电力信息系统等级保护实施浅谈

如何全面和整体地解决各行各业在信息化建设中的安全问题,是国内外信息安全界多年来一直关注的问题。电力信息系统是一个由人、信息系统、IT基础设施、信息、操作等组成的动态、交互的多域复杂大系统,它的安全是多因素和多维的。文章对电力信息系统等级保护工作的主要内容以及依照等级保护制度建立信息安全保障体系的思路进行了详细的介绍。     

浅议IP RAN组网架构及保护方式

随着社会经济与科学技术的高速发展,移动业务IP化的速度也逐渐加快,LTE在国内的热度越来越高,传统的单一业务、单一网络承载模式已经无法很好地满足人们的需要,运营商承载网都需要进行转型调整来面对严峻的挑战。如今国内很多运营商已经开展IP RAN综合承载网络的全面建设以适应变化的市场需求,IP RAN及承载业务的组建已成为社会的关注点之一。     

应用菲涅耳原理计算ILS下滑台保护区

仪表着陆系统下滑信标天线是通过地面反射作用形成引导飞机着陆的下滑面引导信号,反射面的反射性能直接影响下滑面的信号质量,本文通过应用菲涅耳原理对下滑信标天线反射面保护区进行了计算,可作为下滑台保护区确定的参考。     

An optimal protection and restoration scheme (OPARS) for optical networks

Protection and restoration are critical network design issues for optical networks since even a single failure for a short duration may result in huge data loss due to the large capacity of optical fibers. However, few studies have been done on these issues for optical burst switching (OBS) networks. Protection and restoration are essential mechanisms for guaranteeing more reliable traffic delivery services. But it is not easy to apply existing mechanisms to optical burst switching (OBS) networks due to its one-way reservation signaling and the statistical burst multiplexing. Thus, to achieve the high transmission performance and reliability simultaneously, unique properties of OBS must be considered in the design of protection scheme. In this paper, an optimal protection and restoration scheme (OPARS) has been introduced that not only optimizes the number of provisioned protection wavelengths adaptively based on the traffic load as well as the quality of service (QoS) requirements of bursts in high speed networks but also minimizes burst loss rates. In addition, the proposed scheme has been used as an efficient contention resolution technique. The simulation results verify that the proposed scheme improve the network resource and channel utilization while guaranteeing the targeted protection reliability and QoS requirements of bursts.     

一种适用于丢包信道的小波编码图像传输方案

该文提出一种适用于丢包信道的基于小波变换的可伸缩图像编码传输方案。该方案利用分层多描述编码来提高信源编码的容错性能,利用信道编码来提高系统整体的抗丢包性能,采用编码后率失真优化技术对信源编码进行优化。利用非系统的RS码对信源编码符号和信道编码符号进行重新排序,将分层多描述编码和信道编码进行了有效的结合。通过在编解码端采用相同的排序算法,来减少传输开销。仿真结果表明,该方案与现有的方案相比,提高了接收图像的质量,并且需要较少的传输开销。     

简谈静电对电子产品的影响及防护

介绍了静电影响电子产品质量的几种主要途径以及一些静电防护方法。     

Zinc Mediated Reactions in Organic Synthesis: Efficient Synthesis of Silyl Ethers under Mild Conditions

General and practical method for the synthesis of silyl ethers in the presence of zinc powder under mild conditions has been described.     

Protection Schemes for IP-over-WDM Networks: Throughput and Recovery Time Comparison

This article presents a novel protection approach using Generalized Multi-Protocol Label Switching (GMPLS). This strategy provides protection at the Wavelength Division Multiplexing (WDM) layer, meaning that all Internet Protocol Label-Switched Path (IP LSPs) nested inside a lightpath are protected in an aggregated way. It uses resources efficiently since spare capacity of working primary lightpaths can be used for backup purposes whenever necessary. The IP and WDM layers are treated together as a single integrated network from a control plane point of view, so that network state information from both layers can be used. Besides discussing the strategy proposed and the key features of GMPLS that will allow its implementation, we mathematically formulate the maximum throughput problem. Thereafter, we propose and compare heuristic algorithms for IP-over-WDM networks using three protection approaches: WDM lightpath protection, IP LSP protection, and the proposed protection scheme. Their throughputs and recovery times are analyzed and compared. Our results show that, for a representative mesh network, the proposed aggregated protection scheme presents better protection efficiency and good scalability properties when compared with the other two schemes.     

A new protection algorithm with consideration of lightpath load in fault-tolerant GMPLS optical networks

In this paper, we study the survivability in GMPLS optical networks and propose a new algorithm called Protection based on Lightpath Load (PLL) to tolerate the single-fiber link failure. Based on the parameter, Boundary of Heavy-load Lightpath (BHL), PLL can effectively choose the protection execution whether on optical layer or on IP/MPLS layer, such that the bandwidth utilization and recovery complexity can be compromised. In PLL, if the number of Working Label Switching Path (WLSPs) carried on a Working Lightpath (WLP) exceeds the value of BHL, this WLP will be protected in optical layer; otherwise, these WLSPs carried on this WLP will be protected on IP/MPLS layer. Simulation results show that, compared to conventional protection algorithm, PLL not only can significantly reduce the recovery complexity but also can obtain satisfactory trade-off performance.     

大功率全固态广播发射机的综合防雷措施

文中对雷电的种类、分布规律及其入侵途径进行了介绍,说明了广播发送设备的雷电防护原理,结合实际工作情况详细阐述了大功率全固态广播发射机的防雷措施,说明了防霉维护检查应注意的事项。