• Proceedings of the Korean Information Science Society Conference
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• 2004.10b
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• pp.160-162
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• 2004

인터넷에서 XML은 새로운 정보 환경의 요구사항인 확장성과 문서 관계성의 우수성을 만족하는 표준이다. 이러한 XML 문서 안의 정보 검색을 위해서 XPath 질의어가 널리 사용 중이다. 또한, XML 문서의 체계적인 운용을 위해 데이터베이스에 효율적으로 저장하고 검색하는 연구들이 진행되고 있다. 본 연구에서는 분할 저장 시스템에서 RDBMS 또는 ORDBMS에 XML 문서를 저장하고 검색할 수 있도록 하는 XPath 질의 처리기를 SQL:1999를 이용하여 설계함으로써 좀더 정확하고 빠르게 처리가 가능하도록 하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.11a
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• pp.47-50
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• 2004

XML 은 데이터 저장과 전송을 위한 수단으로 자리잡아 가고 있으며, 관계형 DBMS를 이용해서 효과적으로 대용량의 XML 데이터의 저장과 검색에 관한 연구가 진행 되고 있다. 본 논문에서는 기 제안된 XPath Accelerator 라는 XML 데이터 인덱스 메커니즘을 상용 관계형 DBMS를 활용해서 구현하고, 이를 해당 DBMS 상에서 최대한의 성능을 위해 튜닝하는 방안을 기술한다. 이를 위해 XBench 라는 XML 전용 벤치마크 데이터를 활용해서 XPath Accelerator 의 문제점과 향후 개선 방안에 대해서도 논의한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.55-57
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• 2002

XML은 확장성, 호환성, 정보의 구조화의 우수성으로 인터넷상에서 정보 교환의 표준으로 자리 매김하고 있다 그러나 대부분의 비즈니스 데이터는 관계형 데이터베이스 시스템에 저장되어 있고 앞으로도 상당한 기간 동안 그러할 것이다. 이에 따라. 관계형 데이터를 XML 문서로 변환, 출판하기 위한 연구가 활발히 진행 중이다. 본 연구에서 관계형 데이터를 XPATH 질의어를 동하여 검색하고 XML 문서로 변환하기에 적합하도록 관계형 데이터베이스의 저장 스키마를 설계하였다. 그리고, XPATH 질의어를 SQL 문장으로 변환하여 관계형 데이터를 검색하였고, 질의 결과를 DOM 형식의 XML 문서로 생성하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.5
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• pp.877-895
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• 2010

The state-of-the-art techniques of storing XML data, modeled as an XML tree, are node-based in the sense that they are centered around XML node labeling and the storage unit is an XML node. In this paper, we propose a generalization of such techniques so that the storage unit is an XML subtree that consists of one or more nodes. Despite several advantages with such generalization, a major problem would be inefficiency in XPath processing where the stored subtrees are to be parsed on the fly in order for the nodes inside them to be accessed. We solve this problem, proposing a technique whereby no parsing of the subtrees involved in XPath processing is needed at all unless they contain the nodes of the final query result. We prove that the correctness of XPath processing is guaranteed with our technique. Through implementation and experiments, we also show that the overhead of our technique is acceptable.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04b
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• pp.10-12
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• 2004

Nowadays, with the rapid emergence of XML as a standard for data exchange over the Internet had led to considerable interest In the problem of data management requirements such as the need to store and query XML documents in which the location path languages Xpath is of particular important for XML application since it is a core component of many XML processing standards such as XSLT or XQuery, This parer gives a brief overview about method and design by applying a new spatial-based indexing method namely Xp-free that used for supporting Xpath. Spatial indexing technique has been proved its capacity on searching in large databases. Based on accelerating a node using planar as combined with the numbering schema, we devise efficiently derivative algorithms, which are simple, but useful. Besides that, it also allows to trace all Its relative nodes of context node In a manner supporting queries natural to the types especially Xpath queries with predicates.

• The KIPS Transactions:PartD
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• v.12D no.2 s.98
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• pp.189-198
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• 2005

XML is rapidly becoming the standard for data representation and exchange, and XML documents are being adopted in various applications. Since the late 1990s, some native XML database management systems(DBMSs) have been developed. More recently, commercial relational DBMS vendors try to incorporate full functionalities of XML into their products, such as Oracle, MS SQL and IBM DB2. In this paper, we implement a well-known RDBMS-based XML data storage and indexing technique, called XPath Accelerator, and tune it in an industry-leading RDBMS. Our contributions are two-folds: 1) an in-depth implementation of the XPath Accelerator technique and 2) its tuning to exploit the advanced query processing techniques of an RDBMS.

• Journal of KIISE:Databases
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• v.33 no.5
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• pp.437-452
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• 2006

In this paper, we propose an extended XPath specification which includes a special matching character '%' used in the LIKE operation of SQL in order to solve the difficulty of writing some queries to filter element contents well, using the previous XPath specification. We also present a novel technique for filtering a collection of document-centric XMLs, called Pfilter, which is able to exploit the extended XPath specification. Owing to sharing the common prefix characters of the operands in value-based predicates, the Pfilter improves the performance in processing those. We show several performance studies, comparing Pfilter with Yfilter in respect to efficiency and scalability as using multi-query processing time (MQPT), and reporting the results with respect to inserting, deleting, and processing of value-based predicates. In conclusion, our approach provides a core algorithm for evaluating the contains() function of XPath queries in previous XML filtering researches, and a foundation for building XML-based distributed information systems.

• The KIPS Transactions:PartD
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• v.15D no.4
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• pp.441-450
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• 2008

Recently, access control on form-based web information systems has become one of the useful methods for implementing client systems in a service-oriented architecture. In particular, XForms language is being adopted in many systems as a description language for XML-based user interfaces and server interactions. In this paper, we propose an efficient algorithm for the evaluation of XPath-based access rules for XForms pages. In this model, an XForms page is a sequence of queries and the client system performs user interface realization along with XPath rule evaluations. XPath rules have instance-dependent predicates, which for the most part are shared between rules. For the efficient evaluation of shared predicate expressions in access control rules, we proposed a predicate graph model that reuses the previously evaluated results for the same context node. This approach guarantees that each predicate expression is evaluated for the relevant xml node only once.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.348-351
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• 2008

XML 데이터 사용의 증가와 그 응용분야가 다양해짐에 따라 무선 방송 환경에서 효율적으로 XML 데이터를 전송하기 위한 기법이 요구된다. 본 논문에서는 무선으로 방송되는 XML 스트림에 대하여 복합 XPath 표현식으로 구성되는 질의를 처리하기 위한 기법을 제안한다. XML 스트림은 기존의 반구조적인 데이터의 경로요약 기법을 활용하여 생성한다. 성능평가를 통하여 제안하는 기법이 복합 XPath 표현식이 포함된 질의에 대해서도 에너지 효율적임을 보인다.

• Journal of KIISE:Databases
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• v.35 no.3
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• pp.243-256
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• 2008

With rapid growth of Internet, the amount of information in the Web is increasing exponentially. However, information on the current Web is understandable only for human, and thus it makes the exact information retrieval difficult. For solving this problem, the Semantic Web is suggested and we must use ontology languages that can endow data to semantics for implementing it. One of the representative ontology languages is OWL(Web Ontology Language) adopted as a recommendation by the World-Wide Web Consortium. OWL has richer expression power and formal semantics than other ontology languages such as RDF and RDF-S. In addition, OWL includes hierarchical structure information between classes or properties. Therefore, an efficient OWL storage model considering hierarchical structure for effective information retrieval on the Semantic Web is required. In this paper, we suggest the XPOS(XPath-based OWL Storage) model including hierarchy information between classes or properties as XPath form and enabling intuitive and effective information retrieval. Also, we show the comparative evaluation results on the performance of XPOS model, Sesame, and the XML storage-based storage model regarding query processing.