Fig. 4.

Network structure for the first 50 variables in ${\mathbf{X}}^{(1)}$ and ${\mathbf{X}}^{(2)}$. Left: scale-free network; Middle: Lattice; Right: Cluster. For the Scale-free network, we consider variable 2 has a hub variable. Variable 2 and the variables directly connected to it are considered as signal variables. For the Lattice network, all variables except variable 50 are considered as signals. For the Cluster network, the circled clusters are considered as signals