ABSTRACT Cyber-Physical Systems (CPSs) use sensors and actuators to interface between an embedded system and the physical world. The time-continuous domain of the physical world should be periodically sampled by real-time tasks in an embedded system to preserve its dynamic properties in the time-discrete domain. Because the task execution pattern may vary during runtime, a jitter in the execution of a real-time task hinders the periodicity of its execution. The effects of jitters in CPSs are difficult to determine when the premises of the Nyquist-Shannon sampling theorem are not satisfied. This paper proposes using frequency domain analysis to determine the perturbations that a real-time system produces on real-world applications; accordingly, the paper defines both a design and an evaluation criterion for real-time systems in CPS applications. The Fixed Priority discipline is analysed through simulations to conclude that no special design techniques are required when the utilization factors are less than 20%.

中文翻译：

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网络物理应用中的嵌入式实时系统：一种频域分析方法

摘要 网络物理系统 (CPS) 使用传感器和执行器来连接嵌入式系统和物理世界。物理世界的时间连续域应该由嵌入式系统中的实时任务定期采样，以保持其在时间离散域中的动态特性。由于任务执行模式在运行时可能会发生变化，因此实时任务执行中的抖动会阻碍其执行的周期性。当 Nyquist-Shannon 采样定理的前提不满足时，很难确定 CPS 中抖动的影响。本文建议使用频域分析来确定实时系统在实际应用中产生的扰动；因此，本文定义了 CPS 应用中实时系统的设计和评估标准。