• Korean Journal of Applied Biomechanics
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• v.20 no.1
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• pp.109-116
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• 2010

This study aims to comparatively analyze kinetic variables that affect high jump records and thus to provide the basic data for enhancement of physical education teachers' teaching skills and expertise. 10 students who were majoring in physical education in a college of education - five males and five females - were chosen for the experiment in which the 3D image analyzer and ground reaction force measuring unit were adopted. The kinetic variables of the groups, the characteristics and differences were analyzed, and the correlation between each variable and record in each group was examined. The results are as follows: As to the height of center of gravity from one step before stamping to landing, the vertical velocity of the center of gravity at take off, the vertical velocity of the limbs at take off, the angles of the hip joint and ankle joint of the jumping leg, it turned out that male were better than female. As to the angles of the hip joint and ankle joint of the lead leg, female recorded higher values than male. As to the maximum vertical ground reaction force, the maximum horizontal ground reaction force, the vertical impulse, it turned out that male were better than female.

• Structural Engineering and Mechanics
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• v.34 no.4
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• pp.399-416
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• 2010

The purpose of this paper is to utilize the numerical assembly method (NAM) to determine the exact natural frequencies and mode shapes of a multi-step beam carrying multiple rigid bars, with each of the rigid bars possessing its own mass and rotary inertia, fixed to the beam at one point and supported by a translational spring and/or a rotational spring at another point. Where the fixed point of each rigid bar with the beam does not coincide with the center of gravity the rigid bar or the supporting point of the springs. The effects of the distance between the "fixed point" of each rigid bar and its center of gravity (i.e., eccentricity), and the distance between the "fixed point" and each linear spring (i.e., offset) are studied. For a beam carrying multiple various concentrated elements, the magnitude of each lumped mass and stiffness of each linear spring are the well-known key parameters affecting the free vibration characteristics of the (loaded) beam in the existing literature, however, the numerical results of this paper reveal that the eccentricity of each rigid bar and the offset of each linear spring are also the predominant parameters.

• Journal of Korea Game Society
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• v.20 no.1
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• pp.13-22
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• 2020

This study is about the VR controller that can provide an enhanced experience in VR by augmenting the sense of weight. In this study, the method of changing the center of gravity of the controller was used as a means of transmitting the sense of weight. The experiment was carried out with a device that could change the center of gravity to find the minimum distance at which people can perceive the difference in weight. The results showed that the weight difference between the two stimuli can be perceived at a distance of about 5 cm regardless of the position of the starting stimulus.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.9
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• pp.942-949
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• 2014

In this paper, a new steering system for a self-balancing electric scooter is proposed with an intuitive steering command input method, where the steering command is generated from the rider's motion of shifting body to move the center of gravity toward the rotational direction. For the purpose, weight distributions on the rider's feet are measured using force sensors placed beneath the rider's feet, and the difference is applied to a steering control system. Stability of the steering system and resultant radius of gyration is investigated by modeling the steering system in consideration of the rider's motion and centrifugal force. The proposed steering system is applied to experiments, and the results are presented to prove the validity of the proposed method.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.4
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• pp.149-155
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• 2016

This paper presents a control method of a mecanum wheel-based omni-directional electric board using driver weight shift. Instead of a steering device such as a joystick or a remote controller, 3 degree-of-freedom driving command for translational and rotational motion of the omni-directional electric board is generated from position of center of gravity measured from weight distribution. The weight shifting motion is not only a driving command but also an intuitive motion to overcome inertial forces. The overall control structure is presented with experimental results to prove validity of the proposed method.

• Journal of the Ergonomics Society of Korea
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• v.5 no.1
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• pp.3-9
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• 1986

This research is aimed at examining age-related changes of postural sway when people stand upright, examining external effects which can be exerted upon the postural sway (experiment 1), and also analyzing specific changing characters of posture-control by sudden impacts (experiment 2). The total number of subjects was 115, who are in twenties through seventies and 75 of them were participated in experiment 2. In experimen 1, the subjects were examined for 25 seconds respectively while standing upright with both feet and with eyes opened, standing upright with both feet and with eyes closed, and standing upright with a single foot and with eyes opened. In experiment 2, only while standing upright with both feet and with eyes opened they were examined for 5 seconds. Main findings were as follows: 1. In the single-foot standing position, the growing older exerted more important effects upon the fluctuation length and area of the center of gravity than in the both-foot standing position. 2. The standard deviation was increasing with age in the fluctuation length and the fluctuation area of the center of gravity. 3. There were no significant differences in daily variation, temperature change, and muscle burdening. 4. The recuperation from the postural sway by external impacts was so slow with age. 5. There were little differences in decrease frequencies among the subjects but younger persons.

• Korean Journal of Applied Biomechanics
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• v.20 no.3
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• pp.311-318
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• 2010

This study examined the double piked dismount among the landing techniques of parallel bars based on three-dimensional motion analysis. Four male national gymnasts were the subjects. This study was performed to provide quantitative data highlighting players strengths and weaknesses to enable more stable landing technique. The variables analyzed were the position and velocity of center of gravity(CG) and angles of shoulder joints, hip joints, and trunk. The results are as follows: S1 secured the height of flight with fast vertical rise. After the easy spin in the air, he conducted a stable landing maintaining a proper hip joints angle. S2, S3, and S4, however, began the backward somersault already before leaving the bars, so they moved backward greatly making it more difficult to achieve a higher flight path. As a result, they couldn't control the velocity of their backward movement at landing. For a stable landing, they have to maintain the negative shoulder angle when rising, minimize both antero-posterioror side-to-side movements by doing a strong tap using hip joints, to secure the height of flight before the somersault. Results also show that at the descent, they should conduct rapid spinning by increasing their shoulder and hip joints to the maximum while controlling their velocity.

• 한국HCI학회:학술대회논문집
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• 2006.02b
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• pp.356-361
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• 2006

모션캡처기술은 이미 많은 애니메이션과 게임에서 보편화되어 사용되고 있다. 하지만, 이런 좋은 기술을 뒤로 한 채 아직도 많은 애니메이터들이 직접 애니메이션을 하고 있다. 모션캡처 기술비용과 제작시간 때문이기도 하지만 사람과 상이한 체형을 가진 3D 캐릭터에 사람의 모션을 적용하기엔 어색한 부분이 많기 때문이다. 또한, 캐릭터의 특징을 부각시키거나 왜곡시키는 등의 과장의 표현은 불가능하다. 캐릭터의 생명은 그 캐릭터가 가진 성격과 체형에서, 그 캐릭터만의 자연스런 움직임을 표현하는데 있다. 기획과 의도에 따른 특성들을 과장하여 표현하되 인간의 동작에 익숙해 있는 우리 눈에 어색함으로 비춰지지 않도록 해주어야 비로소 생명력이 있는 캐릭터를 만들 수 있다. 다양한 모양의 캐릭터는 서로 다른 무게중심을 가졌고 이를 고려하지 않고 애니메이션 했을 때 여러 가지 문제점이 생긴다. 이러한 문제점은 캐릭터가 자연스럽지 못하게 보이는 가장 큰 원인 중 하나다. 본 논문은 게임과 애니메이션 등에서의 3D 캐릭터가 더욱 생생하고 현실적으로 보이도록 돕는데 그 목적이 있다. 그 중, 중요한 요소인 무게중심에 대한 이해와 함께 활용방법에 대한 연구에 목적을 둔다. 캐릭터의 자연스러운 움직임을 위해 무게중심은 반드시 고려해야 할 문제이고 캐릭터의 특성 및 성격 표현에도 중요한 영향을 미친다. 애니메이터들에게 무게중심에 대한 중요성을 알리고 새로운 접근방법을 제시하는 것을 본 논문의 가치로 삼는다.

• The KSFM Journal of Fluid Machinery
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• v.15 no.1
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• pp.46-51
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• 2012

This study is to confirm the deformation of blade when the location of stacking is moving. Also, it desire to determine the most stable location of stacking from the analysis. In the previous study, it is Known that moving the location of stacking is not influence to the aerodynamic performance. In this study SolidWorks premium 2010 SP4 is used for structure analysis. In reference blade and other 3 model analysis, the two mesh type is used, one is standard mesh type in SolidWorks, the other is curvature-based mesh type. The result of curvature-based mesh type is more stable than one of the standard mesh type regardless of mesh size, the number of mesh. The deformation of blade tip is the smallest, when the location of stacking is identical to the center of gravity of the blade section profile. So, if possible is design, this study recommends that the location of stacking is identical to the center of gravity the blade.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.7
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• pp.661-666
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• 2015

This paper presents control performance improvement by modifying center of gravity (COG) of an underwater robotic platform. To reduce the oscillation or to increase the positioning accuracy, it is important to accurately know the COG of an underwater robotic platform. The COG is determined by the three measured tilting angles of the platform in different postures. The tilting angle is measured while the platform is hanged by two strings. Using coordinate transformation, the plane of intersection is defined from the angle of the platform and the position of the string. The COG of the robotic platform is directly calculated by the intersected point in three defined planes. The measured COG is implemented to the control algorithm that is pre-designed in the previous research, and the empirical result on tilting gives 48.26% improved oscillation performance comparing to the oscillation result with the ideal COG position.