共查询到20条相似文献,搜索用时 831 毫秒
1.
In this paper, we propose an evolving network model growing fast in units of module, according to the analysis of the evolution characteristics in real complex networks. Each module is a small-world network containing several interconnected nodes and the nodes between the modules are linked by preferential attachment on degree of nodes. We study the modularity measure of the proposed model, which can be adjusted by changing the ratio of the number of inner-module edges and the number of inter-module edges. In view of the mean-field theory, we develop an analytical function of the degree distribution, which is verified by a numerical example and indicates that the degree distribution shows characteristics of the small-world network and the scale-free network distinctly at different segments. The clustering coefficient and the average path length of the network are simulated numerically, indicating that the network shows the small-world property and is affected little by the randomness of the new module. 相似文献
2.
In this paper, we study the cascading failure in Watts-Strogatz small-world networks. We find that this network model has a heterogeneous betweenness distribution, although its degree distribution is homogeneous. Further study shows that this small-world network is robust to random attack but fragile to intentional attack, in the cascading failure scenario. With comparison to standard random graph and scale-free networks, our result indicates that the robust yet fragile property in the cascading failure scenario is mainly related to heterogeneous betweenness, rather than the network degree distribution. Thus, it suggests that we have to be very careful when we use terms such as homogeneous network and heterogeneous network, unless the distribution we refer to is specified. 相似文献
3.
《Physica A》2006,365(2):549-555
In this paper we present a model of immune system development when subjected to repeated infection events. The emergence of a complex network in shape space is outlined, the edges of which are characterised by both direction and weight. Such a network model supports a more comprehensive classification of immune function than was previously available in that the efficacy of infection elimination is directly dependent on both connectivity and weight distributions. The network model which emerges possesses both small-world characteristics, as well as a truncated scale-free degree and weight distribution commonly observed in social network models. 相似文献
4.
In many real-life networks, both the scale-free distribution of degree and small-world behavior are important features. There are many random or deterministic models of networks to simulate these features separately. However, there are few models that combine the scale-free effect and small-world behavior, especially in terms of deterministic versions. What is more, all the existing deterministic algorithms running in the iterative mode generate networks with only several discrete numbers of nodes. This contradicts the purpose of creating a deterministic network model on which we can simulate some dynamical processes as widely as possible. According to these facts, this paper proposes a deterministic network generation algorithm, which can not only generate deterministic networks following a scale-free distribution of degree and small-world behavior, but also produce networks with arbitrary number of nodes. Our scheme is based on a complete binary tree, and each newly generated leaf node is further linked to its full brother and one of its direct ancestors. Analytical computation and simulation results show that the average degree of such a proposed network is less than 5, the average clustering coefficient is high (larger than 0.5, even for a network of size 2 million) and the average shortest path length increases much more slowly than logarithmic growth for the majority of small-world network models. 相似文献
5.
Chunguang Li 《Physica A》2009,388(2-3):240-246
In this paper, we study the memory representation of morph patterns in an attractor neural network model. Since recent studies indicate that biological neural networks exhibit the so-called small-world effect, we study here how the small-world connection topology affects the dynamics of memory representation of morph patterns. We find that the small-world connection has significant effects on the memory representation dynamics in the network. Based on this finding, we postulate that global (or long-range) synaptic connections are mainly responsible for learning patterns that are significantly different from those already stored. Further numerical simulations show that the model based on this hypothesis has several advantages, for example fast learning and good performance. 相似文献
6.
《Physica A》2006,363(2):567-572
Small-world networks are ubiquitous in real-life systems. Most previous models of small-world networks are stochastic. The randomness makes it more difficult to gain a visual understanding on how do different nodes of networks interact with each other and is not appropriate for communication networks that have fixed interconnections. Here we present a model that generates a small-world network in a simple deterministic way. Our model has a discrete exponential degree distribution. We solve the main characteristics of the model. 相似文献
7.
The agent-based multileader model of the stock price dynamics on the directed evolving complex network is studied by direct
simulation. The resulting stationary regime follows from the balance of extremal dynamics, adaptivity of the strategic variables,
and reconnection rules. For given parametric combination, the network displays small-world phenomenon with high clustering
coefficients and power-law node degree distribution. The fitness exploration by the mechanism of repeated random walk is used
to violate dominance of centralized leadership. The simulation suggests that ultra slow dynamics of fitness implies explanation
of the long-time volatility of the log-price returns.
The text was submitted by the authors in English. 相似文献
8.
In this paper, we introduce a modified small-world network added with
new links with preferential connection instead of adding randomly,
then we apply Bak-Sneppen (BS) evolution model on this network.
Several dynamical character of the model such as the evolution
graph, f0 avalanche, the critical exponent D and τ, and
the distribution of mutation times of all the nodes, show
particular behaviors different from those of the model based on
the regular network and the small-world network. 相似文献
9.
Here, we constructed and analyzed a network (henceforth, “medical knowledge network”) derived from a commonly used medical text. We show that this medical knowledge network has small-world, scale-free, and hierarchical features. We then constructed a network from data from a hospital information system that reflected actual clinical practice and found that this network also had small-world, scale-free, and hierarchical features. Moreover, we found that both the diagnosis frequency distribution of the hospital network and the diagnosis degree distribution of the medical knowledge network obeyed a similar power law. These findings suggest that the structure of clinical practice may emerge from the mutual influence of medical knowledge and clinical practice, and that the analysis of a medical knowledge network may facilitate the investigation of the characteristics of medical practice. 相似文献
10.
We propose a deterministic weighted scale-free small-world model for considering pseudofractal web with the co-evolution of topology and weight. Considering the fluctuations in traffic flow constitute a main reason for congestion of packet delivery and poor performance of communication networks, we suggest a recursive algorithm to generate the network, which restricts the traffic fluctuations on it effectively during the evolutionary process. We provide a relatively complete view of topological structure and weight dynamics characteristics of the networks such as weight and strength distribution, degree correlations, average clustering coefficient and degree-cluster correlations as well as the diameter. 相似文献
11.
M. Medo J. Smrek 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,63(2):273-278
We investigate a network model based on an infinite regular
square lattice embedded in the Euclidean plane where the node
connection probability is given by the geometrical distance of
nodes. We show that the degree distribution in the basic model
is sharply peaked around its mean value. Since the model was
originally developed to mimic the social network of
acquaintances, to broaden the degree distribution we propose
its generalization. We show that when heterogeneity is
introduced to the model, it is possible to obtain fat tails of
the degree distribution. Meanwhile, the small-world phenomenon
present in the basic model is not affected. To support our
claims, both analytical and numerical results are obtained. 相似文献
12.
以电耦合的Terman-Wang小世界神经元网络系统为研究对象, 研究了空间关联白噪声影响下神经元网络系统的同步动力学. 首先将动力学平均场近似理论扩展到受空间关联白噪声影响下的小世界网络系统中, 将描述网络系统动力学演化的2N维随机微分方程简化为11个确定性的矩微分方程. 其次, 基于动力学平均场近似理论所推导的矩方程, 讨论了空间关联噪声、网络结构参数对神经元网络系统同步动力学的关键影响, 发现较大的噪声空间关联系数、耦合强度及节点平均度均对神经元网络系统同步放电具有积极作用. 进一步地, 利用计算机仿真数值模拟原神经元网络系统的同步动力学, 并与基于动力学平均场近似理论所得到的结果进行比较, 发现二者具有较好的一致性. 相似文献
13.
In this article, we propose an octahedral Koch network exhibiting abundant new properties compared to the triangular Koch network. Analytical expressions for the degree distribution, clustering coefficient, and average path length are presented. The scale-free feature and small-world property of the octahedral Koch network are obtained via numerical analysis. Furthermore, we show that the octahedral Koch network is assortative. Finally, we show that the projection of the octahedral Koch network on the plane is the nearest neighbor coupled Koch network, and the critical exponents of degree distribution in the octahedral Koch network is greater than three. 相似文献
14.
In this paper, we propose a simple model that can generate
small-world network with community structure. The network is
introduced as a tunable community organization with parameter r,
which is directly measured by the ratio of inter- to intra-community
connectivity, and a smaller r corresponds to a stronger community
structure. The structure properties, including the degree
distribution, clustering, the communication efficiency and
modularity are also analysed for the network. In addition, by using
the Kuramoto model, we investigated the phase synchronization on
this network, and found that increasing the fuzziness of community
structure will markedly enhance the network synchronizability;
however, in an abnormal region (r ≤ 0.001), the network has even
worse synchronizability than the case of isolated communities (r =
0). Furthermore, this network exhibits a remarkable
synchronization behaviour in topological scales: the oscillators of
high densely interconnected communities synchronize more easily, and
more rapidly than the whole network. 相似文献
15.
Yihong Hu 《Physica A》2009,388(10):2061-2071
In this paper we present an empirical study of the worldwide maritime transportation network (WMN) in which the nodes are ports and links are container liners connecting the ports. Using the different representations of network topology — the spaces L and P, we study the statistical properties of WMN including degree distribution, degree correlations, weight distribution, strength distribution, average shortest path length, line length distribution and centrality measures. We find that WMN is a small-world network with power law behavior. Important nodes are identified based on different centrality measures. Through analyzing weighted clustering coefficient and weighted average nearest neighbors degree, we reveal the hierarchy structure and rich-club phenomenon in the network. 相似文献
16.
17.
Many real-world systems can be modeled by weighted small-world networks with high clustering coefficients. Recent studies for rigorously analyzing the weighted spectral distribution(W SD) have focused on unweighted networks with low clustering coefficients. In this paper, we rigorously analyze the W SD in a deterministic weighted scale-free small-world network model and find that the W SD grows sublinearly with increasing network order(i.e., the number of nodes) and provides a sensitive discrimination for each input of this model. This study demonstrates that the scaling feature of the W SD exists in the weighted network model which has high and order-independent clustering coefficients and reasonable power-law exponents. 相似文献
18.
19.
《Physica A》2006,363(2):446-458
Empirical data of supermarket sales show stylised facts that are similar to stock markets, with a broad (truncated) Lévy distribution of weekly sales differences in the baseline sales [R.D. Groot, Physica A 353 (2005) 501]. To investigate the cause of this, the influence of social interactions and advertisements are studied in an agent-based model of consumers in a social network. The influence of network topology was varied by using a small-world network, a random network and a Barabási–Albert network. The degree to which consumers value the opinion of their peers was also varied.On a small-world and random network we find a phase transition between an open market and a locked-in market that is similar to condensation in liquids. At the critical point, fluctuations become large and buying behaviour is strongly correlated. However, on the small world network the noise distribution at the critical point is Gaussian, and critical slowing down occurs which is not observed in supermarket sales. On a scale-free network, the model shows a transition between a gas-like phase and a glassy state, but at the transition point the noise amplitude is much larger than what is seen in supermarket sales.To explore the role of advertisements, a model is studied where imprints are placed on the minds of consumers that ripen when a decision for a product is made. The correct distribution of weekly sales returns follows naturally from this model, as well as the noise amplitude, the correlation time and cross-correlation of sales fluctuations. For particular parameter values, simulated sales correlation shows power-law decay in time. The model predicts that social interaction helps to prevent aversion, and that products are viewed more positively when their consumption rate is higher. 相似文献
20.
Zhongzhi Zhang Shuigeng Zhou Lichao Chen 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(3):337-344
We present a family of scale-free network model consisting
of cliques, which is established by a simple recursive algorithm. We
investigate the networks both analytically and numerically. The
obtained analytical solutions show that the networks follow a
power-law degree distribution, with degree exponent continuously
tuned between 2 and 3. The exact expression of clustering
coefficient is also provided for the networks. Furthermore, the
investigation of the average path length reveals that the networks
possess small-world feature. Interestingly, we find that a special
case of our model can be mapped into the Yule process. 相似文献