• Journal of KIISE:Computing Practices and Letters
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• v.15 no.5
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• pp.390-394
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• 2009

The semantic web-based social network is highly useful in a variety of areas. In this paper we make diverse analyses of the FOAF-based social network, and propose an expert recommendation system. This system presents useful method of ontology-based social network using SparQL, RDFS inference, and visualization tools. Then we apply it to real social network in order to make various analyses of centrality, small world, scale free, etc. Moreover, our system suggests method for analysis of an expert on specific field. We expect such method to be utilized in multifarious areas - marketing, group administration, knowledge management system, and so on.

• Journal of the Korea Society of Computer and Information
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• v.14 no.1
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• pp.35-45
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• 2009

According to the widespread use of ontology documents, a management system which store ontology data and process queries is needed for retrieving semantic information efficiently. In this paper I propose a storage schema that stores and retrieves semantic web documents based on RDF/RDFS ontology language developed by W3C in a relational databases. Specially, the proposed storage schema is designed to retrieve efficiently hierarchy information and to increase efficiency of query processing. Also, I describe a mechanism to transform RQL semantic queries to SQL relational queries and build up database using MS-ACCESS and implement in this paper. According to the result of implementation, we can blow that not only data query based on triple model but also query for schema and hierarchy information are transformed simply to SQL.

• Journal of KIISE
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• v.43 no.4
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• pp.450-459
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• 2016

Every year, RDFS data tends further toward scalability; hence, the manner of SPARQL processing needs to be changed for fast query. The query processing method of SPARQL has been studied using a scalable distributed processing framework. Current studies indicate that the query engine based on the scalable distributed processing framework i.e., Hadoop(MapReduce) is not suitable for real-time processing because of the repetitive tasks; in addition, it is difficult to construct a query engine based on an In-memory Distributed Query engine, because distributed structure on the low-level is required to be considered. In this paper, we proposed a method to construct a query engine for improving the speed of the query process with the mass triple data. The query engine processes the query of SPARQL using the SparkSQL, which is an In-memory based, distributed query processing framework. SparkSQL is a high-level distributed query engine that facilitates existing SQL statement. In order to process the SPARQL query, after generating the Algebra Tree using Jena, the Algebra Tree is required to be translated to Spark Algebra Tree for application in the Spark system, and construction of the system that generated the SparkSQL query. Furthermore, we proposed the design of triple property table based on DataFrame for more efficient query processing in the Spark system. Finally, we verified the validity through comparative evaluation with the query engine, which is the existing distributed processing framework.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.07a
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• pp.309-310
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• 2012

최근에 웹 온톨로지 언어를 사용한 웹 서비스와 애플리케이션들이 많이 개발됨에 따라 RDF/S를 기반으로 한 온톨로지 문서의 크기가 증가되었고 이로 인해 효율적으로 문서를 저장하고 검색하기위한 시맨틱 웹 정보관리 시스템의 필요가 대두되었다. 본 논문에서는 시맨틱 웹 정보관리 시스템에서 클래스와 프로퍼티의 삭제 알고리즘을 제안한다. 제안한 삭제 알고리즘에서는 클래스나 프로퍼티가 삭제될 때에 이를 반영하여 계층 정보의 스키마 정보가 변경된다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.139-141
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• 2004

본 논문에서는 웹 상의 미술 작품 검색하기 위해 기존의 키워드 매칭 검색 대신에 시맨틱 기반의 확장된 검색 방법을 소개한다. 온톨로지를 만들기 위해서는 많은 온톨로지 관련 언어가 있다. 그 중 최근의 연구 방향은 RDFS/RDF와 OWL로 작성된 온톨로지와 온톨로지의 추론 분야이다. 지금까지의 정보 검색이 단순한 구문중심의 검색이었다면 앞으로의 정보 검색은 의미 중심의 지식 기반의 정보 검색을 발전할 것이다. 이에 본 논문이 온톨로지를 활용한 지식 기반 검색 시스템을 제안한다.

• 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.

• Journal of the Korea Society of Computer and Information
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• v.14 no.11
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• pp.21-30
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• 2009

Semantic web uses ontology languages such as RDF, RDFS, and OWL to define the metadata on the web. There have been many researching efforts in the semantic web technologies based on an agent for extracting triple and relation about concept of ontology. But the extraction of relation and triple about the concept of ontology based on an agent ends up writing a limited query statement as characteristics of an agent. As for this, there is the less of flexibility when extracting triple and relation about the other concept of ontology. We are need a query tool for flexible information retrieval of ontology that is can access the standard ontology and can be used standard query language. In this paper, we propose a SPARQL query tool that is can access the OWL ontology via HTTP protocol and it can be used to make a query. Query result can be output to the soap message. These operations can be support the web service.

• Journal of the Korea Organic Resources Recycling Association
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• v.17 no.3
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• pp.27-39
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• 2009

The main objective of this study is to investigate the characteristics of combustion by analyzing fuel gases from a combustion equipment with various combustion conditions for refuse-derived fuels (RDFs). CO gas is a parameter for indicating of incomplete combustion during a combustion process. The lowest CO gas was produced when the experiment conditions were m=2 under air-fuel condition and $800^{\circ}C$. $CO_2$ gas is a final product after complete combustions. The highest amount of $CO_2$ gas was produced when the experiment conditions were m=2 under air-fuel condition and $800^{\circ}C$. The highest level of $SO_2$ gas was produced in S.1 sample containing the highest sulfur. The highest level of NOx gas was produced in S.1 sample with the highest nitrogen content and air-fuel condition of m=2 under temperature of $800^{\circ}C$. HCl gas that is generated by reacting with metals catalyst through oxygen catalyst reaction during combustion process is a precursor of dioxin formation. The higher level of HCl gas was produced in the sample with higher chlorine content. The lowest level of HCl gas was produced when the experiment conditions were air-fuel condition of m=2 and $800^{\circ}C$. The lowest level of $NH_3$ gas was generated when the experiment condition was m=2 under air-fuel condition and after 3 minutes. Air-fuel condition is more important to create $NH_3$ gas than operating temperatures. Higher level of $H_2S$ gas was generated in S.1 sample with the higher sulfur content and was created in RDFs that contain higher mixture ratios of sewage sludge and food wastes. A result of combustion, gases and gases levels from the combustion of S.1 and S.2 were very similar to the combustion of a stone coal. As results of this research, when evaluating the feasibility of the RDFs, the RDFs could be used as auxiliary and main fuels.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.207.1-207.1
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• 2010

The emission difference of SOx, NOx, TSP and dioxine was investigated in commercial CFB boiler, when coal and three kinds of RDFs were co-combusted respectively. The each mixing ratio was 7.5% RPF, 7.5% RDF and 10% SDF with coal. Emitting dioxine concentration was proportioned to the chlorine content of RDF. No trouble was found on normal boiler operation during co-combustion. These RPF, SDF and RDF could be determined to be a good alternative fuel of general coal.

• Journal of Korea Multimedia Society
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• v.21 no.2
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• pp.158-165
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• 2018

Since a large amount of multimedia image has dramatically increased, it is important to search semantically relevant image. Thus, several semantic image annotation methods using RDF(Resource Description Framework) model in mobile environment are introduced. Earlier studies on annotating image semantically focused on both the image tag and the context-aware information such as temporal and spatial data. However, in order to fully express their semantics of image, we need more annotations which are described in RDF model. In this paper, we propose an annotation method inferencing with RDFS entailment rules and user defined rules. Our approach implemented in Moment system shows that it can more fully represent the semantics of image with more annotation triples.