14.694, Diss: Computational Ling: Fouvry "Robust..."

LINGUIST List linguist at linguistlist.org
Tue Mar 11 16:01:32 UTC 2003

LINGUIST List:  Vol-14-694. Tue Mar 11 2003. ISSN: 1068-4875.

Subject: 14.694, Diss: Computational Ling: Fouvry "Robust..."

Moderators: Anthony Aristar, Wayne State U.<aristar at linguistlist.org>
            Helen Dry, Eastern Michigan U. <hdry at linguistlist.org>

Reviews (reviews at linguistlist.org):
	Simin Karimi, U. of Arizona
	Terence Langendoen, U. of Arizona

Home Page:  http://linguistlist.org/

The LINGUIST List is funded by Eastern Michigan University, Wayne
State University, and donations from subscribers and publishers.

Editor for this issue: Anita Yahui Huang <anita at linguistlist.org>

Please help us reach our total of $50,000 by making a donation at:


The LINGUIST List depends on the generous contributions from
subscribers like you; we would not be able to operate without your

The moderators, staff, and student editors at LINGUIST would like to
take this opportunity to thank you for your continuous support.

To post to LINGUIST, use our convenient web form at

Date:  Mon, 10 Mar 2003 12:02:35 +0000
From:  fouvry at coli.uni-sb.de
Subject:  Computational Ling: Fouvry "Robust Processing..."

-------------------------------- Message 1 -------------------------------

Date:  Mon, 10 Mar 2003 12:02:35 +0000
From:  fouvry at coli.uni-sb.de
Subject:  Computational Ling: Fouvry "Robust Processing..."

Institution: University of Essex
Program: Department of Language and Linguistics
Dissertation Status: Completed
Degree Date: 2003

Author: Frederik Fouvry

Dissertation Title:
Robust Processing for Constraint-based Grammar Formalisms

Linguistic Field: Computational Linguistics

Dissertation Director 1: Doug J Arnold

Dissertation Abstract:

This thesis addresses the issue of how Natural Language Processing
(NLP) systems using "constraint-based" grammar.  Formalisms can be
made "robust," i.e. able to deal with input which is in some way
ill-formed or extra-grammatical.  In NLP systems which use
constraint-based grammars the operation of "unification" typically
plays a central role.  Accordingly, the central concern of this thesis
is to propose an approach to "robust unification."

The first part of the thesis underlines the importance of robustness
in NLP, provides an overview of the sort of phenomena that require it,
and reviews the state of the art.  From this, it appears that no
methods currently exist for robust processing with grammars of any
real linguistic sophistication.

The class of constraint-based grammars studied here is that based on
Typed Feature Logic (TFL), of which Head-Driven Phrase Structure
Grammar is the instance chosen for exemplification.  The formalism is
described in the second part of the thesis.

Grammars based on TFL involve the notion of a "signature," which
defines the kinds of objects ("types") assumed to exist in the
grammar.  Processing typically involves combining information about
pieces of the input by unification.  From this perspective, the need
for robustness can be seen as arising because pieces of the input
provide information which is inconsistent with information from other
pieces of the input and/or from the grammar.  The first inconsistency
is tolerated --- it does not violate the grammar --- and processed
using "robust types" which are created by extending the signature to a
lattice.  Inconsistency with the grammar on the other hand is punished
by stripping away the offending information.  Weights, added to it on
the basis of the grammar, also disappear, thus making the
ungrammaticality measurable.  The conceptual and formal apparatus for
this is developed and exemplified in the third part of the

LINGUIST List: Vol-14-694

More information about the Linguist mailing list