimmo Kaski5 — 1Department of Theoretical Physics, Budapest University of Technology and Economics, Budapest H-1111, Hungary — 2Center for Network Science, Central European University, Budapest H-1051, Hungary — 3RIKEN Advanced Institute for Computational Science, Kobe, Hyogo 650-0047, Japan — 4BK21plus Physics Division and Department of Physics, Pohang University of Science and Technology, Pohang 37673, Republic of Korea — 5Department of Computer Science, Aalto University School of Science, P.O. Box 15500, Espoo, Finland
Big Data has become the primary source of understanding the structure and dynamics of the society at large scale. However, usually one has information only about one of the channels, which should be considered as a sample of the whole. We show by simulations and analytical methods that this sampling may lead to bias. For example, while it is expected that the degree distribution of the whole social network has a maximum at a value larger than one, we get with reasonable assumptions about the sampling process a monotonously decreasing distribution as observed in empirical studies of single channel data. Also we find, that assortativity may occur or get strengthened due to the sampling process. We analyze the far-reaching consequences of our findings.