  Interdependent networks have been shown to be extremely vulnerable based on
the percolation model. Parshani et. al further indicated that the more
inter-similar networks are, the more robust they are to random failure. Our
understanding of how coupling patterns shape and impact the cascading failures
of loads in interdependent networks is limited, but is essential for the design
and optimization of the real-world interdependent networked systems. This
question, however, is largely unexplored. In this paper, we address this
question by investigating the robustness of interdependent ER random graphs and
BA scale-free networks under both random failure and intentional attack. It is
found that interdependent ER random graphs are robust-yet-fragile under both
random failures and intentional attack. Interdependent BA scale-free networks,
however, are only robust-yet-fragile under random failure but fragile under
intentional attack. These results advance our understanding of the robustness
of interdependent networks significantly.
