1,537 research outputs found
Incremental Parser Generation for Tree Adjoining Grammars
This paper describes the incremental generation of parse tables for the
LR-type parsing of Tree Adjoining Languages (TALs). The algorithm presented
handles modifications to the input grammar by updating the parser generated so
far. In this paper, a lazy generation of LR-type parsers for TALs is defined in
which parse tables are created by need while parsing. We then describe an
incremental parser generator for TALs which responds to modification of the
input grammar by updating parse tables built so far.Comment: 12 pages, 12 Postscript figures, uses fullname.st
An Efficient Probabilistic Context-Free Parsing Algorithm that Computes Prefix Probabilities
We describe an extension of Earley's parser for stochastic context-free
grammars that computes the following quantities given a stochastic context-free
grammar and an input string: a) probabilities of successive prefixes being
generated by the grammar; b) probabilities of substrings being generated by the
nonterminals, including the entire string being generated by the grammar; c)
most likely (Viterbi) parse of the string; d) posterior expected number of
applications of each grammar production, as required for reestimating rule
probabilities. (a) and (b) are computed incrementally in a single left-to-right
pass over the input. Our algorithm compares favorably to standard bottom-up
parsing methods for SCFGs in that it works efficiently on sparse grammars by
making use of Earley's top-down control structure. It can process any
context-free rule format without conversion to some normal form, and combines
computations for (a) through (d) in a single algorithm. Finally, the algorithm
has simple extensions for processing partially bracketed inputs, and for
finding partial parses and their likelihoods on ungrammatical inputs.Comment: 45 pages. Slightly shortened version to appear in Computational
Linguistics 2
A Transition-Based Directed Acyclic Graph Parser for UCCA
We present the first parser for UCCA, a cross-linguistically applicable
framework for semantic representation, which builds on extensive typological
work and supports rapid annotation. UCCA poses a challenge for existing parsing
techniques, as it exhibits reentrancy (resulting in DAG structures),
discontinuous structures and non-terminal nodes corresponding to complex
semantic units. To our knowledge, the conjunction of these formal properties is
not supported by any existing parser. Our transition-based parser, which uses a
novel transition set and features based on bidirectional LSTMs, has value not
just for UCCA parsing: its ability to handle more general graph structures can
inform the development of parsers for other semantic DAG structures, and in
languages that frequently use discontinuous structures.Comment: 16 pages; Accepted as long paper at ACL201
Research on Architectures for Integrated Speech/Language Systems in Verbmobil
The German joint research project Verbmobil (VM) aims at the development of a
speech to speech translation system. This paper reports on research done in our
group which belongs to Verbmobil's subproject on system architectures (TP15).
Our specific research areas are the construction of parsers for spontaneous
speech, investigations in the parallelization of parsing and to contribute to
the development of a flexible communication architecture with distributed
control.Comment: 6 pages, 2 Postscript figure
Arc-Standard Spinal Parsing with Stack-LSTMs
We present a neural transition-based parser for spinal trees, a dependency
representation of constituent trees. The parser uses Stack-LSTMs that compose
constituent nodes with dependency-based derivations. In experiments, we show
that this model adapts to different styles of dependency relations, but this
choice has little effect for predicting constituent structure, suggesting that
LSTMs induce useful states by themselves.Comment: IWPT 201
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