Search (3 results, page 1 of 1)

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Abstract

Die Videos des TIB / AV-Portals werden mit insgesamt 63.356 GND-Sachbegriffen aus Naturwissenschaft und Technik automatisch verschlagwortet. Neben den deutschsprachigen Videos verfügt das TIB / AV-Portal auch über zahlreiche englischsprachige Videos. Die GND enthält zu den in der TIB / AV-Portal-Wissensbasis verwendeten Sachbegriffen nur sehr wenige englische Bezeichner. Es fehlt demnach ein englisches Indexierungsvokabular, mit dem die englischsprachigen Videos automatisch verschlagwortet werden können. Die Lösung dieses Problems sieht wie folgt aus: Die englischen Bezeichner sollen über ein Mapping der GND-Sachbegriffe auf andere Datensätze gewonnen werden, die eine englische Übersetzung der Begriffe enthalten. Die verwendeten Mappingstrategien nutzen die DBpedia, LCSH, MACS-Ergebnisse sowie den WTI-Thesaurus. Am Ende haben 35.025 GND-Sachbegriffe (mindestens) einen englischen Bezeichner ermittelt bekommen. Diese englischen Bezeichner können für die automatische Verschlagwortung der englischsprachigen Videos unmittelbar herangezogen werden. 11.694 GND-Sachbegriffe konnten zwar nicht ins Englische "übersetzt", aber immerhin mit einem Oberbegriff assoziiert werden, der eine englische Übersetzung hat. Diese Assoziation dient der Erweiterung der Suchergebnisse.

Content

Beitrag als ausgearbeitete Form eines Vortrages während des 103. Deutschen Bibliothekartages in Bremen. Vgl.: https://www.o-bib.de/article/view/2014H1S197-204.

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Abstract

The quality of stemming algorithms is typically measured in two different ways: (i) how accurately they map the variant forms of a word to the same stem; or (ii) how much improvement they bring to Information Retrieval systems. In this article, we evaluate various stemming algorithms, in four languages, in terms of accuracy and in terms of their aid to Information Retrieval. The aim is to assess whether the most accurate stemmers are also the ones that bring the biggest gain in Information Retrieval. Experiments in English, French, Portuguese, and Spanish show that this is not always the case, as stemmers with higher error rates yield better retrieval quality. As a byproduct, we also identified the most accurate stemmers and the best for Information Retrieval purposes.

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Abstract

Descriptive metadata play a key role in finding relevant search results in large amounts of unstructured data. However, current scientific audiovisual media are provided with little metadata, which makes them hard to find, let alone individual sequences. In this paper, the TIB / AV-Portal is presented as a use case where methods concerning the automatic generation of metadata, a semantic search and cross-lingual retrieval (German/English) have already been applied. These methods result in a better discoverability of the scientific audiovisual media hosted in the portal. Text, speech, and image content of the video are automatically indexed by specialised GND (Gemeinsame Normdatei) subject headings. A semantic search is established based on properties of the GND ontology. The cross-lingual retrieval uses English 'translations' that were derived by an ontology mapping (DBpedia i. a.). Further ways of increasing the discoverability and reuse of the metadata are publishing them as Linked Open Data and interlinking them with other data sets.

Series

Communications in computer and information science; 544