TD-LTE is the evolution system of TD-SCDMA system. Early in 2004 3GPP put forward the "Long Term Evolution" project based on the OFDM/FDMA core physical techniques with high qualities. While China Mobile and...TD-LTE is the evolution system of TD-SCDMA system. Early in 2004 3GPP put forward the "Long Term Evolution" project based on the OFDM/FDMA core physical techniques with high qualities. While China Mobile and several operators and vendors, both domestic and foreign,展开更多
The Chinese Academy of Science (CAS), the top national research hub for natural sciences, has always been committed itself to the national target of research and development (R&D) of new medicines. During the past...The Chinese Academy of Science (CAS), the top national research hub for natural sciences, has always been committed itself to the national target of research and development (R&D) of new medicines. During the past several decades, a great number of R&D achievements have been attained. During the period from 1986 to 1999, for example, 135 pharmacutical projects won prizes of the CAS awards for natural sciences, inventions and S&T progress (roughly ac-展开更多
Network virtualization(NV) is pushed forward by its proponents as a crucial attribute of next generation network, aiming at overcoming the gradual ossification of current networks, particularly to the worldwide Intern...Network virtualization(NV) is pushed forward by its proponents as a crucial attribute of next generation network, aiming at overcoming the gradual ossification of current networks, particularly to the worldwide Internet. Through virtualization, multiple customized virtual networks(VNs), requested by users, are allowed to coexist on the underlying substrate networks(SNs). In addition, the virtualization scheme contributes to sharing underlying physical resources simultaneously and seamlessly. However, multiple technical issues still stand in the way of NV successful implementation. One key technical issue is virtual network embedding(VNE), known as the resource allocation problem for NV. This paper conducts a survey of embedding algorithms for VNE problem. At first, the NV business model for VNE problem is presented. Then, the latest VNE problem description is presented. Main performance metrics for evaluating embedding algorithms are also involved. Afterwards, existing VNE algorithms are detailed, according to the novel proposed category approach. Next, key future research aspects of embedding algorithms are listed out. Finally, the paper is briefly concluded.展开更多
A measurement-device-independent quantum key distribution(MDI-QKD) method with an air-water channel is researched. In this method, the underwater vehicle and satellite are the legitimate parties, and the third party i...A measurement-device-independent quantum key distribution(MDI-QKD) method with an air-water channel is researched. In this method, the underwater vehicle and satellite are the legitimate parties, and the third party is at the airwater interface in order to simplify the unilateral quantum channel to water or air. Considering the condition that both unilateral transmission distance and transmission loss coefficient are unequal, a perfect model of the asymmetric channel is built. The influence of asymmetric channel on system loss tolerance and secure transmission distance is analyzed. The simulation results show that with the increase of the channel's asymmetric degree, the system loss tolerance will descend, one transmission distance will be reduced while the other will be increased. When the asymmetric coefficient of channel is between 0.068 and 0.171, MDI-QKD can satisfy the demand of QKD with an air-water channel, namely the underwater transmission distance and atmospheric transmission distance are not less than 60 m and 12 km, respectively.展开更多
文摘TD-LTE is the evolution system of TD-SCDMA system. Early in 2004 3GPP put forward the "Long Term Evolution" project based on the OFDM/FDMA core physical techniques with high qualities. While China Mobile and several operators and vendors, both domestic and foreign,
文摘The Chinese Academy of Science (CAS), the top national research hub for natural sciences, has always been committed itself to the national target of research and development (R&D) of new medicines. During the past several decades, a great number of R&D achievements have been attained. During the period from 1986 to 1999, for example, 135 pharmacutical projects won prizes of the CAS awards for natural sciences, inventions and S&T progress (roughly ac-
基金supported by the National Key Research and Development of China under Grant 2018YFC1314903the National Natural Science Foundation of China under Grant 61372124 and Grant 61427801
文摘Network virtualization(NV) is pushed forward by its proponents as a crucial attribute of next generation network, aiming at overcoming the gradual ossification of current networks, particularly to the worldwide Internet. Through virtualization, multiple customized virtual networks(VNs), requested by users, are allowed to coexist on the underlying substrate networks(SNs). In addition, the virtualization scheme contributes to sharing underlying physical resources simultaneously and seamlessly. However, multiple technical issues still stand in the way of NV successful implementation. One key technical issue is virtual network embedding(VNE), known as the resource allocation problem for NV. This paper conducts a survey of embedding algorithms for VNE problem. At first, the NV business model for VNE problem is presented. Then, the latest VNE problem description is presented. Main performance metrics for evaluating embedding algorithms are also involved. Afterwards, existing VNE algorithms are detailed, according to the novel proposed category approach. Next, key future research aspects of embedding algorithms are listed out. Finally, the paper is briefly concluded.
基金supported by the National Natural Science Foundation of China(No.61302099)
文摘A measurement-device-independent quantum key distribution(MDI-QKD) method with an air-water channel is researched. In this method, the underwater vehicle and satellite are the legitimate parties, and the third party is at the airwater interface in order to simplify the unilateral quantum channel to water or air. Considering the condition that both unilateral transmission distance and transmission loss coefficient are unequal, a perfect model of the asymmetric channel is built. The influence of asymmetric channel on system loss tolerance and secure transmission distance is analyzed. The simulation results show that with the increase of the channel's asymmetric degree, the system loss tolerance will descend, one transmission distance will be reduced while the other will be increased. When the asymmetric coefficient of channel is between 0.068 and 0.171, MDI-QKD can satisfy the demand of QKD with an air-water channel, namely the underwater transmission distance and atmospheric transmission distance are not less than 60 m and 12 km, respectively.
