• Structural Engineering and Mechanics
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• v.29 no.2
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• pp.117-134
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• 2008

A new adaptive dual reciprocity boundary element method for dynamic analysis of 3-D structures is presented in this paper. It is based on finding the best approximation function of a radial basis function (RBF) group $f=r^n+c$ which minimize the error of displacement field expansion. Also, the effects of some parameters such as the existence of internal points, number of RBF functions and position of collocation nodes in discontinuous elements are investigated in this adaptive procedure. Three numerical examples show improvement in dynamic response of structures with adaptive RBF in dual reciprocity with respect to ordinary BEM.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.2
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• pp.107-113
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• 2013

When the main spindle of high precision machine tools are run many hours, heat is generated in bearing parts of the inside of the spindle. Also, headstock is appeared distortion by inside and outside temperature difference of a machine. This paper studies method to measure behavior of machine tool about these thermal effects. In addition, it estimates measurement uncertainty factors which can be appeared in thermal effects measurement. Finding the factor of thermal affect measurement is important for estimation of measurement uncertainty. This paper measures thermal effects of high precision machine tools and evaluates the important factors of uncertainty.

• International Journal of Reliability and Applications
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• v.8 no.2
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• pp.137-151
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• 2007

Posbist reliability of typical systems is preliminarily discussed in Cai (1991). In this paper, we focus on the posbist reliability analysis of some typical systems in depth. First, the lifetime of the system is dealt as a fuzzy variable defined on the possibility space (U, ${\phi}$, $P_{oss}$) and the universe of discourse is expanded from (0, $+{\infty}$) to ($-{\infty},\;+{\infty}$). Then, a concrete possibility distribution function of the fuzzy variable is given, i.e., a Gaussian fuzzy variable. Finally, posbist reliability of typical systems (series, parallel, series-parallel, parallel-series, cold redundant system) is deduced. The expansion makes the proofs of some theorems straightforward and allows us to easily obtain the posbist reliability of typical systems. To illustrate the method a numerical example is given.

• Journal of the Korean Society of Propulsion Engineers
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• v.5 no.3
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• pp.1-9
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• 2001

Impact tests are performed on the high strength structural steel that is being developed for the submarine material. Especially, the impact characteristics of this structural steels at low temperatures are investigated by charpy impact testing. Hyperbolic tangent curve fitting method is used to evaluate the LSE(lower shelf energy), USE(upper shelf energy) and DBTT(ductile-brittle transition temperature). Proportional equations between charpy impact energy and lateral expansion are obtained using the test results. Effect of temperature on the fracture appearance is investigated by using SEM.

• International Journal of Aerospace System Engineering
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• v.2 no.2
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• pp.62-66
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• 2015

The starting processes of the Ludwieg tube hypersonic quiet tunnel plays very important role in the achievement of the quiet flow in the test section, which could affect the confidence coefficient of the data in the hypersonic transition experimental investigations. Thus, numerical analysis on that processes could help to understanding the running mode of the Ludwieg tube quiet tunnel and the propagation principle of the expansion wave series. To verify our computational method, the same parameter of the BAM6QT (the Boeing/AFOSR Mach-6 quiet tunnel at Purdue University) is used to compute, and it is agrees with our computational results.

• Journal of Sasang Constitutional Medicine
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• v.12 no.2
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• pp.43-55
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• 2000

Purpose This study is intended to catch the expansion of theory of Sasang Constitutional Medicine through comparison prescription of Sasang-Yihak-Chobonguen with prescription of Dongyi-Soose-Bowon Method I studied the archive of prescription and medicines concerned in the Sasang-Yihak- Chobonguen with Dongyi-Soose-Bowon Result and conclusion 1. The base of theory on prescription of Sasang-Yihak-Chobonguen is based on Naesang -oigam theory but the base of theory on prescription of Dongyi-Soose-Bowon is based on Pyoribyung theory of Sasang constitutional Medicine. 2. Medicines are confused in prescription of Sasang-Yihak-Chobonguen but medicines are not confused in prescription.

• International Commerce and Information Review
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• v.6 no.1
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• pp.267-284
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• 2004

The expansion of regionalism has resulted in the creation of blocs of the world economy, so that those countries not belonging to one or more blocs can discriminated. Though recently singed on the bill of FTA with Chile, Korea is actually alienated from major stream of the blocs. Therefore, Korea government makes efforts to contract more FTAs with countries such as Singapore and Japan. FTA is believed to be an important method to secure export and national competitiveness in the long term. Therefore, we need to exactly understand critical issues and the long-run effect of FTA. The paper tries to find out important issues and potential strategies relating to electronic commerce in Korea-Singapore and Korea-Japan FTA. According to the historical facts, economic effect of FTA depends a lot on the contents of the agreement. Therefore, additional intensive studies are required before contracting FTA in the future.

• International Commerce and Information Review
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• v.8 no.1
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• pp.227-242
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• 2006

The rapid expansion of regionalism has resulted in the creation of blocs of the global economy, so that those countries not belonging to one or more blocs can be discrimiated. Though signed on the bill of FTA with Chile, Korea is actually alienated from major stream of the blocs. Therefore, Korea government makes efforts to contract more FTAs with countries such as Singapore and Japan, others. FTA is believed to be an important method to secure export and national competitiveness. Therefore, we need to exactly understand critical issues and the long-run effort of FTA. This paper tries to find out important issues and potential strategies relating to electronic commerce in Korea's FTA with other countries. In these means, relationship between FTA and e-Trade are closely related to global business chance. In these means, we should use FTA potentials for encouraging global commerce by e-Trade and develop e-FTA in the foreseeable future.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.375-376
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• 2007

This paper proposes an algorithm for rejecting mismatched points (known as outliers). The proposed algorithm identifies and rejects outliers in image pairs obtained under automobile-like motions which consist of two translations and one rotation. The camera rotation is approximated to the image shift by assuming that the narrow field of lens is used. The voting method estimates the focus of expansion (FOE) while shifting one of the images. Using the properties of the FOE, the outliers are rejected while most of the inliers are retained.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.04a
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• pp.415-429
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• 2002

Various modeling techniques for ultrasonic wave propagation and scattering problems in finite solid media are presented. Elastodynamic boundary value problems in inhomogeneous multi-layered plate-like structures are set up for modal analysis of guided wave propagation and numerically solved to obtain dispersion curves which show propagation characteristics of guided waves. As a powerful modeling tool to overcome such numerical difficulties in wave scattering problems as the geometrical complexity and mode conversion, the Boundary Element Method(BEM) is introduced and is combined with the normal mode expansion technique to develop the hybrid BEM, an efficient technique for modeling multi-mode conversion of guided wave scattering problems.