针对用户端双WAN (wide area network)口路由器中并行业务引起的拥塞问题,提出基于P2P结构的多用户区域负载均衡的概念;在此基础上提出一种带宽租借策略,该策略根据用户端数据包到达率确定租借的带宽大小,通过租借带宽实现拥塞链路的迂...针对用户端双WAN (wide area network)口路由器中并行业务引起的拥塞问题,提出基于P2P结构的多用户区域负载均衡的概念;在此基础上提出一种带宽租借策略,该策略根据用户端数据包到达率确定租借的带宽大小,通过租借带宽实现拥塞链路的迂回,避免在不同网络运营商服务器间的网间链路传输业务;最后与目前主流的双WAN口路由器的流量均衡策略——会话(session)均衡策略进行性能对比仿真。仿真结果表明,基于区域负载均衡的带宽租借策略较session均衡策略时延降低14.99%,瓶颈链路的吞吐量提高24.48%。展开更多
Non-point-source pollution has become a major threat to the water quality of the Three Gorges Reservoir(TGR);however,nutrient loadings from terrestrial sources are unclear due to a lack of in situ monitoring.A represe...Non-point-source pollution has become a major threat to the water quality of the Three Gorges Reservoir(TGR);however,nutrient loadings from terrestrial sources are unclear due to a lack of in situ monitoring.A representative small watershed in the central part of the TGR area was selected to monitor the loss of nitrogen(N) and phosphorous(P) continuously along with the runoff from 2007 through 2009 to understand the exact sources and loadings.Results show that the non-point-source nitrogen and phosphorus comes mainly from the storm runoff from residential areas,citrus orchards and sloping croplands,which contributes up to 76% of the loadings in this watershed.Thus,a crucial measure for controlling non-point-source pollution is to intercept storm runoff from the three sources.Paddy fields provide a sink for non-point-source N and P by intercepting the runoff and sediment along with their different forms of nitrogen and phosphorus.The N and P removal efficiency by paddy fields from residential areas is within the range of 56% to 98%.Paddy fields are an important land-use option for reducing the non-point-source loading of N and P in the TGR area.展开更多
To slove the problems of constrained energy and unbalanced load of wireless sensor network(WSN)nodes,a multipath load balancing routing algorithm based on neighborhood subspace cooperation is proposed.The algorithm ad...To slove the problems of constrained energy and unbalanced load of wireless sensor network(WSN)nodes,a multipath load balancing routing algorithm based on neighborhood subspace cooperation is proposed.The algorithm adopts the improved particle swarm optimization(PSO)algorithm,takes the shortest distance and minimum energy consumption as optimization target and divides the nodes in one-hop neighborhood near the base station area into different regions.Furthermore,the algorithm designs a fitness function to find the best node in each region as a relay node and forward the data in parallel through the different paths of the relay nodes.The simulation results show that the proposed algorithm can reduce energy consumption and average end-to-end delay,balance network load and prolong network lifetime effectively.展开更多
文摘针对用户端双WAN (wide area network)口路由器中并行业务引起的拥塞问题,提出基于P2P结构的多用户区域负载均衡的概念;在此基础上提出一种带宽租借策略,该策略根据用户端数据包到达率确定租借的带宽大小,通过租借带宽实现拥塞链路的迂回,避免在不同网络运营商服务器间的网间链路传输业务;最后与目前主流的双WAN口路由器的流量均衡策略——会话(session)均衡策略进行性能对比仿真。仿真结果表明,基于区域负载均衡的带宽租借策略较session均衡策略时延降低14.99%,瓶颈链路的吞吐量提高24.48%。
基金supported by the National Science & Technology Pillar Program(Grant No. 2011BAD31B03)the Special Project on Water Pollution Control by the National Science & Technology Pillar Program(Grant No. 2009ZX07104-002)
文摘Non-point-source pollution has become a major threat to the water quality of the Three Gorges Reservoir(TGR);however,nutrient loadings from terrestrial sources are unclear due to a lack of in situ monitoring.A representative small watershed in the central part of the TGR area was selected to monitor the loss of nitrogen(N) and phosphorous(P) continuously along with the runoff from 2007 through 2009 to understand the exact sources and loadings.Results show that the non-point-source nitrogen and phosphorus comes mainly from the storm runoff from residential areas,citrus orchards and sloping croplands,which contributes up to 76% of the loadings in this watershed.Thus,a crucial measure for controlling non-point-source pollution is to intercept storm runoff from the three sources.Paddy fields provide a sink for non-point-source N and P by intercepting the runoff and sediment along with their different forms of nitrogen and phosphorus.The N and P removal efficiency by paddy fields from residential areas is within the range of 56% to 98%.Paddy fields are an important land-use option for reducing the non-point-source loading of N and P in the TGR area.
基金National Natural Science Foundation of China(No.11461038)Science and Technology Plan of Gansu Province(No.144NKCA040)
文摘To slove the problems of constrained energy and unbalanced load of wireless sensor network(WSN)nodes,a multipath load balancing routing algorithm based on neighborhood subspace cooperation is proposed.The algorithm adopts the improved particle swarm optimization(PSO)algorithm,takes the shortest distance and minimum energy consumption as optimization target and divides the nodes in one-hop neighborhood near the base station area into different regions.Furthermore,the algorithm designs a fitness function to find the best node in each region as a relay node and forward the data in parallel through the different paths of the relay nodes.The simulation results show that the proposed algorithm can reduce energy consumption and average end-to-end delay,balance network load and prolong network lifetime effectively.
