共查询到20条相似文献,搜索用时 15 毫秒
1.
J. F. Donges Y. Zou N. Marwan J. Kurths 《The European physical journal. Special topics》2009,174(1):157-179
Complex network theory provides a powerful framework to statistically investigate the topology of local and non-local statistical
interrelationships, i.e. teleconnections, in the climate system. Climate networks constructed from the same global climatological
data set using the linear Pearson correlation coefficient or the nonlinear mutual information as a measure of dynamical similarity
between regions, are compared systematically on local, mesoscopic and global topological scales. A high degree of similarity
is observed on the local and mesoscopic topological scales for surface air temperature fields taken from AOGCM and reanalysis
data sets. We find larger differences on the global scale, particularly in the betweenness centrality field. The global scale
view on climate networks obtained using mutual information offers promising new perspectives for detecting network structures
based on nonlinear physical processes in the climate system. 相似文献
2.
M. S. Baptista S. P. Garcia S. K. Dana J. Kurths 《The European physical journal. Special topics》2008,165(1):119-128
We propose a rationale for experimentally studying the intricate relationship between the rate of information transmission
and synchronization level in active networks, applying theoretical results recently proposed. We consider two non-identical
coupled Chua’s circuit with non-identical coupling strengths in order to illustrate the proceeding for experimental scenarios
of very few data points coming from highly non-coherent coupled systems, such that phase synchronization can only be detected
by methods that do not rely explicitely on the calculation of the phase. A relevant finding is to show that for the coupled
Chua’s circuit, the larger the level of synchronization the larger the rate of information exchanged between both circuits.
We further validate our findings with data from numerical simulations, and discuss an extension to arbitrarily large active
networks. 相似文献
3.
The complex network theory is a way to investigate the complex systems with minimum
information about their entities and corresponding interactions. There is a growing
interest to studying the earthquake phenomena by the method of networks. Several network
features characterize the complexity of seismic events. Unfortunately they depend on how
we construct the network. Here we study the role of cell size or in other word the
resolution on the network properties for the Iran’s seismic data. We have found that all
the network topological features vary as a power of the resolution. Furthermore by
increasing the resolution, the networks become random and uncorrelated. 相似文献
4.
Enhancing the network synchronizability 总被引:1,自引:0,他引:1
The structural and dynamical properties, particularly the small-world effect and scale-free feature, of complex networks have
attracted tremendous interest and attention in recent years. This article offers a brief review of one focal issue concerning
the structural and dynamical behaviors of complex network synchronization. In the presentation, the notions of synchronization
of dynamical systems on networks, stability of dynamical networks, and relationships between network structure and synchronizability,
will be first introduced. Then, various technical methods for enhancing the network synchronizability will be discussed, which
are roughly divided into two classes: Structural Modification and Coupling-Pattern Regulation, where the former includes three
typical methods—dividing hub nodes, shortening average distances, and deleting overload edges, while the latter mainly is
a method of strengthening the hub-nodes’ influence on the network.
相似文献
5.
Piotr J. Górski Agnieszka Czaplicka Janusz A. Hołyst 《The European Physical Journal B - Condensed Matter and Complex Systems》2016,89(2):33
Random Boolean Networks (RBNs) are frequently used for modeling complex systems driven by information processing, e.g. for gene regulatory networks (GRNs). Here we propose a hierarchical adaptive random Boolean Network (HARBN) as a system consisting of distinct adaptive RBNs (ARBNs) – subnetworks – connected by a set of permanent interlinks. We investigate mean node information, mean edge information as well as mean node degree. Information measures and internal subnetworks topology of HARBN coevolve and reach steady-states that are specific for a given network structure. The main natural feature of ARBNs, i.e. their adaptability, is preserved in HARBNs and they evolve towards critical configurations which is documented by power law distributions of network attractor lengths. The mean information processed by a single node or a single link increases with the number of interlinks added to the system. The mean length of network attractors and the mean steady-state connectivity possess minima for certain specific values of the quotient between the density of interlinks and the density of all links in networks. It means that the modular network displays extremal values of its observables when subnetworks are connected with a density a few times lower than a mean density of all links. 相似文献
6.
We study a generalization of the voter model on complex networks, focusing on the scaling of mean exit time. Previous work
has defined the voter model in terms of an initially chosen node and a randomly chosen neighbor, which makes it difficult
to disentangle the effects of the stochastic process itself relative to the network structure. We introduce a process with
two steps, one that selects a pair of interacting nodes and one that determines the direction of interaction as a function
of the degrees of the two nodes and a parameter α which sets the likelihood of the higher degree node giving its state to the other node. Traditional voter model behaviors
can be recovered within the model, as well as the invasion process. We find that on a complete bipartite network, the voter
model is the fastest process. On a random network with power law degree distribution, we observe two regimes. For modest values
of α, exit time is dominated by diffusive drift of the system state, but as the high-degree nodes become more influential, the
exit time becomes dominated by frustration effects dependent on the exact topology of the network. 相似文献
7.
V. I. Ermakov V. P. Okhlopkov Yu. I. Stozhkov 《Moscow University Physics Bulletin》2009,64(2):214-217
Flows of material particles, viz., cosmic rays and cosmic dust, are perpetually coming from space into the Earth’s atmosphere;
these are particles sized from 0.001 μm to dozens or hundreds of μm. The paper shows that cosmic rays influence the main parameters
of the atmosphere’s electricity, and cosmic dust influences global cloudiness, albedo and the Earth’s climate.
Original Russian Text ? V.I. Ermakov, V.P. Okhlopkov, Yu.I. Stozhkov, 2009, published in Vestnik Moskovskogo Universiteta.
Fizika, 2009, No. 2, pp. 104–106. 相似文献
8.
Proteins are important biomolecules, which perform diverse structural and functional roles in living systems. Starting from
a linear chain of amino acids, proteins fold to different secondary structures, which then fold through short- and long-range
interactions to give rise to the final three-dimensional shapes useful to carry out the biophysical and biochemical functions.
Proteins are defined as having a common ‘fold’ if they have major secondary structural elements with same topological connections.
It is known that folding mechanisms are largely determined by a protein’s topology rather than its interatomic interactions.
The native state protein structures can, thus, be modelled, using a graph-theoretical approach, as coarse-grained networks
of amino acid residues as ‘nodes’ and the inter-residue interactions/contacts as ‘links’. Using the network representation
of protein structures and their 2D contact maps, we have identified the conserved contact patterns (groups of contacts) representing
two typical folds — the EF-hand and the ubiquitin-like folds. Our results suggest that this direct and computationally simple
methodology can be used to infer about the presence of specific folds from the protein’s contact map alone.
相似文献
9.
The collective dynamics of coupled two-dimensional chaotic maps on complex networks is known to exhibit a rich variety of emergent properties which crucially depend on the underlying network topology. We investigate the collective motion of Chirikov standard maps interacting with time delay through directed links of gene regulatory network of bacterium Escherichia coli. Departures from strongly chaotic behavior of the isolated maps are studied in relation to different coupling forms and strengths. At smaller coupling intensities the network induces stable and coherent emergent dynamics. The unstable behavior appearing with increase of coupling strength remains confined within a connected subnetwork. For the appropriate coupling, network exhibits statistically robust self-organized dynamics in a weakly chaotic regime. 相似文献
10.
We study the totally asymmetric simple exclusion process (TASEP) on complex networks, as a paradigmatic model for transport subject to excluded volume interactions. Building on TASEP phenomenology on a single segment and borrowing ideas from random networks we investigate the effect of connectivity on transport. In particular, we argue that the presence of disorder in the topology of vertices crucially modifies the transport features of a network: irregular networks involve homogeneous segments and have a bimodal distribution of edge densities, whereas regular networks are dominated by shocks leading to a unimodal density distribution. The proposed numerical approach of solving for mean-field transport on networks provides a general framework for studying TASEP on large networks, and is expected to generalize to other transport processes. 相似文献
11.
Jan H. Feldhoff Reik V. Donner Jonathan F. Donges Norbert Marwan Jürgen Kurths 《Physics letters. A》2012
We introduce a geometric method for identifying the coupling direction between two dynamical systems based on a bivariate extension of recurrence network analysis. Global characteristics of the resulting inter-system recurrence networks provide a correct discrimination for weakly coupled Rössler oscillators not yet displaying generalised synchronisation. Investigating two real-world palaeoclimate time series representing the variability of the Asian monsoon over the last 10,000 years, we observe indications for a considerable influence of the Indian summer monsoon on climate in Eastern China rather than vice versa. The proposed approach can be directly extended to studying K>2 coupled subsystems. 相似文献
12.
How do diverse dynamical patterns arise from the topology of complex networks? We study synchronization dynamics in the cortical brain network of the cat, which displays a hierarchically clustered organization, by modeling each node (cortical area) with a subnetwork of interacting excitable neurons. We find that in the biologically plausible regime the dynamics exhibits a hierarchical modular organization, in particular, revealing functional clusters coinciding with the anatomical communities at different scales. Our results provide insights into the relationship between network topology and functional organization of complex brain networks. 相似文献
13.
Many realistic networks live in the form of multiple networks, including interacting networks and interdependent networks. Here we study percolation properties of a special kind of interacting networks, namely Shopping and Cashback Electronic Commerce Networks (SCECNs). We investigate two actual SCECNs to extract their structural properties, and develop a mathematical framework based on generating functions for analyzing directed interacting networks. Then we derive the necessary and sufficient condition for the absence of the system-wide giant in- and out- component, and propose arithmetic to calculate the corresponding structural measures in the sub-critical and supercritical regimes. We apply our mathematical framework and arithmetic to those two actual SCECNs to observe its accuracy, and give some explanations on the discrepancies. We show those structural measures based on our mathematical framework and arithmetic are useful to appraise the status of SCECNs. We also find that the supercritical regime of the whole network is maintained mainly by hyperlinks between different kinds of websites, while those hyperlinks between the same kinds of websites can only enlarge the sizes of in-components and out-components. 相似文献
14.
M. Chavez D.-U. Hwang S. Boccaletti 《The European physical journal. Special topics》2007,146(1):129-144
During the last decades the emergence of collective
dynamics in large networks of coupled units has been investigated
in fields such as optics, chemistry, biology and ecology.
Recently, complex networks have provided a challenging framework
for the study of synchronization of dynamical units, based on the
interplay between complexity in the overall topology and local
dynamical properties of the coupled units. In this work, we review
the constructive role played by such complex wirings for the
synchronization of networks of coupled dynamical systems. We
review the main techniques that have been proposed for assessing
the propensity for synchronization (synchronizability) of a given
networked system. We will also describe the main applications,
especially in the view of selecting the optimal topology in the
coupling configuration that provides enhancement of the
synchronization features. 相似文献
15.
This Letter investigates synchronization issues of complex dynamical networks with switching topology. By constructing a common Lyapunov function, we show that local and global synchronization for a linearly coupled network with switching topology can be evaluated by the time average of second smallest eigenvalues corresponding to the Laplacians of switching topology. This result is quite powerful and can be further used to explore various switching cases for complex dynamical networks. Numerical simulations illustrate the effectiveness of the obtained results in the end. 相似文献
16.
《Physics letters. A》2014,378(18-19):1239-1248
Synchronization is one of the most important features observed in large-scale complex networks of interacting dynamical systems. As is well known, there is a close relation between the network topology and the network synchronizability. Using the coupled Hindmarsh–Rose neurons with community structure as a model network, in this paper we explore how failures of the nodes due to random errors or intentional attacks affect the synchronizability of community networks. The intentional attacks are realized by removing a fraction of the nodes with high values in some centrality measure such as the centralities of degree, eigenvector, betweenness and closeness. According to the master stability function method, we employ the algebraic connectivity of the considered community network as an indicator to examine the network synchronizability. Numerical evidences show that the node failure strategy based on the betweenness centrality has the most influence on the synchronizability of community networks. With this node failure strategy for a given network with a fixed number of communities, we find that the larger the degree of communities, the worse the network synchronizability; however, for a given network with a fixed degree of communities, we observe that the more the number of communities, the better the network synchronizability. 相似文献
17.
With remarkable advances in reconstruction of genome-scale metabolic networks, uncovering complex network structure and function from these networks is becoming one of the most important topics in system biology. This work aims at studying the structure and function of Staphylococcus aureus (S. aureus) metabolic network by complex network methods. We first generated a metabolite graph from the recently reconstructed high-quality S. aureus metabolic network model. Then, based on ‘bow tie’ structure character, we explain and discuss the global structure of S. aureus metabolic network. The functional significance, global structural properties, modularity and centrality analysis of giant strong component in S. aureus metabolic networks are studied. 相似文献
18.
Annick Lesne 《Letters in Mathematical Physics》2006,78(3):235-262
The aim of this text is to show the central role played by networks in complex system science. A remarkable feature of network studies is to lie at the crossroads of different disciplines, from mathematics (graph theory, combinatorics, probability theory) to physics (statistical physics of networks) to computer science (network generating algorithms, combinatorial optimization) to biological issues (regulatory networks). New paradigms recently appeared, like that of ‘scale-free networks’ providing an alternative to the random graph model introduced long ago by Erdös and Renyi. With the notion of statistical ensemble and methods originally introduced for percolation networks, statistical physics is of high relevance to get a deep account of topological and statistical properties of a network. Then their consequences on the dynamics taking place in the network should be investigated. Impact of network theory is huge in all natural sciences, especially in biology with gene networks, metabolic networks, neural networks or food webs. I illustrate this brief overview with a recent work on the influence of network topology on the dynamics of coupled excitable units, and the insights it provides about network emerging features, robustness of network behaviors, and the notion of static or dynamic motif. 相似文献
19.
We review our recent work on the synchronization of a network of delay-coupled maps, focusing on the interplay of the network
topology and the delay times that take into account the finite velocity of propagation of interactions. We assume that the
elements of the network are identical (N logistic maps in the regime where the individual maps, without coupling, evolve in a chaotic orbit) and that the coupling
strengths are uniform throughout the network. We show that if the delay times are sufficiently heterogeneous, for adequate
coupling strength the network synchronizes in a spatially homogeneous steady state, which is unstable for the individual maps
without coupling. This synchronization behavior is referred to as ‘suppression of chaos by random delays’ and is in contrast
with the synchronization when all the interaction delay times are homogeneous, because with homogeneous delays the network
synchronizes in a state where the elements display in-phase time-periodic or chaotic oscillations. We analyze the influence
of the network topology considering four different types of networks: two regular (a ring-type and a ring-type with a central
node) and two random (free-scale Barabasi-Albert and small-world Newman-Watts). We find that when the delay times are sufficiently
heterogeneous the synchronization behavior is largely independent of the network topology but depends on the network’s connectivity,
i.e., on the average number of neighbors per node.
相似文献
20.
By using the tools of statistical physics and recent investigations of the scaling properties of different complex networks,
the structural and evolving properties of the Chinese railway network (CRN) is studied. It has been verified that the CRN
has the same small-world properties of the Indian railway network (IRN). According to the class of small-world networks, we
believe the CRN is a single scale. In addition, a novel result is obtained. Measurements on the CRN indicate that the rate
at which nodes acquire links depends on the node’s degree and follows a power law.
相似文献