• Communications of the Korean Mathematical Society
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• v.18 no.2
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• pp.207-214
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• 2003

There exist two distinct Symmetric differences in a non Boolean orthomodular lattics. Let L be an orthomodular lattice. Then L is a Boolean algebra if and only if one symmetric difference is equal to the other. An orthomodular lattice L is Boolean if and only if one of two symmetric differences of L is associative.

• Journal of Korean Society of Steel Construction
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• v.11 no.2 s.39
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• pp.117-129
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• 1999

The objective of this study is to identify the advantages of composite materials and to investigate the behavior of the anisotropic symmetric laminated cylindrical shell structures. To analyze the anisotropic symmetric laminated cylindrical shell structures, the finite difference technique. that consists of forward, central and backward difference, is introduced. In this study, the degree of freedom consists of three displacements and, especially, two moments except twisting moment. It has the advantage of improving the accuracy for calculating the moments. All four edges are assumed to be simply supported. From the numerical results, it is proved that the finite difference technique can be used efficiently to analyze the anisotropic symmetric laminated cylindrical shells and gives a guide in deciding how to make use of the fiber angle the anisotropic symmetric laminated cylindrical shells.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.1
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• pp.75-81
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• 2018

Purpose : The aim of this study was to compare the muscle activities of thumb and wrist during unimanual, bimanual symmetric and bimanual reciprocal movements using surface electromyography. Method : Thirty-six participants were involved in this study. Two blocks were used to perform unimanual, bimanual symmetric and bimanual reciprocal movements of thumb and wrist. Muscle activities in the flexor pollicis brevis, abductor pollicis brevis, extensor carpi radialis and flexor carpi radialis were measured using an surface EMG system. Result : For the flexor pollicis brevis and abductor pollicis brevis, significant difference in the muscle activity were found among the unimanual, bimanual symmetric and bimanual reciprocal movement. For the extensor carpi radialis and flexor carpi radialis, the unimanual movement significantly different from the bimanual symmetric and reciprocal movements. Conclusion : Both the thumb and wrist, bimanual symmetric and reciprocal movements were more efficient than the unimanual movement. Moreover, with regard to the thumb, the bimanual reciprocal movement was more efficient than the bimanual symmetric movement.

• The Mathematical Education
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• v.49 no.4
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• pp.489-500
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• 2010

This study makes clear justification of contents of set in secondary school through the scientific consideration and contents consideration of curriculum about two points - lattice and ring - of set deal with 'number and operation'. In this process, we make clear the greatest common divisor, the least common multiple and operation of set, especially the meaning of symmetric difference, we suggest direction about constitution of contents of set in secondary school. This study helps to raise the specificity on the elements of textbook and presents the first step about the range of teaching in a construct of curriculum.

• Communications for Statistical Applications and Methods
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• v.13 no.1
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• pp.125-134
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• 2006

This study confirms that the regression model of endpoint of interval outputs is not identical with that of the other endpoint of interval outputs in interval regression models proposed by Tanaka et al. (1987) and constructs interval regression models using the best regression model given by variable selection. Also, this paper suggests a method to minimize the sum of lengths of a symmetric difference among observed and predicted interval outputs in order to estimate interval regression coefficients in the proposed model. Some examples show that the interval regression model proposed in this study is more accuracy than that introduced by Inuiguchi et al. (2001).

• Communications of the Korean Mathematical Society
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• v.9 no.2
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• pp.439-448
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• 1994

It is known that the steepest descent(SD) method and the conjugate gradient(CG) method [1, 2, 5, 6] converge when these methods are applied to solve linear systems of the form Ax = b, where A is symmetric and positive definite. For some finite difference discretizations of elliptic problems, one gets positive definite matrices that are almost symmetric. Practically, the SD method and the CG method work for these matrices. However, the convergence of these methods is not guaranteed theoretically. The SD method is also called Orthores(1) in iterative method papers. Elman [4] states that the convergence proof for Orthores($\kappa$), with $\kappa$ a positive integer, is not heard. In this paper, we prove that the SD method and the CG method converge when the $\iota$$^2$ matrix norm of the non-symmetric part of a positive definite matrix is less than some value related to the smallest and the largest eigenvalues of the symmetric part of the given matrix.(omitted)

• Journal of the Korea Institute of Military Science and Technology
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• v.4 no.2
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• pp.122-129
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• 2001

A characterization procedure for analyzing symmetric coupled MIS(Metal-Insulator-Semiconductor) transmission line is used the same procedure as a general single layer symmetric coupled line with perfect dielectric substrate from the extraction of the characteristic impedance and propagation constant for even- and odd-mode. In this paper, an analysis for a new substrate shielding symmetric coupled MIS structure consisting of grounded crossbar at the interface between Si and SiO2 layer using the Finite- Difference Time-Domain(FDTD) method is presented. In order to reduce the substrate effects on the transmission line characteristics, a shielding structure consisting of grounded crossbar lines over time-domain signal has been examined. Symmetric coupled MIS transmission line parameters for even- and odd-mode are investigated as the functions of frequency, and the extracted distributed frequency- dependent transmission line parameters and corresponding equivalent circuit parameters as well as quality factor for the new MIS crossbar embedded structure are also presented. It is shown that the quality factor of the symmetric coupled transmission line can be improved without significant change in the characteristic impedance and effective dielectric constant.

• Journal of Mechanical Science and Technology
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• v.18 no.9
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• pp.1559-1564
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• 2004

The process design of hot forging, asymmetric to symmetric rib-web shaped steel, which is used for the turnout of express rails has been studied. Owing to the great difference in shape between the initial billet and the final forged product, it is impossible to hot forge the rail in a single stage operation. The numerical simulation for hot forging of asymmetric shape to symmetric shape was carried out by using commercial FEM code, DEFORMTM-2D. For comparison with the simulation results, a experiment of flow analysis using plasticine was also carried out. The results of the flow experiment showed good agreement with those of the simulation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.187-190
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• 2004

Transducer for ultrasonic linear motor with the symmetric and anti-symmetric modes was studied. The ultrasonic liner motor consists of two Lngevin type piezoelectric vibrators that cross at right angles with each other in tip. In order to excite symmetric and anti-symmetric mode, the transducer must have a 90 degree phase difference of voltage. Therefore, the tip of transducer moves on an elliptical motion. In this paper, the finite element analysis was used. The ultrasonic motor was fabricated using the simulated result and the driving characteristics were measured.

• Communications of the Korean Mathematical Society
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• v.9 no.1
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• pp.79-87
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• 1994