• The Journal of Society for e-Business Studies
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• v.12 no.3
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• pp.251-268
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• 2007

We design and implement an efficient storage technique to improve query processing for a large RDF data set. The proposed techniques can minimize data redundancy compared to the existing techniques by splitting relation information and data information from triple formatted RDF data. Also, we can enhance query processing speed separating and connecting the entire query steps by relation and data based on the proposed storage technique. The proposed technique can be applied to the areas, such as e-Commerce, semantic web, and KMS to store and retrieve a large RDF data set.

• Journal of KIISE:Databases
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• v.35 no.3
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• pp.243-256
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• 2008

With rapid growth of Internet, the amount of information in the Web is increasing exponentially. However, information on the current Web is understandable only for human, and thus it makes the exact information retrieval difficult. For solving this problem, the Semantic Web is suggested and we must use ontology languages that can endow data to semantics for implementing it. One of the representative ontology languages is OWL(Web Ontology Language) adopted as a recommendation by the World-Wide Web Consortium. OWL has richer expression power and formal semantics than other ontology languages such as RDF and RDF-S. In addition, OWL includes hierarchical structure information between classes or properties. Therefore, an efficient OWL storage model considering hierarchical structure for effective information retrieval on the Semantic Web is required. In this paper, we suggest the XPOS(XPath-based OWL Storage) model including hierarchy information between classes or properties as XPath form and enabling intuitive and effective information retrieval. Also, we show the comparative evaluation results on the performance of XPOS model, Sesame, and the XML storage-based storage model regarding query processing.

• 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.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07b
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• pp.217-219
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• 2005

정보의 단순한 연결을 표현하는 현재 웹 환경의 한계를 보완하기 위해 차세대 웹으로서 평가되고 있는 시맨틱 웹에서는 정보 리소스의 의미와 개념적 관계를 정의하는 메타데이터와 온톨로지의 역할이 무엇보다 중요시되고 있다. 따라서 RDF와 RDF 스키마와 같은 표준 언어로써 표현되는 메타데이터와 온톨로지의 효과적인 저장과 검색의 방법이 필요하다. RDF와 RDF 스키마는 그래프 모델로서 표현이 가능하고 다양한 질의의 형태가 그래프 형태에서 추출 가능한 경로 형식으로 표현들 수 있기 때문에 보다 효율적인 질의 처리를 위해서는 경로 정보의 저장에 대한 연구가 필요하다. 따라서 본 논문에서는 관계형 데이터베이스를 기반으로 RDF와 RDF 스키마의 기본적인 정보와 특정 클래스, 프로퍼티, 리소스로 시작하는 경로 정보를 함께 저장할 수 있는 저장 구조를 제안한다.

• Journal of the Korea Computer Industry Society
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• v.7 no.3
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• pp.227-236
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• 2006

Semantic Web is getting popular to next web environment. Additionally, ontology language research is also activating to represent semantic relation of resource in semantic web. Specially, Ontology language as RDF and DAML+OIL appear on start point of research. But Ontology Language limited to describing characters of resource and to making a clear definition of relation of resource. So W3C suggest OWL at the next standard language for describing resource. OWL supply the lack of representation for RDF and RDF Schema. In this paper, we make Ontology to implement Online Retrieval System using OWL and propose the structure of storing Ontology document at the RDB. The structure support characters of OWL that are equivalent relationship, heterogeneous relationship, inverse relationship, union relationship and one of relationship between classes or properties. In this paper, we classify the extended elements for OWL from RDF Schema. And we propose the method of storing OWL using RDB for interoperability with many applications based on RDB. Finally, implement the storage and retrieval system based on OWL to provide advanced search function.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.45-52
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• 2020

This paper proposes a solution for storage and retrieval problems for Resource Description Framework (RDF) data utilizing a key-value Solid State Device (SSD), considering storage, retrieval performance, and security. We propose a two-step compression algorithm to separate logical relationship and true values from RDF data-sets using the key-value SSD. This improves not only compression and storage efficiency but also storage security. We also propose a hybrid retrieval structure based on R∗-tree to enhance retrieval efficiency and implement a sort-merge join algorithm, and discuss factors affecting R∗-tree retrieval efficiency. Finally, we show the proposed approach is superior to current compression, storage, and retrieval approaches, obtaining target results faster while requiring less space, and competitive in terms of versatility, flexibility and security.

• 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.

• The Journal of Society for e-Business Studies
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• v.13 no.3
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• pp.85-101
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• 2008

The semantic web is taken as next generation standards of information exchange on the internet to overcome the limitations of the current web. To utilize the information on the semantic web, tools are required the functionality of query search and reasoning for the ontology. However, most of semantic web management tools cannot efficiently support the search for the complex query because they apply Triple-based storage structure about RDF metadata. We design the storage structure of the ontology in corresponding with the structure of ontology data and develop the search system(SMART-DLTriple) to support complex query search efficiently in this research. The performance of the system using new storage structure is evaluated to compare with the popular semantic web management systems. The proposed method and system make a contribution to enhancement of a practical ontology reasoning systems due to improved performance of the ontology search.

• Journal of the Korea Society of Computer and Information
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• v.12 no.5
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• pp.93-102
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• 2007

Metadata and ontology can be used to retrieve related information through the inference mure accurately and simply on the Semantic Web. RDF and RDF Schema are general languages for representing metadata and ontology. An enormous number of keywords on the Semantic Web are very important to make practical applications of the Semantic Web because most users prefer to search with keywords. In this paper, we consider a resource as a unit of query results. And we classily queries with keyword conditions into three patterns and propose indexing techniques for keyword-search considering both metadata and ontology. Our index maintains resources that contain keywords indirectly using conceptual relationships between resources as well as resources that contain keywords directly. So, if user wants to search resources that contain a certain keyword, all resources are retrieved using our keyword index. We propose a structure of table for storing RDF Schema information that is labeled using some simple methods.

• Journal of the Korean Institute of Gas
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• v.5 no.4 s.16
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• pp.40-48
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• 2001

For a Liquified Petroleum Gas(LPG) station, the reliability analysis, such as Fussell-Vesely importance, risk decrease factor and risk increase factor, was carried out and the risk ranks of events were determined. In order to confirm the degree of the risks identified in the reliability analysis, the quantitative risk analysis was done for the equipments which had the large values of risk ranks. As a result of the importance analysis for the LPG station, the external event was identified as the most riskful event. The defect of construction structure and the pipe corrosion were riskful as well. The result of quantitative risk analysis showed that the length of 46.3 meters were estimated to damage the process equipments by the thermal flux from the catastrophic rupture of storage tank in Boiling Liquid Expanding Vapor Explosion.