Characterization of co-observable languages and formulas for their super/sublanguages
Characterization of co-observable languages and formulas for their super/sublanguages
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DOI:
10.1109/tac.2005.844724
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发表时间:
2005-04
影响因子:
6.8
通讯作者:
S. Takai;Ratnesh Kumar;T. Ushio
中科院分区:
文献类型:
--
作者:
S. Takai;Ratnesh Kumar;T. Ushio
We present fixed-point based characterization of several classes of co-observable languages that are of interest in the context of decentralized supervisory control of discrete-event systems, including C&P /spl or/ D&A co-observable languages, C&P co-observable languages, and D&A co-observable languages. We also provide formulas for computing super/sublanguages for each of these classes. In cases where the class of co-observable languages is not closed under intersection/union, we provide upper/lower bound of the super/sublanguage formula we present. The computation of super/sublanguages and also computation of their upper/lower bounds has lead to the introduction of other classes of co-observable languages, namely, strongly C&P co-observable languages, strongly D&A co-observable languages, locally observable languages, and strongly locally observable languages. Fixed-point based characterization of all the above language classes is also given, and their closure under intersection/union is investigated. We also study whether the fixed-point operator preserves prefix closure, relative closure (also called L/sub m/(G)-closure), and controllability.