Failure Diagnosis Of Discrete Event Systems Research Articles

Robustly distributed diagnosis of discrete-event systems and its application to Alipay transaction systems

In most of existing literature, it is assumed that all of the sensors can work normally. However in some situations, several sensors occur abnormal behavior or stuck at faults such that prior diagnosable decisions may not hold. By this regard, we address the problem of robustly distributed failure diagnosis of discrete-event systems with observation losses in this paper. In order to ensure diagnosability, the notion of robustly diagnosability is proposed in the distributed framework. Motivated by earlier works, new communication models and dilation operators are constructed, based on which the robustly distributed diagnosis problem is converted to a distributed diagnosis problem. One algorithm for the verification of robustly distributed diagnosis is proposed. Followed by it, a necessary and sufficient condition for the robustly diagnosability is presented. Finally, a part of Alipay transaction systems as an application is used to illustrate the construction of some automata and the verification algorithm.

Failure Diagnosis of Discrete-Event Systems With Linear-Time Temporal Logic Specifications

The paper studies failure diagnosis of discrete-event systems (DESs) with linear-time temporal logic (LTL) specifications. The LTL formulas are used for specifying failures in the system. The LTL-based specifications make the specification specifying process easier and more user-friendly than the formal language/automata-based specifications; and they can capture the failures representing the violation of both liveness and safety properties, whereas the prior formal language/automaton-based specifications can capture the failures representing the violation of only the safety properties (such as the occurrence of a faulty event or the arrival at a failed state). Prediagnosability and diagnosability of DESs in the temporal logic setting are defined. The problem of testing prediagnosability and diagnosability is reduced to the problem of model checking. An algorithm for the test of prediagnosability and diagnosability, and the synthesis of a diagnoser is obtained. The complexity of the algorithm is exponential in the length of each specification LTL formula, and polynomial in the number of system states and the number of specifications. The requirement of nonexistence of unobservable cycles in the system, which is needed for the diagnosis algorithms in prior methods to work, is relaxed. Finally, a simple example is given for illustration.

Coordinated Decentralized Protocols for Failure Diagnosisof Discrete Event Systems

We address the problem of failure diagnosis in discrete event systems with decentralized information. We propose a coordinated decentralized architecture consisting of local sites communicating with a coordinator that is responsible for diagnosing the failures occurring in the system. We extend the notion of diagnosability, originally introduced in Sampath et al. (1995) for centralized systems, to the proposed coordinated decentralized architecture. We specify three protocols that realize the proposed architecture; each protocol is defined by the diagnostic information generated at the local sites, the communication rules used by the local sites, and the coordinator‘s decision rule. We analyze the diagnostic properties of each protocol. We also state and prove conditions for a language to be diagnosable under each protocol. These conditions are checkable off-line. The on-line diagnostic process is carried out using the diagnosers introduced in Sampath et al. (1995) or a slight variation of these diagnosers. The key features of the proposed protocols are: (i) they achieve, each under a set of assumptions, the same diagnostic performance as the centralized diagnoser; and (ii) they highlight the ’’performance vs. complexity‘‘ tradeoff that arises in coordinated decentralized architectures. The correctness of two of the protocols relies on some stringent global ordering assumptions on message reception at the coordinator‘s site, the relaxation of which is briefly discussed.