Methodologies for real-time discrete-event simulation

实时系统(RTS)是硬件和软件组件以紧密方式交互的非常高级的计算机系统应用。这种系统的手动开发既耗时又容易出错，而且成本高昂。对于RTS开发，已经提出了不同的形式化方法，但随着系统复杂性的增加，它们被证明很难应用。建模与仿真(M&S)技术和工具已被提出用于解决这一问题，并已被证明对验证和验证RT，包括它们与之交互的环境是有用的。我们希望研究系统方法和自动化工具，以使用基于模型的方法来开发RTS。我们感兴趣的是定义新的理论、方法和技术来建立稍后可以在实时环境中应用的仿真模型，以及将形式建模技术和仿真相结合将复杂物理系统与RTS相结合的系统。尽管在这一领域已经做出了一些努力，但许多问题仍然悬而未决。主要问题是，提出的解决方案中没有一个考虑到瞬时过载、时序约束检查和容错等问题。这需要定义新的理论、算法和工具，以保证在规定的时间限制内对输入做出响应，支持故障并提供优雅的降级。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，包括连续系统和混合系统的方法。我们将构建一套可用于开发实时软件和硬件在环仿真的工具，这些工具将用作我们的理论框架的概念验证。这项研究有可能影响到各种应用领域(通信、应急计划、交通控制、生物医学等)。

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).