In this paper, a novel reconfiguration technique is developed in the context of a fault-tolerant Networked Control System (NCS) in two train wagons. All sensors, controllers and actuators in both wagons are connected ...In this paper, a novel reconfiguration technique is developed in the context of a fault-tolerant Networked Control System (NCS) in two train wagons. All sensors, controllers and actuators in both wagons are connected on top of a single Gigabit Ethernet network. The network also carries wired and wireless entertainment loads. A Markov model is used to prove that this reconfiguration technique reduces the effect of a failure in the error detection and switching mechanisms on the reliability of the control function. All calculations are based on closed-form solutions and verified using the SHARPE software package.展开更多
In this paper, a new reliable hierarchical model is suggested for a two-wagon train Networked Control System. Each wagon has a Controller that carries the control load and an Entertainment server that handles the ente...In this paper, a new reliable hierarchical model is suggested for a two-wagon train Networked Control System. Each wagon has a Controller that carries the control load and an Entertainment server that handles the entertainment. A supervisory controller runs on top of the two controllers and the two entertainment servers. Contrary to a similar model in the literature, the Supervisory node replaces a Controller as soon as it fails (Active Supervisor). All system states are analyzed and simulated using OPNET. It is shown that, for all states, this architecture has zero control packets dropped and the end-to-end delay is below the maximum target delay. A comparison between this Active model and the other model in the literature is presented. It is found that the entertainment in this new architecture is kept available for the passengers in more of the system states when compared to the architecture previously presented in the literature.展开更多
随着列车通信技术的发展,列车控制网络的环境愈发复杂,车载设备对网络带宽和网络拓扑复杂度的要求愈发严格,列车互联网的物理层载体逐渐从串行通信总线网过渡到了以太网。为了保证以太网协议栈在列车互联网中的正常运行,结合列车互联网...随着列车通信技术的发展,列车控制网络的环境愈发复杂,车载设备对网络带宽和网络拓扑复杂度的要求愈发严格,列车互联网的物理层载体逐渐从串行通信总线网过渡到了以太网。为了保证以太网协议栈在列车互联网中的正常运行,结合列车互联网的独特需求,列车通信网络(train communication network,TCN)联盟提出了列车实时数据协议(train real-time data protocol,TRDP),现已成为车载设备数据传输中不可或缺的重要一环。然而,在引入以太网架构的同时,传统计算机网络面临的安全风险也被带入了列车通信网络中。架构在以太网之上的TRDP,缺乏有效的安全防护机制,面临着恶意攻击、数据泄露、拒绝服务等一系列风险。在TRDP的础上,分析了TRDP消息数据、过程数据两种协议模式的区别和安全需求,结合列车互联网的实际情况,选取合适的加密协议,改进了协议细节,设计了基于加密协议的安全防护机制。并在此基础上搭建了一个模型系统,系统展示了如何将这些关键的密码技术组合起来,构建一个安全的列车互联网信息系统,并证明了系统在保证协议安全性的情况下,能够满足列车互联网对TRDP的性能需求。展开更多
为了满足未来大容量、高速率、硬实时性的信息传输需求,将交换式以太网技术引入列车通信网络(TCN,train communication network)。针对不同优先级消息,根据其通信调度方式对传输过程建立了TCN的确定与随机Petri网(DSPN,determined and s...为了满足未来大容量、高速率、硬实时性的信息传输需求,将交换式以太网技术引入列车通信网络(TCN,train communication network)。针对不同优先级消息,根据其通信调度方式对传输过程建立了TCN的确定与随机Petri网(DSPN,determined and stochastic Petri nets)模型,比较了交换机不同调度算法对时延的影响,并分析了消息数目和产生周期,以及消息数目和吞吐量的关系。实验结果表明,采用优先级调度算法能在牺牲非实时数据时延的条件下降低实时数据的时延,验证了采用交换式以太网的TCN吞吐量远超过现有的TCN,并且能够为今后的设计和优化提供理论依据。展开更多
文摘In this paper, a novel reconfiguration technique is developed in the context of a fault-tolerant Networked Control System (NCS) in two train wagons. All sensors, controllers and actuators in both wagons are connected on top of a single Gigabit Ethernet network. The network also carries wired and wireless entertainment loads. A Markov model is used to prove that this reconfiguration technique reduces the effect of a failure in the error detection and switching mechanisms on the reliability of the control function. All calculations are based on closed-form solutions and verified using the SHARPE software package.
文摘In this paper, a new reliable hierarchical model is suggested for a two-wagon train Networked Control System. Each wagon has a Controller that carries the control load and an Entertainment server that handles the entertainment. A supervisory controller runs on top of the two controllers and the two entertainment servers. Contrary to a similar model in the literature, the Supervisory node replaces a Controller as soon as it fails (Active Supervisor). All system states are analyzed and simulated using OPNET. It is shown that, for all states, this architecture has zero control packets dropped and the end-to-end delay is below the maximum target delay. A comparison between this Active model and the other model in the literature is presented. It is found that the entertainment in this new architecture is kept available for the passengers in more of the system states when compared to the architecture previously presented in the literature.
文摘随着列车通信技术的发展,列车控制网络的环境愈发复杂,车载设备对网络带宽和网络拓扑复杂度的要求愈发严格,列车互联网的物理层载体逐渐从串行通信总线网过渡到了以太网。为了保证以太网协议栈在列车互联网中的正常运行,结合列车互联网的独特需求,列车通信网络(train communication network,TCN)联盟提出了列车实时数据协议(train real-time data protocol,TRDP),现已成为车载设备数据传输中不可或缺的重要一环。然而,在引入以太网架构的同时,传统计算机网络面临的安全风险也被带入了列车通信网络中。架构在以太网之上的TRDP,缺乏有效的安全防护机制,面临着恶意攻击、数据泄露、拒绝服务等一系列风险。在TRDP的础上,分析了TRDP消息数据、过程数据两种协议模式的区别和安全需求,结合列车互联网的实际情况,选取合适的加密协议,改进了协议细节,设计了基于加密协议的安全防护机制。并在此基础上搭建了一个模型系统,系统展示了如何将这些关键的密码技术组合起来,构建一个安全的列车互联网信息系统,并证明了系统在保证协议安全性的情况下,能够满足列车互联网对TRDP的性能需求。
文摘为了满足未来大容量、高速率、硬实时性的信息传输需求,将交换式以太网技术引入列车通信网络(TCN,train communication network)。针对不同优先级消息,根据其通信调度方式对传输过程建立了TCN的确定与随机Petri网(DSPN,determined and stochastic Petri nets)模型,比较了交换机不同调度算法对时延的影响,并分析了消息数目和产生周期,以及消息数目和吞吐量的关系。实验结果表明,采用优先级调度算法能在牺牲非实时数据时延的条件下降低实时数据的时延,验证了采用交换式以太网的TCN吞吐量远超过现有的TCN,并且能够为今后的设计和优化提供理论依据。
