Before revision: We propose a dynamic hidden-variable model to formally define the two dynamical classes , with which we show that the global fluctuations in a real-world dynamical system can be explained by either of the two simple mechanisms. Our findings will contribute to a better understanding of the origin of the time-varying nature of complex networks .
After revision: We propose a dynamic hidden-variable model to formally define the two dynamical classes . The model is fitted to the time-varying nature of complex networks .