随着智能电网的发展,电力系统对保护设备提出更高要求。文章设计一种基于Modbus传输控制协议(Modbus Transmission Control Protocol,Modbus-TCP)的智能断路器温度与电流双重保护系统,集成多参量融合传感技术与人工智能算法,有效提升断...随着智能电网的发展,电力系统对保护设备提出更高要求。文章设计一种基于Modbus传输控制协议(Modbus Transmission Control Protocol,Modbus-TCP)的智能断路器温度与电流双重保护系统,集成多参量融合传感技术与人工智能算法,有效提升断路器的保护性能和响应速度。该系统采用高精度温度与电流传感器,利用Modbus-TCP协议实现高效、可靠的通信。实验结果表明,该系统在过流保护、温度测量精度、通信时延等方面表现出色,满足现代配电自动化的技术需求。展开更多
An adaptive transmission control algorithm based on TCP （TCP-ATCA） is proposed to reduce the effects of long propagation delay and high link error rate of the satellite network on the performances. The flow control ...An adaptive transmission control algorithm based on TCP （TCP-ATCA） is proposed to reduce the effects of long propagation delay and high link error rate of the satellite network on the performances. The flow control and the error recovery are differentiated by combined dynamic random early detection-explicit congestion notification （DRED-ECN） algorithm, and, moreover, the pertaining congestion control methods are used in TCP-ATCA to improve the throughput. By introducing the entire recovery algorithm, the unnecessary congestion window decrease is reduced, and the throughput and fairness are improved. Simulation results show that, compared with TCP-Reno, TCP-ATCA provides a better throughput performance when the link capacity is higher （ ≥600 packet/s）, and roughly the same when it is lower. At the same time, TCP-ATCA also increases fairness and reduces transmission delay.展开更多
New wireless sensor network applications (e.g., military surveillance) require higher reliability than a simple best effort service could provide. Classical reliable transport protocols like Transmission Control Proto...New wireless sensor network applications (e.g., military surveillance) require higher reliability than a simple best effort service could provide. Classical reliable transport protocols like Transmission Control Protocol (TCP) are not well suited for wireless sensor networks due to both the characteristics of the network nodes (low computing power, strong energy constraints) and those of the main applications running on those nodes (low data rates). Recent researches present new transport protocols for wireless sensor networks providing various type of reliability and using new mechanisms for loss detection and recovery, and congestion control. This paper presents a survey on reliable transport protocol for WSNs.展开更多
Objective Analyzing the nonlinear dynamics of the TCP-RED congestion control system is of great importance. This study will help investigate the loss of stability in Internet and design a proper method for controlling...Objective Analyzing the nonlinear dynamics of the TCP-RED congestion control system is of great importance. This study will help investigate the loss of stability in Internet and design a proper method for controlling bifurcation and chaos in such system. Methods Based on bifurcation diagram, the effect of parameter on system performance is discussed. By using the state feedback and parameter variation strategy, a simple real time control method is proposed to modify the existing RED scheme. Results With our control method, the parametric sensitivity of RED mechanism is attenuated. Moreover, a sufficient condition on the robust stability of the system is also derived to adjust the parameters in TCP-RED system. Conclusion The proposed method has the advantages of simple implementation and unnecessary knowledge of the exact system.展开更多
As a result of the exponential growing rate of worldwide Internet usage, satellite systems are required to support broadband Internet applications. The transmission control protocol （TCP） which is widely used in the...As a result of the exponential growing rate of worldwide Internet usage, satellite systems are required to support broadband Internet applications. The transmission control protocol （TCP） which is widely used in the Internet, performs very well on wired networks. However, in the case of satellite channels, clue to the delay and transmission errors, TCP performance degrades significantly and bandwidth of satellite links can not be fully utilized. To improve the TCP performance, a new idea of placing a TCP spoofing proxy in the satellite is considered. A Novel Satellite Transport Protocol （NSTP） which takes advantage of the special properties of the satellite channel is also proposed. By using simulation, as compared with traditional TCPs, the on-board spoofing proxy integrated with the special transport protocol can significantly enhance throughput performance on the high BER satellite link, the time needed to transfer files and the bandwidth used in reverse path are sharply reduced.展开更多
Transmission control protocol (TCP) has undergone several transformations. Several proposals have been put forward to change the mechanisms of TCP congestion control to improve its performance. A line of research tend...Transmission control protocol (TCP) has undergone several transformations. Several proposals have been put forward to change the mechanisms of TCP congestion control to improve its performance. A line of research tends to reduce speed in the face of congestion thereby penalizing itself. In this group are the window based congestion control algorithms that use the size of congestion window to determine transmission speed. The two main algorithm of window based congestion control are the congestion avoidance and the slow start. The aim of this study is to survey the various modifications of window based congestion control. Much work has been done on congestion avoidance hence specific attention is placed on the slow start in order to motivate a new direction of research in network utility maximization. Mathematical modeling of the internet is discussed and proposals to improve TCP startup were reviewed. There are three lines of research on the improvement of slow start. A group uses the estimation of certain parameters to determine initial speed. The second group uses bandwidth estimation while the last group uses explicit request for network assistance to determine initial startup speed. The problems of each proposal are analyzed and a multiple startup for TCP is proposed. Multiple startups for TCP specify that startup speed is selectable from an n-arry set of algorithms. We then introduced the e-speed start which uses the prevailing network condition to determine a suitable starting speed.展开更多
The industrial Internet of Things(IIoT)is a new indus-trial idea that combines the latest information and communica-tion technologies with the industrial economy.In this paper,a cloud control structure is designed for...The industrial Internet of Things(IIoT)is a new indus-trial idea that combines the latest information and communica-tion technologies with the industrial economy.In this paper,a cloud control structure is designed for IIoT in cloud-edge envi-ronment with three modes of 5G.For 5G based IIoT,the time sensitive network(TSN)service is introduced in transmission network.A 5G logical TSN bridge is designed to transport TSN streams over 5G framework to achieve end-to-end configuration.For a transmission control protocol(TCP)model with nonlinear disturbance,time delay and uncertainties,a robust adaptive fuzzy sliding mode controller(AFSMC)is given with control rule parameters.IIoT workflows are made up of a series of subtasks that are linked by the dependencies between sensor datasets and task flows.IIoT workflow scheduling is a non-deterministic polynomial(NP)-hard problem in cloud-edge environment.An adaptive and non-local-convergent particle swarm optimization(ANCPSO)is designed with nonlinear inertia weight to avoid falling into local optimum,which can reduce the makespan and cost dramatically.Simulation and experiments demonstrate that ANCPSO has better performances than other classical algo-rithms.展开更多
分布式电源(distributed resources,DR)中智能边缘设备数据传输的安全问题为电力系统带来了安全隐患。Modbus TCP(transmission control protocol)协议作为边缘设备采用的通信手段之一,其协议安全性的不足使得系统易遭到网络空间的攻击...分布式电源(distributed resources,DR)中智能边缘设备数据传输的安全问题为电力系统带来了安全隐患。Modbus TCP(transmission control protocol)协议作为边缘设备采用的通信手段之一,其协议安全性的不足使得系统易遭到网络空间的攻击。为保障电力设备数据传输安全,对现有安全手段进行整理,分析现有安全手段在DR应用场景下的不足,提出一种非侵入式Modbus TCP协议安全增强方法。该方法采用云边协同的架构,利用电力控制中心云平台管理访问控制原则,将实际访问控制决策模块部署在边缘设备,并通过细粒度的访问控制组合限制恶意行为。依据Modbus协议参考指南,搭建DR应用场景进行渗透测试,验证该方法能有效防御重放攻击和中间人攻击,可将安全开销控制在百微秒以内,显著优于其他安全手段,满足DR对实时性的需求。展开更多
Transmission Control Protocol (TCP) optimization in Mobile Ad hoc NETworks (MANETs) is a challenging issue because of some unique characteristics of MANETs. In this paper,a new end-to-end mechanism based on multiple m...Transmission Control Protocol (TCP) optimization in Mobile Ad hoc NETworks (MANETs) is a challenging issue because of some unique characteristics of MANETs. In this paper,a new end-to-end mechanism based on multiple metrics measurement is proposed to improve TCP performance in MANETs. Multi-metric Measurement based Enhancement of TCP (MME-TCP) designs the metrics and the identification algorithm according to the characteristics of MANETs and the experiment results. Furthermore,these metrics are measured at the sender node to reduce the overhead of control information over networks. Simulation results show that MME-TCP mechanism achieves a significant performance improvement over standard TCP in MANETs.展开更多
为提高移动自组网的网络性能和推进Semi-TCP方法的实际应用,提出基于路由协议的Semi-TCP网络层逐跳拥塞控制实现方法。通过在网络层的路由协议中加入拥塞信息广播机制,控制节点对数据包的发送频率,保持链路高速传输数据的同时,降低拥塞...为提高移动自组网的网络性能和推进Semi-TCP方法的实际应用,提出基于路由协议的Semi-TCP网络层逐跳拥塞控制实现方法。通过在网络层的路由协议中加入拥塞信息广播机制,控制节点对数据包的发送频率,保持链路高速传输数据的同时,降低拥塞程度。在EXata仿真平台进行了验证,在设计的动态拓扑实验中,文中方法的吞吐量相比TCP New Reno提高了169.57%,在引入多TCP应用竞争链路后比原Semi-TCP方法提高19.52%,证明了文中方法的有效性。展开更多
传统TCP(transmission control protocol)本是为有线网络设计,它假设包丢失全是由网络拥塞引起,这个假设不能适应于MANET (mobile ad hoc network),因为MANET 中除了拥塞丢包以外,还存在由于较高比特误码率、路由故障等因素引起的丢包现...传统TCP(transmission control protocol)本是为有线网络设计,它假设包丢失全是由网络拥塞引起,这个假设不能适应于MANET (mobile ad hoc network),因为MANET 中除了拥塞丢包以外,还存在由于较高比特误码率、路由故障等因素引起的丢包现象.当出现非拥塞因素丢包时,传统 TCP 将错误地触发拥塞控制,从而引起TCP 性能低下.任何改进机制都可以分为发现问题和解决问题两个阶段.首先概括了 MANET 中影响 TCP 性能的若干问题;然后针对发现问题和解决问题两个阶段,详细地对每一阶段中存在的各种可行方法进行了分类、分析和比较;最后指出了 MANET 中 TCP 性能优化的研究方向.展开更多
文摘随着智能电网的发展,电力系统对保护设备提出更高要求。文章设计一种基于Modbus传输控制协议(Modbus Transmission Control Protocol,Modbus-TCP)的智能断路器温度与电流双重保护系统,集成多参量融合传感技术与人工智能算法,有效提升断路器的保护性能和响应速度。该系统采用高精度温度与电流传感器,利用Modbus-TCP协议实现高效、可靠的通信。实验结果表明,该系统在过流保护、温度测量精度、通信时延等方面表现出色,满足现代配电自动化的技术需求。
基金National Natural Science Foundation of China (60502017, 60532030, 60625102)The Blue-Sky New Star Grant of Beijing University of Aeronautics and Astronautics (2004)
文摘An adaptive transmission control algorithm based on TCP （TCP-ATCA） is proposed to reduce the effects of long propagation delay and high link error rate of the satellite network on the performances. The flow control and the error recovery are differentiated by combined dynamic random early detection-explicit congestion notification （DRED-ECN） algorithm, and, moreover, the pertaining congestion control methods are used in TCP-ATCA to improve the throughput. By introducing the entire recovery algorithm, the unnecessary congestion window decrease is reduced, and the throughput and fairness are improved. Simulation results show that, compared with TCP-Reno, TCP-ATCA provides a better throughput performance when the link capacity is higher （ ≥600 packet/s）, and roughly the same when it is lower. At the same time, TCP-ATCA also increases fairness and reduces transmission delay.
文摘New wireless sensor network applications (e.g., military surveillance) require higher reliability than a simple best effort service could provide. Classical reliable transport protocols like Transmission Control Protocol (TCP) are not well suited for wireless sensor networks due to both the characteristics of the network nodes (low computing power, strong energy constraints) and those of the main applications running on those nodes (low data rates). Recent researches present new transport protocols for wireless sensor networks providing various type of reliability and using new mechanisms for loss detection and recovery, and congestion control. This paper presents a survey on reliable transport protocol for WSNs.
文摘Objective Analyzing the nonlinear dynamics of the TCP-RED congestion control system is of great importance. This study will help investigate the loss of stability in Internet and design a proper method for controlling bifurcation and chaos in such system. Methods Based on bifurcation diagram, the effect of parameter on system performance is discussed. By using the state feedback and parameter variation strategy, a simple real time control method is proposed to modify the existing RED scheme. Results With our control method, the parametric sensitivity of RED mechanism is attenuated. Moreover, a sufficient condition on the robust stability of the system is also derived to adjust the parameters in TCP-RED system. Conclusion The proposed method has the advantages of simple implementation and unnecessary knowledge of the exact system.
文摘As a result of the exponential growing rate of worldwide Internet usage, satellite systems are required to support broadband Internet applications. The transmission control protocol （TCP） which is widely used in the Internet, performs very well on wired networks. However, in the case of satellite channels, clue to the delay and transmission errors, TCP performance degrades significantly and bandwidth of satellite links can not be fully utilized. To improve the TCP performance, a new idea of placing a TCP spoofing proxy in the satellite is considered. A Novel Satellite Transport Protocol （NSTP） which takes advantage of the special properties of the satellite channel is also proposed. By using simulation, as compared with traditional TCPs, the on-board spoofing proxy integrated with the special transport protocol can significantly enhance throughput performance on the high BER satellite link, the time needed to transfer files and the bandwidth used in reverse path are sharply reduced.
文摘Transmission control protocol (TCP) has undergone several transformations. Several proposals have been put forward to change the mechanisms of TCP congestion control to improve its performance. A line of research tends to reduce speed in the face of congestion thereby penalizing itself. In this group are the window based congestion control algorithms that use the size of congestion window to determine transmission speed. The two main algorithm of window based congestion control are the congestion avoidance and the slow start. The aim of this study is to survey the various modifications of window based congestion control. Much work has been done on congestion avoidance hence specific attention is placed on the slow start in order to motivate a new direction of research in network utility maximization. Mathematical modeling of the internet is discussed and proposals to improve TCP startup were reviewed. There are three lines of research on the improvement of slow start. A group uses the estimation of certain parameters to determine initial speed. The second group uses bandwidth estimation while the last group uses explicit request for network assistance to determine initial startup speed. The problems of each proposal are analyzed and a multiple startup for TCP is proposed. Multiple startups for TCP specify that startup speed is selectable from an n-arry set of algorithms. We then introduced the e-speed start which uses the prevailing network condition to determine a suitable starting speed.
文摘The industrial Internet of Things(IIoT)is a new indus-trial idea that combines the latest information and communica-tion technologies with the industrial economy.In this paper,a cloud control structure is designed for IIoT in cloud-edge envi-ronment with three modes of 5G.For 5G based IIoT,the time sensitive network(TSN)service is introduced in transmission network.A 5G logical TSN bridge is designed to transport TSN streams over 5G framework to achieve end-to-end configuration.For a transmission control protocol(TCP)model with nonlinear disturbance,time delay and uncertainties,a robust adaptive fuzzy sliding mode controller(AFSMC)is given with control rule parameters.IIoT workflows are made up of a series of subtasks that are linked by the dependencies between sensor datasets and task flows.IIoT workflow scheduling is a non-deterministic polynomial(NP)-hard problem in cloud-edge environment.An adaptive and non-local-convergent particle swarm optimization(ANCPSO)is designed with nonlinear inertia weight to avoid falling into local optimum,which can reduce the makespan and cost dramatically.Simulation and experiments demonstrate that ANCPSO has better performances than other classical algo-rithms.
基金Supported by the National Natural Science Foundation of China (No.60496314)the Chinese 863 National High Technology Program (No.2002AA783043).
文摘Transmission Control Protocol (TCP) optimization in Mobile Ad hoc NETworks (MANETs) is a challenging issue because of some unique characteristics of MANETs. In this paper,a new end-to-end mechanism based on multiple metrics measurement is proposed to improve TCP performance in MANETs. Multi-metric Measurement based Enhancement of TCP (MME-TCP) designs the metrics and the identification algorithm according to the characteristics of MANETs and the experiment results. Furthermore,these metrics are measured at the sender node to reduce the overhead of control information over networks. Simulation results show that MME-TCP mechanism achieves a significant performance improvement over standard TCP in MANETs.
文摘为提高移动自组网的网络性能和推进Semi-TCP方法的实际应用,提出基于路由协议的Semi-TCP网络层逐跳拥塞控制实现方法。通过在网络层的路由协议中加入拥塞信息广播机制,控制节点对数据包的发送频率,保持链路高速传输数据的同时,降低拥塞程度。在EXata仿真平台进行了验证,在设计的动态拓扑实验中,文中方法的吞吐量相比TCP New Reno提高了169.57%,在引入多TCP应用竞争链路后比原Semi-TCP方法提高19.52%,证明了文中方法的有效性。
