基于弹性理论的城市轨道交通车地通信系统可信性和安全性综合评估理论研究

To fully evaluate the depandability and the security of the train-ground communications of urban rail transit systems, the modelling of system disturbance based on the train control mechanism and safety design rules is always regarded as the core component. Considering the disadvantages of the classic method just aiming at the communication performance, the dependability and security of train-ground communications cannot be completely evaluated. The project will begin with the attack graph which can design the dependability and security boundaries and describe the propagation mechanisms of system disturbance. With the application of cognitive control, the coupling characteristics of communication systems and control systems can be obtained, where the relationship between the system disturbance and the variance of train control performance can be built. Based on the resilience, dependability and security can be integrated. As a result, we can evaluate the impacts of system disturbance from the view of the whole urban rail transit system where the number of dimensions of evaluation indexes can be reduced, and some practical suggestions can be provided for the design and optimization of the train-ground communications of urban rail transit systems.

为了充分研究城市轨道交通车地通信系统的可信性和安全性，基于列车控制机制和安全设计准则对以干扰和恶意攻击为代表的系统扰动建模和分析是基础。考虑到现有研究工作主要从通信网络的角度来描述的系统扰动，从而无法从整体评估车地通信系统的可信性和安全性。本项目将从攻击图出发，以系统固有机制为约束函数描述系统扰动的传播机理和系统的可信及安全边界。利用认知控制实现通信系统和控制系统耦合特性的提取，从而能够将系统扰动的影响引入到列车控制性能的变化中。利用弹性理论将可信性和安全性进行整合，从而对整个评估周期的列车运行控制系统性能进行整体描述，有效地降低了系统评估指标的维度，为城市轨道交通车地通信系统的设计和优化提供理论依据。

为了全面量化城市轨道交通车地通信系统的可信性和安全性，本课题从列控系统结构和执行机制出发，以车地无线通信链路为切入点，基于攻击树/攻击图对以网络攻击为代表的系统扰动特征进行了描述，并结合信息流分析了系统扰动的传播路径，探明了系统扰动的演化机理，进而量化分析包括车地通信系统在内的列控系统性能的变化，实现了功能安全和信息安全的融合。进一步，结合列车动力学控制模型，探明列车控制和车地通信系统之间的耦合关系，进而基于认知控制实现系统扰动下的列车控制策略和车地通信参数之间的联合优化，保障了系统的鲁棒性和抗扰性。最后，基于二维结构熵实现了物理域列控性能指标和信息域网络性能指标的融合，以此为基础构建弹性指标体系，实现对列控系统可信性和安全性的量化分析，从列控系统的安全防护水平和可信度的提升提供了理论和技术指导。