Die Behandlung übersetzungsambiger Präpositionen im Transfer des VERBMOBIL-Demonstrators

In diesem Report stellen wir ein konzeptbasiertes Verfahren für die Übersetzung von Präpositionen vor, das im Transfer des verbmobil-Demonstrators integriert wurde. Ausgehend von einer Skizze der Probleme, welche sich bei der maschinellen Übersetzung von Präpositionen in spontansprachlichen Äußerungen ergeben, und einer Untersuchung des Übersetzungsverhalten von Präpositionen bzgl. ihres syntaktischen und semantischen Status wird ein konzeptbasiertes Verfahren für ihre Übersetzung entwickelt. Das Übersetzungsverfahren ist zweigeteilt: Unter Anwendung von Abbildungsregeln wird das für die Übersetzung einer quellsprachlichen Präposition relevante bilinguale Konzept identifiziert, aus welchem durch Applikation von Lexikalisierungsregeln die adequate zielsprachliche Präposition generiert wird. Abbildungs- und Lexikalisierungsregeln formulieren die kontextuellen Bedingungen, unter denen die Abbildung auf ein Konzept bzw. seine Lexikalisierung adäquat ist. Die Restriktionen sind in erster Linie an die Sortierung der Argumente der Präposition und teilweise auch an deren referentielle Eigenschaften geknüpft. Desweiteren werden Informationen über den direktionalen bzw. statischen Gebrauch der Präposition einbezogen, die bereits in der Semantikkonstruktion identifiziert werden. Die Anwendung der Regeln erfolgt durch Unifikation und Typinferenz über einer Sorten- und Relationenhierarchie

A minimal transfer conception for Verbmobil

In this paper we introduce the transfer conception MinT that is currently being developed for the prototype of the face-to-face translation system verbmobil. The acronym MinT stands for Minimal Transfer. MinT is a semantic-oriented transfer model that is based on some central ideas of the MRS-based approach outlined in [Copestake et al., 1995], and the Shake-and-Bake approach to machine translation sketched in [Whitelock, 1992]. The central idea of minimal transfer is to relate the source and target language semantic descriptions on a maximal abstract level, without falling back into the well-known problems of the Interlingua approach. Minimal transfer results in simultaneously decreasing the number of transfer rules and leaving a maximal set of options for lexicalization and grammaticalization up to the generator. In sum, MinT can be characterized as a semantic-oriented, unification-based and lexicalist transfer model. Its main knowledge base are transfer statements which provide the correspondences between underspecied semantic predicates of the source and target language. Transfer statements comprise both bilingual and monolingual correspondences. Bilingual correspondences, on the one hand, establish the equivalence between sets of semantic predicates of the source and target languages. They are formulated in a strictly declarative way and can be applied bidirectionally. In order to solve translational ambiguities, the roles and instances of a predicate are typed with fine-grained sorts that are supplied by an elaborated sort hierarchy. Monolingual correspondences, on the other hand, provide a solution to divergences in the logical structure of the languages involved. The idea is to allow the transfer component to initiate further compositional processes if this is motivated by the contrastive situation. Thus, the input structure is transformed into a logically equivalent semantic representation that is shared by the target language. This way, all contrastive knowledge is contained in the transfer component, which allows strict modularity of analysis and generation

What you always wanted to know about semantic transfer

The transfer in Verbmobil is primarily semantic-based. To further move up the level of abstractness, it integrates a variety of interlingual elements that allow the generation of alternative translations. In this report, we present the treatment and implementation of translational phenomena on both levels. Concerning the conceptual mapping level, we focus on problems of lexical and structural abstraction by generalization and decomposition. With respect to the semantic mapping level, we give an insight into the treatment of a wide range of structural divergences. Another topic of this report is the resolution of translational ambiguities which is relevant on both mapping levels. A catalog of examples will provide an overview over the various types of contextual constraints used for disambiguation

Abstraction and underspecification in semantic transfer

This paper introduces the semantic transfer approach MinT (Minimal Transfer) that has been developed in the speech-to-speech MT system VERBMOBIL. As a unification-based and lexicalist semantic transfer model, it relies on some central ideas of the MRS-based transfer approach outlined in [Copestake et al., 1995]. It differs, however, from the latter in certain aspects: in MinT, the idea of abstraction and underspecification is worked out in much more detail and has been applied to a variety of translation phenomena. MinT relates SL and TL semantic descriptions on a maximally abstract level, which results in simultaneously decreasing the number of transfer rules and leaving a considerable amount of options for lexicalization and grammaticalization up to the generator. To preserve ambiguities that hold across the involved languages MinT processes underspecified semantic representations

Dialogue acts in Verbmobil 2

This report describes the dialogue phases and the second edition dialogue acts which are used in the VERBMOBIL 2 project [...]. While in the first project phase the scenario was restricted to appointment scheduling dialogues, it has been extended to travel planning in the second phase with appointment scheduling being only a part of the new scenario

Restricting Bidirectional Translation Correspondences to . . .

This paper addresses the resolution of translational ambiguities in a lexicalist transfer approach, which is realized in the translation system Verbmobil. It is particularly concerned with the use of various kinds of constraints that restrict the translation mapping of ambiguous lexical items to the appropriate context. They range from structural, semantic and prosodic information to discourse and speech act information