• 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 the Economic Geographical Society of Korea
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• v.5 no.1
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• pp.5-24
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• 2002

The purpose of this study is to analyze the distribution structure and the logistics system of light petroleum products from the spatial perspectives. The consumption structure of petroleum products has been changed since the mid 1980s. The growth rate of consumption for light products has been much faster than those of heavy products. The distribution structure of the petroleum products is hierarchically established by refining companies, agencies, and gas stations. The petroleum products agencies are distributed unevenly over the country, and the number of gas stations per one petroleum agency are very differentiated by the region. The light products are directly transported from refining factories to oil storages and then are carried to gas stations. According to the locational characteristics, oil storages which play a key role in the logistics system are categorized into three type. The first type is demand-oriented oil storages which are located near or in the large cities to supply the light petroleum products. The second type is harbors-oriented oil storages which are located within harbors. The third type is railway-oriented oil storages which are located along railway stations. In this study, the thresholds of one oil storage and one gas station are calculated based on the size of supply territory for each oil storage. The average number of population demand that allow a oil storage to stay in business is 1.9 million and average number of cars are 477,200.

• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.132-136
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• 2005

It is widely accepted that the reading mechanism of Super-RENS(super-resolution near field structure) and Super-ROM(super-resolution read only memory) is closely related with non-linear temperature dependent material properties such as refractive indices, phase change. Furthermore, the dynamic change of the temperature distribution also an essential part of reading mechanism of Super-RENS/ROM. Therefore, the knowledge of the temperature distribution as a function a time is one of the important keys to reveal the physics of reading mechanism in Super-RENS/ROM. We calculated time-dependent temperature distribution in a 3-dimensional Super-ROM disk structure when moving laser beam is irradiated. With a help of commercial software FEMLAB which employed finite element method, we simulated the temperature distribution of ROM structure whose pit diameter is 120-nm with 50-nm depth. Energy absorption by moving laser irradiation, time variations of heat transfer processes, heat fluxes, heat transfer ratios, and temperature distributions of the complicate 3-dimensional ROM structure have been obtained.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.83-90
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• 1999

This paper presents a method of seismic analysis for a cylindrical liquid storage structure on horizontally layered half-space considering the effects of the interior fluid and exterior soil medium in the frequency domain. the horizontal and rocking motions of the structures are included in this study. The fluid motion is expressed in terms of analytical velocity potential function which can be obtained by solving the boundary value problem including the sloshing behavior of the fluid as well as deformed configuration of the structure. The effect of the fluid is included in the equation of motion as the impulsive added mass and a frequency-dependent convective added mass along the nodes on the wetted boundary with structure. The soil medium is presented using the 3-D axisymmetric finite elements and dynamic infinite elements. The present method can be applied to the structures embedded in ground as well as on ground since it models the soil medium directly as well as the structure. For the purpose of vertification dynamci characteristics of a tank on homogeneous half-space is analyzed. Comparison of the present results with those by others shows good agreement.

• 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.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.275-283
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• 1999

To predict the dynamic behavior of the cylindrical liquid storage tank subjected to seismic ground motion three dimesional analysis with liquid-structure interaction must be performed, In this study a three dimensional dynamic analysis method over the frequency domain using FE-BE coupling technique which combines the efficiency of the boundary elements for liquid with the versatility of the finite shell elements for tank. The liquid region is modeled using boundary elements which can counter the sloshing effect at free surface and the structure region the tank itself is modeled using the degenerated finite shell elements. At the beginning of the procedure the equivalent mass matrix of the liquid is generated by boundary elements procedure. Then this equivalent mass matrix is combined with the mass matrix of the structure to produce the global mass matrix in the equation of the motion of fluid-structure interaction problem In order to demonstrate the accuracy and validity of the developed method the numerical results re compared with the previous studies. Finally the effects of the fluid-structure interaction on the natural frequency and dynamic response of the system are analyzed.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.66-69
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• 2002

This paper proposes a new dynamic storage structure and methods fur geometric data with detail levels. Using geometric data with detail levels, we can search geometric data quickly. However, the previous structures for detail levels form the bottleneck in the design of database and do not support all types of geometric data with detail levels. Our structure supports all types of geometric data with detail levels. Moreover, our structure does not form bottleneck in the design of database. This paper presents the structure and algorithms for searching and updating of geometric data with detail levels. Experiments are then performed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.718-725
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• 2017

A liquid storage tank is one of the most important structures in industrial complexes dealing with chemicals, and its structural damage due to an earthquake may cause a disastrous event such as the leakage of hazardous materials, fire, and explosion. It is thus essential to assess the seismic fragility of liquid storage tanks and prepare for seismic events in advance. When a liquid storage tank is oscillated by a seismic load, the hydrodynamic pressure caused by the liquid-structure interaction increases the stress and causes structural damage to the tank. Meanwhile, the seismic fragility of the structure can be estimated by considering the various sources of uncertainty and calculating the failure probabilities in a given limiting state. To accurately evaluate the seismic fragility of liquid storage tanks, a sophisticated finite element analysis is required during their reliability analysis. Therefore, in this study, FERUM-ABAQUS, a recently-developed computational platform integrated with commercial finite element and reliability analysis software packages, is introduced to perform the finite element reliability analysis and calculate the failure probability of a liquid storage tank subjected to a seismic load. FERUM-ABAUS allows for automatic data exchange between these two software packages and for the efficient seismic fragility assessment of a structure. Using this computational platform, the seismic fragility curve of a liquid storage tank is successfully obtained.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.04b
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• pp.289-296
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• 2000

This paper presents a method of seismic analysis for a 2-D fluid-structure-soil interaction systems. With this method, the fluid can be modeled by spurious free 4-node displacement-based fluid elements which use rotational penalty and mass projection technique in conjunction with the one point reduced integration scheme to remove the spurious zero energy modes. The structure and the near-field soil are discretized by the standard 2-D finite elements, while the unbounded far-field soil is represented by the dynamic infinite elements in the frequency domain. Since this method directly models the fluid-structure-soil interaction systems, it can be applied to the dynamic analysis of a 2-D liquid storage structure with complex geometry. Finally, results of seismic analyses are presented for a spent fuel storage tank embedded in a layered half-space and a massive concrete dam on a layered half-space.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2001.10a
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• pp.132-137
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• 2001

This paper presents a method of seismic analysis for a 2-D fluid-structure-soil interaction systems. With this method, the fluid can be modeled by spurious free 4-node displacement-based fluid elements which use rotational penalty and mass projection technique in conjunction with the one point reduced integration scheme to remove the spurious zero energy modes. The structure and the near-field soil are discretized by the standard 2-D finite elements, while the unbounded far-field soil is represented by the dynamic infinite elements in the frequency domain. Since this method directly models the fluid-structure-soil interaction systems, it can be applied to the dynamic analysis of a 2-D liquid storage structure with complex geometry. Finally, results of seismic analyses are presented for a spent fuel storage tank embedded in a layered half-space and a massive concrete dam on a layered half-space.