Kanada's papers

Kanada, Y., Yamazaki, M., Sawada, M., Hirano, Y., and Fujii, Y., 59th National Conference，3P-9, 1999, Information Processing Society of Japan (published by IPSJ)

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Abstract: In the member's only network called "Net-de-hyakka", a service called the thematic mapping search, in which results of encyclopedia text search is ordered along a geographical axis, is offered. In this search, the statements are searched and sorted by geographical names that occur in the text. A map of one of the geographical names can also be opened. The function and implementation method of this search are summarized here.

Introduction to this research theme: Axis-Specified Search (Thematic Search)

Kanada, Y., IPSJ SIGNL Technical Report, 99-NL-132-2, 1999, Published by IPSJ (in Japanese).

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Abstract: A text retrieval method called the thematic mapping search method has been developed for Japanese texts. In this method, the user specifies a search theme using free words, then obtains a sorted list of excerpts and hyperlinks to sentences that contain geographical names. Using this list, the user can open maps that indicate the location of the names. To generate an index of names for this searching, a method of geographical name extraction has been developed. In this method, geographical names are extracted, matched to names in a geographical name database, and identified. Geographical names, however, often have several types of ambiguities. Ambiguities are resolved using context analysis and several other techniques. As a result, the precision of extracted names is more than 96% on average when applied to the World Encyclopedia. The rules for information extraction depends on features of the Japanese language, but the strategy and most of the techniques can be applied to texts in English or other languages.

Introduction to this research theme: Axis-Specified Search (Thematic Search)

Kanada, Y., International Symposium on Digital Library 1999, pp. 135-142, 1999

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Abstract: A method of extracting year references for a textual information retrieval method called the thematic chronological-table search method is explained in this paper. This search method generates an index by extracting and collecting year references from a text collection. The resulting index and a full-text index are used for searching statements that contain year references and search words. The results are displayed in the form of a chronological table with hyperlinks to the original text. Seven forms of year or century references are extracted and normalized using string matching patterns. The extraction error rate is reduced by using both local and nonlocal contexts. If the lower two digits of a Gregorian year, which matches a form, occurs, it is normalized by supplementing the upper digits using the non-local context. This method has been applied to a Japanese encyclopedia. An evaluation shows the precision of extraction to be higher than 99% in most cases.

Introduction to this research theme: Axis-Specified Search (Thematic Search)