• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.19-27
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• 2006

This paper presents a query processing model in a wrapper based on the XML view tree. The query processing in a wrapper requires view composition, query translation into local sources, and generation of XML documents from local query results. We present a query processing model based on the view tree, where the XML views and the XML query is represented by the view tree. Since the view tree keeps the structure of a virtual XML document, it is easy to navigate the path expression. The view tree is also used as a template for schema generation and XML document generation as a query result. Moreover this conceptual uniform abstraction for the XML view and the user query makes it easy to support a multi-level XML view and to implement our composition mechanism.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.63-66
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• 2006

실체화 뷰 선택은 질의 수행 시간과 제한된 저장 공간 등의 유지 비용을 고려하여 최적의 실체화 뷰 집합을 선택하고 유지하는 것이다. 본 논문에서는 의사결정 트리를 이용한 실체화 뷰 선택기법을 제안한다. 제안기법은 의사결정 트리를 이용하여 실체화 뷰로 생성될 질의를 판단하고 실체화 뷰 교체가 필요한 경우 메타데이터 테이블을 이용하여 교체 대상을 결정한다. 의사결정 트리는 높은 우선순위를 가진 속성으로부터 차례대로 데이터를 분류하기 때문에 이용도가 높은 실체화 뷰를 선택하는 방법을 제공하고 메타데이터 테이블은 실체화 뷰 집합의 빠른 교체 수행과 효율적인 유지보수를 제공한다. 성능평가를 통해 제안된 기법은 실체화 뷰 비율에 따른 질의처리 시간이 기존기법보다 약 13%의 성능 향상을 보였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.11c
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• pp.1481-1484
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• 2003

XML 뷰 기반의 랩퍼 시스템은 지역 데이터베이스에 대한 XML 뷰 정의를 지원하고, 사용자는 XML 질의어를 이용하여 XML 뷰에 대한 질의를 할 수 있다. 이 때, XML 뷰와 질의간의 합성이 필수적인데, 본 논문에서는 XML 뷰와 사용자 질의를 높은 수준에서 추상화하여 모두 트리로 표현하고, 이것을 이용하여 질의에 나타난 뷰의 경로식에 대한 항해를 통해 합성을 수행하는 모델을 제시한다. 뷰 트리는 가상의 XML 문서의 구조를 그대로 반영하기 때문에 경로식의 항해를 쉽게 하며, XML 뷰의 스키마를 생성하고, 질의 결과 문서를 구성하는 템플릿으로 활용된다. 또한, XML 뷰와 질의의 추상화된 개념적 통일은 다단계 XML 뷰 정의와 합성을 지원하고, 구현을 용이하게 한다.

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.47-48
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• 2015

본 논문에서는 의사 분산 트리를 이용하여 효율적으로 후보 실체 뷰를 선택하는 기법을 제안한다. 제안하는 기법은 후보 실체 뷰의 이득, 실체화 크기, 그리고 갱신율을 고려하여 의사 결정 트리로 구축한다. 의사 결정 트리를 이용하여 효율이 높은 후보 실체 뷰의 선택 및 빠른 교체 수행을 목적으로 한다.

• The Journal of the Acoustical Society of Korea
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• v.23 no.5
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• pp.390-399
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• 2004

In this paper, we design and implement a multiple-view VoiceXML editor to improve editing efficiency of the VoiceXML. The VoiceXML multiple-view Editor uses a MVC framework to support multiple views and paradigm. Our multiple-view editor consists of Model. View and Controller using MVC framework. A model, core data structure. is constructed of abstract syntax tree and abstract grammar. A view. user interface. is formalized in unparsing rules and unparser. A controller. to control model and view. is made of command interpreter and tree handler. The VoiceXML multiple-view editor overcomes a drawbacks of existing XML editors by showing document structure and context concurrently. as well as document flows. Our VoiceXML multiple-view editor. which MVC framework has been applied, provides various editing views concurrently to users. Thereby. it supports efficient and convenient editing environments for voice-web documents to users and it guarantees transparency of editors. as various views have a same consistent model.

• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.24-34
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• 2015

With the development of the semantic web, a large amount of data being produced nowadays is in RDF format. RDF is represented by a triple. An RDF database consisting of triples requires the high cost of join query processing. Materialized view is known as a scheme to reduce the query processing cost by accessing materialized views without accessing the database. It is physically stored the results or the intermediate results of the query processing in a storage area. In this paper, we propose a materialized view selection scheme by using decision tree to solve such a problem. The decision tree considers the size and maintenance costs of the materialized view as well as the profit of query response times. It is shown through performance evaluation that the proposed scheme increases the number of materialized views in the limited storage space and decreases the update rates of the materialized views.

• Proceedings of the Korean Information Science Society Conference
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• 2001.04b
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• pp.163-165
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• 2001

데이터웨어하우스 환경에서는 범위-집계 질의를 효율적으로 수행하기 위해 데이터큐브로 저장뷰를 구성한다. 큐브트리란 이러한 저장뷰를 R-Tree형태로 구성하는 기법으로, 효율적인 데이터 접근성을 제공하지만 범위-집계 질의 범위 내의 모든노드를 접근해야 하는 단점이 있다. 이 논문에서는 중간노드의 MBR에 자식 노드 레코드들의 집단함수 값을 저장하여, 질의 범위에 포함되는 중간노드의 경우 단말노드를 접근하지 않고 효율적으로 범위-집계 질의를 수행할 수 있는 집계큐브트리를 제안하였다. 집계큐브트리는 기존의 큐브트리에 비해, 항상 적은 수의 노드 접근으로 질의를 수행하며 질의 범위의 크기가 커질수록 좋은 성능을 보인다.

• The KIPS Transactions:PartD
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• v.10D no.3
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• pp.367-374
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• 2003

A mediator-wrapper system, which is one of integration methods of heterogeneous databases, preserves a virtual integrated view rather than physical movement of the contents of each database. In order for a mediator to preserve a virtual integrated view, it requires the schema manager of the wrapper which communicates with local databases. This paper presents a schema manager of a wrapper that provides a mediator with XML schema which is generated from relational database schema. The XML schema manager supports a user-defined XML view. We present the view tree model which is used for materializing the use-defined XML view to generate XML schema, and the conversion algorithm based on the proposed view tree model. This model is can be uniformly applied to all schema managers of heterogeneous information sources.

• The KIPS Transactions:PartD
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• v.12D no.4 s.100
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• pp.553-568
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• 2005

In order to integrate distributed biological information sources physically or virtually, it is necessary to overcome the heterogeneity of information sources and support a superior generality and adaptation in order to satisfy user's various demands. In this paper, we present a flexible and general XML query engine of a wrapper system in designing the middleware system to integrate data as well as application programs. Since this query engine applies user-defined XML view, it is possible to composite flexible integrated query. The query processing in a wrapper requires view composition, query translation into local sources, and generation of XML documents from local query results. We present a query processing model based on the view tree, where the n views and the XML queries are represented by the view tree. Moreover, to confirm the generality of our query processing model, we present a methodology of query processing for relational databases, web sources, and application programs whose return types of query results are relational tuples or XML documents.

• Journal of the Korea Society of Computer and Information
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• v.3 no.4
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• pp.1-9
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• 1998

Temporal Databases store all of informations by time varying, so the temporal query processor has to process very large information. Therefore, we propose an efficient method of query processing by using the relevance checking algorithm of input query and view definition. The relevance checking algorithm of query investigates relevance between the input query of user about base relation and the execution tree of view definition stored in system catalog. And related input query with view definition have a process of the query translation to the execution tree of view. So temporal query processor is able to increase performance of query processor by reducing the number of tuple.