• Journal of KIISE:Software and Applications
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• v.27 no.1
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• pp.84-95
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• 2000

In this paper, we propose an integrated indexing method with compound noun segmentation and noun phrase synthesis. Statistical information is used in the compound noun segmentation and natural language processing techniques are carefully utilized in the noun phrase synthesis. Firstly, we choose index terms from simple words through morphological analysis and part-of-speech tagging results. Secondly, noun phrases are automatically synthesized from the syntactic analysis results. If syntactic analysis fails, only morphological analysis and tagging results are applied. Thirdly, we select compound nouns from the tagging results and then segment and re-synthesize them using statistical information. In this way, segmented and synthesized terms are used together as index terms to supplement the single terms. We demonstrate the effectiveness of the proposed integrated indexing method for Korean compound noun processing using KTSET2.0 and KRIST SET which are a standard test collection for Korean information retrieval.

• Language and Information
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• v.6 no.2
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• pp.83-104
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• 2002

I argue that Definiteness Effect (DE) should include Indefiniteness Restriction (IR) as well as Definiteness Restriction (DR). DR is exhibited by existential constructions, predicate nominals, inalienable possession constructions, and verbs with semantic features like 〔((CAUSE TO) COME TO) EXIST〕. IR is caused by some existence presupposition of aspectual adverbs, aspectual verbs, repetitives, and topic markers. The environments for DR and IR determine the (in)definiteness of Korean bare noun phrases which otherwise can be used either way. The neutralization of DR is also induced by focus which imposes a certain amount of structure on the event quantification. Van der Sandt's (1992) Presuppositions-as- Anaphora-Theory is effectively used to account for those examples from DR, ID, and the neutralization of BR.

• Journal of KIISE:Software and Applications
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• v.26 no.10
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• pp.1219-1229
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• 1999

일반적으로 AND, OR, NOT과 같은 연산자를 사용하는 불리언 질의는 사용자의 검색의도를 정확하게 표현할 수 있기 때문에 검색 전문가들은 불리언 질의를 사용하여 높은 검색성능을 얻는다고 알려져 있지만, 일반 사용자는 자신이 원하는 정보를 불리언 형태로 표현하는데 익숙하지 않다. 본 논문에서는 검색성능의 향상과 사용자 편의성을 동시에 만족하기 위하여 사용자의 자연어 질의를 확장 불리언 질의로 자동 변환하는 방법론을 제안한다. 먼저 자연어 질의를 범주문법에 기반한 구문분석을 수행하여 구문트리를 생성하고 연산자 및 키워드 정보를 추출하여 구문트리를 간략화한다. 다음으로 간략화된 구문트리로부터 명사구를 합성하고 키워드들에 대한 가중치를 부여한 후 불리언 질의를 생성하여 검색을 수행한다. 또한 구문분석의 오류로 인한 검색성능 저하를 최소화하기 위하여 상위 N개 구문트리에 대해 각각 불리언 질의를 생성하여 검색하는 N-BEST average 방법을 제안하였다. 정보검색 실험용 데이타 모음인 KTSET2.0으로 실험한 결과 제안된 방법은 수동으로 추출한 불리언 질의보다 8% 더 우수한 성능을 보였고, 기존의 벡터공간 모델에 기반한 자연어질의 시스템에 비해 23% 성능향상을 보였다. Abstract There have been a considerable evidence that trained users can achieve a good search effectiveness through a boolean query because a structural boolean query containing operators such as AND, OR, and NOT can make a more accurate representation of user's information need. However, it is not easy for ordinary users to construct a boolean query using appropriate boolean operators. In this paper, we propose a boolean query formulation method that automatically transforms a user's natural language query into a extended boolean query for both effectiveness and user convenience. First, a user's natural language query is syntactically analyzed using KCCG(Korean Combinatory Categorial Grammar) parser and resulting syntactic trees are structurally simplified using a tree-simplifying mechanism in order to catch the logical relationships between keywords. Next, in a simplified tree, plausible noun phrases are identified and added into the same tree as new additional keywords. Finally, a simplified syntactic tree is automatically converted into a boolean query using some mapping rules and linguistic heuristics. We also propose an N-BEST average method that uses top N syntactic trees to compensate for bad effects of single incorrect top syntactic tree. In experiments using KTSET2.0, we showed that a proposed method outperformed a traditional vector space model by 23%, and surprisingly manually constructed boolean queries by 8%.