• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.217-219
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• 2005

정보의 단순한 연결을 표현하는 현재 웹 환경의 한계를 보완하기 위해 차세대 웹으로서 평가되고 있는 시맨틱 웹에서는 정보 리소스의 의미와 개념적 관계를 정의하는 메타데이터와 온톨로지의 역할이 무엇보다 중요시되고 있다. 따라서 RDF와 RDF 스키마와 같은 표준 언어로써 표현되는 메타데이터와 온톨로지의 효과적인 저장과 검색의 방법이 필요하다. RDF와 RDF 스키마는 그래프 모델로서 표현이 가능하고 다양한 질의의 형태가 그래프 형태에서 추출 가능한 경로 형식으로 표현들 수 있기 때문에 보다 효율적인 질의 처리를 위해서는 경로 정보의 저장에 대한 연구가 필요하다. 따라서 본 논문에서는 관계형 데이터베이스를 기반으로 RDF와 RDF 스키마의 기본적인 정보와 특정 클래스, 프로퍼티, 리소스로 시작하는 경로 정보를 함께 저장할 수 있는 저장 구조를 제안한다.

• Journal of KIISE:Databases
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• v.35 no.2
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• pp.132-142
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• 2008

In biological domain, there exist a variety of protein analysis databases which have their own meaning toward the same target of protein. If we integrate these scattered heterogeneous data efficiently, we can obtain useful information which otherwise cannot be found from each original source. Reflecting the characteristics of biological data, each data source has its own syntax and semantics. If we describe these data through RDF(S) models, one of the Semantic Web standards, we can achieve not only syntactic but also semantic integration. In this paper, we propose a new concept of integration layer based on the RDF unified schema. As a conceptual model, we construct a unified schema focusing on the protein information; as a representational model, we propose a technique for the wrappers to aggregate necessary information from the relevant sources and dynamically generate RDF instances. Two example queries show that our integration layer succeeds in processing the integrated requests from users and displaying the appropriate results.

• Journal of the Korea Computer Industry Society
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• v.7 no.3
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• pp.227-236
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• 2006

Semantic Web is getting popular to next web environment. Additionally, ontology language research is also activating to represent semantic relation of resource in semantic web. Specially, Ontology language as RDF and DAML+OIL appear on start point of research. But Ontology Language limited to describing characters of resource and to making a clear definition of relation of resource. So W3C suggest OWL at the next standard language for describing resource. OWL supply the lack of representation for RDF and RDF Schema. In this paper, we make Ontology to implement Online Retrieval System using OWL and propose the structure of storing Ontology document at the RDB. The structure support characters of OWL that are equivalent relationship, heterogeneous relationship, inverse relationship, union relationship and one of relationship between classes or properties. In this paper, we classify the extended elements for OWL from RDF Schema. And we propose the method of storing OWL using RDB for interoperability with many applications based on RDB. Finally, implement the storage and retrieval system based on OWL to provide advanced search function.

• Journal of Intelligence and Information Systems
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• v.11 no.2
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• pp.31-45
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• 2005

In this paper, convert in RDF triple and a RDF document through RDF document converters and design metadata schema about a digital camcorder after use Wrapper technology, and acquiring commodity information of a HTML page about the digital camcorder which these papers are defined so as to be different by electronic commerce stores, and is expressed. Save in digital camcorder domain ontology storage that implemented to relational database to DCC knowledge base ontology as convert to OWL Web ontology based on designed metadata schema. Through compare with rdf and DCCKBO, mapping, and inference process, provide to buyers by DCC information of the store that had the commodity purchasing information which is the best, and proposed a dynamic Web ontology guessed to contents of the best commodity purchasing information, and to define domain ontology saved in DCCKBO.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.1
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• pp.19-30
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• 2014

For the expansion of the Semantic Web, studies in converting the data stored in the relational database into the ontology are actively in process. Such studies mainly use an RDB to RDF mapping model, the model to map relational database components to RDF components. However, pre-proposed mapping models have got different expression modes and these damage the accessibility and reusability of the users. As a consequence, the necessity of the standardized mapping language was raised and the W3C suggested the R2RML as the standard mapping language for the RDB to RDF model. The R2RML has a characteristic that converts only the relational database schema data to RDF. For the same reasons above, the ontology about the relation data between table name and column name of the relational database cannot be added. In this paper, we propose an RDB to RDF mapping system considering semantic relations of RDB components in order to solve the above issue. The proposed system generates the mapping data by adding the RDFS attribute data into the schema data defined by the R2RML in the relational database. This mapping data converts the data stored in the relational database into RDF which includes the RDFS attribute data. In this paper, we implement the proposed system as a Java-based prototype, perform the experiment which converts the data stored in the relational database into RDF for the comparison evaluation purpose and compare the results against D2RQ, RDBToOnto and Morph. The proposed system expresses semantic relations which has richer converted ontology than any other studies and shows the best performance in data conversion time.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.82-84
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• 2005

시맨틱 웹의 등장에 따라 RDF와 RDF Schema(RDF/RDFS)로 표현되는 웹 데이타의 양이 증가하고 있다. 이에 웹 데이타를 효율적으로 저장, 검색할 수 있는 인덱스 구조의 필요성이 높아지고 있다. 본 연구에서는 기존의 트리 모델을 위한 소수 레이블 기법(prime number labeling scheme)을 발전시켜, RDF/RDFS 인덱스 구조를 표현할 수 있는 그래프 모델을 위한 소수 레이블 기법을 제안한다. 제안한 기법은 기존의 소수 레이블 기법을 그래프에 적용하여 구조 질의(Structural Query)를 효율적으로 처리할 수 있고, 데이타 갱신 시에 인덱스를 재구성하지 않아도 되는 장점을 가지고 있다. 그리고 이전의 RDF/RDFS 인덱스 구조에서 효율적으로 처리하기 힘들었던 순환 방향성 그래프에 대한 질의도 쉴게 처리할 수 있다.

• Journal of the Korean Society for information Management
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• v.18 no.4
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• pp.15-35
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• 2001

This paper suggests metadata as an effective search tool suitable for moving images on the web. Dublin Core, a leading metagata sceme of web resources, and MPEG-7, a coming international standard developed by MPEG, are used to construct a hybrid metadata scheme. RDF is selected as a framework for a matadata description and Moving Image Core was developed as a RDF schema. Finally, RDF/XML encoded metadata of moving images are retrieved throuth web-based database system using ASP technology.

• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.10a
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• pp.623-625
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• 2003

The Semantic Web stands out in the next generation web, recently. In the Semantic Web, any information resources is defined by semantics and semantic links is given among these. It is different from existing web service environment. RDF (Resource Description Framework) is the data model to describe metadata of web resource and is to support for semantic links. And it is much the same as WSDL (Web Serice Description Language). In theis paper, we propose the RDF design method to improve the search performance by integrating RDF data unit with WSDL. We confirm the performance and efficiency of search will be improved by using the proposed method.

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.67-80
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• 2022

In this paper, we propose a system which automatically generates the ShEx schemas to describe and validate RDF knowledge graphs constructed by RML mapping. ShEx schemas consist of constraints. The proposed system generates most of the constraints by converting the RML mapping rules. The schemas consisting only of constraints obtained from mapping rules can help users to figure out the structure of the graphs generated by RML mapping, but they are not sufficient for sophisticated validation purposes. For users who need a schema for validation, the proposed system is also able to provide the schema with added constraints generated from metadata extracted from the input data sources for RML mapping. The proposed system has the ability to handle CSV, XML, JSON or RDBMS as input data sources. Testing results from 297 cases show that the proposed system can be applied for RDF graph validation in various practical cases.