With the rapid development of the Internet,people pay more and more attention to the protection of privacy.The second-generation onion routing system Tor is the most commonly used among anonymous communication systems...With the rapid development of the Internet,people pay more and more attention to the protection of privacy.The second-generation onion routing system Tor is the most commonly used among anonymous communication systems,which can be used to protect user privacy effectively.In recent years,Tor’s congestion problem has become the focus of attention,and it can affect Tor’s performance even user experience.Firstly,we investigate the causes of Tor network congestion and summarize some link scheduling algorithms proposed in recent years.Then we propose the link scheduling algorithm SWRR based on WRR(Weighted Round Robin).In this process,we design multiple weight functions and compare the performance of these weight functions under different congestion conditions,and the appropriate weight function is selected to be used in our algorithms based on the experiment results.Finally,we also compare the performance of SWRR with other link scheduling algorithms under different congestion conditions by experiments,and verify the effectiveness of the algorithm SWRR.展开更多
This paper introduces a Kalman-type recursive state estimator for a class of discrete-time stochastic linear singular systems where the measurements are carried part by part periodically following a scheduling algorit...This paper introduces a Kalman-type recursive state estimator for a class of discrete-time stochastic linear singular systems where the measurements are carried part by part periodically following a scheduling algorithm.We consider that the system is in a network with limited allotted bandwidth,which refers to a situation where the total available bandwidth for data transmission through the network is limited.This limitation can occur for various reasons,such as network congestion,resource allocation policies,or bandwidth limitations imposed by network administrators.In such networks,the entire measurement vector cannot be transmitted to the estimator instantly.Thus,managing a network with a limited allotted bandwidth requires careful planning,monitoring,and implementing some scheduling strategies to optimize the use of measured data while estimating the system states.We show that a scheduling method,namely,round-robin protocol,is suitable for singular systems to deal with such a scenario.The upper bound of the prior error covariance is studied via a periodic Riccati equation(PRE).To retain the boundedness of prior error covariance,the stability of the PRE is examined by the observability properties of the round-robin-induced system.Finally,a simulation example is presented to show the effectiveness of the designed filtering scheme.展开更多
With the support of Vehicle-to-Everything(V2X)technology and computing power networks,the existing intersection traffic order is expected to benefit from efficiency improvements and energy savings by new schemes such ...With the support of Vehicle-to-Everything(V2X)technology and computing power networks,the existing intersection traffic order is expected to benefit from efficiency improvements and energy savings by new schemes such as de-signalization.How to effectively manage autonomous vehicles for traffic control with high throughput at unsignalized intersections while ensuring safety has been a research hotspot.This paper proposes a collision-free autonomous vehicle scheduling framework based on edge-cloud computing power networks for unsignalized intersections where the lanes entering the intersections are undirectional,and designs an efficient communication system and protocol.First,by analyzing the collision point occupation time,this paper formulates an absolute value programming problem.Second,this problem is solved with low complexity by the Edge Intelligence Optimal Entry Time(EI-OET)algorithm based on edge-cloud computing power support.Then,the communication system and protocol are designed for the proposed scheduling scheme to realize efficient and low-latency vehicular communications.Finally,simulation experiments compare the proposed scheduling framework with directional and traditional traffic light scheduling mechanisms,and the experimental results demonstrate its high efficiency,low latency,and low complexity.展开更多
Recently,a round-robin differential phase-shift（RRDPS） protocol was proposed[Nature 509,475（2014）],in which the amount of leakage is bounded without monitoring the signal disturbance.Introducing states of the phas...Recently,a round-robin differential phase-shift（RRDPS） protocol was proposed[Nature 509,475（2014）],in which the amount of leakage is bounded without monitoring the signal disturbance.Introducing states of the phase-encoded Bennett-Brassard 1984 protocol（PE-BB84） to the RRDPS,this paper presents another quantum key distribution protocol called round-robin differential quadrature phase-shift（RRDQPS） quantum key distribution.Regarding a train of many pulses as a single packet,the sender modulates the phase of each pulse by one of {0,π/2,π,3π/2},then the receiver measures each packet with a Mach-Zehnder interferometer having a phase basis of 0 or π/2.The RRDQPS protocol can be implemented with essential similar hardware to the PE-BB84,so it has great compatibility with the current quantum system.Here we analyze the security of the RRDQPS protocol against the intercept-resend attack and the beam-splitting attack.Results show that the proposed protocol inherits the advantages arising from the simplicity of the RRDPS protocol and is more robust against these attacks than the original protocol.展开更多
在移动直播场景中,多路径传输控制协议(Multi-Path Transmission Control Protocol,MPTCP)采用的默认调度策略是最小往返时延(Round-Trip Time,RTT)调度(MinRTT),仅依据最小RTT来选择传输路径。这一特性使得安全可靠的专网路径因时延略...在移动直播场景中,多路径传输控制协议(Multi-Path Transmission Control Protocol,MPTCP)采用的默认调度策略是最小往返时延(Round-Trip Time,RTT)调度(MinRTT),仅依据最小RTT来选择传输路径。这一特性使得安全可靠的专网路径因时延略高无法充分利用,且专网与公网切换不及时,容易引发画面卡顿问题。对此,提出一种基于MinRTT的专网优先无感切换调度策略。该策略通过优先检测专网的可用性,并利用卡尔曼滤波器对专网的RTT进行预测,从而实现专网优先传输数据和无感切换的效果。实验结果表明,与MinRTT相比,所提策略在移动直播场景中显著提升了传输稳定性。展开更多
This paper addresses the ultimate boundedness control problem for a class of networked nonlinear systems with the round-robin(RR)protocol and uniform quantisation.The communication between sensor nodes and the control...This paper addresses the ultimate boundedness control problem for a class of networked nonlinear systems with the round-robin(RR)protocol and uniform quantisation.The communication between sensor nodes and the controller is implemented via a constrained communication channel.The quantised output of the system is transmitted to the remote controller through a communication channel subject to a transmission delay.For the purpose of alleviating possible data collision,the well-known RR communication protocol is deployed to schedule the data transmissions.On the other hand,the uniform quantisation effects of the network are characterised by a round function(i.e.the nearest integer function).The purpose of the addressed problem is to design an observer-based controller for the networked nonlinear systems such that,in the presence of RR protocol and uniform quantisation effects,the closed-loop system is ultimately bounded.The controller is designed based on mean square stability analysis and Lyapunov-like method.A set of sufficient conditions for the ultimate boundedness of the closed-loop system are established and,on the basis of which,the desired controller gains are obtained by solving a set of linear matrix inequalities.The effectiveness of the proposed method is verified by numerical examples.展开更多
The practical engineering of satellite tracking telemetry and command(TT&C)is often disturbed by unpredictable external factors,including the temporary rise in a significant quantity of satellite TT&C tasks,te...The practical engineering of satellite tracking telemetry and command(TT&C)is often disturbed by unpredictable external factors,including the temporary rise in a significant quantity of satellite TT&C tasks,temporary failures and failures of some TT&C resources,and so on.To improve the adaptability and robustness of satellite TT&C systems when faced with uncertain dynamic disturbances,a hierarchical disturbance propagation mechanism and an improved contract network dynamic scheduling method for satellite TT&C resources were designed to address the dynamic scheduling problem of satellite TT&C resources.Firstly,the characteristics of the dynamic scheduling problem of satellite TT&C resources are analyzed,and a mathematical model is established with the weighted optimization objectives of maximizing the revenue from task completion and minimizing the degree of plan disturbance.Then,a bottom-up distributed dynamic collaborative scheduling framework for satellite TT&C resources is proposed,which includes a task layer,a resource layer,a central internal collaboration layer,and a central external collaboration layer.Dynamic disturbances are propagated layer by layer from the task layer to the central external collaboration layer in a bottom-up manner,using efficient heuristic strategies in the task layer and the resource layer,respectively.We use improved contract network algorithms in the center internal collaboration layer and the center external collaboration layer,the original scheduling plan is quickly adjusted to minimize the impact of disturbances while effectively completing dynamic task requirements.Finally,a large number of simulation experiments were carried out and compared with various comparative algorithms.The results show that the proposed algorithm can effectively improve the solution effect of satellite TT&C resource dynamic scheduling problems,and has good application prospects.展开更多
火电厂辅控系统连接主控平台与各类现场设备,其效率与稳定性直接影响660 MW等级超临界机组的调度能力与运行质量。文章设计基于Modbus传输控制协议(Modbus Transmission Control Protocol,Modbus-TCP)的660MW火电厂辅控系统,采用网络拓...火电厂辅控系统连接主控平台与各类现场设备,其效率与稳定性直接影响660 MW等级超临界机组的调度能力与运行质量。文章设计基于Modbus传输控制协议(Modbus Transmission Control Protocol,Modbus-TCP)的660MW火电厂辅控系统,采用网络拓扑冗余机制、异构协议网关模块、图神经网络调度优化模型与多级安全防护策略。借助实际工程测试完成对通信延迟、指令丢失、协议切换效率与系统吞吐等指标的量化评估,为660 MW等级以上火电系统的通信平台优化提供模型支撑与参考范式。展开更多
为解决传统程控交换系统灵活性不足与软件定义网络(Software Defined Network,SDN)兼容性欠缺的双重问题,开展SDN与程控交换系统融合架构中的协议转换机制研究。剖析两类系统的协议差异,明确协议转换在语法、语义、时序3个维度的核心目...为解决传统程控交换系统灵活性不足与软件定义网络(Software Defined Network,SDN)兼容性欠缺的双重问题,开展SDN与程控交换系统融合架构中的协议转换机制研究。剖析两类系统的协议差异,明确协议转换在语法、语义、时序3个维度的核心目标,构建“控制层-转换层-接入层”3级融合架构。其中,转换层作为核心模块,采用“中间格式映射+状态机调度”的技术方案,通过协议字段映射表与转换优先级调度策略优化性能。实验结果表明,所提机制在1000并发呼叫请求下,协议转换延迟小于等于5 ms,转换成功率达99.8%,相比传统网关方案性能明显提升,能够满足融合架构对实时性与可靠性的需求,为电信网络向软件化转型提供技术支撑。展开更多
基金This work is supported by the National Natural Science Foundation of China(Grant No.61170273,No.U1536111)and the China Scholarship Council(No.[2013]3050).In addition,we express our sincere gratitude to Lingling Gong,Meng Luo,Zhimin Lin,Peiyuan Li and the anonymous reviewers for their valuable comments and suggestions.
文摘With the rapid development of the Internet,people pay more and more attention to the protection of privacy.The second-generation onion routing system Tor is the most commonly used among anonymous communication systems,which can be used to protect user privacy effectively.In recent years,Tor’s congestion problem has become the focus of attention,and it can affect Tor’s performance even user experience.Firstly,we investigate the causes of Tor network congestion and summarize some link scheduling algorithms proposed in recent years.Then we propose the link scheduling algorithm SWRR based on WRR(Weighted Round Robin).In this process,we design multiple weight functions and compare the performance of these weight functions under different congestion conditions,and the appropriate weight function is selected to be used in our algorithms based on the experiment results.Finally,we also compare the performance of SWRR with other link scheduling algorithms under different congestion conditions by experiments,and verify the effectiveness of the algorithm SWRR.
基金supported by the Science and Engineering Research Board,New Delhi(No.MTR/2019/000494).
文摘This paper introduces a Kalman-type recursive state estimator for a class of discrete-time stochastic linear singular systems where the measurements are carried part by part periodically following a scheduling algorithm.We consider that the system is in a network with limited allotted bandwidth,which refers to a situation where the total available bandwidth for data transmission through the network is limited.This limitation can occur for various reasons,such as network congestion,resource allocation policies,or bandwidth limitations imposed by network administrators.In such networks,the entire measurement vector cannot be transmitted to the estimator instantly.Thus,managing a network with a limited allotted bandwidth requires careful planning,monitoring,and implementing some scheduling strategies to optimize the use of measured data while estimating the system states.We show that a scheduling method,namely,round-robin protocol,is suitable for singular systems to deal with such a scenario.The upper bound of the prior error covariance is studied via a periodic Riccati equation(PRE).To retain the boundedness of prior error covariance,the stability of the PRE is examined by the observability properties of the round-robin-induced system.Finally,a simulation example is presented to show the effectiveness of the designed filtering scheme.
基金supported by the Natural Science Fund for Distinguished Young Scholars of Jiangsu Province under Grant BK20220067。
文摘With the support of Vehicle-to-Everything(V2X)technology and computing power networks,the existing intersection traffic order is expected to benefit from efficiency improvements and energy savings by new schemes such as de-signalization.How to effectively manage autonomous vehicles for traffic control with high throughput at unsignalized intersections while ensuring safety has been a research hotspot.This paper proposes a collision-free autonomous vehicle scheduling framework based on edge-cloud computing power networks for unsignalized intersections where the lanes entering the intersections are undirectional,and designs an efficient communication system and protocol.First,by analyzing the collision point occupation time,this paper formulates an absolute value programming problem.Second,this problem is solved with low complexity by the Edge Intelligence Optimal Entry Time(EI-OET)algorithm based on edge-cloud computing power support.Then,the communication system and protocol are designed for the proposed scheduling scheme to realize efficient and low-latency vehicular communications.Finally,simulation experiments compare the proposed scheduling framework with directional and traditional traffic light scheduling mechanisms,and the experimental results demonstrate its high efficiency,low latency,and low complexity.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61505261 and 11304397)the National Basic Research Program of China(Grant No.2013CB338002)
文摘Recently,a round-robin differential phase-shift（RRDPS） protocol was proposed[Nature 509,475（2014）],in which the amount of leakage is bounded without monitoring the signal disturbance.Introducing states of the phase-encoded Bennett-Brassard 1984 protocol（PE-BB84） to the RRDPS,this paper presents another quantum key distribution protocol called round-robin differential quadrature phase-shift（RRDQPS） quantum key distribution.Regarding a train of many pulses as a single packet,the sender modulates the phase of each pulse by one of {0,π/2,π,3π/2},then the receiver measures each packet with a Mach-Zehnder interferometer having a phase basis of 0 or π/2.The RRDQPS protocol can be implemented with essential similar hardware to the PE-BB84,so it has great compatibility with the current quantum system.Here we analyze the security of the RRDQPS protocol against the intercept-resend attack and the beam-splitting attack.Results show that the proposed protocol inherits the advantages arising from the simplicity of the RRDPS protocol and is more robust against these attacks than the original protocol.
文摘在移动直播场景中,多路径传输控制协议(Multi-Path Transmission Control Protocol,MPTCP)采用的默认调度策略是最小往返时延(Round-Trip Time,RTT)调度(MinRTT),仅依据最小RTT来选择传输路径。这一特性使得安全可靠的专网路径因时延略高无法充分利用,且专网与公网切换不及时,容易引发画面卡顿问题。对此,提出一种基于MinRTT的专网优先无感切换调度策略。该策略通过优先检测专网的可用性,并利用卡尔曼滤波器对专网的RTT进行预测,从而实现专网优先传输数据和无感切换的效果。实验结果表明,与MinRTT相比,所提策略在移动直播场景中显著提升了传输稳定性。
基金supported in part by the National Natural Science Foundation of China under Grants 62173079 and U1808205the Science and Technology Program of Gansu Province under Grant 21ZD4GA028.
文摘This paper addresses the ultimate boundedness control problem for a class of networked nonlinear systems with the round-robin(RR)protocol and uniform quantisation.The communication between sensor nodes and the controller is implemented via a constrained communication channel.The quantised output of the system is transmitted to the remote controller through a communication channel subject to a transmission delay.For the purpose of alleviating possible data collision,the well-known RR communication protocol is deployed to schedule the data transmissions.On the other hand,the uniform quantisation effects of the network are characterised by a round function(i.e.the nearest integer function).The purpose of the addressed problem is to design an observer-based controller for the networked nonlinear systems such that,in the presence of RR protocol and uniform quantisation effects,the closed-loop system is ultimately bounded.The controller is designed based on mean square stability analysis and Lyapunov-like method.A set of sufficient conditions for the ultimate boundedness of the closed-loop system are established and,on the basis of which,the desired controller gains are obtained by solving a set of linear matrix inequalities.The effectiveness of the proposed method is verified by numerical examples.
基金This work was supported in part by the National Natural Science Foundation of China(No.62373380).
文摘The practical engineering of satellite tracking telemetry and command(TT&C)is often disturbed by unpredictable external factors,including the temporary rise in a significant quantity of satellite TT&C tasks,temporary failures and failures of some TT&C resources,and so on.To improve the adaptability and robustness of satellite TT&C systems when faced with uncertain dynamic disturbances,a hierarchical disturbance propagation mechanism and an improved contract network dynamic scheduling method for satellite TT&C resources were designed to address the dynamic scheduling problem of satellite TT&C resources.Firstly,the characteristics of the dynamic scheduling problem of satellite TT&C resources are analyzed,and a mathematical model is established with the weighted optimization objectives of maximizing the revenue from task completion and minimizing the degree of plan disturbance.Then,a bottom-up distributed dynamic collaborative scheduling framework for satellite TT&C resources is proposed,which includes a task layer,a resource layer,a central internal collaboration layer,and a central external collaboration layer.Dynamic disturbances are propagated layer by layer from the task layer to the central external collaboration layer in a bottom-up manner,using efficient heuristic strategies in the task layer and the resource layer,respectively.We use improved contract network algorithms in the center internal collaboration layer and the center external collaboration layer,the original scheduling plan is quickly adjusted to minimize the impact of disturbances while effectively completing dynamic task requirements.Finally,a large number of simulation experiments were carried out and compared with various comparative algorithms.The results show that the proposed algorithm can effectively improve the solution effect of satellite TT&C resource dynamic scheduling problems,and has good application prospects.
文摘为解决传统程控交换系统灵活性不足与软件定义网络(Software Defined Network,SDN)兼容性欠缺的双重问题,开展SDN与程控交换系统融合架构中的协议转换机制研究。剖析两类系统的协议差异,明确协议转换在语法、语义、时序3个维度的核心目标,构建“控制层-转换层-接入层”3级融合架构。其中,转换层作为核心模块,采用“中间格式映射+状态机调度”的技术方案,通过协议字段映射表与转换优先级调度策略优化性能。实验结果表明,所提机制在1000并发呼叫请求下,协议转换延迟小于等于5 ms,转换成功率达99.8%,相比传统网关方案性能明显提升,能够满足融合架构对实时性与可靠性的需求,为电信网络向软件化转型提供技术支撑。
