Compositions of extended top-down tree transducers
نویسندگان
چکیده
منابع مشابه
Compositions of Extended Top-down Tree Transducers
Unfortunately, the class of transformations computed by linear extended top-down tree transducers with regular look-ahead is not closed under composition. It is shown that the class of transformations computed by certain linear bimorphisms coincides with the previously mentioned class. Moreover, it is demonstrated that every linear epsilon-free extended top-down tree transducer with regular loo...
متن کاملInternship Report Compositions of Extended Top-down Tree Transducers
Many aspects of machine translation of natural languages can be formalized by employing weighted finite-state (string) transducers [22, 40]. Successful implementations based on this wordor phrasebased approach are, for example, the At&t Fsm toolkit [41], Xerox’s finite-state calculus [24], the Rwth toolkit [23], Carmel [19], and OpenFst [2]. However, the phrase-based approach is not expressive ...
متن کاملComposing extended top-down tree transducers
A composition procedure for linear and nondeleting extended top-down tree transducers is presented. It is demonstrated that the new procedure is more widely applicable than the existing methods. In general, the result of the composition is an extended top-down tree transducer that is no longer linear or nondeleting, but in a number of cases these properties can easily be recovered by a post-pro...
متن کاملCompositions of Top-down Tree Transducers with "-rules
Top-down tree transducers with "-rules ("tdtt) are a restricted version of extended top-down tree transducers. They are implemented in the framework Tiburon and ful ll some criteria desirable in a machine translation model. However, they compute a class of transformations that is not closed under composition (not even for linear and nondeleting "tdtt). A composition construction that composes "...
متن کاملThe Power of Extended Top-Down Tree Transducers
Extended top-down tree transducers (transducteurs g en eralis es descendants [Arnold, Dauchet: Bi-transductions de forêts. ICALP'76. Edinburgh University Press. 1976]) received renewed interest in the eld of Natural Language Processing. Here those transducers are extensively and systematically studied. Their main properties are identi ed and their relation to classical top-down tree transducers...
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ژورنال
عنوان ژورنال: Information and Computation
سال: 2008
ISSN: 0890-5401
DOI: 10.1016/j.ic.2008.03.019