To evaluate transmission rate of highly dynamic space networks,a new method for studying space network capacity is proposed in this paper. Using graph theory,network capacity is defined as the maximum amount of flows ...To evaluate transmission rate of highly dynamic space networks,a new method for studying space network capacity is proposed in this paper. Using graph theory,network capacity is defined as the maximum amount of flows ground stations can receive per unit time. Combined with a hybrid constellation model,network capacity is calculated and further analyzed for practical cases. Simulation results show that network capacity will increase to different extents as link capacity,minimum ground elevation constraint and satellite onboard processing capability change. Considering the efficiency and reliability of communication networks,how to scientifically design satellite networks is also discussed.展开更多
Space information network is used for real time acquiring, transmitting and processing the space information on the space platform, which provides significant communication services for communication, navigation posit...Space information network is used for real time acquiring, transmitting and processing the space information on the space platform, which provides significant communication services for communication, navigation positioning and science exploration. In this paper, the architecture of Software Defined Space Optical Network (SDSON) based on cloud platform is designed by means of Software Defined Optical Network (SDON) and cloud services. The new architecture combining centralized and distributed management-control mechanism is a multi-layer and multi-domain architecture with powerful computing and storage ability. Moreover, reliable service and unreliable service communication models employed in the space information network are proposed considering the characteristic of Disruption/Delay Tolerant Network (DTN). Finally, the functional verification and demonstration are performed on our optical experimental network platform.展开更多
快速城市化加剧了社会发展与生态保护之间的矛盾,如何利用集约的资源要素实现社会-生态效益优化,是城市可持续发展的关键。以上海市中心城区为研究对象,基于多目标规划(multiple objective planning,MOP)模型设置效益目标函数和约束条...快速城市化加剧了社会发展与生态保护之间的矛盾,如何利用集约的资源要素实现社会-生态效益优化,是城市可持续发展的关键。以上海市中心城区为研究对象,基于多目标规划(multiple objective planning,MOP)模型设置效益目标函数和约束条件嵌入斑块生成土地利用变化模拟模型(patchgenerating land use simulation model,PLUS),实现多元目标下城市绿地生态网络多情景模拟及功能评价,以期为未来城市绿地生态网络高效构建、土地利用规划决策提供参考。结果表明:1)耦合MOP模型和PLUS模型,基于土地资源多效益目标的定量化求解,可以寻求社会-生态效益最优化的关键拐点;2)不同效益目标导向下,可持续发展情景较经济发展情景和生态保护情景,耕地、林地、水域等各用地类型的相互转化,以及经济发展和生态保护之间的关系均处于相对稳定状态;3)可持续发展情景的各项绿地生态网络测度指标均介于其他2个用地情景之间,重要斑块的数量及空间分布表征,在优化社会-生态效益、城市土地利用结构配置的同时,城市绿地生态网络功能也得到提升。研究成果为超大城市高密区绿地生态网络结构功能完善、土地利用规划科学决策、城市社会-生态系统综合效益提升提供科学参考。展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.6137110061001093+6 种基金61401118)the Natural Science Foundation of Shandong Province(Grant No.ZR2014FP016)the Natural Scientific Research Innovation Foundation in Harbin Institute of Technology(Grant No.HIT.NSRIF.2011114HIT.NSRIF.2013136HIT.NSRIF.2016100)the Scientific Research Foundation of Harbin Institute of Technology at Weihai(Grant No.HIT(WH)201409HIT(WH)201410)
文摘To evaluate transmission rate of highly dynamic space networks,a new method for studying space network capacity is proposed in this paper. Using graph theory,network capacity is defined as the maximum amount of flows ground stations can receive per unit time. Combined with a hybrid constellation model,network capacity is calculated and further analyzed for practical cases. Simulation results show that network capacity will increase to different extents as link capacity,minimum ground elevation constraint and satellite onboard processing capability change. Considering the efficiency and reliability of communication networks,how to scientifically design satellite networks is also discussed.
文摘Space information network is used for real time acquiring, transmitting and processing the space information on the space platform, which provides significant communication services for communication, navigation positioning and science exploration. In this paper, the architecture of Software Defined Space Optical Network (SDSON) based on cloud platform is designed by means of Software Defined Optical Network (SDON) and cloud services. The new architecture combining centralized and distributed management-control mechanism is a multi-layer and multi-domain architecture with powerful computing and storage ability. Moreover, reliable service and unreliable service communication models employed in the space information network are proposed considering the characteristic of Disruption/Delay Tolerant Network (DTN). Finally, the functional verification and demonstration are performed on our optical experimental network platform.
文摘快速城市化加剧了社会发展与生态保护之间的矛盾,如何利用集约的资源要素实现社会-生态效益优化,是城市可持续发展的关键。以上海市中心城区为研究对象,基于多目标规划(multiple objective planning,MOP)模型设置效益目标函数和约束条件嵌入斑块生成土地利用变化模拟模型(patchgenerating land use simulation model,PLUS),实现多元目标下城市绿地生态网络多情景模拟及功能评价,以期为未来城市绿地生态网络高效构建、土地利用规划决策提供参考。结果表明:1)耦合MOP模型和PLUS模型,基于土地资源多效益目标的定量化求解,可以寻求社会-生态效益最优化的关键拐点;2)不同效益目标导向下,可持续发展情景较经济发展情景和生态保护情景,耕地、林地、水域等各用地类型的相互转化,以及经济发展和生态保护之间的关系均处于相对稳定状态;3)可持续发展情景的各项绿地生态网络测度指标均介于其他2个用地情景之间,重要斑块的数量及空间分布表征,在优化社会-生态效益、城市土地利用结构配置的同时,城市绿地生态网络功能也得到提升。研究成果为超大城市高密区绿地生态网络结构功能完善、土地利用规划科学决策、城市社会-生态系统综合效益提升提供科学参考。
