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1.
In a distributed discrete-event system with decentralized information, agents at the various sites (e.g., controllers or diagnosers) may be required to communicate in order to correctly perform some prescribed tasks. Bandwidth, power, or security constraints motivate the design of communication protocols among agents that minimize the number of required communications. This note presents an algorithm that can synthesize such a communication protocol given a set of ldquoessential transitionsrdquo that constitute the initial required communications. The synthesized communication protocol is shown to be minimal. 相似文献
2.
This paper is concerned with the elimination of unnecessary states in discrete-event system control agents. Several approaches
to supervisor reduction are studied and a new relation between agents, comparability, is defined to encapsulate most of the concepts found in the aforementioned methods. This relation is also proven to be preserved
under conjunction, which is commonly employed to determine the centralized representation of two decentralized DES supervisors.
相似文献
Karen RudieEmail: |
3.
The role of inference is added to the capabilities of decentralized supervisors in a modal logic setting for discrete-event systems. In previous work, a decentralized supervisor made a control decision through formal reasoning, using only information obtained from direct observation of a given system. The framework is extended so that when a supervisor cannot make a definitive control decision based on its own knowledge of the system, the supervisor may reason about whether other supervisors have sufficient knowledge to eventually make the correct control decision 相似文献
4.
The supervisory control of discrete-event systems under partial observation is examined. In particular, the condition of observability needed to solve the two main existing problems is investigated. A fixed-point characterization of observability is given and is shown to yield an effective test for observability where the system under consideration is specified by regular languages. A formula for the infimal prefix-closed observable superlanguage of a given language is presented. Where the system is specified by regular languages, the formula for the infimal observable language is effectively computable. 相似文献
5.
J. P. Das et al (see record 1975-08765-001) claim that A. R. Luria's (1966) distinction between simultaneous and successive modes of information processing provides a more fruitful way of classifying cognitive processes than (a) the hierarchical models of C. Burt (see record 1973-10531-001) and P. E. Vernon (see record 1963-03855-001), A. R. Jensen's (see record 1969-09740-001) Levels 1 and 2, or A. Paivio's (see record 1976-01839-001) dual coding system of imagery and verbal mediation. Their published factor analyses are surveyed, and shown to yield only partial support for their views. A broader battery of 14 tests was given to 91 university students, and responses were factor analyzed. Two of the obtained factors involved various kinds of rote memorizing, and thus could be regarded as successive processing. Four other factors did not yield a general simultaneous factor, but classified the tests under Number-Spatial, Verbal-Spatial, Perceptual Reasoning, and a specific Digit Memory factor. Overall, the 6 factors tend to follow a multiple-factor, or a hierarchical model, rather than a dichotomous classification. (French summary) (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
6.
Raman spectroscopy was used to analyze cellulose nanocrystal (CNC) -polypropylene (PP) composites and to investigate the spatial distribution of CNCs in extruded composite filaments. Three composites were made from two forms of nanocellulose (CNCs from wood pulp and the nano-scale fraction of microcrystalline cellulose) and two of the three composites investigated used maleated PP as a coupling agent. Raman maps, based on cellulose and PP bands at 1098 and 1460 cm(-1), respectively, obtained at 1 μm spatial resolution showed that the CNCs were aggregated to various degrees in the PP matrix. Of the three composites analyzed, two showed clear existence of phase-separated regions: Raman images with strong PP and absent/weak cellulose or vice versa. For the third composite, the situation was slightly improved but a clear transition interface between the PP-abundant and CNC-abundant regions was observed, indicating that the CNC remained poorly dispersed. The spectroscopic approach to investigating spatial distribution of the composite components was helpful in evaluating CNC dispersion in the composite at the microscopic level, which helped explain the relatively modest reinforcement of PP by the CNCs. 相似文献
7.
Computational complexity results are obtained for decentralized discrete-event control problems. These results generalize the earlier work of Tsitsiklis (1989), who showed that for a special class of centralized supervisory control problems under partial observation, there is an algorithm for determining in polynomial time whether or not a solution exists. The negative complexity results associated with Tsitsiklis work also carry over to the decentralized case, so that solution existence for the more general class is not decidable in polynomial time, nor does there exist a polynomial-time algorithm for producing supervisor solutions when such solutions exist 相似文献
8.
Think globally, act locally: decentralized supervisory control 总被引:5,自引:0,他引:5
Decentralized supervisory control is investigated by considering problem formulations that model systems whose specifications are given as global constraints, but whose solution is described by local controllers. A necessary and sufficient condition is given for the existence of a solution to the problem of finding decentralized supervisors that ensure that the behavior of the closed-loop system lies in a given range. Where the range of behavior can be described by regular languages, it can be effectively tested whether the decentralized control problem is solvable; in this case, a procedure is given to compute the associated supervisors 相似文献
9.
Modal logic is introduced into the modeling of discrete-event systems. Analysis within this framework includes formal reasoning about what supervisors know or do not know about a given system. This model can be used to develop control strategies that solve decentralized discrete-event control problems. When a problem cannot be solved using fully decentralized supervisors, reasoning about knowledge may provide guidelines for incorporating communication and pooled information into the model 相似文献
10.