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From: voula@utcsri.UUCP (Voula Vanneli)
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Subject: Late Announcement-Artificial Intelligence Seminar at U of Toronto -             "Marker-passing during Problem Solving" J. Hendler, Brown Univ.
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Date: Wed, 10-Apr-85 08:57:46 EST
Article-I.D.: er, Brown Univ.
Posted: Wed Apr 10 08:57:46 1985
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                   UNIVERSITY OF TORONTO
               DEPARTMENT OF COMPUTER SCIENCE
         (GB = Galbraith Bldg., 35 St. George St.)

ARTIFICIAL INTELLIGENCE SEMINAR - Wednesday, April 10, 4 pm,
GB 244


                        Jim Hendler
        Dept. of Computer Science, Brown University

   Studies of Market Passing in Knowledge Representation
                and Problem Solving Systems.

                          Abstract

A standard problem in Artificial Intelligence  systems  that
do   planning  or  problem  solving  is  called  the  "late-
information, early-decision paradox." This occurs  when  the
planner makes a choice as to which action to consider, prior
to encountering information that could  either  identify  an
optimal  solution or that would present a contradiction.  As
the decision is made in the absence of this  information  it
is often the wrong one, leading to much needless processing.

In this talk I describe how the technique known as  "marker-
passing"  can  be used by a problem-solver.  Marker-passing,
which has been shown in the past to be useful for such  cog-
nitive  tasks as story comprehension and word sense disambi-
guation, is a parallel,  non-deductive,  "spreading  activa-
tion"  algorithm.   By combining this technique with a plan-
ning system the paradox described above can often be circum-
vented.   The marker-passer can also be used by the problem-
solver during "meta-rule" invocation and for finding certain
inherent  problems  in  plans.   An implementation of such a
system is discussed as are the  design  "desiderata"  for  a
marker-passer.