probabilistic tree adjoining grammars
Tài liệu Báo cáo khoa học: "Prefix Probabilities from Stochastic Tree Adjoining Grammars*" pptx
Ngày tải lên :
20/02/2014, 18:20
...
trees
and .A is a set of auxiliary trees. Trees in :TU.A
are also called elementary trees.
We refer to the root of an elementary tree t as
Rt.
Each auxiliary tree has exactly one distin-
guished ... context-free grammars.
Computational Linguis-
tics,
17(3):315-323.
A. K. Joshi and Y. Schabes. 1992. Tree- adjoining gram-
mars and lexicalized grammars. In M. Nivat and
A. Podelski, editors,
Tree ... auxiliary trees with
empty yield
case of lexicalized TAGs. However, in the com-
putation of the prefix probability we must take
into account trees with non-empty yield which
behave like trees...
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Tài liệu Báo cáo khoa học: "Some Novel Applications of Explanation-Based Learning to Parsing Lexicalized Tree-Adjoining Grammars"" doc
Ngày tải lên :
20/02/2014, 22:20
... approach to other lexicalized grammars. In
Section 8 we conclude with some directions for future
work.
2
Lexicalized Tree- Adjoining
Grammar
Lexicalized Tree- Adjoining Grammar (LTAG) (Sch- ... training corpus.
Auxiliary trees in LTAG represent recursive struc-
tures. So if there is an auxiliary tree that is used in
an LTAG parse, then that tree with the trees for
its arguments can ... (l~niladdp~Ja] (2.2) ~ Pbl~ael:
(b) (c)
Figure 2: (as and/~s) Elementary trees, (a) Derived Tree, (b) Derivation Tree, and (c) Dependency tree for
the sentence:
show me the flights from Boston to Philadelphia....
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Tài liệu Báo cáo khoa học: "Long-Distance Scrambling and Tree Adjoining Grammars" doc
Ngày tải lên :
22/02/2014, 10:20
... abbreviatory device for listing a finite set of
elementary trees), since it is impossible to adjoin one
tree into another tree of the same tree set. There are
several other syntactic issues which ... University Linguis-
tics Club.
[Joshi 1987a] Joshi, Aravind K., 1987. An Introduction
to Tree Adjoining Grammars. In Manaster-Ramer, A.
(editor), Mathematics of Language. John Benjamins,
Amsterdam. ... Scrambling and Tree Adjoining Gram-
mars. Unpublished Paper, University of Pennsylvania.
[Schabes 1990] Schabes, Yves, August 1990. Mathemati-
cal and Computational Aspects of Lezicalized Grammars. ...
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Tài liệu Báo cáo khoa học: "BIDIRECTIONAL PARSING OF LEXICALIZED TREE ADJOINING GRAMMARS" pdf
Ngày tải lên :
22/02/2014, 10:20
... of trees, called
initial trees
and
auxiliary trees
respectively. The trees in the set
IuA are
called
elementary trees.
We assume that the reader is familiar with the
definitions of adjoining ... to the Production of
O(n 6)
Earley Parsers for Tree Adjoining Grammars. In
Proceedings of the 1st International Workshop on
Tree Adjoining Grammars.
Dagstuhl Castle, F.R.G
Satta, Giorgio, ...
Lexicalized Tree Adjoining Grammars
(Schabes
et
al.,
1988) are a refinement of TAGs such that each
elementary tree is associated with a lexieal item,
called the
anchor
of the tree. Therefore,...
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Báo cáo khoa học: "Strong Lexicalization of Tree Adjoining Grammars" docx
Ngày tải lên :
07/03/2014, 18:20
... only increases by 1. Thus, simple
context-free tree grammars strongly lexicalize
tree adjoining grammars and themselves.
1 Introduction
Tree adjoining grammars [TAG] (Joshi et al., 1969;
Joshi et ... grammars.
In Proc. 8th Int. Workshop Tree Adjoining Grammars
and Related Formalisms, pages 121–126. ACL.
Marco Kuhlmann and Giorgio Satta. 2012. Tree-
adjoining grammars are not closed under strong ... it was shown (KUHLMANN, SATTA:
Tree- adjoining grammars are not closed un-
der strong lexicalization. Comput. Linguist.,
2012) that finitely ambiguous tree adjoining
grammars cannot be transformed...
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Báo cáo khoa học: "A Tree Transducer Model for Synchronous Tree-Adjoining Grammars" pdf
Ngày tải lên :
17/03/2014, 00:20
... assumptions on all tree- adjoining grammars
(and synchronous tree- adjoining grammars) . A
tree- adjoining grammar (TAG) is a finite set of
initial trees and a finite set of auxiliary trees. Our
1070
Jonathan ... synchronous tree- adjoining grammars
(STAGs) in terms of tree transducers (or
equivalently, synchronous tree substitution
grammars) is developed. Essentially, a
STAG corresponds to an extended tree
transducer ... M. Shieber. 2004. Synchronous grammars as
tree transducers. In Proc. TAG+7, pages 88–95.
Stuart M. Shieber. 2006. Unifying synchronous tree
adjoining grammars and tree transducers via bimor-
phisms....
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Báo cáo khoa học: "Parsing preferences with Lexicalized Tree Adjoining Grammars : exploiting the derivation tree" pptx
Ngày tải lên :
17/03/2014, 07:20
... derivation trees :
1. Prefer the derivation tree with the fewer
number of nodes
2. Prefer to attach an m -tree low 6
3. Prefer the derivation tree with the fewer
number of 13 -tree nodes
Principle ...
or initial 2. A tree has at most 1 foot-node, such a
tree is an auxiliary tree. Trees that are not
auxiliary are initial. Elementary trees combine
with 2 operations : substitution and
adjunetion. ... same derived tree can be
obtained using different derivations. This is why
parsing LTAGs yields a derivation tree, from
2 Traditionally initial trees are called o~, and
auxiliary trees 13
585...
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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 ... 2009;
Cohn et al., 2010) employs a probabilistic model of
a TSG and predicts derivations from observed parse
trees in an unsupervised way.
A Probabilistic Tree Substitution Grammar
(PTSG) assigns ... with other elementary trees.
A derivation is a process of forming a parse tree.
It starts with a root symbol and rewrites (substi-
tutes) nonterminal symbols with elementary trees
until there are...
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Tài liệu Báo cáo khoa học: "An Alternative Conception of Tree-Adjoining Derivation*" ppt
Ngày tải lên :
20/02/2014, 21:20
... str!ng, the
derived tree
structure of the string.
The formalism of tree- adjoining grammars (TAG),
on the other hand, decouples these two notions of
derivation tree and derived tree. Intuitively, ... a predicative tree and a modifier
tree are adjoined at a single node, then the pred-
icative tree attaches "higher" than the modifier
tree; in terms of the derived tree, it is as ... lexicalized tree-
adjoining grammars. To appear in Proceedings
of the 14 th International Conference on Com-
putational Linguistics.
Stuart M. Shieber and Yves Schabes. 1990. Syn-
chronous tree- adjoining...
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