• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.600-603
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• 2004

웹의 확산과 더불어 웹 상에 존재하는 정보의 양은 예측할 수 없을 정도로 증가하였고, 웹 사용자의 이용수준과 요구사항도 매우 다양하고 복잡해졌다. 이러한 환경에서 사용자 요구에 맞는 적절한 정보를 제공하기 위해서는 정확하고 필요한 정보만을 효율적으로 추출하고, 웹 정보들 간의 관계와 정보 자원들 사이의 의미적 연관성을 기술하는 지식 표현 수단으로 온톨로지(Ontology)가 필요하게 되었다. 이를 위해 W3C는 다양한 온톨로지를 통합하여 시맨틱 웹에서 웹 정보들간의 의미적 표현을 기술할 수 있는 표준으로 OWL(Web Ontology Language)을 제안하였으나, 이를 활용하기 위한 저작도구가 전무한 실정이다. 따라서 본 논문은 W3C에서 표준으로 제안하고 있는 OWL의 속성들을 분석하여, OWL 구문을 직관적이고 효율적으로 생성, 저작할 수 있는 OWL builder를 설계 및 구현하였다.

• Journal of Digital Contents Society
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• v.13 no.1
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• pp.43-52
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• 2012

For accurate search on information resources, it is needed to manage gradual changes in ontology efficiently. Recently, because ontology is often written using OWL, techniques that can manage changes in OWL documents are required. To meet these needs, in this paper, we classify changeable elements to detect changes in OWL ontology and propose a storage schema that can manage the changes according to the characteristics of each element. And we suggest the possibility of improving performance of query processing using views that provide information about classes or properties in each ontology version. The proposed storage schema stores changes in metadata associated with each ontology version. In addition, it can manage metadata that must be added or deleted through reasoning when ontology changes. So, the proposed storage schema can support queries about history of changes in ontology and provide accurate and valid metadata that is suitable for user-selected ontology version.

• Journal of the Korea Society of Computer and Information
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• v.20 no.3
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• pp.29-45
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• 2015

This paper proposes an implementation of SPARQL-DL, which is a query language for OWL ontologies, for query-answering over the OWL ontologies virtually generated from existing RDBs. The proposed SPARQL-DL processor internally translates input SPARQL-DL queries into SQL queries and then executes the translated queries. There are two advantages in the query processing method. First, another repository to store OWL ontologies generated from RDBs is not required. Second, a large ABox generated from an RDB instance is able to be served without using Tableau algorithm based reasoners which have a problem in large ABox reasoning. Our algorithm for query rewriting is designed to create one corresponding SQL query from one input SPARQL-DL query to minimize the overhead by establishing connections with RDBs.

• Journal of KIISE:Software and Applications
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• v.32 no.6
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• pp.461-472
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• 2005

In this paper, we design and implement a graphical bio-ontology management system based on OWL(Web Ontology Language). It allows domain experts to easily manage sophisticated bio-ontologies in which biological knowledge is encoded. The knowledge can be seamlessly modeled into the ontology by well defined graphical notations, which capture most of subtle semantics inherently existing between biological terms. Our system provides a new construction mechanism, which can determine a considerable part of relationships between terms by their inheritance and inverse-inheritance. For keeping their semantics to be consistent, the mechanism supplies domain experts with information available from relationships being constructed or already constructed. The constructed ontology is basically formatted by OWL, which may benefit from its powerful semantic expressiveness. Additionally, it can be automatically translated into other standard languages without semantic loss, such as RDF/RDFS, DAML+OIL and so on. The main characteristics of our system is that it enables domain experts to delicately model the bio-ontology by the visualized construction mechanisms adopting well-defined graphical notations based on OWL.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.11a
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• pp.213-216
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• 2005

W3C에서는 온톨로지의 표준 언어로 OWL(Web Ontology Language)을 발표하였고 이를 활용한 온톨로지가 다양한 곳에 적용되어 구축이 되고 있다. 하지만, DL(Description Logic)기반인 OWL언어가 표현할 수 있는 규칙의 한계로 인하여 이를 확장하기 위한 연구가 활발히 진행되고 있다. 이러한 연구를 통하여 W3C에서는 OWL과 RuleML(Rule Markup Language)을 통합하여 규칙(Rule)에 대한 표현력이 더욱 향상된 SWRL(Semantic Web Rule Language) 언어를 제안하였다. 현재 이러한 연구는 OWL, SWRL 온톨로지 언어를 활용하고 Racer, Jess와 같은 엔진을 통하여 추론을 하는 형태로 활성화 되어 가고 있다. 하지만 이러한 형태로 온톨로지를 구축하는데 있어서 Racer를 이용한 DL추론, Jess를 이용한 Rule-base추론이 병행되고 있다. 이에 따라 본 논문에서는 온톨로지를 추론하기 위한 엔진으로 Racer와 Jess의 병행이 아닌, Jess를 이용하여 DL기반언어인 OR온톨로지를 추론하는 것 뿐 만 아니라 SWRL언어의 규칙 또한 추론할 수 있도록 한다. 이러한 시스템을 구축하기 위해 OWL을 Jess언어를 이용하여 추론할 수 있도록 개발된 OWLJessKB라는 툴과 SWRL언어를 추론하기 위해 Jess언어로 변환하여 이를 추론하는 SWRL Factory, 그리고 이출 이용하여 통합 추론하기 위한 세가지 통합 추론 플랫폼을 제안한다.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.5
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• pp.385-389
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• 2009

As a new community forming environment, the blog platform enables sharing of the resources in blogosphere through active information exchange. Many researches have been performed to recommend appropriate resources to users from vast amounts of blog resources. As one of the solutions OSEM defines the knowledge base in the blogosphere with ontology for effectively modeling it. In this paper, we propose a technique of converting the knowledge base into the OWL ontology for sharing it on the semantic web environment. An inference method is then applied to the OWL ontology for recommending interest blog communities. For this aim, a mapping method is offered and then SWRL inference and SPARQL query based on the ontology are employed to extract interest blog communities.

• Journal of KIISE:Software and Applications
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• v.36 no.7
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• pp.509-522
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• 2009

The W3C Ontology Working Group has recently developed OWL as an ontology language for the Semantic Web. OWL, however, fails to perform the process of reasoning about temporal knowledge because it lacks full-pleadged semantics for temporal language. Entities in the real world are changing as time passes, while new facts are being introduced as new events occur. KBs without temporal information are incomplete and incorrect. In this paper, we propose an extended temporal ontology language called TL-OWL which provides an abstract syntax and semantics for representing and reasoning about temporal information in the Semantic Web.

• Journal of Biomedical Engineering Research
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• v.36 no.4
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• pp.128-134
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• 2015

Recently, the structured data format in RDF/OWL has played an increasingly vital role in the semantic web. We converted pediatric and oncologic nuclear medicine imaging reports in free text into RDF/OWL format and evaluated the usefulness of nuclear medicine imaging reports in RDF/OWL by comparing SPARQL query results with the manually retrieved results by physicians from the reports in free text. SPARQL query showed 95% recall for simple queries and 91% recall for dedicated queries. In total, SPARQL query retrieved 93% (51 lesions of 55) recall and 100% precision for 20 clinical query items. All query results missed by SPARQL query were of some inference. Nuclear medicine imaging reports in the format of RDF/OWL were very useful for retrieving simple and dedicated query results using SPARQL query. Further study using more number of cases and knowledge for inference is warranted.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2007.11a
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• pp.451-456
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• 2007

유비쿼터스 컴퓨팅 환경을 구축하기 위해서는 사용자 및 주변 상황에 관한 인지기술이 필수적이다. 이에 따라 이기종 분산형 시스템에서 언어와 기종에 영향을 받지 않고 사용자 Context를 인지하고 표현하는 문제는 해결해야할 중요한 과제로 대두되었다. 이에 따라, 본 논문에서는 이 과제를 해결하기 위하여 시맨틱 웹 기술 및 퍼지 개념을 이용하여 사용자 Context를 기술하는 것을 제안한다. 온톨로지는 컴퓨터가 정보자원의 의미를 파악하고 자동적으로 처리할 수 있도록 고안된 지식표현 언어이므로 이기종 시스템 하에서의 사용자 Context를 표현하는데 적합하다. 한편, 사용자가 접할 실세계의 환경은 일반집합(Crisp Set)으로 표현하기 힘들기 때문에 본 논문에서는 퍼지개념과 표준 웹 온톨로지 언어 OWL이 융합된 Fuzzy OWL언어를 사용했다. 본 논문에서 제안하는 방법은 Context를 Fuzzy OWL로 표현하기 위하여 먼저 사용자가 접한 환경정보들을 수치로 표현한다. 그리고 이를 OWL로 기술하며 OWL로 표현된 사용자 Context를 Fuzzy OWL로 변환한다. 마지막으로 퍼지 개념이 포함된 사용자 Context를 이용하여 자동적인 상황인지가 가능한지 여부를 퍼지 추론 엔진인 FiRE를 사용하여 실험한다. 본 논문에서 제시한 방법을 사용하면 이기종 분산시스템에서도 사용할 수 있는 형태로 Context를 기술할 수 있다. 그리고 기술된 Context를 기반으로 현재 사용자가 접한 환경의 상태를 추론할 수 있다. 또한 퍼지 기술 로직 언어(Fuzzy Description Logic)기반 추론기인 FiRE를 이용하여 이를 검증한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.11a
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• pp.801-802
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• 2009

Currently, XML and its schema language have become the standard for data representation and information exchange format on the current web. Unfortunately, problems happen when integrating different data sources since XML mainly supports the document structure but lack consideration on sharing knowledge of data. Meanwhile, Semantic Web technologies, such as Web Ontology Language (OWL), can include the structure as well as the semantics of the data. Therefore, finding a way to integrate XML data as OWL ontology receives a high interest nowadays. In this paper we present a mapping notation to convert XML Schema to OWL domain knowledge and an effective method to transform XML instances into OWL individuals. While keeping the XML original structure, our work also adds more semantics for the XML document. Moreover, whole of the transformation processes are done automatically without any user interference. Further, our transforming approach provides the solution for duplicate element names in XML document which has not mentioned in the previous work. Our results in existing OWL syntaxes can be loaded immediately by OWL editors and Semantic Web applications.