  One of the challenges for future infrastructures is how to design a network
with high efficiency and strong connectivity at low cost. We propose
self-organized geographical networks beyond the vulnerable scale-free structure
found in many real systems. The networks with spatially concentrated nodes
emerge through link survival and path reinforcement on routing flows in a
wireless environment with a constant transmission range of a node. In
particular, we show that adding some shortcuts induces both the small-world
effect and a significant improvement of the robustness to the same level as in
the optimal bimodal networks. Such a simple universal mechanism will open
prospective ways for several applications in wide-area ad hoc networks, smart
grids, and urban planning.
