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From: dsn%umcp-cs.csnet@csnet-relay.arpa
Newsgroups: net.ai
Subject: expert system algorithms
Message-ID: <384@sri-arpa.UUCP>
Date: Tue, 27-Mar-84 14:45:44 EST
Article-I.D.: sri-arpa.384
Posted: Tue Mar 27 14:45:44 1984
Date-Received: Sun, 1-Apr-84 07:29:38 EST
Lines: 27

From:  Dana S. Nau <dsn%umcp-cs.csnet@csnet-relay.arpa>

        From: Toby Robison <eosp1!robison>

        I think it is hopeless to demand that the algorithms instanced by
        expert systems be well understood so they can be questioned.  Even
        when the algorithms can easily be printed, they will be hard for any
        human being to comprehend, except in the most trivial systems. ...

I disagree.  One of the reasons for separating an expert system's control
structure from the knowledge base is to allow for complex behavior with a
simple control algorithm.  For example, Mycin's control structure is only
about one typewritten page [1].  Jim Reggia and I at the Univ. of Maryland
are currently working on a considerably more complex expert system control
structure, but even it is not THAT hard to understand once one understands
the preliminary mathematical background [2].  We even have a proof of
correctness for the algorithm!

REFERENCES:

[1] Davis, Buchanan, and Shortliffe.  Production Rules as a Representation
for a Knowledge-Based Consultation Program.  ARTIFICIAL INTELLIGENCE 8
(1977), 15-45.

[2] Reggia, Nau, and Wang.  A Theory of Abductive Inference in Diagnostic
Expert Systems.  TR-1338, Computer Sci.  Dept., Univ.  of Maryland (Dec.
1983).  Submitted for Publication.