• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.3
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• pp.191-198
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• 2014

During multi-physics or multi-phase simulations accompanying fluid- structure- thermal interaction, data transfer problems always arise along non- matching interfaces caused by different computational meshes for each physical domain. Common- refinement scheme, among many available methods, is attractive since it is known to yield conservative and accurate data transfer for non- matching interface cases. This is particularly important in simulating compressible unsteady fluid- structure- thermal interaction inside solid propellant rockets, where grid size along solid- fluid interfaces is substantially different. From this perspective, we examine performances of common- refinement- based data transfer scheme between structured quadrilateral (structure part) and unstructured triangular (fluid part) meshes by comparing computed results with other data transfer methods.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.3
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• pp.331-340
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• 2010

The basic theory and application of new adaptive finite element algorithm have been proposed in this study including the adaptive hp-refinement strategy, and the effective method for constructing hp-approximation. The hp-adaptive finite element concept needs the integrals of Legendre shape function, nonuniform p-distribution, and suitable constraint of continuity in conjunction with irregular node connection. The continuity of hp-adaptive mesh is an important problem at the common boundary of element interface. To solve this problem, the constraint of continuity has been enforced at the common boundary using the connectivity mapping matrix. The effective method for constructing of the proposed algorithm has been developed by using hierarchical nature of the integrals of Legendre shape function. To verify the proposed algorithm, the problem of simple cantilever beam has been solved by the conventional h-refinement and p-refinement as well as the proposed hp-refinement. The result obtained by hp-refinement approach shows more rapid convergence rate than those by h-refinement and p-refinement schemes. It it noted that the proposed algorithm may be implemented efficiently in practice.

• Journal of the Korea Convergence Society
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• v.9 no.12
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• pp.9-15
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• 2018

The main goal of extended data expression is to develop a data structure suitable for common problems in ubiquitous environments. The greatest feature of this method is that the attribute values can be represented with probability. The next feature is that each event in the training data has a weight value that represents its importance. After this data structure has been developed, an algorithm has been devised that can learn it. In the meantime, this algorithm has been applied to various problems in various fields to obtain good results. This paper first introduces the extended data expression technique, UChoo, and rule refinement method, which are the theoretical basis. Next, this paper introduces some examples of application areas such as rule refinement, missing data processing, BEWS problem, and ensemble system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.07a
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• pp.286-287
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• 2020

Depth map is the most common way of expressing 3D space in immersive media. In this paper, we propose a post-processing method to improve the quality of depth map. In proposed method, a depth map is divided into segments, and the plane of each segment estimated using RANSAC. In order to increase the accuracy of the RANSAC process, we apply matching reliability of each pixel in depth map as a weighting factor.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.271-274
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• 2007

The finite element linear buckling analysis of folded plate structures using adaptive h-refinement methods is presented in this paper. The variable-node flat shell element used in this study possesses the drilling D.O.F. which, in addition to improvement of the element behavior, permits an easy connection to other elements with six degrees of freedom per node. The Box-typed structures can be analyzed using these developed flat shell elements. By introducing the variable node elements some difficulties associated with connecting the different layer patterns, which are common in the adaptive h-refinement on quadrilateral mesh, can be overcome. To obtain better stress field for the error estimation, the super-convergent patch recovery is used. The convergent buckling modes and the critical loads associated with these modes can be obtained.

• Journal of Information Technology and Architecture
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• v.9 no.4
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• pp.357-363
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• 2012

Ontologies are being used in order to define common vocabularies to describe the elements of schemas involved in a particular application. The problem of finding correspondences between ontologies concepts, called ontology matching, consists in the discovery of correspondences between terms of vocabularies (represented by ontologies) used by various applications. The majority of solutions proposed in the literature, despite being fully automatic, has heuristic nature and may produce nonsatisfactory results. The problem intensifies when dealing with large data sources. The goal of this paper is to propose a method for generation and incremental refinement of correspondences between ontologies. The proposed approach uses filtering techniques, as well as user feedback to support the generation and refinement of such matches. For validation purposes, a tool was developed and some experiments were conducted.

• Nuclear Engineering and Technology
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• v.48 no.2
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• pp.470-481
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• 2016

Field-programmable gate arrays (FPGAs) have received much attention from the nuclear industry as an alternative platform to programmable logic controllers for digital instrumentation and control. The software aspect of FPGA development consists of several steps of synthesis and refinement, and also requires verification activities, such as simulations that are performed individually at each step. This study proposed an integrated software-testing framework for simulating all artifacts of the FPGA software development simultaneously and evaluating whether all artifacts work correctly using common oracle programs. This method also generates a massive number of meaningful simulation scenarios that reflect reactor shutdown logics. The experiment, which was performed on two FPGA software implementations, showed that it can dramatically save both time and costs.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.20 no.3
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• pp.265-272
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• 2007

The finite element linear buckling analysis of folded plate structures using adaptive h-refinement methods is presented in this paper. The variable-node flat shell element used in this study possesses the drilling D.O.F. which, in addition to improvement of the element behavior, permits an easy connection to other elements with six degrees of freedom per node. The Box-typed structures can be analyzed using these developed flat shell elements. By introducing the variable-node elements some difficulties associated with connecting the different layer patterns, which are common in the adaptive h-refinement on quadrilateral mesh, can be overcome. To obtain better stress field for the error estimation, the super-convergent patch recovery is used. The convergent buckling modes and the critical loads associated with these modes can be obtained.

• Journal of the Korean Society of Food Culture
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• v.19 no.4
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• pp.378-391
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• 2004

The Korean tea culture appeared in a variety of ceremonies of the royal household. It was a method of religion for scholars and Buddhist monks, and sometimes it also was a refinement, too. in addition, it played an important role as a household medicine for the common people. As mentioned above, the Korean tea culture has a deep-rooted effect on the Korean traditional culture from the spiritual aspect, art, learning, to the practical life. Recently the tea culture has been rapidly coming into vogue. So the tea culture has been recognised not only to be an index of the cultural level, but also to be an important cultural phenomenon. Besides, It came to be a major role as a reception method by which we can communicate with quests from ail over the world. Because preferred tea was different according to the times and to the regions, tea utensils have been changed along with the tea culture. The present Korean tea culture has a tendency to go to the somewhat different way from the traditional one. This study has the purpose to let us apprehend the Korean traditional culture and hold the national pride. In addition, the value of the Tea should be assessed more properly, and our own Tea that is unique, simple, and natural, should be settled in the our culture.

• Journal of Mechanical Science and Technology
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• v.16 no.9
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• pp.1054-1064
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• 2002

Numerical prediction of welding-induced residual stresses using the finite element method has been a common practice in the development or refinement of welded product designs. Various researchers have studied several thermal models associated with the welding process. Among these thermal models, ramp heat input and double-ellipsoid moving source have been investigated. These heat-source models predict the temperature fields and history with or without accuracy. However, these models can predict the thermal characteristics of the welding process that influence the formation of the inherent plastic strains, which ultimately determines the final state of residual stresses in the weldment. The magnitude and distribution of residual stresses are compared. Although the two models predict similar magnitude of the longitudinal stress, the double-ellipsoid moving source model predicts wider tensile stress zones than the other one. And, both the ramp heating and moving source models predict the stress results in reasonable agreement with the experimental data.