[PDF] Top 20 Inducing Tree-Substitution Grammars

... The MPD and MPT parsing algorithms require the computation of Monte-Carlo integrals over the large space of possible derivations or trees. Consequently, unless the distribution is extremely peaked the chance of sampling ... See full document

... In the previous chapter we described and compared various STSG models. In this section we will focus on a subclass of Lexicalized Tree Substitution Gram- mars, which considers elementary trees with exactly ... See full document

... in tree substitution grammar (TSG) as an alter- native to CFG for modeling syntax trees (Post and Gildea, 2009; Tenenbaum et ...large tree fragments. These tree frag- ments have great ... See full document

... When looking at the extracted fragments we ask if we could have predicted which fragments occur twice or more. Figure 3 attempts to tackle this ques- tion by reporting some statistics on the extracted fragments. The ... See full document

... off-the-shelf parser and pattern match the fragments in our grammar against the tree. With enough pos- itive and negative training data (in the form of au- tomatic parses of good and bad sentences), we can ... See full document

... for inducing depen- dency grammars, however the models em- ployed are overly simplistic, particularly in comparison to supervised parsing ...using tree substi- tution grammar which is capable of ... See full document

... such grammars (exponential in the size of the training data) forces either implicit representations (Goodman, 1996; Bansal and Klein, 2010) — which do not permit arbitrary probability distributions over the ... See full document

... In our formulation of STAGs we use states (cf. F¨ul¨op et al. (2010) for the use of states in STSGs). The states make intersection with de- vices of finite-state power possible. More specif- ically, they allow for a ... See full document

... for tree trans- formations, however they are not suitably ex- pressive for all applications in machine transla- tion (Shieber, ...all tree trans- formations of XTT have a certain locality condi- tion, which ... See full document

... dependency grammars allow considerable freedom in how to analyze specific constructions such as verb clusters (which verb is the head?) prepositional phrases and particles (is the head the noun or the ... See full document

... Finally, to simulate the scenario where the model has access to a dependency tree given by an ex- ternal parser we report results with hard attention. Forcing the model to make hard decisions during training ... See full document

... lexicalized grammars for modeling idiosyncratic constructions in French was identified by Abeillé (1988) and Abeillé and Sch- abes ...small Tree Adjoining Grammar (TAG) of 1,200 elemen- tary trees and 4,000 ... See full document

... Because PCFGs are, as their name sug- gests, context-free, they cannot encode many dependencies that occur in natural language, such as the dependencies be- tween determiners and nouns, allowing them to overgenerate ... See full document

... Context-free grammars (CFGs) are a useful tool for describing the structure of language, modeling a va- riety of linguistic phenomena while still permitting efficient ...in grammars that are overly ...of ... See full document

... Synchronous tree substitution grammars are a translation model that is used in syntax-based machine ...bottom-up tree trans- ducer, which is the bottom-up analogue with one essential ... See full document

... weighted tree transformation, that assigns a weight to each pair of input and output trees, where both the input and output tree may not con- tain any ...connected tree pair (ξ, ζ), we can apply the ... See full document

... In this paper, we describe a formalism based on tree descriptions called d-tree substitution grammars DSG.. 5 The elementary tree descriptions in DSG can be used to describe lexical item[r] ... See full document

... a tree, P (t | e) is either equal to 1 (when t and e are consistent) or 0 ...full tree must be segmented into one or more elementary ...elementary tree e with root non-terminal symbol c ... See full document

... auxiliary tree includes a special nonterminal leaf node labeled with the same sym- bol as the root ...of substitution and insertion operators are identical with those of TIG and ... See full document

... We have demonstrated how our grammar trans- formation can implicitly represent an exponential space of tree fragments efficiently, allowing us to build a sampler with considerably better mix- ing properties than a ... See full document