Figure 1: The illustration of various strategic repair processes after localised attack (LA) on two-dimensional square lattice with heterogeneously populated nodes.
From: Recovery of infrastructure networks after localised attacks
The attack center is randomly selected. (A) The schematic localised attack. The attack intensity will decline with distance from the attack center. An edge is disrupted only if the attack intensity is larger than a threshold. The distance between two edges is defined as the vertical distance from the mid-point of one edge to other edge. The darkest gray area suffers the largest attack intensity, and the lightest gray area suffers the smallest attack intensity which is lower than the physical disruption threshold of edge. Only the edges coloured red, blue and yellow fail. In this case, a group of geographically localised edges fail and are removed from the network. (B) The remaining functional edges after localised attack, and the yellow nodes are isolated. (C1–C3) The operations of PR. In (C1) the blue edges with arrowhead are the damaged edges adjacent to the functional components of the network. The red node n1 is the node adjacent to the network with the largest population, and either edge m1 or m2 will be repaired first randomly. In this case, m1 is selected to be restored first and coloured green. After all the isolated nodes are connected at last, m2 will be repaired coloured yellow. At the next step, the node n2 in (C2) is the node adjacent to the functional network and with the largest population, and either edges m3 or m4 will be repaired randomly. The process will be iterated until all the isolated nodes are connected to the functional network, as shown in (C3). At last, the yellow edges will be repaired randomly one by one until all are repaired. (D1–D4) The operation of PRNW. In (D1) the red node n3 has the largest population among all the isolated nodes, and edge m5 connects n3 to the network. The edge m5 will be repaired first and coloured green. In the next step, n5 is the most populated node; the edges m6 and m7 which connect n5 to the functional network, will be repaired one after the other. The procedures are iterated until all the isolated nodes are connected to the network, as shown in (D4). At last, the yellow edges will be repaired randomly one by one until the all edges are repaired.
