一种评价通信网节点重要性的新方法——节点孤立法

提出了一种评价通信网节点重要性的新方法--节点孤立法,并提出了节点核度积的概念,认为通信网中最重要的节点是孤立后所对应的节点核度积最大的节点.该方法考虑了网络的连接状况,并且动态地考虑了网络中所有节点相互通信的最短路径总长度的增加值.该方法是基于全网性能对节点重要性进行评价,通过比较节点的核度积,判断通信网中任意两个节点的相对重要性,而且使用了一种模2的矩阵运算方法,可以快速得到节点通信的最短路径.理论分析和仿真实验结果表明,该方法的计算复杂度和对节点重要性评价的准确性优于其它算法.     

铁路通信网可靠性探讨

随着通信技术迅速发展,铁路通信网正在迅速发展成为一个高度数字化的大型通信网络。由于铁路运输指挥系统、调度管理信息系统、客票预售系统、客货运管理、车辆追踪等大量铁路运输生产工作对通信网络具有高度的依赖性。因此通信网络的可靠性、有效性和运行效率至关重要。     

浅谈计算机通信网可靠性设计要求

随着计算机技术和通信技术的飞速发展．计算机通信网已经涉及到了我们工作和生活中的很多方面,几乎社会的每一个领域都在运用计算机通信网。由此可见,如何保证通信网的可靠性设计已经成为了不可回避的现实问题,本文通过浅谈计算机通信网络可靠性设计要求,希望能在论述中为通信网可靠性设计提供可行性方案。     

电力数据通信网的规划与设计

当前信息技术和网络技术的发展使得我们在很多行业中都能够发现它们的身影,并且信息技术和网络技术的运用确实给我们的生活和工作带来了极大地便利,在电力系统中信息技术和网络技术的运用也起到了极为突出的作用,其中电力数据通信网的建立就是一个突出的代表,本文就重点针对电力数据通信网首先介绍了智能光网络在电力数据通信网中的应用,然后重点介绍了任何提高电力数据通信网的可靠性。     

基于PTN配电通信网的实时性和可靠性研究

随着我国电网智能化发展进程的加快,一体化信息平台的建立是配网通信系统发展的必然趋势,是配网业务中通信质量的保障。PTN技术在配电通信网建设中具有重要的作用,能够提高通信网的实时性与可靠性,本文首先对PTN配网综合通信系统设计原则进行分析,然后对PTN配电通信网可靠性进行研究。     

基于模糊灰关联分析的通信网运行可靠性评估

基于模糊灰关联度理论，提出了通信网运行可靠性评估的方法，通过实例验证，该方法有效。     

电力调度通信网设计技术的探讨

简要介绍了电力调度通信网建设的现状及存在的问题,对电力调度通信网的可靠性、稳定性、录音系统及调度监控设计等方面存在的问题进行分析,并对几个存在问题的解决方案或措施进行探讨。     

电力通信网中通信监测技术应用

随着以计算机技术为核心的网络的兴起和快速发展,计算机网络技术在电力通信监测系统中得到广泛的使用,在很大程度上提高了电力通信网的管理水平。本文对通信监测技术在电力通信网中的应用进行了相关的探讨。     

论电力通信网建设存在问题及方法

通过对通信专业在电力系统中的定位和电力通信的现状分析．从员工意识、完善机制、技术体系、服务体系等方面阐明了电力企业通信建设和运营管理中存在的问题以及面临的机遇。对人员建设、机制建设、服务体系建设等方面提出见解。     

直接差分外节点法中复合节点领域的凝固计算方法

直接差分法是铸件凝固模拟的一种重要方法,外节点法是其网格剖分方法之一.其节点位置与剖分网格的顶点位置一致,因而使得系统的网格剖分和节点数据处理都比较方便.铸件-铸型体系往往是由多种材料构成.对于异类材料分界面上的节点,外节点法的计算领域内一般包括两种以上具有不同热物性值(包括潜热作用)的材料区域,这里称之为\"复合节点领域\".本文提出\"复合节点领域综合比热容\"的概念,用其推出复合节点领域的通用差分计算格式,以便于编制通用计算程序,应用于复杂的铸件-铸型体系.本文包括:①综合比热容的通用计算式;②复合节点领域中四种常见边界条件的传热计算方法,即:理想接触导热界面、有热阻接触导热或对流界面、辐射换热界面、已知法向热流率的换热界面;③复合节点领域的通用差分格式;④该通用差分格式的稳定条件.此计算方法应用于被覆铸造(铸渗技术)的数值模拟程序之中,取得理想结果.     

Exploring Collective Dynamics in Communication Networks

A communication network, such as the Internet, comprises a complex system where cooperative phenomena may emerge from interactions among various traffic flows generated and forwarded by individual nodes. To identify and understand such phenomena, we model a network as a two-dimensional cellular automaton. We suspect such models can promote better understanding of the spatial-temporal evolution of network congestion, and other emergent phenomena in communication networks. To search the behavior space of the model, we study dynamic patterns arising from interactions among traffic flows routed across shared network nodes, as we employ various configurations of parameters and two different congestion-control algorithms. In this paper, we characterize correlation in congestion behavior within the model at different system sizes and time granularities. As expected, we find that long-range dependence (LRD) appears at some time granularities, and that for a given network size LRD decays as time granularity increases. As network size increases, we find that long-range dependence exists at larger time scales. To distinguish effects due to network size from effects due to collective phenomena, we compare congestion behavior within networks of selected sizes to congestion behavior within comparably sized sub-areas in a larger network. We find stronger long-range dependence for sub-areas within the larger network. This suggests the importance of modeling networks of sufficiently large size when studying the effects of collective dynamics.     

基于BP神经网络的非平稳激励机械系统响应预估

利用ＢＰ人工神经网络进行非平稳激励条件下机械系统动态响应评判指标值与系统设计参数之间函数的逼近，采用收敛效率较高的学习率自适应调整算法，利用少数几次的方程求解结果进行网络训练，便可得到高效的响应评估映射，较多地减少了动态优化中评判值的计算规模。     

A new approach to the d-MC problem

Many real-world systems (such as cellular telephones, transportation, etc.) are multistate-node acyclic network (MNAN) composed of multistate-nodes. Such network has a source node (position) where the signal source is located, a number of sink nodes that only receive the signal, and a number of intermediate nodes that retransmit the received signal to some other nodes. The non-sink node has different states determined by a set of nodes receiving the signal directly from it. The reliability of MNAN can be computed in terms of minimal trees (MTs). Based on the Branch-and-Bound algorithm, we developed an intuitive algorithm that is simpler than the best-known existing method. The computational complexity of the proposed algorithm is also analyzed. One example is illustrated to show how all MTs are generated by the proposed algorithm. The reliability of this example is then computed.     

A multi-objective discrete reliability optimization problem for dissimilar-unit standby systems

A new methodology for the reliability optimization of a k dissimilar-unit nonrepairable cold-standby redundant system is introduced in this paper. Each unit is composed of a number of independent components with generalized Erlang distributions of lifetimes arranged in a series–parallel configuration. We also propose an approximate technique to extend the model to the general types of nonconstant hazard functions. To evaluate the system reliability, we apply the shortest path technique in stochastic networks. The purchase cost of each component is assumed to be an increasing function of its expected lifetime. There are multiple component choices with different distribution parameters available for replacement with each component of the system. The objective of the reliability optimization problem is to select the best components, from the set of available components, to be placed in the standby system to minimize the initial purchase cost of the system, maximize the system mean time to failure, minimize the system variance of time to failure, and also maximize the system reliability at the mission time. The goal attainment method is used to solve a discrete time approximation of the original problem.      

ATM网络中VCC的实时动态路由调度的神经网络新方法

针对神经网络因其强并行处理能力极适用于ＡＴＭ网络实时动态路由调度,提出了一种基于Ｈｏｐｆｉｅｌｄ神经网络的新路由算法,该算法网络拓扑及链路长度参数仅仅与神经元偏置电流有关,使得其硬件实现及逻辑控制非常简单。仿真结果证明了这种新路由算法的自适应性和鲁棒性。     

一种ATM网络中的动态路由算法

针对前期工作中讨论的多阶段虚通道（ＶＰ）控制和ＶＰ拓扑优化问题，以及基于在每一个源目（ＳＤ）节点对之间存在一组备选路由集这一假设的相应的优化算法，提出了一个补充算法，它能够求出任意两节点间的所有可能路径。在此基础上，进一步研究了一种动态虚通路（ＶＣ）路由策略。与其它路由策略不同，它是在更一般的网络环境中加以考虑的。最后，给出了一个动态ＶＰ路由算法，这是动态ＶＣ路由策略中的一个重要组成部分。理论分析和试验结果表明，这些算法是正确的，且有极高的实用价值。     

Application of the fault tree analysis for assessment of power system reliability

A new method for power system reliability analysis using the fault tree analysis approach is developed. The method is based on fault trees generated for each load point of the power system. The fault trees are related to disruption of energy delivery from generators to the specific load points. Quantitative evaluation of the fault trees, which represents a standpoint for assessment of reliability of power delivery, enables identification of the most important elements in the power system. The algorithm of the computer code, which facilitates the application of the method, has been applied to the IEEE test system. The power system reliability was assessed and the main contributors to power system reliability have been identified, both qualitatively and quantitatively.     

模糊神经网络的快速学习算法研究

对模糊神经网络的快速学习算法进行了研究,提出ＦＮＮ的最小二乘－单纯形产算法。解决了ＦＮＮ采用梯度型算法学习时所固有的局部收敛问题及跗算法在线应用的问题。与梯度型算法以及ＧＡ相比,ＬＳ－Ｓｉｍｐｌｅｘ算法具有更高的学习精度和更快的收敛速度,所得的ＦＮＮ具有良好的泛化性能。     

政府网资源的开发策略

本文分析了“政府上网工程”现状,认为充分开发政府网资源,实施“区内企业上网工程”是政府网进一步发展的关键,并提出了开发政府网资源的三个策略：提供政务网上处理、信息资源服务和建立政府信息门户等增值服务。这样,不仅提高了政府网的经济和社会效益,促进政府网的进一步发展完善,也将带动区内企业的信息化。     

求矩阵符号函数的割线法及其收敛性

符号函数是求解来自控制论中相关的Lyapunov方程和Riccati方程的有力工具,它也用来解某些特征值问题和计算不变子空间.本文给出了求矩阵符号函数的割线法,证明了该方法对于特殊的初始矩阵是全局超线性收敛的,并给出了数值试验,并将割线法与Newton法进行了比较,理论上和数值上均验证了割线法是求矩阵符号函数的有效数值方法.