Inspired by the pioneering work of Gilles Kahn on concurrent systems, we propose to model timed systems as a network of software components (implemented as real-time processes or tasks), each of which is specified to compute a collection of functions according to given timing constraints. We present a fixed-point semantics for this model which shows that each system function of such a network computes for a given set of (timed) input streams, a deterministic (timed) output stream. As a desired feature, such a network model can be modified by integrating new components for adding new system functions without changing the existing ones. Additionally, existing components may be replaced also by new ones fulfilling given requirements. Thanks to the deterministic semantics, a model-based approach is enabled for not only building systems but also updating them after deployment, allowing for efficient analysis techniques such as model-in-the-loop simulation to verify the complete behaviour of the updated system.
翻译:在Gilles Kahn关于并行系统的开创性工作启发下,我们提议将定时系统建为软件元件网络(作为实时程序或任务实施),每个系统指定用来根据特定时间限制计算一系列功能。我们为这个模型提出固定点的语义,表明这样一个网络的每个系统功能都计算出一套特定(定时)输入流,一种确定性(定时)输出流。作为一个理想的特征,这样的网络模型可以通过整合新的元件来修改,添加新的系统元件而不改变现有元件。此外,现有的元件也可以被新的符合特定要求的元件所取代。由于定时语,基于模型的方法不仅能够建立系统,而且能够在部署后对其进行更新,从而允许有效的分析技术,例如模拟操作模拟,以核实更新系统的完整行为。