CSR-SMA: Engineering Reliability into Hybrid Systems: A Compositional and Hierarchical Approach

计算机系统在规模、复杂性、分布和异构性方面发展迅速。由于这些原因，对于工程师来说，在大量资源被用于实现系统之前，在设计期间对系统属性进行定量推理变得越来越重要。这个项目关注的是软件系统架构在设计时的评估，其中一个关键属性是什么？可靠性。可靠性被定义为系统在规定的设计限制下执行其预期功能的概率。本项目中开发的方法产生了系统的多面、分层模型，它允许以增量的、可扩展的方式评估系统的可靠性。该方法将标准软件设计模型与用于评估系统可靠性的随机模型相结合。尽管存在几种软件可靠性技术，但它们要么假设运行软件系统的可用性，要么没有考虑软件系统底层固件的属性。本项目在几个代表性案例研究的背景下解决了这两个缺陷。这项研究的结果是根据两个感兴趣的指标进行评估的：可追溯性（旨在解决真实复杂系统中存在的可扩展性问题）和敏感性（旨在解决在设计时存在许多不确定性的情况下我们预测的信心问题）。该项目的结果应用于移动机器人中的实际问题，这是一个代表许多复杂、分布式和嵌入式系统的领域。这些成果也被积极地转移到课堂上。

Computer systems are growing rapidly in scale, complexity, distribution, and heterogeneity. For these reasons, it is increasingly important for engineers to reason quantitatively about a system's properties during design, before significant resources have been expended on implementing the system. This project is focusing on design-time evaluation of software systems' architectures with respect to one key property ? reliability. Reliability is defined as the probability that the system will perform its intended functionality under specified design limits. The approach developed in this project results in a multi-faceted, hierarchical model of a system, which allows assessment of the system's reliability in an incremental, scalable fashion. The approach combines standard software design models with stochastic models used to assess system reliability. Although several software reliability techniques exist, they either assume the availability of a running software system or fail to take into account the properties of the firmware underlying the software system. This project addresses both these deficiencies in the context of several representative case studies. The results of this research are evaluated along two measures of interest: tractability (intended to address scalability issues existing in real, complex systems) and sensitivity (intended to address issues of confidence in our predictions under numerous uncertainties existing at design time). The project's results are applied to real problems in mobile robotics, a domain that is representative of many complex, distributed, and embedded systems. The results are also actively transferred into the classroom.