Network virtualization is recognized as an effective way to overcome the ossification of the Internet. However, the virtual network mapping problem (VNMP) is a critical challenge, focusing on how to map the virtual ne...Network virtualization is recognized as an effective way to overcome the ossification of the Internet. However, the virtual network mapping problem (VNMP) is a critical challenge, focusing on how to map the virtual networks to the substrate network with efficient utilization of infrastructure resources. The problem can be divided into two phases: node mapping phase and link mapping phase. In the node mapping phase, the existing algorithms usually map those virtual nodes with a complete greedy strategy, without considering the topology among these virtual nodes, resulting in too long substrate paths (with multiple hops). Addressing this problem, we propose a topology awareness mapping algorithm, which considers the topology among these virtual nodes. In the link mapping phase, the new algorithm adopts the k-shortest path algorithm. Simulation results show that the new algorithm greatly increases the long-term average revenue, the acceptance ratio, and the long-term revenue-to-cost ratio (R/C).展开更多
It is an effective method to broadcast the augmentation information of satellite navigation system using GEO technology.However,it becomes difficult to receive GEO signal in some special situation,for example in citie...It is an effective method to broadcast the augmentation information of satellite navigation system using GEO technology.However,it becomes difficult to receive GEO signal in some special situation,for example in cities or canyons,in which the signal will be sheltered by big buildings or mountains.In order to solve this problem,an Internet-based broadcast network has been proposed to utilize the infrastructure of the Internet to broadcast the augmentation information of satellite navigation system,which is based on application-layer multicast protocols.In this paper,a topology and position aware overlay network construction protocol is proposed to build the network for augmentation information of satellite navigation system.Simulation results show that the new algorithm is able to achieve better performance in terms of delay,depth and degree utilization.展开更多
Energy efficiency has become one of the most important issues in wireless body area network(WBAN).In this paper,an energy-efficient medium access control(MAC)protocol for WBAN is proposed based on human body posture u...Energy efficiency has become one of the most important issues in wireless body area network(WBAN).In this paper,an energy-efficient medium access control(MAC)protocol for WBAN is proposed based on human body posture under walking scenery.Due to person's movements,WBAN is a dynamic network,which means that traditional static protocols are no more suitable for it.For solving this problem,firstly,the feature of human walking at a constant speed is analyzed and we divide a spell of movements into a sequence of key frames just like a video constituted by numbers of continuous frames.As a result,the dynamic walking process is translated into several static postures,which the static MAC protocol could be used for.Secondly,concerning the performance of network lifetime,we design a posture-aware approach for lifetime maximization(PA-DPLM).With analytical and simulation results provided,we demonstrate that PA-DPLM protocol is energy-efficient and can be used under constant speed walking scenery.展开更多
基金supported by the National Basic Research Program (973) of China (No. 2011CB302601)the National Natural Science Foundation of China (No. 90818028)the National High-Tech R&D Program (863) of China (No. 2007AA010301)
文摘Network virtualization is recognized as an effective way to overcome the ossification of the Internet. However, the virtual network mapping problem (VNMP) is a critical challenge, focusing on how to map the virtual networks to the substrate network with efficient utilization of infrastructure resources. The problem can be divided into two phases: node mapping phase and link mapping phase. In the node mapping phase, the existing algorithms usually map those virtual nodes with a complete greedy strategy, without considering the topology among these virtual nodes, resulting in too long substrate paths (with multiple hops). Addressing this problem, we propose a topology awareness mapping algorithm, which considers the topology among these virtual nodes. In the link mapping phase, the new algorithm adopts the k-shortest path algorithm. Simulation results show that the new algorithm greatly increases the long-term average revenue, the acceptance ratio, and the long-term revenue-to-cost ratio (R/C).
基金supported by National High Technical Research and Development Program of China (863 Program) under Grant No. 2009AA12Z322
文摘It is an effective method to broadcast the augmentation information of satellite navigation system using GEO technology.However,it becomes difficult to receive GEO signal in some special situation,for example in cities or canyons,in which the signal will be sheltered by big buildings or mountains.In order to solve this problem,an Internet-based broadcast network has been proposed to utilize the infrastructure of the Internet to broadcast the augmentation information of satellite navigation system,which is based on application-layer multicast protocols.In this paper,a topology and position aware overlay network construction protocol is proposed to build the network for augmentation information of satellite navigation system.Simulation results show that the new algorithm is able to achieve better performance in terms of delay,depth and degree utilization.
基金supported by the National Natural Science Foundation of China(No.61074165 and No.61273064)Jilin Provincial Science & Technology Department Key Scientific and Technological Project(No.20140204034GX)Jilin Province Development and Reform Commission Project(No.2015Y043)
文摘Energy efficiency has become one of the most important issues in wireless body area network(WBAN).In this paper,an energy-efficient medium access control(MAC)protocol for WBAN is proposed based on human body posture under walking scenery.Due to person's movements,WBAN is a dynamic network,which means that traditional static protocols are no more suitable for it.For solving this problem,firstly,the feature of human walking at a constant speed is analyzed and we divide a spell of movements into a sequence of key frames just like a video constituted by numbers of continuous frames.As a result,the dynamic walking process is translated into several static postures,which the static MAC protocol could be used for.Secondly,concerning the performance of network lifetime,we design a posture-aware approach for lifetime maximization(PA-DPLM).With analytical and simulation results provided,we demonstrate that PA-DPLM protocol is energy-efficient and can be used under constant speed walking scenery.
