一种面向空地一体化组网的体系架构

空间网络是空地一体化组网中地面网络延伸的重要组成部分。针对空间网络为移动星座的场景,传统的空地一体化组网模型将空间网络视为独立自治域,利用边界网关协议将空间网络与地面自治域互联起来,最大化同地面网络保持兼容。然而,传统组网模型存在边界网关面临频繁会话中断或大量路由更新等问题。通过重新审视空间网络的角色定位和边界划定问题,提出一种面向空地一体化组网的体系架构Slink。Slink的核心思想是空间网络为地面网络提供互联通道,利用星地网关隔离空地两网间的路由更新。实验仿真表明,Slink体系架构能够有效减小对空间路由器的路由存储空间需求,降低星地网络间的带宽消耗。     

基于CCD技术的外观纸病检测系统

设计了CCD在线外观纸病检测系统,介绍了该系统的硬件组成情况和系统的工作原理、技术指标和软件设计,重点阐述了外观纸病检测系统中CCD技术的优势。     

Performance comparison of reduced models for leak detection in water distribution networks

This paper presents a methodology for comparing the performance of model-reduction strategies to be used with a diagnostic methodology for leak detection in water distribution networks. The goal is to find reduction strategies that are suitable for error-domain model falsification, a model based data interpretation methodology. Twelve reduction strategies are derived from five strategy categories. Categories differ according to the manner in which nodes are selected for deletion. A node is selected for deletion according to: (1) the diameter of the pipes; (2) the number of pipes linked to a node; (3) the angle of the pipes in the case of two-pipe nodes; (4) the distribution of the water demand; and, (5) a pair-wise combination of some categories.The methodology is illustrated using part of a real network. Performance is evaluated first by judging the equivalency of the reduced network with the initial network (before the application of any reduction procedure) and secondly, by assessing the compatibility with the diagnostic methodology. The results show that for each reduction strategy the equivalency of networks is verified. Computational time can be reduced to less than 20% of the non-reduced network in the best case. Results of diagnostic performance show that the performance decreases when using reduced networks. The reduction strategy with the best diagnostic performance is that based on the angle of two-pipe nodes, with an angle threshold of 165°. In addition, the sensitivity of the performance of the reduced networks to variation in leak intensity is evaluated. Results show that the reduction strategies where the number of nodes is significantly reduced are the most sensitive.Finally this paper describes a Pareto analysis that is used to select the reduction strategy that is a good compromise between reduction of computational time and performance of the diagnosis. In this context, the extension strategy is the most attractive.     

基于改进FAHP的电力通信网可靠性评估方法研究

论文阐述了可靠性的一般评估方法,在借鉴TMN管理模型的基础上,对电力通信网可靠性进行了分层,构建了可靠性综合评估指标体系.为减少指标体系权重的主观性,提高评估结果的客观性和可信性,提出了一种改进的FAHP综合可靠性评估方法.该方法基于对数最小二乘法(LLSM)进行模糊权重计算,利用限位系数法来实现评估结果的解模糊过程,实例评估验证了该方法的有效性和可行性.最后对电力通信网可靠性的研究方向给出了建议.     

浅析网络异常流量分析检测研究与实现

伴随着互联网技术与网络业务的快速发展,网络规模逐渐扩大,网络运用开始逐步朝多元化、多样化以及复杂化的方向发展.现今,网络流量监测已经逐渐发展为计算机网络运用当中一个必不可少的内容与环节.文章将对网络异常流量加以说明,并对网络异常流量检测技术研究与实现进行分析与研究.     

探讨计算机网络专业学生的实训教学课程设置

计算机网络专业的学生的实训内容通常是与今后的工作相关联的,这种关联的程度越高,说明实训的效果越好,也可以从一个侧面说明教学越成功。所以,实训项目不应该是凭空设想的,也不应该是几年如一日的照搬照抄的,应该是符合市场需求的,与时俱进的。     

浅议网络体系结构与相关技术研究

随着高新科学技术的发展,互联网的规模也不断扩大.人们对互联网需求也越来越多,而现有的网络体系结构开始难以满足人们的需求.本文主要通过讨论现今网络体系结构存在的问题,对相关技术进行研究.     

Genetic algorithm‐based neural‐network modeling approach applied to AlGaN/GaN devices

An accurate equivalent circuit large‐signal model (ECLSM) for AlGaN‐GaN high electron mobility transistor (HEMT) is presented. The model is derived from a distributed small‐signal model that efficiently describes the physics of the device. A genetic neural‐network‐based model for the gate and drain currents and charges is presented along with its parameters extraction procedure. This model is embedded in the ECLSM, which is then implemented in CAD software and validated by pulsed and continuous large‐signal measurements of on‐wafer 8 × 125‐μm GaN on SiC substrate HEMT. Pulsed IV simulations show that the model can efficiently describe the bias dependency of trapping and self‐heating effects. Single‐ and two‐tone simulation results show that the model can accurately predict the output power and its harmonics and the associated intermodulation distortion (IMD) under different input‐power and bias conditions. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

赞比亚Lunzua水电站施工控制网的建立

文章结合工程实例,介绍南半球国家施工控制网的建立、平差与投影变形的解决方法.