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Integrating World Knowledge with Cognitive Parsing
The work presented in this article builds on the account of cognitive parsing given by the SOUL system (Konieczny & Strube, 1995), an object-oriented implementation of Parameterized Head Attachment (Konieczny et al, 1991) based on Head-Driven Phrase-Structure Grammar (Pollard & Sag, 1994). We describe how the initial semantic representation proposed by the parser is translated into a logical form suitable for inference, thus making it possible to integrate world knowledge with cognitive parsing. As a semantic and knowledge representation system we use the most expressive implemented logic for natural language understanding. Episodic Logic (Hwang & Schubert, 1993), and its computational implementation, Epilog (Schaeffer et al, 1991)
A Sign-Based Phrase Structure Grammar for Turkish
This study analyses Turkish syntax from an informational point of view. Sign
based linguistic representation and principles of HPSG (Head-driven Phrase
Structure Grammar) theory are adapted to Turkish. The basic informational
elements are nested and inherently sorted feature structures called signs.
In the implementation, logic programming tool ALE (Attribute Logic Engine)
which is primarily designed for implementing HPSG grammars is used. A type and
structure hierarchy of Turkish language is designed. Syntactic phenomena such a
s subcategorization, relative clauses, constituent order variation, adjuncts,
nomina l predicates and complement-modifier relations in Turkish are analyzed.
A parser is designed and implemented in ALE.Comment: MS. Thesis, Dept. of Computer Engineering, Middle East Technical
University, Ankara January, 1996, 97 pages. 5 eps figures, uses
avm,psfig,lingmacros,tree-dvips,ulem,QobiTree,alltt
ulem.sty,QobiTree.sty,alltt.sty and eps files included in ta
Amalia -- A Unified Platform for Parsing and Generation
Contemporary linguistic theories (in particular, HPSG) are declarative in
nature: they specify constraints on permissible structures, not how such
structures are to be computed. Grammars designed under such theories are,
therefore, suitable for both parsing and generation. However, practical
implementations of such theories don't usually support bidirectional processing
of grammars. We present a grammar development system that includes a compiler
of grammars (for parsing and generation) to abstract machine instructions, and
an interpreter for the abstract machine language. The generation compiler
inverts input grammars (designed for parsing) to a form more suitable for
generation. The compiled grammars are then executed by the interpreter using
one control strategy, regardless of whether the grammar is the original or the
inverted version. We thus obtain a unified, efficient platform for developing
reversible grammars.Comment: 8 pages postscrip
An Abstract Machine for Unification Grammars
This work describes the design and implementation of an abstract machine,
Amalia, for the linguistic formalism ALE, which is based on typed feature
structures. This formalism is one of the most widely accepted in computational
linguistics and has been used for designing grammars in various linguistic
theories, most notably HPSG. Amalia is composed of data structures and a set of
instructions, augmented by a compiler from the grammatical formalism to the
abstract instructions, and a (portable) interpreter of the abstract
instructions. The effect of each instruction is defined using a low-level
language that can be executed on ordinary hardware.
The advantages of the abstract machine approach are twofold. From a
theoretical point of view, the abstract machine gives a well-defined
operational semantics to the grammatical formalism. This ensures that grammars
specified using our system are endowed with well defined meaning. It enables,
for example, to formally verify the correctness of a compiler for HPSG, given
an independent definition. From a practical point of view, Amalia is the first
system that employs a direct compilation scheme for unification grammars that
are based on typed feature structures. The use of amalia results in a much
improved performance over existing systems.
In order to test the machine on a realistic application, we have developed a
small-scale, HPSG-based grammar for a fragment of the Hebrew language, using
Amalia as the development platform. This is the first application of HPSG to a
Semitic language.Comment: Doctoral Thesis, 96 pages, many postscript figures, uses pstricks,
pst-node, psfig, fullname and a macros fil
Robust Grammatical Analysis for Spoken Dialogue Systems
We argue that grammatical analysis is a viable alternative to concept
spotting for processing spoken input in a practical spoken dialogue system. We
discuss the structure of the grammar, and a model for robust parsing which
combines linguistic sources of information and statistical sources of
information. We discuss test results suggesting that grammatical processing
allows fast and accurate processing of spoken input.Comment: Accepted for JNL
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