Knowledge-Based Real Time Control: The Use of Abstraction to Satisfy Deadlines

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Citation: A. Vina and Barbara Hayes-Roth. (1991) Knowledge-Based Real Time Control: The Use of Abstraction to Satisfy Deadlines. In KSL-91-57, September,1991.

Publication techreport ( Edit )
type Technical Report
bibtype techreport
Bibtex basics
author A. Vina and Barbara Hayes-Roth
title Knowledge-Based Real Time Control: The Use of Abstraction to Satisfy Deadlines
number KSL-91-57
institution Knowledge Systems, AI Laboratory
year 1991
month September
Bibtex more
Access Paper
abstract [[abstract::In this paper we address the use of model-based knowledge representation andreasoning techniques under a blackboard framework in real time computer-basedcontrol. Representing knowledge using models is one of the most powerful waysto codify the controller's knowledge about the system being controlled. Byusing a model and the current values for the monitored parameters, thecontroller can base all their process automation tasks on the outcomes of aprecise simulation of the system behavior. But models have a seriousdrawback: they have difficulty accommodating normal quantities of componentsfound in current systems. To overcome this problem when working under realtime constraints, we propose a techniques which allows a control system toachieve real time performance by means of the following computational steps:(1) starting with the basic user-defined domain model, the engineerprecomputes a hierarchy of abstract models, at increasing levels ofabstraction, using the aggregation of causal links to guide the abstractionprocess; (2) continuing off-line, the engineer estimates the worst-caseprocessing time for every model in the hierarchy; (3) on-line, the controlleruses the time constraints of the situation and the worst-case processing timesof the models to choose one model with the level of abstraction that willguarantee deadline satisfaction; and (4) the controller performs systemsimulation using the selected model. We have used the BB1 blackboardarchitecture [Hayes-Roth, 1985; 1988; 1990] to implement our work. Theresults, however, can easily be transferred to another computationalframework.|In this paper we address the use of model-based knowledge representation andreasoning techniques under a blackboard framework in real time computer-basedcontrol. Representing knowledge using models is one of the most powerful waysto codify the controller's knowledge about the system being controlled. Byusing a model and the current values for the monitored parameters, thecontroller can base all their process automation tasks on the outcomes of aprecise simulation of the system behavior. But models have a seriousdrawback: they have difficulty accommodating normal quantities of componentsfound in current systems. To overcome this problem when working under realtime constraints, we propose a techniques which allows a control system toachieve real time performance by means of the following computational steps:(1) starting with the basic user-defined domain model, the engineerprecomputes a hierarchy of abstract models, at increasing levels ofabstraction, using the aggregation of causal links to guide the abstractionprocess; (2) continuing off-line, the engineer estimates the worst-caseprocessing time for every model in the hierarchy; (3) on-line, the controlleruses the time constraints of the situation and the worst-case processing timesof the models to choose one model with the level of abstraction that willguarantee deadline satisfaction; and (4) the controller performs systemsimulation using the selected model. We have used the BB1 blackboardarchitecture [Hayes-Roth, 1985; 1988; 1990] to implement our work. Theresults, however, can easily be transferred to another computationalframework.]]

KSL Technical Report ID: KSL-91-57
Facts about Knowledge-Based Real Time Control: The Use of Abstraction to Satisfy DeadlinesRDF feed
Author A. Vina and Barbara Hayes-Roth  +
Bibtype techreport  +
Has author A. Vina and Barbara Hayes-Roth  +
Has identifier KSL-91-57  +
Has publishing details September,1991  +
Has title Knowledge-Based Real Time Control: The Use of Abstraction to Satisfy Deadlines  +
Has where published KSL-91-57  +
Has year 1991  +
Institution Knowledge Systems, AI Laboratory  +
Ksl tr id KSL-91-57  +
Month September  +
Number KSL-91-57  +
Process note NO  +
Title Knowledge-Based Real Time Control: The Use of Abstraction to Satisfy Deadlines  +
Year 1991  +
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