Figure I.

Four Main Types of Network. The top panel shows the network representations of the four main types, each consisting of 100 nodes. The middle panel shows the same networks in a circular layout to accentuate the differences between the network types. The bottom panel shows plots of two node centrality measures as well as the degree distribution for each of the above networks (all measurements are standardized). (A) Regular network: each node has exactly the same number of links. (B) Random network: nodes are randomly connected to each other. (C) Small-world network: most nodes can be reached from any other node through a short path. (D) Scale-free network: the degree distribution of nodes follows a power law.