• Journal of KIISE:Computing Practices and Letters
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• v.16 no.3
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• pp.324-330
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• 2010

XML schema is widely used as an effective tool for organizing and validating XML data. Although W3C released XQuery and XQuery Update Facility as the standard methods for searching and updating XML data, there is no consideration about providing facilities for updating XML schema itself until now. So users can only update an XML schema file directly by using editors. However, the direct update has several problems: It cannot prevent user's illegal update; it is hard to apply to the XML schemas stored in databases, needs much time to analyze schema, and is likely to make syntactic errors. In this paper, we propose an XML schema update facility, which enables creation, deletion and modification of XML schema by using commands.

• Journal of KIISE:Databases
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• v.36 no.2
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• pp.150-167
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• 2009

XML has become the new standard for storing, exchanging, and publishing of data over both the internet and the ubiquitous data stream environment. As demand for efficiency in handling XML document grows, labeling scheme has become an important topic in data storage. Recently proposed labeling schemes reflect the dynamic XML environment, which itself provides motivation for the discovery of an efficient labeling scheme. However, previous proposed labeling schemes have several problems: 1) An insertion of a new node into the XML document triggers re-labeling of pre-existing nodes. 2) They need larger memory space to store total label. etc. In this paper, we introduce a new labeling scheme called a Circle Labeling Scheme. In CLS, XML documents are represented in a circular form, and efficient storage of labels is supported by the use of concepts Rotation Number and Parent Circle/Child Circle. The concept of Radius is applied to support inclusion of new nodes at arbitrary positions in the tree. This eliminates the need for re-labeling existing nodes and the need to increase label length, and mitigates conflict with existing labels. A detailed experimental study demonstrates efficiency of CLS.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.801-802
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• 2009

Currently, XML and its schema language have become the standard for data representation and information exchange format on the current web. Unfortunately, problems happen when integrating different data sources since XML mainly supports the document structure but lack consideration on sharing knowledge of data. Meanwhile, Semantic Web technologies, such as Web Ontology Language (OWL), can include the structure as well as the semantics of the data. Therefore, finding a way to integrate XML data as OWL ontology receives a high interest nowadays. In this paper we present a mapping notation to convert XML Schema to OWL domain knowledge and an effective method to transform XML instances into OWL individuals. While keeping the XML original structure, our work also adds more semantics for the XML document. Moreover, whole of the transformation processes are done automatically without any user interference. Further, our transforming approach provides the solution for duplicate element names in XML document which has not mentioned in the previous work. Our results in existing OWL syntaxes can be loaded immediately by OWL editors and Semantic Web applications.

• Journal of Digital Contents Society
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• v.10 no.1
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• pp.129-145
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• 2009

As the secure distribution and sharing of information over the World Wide Web becomes increasingly important, the needs for flexible and efficient support of access control systems naturally arise. Since the eXtensible Markup Language (XML) is emerging as the de-facto standard format of the Internet era for storing and exchanging information, there have been recently, many proposals to extend the XML model to incorporate security aspects. To the lesser or greater extent, however, such proposals neglect the fact that the data for XML documents will most likely reside in relational databases, and consequently do not utilize various security models proposed for and implemented in relational databases. In this paper, we take a rather different approach. We explore how to support security models for XML documents by leveraging on techniques developed for relational databases considering object perspective. More specifically, in our approach, (1) Users make XML queries against the given XML view/schema, (2) Access controls for XML data are specified in the relational database, (3) Data are stored in relational databases, (4) Security check and query evaluation are also done in relational databases, and (5) Controlling access control is executed considering XML tree levels

• The KIPS Transactions:PartD
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• v.15D no.1
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• pp.1-14
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• 2008

This paper is on query processing in the mobile devices where memory capacity is limited. In case that a query against a large volume of XML data is processed in such a mobile device, techniques of fragmenting the XML data into chunks and of streaming and processing them are required. Such techniques make it possible to process queries without materializing the XML data in its entirety. The previous schemes such as XFrag[4], XFPro[5], XFLab[6] are not scalable with respect to the increase of the size of the XML data because they lack proper memory management capability. After some information on XML fragments necessary for query processing is stored, it is not deleted even after it becomes of no use. As such, when the XML fragments are dynamically generated and infinitely streamed, there could be no guarantee of normal completion of query processing. In this paper, we address scalability of query processing over dynamic XML fragment stream, proposing techniques of deleting information on XML fragments accumulated during query processing in order to extend the previous schemes. The performance experiments through implementation showed that our extended schemes considerably outperformed the previous ones in memory efficiency and scalability with respect to the size of the XML data.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.483-489
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• 2006

This study describes the XML -based digitalization of structural design sheets for exchange on the web. For this purpose the data model of the XML document that represents the structural design sheets for buildings, including mathematical expressions and graphics that cannot be easily exchanged on the web, is defined. Then, the prototype that facilitates the web-based exchange of the XML documents is developed and the feasibility of the results of this study is discussed.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.563-573
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• 2006

Cyber-infrastructures for scientific and engineering applications require integrating heterogeneous legacy data in different formats and from various domains. Such data integration raises challenging issues: (1) Support for multiple independently-managed schemas, (2) Ease of schema evolution, and (3) Simple schema mappings. In order to address these issues, we propose a novel approach to semantic integration of scientific data which uses XML schemas and RDF-based schema mappings. In this approach, XML schema al-lows scientists to manage data models intuitively and to use commodity XML DBMS tools. A simple RDF-based ontological representation scheme is used for only structural relations among independently-managed XML schemas from different institutes or domains We present the design and implementation of a prototype system developed for the national cyber-environments for civil engi-neering research activities in Korea (similar to the NEES project in USA) which is called KOCEDgrid (http://www.koced.net).

• Journal of KIISE:Databases
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• v.36 no.3
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• pp.180-188
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• 2009

Recently, the needs for an efficient and secure access control method of dynamic XML data in a ubiquitous data streams environment have become an active research area. In this paper, we proposed an improved role-based prime number labeling scheme for an efficient and secure access control labeling method in dynamic XML data streams. And we point out the limitations of existing access control and labeling schemes for XML data assuming that documents are frequently updated. The improved labeling method where labels are encoded ancestor-descendant and sibling relationships between nodes but need not to be regenerated when the document is updated. Our improved role-based prime number labeling scheme supports an infinite number of updates and guarantees the arbitrary nodes insertion at arbitrary position of the XML tree without label collisions. Also we implemented an efficient access control using a role-based prime number labeling. Finally, we have shown that our approach is an efficient and secure through experiments.

• Journal of KIISE:Databases
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• v.31 no.1
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• pp.72-81
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• 2004

Theses days, a number of data over the Internet are represented using XML because of a virtue of XML. In proportion to the increase of XML data, query processing techniques are required that support quickly and efficiently the diverse queries to search the useful information on XML documents. But, up to now, the researches handling queries for XML data are methodologies focusing on how to process regular path expressions. Therefore, we have developed a new genealogy-based indexing technique to solve various queries such as not only regular path expression but also simple path expression, path expression referencing other elements, and so on. Also, we have applied this technique on object-relational model and evaluated the performance for many documents and various query types. The result shows improved performance in comparison with the other storage techniques.

• Journal of Computing Science and Engineering
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• v.4 no.4
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• pp.313-349
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• 2010

In this paper, we study the data interoperability problem of web services in terms of XML schema compatibility. When Web Service A sends XML messages to Web Service B, A is interoperable with B if B can accept all messages from A. That is, the XML schema R for B to receive XML instances must be compatible with the XML schema S for A to send XML instances, Le., A is a subschema of B. We propose a formal model called Schema Automaton (SA) to model W3C XML Schema (XSD) and develop several algorithms to perform different XML schema computations. The computations include schema minimization, schema equivalence testing, subschema testing, and subschema extraction. We have conducted experiments on an e-commerce standard XSD called xCBL to demonstrate the practicality of our algorithms. One experiment has refuted the claim that the xCBL 3.5 XSD is backward compatible with the xCBL 3.0 XSD. Another experiment has shown that the xCBL XSDs can be effectively trimmed into small subschemas for specific applications, which has significantly reduced the schema processing time.