Two kinds of controllable doped left-handed materials （DLHMs） were designed by inserting inductors and capacitors into the traditional left-handed material （LHM） as heterogeneous elements respectively, which are D...Two kinds of controllable doped left-handed materials （DLHMs） were designed by inserting inductors and capacitors into the traditional left-handed material （LHM） as heterogeneous elements respectively, which are DLHM with inductors （LDLHM） and DLHM with capacitors （CDLHM）. The characteristics of transmission spectrum were studied by using finite-difference time-domain method （FDTD）. Compared with the traditional LHM, the resonance strength of the LDLHM is weakened and the pass-band is narrowed, but with the increase of the value of the inserted inductors, the bandwidth is expanded. As capacitors inserted into the LHM, the pass-band of the CDLHM is expanded, but the pass-band is shifted to low frequency and the bandwidth is narrowed with the increase of the value of the capacitors, meanwhile, a new generated pass-band is also shifted to low frequency. Therefore, a quantized controllable doped left-handed material can be achieved.展开更多
By introducing a mobility anchor point （MAP）, hierarchical mobile IPv6 （HMIPv6） reduces the binding update signaling cost associated with mobile IPv6, but there still exist deficiencies. For instance, a mobile no...By introducing a mobility anchor point （MAP）, hierarchical mobile IPv6 （HMIPv6） reduces the binding update signaling cost associated with mobile IPv6, but there still exist deficiencies. For instance, a mobile node （MN） needs to orderly accomplish two binding updates with the MAP and home agent （HA） when the MN performs inter-MAP mobility. This results in a high signaling cost, thus affecting network performance. To reduce the inter-MAP binding update cost of idle MN in HMIPv6, an optimization scheme based on pointer forwarding with a threshold is proposed. The scheme can reduces the binding update cost of idle MN by using the binding update between MAP to replace several home binding updates. The signaling cost difference is derived by analyzing the cost of the basic scheme and the optimization scheme between two successive sessions. Simulation results show that, the optimization scheme can reduce the binding update signaling cost and improve the network performance as long as a suitable threshold is chosen. The discussions on the sensitivity of tele-parameters are also given.展开更多
基金supported by the National Natural Science Fundation of China (60871081)the Research Innovation Fund for College Students of Beijing University of Posts and Telecommunications (2010)the Beijing Natural Science Foundation (Design and Fabrication of Miniature Smart Antenna Based on Metamaterials,4112039)
文摘Two kinds of controllable doped left-handed materials （DLHMs） were designed by inserting inductors and capacitors into the traditional left-handed material （LHM） as heterogeneous elements respectively, which are DLHM with inductors （LDLHM） and DLHM with capacitors （CDLHM）. The characteristics of transmission spectrum were studied by using finite-difference time-domain method （FDTD）. Compared with the traditional LHM, the resonance strength of the LDLHM is weakened and the pass-band is narrowed, but with the increase of the value of the inserted inductors, the bandwidth is expanded. As capacitors inserted into the LHM, the pass-band of the CDLHM is expanded, but the pass-band is shifted to low frequency and the bandwidth is narrowed with the increase of the value of the capacitors, meanwhile, a new generated pass-band is also shifted to low frequency. Therefore, a quantized controllable doped left-handed material can be achieved.
基金supported by the Natural Science Foundation of Jiangsu Province (BK2009469)the Fundamental Research Funds for the Central Universities (BUPT2009RC0120)the National Natural Science Foundation of China (60772110)
文摘By introducing a mobility anchor point （MAP）, hierarchical mobile IPv6 （HMIPv6） reduces the binding update signaling cost associated with mobile IPv6, but there still exist deficiencies. For instance, a mobile node （MN） needs to orderly accomplish two binding updates with the MAP and home agent （HA） when the MN performs inter-MAP mobility. This results in a high signaling cost, thus affecting network performance. To reduce the inter-MAP binding update cost of idle MN in HMIPv6, an optimization scheme based on pointer forwarding with a threshold is proposed. The scheme can reduces the binding update cost of idle MN by using the binding update between MAP to replace several home binding updates. The signaling cost difference is derived by analyzing the cost of the basic scheme and the optimization scheme between two successive sessions. Simulation results show that, the optimization scheme can reduce the binding update signaling cost and improve the network performance as long as a suitable threshold is chosen. The discussions on the sensitivity of tele-parameters are also given.
