Showing papers by "Raymond H. Kwong published in 1999"
07 Dec 1999
TL;DR: A framework is introduced for passive online fault diagnosis in timed discrete-event systems (TDES) by incorporating timing information, which enhances the accuracy of diagnosis and leads to significant reduction in online computing requirements and the size of the diagnoser at the expense of more off-line design calculations.
Abstract: A framework is introduced for passive online fault diagnosis in timed discrete-event systems (TDES). It extends the previous work of the authors (1999) on a state-based approach to fault diagnosis by incorporating timing information. This enhances the accuracy of diagnosis. In this methodology instead of directly extending the existing framework to TDES, an alternative approach is taken which, in many cases, leads to significant reduction in online computing requirements and the size of the diagnoser at the expense of more off-line design calculations.
70 citations
01 Jan 1999
TL;DR: Instead of directly extending the framework to timed discrete-event systems, it takes an alternative apporach which leads to significant reduction in on-line computing power requirements and in the size of the diagnoser at the expense of more off-line design calculations.
Abstract: In this paper, we propose a framework for fault diagnosis in discrete-event systems In this approach, the system and the diagnoser (the fault detection system) do not have to be initialized at the same time Furthermore, no information about the state or even the condition (failure status) of the system before the initiation of diagnosis is required First, a state-based approach for on-line passive fault diagnosis in finite-state automata is presented The design of the fault detection system, in the worst case, has exponential time complexity A model reduction scheme with polynomial time complexity is introduced to reduce the computational complexity of the design Next we consider the use of timing information to improve the accuracy of diagnosis Instead of directly extending our framework to timed discrete-event systems, we take an alternative apporach which leads to significant reduction in on-line computing power requirements and, in many cases, in the size of the diagnoser at the expense of more off-line design calculations We also discuss the issue of diagnosability of failures in our framework
19 citations
TL;DR: In this article, constrained supremum and supremum operators are introduced to obtain a general procedure for computing supremal elements of upper semilattices, such as supremal (A, B)-invariant subspaces and supremal controllable sublanguages.
Abstract: Constrained supremum and supremum operators are introduced to obtain a general procedure for computing supremal elements of upper semilattices. Examples of such elements include supremal (A, B)-invariant subspaces in linear system theory and supremal controllable sublanguages in discrete-event system theory. For some examples, we show that the algorithms available in the literature are special cases of our procedure. Our iterative algorithms may also provide more insight into applications; in the case of supremal controllable subpredicate, the algorithm enables us to derive a lookahead policy for supervisory control of discrete-event systems.
9 citations