• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.05a
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• pp.167-171
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• 2004

The Spar platform with deep draft is characterized as effective structure in extreme wave condition, which has larger natural period than that of waves in sea. In this paper, the time simulation of motion responses of Spar with catenary mooring line is presented in irregular waves. The memory effect is modeled by added mass at infinite frequency and convolution integrals in terms of wave damping coefficients. The added mass, wave damping coefficients and wave exciting forces are obtained from three-dimensional panel method in the frequency domain. The motion equations are consisted of forces for inetia, memory effect, hydrostatic restoring, wave exciting and mooring line. The forces of mooring line are modeled as quasi-static catenary cable.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.5
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• pp.1-7
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• 2004

The Spar platform with deep draft is characterized as effective structure in extreme wave condition, which has larger natural period than that of waves in sea. In this paper, the time domain simulation of motion responses of Spar with catenary mooring line is presented in irregular waves. The memory effect is modeled by added mass at infinite frequency and convolution integrals in terms of wave damping coefficients. The added mass, wave damping coefficients and wave exciting forces are obtained from three-dimensional panel method in the frequency domain. The motion equations are consisted of forces for inertia, memory effect, hydrostatic restoring, wave exciting and mooring line. The forces of mooring line are modeled as quasi-static catenary cable.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.2
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• pp.110-116
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• 2005

This paper deals with interaction between two bubbles or particles and flow around them, visualized by a moving object flow image analyzer(MOFIA) consisting of a three-dimensional (3D) moving object image analyzer(MOIA) and two-dimensional particle image velocimetry(PIV). The experiments were carried out for rising bubbles or particles of various densities, sizes, and/or shapes in stagnant water in a vertical pipe. In the MOFIA employed, 3D-MOIA was used to measure particles or bubbles motion and PIV was used to measure fluid flow, The experimental results showed that the interaction was characterized by the shape, size and density of two particles or bubbles.

• Korean Journal of Applied Biomechanics
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• v.14 no.1
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• pp.99-115
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• 2004

In order to Know the correct swing methods in golf swing it is important to understand the whole swing path but also the concept of swing plane. But, most amateur golfers don't Know the concept of swing plane well. Therefore this study was trying to make a good material that makes the concept of swing plane easy to understand. A good swing motion data was obtained from a professional golfer using the three-dimensional DLT method. This swing motion was divided into 10 phases and evaluated using the concept of swing plane. The result of the analyze show a good matches between the path of the club and swing plane. This result was summarized as a 3 dimensional graphics to provide a good material to teach the golf swing well.

• Computers and Concrete
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• v.23 no.5
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• pp.303-309
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• 2019

This study investigates axisymmetric fractional vibration of an isotropic hyperelastic semi-linear thin disc with a view to examine effects of finite deformation associated with the material of the disc and effects of fractional vibration associated with the motion of the disc. The generalized three-dimensional equation of motion is reduced to an equivalent time fraction one-dimensional vibration equation. Using the method of variable separable, the resulting equation is further decomposed into second-order ordinary differential equation in spatial variable and fractional differential equation in temporal variable. The obtained solution of the fractional vibration problem under consideration is described by product of one-parameter Mittag-Leffler and Bessel functions in temporal and spatial variables respectively. The obtained solution reduces to the solution of the free vibration problem in literature. Finally, and amongst other things, the Cauchy's stress distribution in thin disc under finite deformation exhibits nonlinearity with respect to the displacement fields whereas in infinitesimal deformation hypothesis, these stresses exhibit linear relation with the displacement field.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1149-1150
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.167-168
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• 2010

• 순환기질환의공학회:학술대회논문집
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• 2003.11a
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• pp.8-9
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• 2003

• Korean Journal of Applied Biomechanics
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• v.15 no.3
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• pp.161-173
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• 2005

Recently among several tennis techniques forehand stroke has been greatly changed in the aspect of spin, grip and stance. The most fundamental factor among the three factors is the stance which consists of open, square and closed stance. The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle according to open stance patterns during forehand stroke in tennis. For the movement analysis three dimensional cinematographical method(APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVlEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and racket head angle were defined 1. In three dimensional maximum linear velocity of racket head the X axis showed $11.41{\pm}5.27m/s$ at impact, not the Y axis(horizontal direction) and the z axis(vertical direction) maximum linear velocity of racket head did not show at impact but after impact this will resulted influence upon hitting ball It could be suggest that Y axis velocity of racket head influence on ball direction and z axis velocity influence on ball spin after impact. the stance distance between right foot and left foot was mean $74.2{\pm}11.2m$. 2. The three dimensional anatomical angular displacement of shoulder joint showed most important role in forehand stroke. and is followed by wrist joints, in addition the movement of elbow joints showed least to the stroke. The three dimensional anatomical angular displacement of racket increased flexion/abduction angle until the impact. after impact, The angular displacement of racket changed motion direction as extension/adduction. 3. The three dimensional anatomical angular displacement of trunk in flexion-extension showed extension all around the forehand stroke. The angular displacement of trunk in adduction-abduction showed abduction at the backswing top and adduction around impact. while there is no significant internal-external rotation 4. The three dimensional anatomical angular displacement of hip joint and knee joint increased extension angle after minimum of knee joint angle in the forehand stroke, The three dimensional anatomical angular displacement of ankle joint showed plantar flexion, internal rotation and eversion in forehand stroke. it could be suggest that the plantar pressure of open stance during forehand stroke would be distributed more largely to the fore foot. and lateral side.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.643-644
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• 2006

The purpose of this study is to experimentally analyze swing motion with soft golf clubs and compare with that with normal golf clubs. Soft golf is newly devised recreational sport based on golf but focus on the playability for the elderly. The subject fur the experiment performed swing motion using a normal golf club and a soft golf club in turn. The swing motion of the subjects was tracked using an opto-electric three-dimensional motion analysis system. The results were compared against those obtained with a normal golf club. The range of motion was analyzed along with top head speed for two cases. It was found that higher club head speed could be achieved with reduced range of motion at lumbar joint using soft golf club when compared against the swing using regular club. The lower range of motion fur lumbar bending means reduced risk of injury at the joint. So, it is projected that we can reduce the risk of injury with soft golf while maintaining the club head speed.