• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.248-251
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• 2010

레거시시스템 관계형 데이터의 효율적인 재사용을 위해 많은 연구가 있었다. 온톨로지 기반 분류기법의 적용으로 문제점이었던 의미적 해석 및 처리를 해결하고, 사람의 이해가 아닌 컴퓨터가 이해할 수 있도록 하는 연구가 필요하다. 본 논문에서는 온톨로지 기반 효율적 재사용을 위해 관계형 데이터의 유형 분류기법을 적용한 SDTC 기법의 제안하였고 결과물로 생성된 정보를 저장하는 SDR 데이터 저장소가 생성된다. 도한 SDR 데이터의 통합으로 향상된 재사용을 할 수 있도록 하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.337-338
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• 2006

The requirement to reuse a design knowledge have been enlarged with the automation of a design system. A design knowledge gives logical and technical meanings to design data of a problem area. The representation of the knowledge is distributed and developed independently. For this reason, we need a general methodology with a semantic interoperability of design knowledge. In this paper, we accept previous requirements by using semantic query system with ontology repository.

• Journal of KIISE:Databases
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• v.35 no.3
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• pp.243-256
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• 2008

With rapid growth of Internet, the amount of information in the Web is increasing exponentially. However, information on the current Web is understandable only for human, and thus it makes the exact information retrieval difficult. For solving this problem, the Semantic Web is suggested and we must use ontology languages that can endow data to semantics for implementing it. One of the representative ontology languages is OWL(Web Ontology Language) adopted as a recommendation by the World-Wide Web Consortium. OWL has richer expression power and formal semantics than other ontology languages such as RDF and RDF-S. In addition, OWL includes hierarchical structure information between classes or properties. Therefore, an efficient OWL storage model considering hierarchical structure for effective information retrieval on the Semantic Web is required. In this paper, we suggest the XPOS(XPath-based OWL Storage) model including hierarchy information between classes or properties as XPath form and enabling intuitive and effective information retrieval. Also, we show the comparative evaluation results on the performance of XPOS model, Sesame, and the XML storage-based storage model regarding query processing.

• Journal of KIISE:Databases
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• v.35 no.3
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• pp.231-242
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• 2008

W3C has selected OWL as a standard for Web ontology description and a necessity of research on storage models that can store OWL ontologies effectively has been issued. Until now, relational model-based storage systems such as Jena, Sesame, and DLDB, have been developed, but there still remain several issues. Especially, they lead inefficient query processing performance. The structural problems of their low query processing performance are as follow: Jena has a simple structure which is not normalized and also stores most information in a single table. It exponentially decreases the performance because of comparison with unnecessary information for processing queries requiring join operations as well as simple search. The structures of storages(e.g., Sesame) have been completely normalized. Therefore it executes many join operations for query processing. The storages require many join operations to find simply a specific class. This paper proposes a storage model to resolve the problems that the query processing performance is decreased because of non-normalization or complete normalization of the existing storages. To achieve this goal, we analyze the problems of existing storage models as well as relations of OWL elements and query patterns. The proposed model, defined with the analysis results, provides an optimal normalized structure to minimize join operations or unnecessary information comparison. For the experiment of query processing performance, a LUBM data sets are used and query patterns are defined considering search targets and their hierarchical relations. In addition, this paper conducts experiments on correctness and completeness of query results to verify data loss of the proposed model, and the results are described. With the comparative evaluation results, our proposal showed a better performance than the existing storage models.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.485-488
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• 2005

월드와이드웹(WWW) 기술은 폭발적으로 증가하고 있는 웹 데이터들의 의미적인 정보를 효과적으로 처리하기에는 많은 문제점이 있다. 이러한 문제점을 해결하기 위하여 1999년 말에 제안된 시맨틱 웹은 온톨로지를 기반으로 하고 있다. 그러나 온톨로지 생성에 관한 많은 연구들은 많은 시간과 비용이 소비된다. 이와 같은 문제를 해결하기 위하여 우리는 데이터베이스에서 온톨로지를 생성할 수 있는 방법을 제안한다. 데이터베이스는 도메인을 잘 나타내고 있는 정보의 저장소이므로 데이터베이스로부터의 온톨로지 생성은 분석, 설계 등의 사전 작업이 필요하지 않다. 우리는 데이터베이스에서 스키마를 추출, 뼈대그래프를 생성하고 개념그래프로 확장하여 도메인을 잘 나타낼 수 있는 온톨로지를 생성한다. 끝으로 알고리즘을 통한 생성을 함으로서 제안된 생성방법을 검증한다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.124-127
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• 2005

The increased use of ontologies fur knowledge sharing emerges in many applications where knowledge applicability plays a critical role. The trend demands the need for an infrastructure that allows management tools to use ontology more easily such as ontology editors, storing, integration and inference engines towards comprehensive ontology-based solutions. We call such an infrastructure as ontology repository. This paper designed ontology repository for scalable ontology data

• 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.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.111-114
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• 2012

실시간으로 발생되는 대량의 데이터를 효율적으로 저장하기 위한 연구는 분산/병렬 처리를 위한 하둡 및 NoSQL과 관련한 빅 데이터 처리 기술을 통해 진행 중에 있다. 하지만 시맨틱 웹 분야에서 발생되는 대량의 데이터를 처리하기 위한 모델은 현재 연구가 진행되고 있지 않다. 본 논문에서는 시맨틱 웹 환경에서 발생되는 대량의 온톨로지 데이터를 빅 데이터 처리가 가능한 NoSQL 분야인 HBase 데이터베이스에 분산 저장할 수 있는 매핑 규칙을 제안한다. 이와 같은 매핑 규칙을 통해 시맨틱 웹 환경에서도 대량으로 발생될 수 있는 데이터들을 효율적으로 분산 저장 할 수 있다.

• Journal of KIISE:Databases
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• v.35 no.6
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• pp.505-517
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• 2008

This paper proposes a rewriting algorithm of OWL-DL ontology query in SPARQL. Currently, to obtain inference results of given SPARQL queries, Web ontology repositories construct inference ontology models and match the SPARQL queries with the models. However, an inference model requires much larger space than its original base model, and reusability of the model is not available for other inferrable SPARQL queries. Therefore, the aforementioned approach is not suitable for large scale SPARQL query processing. To resolve tills issue, this paper proposes a novel SPARQL query rewriting algorithm that can obtain results by rewriting SPARQL queries and accomplishing query operations against the base ontology model. To achieve this goal, we first define OWL-DL inference rules and apply them on rewriting graph pattern in queries. The paper categorizes the inference rules and discusses on how these rules affect the query rewriting. To show the advantages of our proposal, a prototype system based on lena is implemented. For comparative evaluation, we conduct an experiment with a set of test queries and compare of our proposal with the previous approach. The evaluation result showed the proposed algorithm supports an improved performance in efficiency of the inferrable SPARQL query processing without loss of completeness and soundness.

• The Journal of Society for e-Business Studies
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• v.18 no.2
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• pp.153-173
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• 2013

The ontology has been gaining increasing interests by recent arise of the semantic web and related technologies. The focus is mostly on inference query processing that requires high-level techniques for storage and searching ontologies efficiently, and it has been actively studied in the area of semantic-based searching. W3C's recommendation is to use RDFS and OWL for representing ontologies. However memory-based editors, inference engines, and triple storages all store ontology as a simple set of triplets. Naturally the performance is limited, especially when a large-scale ontology needs to be processed. A variety of researches on proposing algorithms for efficient inference query processing has been conducted, and many of them are based on using proven relational database technology. However, none of them had been successful in obtaining the complete set of inference results which reflects the five characteristics of the ontology properties. In this paper, we propose a new index structure called hyper cube index to efficiently process inference queries. Our approach is based on an intuition that an index can speed up the query processing when extensive inferencing is required.