针对特殊地形或自然灾害对通信系统的影响,为提高信息传输有效性,建立基于空天地信息一体化的通信系统。针对该系统信息实时可靠传输的需求,为空天地信息一体化网络构建移动骨干网(mobile backbone network,MBN),MBN可有效简化路由,提...针对特殊地形或自然灾害对通信系统的影响,为提高信息传输有效性,建立基于空天地信息一体化的通信系统。针对该系统信息实时可靠传输的需求,为空天地信息一体化网络构建移动骨干网(mobile backbone network,MBN),MBN可有效简化路由,提高网络资源利用率,从而保证信息的实时可靠传输。提出了一种分布式MBN构建与维护(distributed mobile backbone network construction and maintenance,DMBNCM)算法。理论分析和仿真表明,DMBNCM算法构建的MBN是连通的,且消息和时间开销较小,对基于空天地信息一体化的通信系统有一定的应用前景。展开更多
近年来,金融、党政军类政企客户对低时延、硬通道专线业务需求旺盛,以高清视频、云计算、高品质专线为代表的新型电信业务兴起,尤其是高品质政企专线需求规模呈现快速扩大态势。随着同步数字体系(Synchronous Digital Hierarchy,SDH)逐...近年来,金融、党政军类政企客户对低时延、硬通道专线业务需求旺盛,以高清视频、云计算、高品质专线为代表的新型电信业务兴起,尤其是高品质政企专线需求规模呈现快速扩大态势。随着同步数字体系(Synchronous Digital Hierarchy,SDH)逐渐退出历史舞台,光传送网(Optical Transport Network,OTN)成为承载专线业务的关键技术。相较于传统的同步数字体系/多业务传送平台(Synchronous Digital Hierarchy/Multi Service Transport Platform,SDH/MSTP)网络,中国电信河南公司现有OTN网络在网络架构、覆盖范围、节点规模等方面存在不足,无法高效满足政企专线大带宽、低时延、高可靠、业务随选、快速开通业务的一体化承载需求。文章梳理中国电信河南公司OTN现状及面临挑战,重点针对OTN骨干网络进行专线业务承载分析,研究其关键技术及演进方向,并给出河南公司的部署方案和策略,实现政企OTN骨干网络架构的演进及平滑升级,打造高品质的专线承载网络。展开更多
近几年来,Internet 上频繁发生的蠕虫爆发和大规模分布式拒绝服务事件使网络服务的安全性面临严重的威胁。本文介绍了一个基于异常流量检测的 Internet 骨干网流量早期预警系统 ESTAB(Early-warning System ofTraffic Anomaly Based)。...近几年来,Internet 上频繁发生的蠕虫爆发和大规模分布式拒绝服务事件使网络服务的安全性面临严重的威胁。本文介绍了一个基于异常流量检测的 Internet 骨干网流量早期预警系统 ESTAB(Early-warning System ofTraffic Anomaly Based)。它基于 Internet 骨干网异常流量发现原理,通过对端口、长度分布、TCP 标志等直接变量(Direct Variable)的监测,并结合统计学中的时间序列分析方法,实时分析发现流量异常,并提出告警。文中提出了多种事件联合监测的概念,从流量监测角度有效地对付已知流量威胁(如已知蠕虫),并对未知流量威胁提供了相应的监测策略。展开更多
Over the past few decades,the Internet has rapidly diffused across China.The spread of the Internet has had a profound economic and social impact on Chinese rural areas.Existing research shows that Internet access sig...Over the past few decades,the Internet has rapidly diffused across China.The spread of the Internet has had a profound economic and social impact on Chinese rural areas.Existing research shows that Internet access significantly impacts agricultural production and improves smallholder farmers’income.Beyond these,the Internet can affect other dimensions of social welfare.However,research about the impact of Internet access on dietary quality in rural China remains scarce.This study utilizes multi-period panel data from Fixed Observation Point in rural China from 2009 to 2015 to estimate the impact of Internet access on dietary quality and food consumption of rural households and conducts a causal analysis.Regression models with time and household fixed effects allow robust estimation while reducing potential issues of unobserved heterogeneity.The estimates show that Internet access has significantly increased rural household dietary quality(measured by the Chinese Diet Balance Index).Further research finds that Internet access has increased the consumption of animal products,such as aquatic and dairy products.We also examine the underlying mechanisms.Internet access improves dietary quality and food consumption mainly through increasing household income and food expenditure.These results encourage the promotion of Internet access as a valuable tool for nutritional improvements,especially in rural areas.展开更多
文摘针对特殊地形或自然灾害对通信系统的影响,为提高信息传输有效性,建立基于空天地信息一体化的通信系统。针对该系统信息实时可靠传输的需求,为空天地信息一体化网络构建移动骨干网(mobile backbone network,MBN),MBN可有效简化路由,提高网络资源利用率,从而保证信息的实时可靠传输。提出了一种分布式MBN构建与维护(distributed mobile backbone network construction and maintenance,DMBNCM)算法。理论分析和仿真表明,DMBNCM算法构建的MBN是连通的,且消息和时间开销较小,对基于空天地信息一体化的通信系统有一定的应用前景。
文摘近年来,金融、党政军类政企客户对低时延、硬通道专线业务需求旺盛,以高清视频、云计算、高品质专线为代表的新型电信业务兴起,尤其是高品质政企专线需求规模呈现快速扩大态势。随着同步数字体系(Synchronous Digital Hierarchy,SDH)逐渐退出历史舞台,光传送网(Optical Transport Network,OTN)成为承载专线业务的关键技术。相较于传统的同步数字体系/多业务传送平台(Synchronous Digital Hierarchy/Multi Service Transport Platform,SDH/MSTP)网络,中国电信河南公司现有OTN网络在网络架构、覆盖范围、节点规模等方面存在不足,无法高效满足政企专线大带宽、低时延、高可靠、业务随选、快速开通业务的一体化承载需求。文章梳理中国电信河南公司OTN现状及面临挑战,重点针对OTN骨干网络进行专线业务承载分析,研究其关键技术及演进方向,并给出河南公司的部署方案和策略,实现政企OTN骨干网络架构的演进及平滑升级,打造高品质的专线承载网络。
文摘近几年来,Internet 上频繁发生的蠕虫爆发和大规模分布式拒绝服务事件使网络服务的安全性面临严重的威胁。本文介绍了一个基于异常流量检测的 Internet 骨干网流量早期预警系统 ESTAB(Early-warning System ofTraffic Anomaly Based)。它基于 Internet 骨干网异常流量发现原理,通过对端口、长度分布、TCP 标志等直接变量(Direct Variable)的监测,并结合统计学中的时间序列分析方法,实时分析发现流量异常,并提出告警。文中提出了多种事件联合监测的概念,从流量监测角度有效地对付已知流量威胁(如已知蠕虫),并对未知流量威胁提供了相应的监测策略。
基金This study was supported in part by the National Natural Science Foundation of China(71973136 and 72061147002)the 2115 Talent Development Program of China Agricultural University.
文摘Over the past few decades,the Internet has rapidly diffused across China.The spread of the Internet has had a profound economic and social impact on Chinese rural areas.Existing research shows that Internet access significantly impacts agricultural production and improves smallholder farmers’income.Beyond these,the Internet can affect other dimensions of social welfare.However,research about the impact of Internet access on dietary quality in rural China remains scarce.This study utilizes multi-period panel data from Fixed Observation Point in rural China from 2009 to 2015 to estimate the impact of Internet access on dietary quality and food consumption of rural households and conducts a causal analysis.Regression models with time and household fixed effects allow robust estimation while reducing potential issues of unobserved heterogeneity.The estimates show that Internet access has significantly increased rural household dietary quality(measured by the Chinese Diet Balance Index).Further research finds that Internet access has increased the consumption of animal products,such as aquatic and dairy products.We also examine the underlying mechanisms.Internet access improves dietary quality and food consumption mainly through increasing household income and food expenditure.These results encourage the promotion of Internet access as a valuable tool for nutritional improvements,especially in rural areas.
