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AN OVERVIEW OF KRL A KNOWLEDGE REPRESENTATION LANGUAGE

IP.com Disclosure Number: IPCOM000128293D
Original Publication Date: 1976-Dec-31
Included in the Prior Art Database: 2005-Sep-15

Publishing Venue

Software Patent Institute

Related People

Daniel G. Bobrow: AUTHOR [+4]

Abstract

This paper describes KRL, a Knowledge Representation Language designed for use in' understander systems. It outlines both the general,concepts which underlie our research and the details of KRL-0, an experimental implementation of some of these concepts. KRL is an attempt to integrate procedural knowledge with a broad base of declarative forms. These forms provide a variety of ways to express the logical structure of the knowledge, in order to give flexibility in associating procedures (for memory and reasoning) wiffi specific pieces of knowledge, and to control the relative accessibility of different facts and descriptions.. The formalism for declarative .knowledge is based on structured conceptual objects with associated descriptions. These objects form a network of memory units with several different sorts of linkages, each having well-specified implications for the retrieval process. Procedures can be associated directly with the internal structure of a conceptual object. This procedural attachment allows, the steps for a particular operation.to be determined by characteristics of the specific entities involved. The control structure of KRL is based on. the belief that the next generation of intelligent programs will integrate da.ta-directed and goal-directed processing by using multi-processing. It prcrvides for a priority-ordered rntilti-process agenda with explicit (user-provided) strategies for scheduling and resource allocation. It provides procedure directories which operate along with process frameworks to allow procedural parameterization of the fundamental system processes for. building, comparing, and retrieving memory structures. Future development of KRL will include integr9ting procedure definition with the descriptive formalism, Daniel Bobrow is affiliated with Xerox Palo Alto -Research Center, Palo Alto, California. rhis document is also being issued as Xerox PARC report CSL-76,4, and will appear in the journal Cognitive Science, V. 1, No. 1, 1977. This research was supported by the Advanced Research Projects of the Department of Defense under Contract MDA 903-76-C-206. The views and conclusions contained in this document are those of the author(s) and should not be interpreted as necessarily representing the official policies, either expressed or implied, of Stanford University, ARPA, or the U.S. Government. Reproduced in the U.S.A. Available from the National Technical Information Service, Springfield, Virginia 22161.

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THIS DOCUMENT IS AN APPROXIMATE REPRESENTATION OF THE ORIGINAL.

AN OVERVIEW OF KRL A KNOWLEDGE REPRESENTATION LANGUAGE

By Daniel G. Bobrow Terry Winograd

ABSTRACT

This paper describes KRL, a Knowledge Representation Language designed for use in' understander systems. It outlines both the general,concepts which underlie our research and the details of KRL-0, an experimental implementation of some of these concepts. KRL is an attempt to integrate procedural knowledge with a broad base of declarative forms. These forms provide a variety of ways to express the logical structure of the knowledge, in order to give flexibility in associating procedures (for memory and reasoning) wiffi specific pieces of knowledge, and to control the relative accessibility of different facts and descriptions.. The formalism for declarative .knowledge is based on structured conceptual objects with associated descriptions. These objects form a network of memory units with several different sorts of linkages, each having well-specified implications for the retrieval process. Procedures can be associated directly with the internal structure of a conceptual object. This procedural attachment allows, the steps for a particular operation.to be determined by characteristics of the specific entities involved.

The control structure of KRL is based on. the belief that the next generation of intelligent programs will integrate da.ta-directed and goal-directed processing by using multi-processing. It prcrvides for a priority-ordered rntilti-process agenda with explicit (user-provided) strategies for scheduling and resource allocation. It provides procedure directories which operate along with process frameworks to allow procedural parameterization of the fundamental system processes for. building, comparing, and retrieving memory structures. Future development of KRL will include integr9ting procedure definition with the descriptive formalism,

Daniel Bobrow is affiliated with Xerox Palo Alto -Research Center, Palo Alto, California. rhis document is also being issued as Xerox PARC report CSL-76,4, and will appear in the journal Cognitive Science, V. 1, No. 1, 1977.

This research was supported by the Advanced Research Projects of the Department of Defense under Contract MDA 903-76-C-206. The views and conclusions contained in this document are those of the author(s) and should not be interpreted as necessarily representing the official policies, either expressed or implied, of Stanford University, ARPA, or the U.S. Government.

Reproduced in the U.S.A. Available from the National Technical Information Service, Springfield, Virginia 22161.

Table of Contents

1. Why we are doing it 1

2. Description as the basis for a declarative language 2 a) Multiple descriptions of conceptual entities 3 b) Descriptions based on comparison to other individuals and prototypes 4 c) The detailed structure of units and perspectives 5 d) The family of descriptors 9 e) Description

Stanford Univ...