New Paper

[Joachim Diederich]

The following paper has been placed in the Neuroprose archives at
Ohio  State.   The  file  is "diederich.hybrid.ps.Z." See ftp in-
structions below.


         Efficient Question Answering in a Hybrid System

           Joachim Diederich (1,2) & Debra L. Long (2)

 (1) German National Research Center for Computer Science (GMD)
               Schloss Birlinghoven, P.O. Box 1240
                  D-5205 St.Augustin 1, Germany

                  (2) Department of Psychology
                 University of California, Davis
                     Davis, CA 95616, U.S.A.


ABSTRACT:

A connectionist model for answering open-class questions  in  the
context of text processing is presented. The system answers ques-
tions from different question categories, such  as  "How,"  Why,"
and  "Consequence" questions. These question categories have been
identified in several empirical studies (Graesser & Clark,  1985;
Graesser,  1990). The system responds to a question by generating
a set of possible answers that are weighted  according  to  their
plausibility.  Search is performed by means of a massively paral-
lel, directed spreading activation process.  The  search  process
operates  on  several knowledge sources (i.e., connectionist net-
works) that are learned or explicitly built-in. Spreading activa-
tion involves the use of signature messages (Lange & Dyer, 1989).
Signature  messages  are  numeric  values  that  are   propagated
throughout  the  networks  and  identify  a  particular  question
category (this makes the system hybrid). Binder units  that  gate
the flow of activation between textual units receive these signa-
tures and change their states. That is, the binder  units  either
block the spread of activation or allow the flow of activation in
a certain direction. The process results in a pattern of  activa-
tion  that  represents a set of candidate answers based on avail-
able knowledge sources.

This paper will appear in the IJCNN-91 Singapore Proceedings.


unix> ftp archive.cis.ohio-state.edu
Name: anonymous
Password: neuron
ftp> cd pub/neuroprose
ftp> binary
ftp> get diederich.hybrid.ps.Z
ftp> quit
unix> uncompress diederich.hybrid.ps.Z
unix> lpr diederich.hybrid.ps


Joachim Diederich
German National Research Center for Computer Science (GMD)
P.O. Box 1240
D-5205 St. Augustin 1
Germany