• Journal of KIISE:Databases
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• v.32 no.3
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• pp.326-333
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• 2005

Many XML applications use XPath Patterns as a query language for XML documents. Two XPath patterns may have containment relationship, and the containment problem between two XPath patterns is a problem that determines whether one XPath pattern contains another XPath Pattern. Although the containment problem occurs in many applications, it is known as a co-NP complete. A homomorphism problem, which is a sufficient condition for the containment problem, is solved in polynomial time. We first discuss applications that replace the containment problem with the homomorphism problem, and maintaining homomorphism information among XPath patterns will benefit those applications. Then, we propose a lattice structure, called POX (Partially Ordered Set of XPath Patterns), and develop algorithms for maintaining it. As our analyses show, the algorithms can efficiently maintain POX in polynomial time.

• Journal of KIISE:Databases
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• v.32 no.2
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• pp.193-203
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• 2005

XML (extensible Markup Language) is recognized as a standard of data representation and transmission on Internet. XPath is a standard for specifying parts of XML documents anda suitable language for both query processing and access control of XML. In this paper, we use the XPath expression for representing user queries and access control for XML. And we propose an access control method for XML, where we control accesses to XML documents by filtering query XPath expressions through access control XPath expressions. In the proposed method, we directly search XACT (XML Access Control Tree) for a query XPath expression and extract the access-granted parts. The XACT is our proposedstructure, where the edges are structural summary of XML elements and the nodes contain access-control information. We show the query XPath expressions are successfully filtered through the XACT by our proposed method, and also show the performance improvement by comparing the proposed method with the previous work.

• The KIPS Transactions:PartD
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• v.14D no.6
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• pp.605-614
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• 2007

As a standard query language to search XML data, XQuery and XPath were proposed by W3C. By widely using XQuery and XPath languages, recent researches focus on the development of query processing algorithm and data structure for efficiently processing XML query with the enormous XML database system. Recently, when processing XML path expressions, the concept of the structural join which may determine the structural relationship between XML elements, e.g., ancestor-descendant or parent-child, has been one of the dominant XPath processing mechanisms. However, structural joins which frequently occur in XPath query processing require high cost. In this paper, we propose a new structural join algorithm, called SISJ, based on our structured index, called SI, in order to process XPath queries efficiently. Experimental results show that our algorithm performs marginally better than previous ones. However, in the case of high recursive documents, it performed more than 30% by the pruning feature of the proposed method.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.04a
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• pp.57-60
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• 2015

XPath는 XML 문서를 탐색하고 필요한 부분을 추출하는데 유용한 W3C 표준 프로그래밍 언어이다. XPath를 기반으로 XSLT, XQuery와 같은 표준 언어가 정의되어 널리 사용되고 있으며, DTD, XML Schema, RelaxNG와 같은 타입 언어를 이용하여 XML 문서를 효과적으로 명세할 수 있음에도 불구하고, XPath 기반 XML 처리 프로그램을 위한 타입 검사 기법은 미비하다. 본 논문에서는 XPath 기반 프로그램을 위한 새로운 양상논리 기반의 타입 추론 기법을 제안한다.

• Journal of the Korea Society of Computer and Information
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• v.20 no.7
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• pp.1-7
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• 2015

Although data on the internet can be used in various fields such as source of data of IR(Information Retrieval), Data mining and knowledge information servece, and contains a lot of unnecessary information. The removal of the unnecessary data is a problem to be solved prior to the study of the knowledge-based information service that is based on the data of the web page, in this paper, we solve the problem through the implementation of XTractor(XPath Extractor). Since XPath is used to navigate the attribute data and the data elements in the XML document, the XPath analysis to be carried out through the XTractor. XTractor Extracts main text by html parsing, XPath grouping and detecting the XPath contains the main data. The result, the recognition and precision rate are showed in 97.9%, 93.9%, except for a few cases in a large amount of experimental data and it was confirmed that it is possible to properly extract the main text of the news.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.52-54
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• 2002

인터넷에서 XML은 고유의 확장성과 문서 관계성의 우수성을 활용하여 새로운 정보 공유 환경의 표준으로 자리잡고 있으며 XML문서 안의 정보 검색을 위해서 XPath 질의어가 널리 사용 중이다. 따라서, XML 문서를 데이터베이스에 효율적으로 저장하고 검색하는 연구들이 진행되고 있다. 본 연구는 관계형 데이터베이스(RDBMS)를 통하여 XML문서를 저장하고 검색할 수 있게 하기 위해 XPath 질의어에 적합하도록 하부 저장 스키마를 설계하였다. 그리고, XPath 질의를 SQL문으로 변화시켜 수행함으로써 XML 데이터에 대한 접근을 허용하였다. 더욱이 SQL문 수행 후의 결과를 효율적으로 DOM 형식의 XML 문서를 생성시킴으로써 문서의 재 조작을 가능하게 하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10c
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• pp.235-239
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• 2006

최근 컴퓨팅 환경은 인터넷 환경의 웹을 기반으로 한 분산 컴퓨팅 환경으로 변화하고 있다. 그에 따라 XML 문서의 사용과 XML 문서의 양이 급속하게 증가하였으며, 언제라도 쉽게 필요한 XML 문서에 접근할 수 있어야 한다. XML 문서에서 정보를 검색하기 위하여 XPath 질의어가 널리 사용 중이며, XML 저장 기법과 XPath를 이용한 질의 처리에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 분산 객체 관계 데이터베이스 시스템을 이용하여 XML 문서를 저장하고 관리하는 시스템을 설계하였으며 분산된 XML 데이터를 접근할 수 있도록 하기 위해 XPath를 분산 SQL로 변환하여 실행하는 분산 XPath 질의 처리기를 설계 및 구현하였다.

• Journal of Korea Multimedia Society
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• v.15 no.9
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• pp.1133-1148
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• 2012

This paper presents a hierarchical structuring method for the multidimensional type inheritance indices (MD-TIXs) that support the processing of XML queries in XML databases. MD-TIX uses a multidimensional index structure for efficiently supporting ancestor-descendant explorations that involve both nested element and type inheritance hierarchies. However, In the case of a long Xpath, the building and maintenance of MD-TIX are very difficult because of index entry construction problem. So, we propose a type inheritance index hierarchy method for solving this difficulty. We first construct base indices that support direct relationship explorations between adjacent two types on a given Xpath, and then, based on these base indices, we construct hierarchically the derived indices that support indirect relationship explorations between any two types of Xpath until constructing one target index for supporting the full Xpath. And we also present an algorithm that efficiently constructs a partial index hierarchy for supporting given a set of sub-pathes explorations.

• Journal of KIISE:Databases
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• v.35 no.4
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• pp.307-318
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• 2008

One of the primary issues confronting XML message brokers is the difficulty associated with processing a large set of continuous XPath queries over incoming XML seams. This paper proposes a novel system designed to present an effective solution to this problem. The proposed system transforms multiple XPath queries before their run-time into a new region-based data structure, called an XP-table, by sharing their common constraints. An XP-table is matched with a stream relation (SR) transformed from a target XML stream by a SAX parser. This arrangement is intended to minimize the runtime workload of continuous query processing. Also, system performance is estimated and verified through a variety of experiments, including comparisons with previous approaches such as YFilter and LazyDFA. The proposed system is practically linear- scalable and stable for evaluating a set of XPath queries in a continuous and timely fashion.

• Journal of the Korea Society of Computer and Information
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• v.14 no.3
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• pp.57-64
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• 2009

XML has become a do facto standard for structured document and data on the Web. An XML data deluge over the network will be more, since XML based standards such as Web Service and Semantic Web gets popular. There are efforts to store and query XML documents in a relational database system and recent efforts focus on how to provide such operations using XPath and XQuery. In this paper, we present study about those research efforts and we propose a new scheme to stoγe and query XML documents in a relational database using XPath query. The scheme uses a 'shred' method to store and translates XPath queries to SQL. We also present our empirical experiments using a RDBMS.