Timing jitter is one of the main factors that influence on the accuracy of time domain precision measurement. Timing jitter compensation is one of the problems people concern. Because of the flaws of median method, PD...Timing jitter is one of the main factors that influence on the accuracy of time domain precision measurement. Timing jitter compensation is one of the problems people concern. Because of the flaws of median method, PDF deconvolution method and synthetic method, we put forward a new method for timing jitter compensation, which is called advanced median method. The theory of the advanced median method based on probability and statistics is analyzed, and the process of the advanced median method is summarized in this paper. Simulation and experiment show that compared with other methods, the new method could compensate timing jitter effectively.展开更多
为降低现有列车网络控制系统(train control and management system,TCMS)端到端时延、抖动不确定性对列车控制功能时间确定性的影响,提高列车控制功能迭代效率,基于下一代列车网络控制系统(next generation TCMS,NG-TCMS),提出通信与...为降低现有列车网络控制系统(train control and management system,TCMS)端到端时延、抖动不确定性对列车控制功能时间确定性的影响,提高列车控制功能迭代效率,基于下一代列车网络控制系统(next generation TCMS,NG-TCMS),提出通信与计算资源联合调度模型,将端到端确定性从网络层延伸至列车控制功能。首先,结合NG-TCMS中时间敏感网络提供的全局统一时间基准,将列车控制功能拆分为具有依赖关系的状态采集、逻辑计算、数据转发、命令执行任务,并通过有向无环图进行形式化。以最小化执行时间为调度目标,分别通过一阶逻辑约束转化为可满足性模理论(satisfiability modulo theories,SMT)问题进行最优求解,以及抽象为整数线性规划(integer linear programming,ILP)问题进行最优求解。同时,提出基于任务松弛度和抖动继承值的快速求解方法,将一次性求解所有任务的大规模调度转化为迭代求解单任务或双任务的小规模调度,以解决控制功能数量陡增导致调度问题复杂度激增,SMT方法和ILP方法难以快速求解的问题。最后,参考CR450动车组列车控制功能设计算例,以30 min为求解时间上限,分析SMT方法、ILP方法、快速求解方法在求解时间与所得调度方案资源利用率方面的性能差异。结果表明,快速求解方法能在20 min内完成1000个含零抖动和抖动约束的控制功能调度,高效调度系统资源,满足NG-TCMS快速迭代需求。研究结果可为基于NG-TCMS构建具有端到端时间确定性的列车网络控制功能及任务调度方法提供参考。展开更多
基金National Natural Science Foundation of China (50605065)
文摘Timing jitter is one of the main factors that influence on the accuracy of time domain precision measurement. Timing jitter compensation is one of the problems people concern. Because of the flaws of median method, PDF deconvolution method and synthetic method, we put forward a new method for timing jitter compensation, which is called advanced median method. The theory of the advanced median method based on probability and statistics is analyzed, and the process of the advanced median method is summarized in this paper. Simulation and experiment show that compared with other methods, the new method could compensate timing jitter effectively.
文摘为降低现有列车网络控制系统(train control and management system,TCMS)端到端时延、抖动不确定性对列车控制功能时间确定性的影响,提高列车控制功能迭代效率,基于下一代列车网络控制系统(next generation TCMS,NG-TCMS),提出通信与计算资源联合调度模型,将端到端确定性从网络层延伸至列车控制功能。首先,结合NG-TCMS中时间敏感网络提供的全局统一时间基准,将列车控制功能拆分为具有依赖关系的状态采集、逻辑计算、数据转发、命令执行任务,并通过有向无环图进行形式化。以最小化执行时间为调度目标,分别通过一阶逻辑约束转化为可满足性模理论(satisfiability modulo theories,SMT)问题进行最优求解,以及抽象为整数线性规划(integer linear programming,ILP)问题进行最优求解。同时,提出基于任务松弛度和抖动继承值的快速求解方法,将一次性求解所有任务的大规模调度转化为迭代求解单任务或双任务的小规模调度,以解决控制功能数量陡增导致调度问题复杂度激增,SMT方法和ILP方法难以快速求解的问题。最后,参考CR450动车组列车控制功能设计算例,以30 min为求解时间上限,分析SMT方法、ILP方法、快速求解方法在求解时间与所得调度方案资源利用率方面的性能差异。结果表明,快速求解方法能在20 min内完成1000个含零抖动和抖动约束的控制功能调度,高效调度系统资源,满足NG-TCMS快速迭代需求。研究结果可为基于NG-TCMS构建具有端到端时间确定性的列车网络控制功能及任务调度方法提供参考。
