• Journal of Digital Contents Society
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• v.8 no.4
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• pp.499-507
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• 2007

With the increasing of users' request about internet web service, importance of Internet datawarehouse to support decision making of users is increasing now. Early Internet datawarehouse was studied in the form of using existent database and XML. However, because of limitation of information expression ability, it is gradually changed to system that use metadata schema like RDFS. Because of distributed environment of the Internet, integration and saving of each metadata schemas into one global schema is important. However, between each different schema, semantic and structural conflicts can be happen in such situation and they must be controlled. In this paper, we analyze occasions of conflict when integrate distributed metadata schemas and propose conflict resolution technique for efficient internet datawarehouse query processing.

• Journal of the Korea Society of Computer and Information
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• v.15 no.1
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• pp.31-42
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• 2010

GPM(Generic Product Model) developed by Hitachi in Japan is a common data model to integrate and share life cycle data of nuclear power plants. GPM consists of GPM core model, an abstract model, implementation language for the model and reference library written in the language. GPM core model has a feature that it can construct a semantic network model consisting of relationships among objects. Initial GPM developed and provided GPML as an implementation language to support the feature of the core model, but afterwards the GPML was replaced by GPM-XML based on XML to achieve data interoperability with heterogeneous applications accessing a GPM data model. However, data models written in GPM-XML are insufficient to be used as a semantic network model for lack of studies which support GPM-XML and enable the models to be used as a semantic network model. This paper proposes OWL as the implementation language for GPM core model because OWL can describe ontologies similar to semantic network models and has an abundant supply of technical standards and supporting tools. Also, OWL which can be expressed in terms of RDF/XML based on XML guarantees data interoperability. This paper uses OWL DL, one of three sublanguages of OWL, because it can guarantee complete reasoning and the maximum expressiveness at the same time. The contents of this paper introduce the way how to overcome the difference between GPM and OWL DL, and, base on this way, describe how to convert the reference library written in GPML into ontologies based on OWL DL written in RDF/XML.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.3
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• pp.15-23
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• 2008

This paper proposes a CIB framework implementing a ubiquitous smart space. In a ubiquitous smart space, a ubiquitous mobile device recognizes surrounding context, and infers the situation and provides services to users. Ubiquitous mobile devices have a RDF store to manage resources and relevant information efficiently on CIB framework. This store space is flexible on the operations such as addition, modification, deletion of information and response to query by SPARQL. In addition, it provides local information to other ubiquitous mobile devices in the from of XML and stores resource information from other ubiquitous mobile devices into local ubiquitous mobile device for the purpose of discovering external resources.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.193-195
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• 2005

OWL facilitates greater machine interpretability of Web content than that supported by XML, RDF, and RDF Schema by providing additional vocabulary along with a formal semantics. We are developing the ontology editor we named OntoBuilder, in this paper we describe about implementation of OWL processor which is a component of OntoBuilder.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.1
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• pp.109-116
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• 2021

Since RDF (Resource Description Framework) triples are modeled as graph, we cannot directly adopt existing solutions in relational databases and XML technology. In order to store, index, and query Linked Data more efficiently, we propose a convergence indexing method combined R*-tree and K-dimensional trees. This method uses a hybrid storage system based on HDD (Hard Disk Drive) and SSD (Solid State Drive) devices, and a separated filter and refinement index structure to filter unnecessary data and further refine the immediate result. We perform performance comparisons based on three standard join retrieval algorithms. The experimental results demonstrate that our method has achieved remarkable performance compared to other existing methods such as Quad and Darq.

• Journal of the Korea Society of Computer and Information
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• v.27 no.9
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• pp.77-89
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• 2022

In this paper, we propose a system which automatically generates SHACL schemas to describe and validate RDF knowledge graphs constructed by RML mappings. Unlike existing studies, the proposed system generates the schemas based on not only RML mapping rules but also metadata extracted from RML mapping input data in various formats such as CSV, JSON, XML or databases. Therefore, our schemas include the constraints on data type, string length, value range and cardinality, which were not present in the existing schemas. And we solves the problem with "repeated properties" which overlooked in existing studies. Through a conformance test consisting of 297 cases, we show that the proposed system generates correct constraints for the graphs. The proposed system can contribute to automation of the tedious and error-prone existing manual validation processes.

• Journal of the Korea Society of Computer and Information
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• v.12 no.1 s.45
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• pp.9-15
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• 2007

As the information of the internet increased, importance of sematic web for collecting and integration of these informations to support decision making of some group or ordinary people are growing as well. Basis structure that composes semantic web is ontology and languages like XML, RDF/RDF schema and OWL are basis means that compose ontology schema. When composes and manages Ontology schema, one of the important consideration point is that schema is changed as times go by. Therefore, change of domain of schema, change of data concept or change of relation between resource etc. are reflected in the ontology system. In this study, we suggest semantic web schema management skill in terms of version management. We categorized version change forms and created version graph for checking of version transition. With created version graph, we define transitivity rule and propose schema tag for detail application which enables extending of applicable version schema.

• Journal of the Korea Society of Computer and Information
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• v.27 no.11
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• pp.67-80
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• 2022

In this paper, we propose a system which automatically generates the ShEx schemas to describe and validate RDF knowledge graphs constructed by RML mapping. ShEx schemas consist of constraints. The proposed system generates most of the constraints by converting the RML mapping rules. The schemas consisting only of constraints obtained from mapping rules can help users to figure out the structure of the graphs generated by RML mapping, but they are not sufficient for sophisticated validation purposes. For users who need a schema for validation, the proposed system is also able to provide the schema with added constraints generated from metadata extracted from the input data sources for RML mapping. The proposed system has the ability to handle CSV, XML, JSON or RDBMS as input data sources. Testing results from 297 cases show that the proposed system can be applied for RDF graph validation in various practical cases.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10e
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• pp.208-210
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• 2002

웹의 이용이 보편화되면서 웹 상의 자원(Resource) 또한 급격히 증가하고 있다. 이러한 상황에서 웹 자원을 효율적으로 기술할 수 있는 RDF(Resource Description Framework)는 웹 자원을 체계적으로 관리할 수 있는 지평을 열어주었다. 그러나 현재 RDF문서의 저작환경은 저차원적인 텍스트 편집 수준으로 파싱(parsing)과 유효성 검사(validation checking)를 지원하지 못하고 있는 실정이다. 따라서 본 논문에서는 저작환경을 개선함과 동시에 RDF 및 XML 문서에 대한 파싱 및 유효성 검사를 효율적으로 수행하고, RDF로 기술된 웹 자원을 n-triple 형식으로 생성할 수 있는 RDF 저작 툴을 설계 및 구현하여 유효성이 보장된 웹 자원을 효율적으로 생성 및 처리할 수 있도록 하였다.

• Journal of Information Management
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• v.34 no.3
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• pp.87-109
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• 2003

Continual attempts to accumulate and apply information eventually gave birth to the concept of the "Semantic Web". Thus, the "Semantic Web" can be defined as a product of mankind's desire to standardize information. At the same time, the term provides "a method that standardizes mankind's concept of linguistical expression", and can be noted as an effort to combine such methods into a standard web environment that may materialize to form a catalogue. This study introduced RDF schema, ontology languages for the semantic web, and ontology-based systems. The purpose of the study was to construct a system based on the semantic web environment's ontology by utilizing the ontology schema derived from the facettype Art and Architecture Thesaurus(AAT). The aforementioned ontology schema is based on the Web Ontology Language(OWL), which is being widely considered the standard ontology language for the W3C-centered semantic web environment.