Journal of Frontiers of Computer Science and Technology ›› 2017, Vol. 11 ›› Issue (6): 887-896.DOI: 10.3778/j.issn.1673-9418.1607018

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Scheduling Algorithm of Events with Imprecise Timestamps for CPS

LI Fangfang+, LIU Chong, YU Ge   

  1. School of Computer Science and Engineering, Northeastern University, Shenyang 110819, China
  • Online:2017-06-01 Published:2017-06-07


李芳芳+,刘  冲,于  戈   

  1. 东北大学 计算机科学与工程学院,沈阳 110819

Abstract: Cyber-physical system (CPS) is a novel intelligent system integrating computing and physical procedures, which combines computing, communication and control technologies. Event is the key element to link the cyber world and the physical world. However, the time stamp of the event is imprecise in practical applications because of data missing, mismatching of the time granularities of event from different monitoring systems, or asynchronism of events in the distributed systems and so on. By improving the scheduling algorithm of events with precise timestamps named low water mark leveraging the pruning algorithm of composite events with imprecise timestamps, this paper proposes a scheduling algorithm of events with imprecise timestamps, which supports effective scheduling of reading events and writing events in CPS. The experiments verify that the scheduling algorithm is more accurate, which guarantees providing the correct feedback of event sequences to CPS.

Key words: scheduling, events, imprecise the timestamps, cyber-physical system (CPS)

摘要: 信息物理融合系统(cyber-physical system,CPS)作为计算过程和物理过程的统一体,是集计算、通信、控制于一体的下一代智能系统。事件是连接信息世界和物理世界的重要元素,但是在实际应用中,由于数据的漏读,各个监测系统之间事件的时间粒度不匹配,来自分布式系统的事件存在着时间不同步问题等原因,会造成事件的时间戳不确定。利用时间戳不确定复杂事件的剪枝技术改进时间戳确定事件调度的低水标记算法,提出了时间戳不确定的复杂事件调度算法,并对CPS中的读写事件进行了合理调度。实验证明该算法的事件调度准确性高,保证将正确的事件执行顺序反馈给CPS系统。

关键词: 调度, 事件, 时间戳不确定, 信息物理融合系统(CPS)