Using Action-Based Hierarchies for Real-Time Diagnosis

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Citation: David Ash and Barbara Hayes-Roth. (1995) Using Action-Based Hierarchies for Real-Time Diagnosis. In KSL-95-02, January,1995.

Publication techreport ( Edit )
type Technical Report
bibtype techreport
Bibtex basics
author David Ash and Barbara Hayes-Roth
title Using Action-Based Hierarchies for Real-Time Diagnosis
number KSL-95-02
institution Knowledge Systems, AI Laboratory
address Stanford, CA, USA
year 1995
month January
Bibtex more
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abstract An intelligent agent diagnoses perceived problems so that it can respond to them appropriately. Basically, the agent performs a series of tests whose results discriminate among competing hypotheses. Given a specific diagnosis, the agent performs the associated action. Using the traditional information-theoretic heuristic to order diagnostic tests in a decision tree, the agent can maximize the information obtained from each successive test and thereby minimize the average time (number of tests) required to complete a diagnosis and perform the appropriate action. However, in real-time domains, even the optimal sequence of tests cannot always be performed in the time available. Nonetheless, the agent must respond. For agents operating in real-time domains, we propose an alternative action-based approach in which: (a) each node in the diagnosis tree is augmented to include an ordered set of actions, each of which has positive utility for all of its children in the tree; and (b) the tree is structured to maximize the expected utility of the action available at each node.Upon perceiving a problem, the agent works its way through the tree,performing tests that discriminate among successively smaller subsets of potential faults. When a deadline occurs, the agent performs the best available action associated with the most specific node it has reached so far. Although the action-based approach does not minimize the time required to complete a specific diagnosis, it provides positive-utility responses, with step-wise improvements in expected utility, throughout the diagnosis process. We present theoretical and empirical results contrasting the advantages and disadvantages of the information-theoretic and action-based approaches.

KSL Technical Report ID: KSL-95-02
Facts about Using Action-Based Hierarchies for Real-Time DiagnosisRDF feed
Abstract An intelligent agent diagnoses perceived p … An intelligent agent diagnoses perceived problems so that it can respond to them appropriately. Basically, the agent performs a series of tests whose results discriminate among competing hypotheses. Given a specific diagnosis, the agent performs the associated action. Using the traditional information-theoretic heuristic to order diagnostic tests in a decision tree, the agent can maximize the information obtained from each successive test and thereby minimize the average time (number of tests) required to complete a diagnosis and perform the appropriate action. However, in real-time domains, even the optimal sequence of tests cannot always be performed in the time available. Nonetheless, the agent must respond. For agents operating in real-time domains, we propose an alternative action-based approach in which: (a) each node in the diagnosis tree is augmented to include an ordered set of actions, each of which has positive utility for all of its children in the tree; and (b) the tree is structured to maximize the expected utility of the action available at each node.Upon perceiving a problem, the agent works its way through the tree,performing tests that discriminate among successively smaller subsets of potential faults. When a deadline occurs, the agent performs the best available action associated with the most specific node it has reached so far. Although the action-based approach does not minimize the time required to complete a specific diagnosis, it provides positive-utility responses, with step-wise improvements in expected utility, throughout the diagnosis process. We present theoretical and empirical results contrasting the advantages and disadvantages of the information-theoretic and action-based approaches. ion-theoretic and action-based approaches.
Address Stanford, CA, USA  +
Author David Ash and Barbara Hayes-Roth  +
Bibtype techreport  +
Has author David Ash and Barbara Hayes-Roth  +
Has identifier KSL-95-02  +
Has publishing details January,1995  +
Has title Using Action-Based Hierarchies for Real-Time Diagnosis  +
Has where published KSL-95-02  +
Has year 1995  +
Institution Knowledge Systems, AI Laboratory  +
Ksl tr id KSL-95-02  +
Month January  +
Number KSL-95-02  +
Process note NO  +
Title Using Action-Based Hierarchies for Real-Time Diagnosis  +
Year 1995  +
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