通过对中波频段的特性分析,提出一种创新的中波应急广播覆盖网构建方案。基于信号传播理论和通信工程原理,结合地理信息系统(Geographic Information System,GIS)技术,优化中波发射台布局,提高应急广播信号的覆盖范围和稳定性。采用先...通过对中波频段的特性分析,提出一种创新的中波应急广播覆盖网构建方案。基于信号传播理论和通信工程原理,结合地理信息系统(Geographic Information System,GIS)技术,优化中波发射台布局,提高应急广播信号的覆盖范围和稳定性。采用先进的调制解调技术和功率控制策略,有效克服信道传播中的多径效应和信号衰减,提升应急广播系统的抗干扰性。通过在不同地理环境下的仿真实验,验证所提出构建方案的可行性和效果,为中波应急广播系统的建设提供有力的技术支持,为应对突发事件提供可靠的通信保障。展开更多
Aiming to analyze the damage mechanism of UTAO from the perspective of meso-mechanical mechanism using discrete element method(DEM),we conducted study of diseases problems of UTAO in several provinces in China,and fou...Aiming to analyze the damage mechanism of UTAO from the perspective of meso-mechanical mechanism using discrete element method(DEM),we conducted study of diseases problems of UTAO in several provinces in China,and found that aggregate spalling was one of the main disease types of UTAO.A discrete element model of UTAO pavement structure was constructed to explore the meso-mechanical mechanism of UTAO damage under the influence of layer thickness,gradation,and bonding modulus.The experimental results show that,as the thickness of UTAO decreasing,the maximum value and the mean value of the contact force between all aggregate particles gradually increase,which leads to aggregates more prone to spalling.Compared with OGFC-5 UTAO,AC-5 UTAO presents smaller maximum and average values of all contact forces,and the loading pressure in AC-5 UTAO is fully diffused in the lateral direction.In addition,the increment of pavement modulus strengthens the overall force of aggregate particles inside UTAO,resulting in aggregate particles peeling off more easily.The increase of bonding modulus changes the position where the maximum value of the tangential force appears,whereas has no effect on the normal force.展开更多
部署于云服务传递网络(Cloud Service Delivery Network,CSDN)基础设施的P2P VoD系统,在每个CSDN节点内将同一节目的所有用户构建成P2P覆盖网,但CSDN单节点内大量节目的并发用户稀少.因此,如何在兼顾流量本地化的前提下,解决CSDN架构下P...部署于云服务传递网络(Cloud Service Delivery Network,CSDN)基础设施的P2P VoD系统,在每个CSDN节点内将同一节目的所有用户构建成P2P覆盖网,但CSDN单节点内大量节目的并发用户稀少.因此,如何在兼顾流量本地化的前提下,解决CSDN架构下P2P VoD覆盖网构造中Peer资源稀疏问题是当前面临的一个挑战.为此,提出一种P2P覆盖网的弹性构造方法ECM(Elastic Construction Method).ECM依据资源索引来弹性扩展P2P覆盖网的构造范围,有效解决Peer资源稀疏问题;同时根据CSDN节点间距离来选择扩展路径,实现P2P流量本地化.最后模拟实验结果表明,ECM能有效均衡服务器负载和跨ISP流量.展开更多
文摘通过对中波频段的特性分析,提出一种创新的中波应急广播覆盖网构建方案。基于信号传播理论和通信工程原理,结合地理信息系统(Geographic Information System,GIS)技术,优化中波发射台布局,提高应急广播信号的覆盖范围和稳定性。采用先进的调制解调技术和功率控制策略,有效克服信道传播中的多径效应和信号衰减,提升应急广播系统的抗干扰性。通过在不同地理环境下的仿真实验,验证所提出构建方案的可行性和效果,为中波应急广播系统的建设提供有力的技术支持,为应对突发事件提供可靠的通信保障。
文摘Aiming to analyze the damage mechanism of UTAO from the perspective of meso-mechanical mechanism using discrete element method(DEM),we conducted study of diseases problems of UTAO in several provinces in China,and found that aggregate spalling was one of the main disease types of UTAO.A discrete element model of UTAO pavement structure was constructed to explore the meso-mechanical mechanism of UTAO damage under the influence of layer thickness,gradation,and bonding modulus.The experimental results show that,as the thickness of UTAO decreasing,the maximum value and the mean value of the contact force between all aggregate particles gradually increase,which leads to aggregates more prone to spalling.Compared with OGFC-5 UTAO,AC-5 UTAO presents smaller maximum and average values of all contact forces,and the loading pressure in AC-5 UTAO is fully diffused in the lateral direction.In addition,the increment of pavement modulus strengthens the overall force of aggregate particles inside UTAO,resulting in aggregate particles peeling off more easily.The increase of bonding modulus changes the position where the maximum value of the tangential force appears,whereas has no effect on the normal force.
文摘部署于云服务传递网络(Cloud Service Delivery Network,CSDN)基础设施的P2P VoD系统,在每个CSDN节点内将同一节目的所有用户构建成P2P覆盖网,但CSDN单节点内大量节目的并发用户稀少.因此,如何在兼顾流量本地化的前提下,解决CSDN架构下P2P VoD覆盖网构造中Peer资源稀疏问题是当前面临的一个挑战.为此,提出一种P2P覆盖网的弹性构造方法ECM(Elastic Construction Method).ECM依据资源索引来弹性扩展P2P覆盖网的构造范围,有效解决Peer资源稀疏问题;同时根据CSDN节点间距离来选择扩展路径,实现P2P流量本地化.最后模拟实验结果表明,ECM能有效均衡服务器负载和跨ISP流量.
