• Honam Mathematical Journal
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• v.41 no.3
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• pp.505-514
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• 2019

In this paper, some results are obtained from studying convolution on the spectrum of full transformation semigroup and some of its subsemigroups using Cayley's table. The shift of ${\alpha}$ determines its eigenvalues and one-dimensional linear convolution is complex in Symmetric group.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.5
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• pp.353-358
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• 2020

In the case of a general spiral inductor, the orientation of the port is affected as it has an asymmetric structure. In this paper, a single-layered spiral inductor that can have a symmetrical structure is proposed, and the simulation and frequency characteristics are analyzed. The general spiral inductor shows a large difference in frequency-inductance characteristics, frequency-quality factor characteristics, and self-resonant frequency according to the standard of the port, while the proposed symmetric spiral inductor has an inductance of 2.7nH, a quality factor of about 7.86, and a self-resonant frequency of about 14.1GHz without changing the port. Compared to the general spiral inductor having a large difference depending on the port, it was confirmed that the influence on the port direction was small. However, it was confirmed that the mutual inductance decreased compared to the occupied area of the coil, resulting in a low inductance, and the resistance of the coil increased more than the increase in the inductance, and the quality factor was also lowered. In the future, it is expected that inductance and quality factor can be improved through a 2-layer symmetrical spiral structure.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.1
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• pp.152-157
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• 2003

Process design of hot forging, asymmetric to symmetric rib-web shape steel, which is used for the turnout of railway express has been investigated. Owing to the big difference in shape between the initial billet and the final forged product, it is impossible to hot forge the rail in a single step. Therefore, multi step forging as well as die design for each step are necessary for the production. The deformation behavior during hot forging has been analyzed by the numerical simulation through commercial FEA software, $DEFORM^{TM}$-2D. Modification of the design and repeated simulation have been carried out on the basis of the simulation result. For comparison with the simulation results. flow analysis experiment using plasticine has been also carried out. The results of the flow analysis experiment showed good agreement with those of the simulation. Therefore, the developed process design could be applied to the actual production.

• International Journal of Aeronautical and Space Sciences
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• v.12 no.1
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• pp.84-91
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• 2011

A finite element analysis for the wing and landing gear of a composite target-drone air vehicle was performed. For the wing analysis, two load cases were considered: a 5g symmetric pull-up and a -1.5g symmetric push-over. For the landing gear analysis, a sinking velocity of 1.4 m/s at a 2g level landing condition was taken into account. MSC/NASTRAN and LS-DYNA were utilized for the static and dynamic analyses, respectively. Finite element results were verified by the static test of a prototype wing under a 6g symmetric pull-up condition. The test showed a 17% larger wing tip deflection than the finite element analysis. This difference is believed to come from the material and geometrical imperfections incurred during the manufacturing process.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.3
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• pp.1167-1187
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• 2020

With the development of medical imaging technology, image registration has been widely used in the field of disease diagnosis. The registration between different modal images of brain magnetic resonance (MR) is particularly important for the diagnosis of brain diseases. However, previous registration methods don't take advantage of the prior knowledge of bilateral brain symmetry. Moreover, the difference in gray scale information of different modal images increases the difficulty of registration. In this paper, a multimodal medical image registration method based on image segmentation and symmetric self-similarity is proposed. This method uses modal independent self-similar information and modal consistency information to register images. More particularly, we propose two novel symmetric self-similarity constraint operators to constrain the segmented medical images and convert each modal medical image into a unified modal for multimodal image registration. The experimental results show that the proposed method can effectively reduce the error rate of brain MR multimodal medical image registration with rotation and translation transformations (average 0.43mm and 0.60mm) respectively, whose accuracy is better compared to state-of-the-art image registration methods.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.5 no.2
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• pp.63-69
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• 2001

In this study, we shall be concerned with computing in parallel a few of the smallest eigenvalues and their corresponding eigenvectors of the eigenvalue problem, $Ax={\lambda}Bx$, where A is symmetric, and B is symmetric positive definite. Both A and B are large and sparse. Recently iterative algorithms based on the optimization of the Rayleigh quotient have been developed, and CG scheme for the optimization of the Rayleigh quotient has been proven a very attractive and promising technique for large sparse eigenproblems for small extreme eigenvalues. As in the case of a system of linear equations, successful application of the CG scheme to eigenproblems depends also upon the preconditioning techniques. A proper choice of the preconditioner significantly improves the convergence of the CG scheme. The idea underlying the present work is a parallel computation of the Multi-Color Block SSOR preconditioning for the CG optimization of the Rayleigh quotient together with deflation techniques. Multi-Coloring is a simple technique to obatin the parallelism of order n, where n is the dimension of the matrix. Block SSOR is a symmetric preconditioner which is expected to minimize the interprocessor communication due to the blocking. We implemented the results on the CRAY-T3E with 128 nodes. The MPI(Message Passing Interface) library was adopted for the interprocessor communications. The test problems were drawn from the discretizations of partial differential equations by finite difference methods.

• Metals and materials international
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• v.24 no.6
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• pp.1369-1375
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• 2018

In Fe-3%Si steel, the hot rolling process affects not only the hot rolling texture but also the primary recrystallization texture. Here, the effect of asymmetric hot rolling was studied by comparing the difference in the texture evolved between asymmetric and symmetric hot rolling. The effect of asymmetric hot rolling on the texture of primary recrystallized Fe-3%Si steel was also studied. The symmetric hot rolling of Fe-3%Si steel produces a rotated cube texture at the center but Goss and copper textures near the surface. Asymmetric hot rolling tends to produce Goss and copper textures even at the center like the texture near the surface. After primary recrystallization, the dominant texture at the center changes from {001} <210> to {111} <112> and the new texture has a higher fraction of the grains which make the low energy boundary with Goss grains than that of symmetric hot rolling.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.15 no.5
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• pp.315-320
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• 2022

In the case of a general spiral inductor, the orientation of the port is affected as it has an asymmetric structure. In this paper, double-layer spiral inductor that can have a symmetrical structure is proposed, and the simulation and frequency characteristics are analyzed. Compared to the conventional single-layer symmetrical inductor having an inductance of 3.9~4.2nH, the proposed double-layer symmetric spiral inductor has an inductance of 11~12nH in 0.3~1.2GHz frequency range, a quality factor of about 4.4 in 800MHz, and a self-resonant frequency of about 2.7~2.8GHz without changing the port. Compared to the general spiral inductor having a large difference depending on the port, it was confirmed that the influence on the port direction was small.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.87-90
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• 1989

The force acting on high Tc superconductors at 77K is measured and analyzed numerically. Both values are compared, and the difference between them is discussed. The forces, acting on a superconducting disk (thickness:1[mm], diameter:12[mm]) in an axially-symmetric magnetic field produced by a solenoid or a permanent magnet ring, are measured at 77K. The disk is an YBCO high Tc superconductor. The discrete surface current method(DSCM) is formalized for an axially-symmetric magnetic field. The forces of the superconducting disk in the magnetic field are analyzed using the DSCM, assuming that the disk is a perfect diamagnetic body. When the bottom side of the disk is separated 8[mm] from the top side of the solenoid, and the magnetic field applied on the center of the bottom side of the disk is 96[G], the measured value and the calculated value of the force are 96 and 496[mgf], respectively. The difference between them is caused by a non-perfect diamagnetism of the high Tc superconductor at 77K. It is proposed that a real force acting on high Tc superconductors at 77K can be estimated on the basis of a measured magnetic susceptibility of the high Tc superconductor at 77K and a calculated force of a perfect diamagnetic body.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.230-231
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• 2011

There is a merit a planetary gear set disperses a delivery load, and to decrease loss of friction and noise. But, in addition to meshing this internal and external gear simultaneously and phase difference by the tooth contact point and the time difference occurs asymmetric and symmetric sideband noise and vibration caused by the modulation in the vehicle. Existing planetary gear set research have progressed to reduce the cause of the sideband as run-out, pitch error and imbalance. In this paper presents a method for the design of the carrier phase difference by developing various theorys and experiments for gear noise.