Utaclir @ CLEF 2001 ― Effects of Compound Splitting and N-Gram Techniques

摘要

The Tampere University CLEF research group participated in CLEF2001 with four automated bilingual runs. Our cross-lingual software, UTACLIR, uses an automated method for query construction for cross-language information retrieval (CLIR). This method seeks to automatically extract topical information from request sentences written in one of the source languages and to create a target language query, based on translations given by a translation dictionary. The new features for the CLIR process from Finnish, Swedish and German to English focus on translating and matching compound words, and a new n-gram based technique for translating and matching proper names and other non-translatable words. Non-translatable words can also be components in compounds. The n-gram based method is clearly efficient in matching inflected proper names and spelling variants. However, using it for all non-identified and non-translatable words adds noise to the query. For German ― English we have tested two types of dictionaries (two runs). The first included all translations from the standard dictionary. The second contained the same data, except that all direct translations of compounds were excluded. The test with two dictionaries for the German runs gives an indication that the new features for compound processing work well even with a limited dictionary.