• The KIPS Transactions:PartD
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• v.8D no.6
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• pp.799-812
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• 2001

As XML become more popular for encoding data and exchanging format on the web, recent work on processing XML Document in DBMS has been performed. However, there is no formal data model for XML, and there is lack of research on XML algebra for processing complex XML query and even the mediators have many restrictions. Therefore, this paper proposes formal data model and algebra based on directed edge labeled graph for XML query. To implement algebra, not only algorithms of operation for algebra are presented, but also they are implemented using access method and path index based on RDBMS or ORDBMS. In particular, experiments to show the effectiveness of the implemented algebra are performed on XML documents on EST data which are semistructured data.

• The KIPS Transactions:PartD
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• v.10D no.3
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• pp.387-398
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• 2003

Materialized views have received much attention for query performance improvement. They need to be refreshed whenever their underlying data sources are updated. They could be recomputed from scratch or they could be incrementally refreshed by reflecting only those portions of updates that affect them. With emergence of XML as the standard for data exchange on the Web, active research is under way on effectively storing and retrieving XML documents. In this paper, we describe a performance study on the incremental refresh of XML materialized views for the case where XML documents are stored in a relational DBMS, and XML materialized views are maintained with incremental refresh. We describe implementation of a prototype XML storage system that supports XML materialized views and their incremental refresh, and report the performance results obtained with the implemented system through a detailed set of experiments on the incremental refresh of XML materialized views. The results show that the XML view maintenance with incremental refresh outperforms the ordinary view recomputation.

• International Journal of Contents
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• v.3 no.3
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• pp.6-14
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• 2007

In this paper, we design and implement a XML Repository System(XRS) that exploits the advantages of DBMSs and IRSs. Our scheme uses BRS to support full text indexing and content-based queries efficiently, and ORACLE to store XML documents, multimedia data, DTD and structure information. We design databases to manage XML documents including audio, video, images as well as text. We employ the non-composition model when storing XML documents into ORACLE. We represent structured information as ETID(Element Type Id), SORD(Sibling ORDer) and SSORD(Same Sibling ORDer). ETID is a unique value assigned to each element of DTD. SORD and SSORD represent an order information between sibling nodes and an order information among the sibling nodes with the same element respectively. In order to show superiority of our XRS, we perform various experiments in terms of the document loading time, document extracting time and contents retrieval time. It is shown through experiments that our XRS outperforms the existing XML document management systems. We also show that it supports various types of queries through performance experiments.

• Journal of Internet Computing and Services
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• v.3 no.1
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• pp.29-40
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• 2002

The information exchange on the using of XML such as B2B electronic is common. So the efficient method to store XML message in database is needed. Because the ORDBMS is extended to ORDBMS for supporting multimedia application such as Oracle8i, 9i, Informix and SQL2000 server, SQL2, the standard RDB is extended to SQL3 for ORDB, And the XML application based on java such as J2EE is extended. Therefor it is necessary for the efficient connection methods based on JDBC between XML application and database system. In this paper, the methodology a transformation XML DTD to SQL3 schema is proposed. For the transformation, first the methods of transformation XML DTD to object model in UML class diagram are proposed. And then the methods of mapping transferred object models to SQL3 schema are proposed. This approach for transform::1lion XML. DTD to SQL3 schema such as Oracle8i, 9i, Informix and SQL2000 server based on java is proposed in this paper, can be used in database design to build XML applications based on ORDB.

• Journal of KIISE:Databases
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• v.29 no.2
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• pp.89-98
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• 2002

As XML has become an emerging standard for information exchange on the World Wide Web it has gained attention in database communities to extract information from XML seen as a database model. Recently, many researchers have addressed the problem of storing XML data and processing XML queries using traditional database engines. Here, most of them have used relational database systems. In this paper, we show that OODBSs can be another solution. Our technique generates an OODB schema from DTDs and processes XML queries, Especially, we show that the semi-structural part of XML data can be represented by the 'inheritance' and that this can be used to improve query processing.

• Journal of the Korean Society for information Management
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• v.21 no.2
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• pp.189-210
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• 2004

The purpose of this study is to evaluate the performance of XML retrieval based on ORDBMSs(Object-Relational Database Management Systems) approach. This paper describes indexing and retrieval methods for XML documents and the methodologies of experiments at INEX(Initiative for the Evaluation of XML retrieval). Like any other traditional information retrieval experiment, the test collection was consists of documents, topics/queries, task, relevance assessments and evaluation. EXIMA$^{TM}$ Supply, a kind of native XML DB based on ORDBMS technologies, is used for this experiment. Although this approach has many benefits, for example, no delay in storing and searching XML documents. but it showed relatively disappointed retrieval performance at INEX 2002. This result may caused since the given topics had to be decomposed and modified to be processed by the XPath processor, and during this modification the original meaning of topics can be changed inevitably and some important information nay pass over.r.

• The KIPS Transactions:PartD
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• v.13D no.1 s.104
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• pp.1-10
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• 2006

This paper introduces the development XPERT(XML Query Processing Engine using Relational Technologies) which is based on relational model. In our system we have used a decomposed approach to store XML files in relational tables. XML queries are translated to SQLs according to the table schema, and then they are sent to the relational DBMS to get the results back. Our translation scheme produces AST(Abstract Syntax Tree) by analyzing XQuery expressions at first. And on traversing AST proper SQLs are generated. Translated SQLs can reduce the number of joins by using path information and utilize dewey number to preserve document originated orderings among compoments in XML. In addition we propose the efficient algorithms of XPath and XQuery translation. And finally we show the implementation of our prototype system for the functional evaluations.

• 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).

• The Journal of Society for e-Business Studies
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• v.15 no.4
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• pp.1-19
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• 2010

Recently, it is necessary to process real time sensor data, which is generated from ubiquitous environments. Data, which are written by XML, are small, but, large volumes of data. Therefore, weneed to use an efficient method for processing a large amount of it. An XQuery has two types for sensor data: one is to get sensor identification and value from sensor data; the other is restructuring for user's convenience. Existing XQuery engines don't have efficient method for batch processing of sensor data. This paper proposed the twig query processing over reverse path summary, and we developed and applied restructuring batch processing method for real time processing of a large amount of sensor data. Finally, we do performance evaluation using XMark and RFID EPC data, and comparison analysis with MonetDB/XQuery and Berkeley DB XML.

• Spatial Information Research
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• v.18 no.4
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• pp.65-73
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• 2010

Recently, the importance of the ocean has been increasing internationally as the new source for mineral resources following the exhausted land resources that arc becoming scarce. On a long-term aspect, growth of nations by gaining competitiveness on marine resources was considered a paradigm. Because dominating the development right of marine resources came up as the main concern. South Korea has also been interested in marine resources and this is the reason why massive amounts of marine exploration data arc annually created through surveying and drilling around the Korean Peninsula. but the data has not been systematically managed very well because of its economic costs. Therefore, this research is mainly focused on systematical data managing methods. For Systematical data management. the exploration data is integrated and organized by using XML tables. This can be a systematical data management. because the methods release dependency between data and system, and it also enables to update existing data and renew the data. In the future, the constructed database from this study could definitely contribute to enhancing data management. As well, the developed system in this research can provide various spatial analysis and searching techniques to enable easier data provision of various exploration areas. Furthermore. this will be very useful to extend functions of the system and to adopt other types of DBMS. In addition, the spatial analysis and search function of location based service can be utilized through GIS. and it can support sustainable and systematic management in a long term.