• Bulletin of the Society of Naval Architects of Korea
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• v.21 no.3
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• pp.43-50
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• 1984

A body form, which experiences minimum vertical wave-exciting forces in the vicinity of a prescribed wave frequency in water of finite depth, is obtained by an approximate method. Its configuration has the symmetry with respect to the vertical axis, expressed in terms of exponential functions. By distributing three-dimensional pulsating sources and dipoles on the immersed surface of the body, a velocity potential is determined and subsequently hydrodynamic forces including the 2nd-order time-mean drift forces are calculated. The dynamic behavior of the body moored in irregular waves is investigated numerically by using central difference method. Hereby irregular wave trains are simulated with examining its repeatability by comparing the resulting spectrum with original one. Numerical results indicated that the body form obtained from the present analysis possesses in general a favorable hydrodynamic characteristics in comparison with a spherical buoy and that the maximum excursion of the body can be significantly reduced by setting pre-tension of an appropriate amount in the mooring cable.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.817-825
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• 2001

The natural frequencies of a flexible spinning disk misaligned with the axis of rotation are studied in an analytic manner. The effects of misalignment on the natural frequency need to be investigated, because the misalignment between the axis of symmetry and the axis of rotation cannot be avoided in the removable disks such as CD-R, CD-RW or DVD disks. Assuming that the in-plane displacements are in steady state and the out-of-plane displacement is in dynamic state, the equations of motion are derived for the misaligned spinning disk. After the exact solutions are obtained for the steady-state in-plane displacements, they are plugged into the equation for the dynamic-state out-of-plane motion. The resultant equation is a linear equation for the out-of-plane displacement, which is discretized by the Galerkin method. Based on the discretized equations, the effects of the misalignment are analyzed on the vibration characteristics of the spinning disk, i.e., the natural frequencies and the critical speed

• Physical Therapy Rehabilitation Science
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• v.3 no.1
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• pp.49-54
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• 2014

Objective: This study aimed to identify how various applications of weight bearing on the affected side of hemiplegia patients affect the ability of balance keeping of the affected leg and the gait parameters. Design: Cross-sectional study. Methods: Eighteen patients with hemiplegia participated in this study. There were twelve males and six females. This study investigated the effects of the single-leg stance exercise on dynamic balance, weight bearing, and gait ability compared with four conditions. Dynamic balance and weight bearing were measured using the step test (ST) of the affected side in stroke patients. In addition, gait parameters were measured using the optogait system for analysis of the spatial and temporal parameters of walking in stroke patients. Results: This study investigated the effect of the single leg stance exercise on the paralysis side. The ST showed significant findings for all conditions (p<0.05). Therefore, knee extension and flexion exercise on the affected side single-leg stance (condition 4) significantly improved dynamic balance and weight bearing on the affected side (p<0.05). In the condition of moving the knee joint in a single-leg stance was discovered that the stance phase time significantly increased more than in the condition of supporting the maximal voluntary weight on the affected side (p<0.05). Conclusions: Single-leg stance on the paralysis side with knee flexion and extension increased symmetry in weight bearing during stance phase time. This study suggests that single-leg stance exercises augments improved gait function through sufficient weight bearing in the stance phase of the affected side.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.46 no.2
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• pp.143-149
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• 2020

Objectives: Long-term facial paralysis results in degeneration of the distal nerve segment and atrophy of the supplied muscles. Options for these patients include free muscle transfer, temporalis myoplasty, and botulinum toxin injections for smile reanimation. In this study we aimed to evaluate the subjective and objective outcomes of these procedures. Materials and Methods: In our study, we retrospectively analyzed smile symmetry in patients with facial palsy (n=8) who underwent facial reanimation procedures. Results: Subjective analysis showed high satisfaction in seven out of eight patients. Objective analysis showed statistically significant improvement postoperatively in both vertical and horizontal smile symmetry at rest and during maximum smile (P<0.001). Conclusion: Choosing the ideal procedure for the patients is the most critical aspect for facial reanimation. Though free muscle transfer is considered gold standard procedure, temporalis myoplasty also gives satisfactory results. Residual synkinesis which can lead to disturbing aesthetic deformity can be effectively treated with botulinum toxin.

• Journal of Institute of Control, Robotics and Systems
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• v.2 no.2
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• pp.102-107
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• 1996

It is difficult to analyze the high speed rolling missile with the generally used missile body fixed coordinates. In this study, we formulate the dynamic equations of the high speed rolling missile with the principal axis of inertia, and make the analytical model of one axis steering missile using pitch/yaw symmetry and complex summation method. With this model we analyze the control characteristics and propose the design considerations of high speed rolling missile with one axis control fin using PNG law in conjuntion with a seeker signal.

• Korean Institute of Interior Design Journal
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• v.13 no.4
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• pp.21-28
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• 2004

This study was carried out to understand the characteristics of stairs in Palladio's villa. The subject of study are selected the twenty two villas with drawing in his book ‘The four books of Architecture’. Their cases are represented the characteristics of stair in architectural composition. Accordingly, it was analyzed and classified the architectural characteristics into space, form and plan at a villa. In conclusion, in aspect of spacial plan, staircases of Palladio's villa was presented more open and light in comparison with darked space of the medieval age. And it was intended to the connection or division between spaces of different character In an aspect of formal plan, dynamic form of stairs was divided into the two types. First, it was represented the effect of articulation in form. Second, stairs were represented the diagonal with the shape of itself. In an aspect of plan, his idea is coexisted with traditional thought and rational idea through the arrangement of symmetry md asymmetry. But at any rate, his concern was sought for the reasonable position. Also, he had represented the various characteristics in stairs such as his works in Renaissance period.

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.96-97
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• 2005

• Journal for History of Mathematics
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• v.33 no.4
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• pp.223-236
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• 2020

We examine how the formulas of the area and the circumference of a circle related to pi in the ancient Egyptian and the Old Babylonian fields of mathematics have been controversial. In particular, the Great Pyramid of Khufu, Ahmes Papyrus Problem 48 and Moscow Mathematical Papyrus Problem 10 have raised extensive controversy over π. We propose the pi-theory of the Great Pyramid of Khufu as a dynamic symmetry based on Euclid's rectangle. In addition, we argue that the ancient Egyptian or Old Babylonian mathematics influenced Solomon's Molten Sea, Plato and Archimedes' pi.

• Korean Institute of Interior Design Journal
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• no.41
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• pp.29-35
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• 2003

The purpose of this study is to analyze the architectural manifesto and design works characteristics of Walter Gropius. He was the director of Weimar Bauhaus that one of the advanced artificial movements in the early modern period. The almost of the early modern movements was related to the radical ideology and the manifesto. Especially Bauhaus originated from manifesto of artists teaching group with architect Walter Gropius. Therefore, the category of the study pitch upon Bauhaus architectural manifesto - Bauhaus Manifesto and Programme(1919) - and the representative works of Walter Gropius - Fagus Factory(1911-14), Dessau Bauhaus Building(1925-26), Siedlung Berlin-Siemensstadt(1929-30) and Harvard Graduate Center(1949). The conclusions of the study as per the above mentioned pill pose are the dynamic integration by non-symmetry in cubic form (formal characteristics) and organic continuity by reciprocality in transparent space (spatial characteristics).

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.427-429
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• 2002

In this paper, we investigated dynamic behaviors of liquid crystal director profiles by simulating two different modeling equations based on vectorial and tensorial approaches. By performing 3-dimensional simulation for a unit pixel, we found that the simulation results from the each of modeling equations lead to different motional behaviors of liquid crystal directors around the disclination line. This is due to the fact that the vectorial approach has a physically meaningless sign of liquid crystal director ${\overline{n}}$. Consequently, it is clarified that the tensorial approach gives more realistic behaviors for the rotation of the directors around the disclination line when the voltages were removed since it maintains nematic symmetry that gives an equivalence of ${\overline{n}}$ and its opposite - ${\overline{n}}$.