Complexity of Dependencies at the Syntactic Level and at the Discourse Level

  • Date: 02/22/2007

Aravind Joshi (University of Pennsylvania )


Simon Fraser University


Aravind K. Joshi is, at present, the Henry Salvatori Professor of
Computer and Cognitive Science at the University of Pennsylvania. He
served as the Director of the Institute for Research in Cognitive
Science (IRCS) at the University of Pennsylvania from 1990 to 2001. His
honors include: Guggenheim Fellow, Fellow of IEEE, a Past President of
ACL, Fellow of ACM and Founding Fellow of the AAAI. He was awarded the
Research Excellence Award of the International Joint Conference on
Artificial Intelligence, IJCAI (1997) and an Honorary Degree from the
University of Paris in 2001. He is a member of the National Academy of
Engineering. In 2002, he was awarded the Lifetime Achievement Award by
ACL and in 2003, he won the David Rumelhart Award form the Cognitive
Science Society. In 2005, he was awarded the Benjamin Franklin Medal
for Cognitive Science by the Franklin Institute in Philadelphia.
Professor Joshi works in the areas of computational linguistics,
mathematical and processing models of language, artificial intelligence
and cognitive science.
Abstract: We will first discuss some issues (which have been
extensively investigated in recent years) concerning the complexity of
dependencies at the syntactic level. We will then present some data
about the types of dependencies that arise at the discourse level. This
work is based on the Penn Discourse Treebank (PDTB) which consists of
annotations of discourse connectives (explicit and implicit), their
arguments, their attributions and senses. We will compare these
dependencies to the ones we see at the syntactic level; raise some
issues; propose some conjectures concerning the relative complexities
at the syntactic and at the discourse level. This is joint work with
Alan Lee, Rashmi Prasad, Nikhil Dinesh (all from UPenn) and Bonnie
Webber (Edinburgh).