机会网络中基于有权社团结构图的路由协议研究

基于社团检测的机会网络路由算法大多采用无权重网络拓扑划分社团,仅将节点间的关系抽象为一条简单的无权重的边,忽略了节点关系的强弱程度。本文通过引入权重策略改进了QCA社团更新算法,提出了一种基于有权社团结构的路由算法,该算法解决了社团关系定量化单一的问题,更能真实反映出社团成员之间的关系。算法中,节点间的交互信息转化为权重,根据不同的网络环境选择不同的权重转化方案———归一化权重（normalized weight）和非归一化权重（non-normalized weight）。路由算法在检测到周围网络环境变化时自动切换权重计算方案以适应网络环境的变化。通过在仿真环境和真实数据集上测试和分析,该算法能够将网络中的节点划分出合理的社团结构,并在保证较高的传输成功率的情况下降低网络开销。     

基于模体结构和度信息的关键节点组识别

为了探究具有更小规模的高阶结构对关键节点组的影响,以优化网络传播为目标,提出了一种基于模体结构和度信息的关键节点组识别算法。基于模体结构对节点影响力进行评估,挖掘模体结构的核心节点,使用多准则妥协解排序（VIKOR）法将其与度信息进行融合,并利用种子排除算法对种子节点的邻居进行排除,有效减小影响力重叠问题。在SIR传播模型的基础上,选取6个不同的无向网络与4种基准算法进行比较,实验结果表明,所提算法在准确性和稳定性方面表现出更好的性能。     

ASON网络中的相对性保护策略

针对ASON网络业务量逐渐增大,而现有的保护机制使得有限的波长资源利用率不高的问题,基于ASON网络的小世界特征和无尺度特征,提出了一个新的保护策略-相对重要性节点(边)优先保护策略,该算法在利用PageRank算法挖掘出ASON网络上相对重要的节点以及边的情况下,对这些重要节点和边进行优先保护的方法,实现了在ASON网络上波长资源高效利用.通过实验仿真,验证了该保护策略可以极大地提高网络的性能,使得网络阻塞率减低,提高网络资源利用率.     

分级Ad Hoc网络簇形成算法的比较

Ad hoc网络是由若干移动节点组成的无中心网络，它在尚没有架设基础通信设施的地区及一些紧急情况下的通信将有广泛的用途。Ad Hoc网络一般有平面结构和分级结构两种结构，在网络中的节点数比较事的情况下需要使用分级结构．本文主要介绍四种簇形成算法及其优缺点和适用场合。     

基于节点异构度的覆盖网络副本一致性维护方法

分析比较了目前无结构覆盖网络中的副本一致性维护算法,引入了节点能力度量参数--节点异构度,提出了一种基于节点异构度的无结构覆盖网络副本一致性维护方法--NHDCOM.NHDCOM利用Chord组管理协议管理副本节点,采用基于指取表的分割方法动态获取副本节点的异构信息;为优化副本的更新时间,利用动态规划方法提出了一种基于时延的节点度约束生成树算法.给出了NHDCOM的维护策略.理论分析和模拟实验结果表明,NHDCOM能高效地维护副本的强一致性.     

有偏随机游走改进吸收中心性识别关键节点

针对无向网络吸收中心性算法中未考虑信息传递的有偏问题,提出一种基于节点的度信息有偏随机游走,改进吸收中心性识别关键节点的算法.首先在无向网络中利用节点的度信息,构建信息传递的转移概率矩阵并定义吸收节点,通过到达吸收节点的平均首次可达时间,衡量节点的重要性;将该算法向有向网络进行扩展研究,结合有向网络节点的出度、入度信息...     

基于电量均衡的无线传感器网络分簇算法

为了延长无线传感器网络的生命期,针对节点能耗分布不均匀的问题,提出一种电量均衡的分簇算法.该算法将节点剩余能量作为构建分簇结构的依据,对剩余能量较少的节点赋予一定的约束,使之成为普通节点,并使电量多的节点成为簇头节点,均衡网络电量负载,解决了网络中部分低电量节点担任骨干节点而导致能耗的问题,从而有效延长了网络的生命期.仿真实验证明了该算法的有效性.     

银行交易网络的链路预测

基于银行交易具有动态变化、时效性和重复性的特点,文中通过对银行网络进行清洗和压缩,研究银行网络的基本拓扑统计性质和聚类结构,并得到交易网络满足复杂网络的小世界和无标度特性。针对已有的链路预测算法在动态网络预测中的不足,提出一种自适应的动态链路算法对银行客户交易进行预测。该方法在预测网络的基础上添加了节点重要性与节点连接强弱性两个特性,并将3种预测算法结合随机算法进行了对比分析。随后将这3种算法运用到具有动态交易特性的3类真实数据集中进行实验验证。实验结果显示,新算法的预测精度约为75%。将该算法与经典的预测算法进行比较发现,提出的算法在预测方面的性能提升了5%~10%。     

基于排队论的数据通信网络性能优化

数据通信网络中的分组和交换节点可以用排队论的模型模拟分析。文章针对分组集散量和服务时间的最优解问题,对数据通信网络建立一个基于M/G/C/C状态独立排队网络模型,并运用RSM算法确定输入变量与因变量之间的关系,通过对响应的优先次序和期望值进行优化运算得到最大分组集散量和最短服务时间。     

基于结构相似度的大规模社交网络聚类算法

针对社交网络的有向交互性和大规模特性,该文提出一种基于结构相似度的有向网络聚类算法(DirSCAN),以及相应的分布式并行算法(PDirSCAN)。考虑社交网络中节点间的有向交互性,将行为结构相似的节点聚集起来,并进行节点功能分析。针对社交网络规模巨大的特点,提出MapReduce框架下的分布式并行聚类算法,在确保聚类结果一致的前提下,提高处理性能。大量真实数据集上的实验结果表明,DirSCAN比无向网络聚类算法(SCAN)在F1上可提高2.34%的性能,并行算法PDirSCAN比DirSCAN运行速度提升1.67倍,能够有效处理大规模的有向网络聚类问题。     

Pinning a complex dynamical network to its equilibrium

It is now known that the complexity of network topology has a great impact on the stabilization of complex dynamical networks. In this work, we study the control of random networks and scale-free networks. Conditions are investigated for globally or locally stabilizing such networks. Our strategy is to apply local feedback control to a small fraction of network nodes. We propose the concept of virtual control for microscopic dynamics throughout the process with different pinning schemes for both random networks and scale-free networks. We explain the main reason why significantly less local controllers are required by specifically pinning the most highly connected nodes in a scale-free network than those required by the randomly pinning scheme, and why there is no significant difference between specifically and randomly pinning schemes for controlling random dynamical networks. We also study the synchronization phenomenon of controlled dynamical networks in the stabilization process, both analytically and numerically.     

The rich-club phenomenon in the Internet topology

We show that the Internet topology at the autonomous system (AS) level has a rich-club phenomenon. The rich nodes, which are a small number of nodes with large numbers of links, are very well connected to each other. The rich-club is a core tier that we measured using the rich-club connectivity and the node-node link distribution. We obtained this core tier without any heuristic assumption between the ASs. The rich-club phenomenon is a simple qualitative way to differentiate between power law topologies and provides a criterion for new network models. To show this, we compared the measured rich-club of the AS graph with networks obtained using the Baraba/spl acute/si-Albert (BA) scale-free network model, the Fitness BA model and the Inet-3.0 model.     

基于局域世界的无线传感器网络分簇演化模型

当前无线传感器网络无标度演化模型研究往往将网络视为同质网络,且未充分考虑网络在真实情形下的演化特征,导致所获网络拓扑与实际网络差异明显。因此,基于局域世界理论,考虑无线传感器网络典型分簇结构、能耗敏感与真实网络中普遍存在的节点与链路退出的动态性行为等特征,提出无线传感器网络分簇演化模型。该模型与同类研究成果相比,更为接近真实网络情形。利用平均场理论推导出此模型具有无标度特征。通过研究拓扑生长对网络容错性能影响,发现扩大局域世界规模与提升饱和度约束上限可有效提升网络容错性能。与之相反,簇头比例与节点删除概率的上升将导致网络容错性能的下降。     

Epidemic spreading on scale-free networks with diversity of node anti-attack abilities

In this article,a modified susceptible-infected-removed(SIR) model is proposed to study the influence of diversity of node anti-attack abilities on the threshold of propagation in scale-free networks.In particular,a vulnerability function related to node degree is introduced into the model to describe the diversity of a node anti-attack ability.Analytical results are derived using the mean-field theory and it is observed that the diversity of anti-attack of nodes in scale-free networks can increase effectiv...     

量子无标度网络在随机攻击与蓄意故障下的纠缠渗流

通过在节点间建立成对纠缠态,构造了一个量子无标度网络.通过局域化纠缠交换的方式对网络中的节点进行随机攻击以及等概率地使网络中的节点发生蓄意故障,对比其纠缠渗流阈值变化.结果表明随机攻击下的阈值明显变小,蓄意故障下的阈值明显增大,体现了量子无标度网络的鲁棒性与脆弱性;纠缠浓缩下的量子无标度网络在随机攻击与蓄意故障下仍具有鲁棒性与脆弱性,但较纠缠浓缩前的鲁棒性变弱,说明真实网络具有较好的鲁棒性.     

有效提高Internet传输性能的社团结构改善策略

提出一种增添能最有效减弱网络社团特性的边以提高Internet网络传输性能的策略,即减弱社团结构策略（简称WCS策略）,并基于光逻辑链路可以提供与实际物理链路相当的高性能,以实现WCS策略的Internet网络的拓扑重构。在伪随机网络、具有社团结构的无标度人工网络和实际Internet网络上分别进行了基于全局最短路径路由和局部路由的实验。实验结果表明,利用WCS策略在社团之间少量边的添加,就能实现网络负载能力和平均最短路径的大幅改善。     

On the design of self-organized cellular wireless networks

It has been observed that complex networks such as the Internet, World Wide Web, social networks, and biological systems are self-organizing in nature and exhibit some common properties such as the power law degree distribution. Recently, two models (i.e., small world and scale-free network models) have been proposed and successfully used to describe the nature of such networks. In this article we investigate whether these concepts can also be applied to cellular wireless networks, which typically do not exhibit self-organizing or scalability properties due to the limited range of the wireless nodes. Our ultimate goal is to design robust, reliable, scalable, and efficiently utilized wireless networks via self-organizing mechanisms.     

Optimized priority based energy efficient routing algorithm for mobile ad hoc networks

Recently more and more research interest focuses on the energy efficient routing in mobile ad hoc networks and many related routing algorithms are reported. In this paper, a new optimized priority based energy efficient routing algorithm is presented and priority is added to the existing routing algorithm according to the residual energy proportion of the nodes. Lower residual energy means lower priority and the nodes with lower priority are less likely to forward packets to other nodes. The algorithm needs no global information of the networks and only a little modification is needed to the existing algorithm, so it is practical to be implemented. The algorithm can improve the performance of routing discovery, routing maintenance and cache management at the same time. Some optimization strategy is taken to reduce the network overhead and the lifetime of the network is much longer and the network with our algorithm can transfer much more effective data. Simulation with NS-2 is done and satisfying results are obtained with this algorithm. The results show that the algorithm is efficient.     

Heuristic algorithm for allocation of wavelength convertible nodesand routing coordination in all-optical networks

It is true that in all-optical networks, network performance can be improved by wavelength conversion. However, the switching node with wavelength conversion capability is still costly, and the number of such nodes should he limited in the network. In this paper, a performance optimization problem is treated in all-optical networks. We propose a heuristic algorithm to minimize an overall blocking probability by properly allocating a limited number of nodes with wavelength conversion capability. The routing strategy is also considered suitable to the case where the number of wavelength convertible nodes are limited. We validate the minimization level of our heuristic algorithm through numerical examples, and show that our algorithm can properly allocate nodes with conversion and decide routes for performance optimization