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1.
凌翔  胡茂彬  龙建成  丁建勋  石琴 《中国物理 B》2013,22(1):18904-018904
In this paper, an optimal resource allocation strategy is proposed to enhance traffic dynamics in complex networks. The network resources are the total node packet-delivering capacity and the total link bandwidth. An analytical method is developed to estimate the overall network capacity by using the concept of efficient betweenness (ratio of algorithmic betweenness and local processing capacity). Three network structures (scale-free, small-world, and random networks) and two typical routing protocols (shortest path protocol and efficient routing protocol) are adopted to demonstrate the performance of the proposed strategy. Our results show that the network capacity is reversely proportional to the average path length for a particular routing protocol and the shortest path protocol can achieve the largest network capacity when the proposed resource allocation strategy is adopted.  相似文献   

2.
刘锋  赵寒  李明  任丰原  朱衍波 《中国物理 B》2010,19(4):40513-040513
Due to the heterogeneity of the structure on a scale-free network,making the betweennesses of all nodes become homogeneous by reassigning the weights of nodes or edges is very difficult.In order to take advantage of the important effect of high degree nodes on the shortest path communication and preferentially deliver packets by them to increase the probability to destination,an adaptive local routing strategy on a scale-free network is proposed,in which the node adjusts the forwarding probability with the dynamical traffic load(packet queue length) and the degree distribution of neighbouring nodes.The critical queue length of a node is set to be proportional to its degree,and the node with high degree has a larger critical queue length to store and forward more packets.When the queue length of a high degree node is shorter than its critical queue length,it has a higher probability to forward packets.After higher degree nodes are saturated(whose queue lengths are longer than their critical queue lengths),more packets will be delivered by the lower degree nodes around them.The adaptive local routing strategy increases the probability of a packet finding its destination quickly,and improves the transmission capacity on the scale-free network by reducing routing hops.The simulation results show that the transmission capacity of the adaptive local routing strategy is larger than that of three previous local routing strategies.  相似文献   

3.
For further research on the gravity mechanism of the routing protocol in complex networks,we introduce the concept of routing awareness depth,which is represented by ρ.On this basis,we define the calculation formula of the gravity of the transmission route for the packet,and propose a routing strategy based on the gravitational field of the node and the routing awareness depth.In order to characterize the efficiency of the method,we introduce an order parameter,η,to measure the throughput of the network by the critical value of phase transition from free flow to congestion,and use the node betweenness centrality,B,to test the transmission efficiency of the network and congestion distribution.We simulate the network transmission performance under different values of the routing awareness depth,ρ.Simulation results show that if the value of the routing awareness depth ρ is too small,then the gravity of the route is composed of the attraction of very few nodes on the route,which cannot improve the capacity of the network effectively.If the value of the routing awareness depth ρ is greater than the network's average distance l,then the capacity of the network may be improved greatly and no longer change with the sustainable increment of routing awareness depth ρ,and the routing strategy performance enters into a constant state.Moreover,whatever the value of the routing awareness depth ρ,our algorithm always effectively balances the distribution of the betweenness centrality and realizes equal distribution of the network load.  相似文献   

4.
As a special quantum node in a quantum network, the quantum router plays an important role in storing and transferring quantum information. In this paper, we propose a quantum router scheme based on asymmetric intercavity couplings and a three-level Λ-type atomic system. This scheme implements the quantum routing capability very well. It can perfectly transfer quantum information from one quantum channel to another. Compared with the previous quantum routing scheme, our proposed scheme can achieve the transfer rate of single photons from one quantum channel to another quantum channel reaching 100%, the high transfer rate is located in the almost quadrant regions with negative values of the two variables λ_a and λ_b, and their maximum values T_u~b+T_d~b= 1 emerge in the center point λ_a=λ_b=-1. Therefore, it is possibly feasible to efficiently enhance the routing capability of the single photons between two channels by adjusting the inter-resonator couplings, and the asymmetric intercavity coupling provides a new method for achieving high-fidelity quantum routers.  相似文献   

5.
A domain-level gradient-based routing (DLR) algorithm for heterogeneous optical networks with syn- chronous digital hierarchy and optical transport network domains is proposed and experimentally vali- dated. This algorithm classifies domains into groups with incremental levels on the basis of domain-level partitioning, and guides paths level by level along a gradient on the basis of interdomain routing tree evolution. The proposed algorithm is implemented in the hierarchical path computation element-based control architecture for connection provisioning. Testbeds with commercial and emulated nodes are es- tablished to verify the feasibility and performance of the algorithm. Experimental and emulation results show that DLR effectively performs in terms of network blocking probability, real time characteristics, and scalability.  相似文献   

6.
沈毅  裴文江  王开  王少平 《中国物理 B》2009,18(9):3783-3789
The shortcomings of traditional methods to find the shortest path are revealed,and a strategy of finding the selforganizing shortest path based on thermal flux diffusion on complex networks is presented.In our method,the shortest paths between the source node and the other nodes are found to be self-organized by comparing node temperatures.The computation complexity of the method scales linearly with the number of edges on underlying networks.The effects of the method on several networks,including a regular network proposed by Ravasz and Baraba’si which is called the RB network,a real network,a random network proposed by Ravasz and Baraba’si which is called the ER network and a scale-free network,are also demonstrated.Analytic and simulation results show that the method has a higher accuracy and lower computational complexity than the conventional methods.  相似文献   

7.
李忠奎  段志生  陈关荣 《中国物理 B》2009,18(12):5228-5234
This paper concerns the disturbance rejection problem of a linear complex dynamical network subject to external disturbances.A dynamical network is said to be robust to disturbance,if the H ∞ norm of its transfer function matrix from the disturbance to the performance variable is satisfactorily small.It is shown that the disturbance rejection problem of a dynamical network can be solved by analysing the H ∞ control problem of a set of independent systems whose dimensions are equal to that of a single node.A counter-intuitive result is that the disturbance rejection level of the whole network with a diffusive coupling will never be better than that of an isolated node.To improve this,local feedback injections are applied to a small fraction of the nodes in the network.Some criteria for possible performance improvement are derived in terms of linear matrix inequalities.It is further demonstrated via a simulation example that one can indeed improve the disturbance rejection level of the network by pinning the nodes with higher degrees than pinning those with lower degrees.  相似文献   

8.
朱俊  何广强  曾贵华 《中国物理》2007,16(5):1364-1369
In this paper security of the quantum key distribution scheme using correlations of continuous variable Einstein- Podolsky-Rosen (EPR) pairs is investigated. A new approach for calculating the secret information rate △I is proposed by using the Shannon information theory. Employing an available parameter F which is associated with the entanglement of the EPR pairs, one can detect easily the eavesdropping. Results show that the proposed scheme is secure against individual bearn splitter attack strategy with a proper squeeze parameter.  相似文献   

9.
The performance of an optical switching network is mainly determined by its core node structure. An improved optical packet switching (OPS) node structure based on recirculation optical fiber delay line (FDL) and feedback tunable wavelength converter (TWC), and a specific scheduling algorithm for the node structure are presented. This switching structure supports both point-to-point and point-to-multi- points broadcasting transmission with superior capacity expansion performance. Its superiority in packet loss probability is proved by simulation.  相似文献   

10.
This paper is concerned with the robust Hoo synchronization problem for a class of complex dynamical networks by applying the observer-based control. The proposed feedback control scheme is developed to ensure the asymptotic stability of the augmented system, to reconstruct the non-measurable state variables of each node and to improve the H∞ performance related to the synchronization error and observation error despite the external disturbance. Based on the Lyapunov stability theory, a synchronization criterion is obtained under which the controlled network can be robustly stabilized onto a desired state with a guaranteed H∞ performance. The controller and the observer gains can be given by the feasible solutions of a set of linear matrix inequalities (LMIs). The effectiveness of the proposed control scheme is demonstrated by a numerical example through simulation.  相似文献   

11.
无标度复杂网络负载传输优化策略   总被引:4,自引:0,他引:4       下载免费PDF全文
李涛  裴文江  王少平 《物理学报》2009,58(9):5903-5910
提出了一种能够显著提高无标度复杂网络负载传输性能的优化路由策略.实现了负载在核心节点与边缘节点间的合理分配.分析表明该策略使得网络的负载处理能力正比于网络规模的平方,而与单个节点的度值无关.实验结果显示优化路由策略在保持了最短路由策略小世界效应的同时,成倍地提升了网络的负载传输能力,且随着网络平均节点度的增加其优势越趋显著.此外,与有效路由策略的比较进一步验证了优化路由策略的优异性能. 关键词: 优化路由策略 复杂网络 负载传输 网络阻塞  相似文献   

12.
王开  周思源  张毅锋  裴文江  刘茜 《物理学报》2011,60(11):118903-118903
在对随机行走过程的研究中发现:单个粒子通过某条特定路径的时间正比于该路径上所有节点度的连乘积.据此,文章提出基于随机行走机理的优化路由改进策略.该策略以节点度连乘积最小化为原则,通过调节可变参数,建立节点处理能力均匀分布的情况下最佳路由策略.通过分析比较不同路由策略条件下平均路由介数中心度,网络的临界负载量,平均路径长度以及平均搜索信息量等性能指标,研究结果表明,此改进路由策略在保证网络平均路径长度较少增加的前提下,使网络的传输能力获得最大幅度的提升. 关键词: 复杂网络 路由策略 负载传输  相似文献   

13.
This study proposes a probability routing strategy for improving traffic capability on scale-free networks. Compared with the shortest path routing strategy depending on central nodes largely and the efficient routing strategy avoiding hub routers as much as possible, the probability routing strategy makes use of hub routers more efficiently, transferring approximate average amount of packs of the whole network. Simulation results indicate that the probability routing strategy has the highest network capacity among the three routing strategies. This strategy provides network capacity that can be more than 30 times higher than that of the shortest path routing strategy and over 50% higher than that of the efficient routing strategy. In addition, the average routing path length of our proposed strategy is over 10% shorter than that of the efficient routing strategy and only about 10% longer than that of the shortest path routing strategy.  相似文献   

14.
In this paper, we propose an integrated routing strategy based on global static topologyinformation and local dynamic data packet queue lengths to improve the transmissionefficiency of scale-free networks. The proposed routing strategy is a combination of aglobal static routing strategy (based on the shortest path algorithm) and local dynamicqueue length management, in which, instead of using an infinite buffer, the queue lengthof each node i in the proposed routing strategy is limited by acritical queue length Qic. When the networktraffic is lower and the queue length of each node i is shorter than itscritical queue length Qic, it forwardspackets according to the global routing table. With increasing network traffic, when thebuffers of the nodes with higher degree are full, they do not receive packets due to theirlimited buffers and the packets have to be delivered to the nodes with lower degree. Theglobal static routing strategy can shorten the transmission time that it takes a packet toreach its destination, and the local limited queue length can balance the network traffic.The optimal critical queue lengths of nodes have been analysed. Simulation results showthat the proposed routing strategy can get better performance than that of the globalstatic strategy based on topology, and almost the same performance as that of the globaldynamic routing strategy with less complexity.  相似文献   

15.
一种有效提高无标度网络负载容量的管理策略   总被引:2,自引:0,他引:2       下载免费PDF全文
蔡君  余顺争 《物理学报》2013,62(5):58901-058901
现有研究表明明显的社团结构会显著降低网络的传输性能. 本文基于网络邻接矩阵的特征谱定义了链路对网络社团特性的贡献度, 提出一种通过逻辑关闭或删除对网络社团特性贡献度大的链路以提高网络传输性能的拓扑管理策略, 即社团弱化控制策略(CWCS 策略). 在具有社团结构的无标度网络上分别进行了基于全局最短路径路由和局部路由的仿真实验, 并与关闭连接度大的节点之间链路的HDF 策略进行了比较. 仿真实验结果显示, 在全局最短路径路由策略下, CWCS策略能更有效地提高网络负载容量, 并且网络的平均传输时间增加的幅度变小. 在局部路由策略下, 当调控参数0<α<2, 对网络负载容量的提升优于HDF策略. 关键词: 复杂网络 社团特性 负载容量 拓扑管理  相似文献   

16.
In this paper, an optimal routing strategy is proposed to enhance the traffic capacity of complex networks. In order to avoid nodes overloading, the new algorithm is derived on the basis of generalized betweenness centrality which gives an estimate of traffic handled by the node for a route set. Since the nodes with large betweenness centrality are more susceptible to traffic congestion, the traffic can be improved, as our strategy, by redistributing traffic load from nodes with large betweenness centrality to nodes with small betweenness centrality in the proceeding of computing collective routing table. Particularly, depending on a parameter that controls the optimization scale, the new routing can not only enlarge traffic capacity of networks more, but also enhance traffic efficiency with smaller average path length. Comparing results of previous routing strategies, it is shown that the present improved routing performs more effectively.  相似文献   

17.
Dan Wang  Yuanwei Jing  Siying Zhang 《Physica A》2008,387(12):3001-3007
By incorporating local traffic information into the shortest path routing strategy, we numerically investigate the effectiveness of the traffic awareness routing strategy for scale-free networks with different clustering. In order to characterize the efficiency of the packet-delivery process, we introduce an order parameter and an average transmission time that allow us to measure the network capacity by the critical value of phase transition from free flow to congestion. Compared with the shortest path routing protocol, the network capacity is greatly enhanced by the traffic awareness routing strategy. We also find that there exists an optimum value for the tunable parameter in the congestion awareness strategy. Moreover, simulation results show that the more clustered the network, the less efficient the packet-delivery process.  相似文献   

18.
In this paper, we propose a new routing strategy based on the minimum information path, named the optimal routing (OR) strategy, to improve the transportation capacity of scale-free networks. We define the average routing centrality degree of the node to analyze the traffic load on nodes of different degree. We analyze the transportation capacity by using the critical values of Rc, the average packet travel time, and the average path length. Both theoretical and experimental results show that the capacity of the network under our strategy will be maximized when the packet-delivery rate of the node is directly proportional to the degree.  相似文献   

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