Ernst Buchberger

Relating syntax and semantics: the syntactico-semantic lexicon of the system VIE-LANG

This paper describes the structure and evaluation of the syntactico-semantic lexicon (SSL) of the German Natural Language Understanding System VIE-LANG [3]. VIE-LANG uses an SI-Net [2] as internal representation. The SSL contains the rules according to which the mapping between net-structures and surface structures of a sentence is carried out. This information is structured in a way that it can be evaluated from two sides. The parser interprets it as production-rules that control the analysis. Syntactic and semantic features of the input sentence are evaluated and individuals are created in the semantic net. The generator uses the same rules to express selected net-structures in adequate natural language expressions. It is shown how both processes can make effective use of the SSL. The different possibilities for evaluating the SSL are explained and illustrated by examples.

DATENBANK-DIALOG: a German language interface for relational databases

Abstract Datenbank-DIALOG is a German language interface for relational databases. Its goal is to provide easy and efficient access to the contents of such a database for casual users. The user has only to type in his or her question in plain German and the system will respond properly. This is much easier than using a formal query language and more flexible than a menu-type or graphic interaction. Datenbank-DIALOG was designed to be as portable as possible, in particular with regard to the application domains as well as the database management system and the operating system of the supporting computer. Equally important was good coverage of the subset of German relevant for database retrieval. German was chosen because we feel that at present it is not feasible to design a parser adaptable to different natural languages, at least not in a satisfying manner. As a result of this specialization Datenbank-DIALOG imposes almost no syntactic restrictions on the user, and care has been taken to make the semanti...

Towards the automatic acquisition of lexical data

Creating a knowledge base has always been a bottleneck in the implementation of AI systems. This is also true for Natural Language Understanding (NLU) systems, particularly for data-driven ones. While a perfect system for automatic acquisition of all sorts of knowledge is still far from being realized, partial solutions are possible. This holds especially for lexical data. Nevertheless, the task is not trivial, in particular when dealing with languages rich in inflectional forms like German. Our system is to be used by persons with no specific linguistic knowledge, thus linguistic expertise has been put into the system to ascertain correct classification of words. Classification is done by means of a small rule based system with lexical knowledge and language-specific heuristics. The key idea is the identification of three sorts of knowledge which are processed distinctly and the optimal use of knowledge already contained in the existing lexicon.

VIE-LANG: A GERMAN LANGUAGE DIALOGUE SYSTEM

Abstract The paper gives a general description of VIE-LANG, a natural language understanding system for German. The components of the system are strongly based on semantics. The central component is a Structured Inheritance Network, which is the source of real world knowledge for all processes of the system. VIE-LANG is designed to engage in dialogues in German. Due to our focus of interest in methodology of representation we chose an approach independent of the intended domain. The designated area of application will be medicine.

Knowledge Acquisition in the System VIE-LANG

In this paper an automated knowledge acquisition system for the Natural Language Dialogue System VIE-LANG is described. Data-driven processing of natural language requires a large and detailed body of knowledge. To build up a complete knowledge base for any real world application by hand is a very cumbersome task. In order to ease the acquisition of new knowledge we have developed a system which is able to extend an existing knowledge base in an automated way. The user who inputs the data needs no specific knowledge of the system or the way data are represented in it. The approach is described in some detail and further explained by means of an example.

An expert advising system with acoustic output

In this paper we describe the application of natural language processing and speech techniques to improve the user-interface of expert systems. The particular goal of our project was to develop a German language interface for expert systems using speech input and output. The interface design was chosen in a way to provide for portability and flexibility. Possible application areas are domains where the users vision is occupied by some task and where the dialogue is mostly system-driven, i.e., the users answers can be restricted to a small set of utterances.