Fig. 1.

The two network intervention strategies (dividing groups and balancing groups). The flow is A → B, A → C, A → D, and C → E. We display a hypothetical network of eight people across two sectors (groups X and Y are in the same sector, and groups S and T are in the same sector). In the simulation, we used a network of 10,000 people across eight sectors. The two-mode networks (Top) show the distribution of group activities and sectors in which each subject (IDs 1 to 8) participates. For example, ID1 belongs to X₀ (e.g., go to workplace X₀) and T₀ (e.g., go to supermarket T₀) and regularly engages in his or her activities (e.g., working and shopping, respectively) at the appropriate locations (X₀ and T₀). The two-mode networks can be converted to one-mode networks (Bottom), in which a shared group connects two individuals. For example, ID1 and ID2 may be involved in transmission at X₀ and the network tie between ID1 and ID2. A network tie in one-mode networks represents a chance of transmission, while an arrow in two-mode networks represents an individual going to a location and engaging in economic activities. In this example, the mean degree (number of the network ties per individual) and its variation (SD) are smaller when dividing groups (A → C) and balancing groups (A → D).