• 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.

• Journal of KIISE:Databases
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• v.29 no.6
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• pp.417-428
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• 2002

XML(extensible Markup Language) is effective to information retrieval and sharing but has defects related to the data security. And, as a solution of this problem, the current XML security researches such as XML digital signature, XML data encryption, and XML access control exclude the validation property of XML document. The validation of XML should be considered for the secure information sharing in the XML-based environment. In this paper, we design and implement the system to support both security and validation to XML document. Our system performs data encryption and maintenance of valid status of XML document by referencing new XML schema namespace. In addition, it also provides the XML schema security function through the XML schema digital signature. During generating XML schema digital signature, DOMHash method which has the advantage of the faster speed than canonical XML method is applied to XML schema. In conclusion, our system shows the improved functions in flexibility, scalability, and reliability compared with the existing XML security researches.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.5
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• pp.972-977
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• 2003

XML has weakness problems on document modulation and elimination of data Because of the XML gives priority to present data format, XML signature, XML encryption, or XML access control is provided to overcome those weakness problems. However, structured XML efficiency contravention problem occurred from XML encryption and absence of protection from DID attack are still remains unsolved. In this paper, we suggests the XML schema that satisfies both validity and encryption. The DTD is unnecessary because XML schema supports Well-Formed XML documents and include meta information. Also XML schema has possibility to generate each XML document dynamically and because of self efficiency investigator rule, it has an advantage on extendability of DID based encryption of XML documents.

• Journal of KIISE:Databases
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• v.34 no.2
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• pp.153-165
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• 2007

XML is widely used in various applications as the standard for representing and exchanging data on the Web. XML Schema is the standard schema for XML and an XML document generated based on the XML Schema is called 'Valid XML document'. The XML Schema validity should be guaranteed after the XML document is updated. In this paper, we design an efficient method that verifies XML Schema validity before update, and so eliminates unnecessary validations. Also, we propose validation algorithms for each update. In addition, we propose the mapping between XML data and XML Schema and a storage method for XML Schema in order to efficiently extract the schema information for the validation. Finally, we compare the performance of the validation according to the storage methods.

• Journal of the Korea Society of Computer and Information
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• v.9 no.4 s.32
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• pp.19-26
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• 2004

XML DTD is defining expression of simple form for XML document, there is much difficulties to define structure of XML document. Solving XML DTD's problem, W3C was select XML schema by standard in 2001. This paper proposes a design to XML DBMS using Relational Database based on XML schema to be selected by standard from W3C to overcome XML DBMS's shortcoming using XML DTD.

• The KIPS Transactions:PartD
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• v.13D no.5 s.108
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• pp.641-650
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• 2006

XML has the characteristics of self-describing and uses DTD or XML schema in order to constraint its structure. Even though the XML schema is only at the stage of recommendation yet, it will be prevalently used because DTD is not itself XML and has the limitation on the expression power. The structure defined by the XML schema as well as the data of the XML documents can vary due to complex reasons. Those reasons are errors in the XML schema design, new requirements due to new applications, etc. Thus, we propose XML schema evolution operators that are extracted from the analysis of the XML schema updates. These schema evolution operators enable the XML schema updates that would have been impossible without supporting tools if there are a large number of XML documents complying the U schema. In addition, these operators includes the function of automatically finding the update place in the XML documents which are registered to the XSE system, and maintaining the XML documents valid to the XML schema rather than merely well-formed. This paper is the first attempt to update XML schemas of the XML documents and provides the comprehensive set of schema updating operations. Our work is necessary for the XML application development and maintenance in that it helps to update the structure of the XML documents as well as the data in the easy and precise manner.

• Journal of KIISE:Databases
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• v.30 no.3
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• pp.252-272
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• 2003

The view mechanism provides users with appropriate portions of database through data filtering and integration. In the Web era where information proliferates, the view concept is also useful for XML, a future standard for data exchange on the Web. This paper proposes a method of implementing XML views called XML view indexing, whereby XML view xv is represented as an XML view index(XVI) which is a structure containing the identifiers of xv's underlying XML elements as well as the information on xv. Since XVI for xv stores just the identifiers of the XML elements but not the elements themselves, when a user requests to retrieve xv, its XVI should be materialized against xv's underlying XML documents. Also an efficient algorithm to incrementally maintain consistency of XVI given a update of xv's underlying XML documents is required. This paper proposes and implements data structures and algorithms for XML view indexing. The performance experiments on XML view indexing reveal that it outperforms view recomputation for repeated accesses to the view, and requires as much as about 30 times less storage space compared to XML view materialization though the latter takes less time for repeated accesses to the view due to no need of materialization.

• The KIPS Transactions:PartA
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• v.11A no.2
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• pp.149-158
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• 2004

XML as a standard for representing data and document structure is widely used in every area, and we have to write XML compilers which process the XML documents according to a user's intention. Because it takes time and costs to write XML compilers by hand, we need some generators that automatically generate XML compilers. In this paper, we introduce an XML compiler generator named XCC. It reads DTD and semantic rules, and it generates XML compiler and Java classes which correspond to the elements defined in the DTD.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.513-518
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• 2003

Established XML at February, 1998 in W3C by solution about document processing and exchange and reusability to be shortcoming that early web happens using nonstructural document. Existing electron transaction is changing in electronic business form between corporation through XML base message exchange using XML. Necessity about solution that can masticate structured electron transaction of XML base that is used in electron transaction between corporation rose. Structured electron transaction of XML base that is used in electron transaction in treatise that see hereupon efficiently study about XML document editing system that integrate XML Schema editor to masticate XML Schema document that define edit and XML instance editor of user central that can write a book and structure of XML document efficiently do.

• The KIPS Transactions:PartD
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• v.10D no.4
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• pp.603-612
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• 2003

According to development of Web, an amount of XML documents has been increasing. So, many researches are proceeding to verify XML data coming from clients and to store or query efficiently database. In order to verify, store and query, DTD or XML Schema of XML documents is necessary. However, Schemaless XML documents couldn't be operated since they do not have either DTD or in Schema. In this paper, we extract XML schema in order to verify XML data and store or query efficiently database from either well-formed XML or XML Schemaless documents. XML Schema extracting technique which is proposed in this paper extract Schema graph using simulation and dataguide that is a extracting technique for semistructured characteristics of XML data. Also, we propose extracting technique for XML Schema using pattern tables that are considerated with Schema graph and reusability.