As the technology of IP Fast Rerouting (FRR) become mature and the related methods and specifi cation such as RFC5286 accepted as standard, it is expected that IP FRR will be deployed gradually and will enhance the su...As the technology of IP Fast Rerouting (FRR) become mature and the related methods and specifi cation such as RFC5286 accepted as standard, it is expected that IP FRR will be deployed gradually and will enhance the survivability of IP network. This paper presents a different method for computing the Loop-free Alternate Interfaces. The new algorithm can be referred as "Next-Hop Cost Decrease (NHCD)" criterion. Compared with the RFC5286 LFA method, NHCD can handle both the simultaneous link failure and node failure, including multi-link failures. It has less computational complexity and can be used uniformly in the Traffi c Engineering and Network Recovery. However, NHCD is somewhat lower than the LFA method on recovery ratio of single link failure. After a formal description of NHCD criterion and a proof of loopfree alternates, the paper presents the simulation results of NHCD.展开更多
The routing algorithm is one of the important problems in the Ad hoc networks. The performances of the networks are heavily depended on the property of the routing algorithm. In this paper, we present a new loop-free ...The routing algorithm is one of the important problems in the Ad hoc networks. The performances of the networks are heavily depended on the property of the routing algorithm. In this paper, we present a new loop-free routing algorithm in the Ad hoc networks. By virtue of the correlation of routing information among neighbor nodes, the formation of the temporary loops during the topological changes can be prohibited. The new algorithm can avoid the waste of the wireless bandwidth, and accelerate the convergence of the routing during the network transitions.展开更多
基于AODV(Ad Hoc on demand distanceVector)提出了一种新的按需多径矢量路由协议模型TRND-AODV(TreeRoot Node Disjoint Ad-Hoc On Demand distance Vector),旨在增强路由的健壮性,增强网络对拓扑变化的适应能力。通过对AODV路由协议...基于AODV(Ad Hoc on demand distanceVector)提出了一种新的按需多径矢量路由协议模型TRND-AODV(TreeRoot Node Disjoint Ad-Hoc On Demand distance Vector),旨在增强路由的健壮性,增强网络对拓扑变化的适应能力。通过对AODV路由协议发现过程的修改,能够在源节点和目的节点间提供多条节点分离的无环链路。仿真结果表明,该协议模型能有效地减少路由开销、加快数据包的转发速度。展开更多
In 1988,the authors designed cholangiostomy and cholangioplasty with subcutaneous free blind je junal loop and applied it to 64 hepatolithiasis operations,the effects of the operations were satisfactory. The operation...In 1988,the authors designed cholangiostomy and cholangioplasty with subcutaneous free blind je junal loop and applied it to 64 hepatolithiasis operations,the effects of the operations were satisfactory. The operation proudure is as follows:incise and explore the extrahepatic bile duct,extrat the biliary stones and plastic operation at the biliary stenosis.Take a piece of 10cm free jejunum with mesentery for cholangiostomy or cholangioplasty,anastomose the distal end of jejunum and the extrahepatic duct,close proximal jejunal stump and fix it to the subcutaneous zone in the incision. 14 of the 64 cases were treated with drainage of biliary tract. After cholangionraphy, 12 of them were found with residual stones in extrahepatic bile duct and the stones were extracted through the subcutaneous blindjejunal loop, 11 cases were cured with a cure rate of 91. 66 %. The greatest advantage of the techniques is that they can simplify the treatment of postoperation residual or recurrent stones.展开更多
It is well known that today's inter-domain routing protocol, Border Gateway Protocol (BGP), converges slowly during network failures. Due to the distribution nature of Internet routing decisions and the rate-limit...It is well known that today's inter-domain routing protocol, Border Gateway Protocol (BGP), converges slowly during network failures. Due to the distribution nature of Internet routing decisions and the rate-limiting timer Minimum Route Advertisement Interval (MRAI) of BGP, unavoidable convergence latency is introduced in reaction to network changes. During the period of convergence temporarily routing table inconsistencies cause short-term routing blackholes and loops which result in widespread temporary burst packet loss. In this paper, we present ROute-Free Forwarding (ROFF) - a novel technique for packet delivering continuously during periods of convergence. With slightly modifications on IP packet header and BGP, route loops and blackholes can be avoided. Our preliminary evaluation demonstrates that ROFF succeeds in reducing the number of Autonomous Systems (ASes) which experience burst packet loss and the duration of packet loss.展开更多
应用化工系统分析理论中萨金特与威斯特伯格(R W H Ssrgent&A W W esterberg)的单元串搜索法和自由度分析法,对30万t/a大型凯洛格合成氨装置氨合成系统进行流程分块、再循环回路切割和单元设备计算排序,结果表明,当一定的原始设计...应用化工系统分析理论中萨金特与威斯特伯格(R W H Ssrgent&A W W esterberg)的单元串搜索法和自由度分析法,对30万t/a大型凯洛格合成氨装置氨合成系统进行流程分块、再循环回路切割和单元设备计算排序,结果表明,当一定的原始设计变量确定后,计算顺序中的每个单元设备(或选择的体系)的物料子问题的自由度均为0或小于0。该法既可避免复杂的物热联解并省去全系统的迭代收敛,又可应用序贯联立模块法进行物料平衡的模拟计算,使计算快速准确。展开更多
文摘As the technology of IP Fast Rerouting (FRR) become mature and the related methods and specifi cation such as RFC5286 accepted as standard, it is expected that IP FRR will be deployed gradually and will enhance the survivability of IP network. This paper presents a different method for computing the Loop-free Alternate Interfaces. The new algorithm can be referred as "Next-Hop Cost Decrease (NHCD)" criterion. Compared with the RFC5286 LFA method, NHCD can handle both the simultaneous link failure and node failure, including multi-link failures. It has less computational complexity and can be used uniformly in the Traffi c Engineering and Network Recovery. However, NHCD is somewhat lower than the LFA method on recovery ratio of single link failure. After a formal description of NHCD criterion and a proof of loopfree alternates, the paper presents the simulation results of NHCD.
文摘The routing algorithm is one of the important problems in the Ad hoc networks. The performances of the networks are heavily depended on the property of the routing algorithm. In this paper, we present a new loop-free routing algorithm in the Ad hoc networks. By virtue of the correlation of routing information among neighbor nodes, the formation of the temporary loops during the topological changes can be prohibited. The new algorithm can avoid the waste of the wireless bandwidth, and accelerate the convergence of the routing during the network transitions.
文摘基于AODV(Ad Hoc on demand distanceVector)提出了一种新的按需多径矢量路由协议模型TRND-AODV(TreeRoot Node Disjoint Ad-Hoc On Demand distance Vector),旨在增强路由的健壮性,增强网络对拓扑变化的适应能力。通过对AODV路由协议发现过程的修改,能够在源节点和目的节点间提供多条节点分离的无环链路。仿真结果表明,该协议模型能有效地减少路由开销、加快数据包的转发速度。
文摘In 1988,the authors designed cholangiostomy and cholangioplasty with subcutaneous free blind je junal loop and applied it to 64 hepatolithiasis operations,the effects of the operations were satisfactory. The operation proudure is as follows:incise and explore the extrahepatic bile duct,extrat the biliary stones and plastic operation at the biliary stenosis.Take a piece of 10cm free jejunum with mesentery for cholangiostomy or cholangioplasty,anastomose the distal end of jejunum and the extrahepatic duct,close proximal jejunal stump and fix it to the subcutaneous zone in the incision. 14 of the 64 cases were treated with drainage of biliary tract. After cholangionraphy, 12 of them were found with residual stones in extrahepatic bile duct and the stones were extracted through the subcutaneous blindjejunal loop, 11 cases were cured with a cure rate of 91. 66 %. The greatest advantage of the techniques is that they can simplify the treatment of postoperation residual or recurrent stones.
基金Supported by Major State Basic Research Development Program (973 Program) (No. 2007CB307102, No. 2007CB 307100)
文摘It is well known that today's inter-domain routing protocol, Border Gateway Protocol (BGP), converges slowly during network failures. Due to the distribution nature of Internet routing decisions and the rate-limiting timer Minimum Route Advertisement Interval (MRAI) of BGP, unavoidable convergence latency is introduced in reaction to network changes. During the period of convergence temporarily routing table inconsistencies cause short-term routing blackholes and loops which result in widespread temporary burst packet loss. In this paper, we present ROute-Free Forwarding (ROFF) - a novel technique for packet delivering continuously during periods of convergence. With slightly modifications on IP packet header and BGP, route loops and blackholes can be avoided. Our preliminary evaluation demonstrates that ROFF succeeds in reducing the number of Autonomous Systems (ASes) which experience burst packet loss and the duration of packet loss.
文摘应用化工系统分析理论中萨金特与威斯特伯格(R W H Ssrgent&A W W esterberg)的单元串搜索法和自由度分析法,对30万t/a大型凯洛格合成氨装置氨合成系统进行流程分块、再循环回路切割和单元设备计算排序,结果表明,当一定的原始设计变量确定后,计算顺序中的每个单元设备(或选择的体系)的物料子问题的自由度均为0或小于0。该法既可避免复杂的物热联解并省去全系统的迭代收敛,又可应用序贯联立模块法进行物料平衡的模拟计算,使计算快速准确。
