overview of SRKB

Tom Gruber <gruber@HPP.Stanford.EDU>
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Date: Thu, 5 May 1994 18:10:21 -0800
To: srkb@cs.umbc.edu
From: Tom Gruber <gruber@HPP.Stanford.EDU>
Subject: overview of SRKB
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Here is a overview of the SRKB working group with information about where
to find more information.   This text is maintained with the mail list
server, and the latest version is always obtainable by sending the message
"info srkb" to majordomo@cs.umbc.edu.


The SRKB working group of the ARPA Knowledge Sharing Effort

  Mailing list: srkb@cs.umbc.edu

SRKB stands for Shared Reusable Knowledge Bases.  This name reflects the
original motivation of the working group as a part of the ARPA Knowledge
Sharing Effort.  The main focus of our discussion and efforts has been on
shared ontologies.

Ontologies are agreements about shared conceptualizations.  Shared
conceptualizations include conceptual frameworks for modeling domain
knowledge; content-specific protocols for communication among interoperating
agents; and agreements about the representation of particular domain theories.
In the knowledge sharing context, ontologies are specified in the form of
definitions of representational vocabulary.  A very simple case would be a
type hierarchy, specifying classes and their subsumption relationships.
Relational database schemata also serve as ontologies by specifying the
relations that can exist in some shared database and the integrity constraints
that must hold for them.  In general, ontologies are equivalent to logical
theories, such as axiomatizations of time.

Other working groups in the Knowledge Sharing Effort have produced
specifications for a language with which to write these agreements (the KIF
interlingua) and a communication protocol by which interoperating systems can
exchange information (the KQML agent communication language).  It is the
charter of the SRKB group to gather, study, and coordinate the development
of the
content-specific agreements we call ontologies.

The SRKB group is open to all interested parties, and this mailing list is the
official channel for communication.  However, most of the work is done in
smaller, self-organizing, special-interest groups focusing on specific topics.
For example, one group has been working on engineering ontologies, including
foundations for modeling and simulation.  Another has been working on
representations for processes, such as work flow in an enterprise.  There is a
group focused on ontologies pertaining to planning and scheduling, and another
is surveying and specifying formalizations of time.

Ontologies can be written in many forms, ranging from informal dictionaries to
formal axiomatizations, and including specifications that mix informal and
formal definitions.  The Knowledge Sharing Effort is committed to
specifications that are declarative and independent of particular
implementations or inference procedures.  We have a mechanism for sharing
ontologies and software for analyzing and publishing ontology specifications.
This is the KIF language and the Ontolingua system.  Ontolingua operates on
ontologies written in the KIF language and provides translations into several
implemented knowledge representation systems.  It also can be used to generate
cross-indexed, hypertext reports on the ontologies.

A set of example ontologies is maintained as part of the Knowledge Sharing
Effort library.  This library is publicly accessible on the internet by ftp
 and World Wide Web protocols.  The ontologies are available in several
representation languages, including KIF, and are also compiled into a large
web of cross-linked hypertext reports.  The library also includes access to
related technical papers, free software, and specification documents (e.g.,
for KIF and KQML). The address of this library is

   By World Wide Web,

   By FTP,
    Host: ksl.stanford.edu
    Directory: /pub/knowledge-sharing

The procedure for posting ontologies is simple.  Parties interested in a
particular ontology area, such as representations of time or processes,
announce their intent and invite participation on the SRKB list.  They gather,
study, and develop ontologies that specify agreements about the area of
interest.  For example, a group interested in time might develop several
ontologies, each corresponding to a different model of time, and also show
there lationships among them.  Then any ontologies that are specified in legal
KIF can be posted to the ontology library, along with supporting
documentation.  These ontologies may be copyrighted, but are published on the
internet for general discussion.

The SRKB list is open and unmoderated.  To subscribe, send mail to
with the following in the BODY of the message:
  subscribe srkb

Discussions sent to the SRKB mailing list are archived.
Archives of the SRKB mailing list (and related lists) are available in
hypertext form on the World Wide Web at

To post ontologies to the library, please contact me.

Tom Gruber <gruber@ksl.stanford.edu>