Failure Diagnosis of Modular and Decentralized Discrete Event Systems

随着对复杂技术系统性能和可靠性要求的日益严格，需要开发系统的方法来及时和准确地诊断系统故障。几年来，我们一直在开发一种使用离散事件系统(DES)方法的集中式故障诊断方法。该方法已成功地应用于工业领域。我们建议在已有的DES集中式和分散式故障诊断结果的基础上，针对可能发生间歇性故障的具有模块化和分布式体系结构的大型复杂系统，开发一种全面的故障诊断方法。我们的主要关注点是系统的在线诊断，即在系统运行时，而不是在系统不运行时对系统进行离线测试。我们的研究将包括：(1)集中式体系结构中间歇性故障的诊断；(P2)在协调分散体系结构中处理通信延迟；(P3)开发分散故障诊断的新技术，在不同站点的本地诊断模块之间进行通信；以及(P4)开发在故障诊断中利用系统结构的模块化的新技术。这些问题是基于从我们的方法的工业应用中收到的反馈，目的是扩大其适用性。问题(PI)和(P2)将直接基于我们先前在用于故障诊断的集中式和协调的分散式体系结构方面的工作。问题(P3)和(P4)旨在以新的方向扩展我们的方法论的范围。在问题(P3)中，我们打算利用站点之间的通信来增强分散信息系统中的诊断能力。在问题(P4)中，我们打算利用系统结构来实现模块化系统故障诊断中的计算节省。从我们对上述问题的通用形式化方法中获得的见解将为设计降低复杂性且仍具有良好性能的自组织诊断协议提供指导。因此，本方案中描述的研究将对各种复杂工程和计算系统的故障诊断协议的系统设计产生重大影响。

The increasingly stringent requirements on performance and reliability of complex technological systems have necessitated the development of systematic methods for timely and accurate diagnosis of system faults. For several years, we have been developing a methodology for centralized failure diagnosis using a discrete event systems (DES) approach. This methodology has been successfully applied in industry.We propose to build on our previous results on centralized and decentralized failure diagnosis of DES in order to develop a comprehensive methodology for failure diagnosis of large-scale complex systems with modular and distributed architectures where intermittent failures may occur. Our primary focus is the on-line diagnosis of the system, i.e., while it is operating, as opposed to off-line testing of a system when it is not under operation. Our research will include:(Pl) diagnosis of intermittent failures in the context of centralized architectures;(P2) dealing with communication delays in the context of coordinated decentralized architectures;(P3) development of new techniques for decentralized failure diagnosis with communication among local diagnostic modules at different sites; and (P4) development of new techniques exploiting the modularity of the system structure in failure diagnosis. These problems are based on feedback received from industrial applications of our methodology and aim at extending its applicability. Problems (PI) and (P2) will be directly based on our prior work on centralized and coordinated decentralized architectures for failure diagnosis. Problems (P3) and (P4) aim at extending the scope of our methodology in new directions. In Problem (P3) we intend to exploit communication among sites to enhance diagnostic capabilities in systems with decentralized information. In Problem (P4) we intend to exploit system structure to achieve computational savings in failure diagnosis of modular systems.The insight gained from our generic formal approach to the above-mentioned problems will provide the guidelines for the design of ad hoc diagnostic protocols that will have reduced complexity and still perform well. Therefore the research described in this proposal will have a significant impact on the systematic design of failure diagnosis protocols for a wide variety of complex engineering and computing systems.