OASIS at NTCIR-6: On-line Query Translation for Chinese-Japanese Cross-Lingual Information Retrieval

This paper reports results of Chinese – Japanese CLIR experiments using on-line query translation techniques. Approaches to employ English as a pivot language and to utilize several on-line translation systems are introduced. They were tested on NTCIR – 3, 4, 5, and 6 collections. Proposed procedures can be helpful under certain circumstances. 1 On-line translation techniques We worked with different on-line translation systems. Techniques which do not require utilizing training data and adjusting the parameters of the retrieval system were applied. Our strategy was as follows: o Apply on-line systems to translate queries directly from Chinese into Japanese, o Utilize the model of Chinese – English – Japanese translation, where English is the pivot language, o Merge the translation results produced by different systems for the possible expansion of queries. We employed Mecab as a segmentation tool. The vector space model was the basis of our search engine. We used information about the part of speech of the words generated by the morphological analyzer: Nouns and verbs were filtered in the “D” runs. Table 1. Results of experiments Run R-Precision Precision at 5 docs Precision at 10 docs Comments OASIS-C-J-T-03 (WorldLingo, Excite) 0.13 0.20 0.18 Merging results of two on-line translation systems, (Stage 1, “Relaxed” relevance judgment) Babel Fish 0.0955 0.1600 0.1300 DictDotCom 0.1112 0.1760 0.1620 Google 0.1163 0.1840 0.1680 Google – Babel Fish 0.1087 0.1840 0.1640 Babel Fish – Google 0.1068 0.1800 0.1620 DictDotCom – Babel Fish 0.1008 0.1720 0.1480 Google – DictDotCom 0.1139 0.1680 0.1620 English as a pivot language (Stage 1, “Relaxed” relevance judgment, “T” runs) OASIS-C-J-D-01-N3 (WorldLingo, Excite) 0.1336 0.1952 0.1643 Merging results of two on-line translation systems, (Stage 2, “Rigid” relevance judgment) 0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 Topics P re c is io n