随机流网络的d-下界点

本文主要对随机流网络的d-下界点进行了研究。首先,根据随机流网络的最大流,对容量向量进行了分类,并讨论了不同类之间的关系,给出了d-下界点与d-上界点的另一种定义方式。其次,改进了容量向量中寻找极小元（极大元）的算法,也是求d-下（上）界点的方法。     

通信网络的可靠性评估

通信网络的可靠性评估是一个难题。目前人们只对环型网和树型网进行可靠性分析。本文首先定义了通信网络的可靠性，依据图论提出了网络生成树的计算方法，以及网络可靠度的估算公式。最后给出了一个栅格型网的可靠度估算示例。     

工业以太网冗余技术分析

为了满足工业以太网对网络的可靠性要求，减少因网络故障造成的损失，网络冗余容错技术的提出增加了网络的可靠性和稳定性。文中介绍了网络冗余技术国内外研究的总体情况，讨论了多种网络冗余解决方案，包括生成树协议、快速生成树协议、环网冗余协议和分布式冗余网络协议，以及其他的网络冗余技术，着重讨论了分布式冗余网络协议，’最后对多种网络冗余解决方案进行了比较，特别指出了它们的局限性。     

舰载C3I系统通信网络可靠性效能分析

C^3I系统通信网络效能评估的影响因素复杂多变,一直是个棘手的问题．C^3I系统通信网络可靠性评估是C^3I系统效能评估的一个重要方面,从C^3I系统通信网络的最小连通子网一网络生成树入手,依据图论的方法,进行网络生成树数目的计算,并建立了C^3I系统通信网络的可靠度的数学模型。     

基于概念图的自然语言语义解释

语法分析器应用文法规则生成语法树来表示一名句子的语法结构。本文讨论用概念图表示自然语言的语义，描述一个从语法树开始生成概念图来解释句子语义的方法，生成过程是由语法树引导，把与每一个输入词相关的概念图连接成一个较大的概念图表示整修句子的语义。     

计算通信网络整体概率连通性的一种新算法

本文提出了一种计算网络整体概率连通性的新算法。该算法首先构造了一种多级状态空间分解法,对网络状态空间进行了分解,并对分解所得的生成事件提出了一种提出了一种特殊的生成子网构造法,从而有效减少了网络状态空间集。新算法通过迭代运算用上下界来逼近网络概率连通性的值,与传统算法相比,具有运算速度快、收敛性能好,很适合近似计算的特点。     

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     

通信网络扩展的一种优化方法

讨论了目前可靠性评估的常用方法和相应的测度指标,指出了当前可靠性评估技术的缺点和不足。针对以添加链路的形式扩展通信网络的过程,提出了一种基于生成树的通信网络扩展的优化方法,并且利用这种方法进行了某种网络拓扑结构扩展的仿真计算,与现存的其它方法的比较表明,这种基于生成树的优化方法设计合理、计算快速,可以有效地应用于实际的通信网络扩展的优化过程中。     

用户分配网络的设计与安装维修

有线电视用户分配网络由放大器、电缆、分支器和分配器等组成。分配网络的作用是给每个用户终端提供一个适当的信号电平。通常的设计是在放大器输出端设置一个或两个分配器，将放大器的输出分为若干路，每一路就是一条分支电缆，每条分支电缆上串接若干分支器或串接单元，将信号送到每一个用户终端。     

一种自适应的小波神经网络

本文受感知域划分思想的启发，将小波的多分辨分析与BP网结构相结合，构造了一种新的小波神经网络．该小波神经网络利用多分辨分析生成小波树，小波树的生长与网络的训练相结合，自适应地生成隐层结点，并且删除分类不佳的结点．以声纳信号进行了实验，结果表明：该网络充分发挥了小波的特点，将模式识别的特征抽取与分类器设计融为一体．     

求网络总可靠度的状态空间树法和精确分解算法

本文提出了求通信网络总可靠度的状态空间树法。它直接产生网络图的一个不交化树多层多项式,优点是计算量较小[计算时间复杂度为0(?),(?)为边数,n_1为叶数],所得表达式较短。在此基础上应用超图理论提出了求通信网络总可靠度的精确分解算法。用它进行网络图的m次分解,一台计算机所能计算的通信网络规模可以扩大m倍。     

Reliability of a stochastic-flow network with unreliable branches & nodes, under budget constraints

System reliability evaluation for flow networks is an important issue in quality management. This paper concentrates on a stochastic-flow network in which nodes as well as branches have several possible capacities, and can fail. The possibility is evaluated that a given amount of messages can be transmitted through the stochastic-flow network under the budget constraint. Such a possibility, system reliability, is a performance index for a stochastic-flow network. A minimal path, an order sequence of nodes & branches from the source to the sink without cycles, is used to assign the flow to each component (branch or node). A lower boundary point for (d, C) is a minimal capacity vector, which enables the system to transmit d messages under the budget C. Based on minimal paths, an efficient algorithm is proposed to generate all lower boundary points for (d, C). The system reliability can then be calculated in terms of all lower boundary points for (d, C) by applying the inclusion-exclusion rule. Simulation shows that the implicit enumeration (step 1) of the proposed algorithm can be executed efficiently.     

Optimal design improving a communication network reliability

Improvement of the reliability of a communication network is an optimal problem that finds some links to add to the network such that the reliability of the network reaches a given level and the total cost of these links is minimized. A decomposition method based on branch and bound is used for solving the problem. In order to speed up the solution procedure, an upper bound on system reliability in terms of node degrees is applied. Specially, when the threshold P_o is large enough, a new algorithm, the cut tree algorithm, can more effectively give the optimal solution.     

A New Algorithm for the Reliability Analysis of Multi-Terminal Networks

In a probabilistic network, source-to-multiple-terminal reliability (SMT reliability) is the probability that a specified vertex can reach every other vertex. This paper derives a new topological formula for the SMT reliability of probabilistic networks. The formula generates only non-cancelling terms. The non-cancelling terms in the reliability expression correspond one-to-one with the acyclic t-subgraphs of the network. An acyclic t-subgraph is an acyclic graph in which every link is in at least one spanning rooted tree of the graph. The sign to be associated with each term is easily computed by counting the vertices and links in the corresponding subgraph. Overall reliability is the probability that every vertex can reach every other vertex in the network. For an undirected network, it is shown the SMT reliability is equal to the overall reliability. The formula is general and applies to networks containing directed or undirected links. Furthermore link failures in the network can be s-dependent. An algorithm is presented for generating all acyclic t-subgraphs and computing the reliability of the network. The reliability expression is obtained in symbolic factored form.     

Optimization of connecting two communication networks subject to a reliability constraint

This paper considers optimization of two networks with a reliability constraint. The objective is to find some links to connect two networks, at a minimal cost, under the constraint that the system reliability of the resultant network is not less than a given level. A decomposition method based on branch and bound is used for solving the problem. In order to speed up the solution procedure, an upper bound on system reliability in terms of node degrees is applied. In particular, when the threshold P_o is large enough, a new algorithm, the cut tree algorithm, can more effectively give an optimal solution.     

A Simple Technique for Computing Network Reliability

A tree construction technique to compute a reliability expression of a network is derived. The technique is straight forward and good for both directed and undirected graphs. It gives mutually disjoint success branches. The reliability expression of each branch can be directly written by a set of rules. The reliability of the network can then be obtained by taking the direct sum of the reliabilities of the branches. It involves fewer multiplications than other known techniques. For a moderately complex network it is very easy to use this technique for evaluating reliability.     

Terminal-pair reliability of three-type computer communicationnetworks

The terminal-pair reliabilities, between the root and a leaf, of the two-center binary tree, the X-tree, and the ring-tree are computed; the beheaded binary tree is used as a benchmark. A building block is identified in the two-center binary tree from which a decomposition method is formulated. Another building block is identified for the X-tree and ring-tree from which a truss-transformation method is obtained. Computation has been carried out using algorithms based on the analysis. Although the ring-tree is the most reliable at all practical ranges of link and mode reliabilities, the X-tree and two-center binary tree are also good candidates because link reliability over 0.95 is quite common, and node reliability can be kept very high. The X-tree in particular is quite desirable due to its lower connectivity at each node and hence a lower implementation complexity. Three computational methods are presented. The simplicity of the two-center binary-tree algorithm blends with the hierarchical structure of the network itself because the states directly show that the level of computation can be summarized by some reliability subcomponents     

An algorithm for lower reliability bounds of multistate two-terminal networks

Network reliability is extensively used to measure the degree of stability of the quality of infrastructure services. The performance of an infrastructure network and its components degrades over time in real situations. Multi-state reliability modeling that allows a finite number of different states for the performance of the network and its components is more appropriate for the reliability assessment, and provides a more realistic view of the network performance than the traditional binary reliability modeling. Due to the computational complexity of the enumerative methods in evaluating the multi-state reliability, the problem can be reduced to searching lower boundary points, and using them to evaluate reliability. Lower boundary points can be used to compute the exact reliability value and reliability bounds. We present an algorithm to search for lower boundary points. The proposed algorithm has considerable improvement in terms of computational efficiency by significantly reducing the number of iterations to obtain lower reliability bounds.     

STATE SPACE TREE METHOD AND EXACT DECOMPOSITION ALGORITHM FOR FINDING NETWORK OVERALL RELIABILITY

First,the state space tree method for finding communication network overall re-liability is presented.It directly generates one disjoint tree multilevel polynomial of a networkgraph.Its advantages are smaller computational effort(its computing time complexity is O(en_l),where e is the number of edges and n_l is the number of leaves)and shorter resulting expression.Second,based on it an exact decomposition algorithm for finding communication network overallreliability is presented by applying the hypergraph theory.If we use it to carry out the m-timedecomposition of a network graph,the communication network scale which can be analyzed by acomputer can be extended to m-fold.     

树型电力网单故障分支识别的零泛器替代法

本文提出一种树型电力网单一故障分支的识别方法零泛器替代法。这种方法的特点是诊断所需要的端口变量易于测量,对于短路和断线故障都适用,测后计算量较少。适用于多分支的树型电力网单一故障分支的识别。经计算机模拟,证明了所提识别方法是有效的。