Korean script searching in Korean Library OPACs

Korean script searching in Korean Library OPACs Junglim Chae Yonsei University

Indexing Method

N-Gram

Morphological Analysis

N-Gram IndexingN-Gram : Unigram, Bigram, Trigram, N-GramE.g.) 12 Index by Bigram Segmentation, , , 0 , 0, , 0 , 0, , , , Many index terms-many results but lots of noise High recall ratio but low precision ratio

Morphological AnalysisRequires a morphological analysis dictionaryE.g.) Three Index by morphological analysis, , Ability to match linguistically similar terms Faster performance with a smaller index Accurate matches that meet user expectationsHigh precision ratio but low recall ratio

N-Gram Vs. Morphological Analysis

N-GramMorphological AnalysisRecall RatioHighLowPrecision RatioLowHighSize of IndexBigSmallIndexing SpeedFastSlowSearch SpeedSlowFastApplicationLibrariesWeb Search Engines

A Case Study

Yonsei University LibraryLibrary System: Maestro-Y Search Engine: K2 by VerityIndexing Method N-Gram (bigram) + Morphological AnalysisIndexing RulesRule1: Divide Strings by space Rule2: Extract index using bigram indexing methodRule3: Add the whole string excluding spaces between strings Rule4: Add words from Korean morphological analysis dictionary

A Case Study

Yonsei University LibraryE.g.)

/ (rule1), , , , (rule2)(rule3)(rule4)Index: , , , , , ,

Search Tips

Search Tips(1)Keyword Search

, Default Search OptionUse at most 3 keywordsUse Boolean operatorsOmit Stop-words

Search Tips(2)Keyword Search

Follow the Korean Word Division Rules E.g.) (O) (X)

Search Tips(3)

Keyword Search

Compound Nounsdo not use spaces between nounsE.g.) (O), (X )

Browse SearchBegin with or Truncation,

When you already know the first word of the title, author, or publisher E.g.)

Search Tips(4)

Browse Search

Korean ClassicsE.g.)

Search Tips(5)

Exact Match

Precise Search

Known itemsE.g.) Search Tips(6)

Exact Match

Single character wordsE.g.) , , C

Search Tips(7)

Support Hangul/Hancha Searching

E.g.) /

Search Tips(8)

Japanese KanaArchaic KoreanRussianSpecial characters : Choose scripts from Multi-language Input Table

Search Tips(9)

E.g.) Multi-Script Input Table

Japanese Kana//

Search Tips(10)

Personal names ; Shakespeare ; Murakami, Haruki ; ; ,

Search Tips(11)

Space Considered as ANDE.g.) = AND In some OPACs, spaces in the character fields do make a difference in retrieval

Search Tips(12)

Comparative search with and without space

Thank You

[email protected]

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