Figure 1. Relationships between the distribution of source (N_src), sink (N_snk) and conduit (N_cdt) nodes and the network control profile parameters among 98 empirical networks.

Networks with maximal control profile parameters of η_s, η_e, and η_i are respectively drawn with black squares, red circles, and green triangles. Black lines are drawn through the origin with a slope of 1 as a visual reference. (a) Each source node must be directly controlled, but networks with the largest values of η_s are not necessarily those with the largest relative fraction of source nodes. (b) In cases where the number of sink nodes greatly outweighs the number of source nodes, η_e is unambiguously the dominant control profile parameter; while sufficient, this is not necessary for a network to have a high value of η_e. (c) Networks with high values of η_i are generally dominated by conduit nodes, but the converse does not hold.