synchronous tree substitution grammar

... 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 ... paraphrasing. 3 The STSG 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 ... shieber}@seas.harvard.edu Abstract We describe our experiments with training algorithms for tree- to -tree synchronous tree- substitution grammar (STSG) for monolingual translation tasks such as sentence compression...

Ngày tải lên: 07/03/2014, 22:20

Ngày tải lên: 30/03/2014, 21:20

... 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 ... Jeopardy Model ? A Quasi- Synchronous Grammar for QA. In Proc. of EMNLP- CoNLL, pages 22–32. Elif Yamangil and Stuart M Shieber. 2010. Bayesian Synchronous Tree- Substitution Grammar Induction and ... 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...

Ngày tải lên: 19/02/2014, 19:20

... 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 ... 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 ... 2009. Bayesian Learning of a Tree Substitution Grammar. Association for Com- putational Linguistics. Matt Post. 2011. Judging Grammaticality with Tree Sub- stitution Grammar Derivations. Association...

Ngày tải lên: 07/03/2014, 18:20

Ngày tải lên: 08/03/2014, 06:20

Ngày tải lên: 17/03/2014, 00:20

Ngày tải lên: 17/03/2014, 00:20

Ngày tải lên: 17/03/2014, 02:20

Ngày tải lên: 17/03/2014, 02:20

Ngày tải lên: 23/03/2014, 16:20

Ngày tải lên: 23/03/2014, 16:20

Ngày tải lên: 31/03/2014, 20:20

... on a prob- abilistic synchronous dependency insertion grammar. Synchronous depend- ency insertion grammars are a version of synchronous grammars defined on de- pendency trees. We first introduce ... DIG can be viewed as a tree substitution grammar defined on depend- ency trees (as opposed to phrasal structure trees). The basic units of the grammar are elementary trees (ET), which are sub-sentential ... stochastic tree transducers and some versions of synchronous grammars pro- vide solutions for the non-isomorphic tree based transduction problem and hence possible solutions for MT. Synchronous Tree...

Ngày tải lên: 20/02/2014, 15:20

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...

Ngày tải lên: 20/02/2014, 18:20

... 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- abes ... (predicate-argument) constraints. Elementary trees are of two kinds - (a) INITIAL TREES and (b) AUX- ILIARY TREES. Nodes on the frontier of initial trees are marked as substitution sites by a '~'. ... 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...

Ngày tải lên: 20/02/2014, 22:20

... 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...

Ngày tải lên: 21/02/2014, 20:20

... produces a tree description. We still need to solve this de- scription in order to obtain trees (i.e. the items of the resulting grammar) . Constraint-based tree description solver The tree description ... and Duchier, 2004). At the end of this tree description solving pro- cess we obtain the trees of the grammar. Note that the use of constraint programming techniques to solve tree descriptions allows us ... contain- ing more than 6.000 trees. This grammar has been evaluated on the TSNLP test-suite, with a cover- age rate of 75 % (see (Crabb´e, 2005)). The meta- grammar used to produce that grammar consists...

Ngày tải lên: 22/02/2014, 02:20

... 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...

Ngày tải lên: 22/02/2014, 10:20

... elementary trees of TAG, allows us to "lexicalize" a TAG gram- mar: we can associate each tree in a grammar with a lexical item [Schabes et al 1988, Schabes 1990] 4. The tree will ... respect to the nodes of an elementary tree; it is impossible to relate nodes in dif- ferent trees. When an auxiliary tree fl is adjoined into an initial tree et, the nodes of fl are not ordered ... 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...

Ngày tải lên: 22/02/2014, 10:20