Research On Repair Strategies Of The Scale-free Networks

Along with the development of the network technology,the complex networks can be find anywhere at present.In the reality networks,the most common one is the scale-free networks.Because of the growth of the scale-free network itself,its topological structure has some special characters.In the scale-free networks,some nodes have very high degrees.They are the hub nodes of the networks.When some of these hub nodes break down or under attack,the connectivity of the networks would be destroyed badly.Nowadays,the most researches of the repair of the complex network are repairing the attacked nodes directly.However in reality,the attacked nodes couldn’t be repaired directly in some cases.For example: The important combat units in the military networks are destroyed;The bridges are dismantled or the traffic stations are closed in the traffic networks;The transformer stations breakdown and couldn’t be repaired quickly in the power grid networks and so on.In these cases,the repair strategies above couldn’t be used.To repair the networks in these situations,this thesis raises a repair strategy based on the compensation of the network links and builds different attack models aimed at the different attack strategies.In this thesis,the growing model of the scale-free network is built.The attack strategies are provided specifically.For the instantaneous attack,the neighbor nodes of the attacked nodes are repaired by the link compensation method.For 100 node network,the 80% of the survive nodes could be connected by repairing the 20% of the attacked nodes.When the amount of the repaired nodes rises to a enough high value,the survive nodes could be fully connected.Furthermore,for small size and large size networks,this kind of repair strategy is also effective.For the progressive attack,the suitable repair strategy is given in this thesis.The neighbor nodes of the attacked nodes are repaired by the link compensation method and the restrict parameters M and LCG are drawn in at the same time to make sure the scale-free character of the network not change.The simulation is done for a 200 node network and a 500 nodenetwork.Through the simulation,it can be proved that the network connectivity could be increased by this repair strategy.For a 200 node network the network connectivity could always be higher than 85% steadily during the growing of the scale-free networks.For a 500 node network,the connectivity could always be higher than 82% steadily through the progression of the network.In addition,through the double logarithmic coordinates figure of degree distribution,it can be reached that this kind of repair strategy could make sure that the scale-free character don’t change.And for both small size and large size networks,the repair strategy is effective.