一般性问题

TN()61 01010001s一t路径确定方法的研究/姐云霄,吕航孙雨耕(天漱大学)11电路与系统学报.一2 00。到3).一87一9。确定网络、一t间的路径是利用路径枚举法计算网络可靠性及确定、一t路由所必须的.文中在对以往确定网络s一七间路径算法的研究基础上,提出了一种新的确定路径的算法一一邻接矩阵算法,该算法不仅节省计算机内存,减沙、了计算蚤,而且用节点序列表示的路径可方便地用于同时考虑节点和边失效情况下的网络苛刻性计算.图1参4(金)T例()6 1 01010()02复杂系统可靠性上下限预测的一种简化方法/董哲(哈尔滨理工大学)11电测与仪表·一2 00…     

计算无圈有向网络ST可靠性的一个新方法

本文考虑计算无圈有向网络的ＳＴ可靠性问题（至少存在一条从源点ｓ到汇点ｔ的正常运行道路的概率）。文章引进了深度优先搜索（Ｄｅｐｔｈ－ＦｉｒｓｔＳｅａｒｃｈ）有序根树的概念并提出一个新的计算无圈有向网络ＳＴ可靠性的拓扑公式。以该公式为基础,我们利用ＤＦＳ方法提出一个新的计算无圈有向网络ＳＴ可靠性算法,它能生成简洁的可靠性表达式,进而有效地计算无圈有向网络的ＳＴ可靠性。两个例子例证了我们的结论     

链路故障下终端间可靠性的新算法

设计了两个计算通信网中终端ｓ和ｔ间的所有最小割集的算法，利用它们链路故障下ｓ和ｔ间的可靠性，这两种算法都已用Ｃ语言编制了计算机程序，并通过机上调试，在运行速度，计算精度等方面两上算法各具特色。     

可靠性约束下的无线Mesh网络拓扑控制优化方法

为合理规划无线Mesh网络,确保在节约无线资源前提下网络长期可靠地运行,该文定义了无线Mesh网络不同节点之间的归一化相对可靠性约束条件计算公式,建立了网络拓扑控制优化的模型,并配套研究了可靠性约束下拓扑控制的计算方法。该方法把Prim最小生成树方法融入到最大流最小割算法过程中,计算节点间每跳链路距离最短的不相交路径,通过不相交路径数与网络拓扑可靠性的相关性,得到可靠性约束下的拓扑优化。阐述了计算方法的正确性,并给出时间及空间复杂度。通过仿真验证及对比分析,在指定2×sqrt(N)对节点间为4条不相交路径及其他节点间2条不相交路径的可靠性约束条件下,不同网络规模的吞吐量及时延平均性能分别提升15.3%及20.1%,表明了可靠性约束下的拓扑控制方法更加合理性与灵活性,更能满足实际无线网络拓扑控制的要求。     

电力计量主站通信网最大可靠性路径选择方法

为保证电力计量主站通信网平稳运行，提出基于蚁群算法的通信网最大可靠性路径选择方法。使用网络邻接矩阵算法推算全部节点间最短路径长度与数量，提取抽象化的通信网邻接矩阵，创建通信网可靠性评估模型；计算信息传输时延，将最大可靠性与最低传输时延当作路径选择的双重目标，初始化路径选择参数；凭借蚁群算法的自组织特征更新信息素，实现高精度、最大可靠性路径选择任务。实验结果表明，所提方法可有效优化电力计量主站通信网络带宽，提高网络吞吐率，为计量数据高效率传输提供借鉴与帮助。     

传感器网络中基于最短路径树的低延时节能路由算法

借助图论中最短路径和最小生成树的原理,在无线传感器网络中构建若干棵以Sink节点为根的最短路径源路由树。与最小生成树相比,最短路径树能保证路径上大部分节点找到节点间RSSI较强的通讯路径并以较少的跳数把数据传输给Sink节点,而最小生成树中的节点则需较多跳数。因此,提出的算法在一定程度上降低了延时。算法通过事先设定最低RSSI和节点最大剩余能量MRE来构建路由树,并修改已存在的路由算法,从而保证节点通讯的可靠性和网络的节能。     

Ad Hoc网络可靠性评估

针对一种特殊的通信网Ad Hoc网络,提出了一种可靠性评估算法,首先根据物理拓扑抽象出Ad Hoc网络模型,并充分分析Ad Hoc网络特点确定失效判据,依据失效判据进行可靠性建模,选择合适的可靠性模型。将Ad Hoc网络模型划分为逻辑上的一个个子区域,采用层次分析法确定各个子区域的权重系数,在各子区域内,利用最小定点割集确定Ad Hoc网络中的重要节点,同时根据生成树算法确定重要节点的权重系数,从而可以计算出Ad Hoc网络的可靠度。最后通过实例说明某Ad Hoc网络的可靠性评估。     

ZigBee路由协议算法的研究

通过对ZigBee中的Cluster-Tree算法以及对AODVjr中的路由发现进行研究,在Cluster-Tree邻居表的基础上提出捷径路由,从该节点周围的邻居节点中找出可以用少量跳数即可到达目的节点。此后通过路由代价函数,计算通过Cluster-Tree改进算法中找到节点路径的能量使用代价,选择可靠性较高的路径,从而可以延长网络生存周期和降低能耗。最后通过实例,验证了算法改进的可行性。     

基于网络编码的双路径组播树生成算法

 为了将网络编码技术引入到全光组播网络中,提出了能够在多项式时间完成的基于网络编码的双路径组播树生成算法.该算法主要包括两大步骤:首先,从给定的组播网络中根据节点间度平衡的原则为源节点和每个目的节点之间确定一条有向路径,从而建立一棵传统有向树并保证有向树中任意节点的出度尽可能小,减少节点之间的关联性;其次,在所建立的传统有向树的基础上,从每一个目的节点到源节点根据冲突回溯原则建立源节点和每个目的节点之间的第二条路径,并保证源节点到任意目的节点间的两条路径为分离路径.算法中包含的约束原则能够保证所建立的双路径组播树包含最少的编码节点,从而使得所建立的组播树支持光域网络编码高效率实现,实现基于网络编码的全光组播并提升全光组播的性能.     

基于最短路径的网络可靠性评估算法

介绍了通信网络可靠性算法的研究现状,分析了各种可靠性算法的优点和不足.从网络拓扑结构和可靠性定义出发,研究了网络可靠性影响因素,建立了可靠性评估模型,对算法思想进行了描述.在网络最短路径和次短路径的基础上,提出了端到端的网络可靠性评估算法,根据网络中的薄弱节点,求得了整个网络可靠性值的近似值.以实例模拟计算,说明其算法...     

Reliability Evaluation in Computer-Communication Networks

The network reliability for a computer-communication network is defined and a method based on spanning trees is proposed for its evaluation. The network reliability expression and s-t terminal reliability expression are compared assuming an equal probability of survival for each communication link. Examples illustrate the method.     

Reliability of systems with two failure modes by using structure functions

This paper deals a three-state (normal, short-mode and open-mode failures) device network that is required to control the quantity of s-t flow. If the control policy is to pass the flow or to shut off the flow, i.e. the amount of s-t flow equals one, this network system is a conventional three-state system. In order to obtain the reliability of the network system, we propose a new structure function. Some examples are presented to show that using the structure function simplifies the reliability calculation.     

一个计算无圈有向网络可靠度的新算法

本文对无圈有向网络的可靠度计算进行了研究。提出了加权有序根树的概念，给出了路径集合的一种特殊排序方法，导出一个计算无圈有向网络可靠度的拓扑公式。在该公式的基础上提出了一个新的计算无圈有向网络可靠度的不交积和算法，算法可以生成简洁的可靠度表达式，从而可以有效地计算无圈有向网络的可靠度。同时验证了算法的有效性。     

Network s-t reliability bounds using a 2-dimensional reliabilitypolynomial

Computing the reliability of a generic network is computationally difficult, and an exact solution is unattainable for many problems. Faced with this computational difficulty, two compromises are usually made: (1) be content with reliability bounds instead of exact reliability; and (2) simplify analysis by assuming that all but 1 component-type are perfectly reliable. This paper relaxes the assumption of perfect components and computes the s-t reliability of a network whose operation is a function of the reliability of 2 component types (nodes and links.) The extension of the reliability polynomial to 2 dimensions removes the need to assume that links or nodes are perfectly reliable     

Topological layout of links for optimizing the s-t reliability in a computer communication system

Large-scale Computer Communication Networks (CCN) are coming into use primarily because of the economy achieved through resource sharing. A fundamental consideration in the design of a CCN is the reliability between any pair of nodes and the maximum permissible cost, these characteristics being largely dependent upon the topological layout of the links, their costs and reliabilities. In this paper, having the knowledge of the locations of the various computer centres (nodes), maximum permissible cost of installing the links and the possible position of links, an heuristic algorithm for obtaining an optimal network topology which gives the maximum s-t reliability is presented. The method is general and is easily computerizable.     

电信网络运维分析与故障预测算法研究

文中旨在研究电信网络运维分析与故障预测算法,以提高电信网络的稳定性和可靠性。首先,通过收集大量的网络性能数据和故障记录,建立一个综合性的数据集。然后,提出了一种基于机器学习的故障预测模型,该模型利用了时间序列分析、特征工程和监督学习算法。实验结果表明,该模型在故障预测方面具有显著的优势,能提前识别潜在故障并采取相应的维护措施,从而降低网络故障的影响。最后,强调了故障预测算法在电信网络运维中的重要性,并为网络运维提供了有力的工具和方法。     

Bounding algorithms for two-terminal network reliability

Determining the exact reliability of a complex network involves extremely large amount of computation. Consequently, it is appropriate to discuss method for approximating network reliability. This paper develops methods for obtaining upper and lower bounds for two-terminal network reliability. Construction of different layers for a network is used to develop an algorithm to compute an upper bound for the reliability of a network. The nodes of this network are completely reliable and arcs fail statistically independently with known probabilities. A simple approach, to obtain a lower bound for the reliability of the network is also presented. Examples illustrate the use of the algorithms and show that the proposed bounds fare better than the well-known Esary and Proschan bounds.     

Efficient and Exact Reliability Evaluation for Networks With Imperfect Vertices

The factoring theorem, and BDD-based algorithms have been shown to be efficient reliability evaluation methods for networks with perfectly reliable vertices. However, the vertices, and the links of a network may fail in the real world. Imperfect vertices can be factored like links, but the complexity increases exponentially with their number. Exact algorithms based on the factoring theorem can therefore induce great overhead if vertex failures are taken into account. To solve the problem, a set of exact algorithms is presented to deal with vertex failures with little additional overhead. The algorithms can be used to solve terminal-pair, k-terminal, and all-terminal reliability problems in directed, and undirected networks. The essential variable is defined to be a vertex or a link of a network whose failure has the dominating effect on network reliability. The algorithms are so efficient that it takes less than 1.2 seconds on a 1.67 GHz personal computer to identify the essential variable of a network having 2⁹⁹ paths. When vertex failures in a 3 times 10 mesh network are taken into account, the proposed algorithms can induce as little as about 0.3% of runtime overhead, while the best result from factoring algorithms incurs about 300% overhead     

Consideration of node failures in network-reliability calculation

Terminal-pair reliability is a common measure of telecommunication network reliability, and many algorithms for calculating it have been published. Most such algorithms presume perfect nodes; although some have presumed imperfect nodes. This paper presents a very simple, uncomplicated way to account for imperfect nodes