多信道无线网状网自适应路由算法

针对无线网状网的网络容量优化问题,通过建立无线网状网容量优化的数学模型,利用线性规划公式对无线网状网的路由问题进行描述,在此基础上提出了一个自适应路由算法。根据网络的拓扑结构和业务请求特点,自适应地改变路由扩张因子和负载均衡率进行优化路由,达到提高无线网状网的网络容量的目的。仿真结果表明,该算法能明显提高网络容量。     

基于WDM传输网的动态路由算法

波分复用技术(WDM)作为一种公认的最佳光纤扩容技术已被广泛应用在国际和国内长途骨干网上。路由算法与波长分配(RWA)是WDM网中的重要技术之一,评价RWA算法的一个重要标准是网络阻塞率。采用合适的路由算法可以大大降低网络的阻塞率。该文采用一种结合了再生节点选择的动态RWA算法来解决WDM网中的波长路由问题,并通过光纤通道拓扑的优化算法来进一步优化。通过建模仿真,研究了NSFNET网络优化前后阻塞率的变化,仿真的结果证明采用该优化算法可以降低网络的阻塞率。     

移动自组网中的最长生命期路径

动态拓扑是移动自组网区别于其他形式网络的本质特征,对其进行研究具有很大的理论价值和工业应用背景.提出一种方法,利用网络的最长生命期路径来研究其拓扑的动态性.在已有研究的基础上,改进了网络的数学模型,弥补了以往模型无法很好地描述移动自组网动态拓扑的缺陷,并在此基础上提出了最长生命期路贩径算法.利用该算法计算网络中的最长生命期路径,深入研究了其持续时间的分布规律.同时证明了使用最长生命期路径作为路由,可以使网络的重路由次数最少.模拟实验表明,利用对数正态分布可以很好地描述移动自组网的最长生命期路径持续时间.实验结果表明,与以往利用最短路径作为研究对象相比,最长生命期路径和最小重路由更适合用来衡量网络的动态性.     

无线网状网跨层路由的研究

目前,无线网状网跨层路由设计方兴未艾,以往无线路由设计是基于最小跳数的,缺少对无线网状网特性的综合考虑,并不能充分发挥出无线网状网的优势。该文提出了基于"队列负载率"和"链路传输效率"的跨层路由协议算法,通过将MAC层的网络状态信息传递给网络层的路由代理,以便选择负载较小的最佳路由。通过仿真可以发现,改文提出的路由不仅显著提高了吞吐量,而且使包的投递更加可靠,提高了QoS。     

基于Q Learning算法的区域配网业务路由分配方法研究

传统的配网业务路由分配方法的链条占用率过高,导致丢包率较大。为此,设计了基于Q Learning算法的区域配网业务路由分配方法。按照传统分类方式划分业务路由中的性能指标,根据路由约束条件计算指标的约束值,从而确定业务路由的最优传输路径。结合Bellman Equation方法不断计算并更新配网中的Q值,再综合节点和网络业务指标,利用Q Learning算法计算得到区域配网中的风险均衡度。不断变换VNFs的路由顺序将其转换为TSP路由问题,最终得到路由分配矩阵,实现区域配网业务路由的分配。实验结果表明:与传统分配方法相比,基于Q Learning算法的分配方法的链条占用率低,有效减小了业务数据转发过程的丢包率。     

一种多速率移动自组网中的拓扑控制算法

提出了一种移动自组网中的拓扑控制算法MATC(multi-rate aware topology control),该算法充分考虑了无线环境中固有的多速率特性,在保证原有网络连接性的前提下删除部分低速链路,为上层的路由协议构造一个良好的拓扑,确保按需路由协议能够在一跳范围内发现最优路由.大量仿真结果表明,MATC对网络性能有较大的提高.     

Petri网与蚁群算法在CDN网络路由中的应用

CDN让用户以最快的速度从最近的地方获得所需的信息,它对QoS路由提出了更高的要求,单纯的采用蚁群算法或是依靠Petri网模型中变迁发生寻径的方法都不能较好的解决CDN路由问题。基于稳定的CDN网络构建图状拓扑结构,提出了一种将Petri网与蚁群算法相结合,考虑多个路由限制的优化QoS路由算法。实验仿真表明,该算法能有效地求解CDN网络中的路由问题。     

煤矿井下ZigBee无线传感器网络路由协议的研究

文章介绍了无线传感器网络的发展及其特点,在分析比较了目前流行的几种无线传感器网络路由协议的基础上,结合煤矿井下掘进工作面的特点和需求,提出了一种适用于掘进工作面的网状拓扑结构的ZigBee无线传感器网络的路由算法,并从路由建立、路由维护、路由恢复等方面进行了详细描述。该路由算法对其它具有ZigBee网状拓扑结构的系统具有一定的参考价值。     

自组网中基于熵的定向洪泛QoS路由算法研究

为了减少移动自组网中路由频繁失效和重构,提高网络性能和资源利用率,提出了基于熵的定向洪泛QoS路由算法。该算法利用定向洪泛的机制控制路由请求转发范围,降低网络的控制开销;并采用一种度量方法——熵来选择稳定的路由,减少重路由,提高数据成功传输率。利用OPNET对算法进行仿真,结果表明该算法能以较小控制开销获得较好的数据传输,降低了路由重构的概率,适合移动自组网的高度动态的特点。     

基于小世界的无线传感器网络的路由算法

针对小世界的拓扑特性,提出一种基于小世界的无线传感器网络(WSN)的路由算法。该路由算法引入超级节点环概念,将超级节点环视为无向图,利用改进的Floyd算法计算出最短传输路径,缩短路由建立时间,进而提高网络的传输效率,降低无线传感器网络的能耗。仿真结果表明,该算法与针对小世界提出的路由算法PSCF、SWRP和MH相比,在路由建立时间、能量消耗和网络吞吐量方面效果显著。     

Parallel transient dynamic non-linear analysis of reinforced concrete plates

This article describes how parallel processing may improve the computational efficiency of the transient dynamic non-linear analysis of reinforced concrete plates subjected to blast or seismic loading. A parallel scheme for the time marching procedure is presented using the explicit Newmark’s algorithm. The finite element formulation with the material modelling (of a strain-rate sensitive hardening–softening, elasto–viscoplastic model accounting for cracking and crushing) is described. The complexity of the material laws and their modelling, induced by the extreme loading conditions, requires vast computational effort per time step. It will be shown that very high computational efficiency may be obtained by decomposing the finite element mesh into a number of sub-domains for distributed analysis on multiple processors. This high efficiency is achieved using distributed memory MIMD architectures (including transputer networks), where the routing of the messages represents significant overhead in terms of inter-processor communication because of limitations resulting from the processor network topology. Through examples it will be demonstrated how this efficiency depends on the problem size (i.e. the level of refinement of the problem idealisation), the number of sub-domains and the status of the analysis with regards to the states of the material.     

Reliability optimization of topology communication network design using an improved ant colony optimization

Network design problem is a well-known NP-hard problem which involves the selection of a subset of possible links or a network topology in order to minimize the network cost subjected to the reliability constraint. To overcome the problem, this paper proposes a new efficiency algorithm based on the conventional ant colony optimization (ACO) to solve the communication network design when considering both economics and reliability. The proposed method is called improved ant colony optimizations (IACO) which introduces two addition techniques in order to improve the search process, i.e. neighborhood search and re-initialization process. To show its efficiency, IACO is applied to test with three different topology network systems and its results are compared with those obtained results from the conventional approaches, i.e. genetic algorithm (GA), tabu search algorithm (TSA) and ACO. Simulation results, obtained these test problems with various constraints, shown that the proposed approach is superior to the conventional algorithms both solution quality and computational time.     

蒙太奇网格融合

三维物体融合是一种新的几何造型方法,它利用三维模型之间的剪贴操作从两个或多个现有的几何模型中光滑融合出新的几何模型.提出了一种基于局部调和映射的三维网格蒙太奇融合新方法.首先利用网格上的近似等距线算法来抽取出待融合区域,然后对两个待融合区域进行带内孔的调和映射参数化,最后通过拓扑合并和融合控制来实现网格的光滑融合.与原有的基于全局调和映射的融合方法相比,新方法的算法效率大幅度提升,求解时间不再随融合模型顶点数的增加而呈指数增长;减少了二维网格拓扑合并中奇异情况出现的概率,提高了算法的稳定性;被剪切网格的细节得到完整保留;消除了原算法对融合区域拓扑的限制.实验结果表明,此方法可以用来生成许多三维动画中的特殊夸张造型效果,在影视动画中具有应用价值.     

无线多接口多信道Mesh网络下多径路由协议分析

针对无线多接口多信道Mesh网络环境,对两种多径路由模型进行比较分析。根据支持多接口多信道的无线设备的特点,提出了一套较为高效的路由方式。该方案从源节点到目的节点利用提出的接口分配策略,从不同的接口和信道建立多条可同时工作的路由和多条不重叠的备份路由以大幅提升网络性能。它充分利用了多接口多信道移动设备的性能优势,更适合Mesh网络的拓扑特点。仿真测试表明,使用该方案,在端到端时延,网络吞吐量等方面提供了更佳的性能。     

直线引导的Torus结构路由算法

为了提高片上网络在Torus拓扑结构下的路由通信效率,提出了一种基于直线引导思想的路由算法Tline。该路由算法将Torus拓扑结构的片上网络拓展为类似Mesh结构的坐标平面,以数据包的源节点和目的节点构成的直线为路由转发方向,并根据周围邻近节点的拥塞状况选择传输路径方向实现部分自适应路由。实验结果表明,与XY、OE路由算法相比,在热点流量模式下Tline路由算法具有较好的路由性能,且平均能耗降低约8%。     

基于逆 Loop 细分的半正则网格简化算法

摘 要：三维网格简化是在保留目标物体几何形状信息的前提下尽量减小精细化三维模型 中的点数和面数的一种操作,对提高三维网格数据的存取和网络传输速度、编辑和渲染效率具 有十分重要的作用。针对大多网格简化算法在简化过程中未考虑网格拓扑结构与视觉质量的问 题,提出了一种基于逆 Loop 细分的半正则网格简化算法。首先根据邻域质心偏移量进行特征 点检测,随后随机选取种子三角形,以边扩展方式获取正则区域并执行逆 Loop 细分进行简化。 最后,以向内分割方式进行边缘拼接,获取最终的简化模型。与经典算法在公开数据集上进行 实验对比,结果表明,该算法能够在简化的同时有效地保持网格特征,尽可能保留与原始网格 一致的规则的拓扑结构,并且在视觉质量上优于边折叠以及聚类简化算法。     

Minimizing Communication Penalty of Triangular Solvers by Runtime Mesh Configuration and Workload Redistribution

In this article, we study the effects of network topology and load balancing on the performance of a new parallel algorithm for solving triangular systems of linear equations on distributed-memory message-passing multiprocessors. The proposed algorithm employs novel runtime data mapping and workload redistribution methods on a communication network which is configured as a toroidal mesh. A fully parameterized theoretical model is used to predict communication behaviors of the proposed algorithm relevant to load balancing, and the analytical performance results correctly determine the optimal dimensions of the toroidal mesh, which vary with the problem size, the number of available processors, and the hardware parameters of the machine. Further enhancement to the proposed algorithm is then achieved through redistributing the arithmetic workload at runtime. Our FORTRAN implementation of the proposed algorithm as well as its enhanced version has been tested on an Intel iPSC/2 hypercube, and the same code is also suitable for executing the algorithm on the iPSC/860 hypercube and the Intel Paragon mesh multiprocessor. The actual timing results support our theoretical findings, and they both confirm the very significant impact a network topology chosen at runtime can have on the computational load distribution, the communication behaviors and the overall performance of parallel algorithms.     

对角网格中的无死锁自适应路由算法

网格是多计算机中应用广泛的互连结构,提出了一种新的互连结构－对角网格。并在这种结构上提出了一类自适应无死锁的路由算法－负优先算法,证明了此算法的无死锁性。对角网格是可平面图,其结构简单,可扩充性非常好。负优先自适应路由算法的突出优点是对硬件逻辑要求简单,无须增加虚拟通道即可达 死锁和自适应。     

Deadlock free routing algorithms for irregular mesh topology NoC systems with rectangular regions

The simplicity of regular mesh topology Network on Chip (NoC) architecture leads to reductions in design time and manufacturing cost. A weakness of the regular shaped architecture is its inability to efficiently support cores of different sizes. A proposed way in literature to deal with this is to utilize the region concept, which helps to accommodate cores larger than the tile size in mesh topology NoC architectures. Region concept offers many new opportunities for NoC design, as well as provides new design issues and challenges. One of the most important among these is the design of an efficient deadlock free routing algorithm. Available adaptive routing algorithms developed for regular mesh topology cannot ensure freedom from deadlocks. In this paper, we list and discuss many new design issues which need to be handled for designing NoC systems incorporating cores larger than the tile size. We also present and compare two deadlock free routing algorithms for mesh topology NoC with regions. The idea of the first algorithm is borrowed from the area of fault tolerant networks, where a network topology is rendered irregular due to faults in routers or links, and is adapted for the new context. We compare this with an algorithm designed using a methodology for design of application specific routing algorithms for communication networks. The application specific routing algorithm tries to maximize adaptivity by using static and dynamic communication requirements of the application. Our study shows that the application specific routing algorithm not only provides much higher adaptivity, but also superior performance as compared to the other algorithm in all traffic cases. But this higher performance for the second algorithm comes at a higher area cost for implementing network routers.     

MRABM:一种新的基于mesh结构的多径路由算法

针对移动AdHoc网络提出了一种新的基于mesh结构的多径路由算法MRABM(MultipathRoutingAlgorithmBasedonMeshStructure),该算法采用目的节点建立和更新mesh结构的机制。该算法不仅为每个源节点、中间节点提供了到目的节点最优路径,而且为每个节点建立了到目的节点的多条路径。当节点移动造成链路断开时,该算法能避开断开的链路,迅速沿其它路径转发数据,不需要路由修复和路由重建过程,从而降低了丢包率和端到端的延时。对大流量数据的传输,该算法能有效利用网络资源,减少网络拥塞。因此该算法能很好地适应网络拓扑结构的动态变化。