On the basis of integrating two-dimensional varying thickness finite elementmethod with hybrid genetic algorithm, a precise model was developed to design ideal backup rollcontour (Varying Contact Backup Roll, in short...On the basis of integrating two-dimensional varying thickness finite elementmethod with hybrid genetic algorithm, a precise model was developed to design ideal backup rollcontour (Varying Contact Backup Roll, in short VCR) in finishing rains of hot rolling rapidly andefficaciously. Additionally, a lot of good actual effects of VCR, such as evident improvement ofprofile and flatness of strip, remarkable decrease of roll consume, excellent maneuverability andmaintenance, and so on, were validated by long-term industrial tests in hot rolling strip plant ofWuhan Iron and Steel Group Corporation (WISCO).展开更多
Software for calculating the strip profile in 4-high hot rolling mill was developed using influence coefficient method. Regularity of backup roller diameter effect rate was studied systematically using the software. T...Software for calculating the strip profile in 4-high hot rolling mill was developed using influence coefficient method. Regularity of backup roller diameter effect rate was studied systematically using the software. The results show that backup roller diameter effect rates decrease versus the increase of strip width, increase significantly versus the increase of backup roller diameter and obscurely increase versus the increase of reduction. The difference between backup roller diameter effect rate and it is reference value increases versus strip width increasing. When backup rollers diameter is set to be 1.64 m and strip width is 1.85 m, the error of strip profile calculated using the model of backup roller diameter effect rate reference value will be 3.55μm. Based on the results, reference values of roller diameter effect rate and six power polynomial fitting coefficients of modification coefficients were determined considering coherent parameters. The high precision model of backup roller diameter effect rate was established. When the model is used to predict strip profile, the accuracy is less than 5.0 μm.展开更多
为提高企业网络环境的安全性和稳定性,使用防火墙双机热备技术进行网络安全策略配置。整个网络采用接入层、汇聚层、核心层的3层拓扑结构进行架构,利用VLAN(虚拟局域网,Virtual Local Area Network,简称VLAN)技术进行地址配置,采用trun...为提高企业网络环境的安全性和稳定性,使用防火墙双机热备技术进行网络安全策略配置。整个网络采用接入层、汇聚层、核心层的3层拓扑结构进行架构,利用VLAN(虚拟局域网,Virtual Local Area Network,简称VLAN)技术进行地址配置,采用trunk模式配置接入层,由两台交换机汇聚接入层流量,采用MSTP(多生成树协议,Multiple Spanning Tree Protocol,简称MSTP)解决环路问题,采用VRRP(虚拟路由冗余协议,Virtual Router Redundancy Protocol,简称VRRP)提高网络的可靠性,核心层使用两台防火墙,配置OSPF协议(开放式最短路径优先协议,Open Shortest Path First,简称OSPF)。内外网连通性测试和模拟宕机测试结果表明,防火墙双机热备技术能使企业网络环境更高效、稳定、安全。展开更多
多控制器软件定义网络中交换机迁移策略计算空间大、考虑因素单一且无法立刻迁移出故障域内交换机.对此,本文将原交换机迁移问题优化成为控制器的热备份及选举问题(Controller Hot Backup and Election Problem,CHBE Problem),对控制器...多控制器软件定义网络中交换机迁移策略计算空间大、考虑因素单一且无法立刻迁移出故障域内交换机.对此,本文将原交换机迁移问题优化成为控制器的热备份及选举问题(Controller Hot Backup and Election Problem,CHBE Problem),对控制器进行热备份,并设计相应的备份空间确定算法和主控制器选举算法,通过权衡信息交互、失联性、负载失衡和跨域通信四种代价实现合理的网络构建.实验结果表明,与现有算法相比,负载均衡程度和跨域通信问题改善明显,备份空间平均缩小了65%;在OS3E拓扑中加权后的综合评价最高提升了71%.展开更多
基金[The word was financially supported by "973" key foundation of China (No. 95-527-01-02-04). ]
文摘On the basis of integrating two-dimensional varying thickness finite elementmethod with hybrid genetic algorithm, a precise model was developed to design ideal backup rollcontour (Varying Contact Backup Roll, in short VCR) in finishing rains of hot rolling rapidly andefficaciously. Additionally, a lot of good actual effects of VCR, such as evident improvement ofprofile and flatness of strip, remarkable decrease of roll consume, excellent maneuverability andmaintenance, and so on, were validated by long-term industrial tests in hot rolling strip plant ofWuhan Iron and Steel Group Corporation (WISCO).
基金the National Natu-ral Science Foundation of China,under the contract No.59995440the State Key Development Prograrmming Research under the contract No.G2000027208-4 the Natural Science Foundation ofLiaoning Province,under the contract No.2001101021.
文摘Software for calculating the strip profile in 4-high hot rolling mill was developed using influence coefficient method. Regularity of backup roller diameter effect rate was studied systematically using the software. The results show that backup roller diameter effect rates decrease versus the increase of strip width, increase significantly versus the increase of backup roller diameter and obscurely increase versus the increase of reduction. The difference between backup roller diameter effect rate and it is reference value increases versus strip width increasing. When backup rollers diameter is set to be 1.64 m and strip width is 1.85 m, the error of strip profile calculated using the model of backup roller diameter effect rate reference value will be 3.55μm. Based on the results, reference values of roller diameter effect rate and six power polynomial fitting coefficients of modification coefficients were determined considering coherent parameters. The high precision model of backup roller diameter effect rate was established. When the model is used to predict strip profile, the accuracy is less than 5.0 μm.
文摘为提高企业网络环境的安全性和稳定性,使用防火墙双机热备技术进行网络安全策略配置。整个网络采用接入层、汇聚层、核心层的3层拓扑结构进行架构,利用VLAN(虚拟局域网,Virtual Local Area Network,简称VLAN)技术进行地址配置,采用trunk模式配置接入层,由两台交换机汇聚接入层流量,采用MSTP(多生成树协议,Multiple Spanning Tree Protocol,简称MSTP)解决环路问题,采用VRRP(虚拟路由冗余协议,Virtual Router Redundancy Protocol,简称VRRP)提高网络的可靠性,核心层使用两台防火墙,配置OSPF协议(开放式最短路径优先协议,Open Shortest Path First,简称OSPF)。内外网连通性测试和模拟宕机测试结果表明,防火墙双机热备技术能使企业网络环境更高效、稳定、安全。
文摘多控制器软件定义网络中交换机迁移策略计算空间大、考虑因素单一且无法立刻迁移出故障域内交换机.对此,本文将原交换机迁移问题优化成为控制器的热备份及选举问题(Controller Hot Backup and Election Problem,CHBE Problem),对控制器进行热备份,并设计相应的备份空间确定算法和主控制器选举算法,通过权衡信息交互、失联性、负载失衡和跨域通信四种代价实现合理的网络构建.实验结果表明,与现有算法相比,负载均衡程度和跨域通信问题改善明显,备份空间平均缩小了65%;在OS3E拓扑中加权后的综合评价最高提升了71%.
