• Journal of the Korea Society of Computer and Information
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• v.16 no.3
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• pp.89-97
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• 2011

In semantic web information system like ontology that access distributed information from network, efficient query processing requires an advanced caching mechanism to reduce the query response time. P2P network system have become an important infra structure in web environment. In P2P network system, when the query is initiated, reducing the demand of data transformation to source peer is important aspect of efficient query processing. Caching of query and query result takes a particular advantage by adding or removing a query term. Many of the answers may already be cached and can be delivered to the user right away. In web environment, semantic caching method has been proposed which manages the cache as a collection of semantic regions. In this paper, we propose the semantic caching technique in cluster environment of peers. Especially, using schema data filtering technique and schema similarity cache replacement method, we enhanced the query processing efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.921-929
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• 2008

Recently, many researches have been conducted to solve data heterogeneity as a way for data integration. The elements of the system that we suggest are an XMDR wrapper and XMDR Repository. XMDR wrapper solves the heterogeneity of the existing system by creating the interface based on the standard information of XMDR, and performing the inter-conversion between global XMDR query and local query using mapping data on standard information and local schema. XMDR Repository are composed of XMDR which manages the mapping data on standard information and local schema, and of Proxy DB which saves the accomplished results. With XMDR wrapper and XMDR Repository, users can use the same interface, and they need not conduct repeated queries since XMDR wrapper not only solves the heterogeneity of the schema using the meta-semantic ontology of XMDR, but also considers the heterogeneity accompanying the meaning of the value through instance semantic ontology. Therefore, in this paper we suggest the grid wrapper for the solution of data heterogeneity and efficient data integration.

• Journal of the Korean Institute of Intelligent Systems
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• v.27 no.1
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• pp.42-49
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• 2017

Studies for efficient information retrieval and reuse of information resources using the ontology techniques are being in progress in various fields. In this paper, we build an ontology to provide a food additive information for consumers given by the KFDA and food safety information portal. Food additives were represented in OWL based knowledge using $Prot{\acute{e}}g{\acute{e}}$. We defined Class, Property, Relationships for providing food additives names, origins, purposes and basic information. In order to retrieve the information of the food additive, we built 679 instances with an ontology, and confirmed the results through DL Query queries. We can expect that the food additives ontology shown in this paper will help the integration and improvement of the information retrieval systems of the related fields in future.

• Journal of the Korea Society of Computer and Information
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• v.12 no.5
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• pp.93-102
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• 2007

Metadata and ontology can be used to retrieve related information through the inference mure accurately and simply on the Semantic Web. RDF and RDF Schema are general languages for representing metadata and ontology. An enormous number of keywords on the Semantic Web are very important to make practical applications of the Semantic Web because most users prefer to search with keywords. In this paper, we consider a resource as a unit of query results. And we classily queries with keyword conditions into three patterns and propose indexing techniques for keyword-search considering both metadata and ontology. Our index maintains resources that contain keywords indirectly using conceptual relationships between resources as well as resources that contain keywords directly. So, if user wants to search resources that contain a certain keyword, all resources are retrieved using our keyword index. We propose a structure of table for storing RDF Schema information that is labeled using some simple methods.

• The Journal of Society for e-Business Studies
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• v.14 no.1
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• pp.81-92
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• 2009

In order to use a RDBMS as the repository for product information, it is essential that the ontological query be processed effectively and answered properly, satisfying the user's expectations for an ontological query process. To be well-processed ontological queries, the key point is whether the various semantic relationships among the concepts of the product information are likewise well-processed. For feasibly processing a semantic query, we need to consider how the product ontology data is designed and stored in RDBMS. In this paper, we present how a RDB schema for the product ontology could be designed and queried.

• Journal of the Korean Society for Library and Information Science
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• v.41 no.2
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• pp.291-316
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• 2007

The purpose of this study is to design metadata model for describing different kinds of concepts, properties, and semantic relationships of result materials of researches. We examine our metadata model to evaluate correctness and efficiency of the model through contents analysis of a constructed database. From the results of examination, we suggest more effective structure of metadata schema. Domain ontology could constructed by the enlarged thesaurus in order to overcome the limitation of the keyword search, therefore we design a philosophy and religion ontology based on subject classification to improve information retrieval and implement it using XML/Topic Maps to improve retrieval functionality of our database.

• Proceedings of the Korea Society for Simulation Conference
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• 2005.11a
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• pp.180-184
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• 2005

These days, home network connects all home appliances using one of broadband convergence network, is constructed and propagated to more than 10 million house hold. Users can monitor and control statuses of home appliances using mobile terminal through homeserver. For active propagation of home network, high-quality multimedia service is very important. Specially, as digital recorder and digital camera is propagated, new paradigm that private DVDs can be shared in many household shows up. The homeserver is the main part of UbiHome, which can store much multimedia content and through which the user can search and share these contents. For searching and sharing, the metadata of contents is supposed to keep the consistency. These metadata include the description to different format such as Image, movie, and music. Therefore, we intend to provide a RDF model for effectively storing, searching and managing high-quality contents in UbiHome. In this paper, we propose to make Ontology to close semantic approach using RDF/RDF Schema for managing multimedia data in UbiHome. we propose RDF-Based Local Ontology and merging these ontology to RDF-Based Global Ontology.

• Journal of Digital Convergence
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• v.10 no.7
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• pp.179-184
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• 2012

The ultimate purpose of cities is 'the enhancement of quality of life in city'. In order to achieve this, it is required to optimize the Ontology-driven ubiquitous services included in the U-City and UIS of regions and communities and so on. Almost U-Service's contents are related to spatial or temporal extent. So it is important to design Spatio-temporal event schema for efficient access to U-City. There is a rapid change into an urban society in the shape of Ontology-driven ubiquitous services in which a content on a region or an incident is newly reconstructed through various ideas with the influence of the ubiquitous environment.

• Journal of Korea Multimedia Society
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• v.7 no.9
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• pp.1195-1207
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• 2004

Schema matching is prerequisite to an automated transformation of XML documents. Because previous works about schema matching compute all semantically-possible matchings, they produce many-to-many matching relationships. Such imprecise matchings are inappropriate for an automated transformation of XML documents. This paper presents an efficient schema matching algorithm that computes precise one-to-one matchings between two schemas. The proposed algorithm consists of two steps: preliminary matching relationships between leaf nodes in the two schemas are computed and one-to-one matchings are finally extracted based on a proposed path similarity. Specifically, for a sophisticated schema matching, the proposed algorithm is based on a domain ontology as well as a lexical database that includes abbreviations and synonyms. Experimental results with real schemas from an e-commerce field show that the proposed method is superior to previous works, resulting in an accuracy of 97% in average.

• Journal of KIISE:Databases
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• v.35 no.2
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• pp.155-168
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• 2008

This paper proposes a relational security model-based RDF Web ontology access control model. The Semantic Web is recognized as a next generation Web and RDF is a Web ontology description language to realize the Semantic Web. Much effort has been on the RDF and most research has been focused on the editor, storage, and inference engine. However, little attention has been given to the security issue, which is one of the most important requirements for information systems. Even though several researches on the RDF ontology security have been proposed, they have overhead to load all relevant data to memory and neglect the situation that most ontology storages are being developed based on relational database. This paper proposes a novel RDF Web ontology security model based on relational database to resolve the issues. The proposed security model provides high practicality and usability, and also we can easily make it stable owing to the stability of the relational database security model.