• A Hybrid Approach to Network Robustness Optimization using Edge Rewiring and Edge Addition

      Paterson, James; Department of Computer Science
      Networks are ubiquitous in the modern world. From computer and telecommunication networks to road networks and power grids, networks make up many crucial pieces of infrastructure that we interact with on a daily basis. These networks can be subjected to damage from many different sources, both random and targeted. If one of these networks receives too much damage, it may be rendered inoperable, which can have disastrous consequences. For this reason, it is in the best interests of those responsible for these networks to ensure that they are highly robust to failure. Since it is not usually feasible to rebuild most existing networks from scratch to make them more resilient, it is necessary to have an approach that can modify an existing network to make it more robust to failure. Previous work has established several methods of accomplishing this task, including edge rewiring and edge addition. Both of these methods can be very useful for optimizing network robustness, but each comes with its own set of limitations. This thesis proposes a new hybrid approach to network robustness optimization that combines both of these approaches. Four edge rewiring based metaheuristic approaches were modified to incorporate one of three different edge addition strategies. A comparative study was performed on these new hybrid optimizers, comparing them to each other and to the vanilla edge rewiring only approach on both synthetic and real world networks. Experiments showed that this new hybrid approach to network robustness optimization leads to much more highly robust networks than an edge rewiring only approach.