IP定位是通过网络设备的IP地址推断其所在真实地理位置的一项关键技术。现有的研究主要针对端IP的定位,关于路由IP地理定位研究较少,且这些方法选取的网络特征较为单一,加上过于依赖探测节点和地标节点的位置和数量,导致路由定位结果理...IP定位是通过网络设备的IP地址推断其所在真实地理位置的一项关键技术。现有的研究主要针对端IP的定位,关于路由IP地理定位研究较少,且这些方法选取的网络特征较为单一,加上过于依赖探测节点和地标节点的位置和数量,导致路由定位结果理想化,难以应用到实际工作中。基于这些现状,提出了一种基于谱聚类的路由IP地理定位(Spectral Clustering Based Router IP Geolocation,SCRG)方法。该方法对目标IP进行网络路径探测,获取较为完整的网络路由拓扑信息;采用谱聚类算法对路由IP进行聚类,并将路径上的时延信息纳入到算法中,作为IP节点之间的距离;利用测量得到的自治域系统(Autonomous System,AS)路径信息对聚类簇做进一步划分与合并,并加入簇内投票冲突解决机制,尽可能避免出现路由环路的情况,将投票所在城市作为簇内路由IP的定位结果。对中国广东省IP的探测实验表明,该方法能够有效提高路由IP地理定位的正确率,降低错误投票对定位结果带来的影响,实现快速高效的大规模路由IP城市级地理定位。展开更多
In developing countries, land productivity involves little market, where the agricultural land use is mainly determined by the food demands as well as the land suitability. The land use pattern will not ensure everywh...In developing countries, land productivity involves little market, where the agricultural land use is mainly determined by the food demands as well as the land suitability. The land use pattern will not ensure everywhere enough land for certain cropping if spatial allocation just according to land use suitability. To solve this problem, a subzone and a pre-allocation for each land use are added in spatial allocation module, and land use suitability and area optimi- zation module are incorporated to constitute a whole agricultural land use optimal allocation （ALUOA） system. The system is developed on the platform .Net 2005 using ArcGIS Engine （version 9.2） and C# language, and is tested and validated in Yili watershed of Xinjiang Region on the newly reclaimed area. In the case study, with the help of soil data obtained from 69 points sampled in the fieldwork in 2008, main river data supplied by the Department of Water Resources of Xinjiang Uygur Autonomous Region in China, and temperature data provided by Data Center for Resources and Environmental Sciences, Chinese Academy of Sciences, land use suitability on eight common crops are evaluated one by one using linear weighted summation method in the land use suitability model. The linear pro- gramming （LP） model in area optimization model succeeds to give out land area target of each crop under three scenarios. At last, the land use targets are allotted in space both with a six subzone file and without a subzone file. The resuits show that the land use maps with a subzone not only ensure every part has enough land for every crop, but also gives a more fragmental land use pattern, with about 87.99% and 135.92% more patches than the one without, while at the expense of loss between 15.30% and 19.53% in the overall suitability at the same time.展开更多
文摘IP定位是通过网络设备的IP地址推断其所在真实地理位置的一项关键技术。现有的研究主要针对端IP的定位,关于路由IP地理定位研究较少,且这些方法选取的网络特征较为单一,加上过于依赖探测节点和地标节点的位置和数量,导致路由定位结果理想化,难以应用到实际工作中。基于这些现状,提出了一种基于谱聚类的路由IP地理定位(Spectral Clustering Based Router IP Geolocation,SCRG)方法。该方法对目标IP进行网络路径探测,获取较为完整的网络路由拓扑信息;采用谱聚类算法对路由IP进行聚类,并将路径上的时延信息纳入到算法中,作为IP节点之间的距离;利用测量得到的自治域系统(Autonomous System,AS)路径信息对聚类簇做进一步划分与合并,并加入簇内投票冲突解决机制,尽可能避免出现路由环路的情况,将投票所在城市作为簇内路由IP的定位结果。对中国广东省IP的探测实验表明,该方法能够有效提高路由IP地理定位的正确率,降低错误投票对定位结果带来的影响,实现快速高效的大规模路由IP城市级地理定位。
基金Under the auspices of National Natural Science Foundation of China (No. 41001108, 41071065)Beijing Municipal Natural Science Foundation (No. 9113029)
文摘In developing countries, land productivity involves little market, where the agricultural land use is mainly determined by the food demands as well as the land suitability. The land use pattern will not ensure everywhere enough land for certain cropping if spatial allocation just according to land use suitability. To solve this problem, a subzone and a pre-allocation for each land use are added in spatial allocation module, and land use suitability and area optimi- zation module are incorporated to constitute a whole agricultural land use optimal allocation （ALUOA） system. The system is developed on the platform .Net 2005 using ArcGIS Engine （version 9.2） and C# language, and is tested and validated in Yili watershed of Xinjiang Region on the newly reclaimed area. In the case study, with the help of soil data obtained from 69 points sampled in the fieldwork in 2008, main river data supplied by the Department of Water Resources of Xinjiang Uygur Autonomous Region in China, and temperature data provided by Data Center for Resources and Environmental Sciences, Chinese Academy of Sciences, land use suitability on eight common crops are evaluated one by one using linear weighted summation method in the land use suitability model. The linear pro- gramming （LP） model in area optimization model succeeds to give out land area target of each crop under three scenarios. At last, the land use targets are allotted in space both with a six subzone file and without a subzone file. The resuits show that the land use maps with a subzone not only ensure every part has enough land for every crop, but also gives a more fragmental land use pattern, with about 87.99% and 135.92% more patches than the one without, while at the expense of loss between 15.30% and 19.53% in the overall suitability at the same time.
