M. C. Emele, `Unification with lazy non-redundant copying', Proc. ACL-91, 1991, pp. 323--330.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....form: the type symbol to be defined appears on the lefthand side of the equation. The right hand side is an expression of conjunctions and disjunctions of typed feature terms (Figure 1) Conjunctions are interpreted as meets on typed feature terms (implemented using a typed unification algorithm [Emele 91] The definition may have conditional constraints expressed as a logical conjunction of feature terms and introduced by : The righthand side feature term may contain the lefthand side type symbol in a subterm (or in the condition) thus defining a recursive type equation which gives the ....

Martin Emele. "Unification with lazy non- redundant copying". 29th Annual Meeting of the ACL, June 1991, Berkeley, CA.

....qb simplify he exphmation, the destrue;ire version of graph unification is used above. Other versions bed ou more efficient grapll uuilication methods such t Wroblewski s aud Kogurc s method[23, 16] have also been developed. 1,hrthermore, it is ey to modify other graph unificatiou nethods[21, 6] to allow augmented TFSs. 5 Conclusion This paper hs prol)ed au augmentation of fea ture structures (FSs) which introduces negative m formation into FSs m uuificatioud)sed tbrmalisms. U nificatiombmscd linguistic formalisurs use FSs to ticscribe linguis6c objects and phenomcua. liecause ginsOt ....

Martin Emele. Unification with lazy non-redundant copying. In Proceedings of the 9th Annual Meeting of the Association for Computational Linguistics, pages 3:25-330, AGL, University of California, Berkeley, California, USA, 1991.

.... 7 and 18 are inherited into the new structure of 20. This way virtual copies of the structures are produced, and these are unified. It is essential for efficiency that a virtual copy does not mean that the structure of the type has to be copied. The lazy copying ap proach ( Kogure, 1990] and [Emele, 1991] for lazy copying in TFS with historical backtracking) copies only overlapping parts of the structure. CFS avoids even this by structure and constraint sharing. For common sentences in German, which tend to be rather long, a lot of types will be generated. They supply only a small part of ....

M. C. Emele. Unification with lazy non-redundant copying. In Proceedings of the 9'th AC, Berkeley, 1991.

....would be inefficient because the number of feature structures would grow too fast as local ambiguities multiply out. More efficient algorithms for processing disjunctive feature constraints have been presented e.g. in [Kasper, 1987] Dorre and Eisele, 1990] Maxwell III and Kaplan, 1996] and [Emele, 1991]. Filtering constraints, on the other hand, can be processed with standard unification algorithms and a disjunctive normal form representation for feature structures if the feature values restricted by these constraints have limited depth and therefore limited compexity. The SUBCAT and SLASH ....

Emele, M. (1991). Unification with lazy non-redundant copying. In Proceedings of the 29th Annual Meeting of the Association for Computational Linguistics, pages 323--330, Berkeley.

....work of Emele and Zajac on typed unification grammars [9] is actually quite close to what we report here. Their work is an elaboration of [1] with the assumption that features are partial. Their main contribution has been the study of clever algorithms to carry out type unfolding efficiently. In [8], Martin Emele describes an implementation that shares many insights with the method that we describe here. In particular, he uses structure sharing to avoid much copying overhead, and whenever copying must be done, it is done such that no redundant copying is performed. However, his technique ....

Martin C. Emele. Unification with lazy non-redundant copying. In Proceedings of the 29th annual meeting of the ACL, Berkeley, California, June 1991. Association for Computational Linguistics.

....work of Emele and Zajac on typed unification grammars [16] is actually quite close to what we report here. Their work is an elaboration of [3] with the assumption that features are partial. Their main contribution has been the study of clever algorithms to carry out type unfolding efficiently. In [15], Martin Emele describes an implementation that shares many insights with the method that we describe here. In particular, he uses structure sharing to avoid much copying overhead, and whenever copying must be done, it is done such that no redundant copying is performed. However, his technique ....

Martin C. Emele. Unification with lazy non-redundant copying. In Proceedings of the 29th annual meeting of the ACL, Berkeley, California, June 1991. Association for Computational Linguistics.

....by avoiding to introduce choice points and waiting instead until the choice becomes deterministic. 5 Comparison to other approaches Recently some other systems employing typed feature formalisms and thus well suited to process HPSG have been developed. The TFS system (Emele and Zajac 1990, Emele 1991) is a LISP implementation of a typed feature unification formalism with inheritance. Types can be defined by formulas 8 The type list subsumes elist(the empty list) and nelist(the type of nonempty lists, with the appropriate attributes first and rest) comprising types, feature structures and ....

Emele, M. C. 1991. Unification with Lazy Non-Redundant Copying. In Proceedings of 29th Annual Meeting of the Association for Computational Linguistics, 323--330. Berkeley, CA.

....85 90 of the total parse time performing unification. There are essentially two main approaches: firstly, representing feature structures as skeletal DAGs and unification results as versions of them together with environments binding previously uninstantiated DAG nodes to values (Pereira, 1985; Emele, 1991); and secondly, destructively updating (sometimes incrementally constructed copies of) portions of input feature structures to produce the results (e.g. Karttunen, 1986; Wroblewski, 1987; Kogure, 1990; Tomabechi, 1991) The first approach often results in less copying of DAGs, though Pereira s ....

Emele, M. (1991) "Unification with lazy non-redundant copying." In Proceedings of the 29th Annual Meeting of the Association for Computational Linguistics, Berkeley, CA, 323--330.

....time and memory in two cases: when unification fails or when substructures of the input structures are not affected by the unification operation and could possibly be shared with the resultant structure. Some methods have been proposed to avoid redundant copying (e.g. Pereira 1985, Kogure 1990) Emele (1991) compares these and other approaches and proposes a method (Lazy Incremental Copying) combining advantages of these approaches and avoiding redundant copying (at least for conjunctive feature structures) Lazy Incremental Copying The key ideas of this method to avoid redundant copying are: to ....

Emele, M. C. (1991) Unification with Lazy Non-Redundant Copying. In Proceedings of 29th Annual Meeting of the Association for Computational Linguistics, 323--330. Berkeley, CA.

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M. C. Emele, `Unification with lazy non-redundant copying', Proc. ACL-91, 1991, pp. 323--330.

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Martin Emele. Unification with lazy non-redundant copying>>;. 29th Annual Meeting of the ACL, Berkeley, June 1991.

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Emele, M. C. (1991): Unification with Lazy Non--Redundant Copying. Linguistics. Berkeley.

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Martin Emele. 1991. "Unification with Lazy Non-Redundant Copying". In Proceedings of the 29th Annual Meeting of the ACL, 18-21 June 1991, Berkeley, CA. pp323-330.

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Martin Emele. 1991. Unification with lazy nonredundant copying. In Proceedings of the 29th Meeting of the Association for Computational Linguistics, pages 323--330, Berkeley, CA.

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Emele, M. C. (1991): Unification with Lazy Non--Redundant Copying. In: Proceedings of the 29th Annual Meeting of the Association for Computational Linguistics. Berkeley.

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Martin Emele. 1991. Unification with lazy nonredundant copying. In 29 th meeting Assoc.

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