Stanford Adaptive Networks Colloquium

[Mark Gluck]

         Stanford University Interdisciplinary Colloquium Series:
                 Adaptive Networks and their Applications

                     Nov. 22nd (Tuesday, 3:15pm) 

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	Toward a model of speech acquisition:  Supervised learning
	       and systems with excess degrees of freedom

                   MICHAEL JORDAN

                    E10-034C
                    Department of Brain and Cognitive Sciences
                    Massachussetts Institute of Technology
                    Cambridge, MA  02139
                       <jordan at psyche.mit.edu>

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                           Abstract

  The acquisition of speech production is an interesting domain for 
the development of connectionist learning methods.  In this talk, 
I will focus on a particular component of the speech learning problem, 
namely, that of finding an inverse of the function that relates 
articulatory events to perceptual events.  A problem for the learning 
of such an inverse is that the forward function is many-to-one and 
nonlinear.  That is, there are many possible target vectors corresponding 
to each perceptual input, but the average target is not in general a solution.  
I will argue that this problem is best resolved if targets are specified
implicitly with sets of constraints, rather than as particular vectors 
(as in direct inverse system identification).  Two classes of constraints 
are distinguished---paradigmatic constraints, which implicitly specify 
inverse images in articulatory space, and syntagmatic constraints, which 
define relationships between outputs produced at different points in 
time.  (The latter include smoothness constraints on articulatory 
representations, and distinctiveness constraints on perceptual 
representations).  I will discuss how the interactions between these 
classes of constraints may account for two kinds of variability in 
speech: coarticulation and historical change.

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Location: Room 380-380W, which can be reached through the lower level
 between the Psychology and Mathematical Sciences buildings. 

Technical Level: These talks will be technically oriented and are intended 
 for persons actively working in related areas. They are not intended
 for the newcomer seeking general introductory material. 

Information: To be added to the network mailing list, netmail to
             netlist at psych.stanford.edu For additional information,
             contact Mark Gluck (gluck at psych.stanford.edu).

Upcomming talks:
      Dec.  6:     Ralph Linsker (IBM) 

Co-Sponsored by: Departments of Electrical Engineering (B. Widrow) and
       Psychology (D. Rumelhart, M. Pavel, M. Gluck), Stanford Univ.