This study presents a novel discrete-event systems (DES) modeling framework to address real-time system (RTS) with sporadic, periodic, and non-repetitive real-time tasks. Our approach is organized in three steps. First, the effect of individual timing parameters of each task, such as job arrival and deadlines, are represented by modular DES. Second, we choose the required modules for the specific RTS at hand to compose an overall model. Third, we utilize supervisory control to find all schedules that are consistent with the timing requirements of all tasks. In contrast to fixed task priorities, we address general preemption relations represented by a preemption matrix and thereby implement priority-free conditionally-preemptive (PFCP) real-time scheduling. As a particular feature of the closed-loop configuration, the schedules obtained refer to the actual job execution time as opposed to upper and lower bounds. We illustrate our approach by a real-world example in the context of an automated manufacturing system.

中文翻译：

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基于SCT的具有精确任务执行时间的模块化实时系统的无优先级条件抢占调度

本研究提出了一种新颖的离散事件系统 (DES) 建模框架，以解决具有零星、周期性和非重复性实时任务的实时系统 (RTS)。我们的方法分为三个步骤。首先，每个任务的单独计时参数的影响，例如作业到达和截止日期，由模块化 DES 表示。其次，我们为手头的特定 RTS 选择所需的模块以组成整体模型。第三，我们利用监督控制找到与所有任务的时间要求一致的所有时间表。与固定任务优先级相比，我们解决了由抢占矩阵表示的一般抢占关系，从而实现了无优先级的条件抢占（PFCP）实时调度。作为闭环配置的一个特殊功能，获得的时间表是指实际作业执行时间，而不是上限和下限。我们在自动化制造系统的背景下通过一个真实世界的例子来说明我们的方法。