社会机会网络由人携带的带有短距离通信接口的移动设备利用人的移动形成,其数据采用/存储-携带-转发0的模式进行传输,本文针对这类网络,提出了一种基于中间中心度的P2P查询算法(P2P Query based on Betweenness Centrality Forwarding,P...社会机会网络由人携带的带有短距离通信接口的移动设备利用人的移动形成,其数据采用/存储-携带-转发0的模式进行传输,本文针对这类网络,提出了一种基于中间中心度的P2P查询算法(P2P Query based on Betweenness Centrality Forwarding,PQBCF).节点的中间中心度描述了节点在信息传输转发过程中的参与度和重要度,PQBCF算法通过选择具有较大中间中心度的节点来实现信息的高效转发.仿真实验表明,与目前该研究领域的SF(Spray and Focus)等主流算法相比,PQBCF算法能够有效提高查询成功率,并降低查询延时.展开更多
Understanding how spatial scale influences commonly-observed effects of climate and soil texture on soil organic carbon （SOC） storage is important for accurately estimating the SOC pool at different scales. The rela...Understanding how spatial scale influences commonly-observed effects of climate and soil texture on soil organic carbon （SOC） storage is important for accurately estimating the SOC pool at different scales. The relationships among climate factors, soil texture and SOC density at the regional, provincial, city, and county scales were evaluated at both the soil surface （0-20 cm） and throughout the soil profile （0-100 cm） in the Northeast China uplands. We examined 1 022 profiles obtained from the Second National Soil Survey of China. The results indicated that the relationships between climate factors and SOC density generally weakened with decreasing spatial scale. The provincial scale was optimal to assess the relationship between climate factors and SOC density because regional differences among provinces were covered up at the regional scale. However, the relationship between soil texture and SOC density had no obvious trend with increasing scale and changed with temperature. There were great differences in the impacts of climate factors and soil texture on SOC density at different scales. Climate factors had a larger effect on SOC density than soil texture at the regional scale. Similar trends were seen in Heilongjiang and eastern Inner Mongolia at the provincial scale. But, soil texture had a greater effect on SOC density compared with climate factors in Jilin and Liaoning. At the city and county scales, the influence of soil texture on SOC density was more important than climate factors.展开更多
文摘社会机会网络由人携带的带有短距离通信接口的移动设备利用人的移动形成,其数据采用/存储-携带-转发0的模式进行传输,本文针对这类网络,提出了一种基于中间中心度的P2P查询算法(P2P Query based on Betweenness Centrality Forwarding,PQBCF).节点的中间中心度描述了节点在信息传输转发过程中的参与度和重要度,PQBCF算法通过选择具有较大中间中心度的节点来实现信息的高效转发.仿真实验表明,与目前该研究领域的SF(Spray and Focus)等主流算法相比,PQBCF算法能够有效提高查询成功率,并降低查询延时.
基金Supported by the National Natural Science Foundation of China (No.40921061)the National Basic Research Program (973 Program) of China (No.2007CB407206)the Frontier Project of the Chinese Academy of Sciences(No.ISSASIP0715)
文摘Understanding how spatial scale influences commonly-observed effects of climate and soil texture on soil organic carbon （SOC） storage is important for accurately estimating the SOC pool at different scales. The relationships among climate factors, soil texture and SOC density at the regional, provincial, city, and county scales were evaluated at both the soil surface （0-20 cm） and throughout the soil profile （0-100 cm） in the Northeast China uplands. We examined 1 022 profiles obtained from the Second National Soil Survey of China. The results indicated that the relationships between climate factors and SOC density generally weakened with decreasing spatial scale. The provincial scale was optimal to assess the relationship between climate factors and SOC density because regional differences among provinces were covered up at the regional scale. However, the relationship between soil texture and SOC density had no obvious trend with increasing scale and changed with temperature. There were great differences in the impacts of climate factors and soil texture on SOC density at different scales. Climate factors had a larger effect on SOC density than soil texture at the regional scale. Similar trends were seen in Heilongjiang and eastern Inner Mongolia at the provincial scale. But, soil texture had a greater effect on SOC density compared with climate factors in Jilin and Liaoning. At the city and county scales, the influence of soil texture on SOC density was more important than climate factors.
