Comparison Between Manually and Automatically Assigned Descriptors Based on a German Bibliographic Collection

This paper compares and illustrates the use of manually and automatically assigned descriptors on German documents extracted from the GIRT Corpus. A second objectives to analyze the usefulness of both specialized or general thesauri to automatically enhance queries. To illustrate our results we use different search models such as a vector space model, a language model and two probabilistic models. We also proposed different measures to compute textual entailment between two terms allowing us to hopefully select appropriate keywords from thesauri to expand documents or queries automatically.