In view of the limited theoretical research on the load model of initial support for horseshoe-shaped prefabrication,this study focuses on the Luochuan Tunnel on the Xi'an-Yan'an newly built railway as the res...In view of the limited theoretical research on the load model of initial support for horseshoe-shaped prefabrication,this study focuses on the Luochuan Tunnel on the Xi'an-Yan'an newly built railway as the research object to explore its load model,load characteristic curve,plastic zone,deformation,and critical thickness.Theoretical research and numerical analysis were conducted.The results indicate that under the same boundary conditions,the ultimate bearing capacity of the prefabricated assembly initial support is higher than that of the shotcrete initial support,resulting in larger ultimate deformation capacity of the prefabricated assembly initial support.Based on numerical calculations,the ultimate deformation and critical thickness of the prefabricated initial lining for single-and double-track railway tunnels are obtained when buried at depths of 200,500,and 900 m in rock masses of classes Ⅲ,Ⅳ,and Ⅴ.展开更多
In order to have a better support of differentiated service, we propose Priority-based mixed burst assembly, in which packets of different priorities are assembled in a burst with an assigned proportion, and the prior...In order to have a better support of differentiated service, we propose Priority-based mixed burst assembly, in which packets of different priorities are assembled in a burst with an assigned proportion, and the priorities are lined in an ascending order in a burst from head to tail. Simulation results show that the proposed scheme performs very well in terms of latency and packet loss probability.展开更多
This letter proposes a new burst assembly technique for supporting QoS in optical burst switching (OBS) networks. It consists of the adaptive-threshold burst assembly mechanism and QoS-based random offset-time scheme....This letter proposes a new burst assembly technique for supporting QoS in optical burst switching (OBS) networks. It consists of the adaptive-threshold burst assembly mechanism and QoS-based random offset-time scheme. The assembly mechanism, which is fit well to multi-class burst assembly, not only matches with IP QoS mechanism based on packet classification, and also utilizes fairly and efficiently assembly capacity. Based on token-bucket model and burst segment selective discard (BSSD), the offset-time scheme can smooth the traffic to support OBS QoS. The simulation results show that the technique can improve the performance in terms of packet loss probability (PLP).展开更多
基金Research Project of China Railway Engineering Equipment Group Co.,Ltd.,Grant/Award Number:Equipment Research Cooperation 2019-14Postdoctoral Science Fund,Grant/Award Number:043201027。
文摘In view of the limited theoretical research on the load model of initial support for horseshoe-shaped prefabrication,this study focuses on the Luochuan Tunnel on the Xi'an-Yan'an newly built railway as the research object to explore its load model,load characteristic curve,plastic zone,deformation,and critical thickness.Theoretical research and numerical analysis were conducted.The results indicate that under the same boundary conditions,the ultimate bearing capacity of the prefabricated assembly initial support is higher than that of the shotcrete initial support,resulting in larger ultimate deformation capacity of the prefabricated assembly initial support.Based on numerical calculations,the ultimate deformation and critical thickness of the prefabricated initial lining for single-and double-track railway tunnels are obtained when buried at depths of 200,500,and 900 m in rock masses of classes Ⅲ,Ⅳ,and Ⅴ.
基金This work is partially supported by the National Natural Science Foundation of China under contract 69990540.
文摘In order to have a better support of differentiated service, we propose Priority-based mixed burst assembly, in which packets of different priorities are assembled in a burst with an assigned proportion, and the priorities are lined in an ascending order in a burst from head to tail. Simulation results show that the proposed scheme performs very well in terms of latency and packet loss probability.
基金This work was supported by National Hi-Tech Research and Development Program of China (863 Program) under contract No. 2002AA122021.
文摘This letter proposes a new burst assembly technique for supporting QoS in optical burst switching (OBS) networks. It consists of the adaptive-threshold burst assembly mechanism and QoS-based random offset-time scheme. The assembly mechanism, which is fit well to multi-class burst assembly, not only matches with IP QoS mechanism based on packet classification, and also utilizes fairly and efficiently assembly capacity. Based on token-bucket model and burst segment selective discard (BSSD), the offset-time scheme can smooth the traffic to support OBS QoS. The simulation results show that the technique can improve the performance in terms of packet loss probability (PLP).
