Memoization in Constraint Logic Programming

This paper shows how to apply memoization (caching of subgoals and associated answer substitutions) in a constraint logic programming setting. The research is is motivated by the desire to apply constraint logic programming (CLP) to problems in natural language processing that involve (constraint) interleaving or coroutining, such as GB and HPSG parsing.Comment: 11 page

ONTOGENERATION: Reusing Domain and Linguistic Ontologies for Spanish Text Generation

A significant problem facing the reuse of ontologies is to make their content more widely accessible to any potential user. Wording all the information represented in an ontology is the best way to ease the retrieval and understanding of its contents. This article proposes a general approach to reuse domain and linguistic ontologies with natural language generation technology, describing a practical system for the generation of Spanish texts in the domain of chemical substances. For this purpose the following steps have been taken: (a) an ontology in the chemicals domain developed under the METHONTOLOGY framework and the Ontology Design Environment (ODE) has been taken as knowledge source; (b) the linguistic ontology GUM (Generalized Upper Model) used in other languages has been extended and modified for Spanish; (c) a Spanish grammar has been built following the systemic-functional model by using the KPML (Komet-Penman Multilingual) environment. As result, the final system named Ontogeneration permits the user to consult and retrieve all the information of the ontology in Spanish

Classification and representation of types in TDL

TDL is a typed feature-based representation language and inference system, specifically designed to support highly lexicalized constraint-based grammar theories. Type definitions in TDL consist of type and feature constraints over the full Boolean connectives together with coreferences, thus making TDL Turing-complete. TDL provides open- and closed-world reasoning over types. Working with partially as well as with fully expanded types is possible. Efficient reasoning in TDL is accomplished through specialized modules. In this paper, we will highlight the type/inheritance hierarchy module of TDL and show how we represent conjunctively and disjunctively defined types. Negated types and incompatible types are handled by specialized bottom symbols. Redefining a type only leads to the redefinition of the dependent types, and not to the redefinition of the whole grammar/lexicon. Undefined types are nothing special. Reasoning over the type hierarchy is partially realized by a bit vector encoding of types, similar to the one used in Aït-Kaci\u27s LOGIN. However, the underlying semantics does not harmonize with the open-world assumption of TDL. Thus, we have to generalize the GLB/LUB operation to account for this fact. The system, as presented in the paper, has been fully implemented in Common Lisp and is an integrated part of a large NL system. It has been installed and successfully employed at other sites and runs on various platforms

Verzeichnis von Softwarekomponenten für natürlichsprachliche Systeme : Ergebnisse einer Umfrage im Rahmen der VERBMOBIL-Vorbereitung

Das DFKI (Deutsches Forschungszentrum für Künstliche Intelligenz) wurde vom BMFT (Bundesministerium für Forschung und Technologie) mit der Durchführung einer Umfrage zu existierenden Software-Komponenten im Bereich Verarbeitung natürlicher Sprache beauftragt (413 - 4001 - 01 IV 201). Das Ziel der Umfrage war die Erstellung einer Übersicht von in Deutschland verfügbaren Software-Komponenten, die im Bereich der natürlichsprachlichen Systeme für das Projekt VERBMOBIL relevant sein könnten. Das Ergebnis dieser Umfrage liegt nun vor. Zur Durchführung der Umfrage wurde ein Fragebogen erstellt, der im März 1992 über die News-Gruppe mod-ki verbreitet und außerdem an ca. 400 Adressen geschickt wurde (Mitglieder der Gesellschaft für Informatik e. V. FA 1.3 1 "Natürliche Sprache", Mitglieder der DGfS, Sektion Computerlinguistik). Das Verzeichnis ist auf in Deutschland entwickelte Software beschränkt und enthält akademische, kommerzielle und geschützte Software, wobei jeweils angegeben ist, unter welchen Bedingungen die Komponenten erhältlich sind

Constraint Logic Programming for Natural Language Processing

This paper proposes an evaluation of the adequacy of the constraint logic programming paradigm for natural language processing. Theoretical aspects of this question have been discussed in several works. We adopt here a pragmatic point of view and our argumentation relies on concrete solutions. Using actual contraints (in the CLP sense) is neither easy nor direct. However, CLP can improve parsing techniques in several aspects such as concision, control, efficiency or direct representation of linguistic formalism. This discussion is illustrated by several examples and the presentation of an HPSG parser.Comment: 15 pages, uuencoded and compressed postscript to appear in Proceedings of the 5th Int. Workshop on Natural Language Understanding and Logic Programming. Lisbon, Portugal. 199