A strictly nonblocking network based on nonblocking 4×4 optical switches

Recently, the demand for communication has been growing rapidly. Hence, optical multistage network technologies are more appreciated nowadays. A double-layer network is a strictly nonblocking network, and it has the lowest system insertion loss of non-dilated networks. A Beneš network is a rearrangeably nonblocking network, and it has the same system insertion loss as a double-layer network. We have proposed the use of modified polarization selection elements (PSEs). The system insertion loss, number of drivers, and number of required components of a double-layer network could be reduced if it is constructed with modified PSEs. A nonblocking 4×4 optical switch with two stages of polarization selective elements has been presented in our previous study. Based on this nonblocking 4×4 optical switch, we propose a strictly nonblocking network structure which features even lower system insertion loss than those of a double-layer network and a Beneš network. The signal-to-noise ratio of the proposed network structure is a constant, and is higher than the constraint, although it is lower than that of the double-layer network. The number of major components of the proposed network is less than that of a double-layer network and larger than that of a Beneš network, since a Beneš network is rearrangeably nonblocking. We also offer a routing algorithm for the new proposed network; the time complexity of the routing algorithm is O(1).     

无线传感器网络规模可扩展性的实现算法

无线传感器网络是由许多分布的智能传感器节点组成的多跳无线网络.针对无线传感器网络的特点,在能量有效的传感器网络MAC协议下,提出并实现了网络自适应规模扩展的算法.并利用网络仿真工具NS-2(network simulator 2.27版)实现仿真.该算法在无线传感器网络MAC层实现了网络规模的可扩展性,增强了网络自适应网络规模变化的能力.     

复杂网络社团结构理论在电力调度网中的应用

随着电力调度网规模的不断扩大,电力分级调度网络的划分日益成为复杂难解的问题。本文以复杂网络理论为基础,构建电力调度网的复杂网络模型,通过计算网络节点介数,挖掘网络社团结构,进行电力分级调度拓扑结构构建,并采用了一个模拟的电力调度网进行实验验证,划分准确率达到100％,实验结果说明该方法是有效、可行的。     

5G+区块链网络分片技术

基于5G+区块链网络分片建模,仿真对比了保证分片网络可信和保证全网可信的两种网络分片方案的性能差异,分析了单点受控概率、分片可信度、分片数量、全网可信度等参数对分片规模、网络规模的影响,给出了在满足一定可信度条件下,区块链网络分片的最优规模,并提出一定网络规模下,区块链网络从保证分片网络可信向保证全网可信方案演进再向更大规模分片网络可信方案演进的路线。     

Dynamic routing network algorithm of low voltage based on link quality

Power distribution network is a dedicated transmission network for power. If you want to use it as communication network, the network traffic will become very complicated. Low voltage distribution network topology is very complex and quite different in different distribution network; and different load leave or input power line will cause a strong performance of channel variability. It is because of these features of low voltage distribution network that it difficult to networking and the network is easily destroyed. This paper presents a dynamic routing algorithm, based on link quality, to improve the reliability of low voltage distribution networks. The algorithm can eventually form an 8-layer structure of the tree topology, and can achieve network self-healing capabilities when the link is broken. The algorithm is suitable for a variety of network physical topology, and finally be able to form a tree structure, thus effectively improving the reliability and system flexibility of communication network. Through the simulation on NS2, we can see the feasibility and network self-healing of the algorithm.     

基于CC2430的无线传感器网络的实现

无线传感器网络是一项新兴的技术,具有广泛的应用领域。在简单介绍无线传感器网络的概念及其特点的基础上,着重讨论基于ZigBee技术和433 MHz无线射频技术的无线传感器网络的实现方法,包括无线传感器网络的硬件和软件设计。ZigBee是一种具有全球统一标准的自组织网状网,网络容量大、组网灵活。多个ZigBee网络的协调器节点通过433 MHz无线射频组成星型网,有效地扩大了传感器网络的地理覆盖范围。实验结果表明,网络节点及整体网络均获得了良好的性能,验证ZigBee是实现无线传感器网络的理想解决方案。     

一种适用于Ad Hoc K重组播网络的负载均衡路由算法

Ad Hoc网络是一个多跳的无基础设施网络,本文在分析Ad Hoc网络自身特点的基础上,引入了一种多组播业务并存的K重组播网络,这种网络相对传统的组播网络具有节省系统开销,降低能量消耗的优点.文中对K重组播网络中的节点连接度的不同变化情况进行了理论上的详细研究,并在此基础上设计了一种适用于K重组播网络的负载均衡路由算法.仿真结果表明该路由算法拥塞控制性能良好,并能显著提高组播业务的稳定性.本文提出的这种K重组播网络能够广泛的应用于许多实际通信场合.     

Passive filterless core networks based on advanced modulation and electrical compensation technologies

In this paper, the filterless optical network concept is presented and explored through a number of filterless solution examples. In the first part, the filterless network concept is presented and analyzed through a comparative case study. In the second part, the filterless network design problem is defined and a filterless network design tool based on metaheuristics is presented. In the third part of this presentation, filterless network solutions are proposed for a number of core network topologies and compared to active photonic network solutions from the point of view of cost and performance. The results show that cost-effective filterless solutions can be found for different network sizes and topologies. The results of a comparative study show that filterless networks represent a cost-effective and reliable alternative to active optical switching network solutions.     

Some results for inhomogeneous ladder network

A new method of calculation of chain matrix for tapered ladder network is presented. This network is a special case of inhomogeneous ladder network. The theory of homogeneous ladder network is a starting point for the calculation of a chain matrix for a tapered ladder network.     

DVB-RCS卫星互动网络的研究

DVB-RCS卫星互动网络,应用前景广阔。DVB-RCS标准是为了在单向的卫星广播网络中(DVB-S)实现双向互动网络而采纳的一系列技术规范,但标准中仅规定了空中接口,没有提到如何实现一个网络的MAC接入层。卫星网络的实现结构是其MAC接入层协议的重要组成部分。本文设计了一个DVB-RCS卫星互动网络的网络结构,重点解释了它的多址接入方式和资源分配方式,最后描述了它的入网过程。     

柳州电信cdma2000网络室分小区PN优化研究

近年来,中国电信在原中国联通CDMA网络基础上进行了大规模的网络升级和扩容,将CDMA 1x网络升级至cdma2000。在覆盖建设已基本完成的情况下,用户集中区域的室分网络建设和优化逐渐成为CDMA网络发展重点。其中,PN规划对cdma2000网络质量影响重大,是cdma2000网络优化中必不可少的一部分。本文基于以上背景,结合柳州cdma2000网络现状,分析和研究了现有cdma2000网络室分小区PN方案中PN资源紧张、同PN-Offset和邻PN-Offset干扰等问题,提出了一种PN规划优化方案,以减弱网络信号干扰、提高通信质量、打造高品质3G网络。     

一种由基本割集矩阵求网络图的方法

对于一个给定的网络图,可以确定对应的网络矩阵。同样,如果给定网络矩阵,也能够画出对应的网络图。本文讨论由基本割集矩阵求网络图的方法,该方法利用基本割集矩阵Q和降价关联矩阵A的关系,由Q得到A,进而画出对应的网络图。本文的讨论可供从事电路教学的教师参考。     

基于SDN架构的地址跳变技术研究

网络嗅探作为网络攻击的前奏,对于网络安全存在较大威胁。为增强网络本身的抗嗅探窃听能力,在移动目标防御网络的地址跳变技术的研究基础上提出了一种基于传输过程的地址跳变方案,主要思想是在SDN网络架构下,控制器通过为传输路由上交换机下发不同流表来实现IP地址的跳变。仿真结果表明,可以以较小的网络开销实现跳变机制,并使网络对于网络嗅探达到较高的防御能力。     

光传输网安全保护机制的研究

光传输网作为信息社会的主体承载体,其安全性能举足轻重.在分析了光传输网安全需求的基础上,结合现有安全策略,采用环网保护策略提升其安全性能.通过仿真实验验证了环网保护的优良特性,最后简单设计了多重环网保护方案,以进一步提高光传输网的安全性能.     

未来通信网络架构及演进方案

随着互联网的飞速发展,网络承载内容逐渐由以基于连接的信息交互为主的业务,转变为以内容分享为主（视频）的业务,网络传送大量冗余信息,造成非正常的大规模投资,且业务质量难以保障,迫切需要研究构建与业务发展匹配的网络。通过对内容分享连接关系和通信网络架构连接关系的研究,探究二维差时分发或三维分发等实现方式,改造CDN构建内容边缘节点,优化调整核心网、无线网、承载网架构和网元部署,并考虑引入卫星等天基网络,从而在现有通信网络上构建无标度小跳数网络,实现网络架构与内容分发的匹配。     

Performance trending for management of packet-switched networks

The objective in this paper is to develop and demonstrate the capability of applying modeling and simulation techniques to maintain the network integrity of a packet-switched network. Here a new technique called performance trending is presented, in which key network parameters are monitored and network failure is predicted. A typical packet-switched network is simulated to verify performance trending for network performance management.     

VPN技术在局域网中的应用

在信息技术迅速发展的今天,用户对网络服务、网络安全及其网络应用的要求也正越来越高,一种组网更加灵活、成本更低的虚拟专网（VPN）也由此应运而生。VPN技术是一种建立在互联网公共网络架构之上,以取代原有连接方式的标准广域网,并通过一定的技术手段以达到类似私有专网的数据安全传输。     

通过切换优化提升LTE网络质量的研究

连接态的移动性管理主要通过切换实现。LTE网络由于是同频组网,在同频切换失败或者不及时会导致同频邻小区电平大于服务小区的时候同频干扰加剧,网络质量下降。通过现网数据分析发现,在目前业务量不高的情况下,切换不合理已经成为除弱覆盖以外导致LTE网络质量下降的一个重要因素。本文通过现网数据及案例分析,提出了通过切换优化提升LTE网络质量的方法。     

Handwritten Digits Recognition With Subgroup Neural Network

1IntroductionInrecentyears,theneuralnetworktheoryhascausedgreatintheareaofpatternrecognition.Themainreasonisthattheneuralnetworkhasmanyattractiveadvantages,whencomparedtotheconventionalpatternrecognitionmethods.AmongthevariousneuralnetworkmodelsIthebackpr…     

Quantifying the effect of local interconnects on on-chip power distribution

Existing methods to analyze and optimize on-chip power distribution networks typically focus only on global power network modeled as a two-dimensional mesh. In practice, current is supplied to switching transistors through a local power network at the lower metal layers. The local power network is connected to a global network through a stack of vias. The effect of these vias and the resistance of the local power network are typically ignored when optimizing a power network and placing decoupling capacitors. By modeling the power distribution network as a three-dimensional mesh, the error due to ignoring via and local interconnect resistances is quantified. It is demonstrated that ignoring the local power network and vias can both underestimate (by up to 45%) or overestimate (by up to 50%) the effective resistance of a power distribution network. The error depends upon multiple parameters such as the width of local and global power lines and via resistance. A design space is also generated to indicate the valid width of local and global power lines where the target resistance is satisfied. It is shown that a wider global network can be used to obtain a narrower local network, providing additional flexibility in the physical design process since routability is an important concern at lower metal layers. At high via resistances, however, this approach causes significant increase in the width of a global power network, indicating the growing significance of local power network and vias.