CPS: Medium: Resource-Aware Hierarchical Runtime Verification for Mixed-Abstraction-Level Systems of Systems

驾驶飞机通常被描述为几个小时的极度无聊，不时被极度恐惧所打断。同样，一个航天器在向一个遥远的目标飞行时，基本上保持休眠状态，但需要定期加强活动，以维持和保持在航线上。飞机和航天器是复杂的系统，它们必须无缝地协同工作，通过精心编排的层次结构来切换控制，这些层次结构代表不同的抽象层次，例如，以事件的不同时间尺度为例。每一个机载系统都有其自身的核查挑战;面对潜在的意外环境输入，核查所有这些系统同时演奏的交响乐尤其令人生畏。我们可以用高效的运行时验证引擎来补充设计时验证，但是它们需要增长，以便能够推理复杂系统的系统的分层性质，其中单个需求可能需要封装多个抽象级别。最终结果必须能够在系统资源限制内以真实的时间执行。用于运行时验证的现有工具不能够遵守通过在真实的系统（或在真实的任务中）上运行它们而施加的约束，并且没有参数来将它们的计算需求集中在对系统安全最有影响的任务上。实现安全的CPS依赖于开发实时验证的工具和算法，将真实的安全检查集成到其控制架构和动态环境中。本项目采用形式化方法，控制理论，硬件-软件集成和软件工程的技术来设计运行时监视器，以检查系统的网络物理系统，而不会干扰其正常运行。该项目设计，分析和实现基本的运行时验证技术，通过处理三个一般和正交的问题：混合抽象级别的粒度规范，资源意识，以确保非侵入性的运行时监视器，并增强监视器与模型预测，使在截止日期缓解触发。关键的创新源于这个严格的基础，建立一个新的正式语义层次，混合抽象级规范，并评估正式规范，而不干扰系统的正常运行，同时最大限度地利用资源的现实约束内的嵌入式CPS。该项目将新理论推广到分层功能需求的规范模式中，并合成预测模型，以更好地，更自动地创建运行时验证配置，以满足现代CPS的可扩展性需求。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Piloting an aircraft is popularly described as hours of abject boredom punctuated by periods of abject terror. Similarly, a spacecraft in transit to a distant target remains largely dormant but for periodic heightened activity required for maintenance and staying on course. Aircraft and spacecraft are complex systems of systems that must seamlessly work together, switching control through a carefully orchestrated hierarchy representing different levels of abstraction, e.g., exemplified by different timescales for events. Each on-board system presents its own verification challenge; verifying that the symphony of all of them playing together at the same time, in the face of potentially unexpected environmental inputs, is particularly daunting. We can supplement design-time verification with efficient runtime verification engines, but they need to grow to be able to reason about the hierarchical nature of complex systems-of-systems, where single requirements may need to encapsulate multiple levels of abstraction. The final result must be able to execute in real time, within system resource constraints. Existing tools for runtime verification aren't capable of obeying constraints imposed by running them on real systems (or in real missions), and don't have parameters to focus their computational demands on the tasks most impactful on system safety. Achieving safe CPS depends on growing the tools and algorithms of real-time verification to integrate realistic safety checks into their control architectures and dynamic environments.This project adapts techniques from formal methods, control theory, hardware-software integration, and software engineering to design runtime monitors that inspect cyber-physical systems of systems without interfering with their normal operation. The project designs, analyzes, and implements fundamental runtime verification techniques by dealing with three general and orthogonal problems: mixed-abstraction-level granularity in specifications, resource-awareness to ensure non-intrusiveness of runtime monitors, and augmenting monitors with model-prediction to enable on-deadline mitigation triggering. Key innovations stem from this rigorous foundation in establishing a new formal semantics for hierarchical, mixed-abstraction-level specification, and evaluating formal specifications without interfering with the system's normal operation, while maximizing utilization of resources within realistic constraints of embedded CPS. The project generalizes the new theory into specification patterns for hierarchical functional requirements and synthesize predictive models to enable better, more automated creation of runtime verification configurations to meet scalability demands of modern CPS. Flight tests of small aircraft swarms are used to validate this approach.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.