• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.560-562
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• 2003

시멘틱 웹상에서는 정보 리소스들이 서로 의미적으로 연결되어. 이를 컴퓨터가 처리할 수 있다. Resource Description Framework (RDF)는 이런 의미적 연결성을 제공한다. 시멘틱 웹이 발전하기 위해서는 RDF 데이터를 효율적으로 관리하기 위한 방법이 매우 중요하다. 본 논문에서는 RDF 데이터를 XML 데이터베이스 시스템에 저장하고 이를 검색하는 기법을 제안한다 XML 데이터베이스 시스템을 사용함으로써 XML 데이터와 RDF 데이터를 통합적이고 효율적으로 관리할 수 있다. 또한. 효율적인 검색 방법과 성능을 향상시킬 수 있는 방법들을 제안하고 있다. 논문에서 제안한 질의 처리 기법은 기존 연구 보다 나은 성능을 보여준다.

• Journal of the Korea Society of Computer and Information
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• v.22 no.6
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• pp.57-68
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• 2017

The Linked Open Data(LOD) cloud is quickly becoming one of the largest collections of interlinked datasets and the de facto standard for publishing, sharing and connecting pieces of data on the Web. Data publishers from diverse domains publish their data using Resource Description Framework(RDF) data model and provide SPARQL endpoints to enable querying their data, which enables creating a global, distributed and interconnected dataspace on the LOD cloud. Although it is possible to extract structured data as query results by using SPARQL, users have very poor in analysis and visualization of RDF data from SPARQL query results. Therefore, to tackle this issue, based on Formal Concept Analysis, we propose a novel approach for analyzing and visualizing useful information from the LOD cloud. The RDF data analysis and visualization technique proposed in this paper can be utilized in the field of semantic web data mining by extracting and analyzing the information and knowledge inherent in LOD and supporting classification and visualization.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.2
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• pp.125-133
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• 2009

RDF is widely used as the ontology language for representing metadata on the semantic web. Since ontology models the real-world, ontology changes overtime. Thus, it is very important to detect and analyze changes in knowledge base system. Earlier studies on detecting changes between RDF models focused on the structural differences. Some techniques which reduce the size of the delta by considering the RDFS entailment rules have been introduced. However, inferencing with RDF models increases data size and upload time. In this paper, we propose a new change detection using RDF reasoning that only computes a small part of the implied triples using backward chaining strategy. We show that our approach efficiently detects changes through experiments with real-life RDF datasets.

• New & Renewable Energy
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• v.7 no.1
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• pp.29-35
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• 2011

The waste treatment fee and energy production effect of Wonju city RDF plant, the first RDF manufacturing plant in Korea, were investigated in the study. All plant operation data, like total weight of received wastes, produced RDF and separated rejects in processes were fully recorded for mass balance calculation of the plant in 2009. Also all consumed oil and electricity were recorded for energy balance calculation. The results showed that the waste treatment fee not including the RDF sales price of 25,000 won/ton-RDF was 116,573 won/ton-MSW and it went down to 105,298 won when included the RDF price. Produced RDF was 40.2% of total received waste in weight. Three components analysis by mass balance calculation of total received waste showed that Wonju city's MSW was 32.4% of combustible, 37.5% of water and 30.1% of incombustible respectively. Energy effect was found that total amount of produced energy was about 4 times more than that of consumed energy.

• The Journal of Society for e-Business Studies
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• v.9 no.3
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• pp.79-94
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• 2004

W3C has developed the RDF standard for utilizing ontology in Web applications. This paper presents extracting, storing, and applying ontology on product data. The management and document information included in DWG files is focused as an example. By analyzing the relationship among the drawing data, the RDF schema is designed frist. Based on the schema ontology is extracted and stored in XML files. As an application of the stored ontology, we the schema ontology is extracted and stored in XML files. As an application of the stored ontology, we can reconfigure the sitemap of drawing data repositories. In this example, the users can select the view that he or she is interested in (e.g., designer, document, project). With such various views of an drawing data repository, the users can access the specific data more effectively.

• Journal of KIISE:Databases
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• v.35 no.2
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• pp.112-124
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• 2008

RDF and OWL are the primary base technologies for implementing Semantic Web. Recently, many researches related with them, or applying them into the other application domains, have been introduced. However, relatively little work has been done for securing the RDF and OWL data. In this article, we briefly introduce an RDF triple based model for specifying RDF access authorization related with RDF security. Next, to efficiently find the authorization conflict by RDF inference, we introduce a method using prime number graph labeling in detail. The problem of authorization conflict by RDF inference is that although the lower concept is permitted to be accessed, it can be inaccessible due to the disapproval for the upper concept. Because by the RDF inference, the lower concept can be interpreted into the upper concept. Some experimental results show that the proposed method using the prime number graph labeling has better performance than the existing simple method for the detection of the authorization conflict.

• Journal of KIISE:Databases
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• v.36 no.6
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• pp.422-433
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• 2009

As an effort to secure Semantic Web, in this paper, we introduce an RDF access authorization model based on an ontology hierarchy and an RDF triple pattern. In addition, we apply the authorization model to RDF query validation for approved access authorizations. A subscribed SPARQL or RQL query, which has RDF triple patterns, can be denied or granted according to the corresponding access authorizations which have an RDF triple pattern. In order to efficiently perform the query validation process, we first analyze some primary authorization conflict conditions under RDF subsumption inference, and then we introduce an efficient query validation algorithm using the conflict conditions and Dewey graph labeling technique. Through experiments, we also show that the proposed validation algorithm provides a reasonable validation time and when data and authorizations increase it has scalability.

• Journal of the Korea Society of Computer and Information
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• v.16 no.7
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• pp.95-103
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• 2011

The actual utilization of Semantic Web technology which aims to provide more intelligent and automated service for information retrieval over the Web becomes gradually reality. RDF is widely used as the one of standard formats to present and manage the voluminous data on the Web. Efficient query processing on RDF data, therefore, is one of the ongoing research topics. Retrieving resources having a specific association from a given resource is the typical query processing type and several researches for this have done. However the most of previous researches have not fully considered discovering the complex relationship among resources such as returning the association between resources as the query processing result. This paper introduces the indexing and query processing for ${\rho}$-intersect operation which is one of the semantic association retrieval types. It includes an indexing scheme using suffix array and optimal processing approaches for handling ${\rho}$-intersect operation. The experimental evaluations shows that the average execution times for the proposed approach is 3~7 times faster than the previous approach.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.195-197
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• 2016

시멘틱웹을 구축하는 표준언어인 RDF (Resource Description Framework)는 언어의 그래프 기반 특성으로 인해 일반적인 방식들로는 효과적인 저장과 추출이 어렵다. 더욱이 대용량 RDF 데이터의 저장과 추출에는 성능문제가 더욱 커지므로 많은 연구들이 이루어지고 있다. 본 논문에서는 SPARQL을 지원하면서 RDF 파일들을 효과적으로 저장하고 검색할 수 있는 저장방식에 대해 연구한 결과를 제시한다. RDF 데이터를 전처리를 통해 RDF의 트리플(주어:subject, 술어:property, 목적어:Object)에서 중복되는 주어(S)나 목적어(O)를 묶고, 사용자가 SPARQL 형식으로 검색했을 때 이용자가 주어부분을 변수로 두었는지 아니면 서술어 부분을 변수로 두어 찾는지에 따라 검색어와 유사한 단어 클러스터를 찾아준다. 동일 단어에 대해 여러 번 검색되던 부분을 한 번 검색으로 처리할 수 있기 때문에 효율이 높아진다.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.187.1-187.1
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• 2011

RDF(Refuse-Derived Fuel) is a fuel of pelletized form made of combustible solid wastes and can not only be used as alternative energy to fossil fuel but also solve troubles in thermal uses of incinerator. As the first stage for obtaining elementary data required to develop criteria of raw materials appropriate to RDF combustion facilities actively spread recently in Korea, preliminary experiments were conducted on CO, SOx, NOx and HCl production and reduction characteristics in combustion of RDF. RDF samples weighing 2~3 g per a sample were manufactured in a lab-scale way and combustion tests of RDF were carried out in electric furnace with quartz tube of 50 mm inside diameter.