车载自组织网络(vehicular ad hoc networks,简称VANETs)具有网络间歇连通、节点高速移动及动态的网络拓扑结构等特性,如何有效地实现车辆间的数据传输,成为VANETs的重大挑战.现有研究工作基于历史交通流量或历史延迟预测路段当前交通...车载自组织网络(vehicular ad hoc networks,简称VANETs)具有网络间歇连通、节点高速移动及动态的网络拓扑结构等特性,如何有效地实现车辆间的数据传输,成为VANETs的重大挑战.现有研究工作基于历史交通流量或历史延迟预测路段当前交通状况的方法并不可靠.此外,要实现高效的数据路由传输,配置大量路边基础设施节点(deploying roadside unit,简称RSU)是一种可行方案,但通常需要额外开销.基于城市区域长时间拥有大量地上停放车辆这一事实,提出了基于停车骨干网络的数据传输策略PBBD(parking backbone based data delivery),不需要配置任何地面基础设施,而是把地面的停放车辆组成一个虚拟的停车覆盖网络,通过该停车覆盖网实现数据的传输.为此,首先,对于每一条道路,把路边和非路边停放车辆组成一个尽可能长的停车簇,并基于这些停车簇组织城市停车骨干网络.其次,设计基于停车覆盖网络的全新数据传输算法来实现车辆间的有效数据传输.基于真实城市地图和交通数据的模拟实验结果表明,与现有的几种数据传输算法相比,PBBD能够以较低的网络传输开销和较小的传输延迟获得较高的数据传输成功率.展开更多
提出一种在机会网络中基于周期性间歇连通的数据传输策略PICD(periodic intermittently connected-based data delivery in opportunistic networks).通过有效利用节点间的周期间歇连通性改善数据传输性能.节点传输概率的计算则充分考...提出一种在机会网络中基于周期性间歇连通的数据传输策略PICD(periodic intermittently connected-based data delivery in opportunistic networks).通过有效利用节点间的周期间歇连通性改善数据传输性能.节点传输概率的计算则充分考虑了其与汇聚点间存在的间歇多跳路径,并将其与消息容忍的传输延迟相结合.首先,采用随机动态规划的方法建立与延迟相关的传输概率模型;然后,通过基于多跳的函数空间迭代法求出一个周期内的与延迟相关的传输概率分布矩阵;节点面向不同消息延迟的传输概率则基于分布矩阵计算获得,以此作为选择下一跳的依据.与延迟相关的概率转发机制提高了消息在容忍的延迟内被成功递交的可能.仿真实验结果表明,与现有的几种数据传输算法相比,在节点具有循环运动特征的环境下,PICD具有较高的数据传输成功率和较低的递交延迟.展开更多
The low efficiency and high cost of fresh agricultural product terminal distribution directly restrict the operation of the entire supply network.To reduce costs and optimize the distribution network,we construct a mi...The low efficiency and high cost of fresh agricultural product terminal distribution directly restrict the operation of the entire supply network.To reduce costs and optimize the distribution network,we construct a mixed integer programmingmodel that comprehensively considers tominimize fixed,transportation,fresh-keeping,time,carbon emissions,and performance incentive costs.We analyzed the performance of traditional rider distribution and robot distribution modes in detail.In addition,the uncertainty of the actual market demand poses a huge threat to the stability of the terminal distribution network.In order to resist uncertain interference,we further extend the model to a robust counterpart form.The results of the simulation show that the instability of random parameters will lead to an increase in the cost.Compared with the traditional rider distribution mode,the robot distribution mode can save 12.7%on logistics costs,and the distribution efficiency is higher.Our research can provide support for the design of planning schemes for transportation enterprise managers.展开更多
Information-centric satellite networks play a crucial role in remote sensing applications,particularly in the transmission of remote sensing images.However,the occurrence of burst traffic poses significant challenges ...Information-centric satellite networks play a crucial role in remote sensing applications,particularly in the transmission of remote sensing images.However,the occurrence of burst traffic poses significant challenges in meeting the increased bandwidth demands.Traditional content delivery networks are ill-equipped to handle such bursts due to their pre-deployed content.In this paper,we propose an optimal replication strategy for mitigating burst traffic in information-centric satellite networks,specifically focusing on the transmission of remote sensing images.Our strategy involves selecting the most optimal replication delivery satellite node when multiple users subscribe to the same remote sensing content within a short time,effectively reducing network transmission data and preventing throughput degradation caused by burst traffic expansion.We formulate the content delivery process as a multi-objective optimization problem and apply Markov decision processes to determine the optimal value for burst traffic reduction.To address these challenges,we leverage federated reinforcement learning techniques.Additionally,we use bloom filters with subdivision and data identification methods to enable rapid retrieval and encoding of remote sensing images.Through software-based simulations using a low Earth orbit satellite constellation,we validate the effectiveness of our proposed strategy,achieving a significant 17%reduction in the average delivery delay.This paper offers valuable insights into efficient content delivery in satellite networks,specifically targeting the transmission of remote sensing images,and presents a promising approach to mitigate burst traffic challenges in information-centric environments.展开更多
文摘车载自组织网络(vehicular ad hoc networks,简称VANETs)具有网络间歇连通、节点高速移动及动态的网络拓扑结构等特性,如何有效地实现车辆间的数据传输,成为VANETs的重大挑战.现有研究工作基于历史交通流量或历史延迟预测路段当前交通状况的方法并不可靠.此外,要实现高效的数据路由传输,配置大量路边基础设施节点(deploying roadside unit,简称RSU)是一种可行方案,但通常需要额外开销.基于城市区域长时间拥有大量地上停放车辆这一事实,提出了基于停车骨干网络的数据传输策略PBBD(parking backbone based data delivery),不需要配置任何地面基础设施,而是把地面的停放车辆组成一个虚拟的停车覆盖网络,通过该停车覆盖网实现数据的传输.为此,首先,对于每一条道路,把路边和非路边停放车辆组成一个尽可能长的停车簇,并基于这些停车簇组织城市停车骨干网络.其次,设计基于停车覆盖网络的全新数据传输算法来实现车辆间的有效数据传输.基于真实城市地图和交通数据的模拟实验结果表明,与现有的几种数据传输算法相比,PBBD能够以较低的网络传输开销和较小的传输延迟获得较高的数据传输成功率.
文摘提出一种在机会网络中基于周期性间歇连通的数据传输策略PICD(periodic intermittently connected-based data delivery in opportunistic networks).通过有效利用节点间的周期间歇连通性改善数据传输性能.节点传输概率的计算则充分考虑了其与汇聚点间存在的间歇多跳路径,并将其与消息容忍的传输延迟相结合.首先,采用随机动态规划的方法建立与延迟相关的传输概率模型;然后,通过基于多跳的函数空间迭代法求出一个周期内的与延迟相关的传输概率分布矩阵;节点面向不同消息延迟的传输概率则基于分布矩阵计算获得,以此作为选择下一跳的依据.与延迟相关的概率转发机制提高了消息在容忍的延迟内被成功递交的可能.仿真实验结果表明,与现有的几种数据传输算法相比,在节点具有循环运动特征的环境下,PICD具有较高的数据传输成功率和较低的递交延迟.
文摘The low efficiency and high cost of fresh agricultural product terminal distribution directly restrict the operation of the entire supply network.To reduce costs and optimize the distribution network,we construct a mixed integer programmingmodel that comprehensively considers tominimize fixed,transportation,fresh-keeping,time,carbon emissions,and performance incentive costs.We analyzed the performance of traditional rider distribution and robot distribution modes in detail.In addition,the uncertainty of the actual market demand poses a huge threat to the stability of the terminal distribution network.In order to resist uncertain interference,we further extend the model to a robust counterpart form.The results of the simulation show that the instability of random parameters will lead to an increase in the cost.Compared with the traditional rider distribution mode,the robot distribution mode can save 12.7%on logistics costs,and the distribution efficiency is higher.Our research can provide support for the design of planning schemes for transportation enterprise managers.
基金Project supported by the National Natural Science Foundation of China(No.U21A20451)。
文摘Information-centric satellite networks play a crucial role in remote sensing applications,particularly in the transmission of remote sensing images.However,the occurrence of burst traffic poses significant challenges in meeting the increased bandwidth demands.Traditional content delivery networks are ill-equipped to handle such bursts due to their pre-deployed content.In this paper,we propose an optimal replication strategy for mitigating burst traffic in information-centric satellite networks,specifically focusing on the transmission of remote sensing images.Our strategy involves selecting the most optimal replication delivery satellite node when multiple users subscribe to the same remote sensing content within a short time,effectively reducing network transmission data and preventing throughput degradation caused by burst traffic expansion.We formulate the content delivery process as a multi-objective optimization problem and apply Markov decision processes to determine the optimal value for burst traffic reduction.To address these challenges,we leverage federated reinforcement learning techniques.Additionally,we use bloom filters with subdivision and data identification methods to enable rapid retrieval and encoding of remote sensing images.Through software-based simulations using a low Earth orbit satellite constellation,we validate the effectiveness of our proposed strategy,achieving a significant 17%reduction in the average delivery delay.This paper offers valuable insights into efficient content delivery in satellite networks,specifically targeting the transmission of remote sensing images,and presents a promising approach to mitigate burst traffic challenges in information-centric environments.
