针对空间信息网络结构复杂、拓扑动态以及空间通信时延大等特点,提出了一种基于软件定义网络(Software Defined Networking,SDN)的空间信息网络架构。在该架构中,地面核心网作为骨干网,多种邻近卫星构成接入网,整个网络通过多域控制器...针对空间信息网络结构复杂、拓扑动态以及空间通信时延大等特点,提出了一种基于软件定义网络(Software Defined Networking,SDN)的空间信息网络架构。在该架构中,地面核心网作为骨干网,多种邻近卫星构成接入网,整个网络通过多域控制器与单域控制器协同控制的方式实现空间信息网络的统一组网。同时,针对空间信息网络拓扑动态变化易导致通信中断的特点,提出了基于星际光互联的多路径承载策略,并对该策略进行了系统仿真。仿真结果表明,相比于一般的保护策略,多路径承载策略具有更低的阻塞率,且随着该策略中保护级别系数的增加,网络的阻塞率也相应增大。展开更多
分布式移动管理(DMM,distributed mobility management)是解决移动切换问题的有效方法之一,因此,被认为是能够应用于卫星网络移动性管理的技术。提出了一种基于DMM的软件定义网络(SDN,software defined network)的分布式移动管理方案,...分布式移动管理(DMM,distributed mobility management)是解决移动切换问题的有效方法之一,因此,被认为是能够应用于卫星网络移动性管理的技术。提出了一种基于DMM的软件定义网络(SDN,software defined network)的分布式移动管理方案,来解决卫星网络中的流量重定向问题。与传统DMM应用场景即基于网络或基于终端不同,SDN-DMM方案在SDN控制器中实现位置管理和地址切换。因此,基于SDN的卫星网路分布式移动管理方案相比于传统的方案可以实现分组转发路径优化,并在网络开销和流量管理方面表现出显著的优势。展开更多
Dahurian larch growing in Daxing’an Mountains can be divided into two types according to the wood colour: one is red, the other is white. Based on the national standard of the "Testing methods for physical &...Dahurian larch growing in Daxing’an Mountains can be divided into two types according to the wood colour: one is red, the other is white. Based on the national standard of the "Testing methods for physical &mechanical properties of wood", the parameters of wood colour and physico-mechanical properties of the above two different woods were tested and analyzed.The result showed that the colour rational phenetic parameters, physico-mechanical properties and work abilities of thc two woods were quite different, combincd with the other morphological characteristics, they belong to intraspccific two different types of Dahurian larch. The white wood is superior to the red one as a valuable timber tree. Because the cocfficients of shrinkage, hardness and colour of both are different, they were mixed working in the past, inevitably there have been various defects in working. In order to overcome these defects, we propose that the departments of wood production, salesmen and consumers should use them differently according to their individual character.展开更多
文摘针对空间信息网络结构复杂、拓扑动态以及空间通信时延大等特点,提出了一种基于软件定义网络(Software Defined Networking,SDN)的空间信息网络架构。在该架构中,地面核心网作为骨干网,多种邻近卫星构成接入网,整个网络通过多域控制器与单域控制器协同控制的方式实现空间信息网络的统一组网。同时,针对空间信息网络拓扑动态变化易导致通信中断的特点,提出了基于星际光互联的多路径承载策略,并对该策略进行了系统仿真。仿真结果表明,相比于一般的保护策略,多路径承载策略具有更低的阻塞率,且随着该策略中保护级别系数的增加,网络的阻塞率也相应增大。
文摘分布式移动管理(DMM,distributed mobility management)是解决移动切换问题的有效方法之一,因此,被认为是能够应用于卫星网络移动性管理的技术。提出了一种基于DMM的软件定义网络(SDN,software defined network)的分布式移动管理方案,来解决卫星网络中的流量重定向问题。与传统DMM应用场景即基于网络或基于终端不同,SDN-DMM方案在SDN控制器中实现位置管理和地址切换。因此,基于SDN的卫星网路分布式移动管理方案相比于传统的方案可以实现分组转发路径优化,并在网络开销和流量管理方面表现出显著的优势。
文摘Dahurian larch growing in Daxing’an Mountains can be divided into two types according to the wood colour: one is red, the other is white. Based on the national standard of the "Testing methods for physical &mechanical properties of wood", the parameters of wood colour and physico-mechanical properties of the above two different woods were tested and analyzed.The result showed that the colour rational phenetic parameters, physico-mechanical properties and work abilities of thc two woods were quite different, combincd with the other morphological characteristics, they belong to intraspccific two different types of Dahurian larch. The white wood is superior to the red one as a valuable timber tree. Because the cocfficients of shrinkage, hardness and colour of both are different, they were mixed working in the past, inevitably there have been various defects in working. In order to overcome these defects, we propose that the departments of wood production, salesmen and consumers should use them differently according to their individual character.
