• Journal of Digital Contents Society
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• v.9 no.2
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• pp.285-293
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• 2008

In Semantic Web, metadata and ontology for representing semantics and conceptual relationships of information resources are essential factors. RDF and RDF Schema are W3C standard models for describing metadata and ontology. Therefore, many studies to store and retrieve RDF and RDF Schema documents are required. In this paper, we focus on some results of analyzing available query patterns considering both RDF and RDF Schema and classify queries on RDF and RDF Schema into the three patterns. RDF and RDF Schema can be represented as graph models. So, we proposed some strategies to store and retrieve using the graph models of RDF and RDF Schema. We can retrieve entities that can be arrived from a certain class or property in RDF and RDF Schema without a loss of performance on account of multiple joins with tables.

• Journal of KIISE:Databases
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• v.33 no.5
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• pp.476-485
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• 2006

The Resource Description Framework(RDF), which emerged with the semantic web, is settling down as a standard for representing information about the resources in the World Wide Web Hence, a lot of research on storing and query processing RDF documents has been done and several RDF storage systems, such as Sesame and Jena, have been developed. But the research on updating RDF documents is still insufficient. When a RDF document is changed, data in the RDF triple store also needs to be updated. However, current RDF triple stores don't support incremental update. So updating can be peformed only by deleting the old version and then storing the new document. This updating method is very inefficient because RDF documents are steadily updated. Furthermore, it makes worse when several RDF documents are stored in the same database. In this paper, we propose an incremental update algorithm on RDF, documents in triple stores. We use a text matching technique for two versions of a RDF document and compensate for the text matching result to find the right target triples to be updated. We show that our approach efficiently update RDF documents through experiments with real-life RDF datasets.

• Journal of KIISE:Databases
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• v.35 no.6
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• pp.495-504
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• 2008

Recently, there has been much work on supporting keyword search not only for text documents, but a]so for structured data such as relational data, XML data, and RDF data. In this paper, we propose an efficient keyword search method for RDF data. The proposed method first groups related nodes and edges in RDF data graphs to reduce data sizes for efficient keyword search and to allow relevant information to be returned together in the query answers. The proposed method also utilizes the semantics in RDF data to measure the relevancy of nodes and edges with respect to keywords for search result ranking. The experimental results based on real RDF data show that the proposed method reduces RDF data about in half and is at most 5 times faster than the previous methods.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.2
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• pp.49-63
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• 2008

RDF is the base ontology model which is used in Semantic Web defined by W3C. OWL expands the RDF base model by providing various vocabularies for defining much more ontology relationships. Recently Jain and Farkas have suggested an RDF access control model based on RDF triple. Their research point is to introduce an authorization conflict problem by RDF inference which must be considered in RDF ontology data. Due to the problem, we cannot adopt XML access control model for RDF, although RDF is represented by XML. However, Jain and Farkas did not define the authorization propagation over the RDF upper/lower ontology concepts when an RDF authorization is specified. The reason why the authorization specification should be defined clearly is that finally, the authorizatin conflict is the problem between the authorization propagation in specifying an authorization and the authorization propagation in inferencing authorizations. In this article, first we define an RDF access authorization specification based on RDF triple in detail. Next, based on the definition, we analyze the authoriztion conflict problem by RDF inference in detail. Next, we briefly introduce a method which can quickly find an authorization conflict by using graph labeling techniques. This method is especially related with the subsumption relationship based inference. Finally, we present a comparison analysis with Jain and Farkas' study, and some experimental results showing the efficiency of the suggested conflict detection method.

• Applied Chemistry for Engineering
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• v.23 no.3
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• pp.333-338
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• 2012

To verify the utilization of fluff refuse derived fuel (RDF) as energy source, the combustion charateristic has been studied by an experimental combustion furnace under various temperatures. The characteristics of flue gas, dust and residue from fluff RDF combustion has been analyzed and compared with those of pelletized RDF. From this work, it was found that the incomplete combustion of fluff RDF was greater than that of pelletized RDF because the combustion reaction rate of fluff RDF was faster than that of pelletized RDF, and oxgen concentration in fluff RDF combustion decreased rapidly. It was also found that carbon monoxide concentration of flue gas from fluff RDF combustion increased with combustion temperature because the oxygen consumption and the incomplete combustion increased. Therefore, it is felt that the combustion operation conditions of fluff RDF should be carefully determined.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.705-708
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• 2007

RDF means Refuse Derived Fuel, it is made pellets with combustible materials in municipal waste and RDF use a renewable energy instead with natural coal. RDF Technology is a essential one to treat municipal waste steadily and secure a energy source in Korea. Already RDF Technology commercialize in Japan, USA, Europe and there are many of RDF production plants and utilization facilities. The first RDF plant was constructed in Wonju Korea in October 2006 and is good operation. Government accelerate establishment of concerning laws and support to develop technology and spread RDF plants and utilization facilities.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.531-534
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• 2006

The first RDF production plant in Korea is going to start commercial operation at Won-Ju city in October this year, where municipal solid waste is treated and converted to RBF. Korean government is preparing the quality standard of RDF and starting a new waste policy of RDF promotion instead of general waste treatment technologies such as incineration or landfill. In Europe the EU member states have decided the united quality standard of RDF to increase the amount of new & renewable energy through the promotion of RDF utilization. New quality standard of RDF and trade market of RDF in Europe is introduced in this paper.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.1-9
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• 2005

As the amount of data on the web increase, it is difficult to search what we want exactly. Therefore, much researches are attempted to search web resources efficiently. So, W3C established the standard that give meanings to resources on the web using RDF metadata. The RDF metadata had been mainly described a document data on the web. But it is difficult to create automatically the metadata for application programs than the document data. This paper proposes a method to use RDF metadata to search application programs. Firstly, we define RDF data model that stores the information of the application programs and RDF schema that references the RDF data model. And we design a prototype system to search application programs. This system meets expectation, getting the application to fullfill the needs of user, and has the efficiency of the searching function.

• Journal of Korean Library and Information Science Society
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• v.48 no.3
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• pp.233-257
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• 2017

In this paper, we propose an effective method to convert and construct the MEDLINE, the world's largest biomedical bibliographic database, into linked data. To do this, we first derive the appropriate RDF schema by analyzing the MEDLINE record structure in detail, and convert each record into a valid RDF file in the derived schema. We apply the dual batch registration method to streamline the subject URI duplication checking procedure when merging all RDF files in the converted record unit and storing it in a single RDF triple storage. By applying this method, the number of RDF triple storage accesses for the subject URI duplication is reduced from 26,597,850 to 2,400, compared with the sequential configuration of linked data in units of RDF files. Therefore, it is expected that the result of this study will provide an important opportunity to eliminate the inefficiency in converting large volume bibliographic record sets into linked data, and to secure promptness and timeliness.

• Journal of the Korean Society for information Management
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• v.20 no.3
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• pp.241-259
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• 2003

The Basic Semantic Register(BSR) is and official ISO register designed for interoperability among eBusiness and EDI systems. The entities registered in the current BSR are not defined in a machine-understandable way, which renders automatic extraction of structural and relationship information from the register impossible. The purpose of this study is to offer a framework for designing an ontology that can provide semantic interoperability among BSR-based systems by defining data structures and relationships with RDF and OWL, similar meaning by the 'equivalentClass' construct in OWL, the hierachical relationships among classes by the 'subClassOf' construct in RDF schema, definition of any entities in BSR by the 'label' construct in RDF schema, specification of usage guidelines by the 'comment' construct in RDF schema, assignment of classes to BSU's by the 'domain' construct in RDF schema, specification of data types of BSU's by the 'range' construct in RDF schema. Hierarchical relationships among properties in BSR can be expressed using the 'subPropertyOf' in RDF schema. Progress in semantic interoperability can be expected among BSR-based systems through applications of semantic web technology suggested in this study.