representation of input text in a conversation

[Jim Davies]

ACT-R users:

        I am trying to make a model of an orangutan that can use sign
language. The eventual goal is to have a real time orangutan simulation
that people can talk to. The model will respond like the orangutan.
Hopefully the system will simulate simple conversations.
        So what I need is a way to input user's text. There will be a
seperate, non-ACT speech recognition module that will be feeding the ACT-R
model text. So the input must be in the form of a chunk, maybe a goal:

        (goal-one
            word1   how
            word2   are
            word3   you
            answer  nil)

and then the goal would pop when an answer is found. This is similar to
the addtion examples:

        (goal-two
            arg1     one
            arg2     eight
            operator plus       
            answer   nil)       

This is not satisfying for a few reasons. One is that the number of words
in the input sentence is variable, and its inelegant to have a "word1,
word2, .... , wordN" for the number of possible words in the sentence.
Also, for whatever N might be, the system would not take a sentence with
n+1 words. Also, there would usually be lots of 'nil's in word slots.
        So I thought about it a bit and came up with the idea of a linked
list to represent the sentence, like the number line is represented in
some ACT models. Following is a representation of the utterance "Who are
you":

(goal-three
     sentence s1
     response nil)

(s1
     word     who
     last     nil
     next     s2)

(s2
     word     are 
     last     s1                
     next     s3)

(s3  
     word     you
     last     s2
     next     nil)

Then the idea is that a goal would be set to determine if the utterance is
a statement, question, or command, and push subgoals from there. 

I welcome any thoughts about this representation, both psychological and
technical.

For more information about this project, see:
http://www.cc.gatech.edu/gvu/perception/projects/primatech/

JimDavies  jimmyd at cc.gatech.edu              home: 404-223-1366
           http://www.cc.gatech.edu/~jimmyd/