• Journal of the Korean Society for information Management
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• v.19 no.4
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• pp.298-319
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• 2002

The Semantic Web is a new technology that attempts to achieve effective retrieval, automation, integration, and reuse of web resources by constructing knowledge bases that are composed of machine-readable definitions and associations of resources that express the relationships among them. To have this kind of Semantic Web in place, it is necessary to have the following infrastructures: capability to assign unchangeable and unique identifier (URI) to each resource, adoption of XML namespace concept to prevent collision of element and attribute names defined by various institutions, widespread use of RDF to describe resources so that diverse metadata can be interoperable, use of RDF schema to define the meaning of metadata elements and the relationships among them, adoption of DAML+OIL that is built upon RDF(S) to increase reasoning capability and expressive power, and finally adoption of OWL that is built upon DAML+OIL by removing unnecessary constructors and adding new ones based on experience of using DAML+OIL. The purpose of this study is to describe the central concepts and technologies related to the Semantic Web and to discuss the benefits of metadata interoperability based on XML/RDF schemas and the potential applications of diverse ontologies.

• Proceedings of the Korean Society for Information Management Conference
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• 1998.08a
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• pp.193-196
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• 1998

웹 상에 존재하는 상이한 메타데이터들간의 상호호환성을 위해서는 각각의 메타데이터 형식에서 지정하고 있는 다양한 어의, 구조, 구문을 모두 수용할 수 있는 통합된 구조가 필요하다. 본고에서는 이를 위한 방안으로써 개념적 체계를 제시한 워릭구조와 이의 영향을 받아 W3C에서 제안한 RDF를 중심으로 고찰하며, 더블린코어를 RDF로 구현하고자 하는 방안을 모색하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.84-87
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• 2014

상황인지는 유비쿼터스 컴퓨팅 환경에서 사용자의 주변 상황을 인지하여 사용자가 원하는 서비스를 제공하기 위해 필요한 핵심 기술이다. 이러한 상황인지를 위해 여러 센서로부터 발생하는 저수준의 컨텍스트 정보를 처리하는 다양한 방법들이 존재한다. 그러나 현재 상황인지 처리에 관련된 표준 방법이 없어 서비스 도메인에 제한되고 복잡한 구현방법을 따라야 하며, 상황정보를 처리하는 시스템에 정형화된 상황정보를 제공하는데 어려움이 있다. 이에 본 논문에서는 정형화된 상황정보를 제공하기 위한 센터 데이터 변환 방법을 제안한다. 제안하는 센서 데이터의 변환 방법은 센서로부터 발생하는 저수준의 컨텍스트를 RDF 기반의 고수준의 상황정보로 변환하며, 변환된 정보는 상황인지 시스템에 제공된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2004.05a
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• pp.531-534
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• 2004

인터넷에 있는 많은 응용프로그램들의 용도와 부가적인 정보를 아는 것은 매우 어렵다. 웹에는 수많은 정보들이 존재하고 이것들을 필요에 따라 정확하게 검색하는 것이 점점 어려워지고 있다. 이러한 어려움을 해결하기 위해 현재 메타데이터를 사용하여 웹 자원을 검색하는 연구가 활발하게 진행되고 있다. W3C는 메타데이터의 상호운용성과 통합을 위한 환경으로 RDF(Resource Description Framework)를 표준으로 정했다. 본 논문에서는 응용프로그램이나 프로그램 개발에 필요한 작은 단위의 프로그램에 대해 RDF를 이용하여 메타데이터로 만들고 이것을 대상으로 검색 가능하도록 하여 사용자가 원하는 정보를 보다 정확한 검색을 수행할 수 있도록 하였다.

• KIISE Transactions on Computing Practices
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• v.23 no.5
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• pp.275-283
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• 2017

A large amount of RDF data has been generated along with the increase of semantic web services. Various distributed storage and query processing schemes have been studied to efficiently use the massive amounts of RDF data. In this paper, we propose a distributed SPARQL query processing scheme that considers the data locality and query execution path of large RDF data. The proposed scheme considers the data locality and query execution path in order to reduce join and communication costs. In a distributed environment, when processing a SPARQL query, it is divided into several sub-queries according to the conditions of the WHERE clause by considering the data locality. The proposed scheme reduces data communication costs by grouping and processing the sub-queries through the index based on associated nodes. In addition, in order to reduce unnecessary joins and latency when processing the query, it creates an efficient query execution path considering data parsing cost, the amount of each node's data communication, and latency. It is shown through various performance evaluations that the proposed scheme outperforms the existing scheme.

• Journal of Korean Library and Information Science Society
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• v.36 no.3
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• pp.109-136
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• 2005

This paper describes the major components of ISO/IEC 11179 metadata registry (MDR) standard designed to promote data interoperability between systems, explains and discusses semantic web technology and Web ontology languages initiated by W3C that can be employed to further enhance data interoperability, and finally proposes a framework for a new RDF/OWL-based MDR to convert from the current human-readable MDR to machine-readable MDR. If the new MDR is successful, we might be able to offer a better customized information service to users. The future research will be concerned with evaluating objectively the effectiveness of machine-readable MDR in meeting the needs of real users.

• The Journal of the Korea Contents Association
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• v.15 no.1
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• pp.9-23
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• 2015

In this paper, we propose a new RDF index scheme considering the characteristics of large scale RDF data to improve the query processing performance. The proposed index scheme creates a S-O index for subjects and objects since the subjects and objects of RDF triples are used redundantly. In order to reduce the total size of the index, it constructs a P index for the relatively small number of predicates in RDF triples separately. If a query contains the predicate, we first searches the P index since its size is relatively smaller compared to the S-O index. Otherwise, we first searches the S-O index. It is shown through performance evaluation that the proposed scheme outperforms the existing scheme in terms of the query processing time.

• The KIPS Transactions:PartB
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• v.11B no.5
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• pp.573-580
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• 2004

As the modern techniques have improved, people intend to store and manage the information on the web. Especially, it is the image data that is given a great deal of weight of the information because of the development of the scan and popularization of the digital camera and the cell-phone's camera. However, most image retrieval systems are still based on the text annotations while many images are creating everyday on the web. In this paper, we suggest the new approach for the semantic image retrieval using the RDF metadata based on the representation of the spatial relationships. For the semantic image retrieval, firstly we define the new vocabularies to represent the spatial relationships between the objects in the image. Secondly, we write the metadata about the image using RDF and new vocabularies. Finally. we could expect more correct result in our image retrieval system.

• Journal of KIISE:Databases
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• v.33 no.5
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• pp.476-485
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• 2006

The Resource Description Framework(RDF), which emerged with the semantic web, is settling down as a standard for representing information about the resources in the World Wide Web Hence, a lot of research on storing and query processing RDF documents has been done and several RDF storage systems, such as Sesame and Jena, have been developed. But the research on updating RDF documents is still insufficient. When a RDF document is changed, data in the RDF triple store also needs to be updated. However, current RDF triple stores don't support incremental update. So updating can be peformed only by deleting the old version and then storing the new document. This updating method is very inefficient because RDF documents are steadily updated. Furthermore, it makes worse when several RDF documents are stored in the same database. In this paper, we propose an incremental update algorithm on RDF, documents in triple stores. We use a text matching technique for two versions of a RDF document and compensate for the text matching result to find the right target triples to be updated. We show that our approach efficiently update RDF documents through experiments with real-life RDF datasets.

• 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.