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Exploiting Temporal Knowledge to Organize Constraints

IP.com Disclosure Number: IPCOM000147986D
Original Publication Date: 1983-Jul-19
Included in the Prior Art Database: 2007-Mar-28

Publishing Venue

Software Patent Institute

Related People

Smith, Stephen F.: AUTHOR [+2]

Abstract

Intelligent Systems Laboratory ?l~c Robotics Iristitute Carnegie-Mellon University Pittsburgh, Pennsylvania 15213 19 July 1983 Exploiting Temporal Know Iedg to Organize Constraints e Stephen F. Smith . Intelligent Systems Laboratory The Robotics InstituteCarnegie-Mellon University Pittsburgh, Pa. 15213 19 July 1983 Abstract: This paper examines the role of temporal knowledge in regard to th representation and utilizstion of constraints within time dependent problem domains. We first consider the representation of constraints whose, interpretations may vary in different tem oral regions of the solution space. A representation that organizes constraint variants via the te poral relationships among them is presented and seen to support a simple mechanism for deterqining the applicable variant at any point in time. We then turn our attention to the management constraints that are dynamically imposed as various commitments are made by theresources are allocated to activities in a plan). Constraint propagationinsure consistency in the hypotheses under development aretechniques are driven by the temporal relationships present inmotivated by ongoing research with ISIS, an intelligentbeing applied to the problem of scheduling job shops,from this domain.

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Exploiting Temporal Knowledge to
Organize Constraints
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Intelligent Systems Laboratory
?l~c Robotics Iristitute Carnegie-Mellon University Pittsburgh, Pennsylvania 15213

19 July 1983

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Exploiting Temporal Know Iedg

to Organize Constraints

Stephen F. Smith .

Intelligent Systems Laboratory

  The Robotics Institute
Carnegie-Mellon University

Pittsburgh, Pa. 15213

19 July 1983

 Abstract: This paper examines the role of temporal knowledge in regard to th representation and utilizstion of constraints within time dependent problem domains. We first consider the representation of constraints whose, interpretations may vary in different tem oral regions of the solution space. A representation that organizes constraint variants via the te poral relationships

among them is presented and seen to support a simple mechanism for deterqining the applicable variant at any point in time. We then turn our attention to the management constraints that are dynamically imposed as various commitments are made by the
resources are allocated to activities in a plan). Constraint propagation
insure consistency in the hypotheses under development are
techniques are driven by the temporal relationships present in
motivated by ongoing research with ISIS, an intelligent
being applied to the problem of scheduling job shops,
from this domain.

Copyright @ 1983 Intelligent Systems Laboratory

This research was supported by the Air Force Office of Scientific Rese rch under contract F49620-82-K0017.

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Table of Contents

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1, Introduction
2. Background
3. A representational framework for modeling time
3.1. Primitive temporal objects
3.2. Primitive temporal relations
4. Temporal knowledge as a basis for constraint resolution
4.1. Time varying constraints
4.2. An example: representing shift constraints
5. Ternporal knowledge as a basis for constraint propagation
5.1. Multiple descriptions of activities and resources
5.2. Maintaining the consistency of resource reservations through constraints
5.2.1. Potential inconsistencies and associated constraint types
5.2.2. Propagating a commitment to a new resource reservation.
5.2.3. Propagating the removal a resource reservation
5.2.4. Invalidating and restoring resource reservations
6. Summary Acknowledgements .
References
I. The SRL schema construct

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