Methodologies for real-time discrete-event simulation

实时系统（RTS）是非常先进的计算机系统应用程序，其中硬件和软件组件以紧密的方式相互作用。这种系统的手工开发非常耗时，容易出错，而且成本昂贵。针对RTS开发已经提出了不同的正式方法，但随着系统复杂性的增加，这些方法很难应用。建模和仿真（M&S）技术和工具已经被提出来解决这个问题，并且已经被证明对验证和验证RTS非常有用，包括它们与之交互的环境。我们想研究使用基于模型的方法开发RTS的系统方法和自动化工具。我们感兴趣的是定义新的理论、方法和技术来构建仿真模型，这些模型以后可以应用于实时环境中，以及将复杂的物理系统与RTS集成在一起的系统中，将正式建模技术与仿真相结合。虽然在这方面已经作出了一些努力，但仍有许多问题有待解决。主要问题是，所提出的解决方案都没有考虑到瞬态过载、时序约束检查和容错问题。这需要定义新的理论、算法和工具，以保证在指定的时间限制内对输入的响应，支持故障并提供优雅的退化。我们还将分析如何定义实时模型，并为执行模型提供自动验证，包括连续和混合系统的方法。我们将构建一套可用于开发实时软件的工具，并与硬件在环进行模拟，这将用作我们理论框架的概念验证。该研究具有影响各种应用领域（通信、应急规划、交通控制、生物医学等）的潜力。

Real-time systems (RTS) are very advanced computer system applications with hardware and software components interacting in a tight fashion. The manual development of this kind of systems is time consuming, error prone, and expensive. Different formal methods have been proposed for RTS development, but they have shown to be difficult to apply as the complexity of the system scales up. Modeling and Simulation (M&S) techniques and tools have been proposed to address this issue and have been proven to be useful to verify and validate RTS, including the environment they interact with. We want to investigate systematic methods and automated tools to develop RTS using a model-based methodology. We are interested in defining new theories, methods and techniques for building simulation models that can later be applied in real-time environments, and in systems integrating complex physical systems with RTS, combining formal modelling techniques and simulation. Although several efforts exist in this area, many questions remain open. The main issue is that none of the proposed solutions has considered problems of transient overloading, checking of timing constraints, and fault tolerance. This requires defining new theories, algorithms and tools to guarantee responses to inputs within specified time constraints, supporting faults and providing graceful degradation. We will also analyze how to define real-time models, and we will provide automatic verification for the executing models, including methods for continuous and hybrid systems. We will build a set of tools that can be applied to develop real-time software, and simulations with hardware in-the-loop, which will be used as a proof-of-concept of our theoretical framework. The research has the potential to influence a variety of applications fields (communication, emergency planning, traffic control, biomedical, etc).