Rainer Osswald

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We describe how a feature-based semantic lexicon can be automatically extended using large, unstructured text corpora. Experiments are carried out using the lexicon HaGenLex and the Wortschatz corpus. The semantic classes of nouns are determined via the adjectives that modify them. It turns out to be reasonable to combine several classifiers for single(More)
Preface Representing and reasoning with ontologies is the core technology for the Semantic Web, and is growing in importance in many other areas of Computer Science where structured and hierarchically organized knowledge is of importance. While the need for ontological knowledge representation formalisms for practical applications is abundant, it is(More)
We present a flexible approach for extracting hierarchical classifications from linguistic data. To this end, the framework of observational logic is introduced, which extends the logic that underlies standard Formal Concept Analysis by allowing disjunctive rules and exclusions. We give a rigorous mathematical characterization of how the chosen rule type(More)
The proper interpretation of prepositions is an important issue for automatic natural language understanding. We present an approach towards PP interpretation as part of a natural language understanding system which has been successfully employed in various NLP tasks for information retrieval and question answering. Our approach is based on the so-called(More)
In the so-called information society with its strong tendency towards individualization, it becomes more and more important to have all sorts of textual information available in a simple and easy to understand language. We present an approach that allows to automatically rate the readability of German texts and also provides suggestions how to make a given(More)
We describe the treatment of verbs with prepositional complements in HaGenLex, a semantically based computer lexicon for German. Prepositional verbs such as bestehen auf ('insist on') subcategorize for a prepositional phrase where the preposition usually has no independent meaning of its own. The lexical semantic information in HaGenLex is specified by(More)