306,550 research outputs found
Robustness of a Network of Networks
Almost all network research has been focused on the properties of a single
network that does not interact and depends on other networks. In reality, many
real-world networks interact with other networks. Here we develop an analytical
framework for studying interacting networks and present an exact percolation
law for a network of interdependent networks. In particular, we find that
for Erd\H{o}s-R\'{e}nyi networks each of average degree , the giant
component, , is given by
where is the initial fraction of removed nodes. Our general result
coincides for with the known Erd\H{o}s-R\'{e}nyi second-order phase
transition for a single network. For any cascading failures occur
and the transition becomes a first-order percolation transition. The new law
for shows that percolation theory that is extensively studied in
physics and mathematics is a limiting case () of a more general general
and different percolation law for interdependent networks.Comment: 7 pages, 3 figure
On the influence of topological characteristics on robustness of complex networks
In this paper, we explore the relationship between the topological
characteristics of a complex network and its robustness to sustained targeted
attacks. Using synthesised scale-free, small-world and random networks, we look
at a number of network measures, including assortativity, modularity, average
path length, clustering coefficient, rich club profiles and scale-free exponent
(where applicable) of a network, and how each of these influence the robustness
of a network under targeted attacks. We use an established robustness
coefficient to measure topological robustness, and consider sustained targeted
attacks by order of node degree. With respect to scale-free networks, we show
that assortativity, modularity and average path length have a positive
correlation with network robustness, whereas clustering coefficient has a
negative correlation. We did not find any correlation between scale-free
exponent and robustness, or rich-club profiles and robustness. The robustness
of small-world networks on the other hand, show substantial positive
correlations with assortativity, modularity, clustering coefficient and average
path length. In comparison, the robustness of Erdos-Renyi random networks did
not have any significant correlation with any of the network properties
considered. A significant observation is that high clustering decreases
topological robustness in scale-free networks, yet it increases topological
robustness in small-world networks. Our results highlight the importance of
topological characteristics in influencing network robustness, and illustrate
design strategies network designers can use to increase the robustness of
scale-free and small-world networks under sustained targeted attacks
Robustness of Network of Networks with Interdependent and Interconnected links
Robustness of network of networks (NON) has been studied only for dependency
coupling (J.X. Gao et. al., Nature Physics, 2012) and only for connectivity
coupling (E.A. Leicht and R.M. D Souza, arxiv:0907.0894). The case of network
of n networks with both interdependent and interconnected links is more
complicated, and also more closely to real-life coupled network systems. Here
we develop a framework to study analytically and numerically the robustness of
this system. For the case of starlike network of n ER networks, we find that
the system undergoes from second order to first order phase transition as
coupling strength q increases. We find that increasing intra-connectivity links
or inter-connectivity links can increase the robustness of the system, while
the interdependency links decrease its robustness. Especially when q=1, we find
exact analytical solutions of the giant component and the first order
transition point. Understanding the robustness of network of networks with
interdependent and interconnected links is helpful to design resilient
infrastructures
Graph measures and network robustness
Network robustness research aims at finding a measure to quantify network
robustness. Once such a measure has been established, we will be able to
compare networks, to improve existing networks and to design new networks that
are able to continue to perform well when it is subject to failures or attacks.
In this paper we survey a large amount of robustness measures on simple,
undirected and unweighted graphs, in order to offer a tool for network
administrators to evaluate and improve the robustness of their network. The
measures discussed in this paper are based on the concepts of connectivity
(including reliability polynomials), distance, betweenness and clustering. Some
other measures are notions from spectral graph theory, more precisely, they are
functions of the Laplacian eigenvalues. In addition to surveying these graph
measures, the paper also contains a discussion of their functionality as a
measure for topological network robustness
ELASTICITY: Topological Characterization of Robustness in Complex Networks
Just as a herd of animals relies on its robust social structure to survive in
the wild, similarly robustness is a crucial characteristic for the survival of
a complex network under attack. The capacity to measure robustness in complex
networks defines the resolve of a network to maintain functionality in the
advent of classical component failures and at the onset of cryptic malicious
attacks. To date, robustness metrics are deficient and unfortunately the
following dilemmas exist: accurate models necessitate complex analysis while
conversely, simple models lack applicability to our definition of robustness.
In this paper, we define robustness and present a novel metric, elasticity- a
bridge between accuracy and complexity-a link in the chain of network
robustness. Additionally, we explore the performance of elasticity on Internet
topologies and online social networks, and articulate results
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