L. Karttunen. 1986. D-PATR: A development environment for unification-based grammars. Technical Report CSLI-86-61, SRI International and Center for the Study of Language and Information.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....M. Kaplan Xerox Palo Alto Research Center 1 Introduction A distinctive property of many current grammatical formalisms is their use of feature equality constraints to express a wide variety of grammatical dependencies. Lexical Functional Grammar[6] Head Driven Phrase Structure Grammar[14] PATR[8], FUG[12, 13] and the various forms of categorial unification grammar[9, 15, 16] all require an analysis of a sentence to satisfy a collection of feature constraints in addition to a set of conditions on the arrangement of words and phrases. Conjunctions of equality constraints can be quickly ....

Karttunen, L. (1986). D-PATR: A development environment for unification-based grammars. In Proceedings of COLING 1986, Bonn.

....to experimental results from [Wro87] all speed advantages of structure sharing are lost as a result of this overhead. An additional disadvantage of structure sharing is that it is harder to implement than incremental copying. Another approach to graph unification is reversible unification (e.g. [Kar86]) The basic idea of this approach to perform unification on nodes by annotating them, in a non destructive manner, along the way. If unification succeeds, a new node is created using the information that was associated with the node, after which the nodes are restored in their original state. If, ....

L. Karttunen. D-PATR: A development environment for unificationbased grammars. Technical Report CSLI-86-61, SRI International and Center for the Study of Language and Information, August 1986. 20

....to experimental results from [Wro87] all speed advantages of structure sharing are lost as a result of this overhead. An additional disadvantage of structure sharing is that it is harder to implement than incremental copying. Another approach to graph unification is reversible unification (e.g. [Kar86]) The basic idea of this approach to perform unification on nodes by annotating them, in a non destructive manner, along the way. If unification succeeds, a new node is created using the information that was associated with the node, after which the nodes are restored in their original state. If, ....

L. Karttunen. D-PATR: A development environment for unificationbased grammars. Technical Report CSLI-86-61, SRI International and Center for the Study of Language and Information, August 1986.

....that the application of admissibility conditions, e.g. LP statements and FCRs 1 , to a local tree t is prevented because particular feature values of categories in t are not yet specified, but they will be instantiated later somewhere else in the complete tree. Similar problems are described in [Karttunen 86] for D PATR. This work describes the latter problem and will present a solution working with computation, evaluation and propagation of constraints within local trees (depth 1) The constraint evaluation will reject local trees if the constraints of the subtrees of the daughters are violated. 1 ....

L. Karttunen, D-PATR: A Development Environment for Unification-Based Grammars, Proceedings 11th COLING, Bonn 1986

....substitution nodes; there is nothing corresponding to adjunction nodes. The CLE grammar can get al..ong without the adjunction operation, which is absolutely central to XTAG, because it has a powerful mechanism for handling long range dependencies based on the idea of gap threading (Pereira, 1981; Karttunen, 1986; Pulman, 1992) From the XTAG point of view, it is none the less hard to believe that substitution nodes on their own will be capable of modeling an equally broad range of complement structures. It does indeed appear to be the case that certain types of complements, particularly those related to ....

KARTTUNEN L. (1986). D-patr: A development environment for unification-based grammars. In Proceedings of the Eleventh International Conference on Computational Linguistics.

....allocating and deallocating copy node structures which is very important for the algorithm to be efficient. This holds, in particular, if it takes much more time to create new structures than to update old reclaimed structures. Comparison with other Approaches Karttunen s Reversible Unification [Karttunen 86] does not use structure sharing at all. A new DG is copied from the modified arguments after successful unification, and the argument DGs are then restored to their original state by undoing all the changes made during unification hence requiring a second pass through the DG to assemble the ....

....return(node) ENDIF ENDIF END unify Figure 4: The unification procedure approach methods early over redundant incr. lazy structure copying copying copying copying copying sharing naive yes yes yes no no no Pereira 85 no no no no no yes Karttunen Kay 85 no no yes no yes yes Karttunen 86 no no yes no no no Wroblewski 87 no yes yes yes no no Godden 90 no no yes no yes yes Kogure 90 no yes yes no yes yes LIC no yes no yes yes yes Figure 5: Comparison of unification approaches Both of these approaches suffer from difficulties of their own. In Godden s case, part of the copying is ....

Lauri Karttunen. D-PATR: A Development Environment for Unification-Based Grammars. Technical Report CSLI-86-61, Center for the Study of Language and Information, Stanford, August, 1986.

....White (1987) Two development environments have been constructed for formalisms related to generalised phrase structure grammars. One is called ProGram and is described by Evans (1985) the other is called GDE and is described by Briscoe et al. 1987) Boguraev et al. 1988) and Boguraev (1988) Karttunen (1986) describes D PATR, a development environment for PATR, which is a formalism suitable for encoding a wide variety of grammars, especially unification based grammars. A development environment called ud is described by Johnson and Rosner (1989) and implements a formalism related to PATR. The TFS ....

L. Karttunen. 1986. D-PATR: A development environment for unification-based grammars. In 11th International Conference on Computational Linguistics, 74--80. University of Bonn.

....element a string that does not occur as the upper string of any pair in 0. If some string occurs as the upper element of some pair in both Q and It, the priority union of and It only includes the pair in Q. Consequently .P. It in Figure 10 maps b to instead of The OPA R system at SlU (Karttunen [16]) had the same operation with a less respectable title. was called clobber . x y z w a b c Q.P.R= I I I x y w Figure 10. Example of priority union. The priority union operator .P. can be defined in terms of other regular expression operators in the Xerox calculus. A straightforward ....

Lauri Karttunen. 1986. D-PATR: A development environment for unification-based gramm .ars. In COLING'86, pages 74-80.

....string that does not occur as the upper string of any pair in Q. If some string occurs as the upper element of some pair in both Q and R, the priority union of Q and R only includes the pair in Q. Consequently Q .P. R in Figure 10 maps b to y instead of z. 3 The dpatr system at sri (Karttunen [16]) had the same operation with a less respectable title. It was called clobber . x a w c y b Q .P. R = x a y b , Q = z b w c , R = Figure 10. Example of priority union. The priority union operator .P. can be defined in terms of other regular expression operators in the ....

Lauri Karttunen. 1986. D-PATR: A development environment for unification-based grammars. In COLING'86, pages 74--80.

No context found.

L. Karttunen. 1986. D-PATR: A development environment for unification-based grammars. Technical Report CSLI-86-61, SRI International and Center for the Study of Language and Information.

No context found.

Karttunen, Lauri. 1986a. D-PATR: a development environment for unification- based grammars. Report No. CSLI-86--61. Center for the Study of Language and Information, Stanford University. Shortened version in Proceedings of Coling86 74--80.

No context found.

Lauri Karttunen. 1986. D-PATR: A development environment for unification-based grammars.

No context found.

Karttunen, Lauri. 1986a. D--PATR: a development environment for unification-- based grammars. Report No. CSLI--86--61. Center for the Study of Language and Information, Stanford University. Shortened version in Proceedings of Coling86 74--80.

Online articles have much greater impact   More about CiteSeer.IST   Add search form to your site   Submit documents   Feedback  

CiteSeer.IST - Copyright Penn State and NEC