Please use this identifier to cite or link to this item: doi:10.22028/D291-25877
Title: Parameterized type expansion in the feature structure formalism TDL
Author(s): Schäfer, Ulrich
Language: English
Year of Publication: 1995
SWD key words: Vererbung <Informatik>
Typ <Informatik>
Linguistische Datenverarbeitung
Konsistenz <Informatik>
Free key words: Computerlinguistik
Getypte Merkmalsstrukturen
computational linguistics
unifcation-based grammar formalism
typed feature structure
DDC notations: 004 Computer science, internet
Publikation type: Other
Abstract: Over the last few years, unification-based grammar formalisms have become the predominant paradigm in natural language processing systems because of their monotonicity, declarativeness, and reversibility. From the viewpoint of computer science, typed feature structures can be seen as data structures that allow representation of linguistic knowledge in a uniform fashion. Type expansion is an operation that makes the constraints on a typed feature structure explicit and determines their satisfiability. We describe an efficient expansion algorithm that takes care of recursive type definitions and allows exploration of different expansion strategies through the use of control knowledge. This knowledge is specified in a separate layer, independently of grammatical information. Memoization of the type expansion function drastically reduces the number of unifications. In the second part, nonmonotonic extensions to TDL and the implementation of well-typedness checks are presented. Both are closely related to the type expansion algorithm. The algorithms have been implemented in Common Lisp and are integrated parts of TDL and a large natural language dialog system.
Link to this record: urn:nbn:de:bsz:291-scidok-12324
Date of registration: 22-Aug-2007
Faculty: MI - Fakultät für Mathematik und Informatik
Department: MI - Informatik
Collections:SciDok - Der Wissenschaftsserver der Universität des Saarlandes

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