Wang et al. (2013) also pointed out that it is reasonable to regard the time points with the highest expression value of a protein as the active time points, and the time points with expression values near to the highest one can also be considered as active time points since small differences are allowable and noise exists in data. Basing on that, we construct the dynamic PPI network in the following way, and the effects of different thresholds on several characteristics of the dynamic network will be introduced in Section 3.2.