Figure 4

The verification of the model in three data sets. (a) Renren, the ground-truth value of the first 35 months’ population size (as points) and the estimated population size by the model (as dashed lines). (b) Twitter, the ground-truth value of the first 40 months’ population size (as points) and the estimated population size by the model (as dashed lines). (c) Gowalla, the ground-truth value of first 14 months’ population size (as points) and the estimated population size by the model (as dashed lines).