Rational Interpolation for Real-Time System Analysis

在过去的几年中，嵌入式应用中的实时系统得到了迅速发展。许多这样的系统被用于生命攸关和其他重要的应用中，在这些应用中，计算机不能按时完成某些任务可能会造成灾难性的后果。因此，需要准确地评估这类计算机的可靠性。实时系统中的故障可能由于时间以及硬件故障等传统原因而发生。时间超时通常是计算机各种元素之间一系列复杂交互的结果，例如单个应用程序任务、操作系统、调度算法、系统架构、组件瞬时和永久故障特征等。在分析模型中，如果不简化假设，就很难考虑到这种相互作用，这会引起对模型准确性和有效性的质疑。此外，验证分析模型的传统模拟非常困难，因为被验证的故障率往往非常低：系统故障率低至。涉及000000001。一个早期nsf资助的项目开发了Rational Interpolation技术，并展示了它在许多计算应用中的实用性。它创建了一个框架，在这个框架中可以解决各种困难的建模、控制和优化问题。结果表明，Rational Interpolation是一个强大的工具，可以用来补充其他可靠性和性能评估机制，特别是在预测非常低的故障率方面。这个项目将涉及基于实时系统的Rational插值的技术和工具的开发。虽然重点将放在实时系统上，但研究结果也有望用于评估其他应用中的计算机，比如随机算法。

Real-time systems in embedded application have proliferated over the past few years. Many such systems are being used in life-critical and other important applications, where the failure of the computer to meet some deadlines can have disastrous consequences. The need therefore exists to accurately evaluate the reliability of such computers. Failure in a real-time system can occur due to timing as well as to traditional causes such as hardware failure. Timing overruns are often the consequence of a complicated series of interactions between various elements of the computer, such as individual application tasks, the operating system, the scheduling algorithm, the system architecture, component transient and permanent failure characteristics among other things. It is hard to take account of such interactions in analytical models without resorting to simplifying assumptions which raise questions about the models' accuracy and validity. Furthermore, traditional simulation to validate analytical models is very difficult because the failure rates that are being validated tend to be very low: system failure rates as low as .000000001 are involved. An earlier NSF-funded project developed the Rational Interpolation technique, and showed its usefulness in may compute applications. It created a framework in which various difficult modeling, control, and optimization issues can be attacked. The results indicate that Rational Interpolation is a powerful tool that can be used to complement other mechanisms of reliability and performance evaluation, especially in predicting very low failure rates. This project will involve the development of techniques and tools based on Rational Interpolation for real-time systems. While the focus will be on real-time systems, the results are expected to be useful in evaluating computers in other applications as well, such as random algorithms.