Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Long-Range Connections in Transportation Networks   Since its recent introduction, the small-world effect has been identified in
several important real-world systems. Frequently, it is a consequence of the
existence of a few long-range connections, which dominate the original regular
structure of the systems and implies each node to become accessible from other
nodes after a small number of steps, typically of order $\ell \propto \log N$.
However, this effect has been observed in pure-topological networks, where the
nodes have no spatial coordinates. In this paper, we present an alalogue of
small-world effect observed in real-world transportation networks, where the
nodes are embeded in a hree-dimensional space. Using the multidimensional
scaling method, we demonstrate how the addition of a few long-range connections
can suubstantially reduce the travel time in transportation systems. Also, we
investigated the importance of long-range connections when the systems are
under an attack process. Our findings are illustrated for two real-world
systems, namely the London urban network (streets and underground) and the US
highways network enhanced by some of the main US airlines routes.

18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
6
The categories of this paper are: astro-ph
5
The categories of this paper are: gr-qc