The importance of cross-lingual information for matching Wikipedia with the Cyc ontology. ?

Abstract

In this paper we try to answer the question how cross-lingual evidence may improve matching between dierent classication schemas. We concentrate specically on the task of mapping between Wikipedia categories and Cyc terms as well as the classication of Wikipedia articles to the Cyc taxonomy and show how this process may be improved by consuming the evidence that is available in dierent editions of Wikipedia. The results show that the performance of the mapping procedure may be improved from 0.6 to 4.9 percentage points, depending on the number of external Wikipedia editions and the given task.

Keywords

• Ontology
• ontology mapping
• classication
• multilingual data
• Wikipedia
• Cyc

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To answer the question how the additional Wikipedia editions inuence the performance of the mapping between Wikipedia and Cyc (cf. [ 2 ]) we have dened the following tasks: 1) mapping of the Wikipedia categories to Cyc terms; 2) classication of the Wikipedia articles to the Cyc ontology based on the rst sentences. In each case the decision of selecting the corresponding Cyc term requires disambiguation of some English expressions against the Cyc ontology. This decision is based on the contextual data that are available for each Wikipedia article and category. Consulting of the supplementary Wikipedia editions extends the context available when making the decision and in general should improve the performance of the corresponding algorithms.

In case of the category mapping (based on the identication of plural head nouns in category names cf. [ 3 ]), when an English category is mapped, the corresponding Dutch, German, etc. categories are inspected. Then the parent and

Aleksander Smywi«ski-Pohl and Krzysztof Wrbel child categories as well as articles of the corresponding categories in the other editions are looked up in a reverse interlingual mapping index and if there is an English Wikipedia page, that was not present in the original context, it is included in the new, extended context. Then a support value used to disambiguate the category is computed against the extended context.

In case of article classication (based on the rst sentence parsing, cf. [ 1 ]) the supplementary Wikipedia editions provide additional categories for the classied article, that are used to verify the disambiguation decision. The manner of operation is similar to that from the previous task the corresponding articles in other Wikipedia editions are consulted, their categories are translated back to English and these new categories are included in the extended context. 2

Results There was a small improvement (F1 increased from 86.8% to 78.4%) in the performance of the category mapping when the English Wikipedia is supported by three other Wikipedias ( de,nl,sv). However providing the algorithm with more data from other Wikipedia editions, increased the computation time, but did not further improve the results.

On the other hand the inuence of the additional Wikipedia editions in the task of the classication of the articles into the Cyc ontology was much stronger. Not only the additional Wikipedia editions improved the recall, but also the precision. The maximum precision was achieved for 5 and 6 additional Wikipedias (96.6% compared to 95.8% for the sole English Wikipedia). The F1 was the largest for the 8 additional Wikipedias resulting in an increase from 66.2% to 71.1%.

The overall conclusion from the results is that the inuence of the supplementary Wikipedias is task dependant and in general the extra time necessary to pre-process the data and the increase of the computation time may not be justied. However the task of articles classication shows also that such supplementary data may be very valuable and may increase both the precision and the recall of the results.

References

1. Gangemi , A. , Nuzzolese , A.G. , Presutti , V. , Draicchio , F. , Musetti , A. , Ciancarini , P. : Automatic typing of DBpedia entities . In: The Semantic WebISWC 2012 , pp. 6581 . Springer ( 2012 )

2. Pohl , A. : Classifying the Wikipedia Articles into the OpenCyc Taxonomy . In: Rizzo, G. , Mendes , P. , Charton , E. , Hellmann , S. , Kalyanpur , A . (eds.) Proceedings of the Web of Linked Entities Workshop in conjuction with the 11th International Semantic Web Conference . pp. 516 ( 2012 )

3. Suchanek , F. , Kasneci , G. , Weikum , G.: YAGO: a core of semantic knowledge . In: Proceedings of the 16th international conference on World Wide Web . pp. 697706 . ACM ( 2007 )