tree substitution grammar derivations
Báo cáo khoa học: "Bayesian Synchronous Tree-Substitution Grammar Induction and its Application to Sentence Compression" pdf
Ngày tải lên :
07/03/2014, 22:20
... syn-
chronous tree- substitution (Eisner, 2003) or tree-
adjoining grammars may better capture the pair-
ings.
In this work, we explore techniques for inducing
synchronous tree- substitution grammars ... Model
Synchronous tree- substitution grammar is a for-
malism for synchronously generating a pair of
non-isomorphic source and target trees (Eisner,
2003). Every grammar rule is a pair of elemen-
tary trees ... Learning an STSG from aligned
trees is tantamount to determining a segmentation
of the trees into elementary trees of the grammar
along with an alignment of the elementary trees
(see Figure 1 for an...
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Tài liệu Báo cáo khoa học: "Bayesian Symbol-Refined Tree Substitution Grammars for Syntactic Parsing" pptx
Ngày tải lên :
19/02/2014, 19:20
... symbol refinement without heuristics.
3 Symbol-Refined Tree Substitution
Grammars
In this section, we propose Symbol-Refined Tree
Substitution Grammars (SR-TSGs) for syntactic
parsing. Our SR-TSG ... Tree Substitution Grammar
(PTSG) assigns a probability to each rule in the
grammar. The probability of a derivation is defined
as the product of the probabilities of its component
elementary trees ... Accurate
Parsing with an All-Fragments Grammar. In In Proc.
of ACL, pages 1098–1107.
Phil Blunsom and Trevor Cohn. 2010. Unsupervised
Induction of Tree Substitution Grammars for Depen-
dency Parsing....
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Tài liệu Báo cáo khoa học: "TREE UNIFICATION GRAMMAR" pptx
Ngày tải lên :
21/02/2014, 20:20
... easily and transparently.
Tree adjoining grammars (TAGs) (Joshi, Levy and Takahashi,
1975, Vijay-Shanker and Joshi, 1988) possess trees as basic
grammar structures, and grammar rules are used ... tree with that of the tree into which
it is adjoined. In this way, a more complete description of the
final tree is gradually constructed. However, in FTAG tree
descriptions the internal tree ... specified trees in order to obtain more complex fully
specified trees. In TUG, partially specified trees are combined
(not modified) in order to ohtain a more fully specified complex
tree. Feature...
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Tài liệu Báo cáo khoa học: "STRING-TREE CORRESPONDENCE GRAMMAR: A DECLARATIVE GRAMMAR FORMALISM FOR DEFINING THE CORRESPONDENCE BETWEEN STRINGS OF TERMS AND TREE STRUCTURES" pdf
Ngày tải lên :
22/02/2014, 10:20
... elements of the set of subtrees
of the tree : such a relation is called a string-
tree correspondence. An example of a string -tree
correspondence is given in fig. I.
TREE: NP
I [
4 NP
2 :AP ... of grammar rules applied (as in derivation
trees). The inclusion of the substring-subtree
correspondence is also another characteristic of
the grammar formalism. One also sees that the
grammar ... STRING -TREE CORRESPONDENCE GRAMMAR: A DECLARATIVE GRAMMAR FORMALISM FOR DEFINING
THE CORRESPONDENCE BETWEEN STRINGS OF TERMS AND TREE STRUCTURES
YUSOFF ZAHARIN
Groupe...
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Tài liệu Báo cáo khoa học: "The Use of Shared Forests in Tree Adjoining Grammar Parsing" pptx
Ngày tải lên :
22/02/2014, 10:20
... auxiliary tree is called the spine
of the auxiliary tree. An elementary tree is either
an initial tree or an auxiliary tree. We use a to refer
to initial trees and/3 for auxiliary trees.
A ... inputs.
5 Derivation versus Derived Trees in
TAG
For grammar formalisms involving the derivation of
trees, a tree is called a derived tree with respect to a
given grammar if it can be derived using ... rules of the grammar. A derivation tree of the
grammar, on the other hand, is a tree that encodes
the sequence of rewritings used in deriving a derived
tree. In the case of cfg, a tree that is...
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Báo cáo khoa học: "Native Language Detection with Tree Substitution Grammars" pptx
Ngày tải lên :
07/03/2014, 18:20
... Inducing Compact but Accurate Tree-
Substitution Grammars. In Proceedings NAACL.
Trevor Cohn, and Phil Blunsom 2010. Blocked inference
in Bayesian tree substitution grammars. Association
for Computational ... Bayesian Learning
of a Tree Substitution Grammar. Association for Com-
putational Linguistics.
Matt Post. 2011. Judging Grammaticality with Tree Sub-
stitution Grammar Derivations. Association ... with Tree Substitution Grammars
Ben Swanson
Brown University
chonger@cs.brown.edu
Eugene Charniak
Brown University
ec@cs.brown.edu
Abstract
We investigate the potential of Tree Substitu-
tion Grammars...
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Báo cáo khoa học: "A Compacting the Penn Tree bank Grammar" doc
Ngày tải lên :
08/03/2014, 05:21
...
Abstract
Treebanks, such as the Penn Treebank (PTB),
offer a simple approach to obtaining a broad
coverage grammar: one can simply read the
grammar off the parse trees in the treebank.
While ...
(4)
ii. NP (5)
DT NN CC DT NN
4 Grammar Compaction
The idea of partiality of structure in treebanks
and their grammars suggests a route by which
treebank grammars may be reduced in size, ... defined) are elimin-
ated from the grammar.
Our experiments on compacting a PTB tree-
1 For the complete investigation of the grammar ex-
tracted
from the
Penn Treebank II see (Gaizauskas,
1995)...
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Báo cáo khoa học: "Preserving Semantic Dependencies in Synchronous Tree Adjoining Grammar*" doc
Ngày tải lên :
08/03/2014, 06:20
... capability of synchronous tree adjoin-
ing grammars. Computational Intelligence, 10(4).
K. Vijay-Shanker and D.J. Weir. 1993. The use of
shared forests in tree adjoining grammar parsing.
In Proceedings ... each substitution of initial tree a¢
with predicate variable w into "),¢ at node
address U, emit (¢,
arg(v ,
r/), w)
• For each modifier adjunction of auxil-
iary tree/ 3¢ into tree ... target derivations, where each
predicate node in the source dependency graph
is linked to a set of possible elementary trees in
the target grammar, each of which is instanti-
ated with substitution...
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Báo cáo khoa học: "Sentence Planning as Description Using Tree Adjoining Grammar " pptx
Ngày tải lên :
08/03/2014, 21:20
... operations to produce
derived trees recognized by the grammar. In substitu-
tion, the root of the first tree is identified with a leaf of the
second tree, called the substitution site. Adjoining ... operation, where the first tree
replaces the subtree of the second tree rooted at a node
called the adjunction site; that subtree is then substituted
back into the first tree at a distinguished ... node. Elementary trees without foot nodes are
called INITIAL trees and can only substitute; trees with
foot nodes are called AUXILIARY trees, and must adjoin.
(The symbol $ marks substitution...
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Báo cáo khoa học: "Blocked Inference in Bayesian Tree Substitution Grammars" potx
Ngày tải lên :
17/03/2014, 00:20
... Oxford
Phil.Blunsom@comlab.ox.ac.uk
Abstract
Learning a tree substitution grammar is
very challenging due to derivational am-
biguity. Our recent approach used a
Bayesian non-parametric model to induce
good derivations from treebanked input
(Cohn ... improve parsing accuracy.
1 Introduction
Tree Substitution Grammar (TSG) is a compelling
grammar formalism which allows nonterminal
rewrites in the form of trees, thereby enabling
the modelling ... supervised scenario where treebanked data is
available. This is because treebanks are typically
not annotated with their TSG derivations (how to
decompose a tree into elementary tree fragments);
instead...
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Tài liệu Báo cáo khoa học: "Generating with a Grammar Based on Tree Descriptions: a Constraint-Based Approach" pptx
Ngày tải lên :
20/02/2014, 18:20
... Description Grammars
There is a range of grammar formalisms which
depart from Tree Adjoining Grammar (TAG) by
taking as basic building blocks tree descriptions
rather than trees. D -Tree Grammar (DTG) ... Sentence planning
as description using Tree- Adjoining Grammar. In
Proceedings of ACL ’97.
K. Vijay-Shanker. 1992. Using descriptions of trees
in Tree Adjoining Grammars. Computational Lin-
guistics, ... relevance of Tree Adjoining
Grammar to generation. In Natural Language Gen-
eration, chapter 16. Martinus Jijhoff Publishers,
Dordrecht, Holland.
L. Kallmeyer. 1999. Tree Description Grammars and
Underspecified...
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