• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.117-131
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• 2003

This study simulated the range of golf ball with different projection angles using a drive swing condition. For the simulation purpose, the differential equation of dynamics was induced by using Bernoulli's principle and average back spin frequency, instant velocity, and dimple of golf ball from amateur group, professional group, and Tiger Woods were chosen as the initial condition. The study result indicated that lift coefficient($C_{lift}$) relative to drag coefficient ($C_d$), 0.3 of differential equation was applied differently in terms of back spin Sequency, and when $C_{lift}$ was 0.4 for amateur, 0.5 for professional, and 0.7 for Tiger Woods the projection ranges of ball were closely matched with initial condition. With selected $C_{lift}$ and back spin frequency of initial condition, the ranges with different projection angle was measured as 193m ($13-17^{\circ}$) for amateur, 240m ($9-13^{\circ}$), professional and 273m ($9^{\circ}$)Tiger Woods, respectively. For the range in terms of back spin frequency and projection angle, the amateur group indicated relatively high spin frequency (70 RPS) and showed the maximal range (195m) with $13^{\circ}$ of projection angle. The tendency of longer range with higher projection angle was also found under the different conditions of spin frequency in this group. The professional group showed their maximal range (245m) with conditions of 60RPS of spin frequency and $9^{\circ}$ of projection angle. Their range was decreased dramatically when the spin frequency was reduced to 40-50 RPS. For Tiger Woods, the maximal range was found with 40RPS of spin frequency and the range was decreased notably when the spin frequency was above 40RPS.

• Science of Emotion and Sensibility
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• v.6 no.2
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• pp.59-64
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• 2003

The national standard anthropometry of Korea is conducted every 5∼6 year term after its first research was started in 1979, The fourth research was conducted in 1997. The result of the national standard anthropometry has been reflected in manufactured goods design of allied industries such as clothing, shoes and furniture. In this paper, we measured anthropometry data for every bodily figurative classification after dividing users according to gender, age and bodily figure using the result of the national standard anthropometry. We constructed 3D character through the process of analyzing interrelation of measured anthropomeoy and measuring representative category. In the process for organization , we measured anthropometry which can effectively express sports action of golf, tennis etc. We made it by presenting measurement which is able to form each type of 3D character after the category was decided. Quantitative and objective valuation for posture and action became possible by developing visible information offer and posture action analysis protocol in theoretical approach for analysis of posture and action in sports.

• Korean Journal of Applied Biomechanics
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• v.19 no.4
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• pp.729-738
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• 2009

The purpose of this study was to analyze the impact accuracy and kinematic parameters of skill level and eye-tracking type during putting strokes. For comparison, five elite golfers and five novice golfers participated in this study. Three-dimensional kinematic data were collected for each subject while 10 putting trials were performed for each skill level and eye-tracking type. The APAS system was used to compute the impact accuracy and kinematic parameters of putter heads. The putting stroke was divided into three phases: back swing, downswing, and follow-through. The findings indicated that significant differences were found in skill level as it affected the rate of success. For impact accuracy and the displacement of putter heads, a significant difference was found for the skill level, particularly in backs-wing and follow-through. In addition, the displacement of the putter head had a greater influence on stroke accuracy than on velocity.

• Korean Journal of Applied Biomechanics
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• v.17 no.2
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• pp.217-226
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• 2007

Putting score counts about 43 % of the golf score. The dominant idea of the putting motion to amateur golfers as well as to many professional golfers is a pendulum-like motion. If a golfer's putting stroke motion is a pendulum-like motion, the putting motion should be straight-back-and-through, the same backswing, downswing, and follow through length and period, and a swing with a fixed hinge joint. If the putting motions of the human are different from the pendulum motion, there could be confusion in understanding and teaching golf putting. The purpose of this study was to examine the center of rotation(COR) of the putter head to reveal whether professional golfers really putt like a pendulum. Thirteen male professional golfers were recruited for the study. Each golfers executed 10.94 m putts six times on an artificial grass mat. Putter head position data were collected through a 60 Hz three-dimensional motion analysis system and low pass filtered with cut-off frequency of 6 Hz. COR of the putter head was mathematically acquired. Each golfer's last five putting motions were considered. The results show that the COR of the putter head was neither fixed nor located inside of the golfer. The medio-lateral directional component of the COR of the putter head fluctuated in the range of 10 cm during downswing and follow through. The anterior-posterior directional component of the COR of the putter head was fixed from the beginning of the downswing through impact. Just after impact, however, it moved to the target up to 60 cm. The superior-inferior directional component of COR of the putter head moved in a superior direction with the beginning of the downswing and showed peak height just prior to impact. During the follow through, it moved back in an inferior direction. The height-normalized peak value of the COR of the putter head was $1.4{\pm}0.3$ height. Technically speaking, male professional golfers' 10.94 m putting motion is not a pendulum-like motion. The dominating idea of a pendulum-like motion in putting might come from the image of the flawless, smooth motion of a pendulum.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.37-44
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• 2007

This study compared the Character Studio of 3ds Max and OpenGL to find an adequate modeling method of character animation to be used in motion analysis in the area of motor mechanics. The subject was one male golfer. We obtained the positional coordinates of marks needed by photographing the subject's golf swing motions. Because the method based on the Character Studio used meticulously designed character meshes, it enabled high.level animation but it took a long time in applying physique and demanded the repeated adjustment of each motion data. With the method based on OpenGL, a character completed once could be usable to almost every testee and desired program control was available, but because each character had to be created by making a computer program, it was hard to make characters delicately. Because the method using the Character Studio is actively studied not only in motor mechanics but also in many research areas, it is expected to be more usable in the near future. On the contrary, the method based on OpenGL is easily applicable and allows the convenient use of other mechanical data.

• Journal of IKEEE
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• v.24 no.4
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• pp.1109-1116
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• 2020

The matching score evaluating human copying ability can be a good measure to check children's developmental stages, or sports movements like golf swing and dance, etc. It also can be used as HCI for AR, VR applications. This paper presents a method to evaluate the motion similarity between demonstrator who initiates movement and participant who follows the demonstrator action. We present a quantification method of the similarity which utilizes Euclidean L2 distance of Openpose keypoins vector similarity. The proposed method adapts DTW, thus can flexibly cope with the time delayed motions.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.787-790
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• 2021

본 논문에서는 최신 모션 인식 기술을 활용하여 골프 스윙 비디오에서 사람의 자세를 추정한 후 다양한 원인으로 오검출된 좌표들을 보정하여 자세 추정의 정확도를 높이는 방법을 제안한다. 기존의 사람 자세 추정 모델은 골프 스윙 데이터에서 오검출, 반전, 불안정성, 미검출의 문제를 보여 정확한 자세 추정을 어렵게 했다. 이를 해결하기 위하여 본 연구에서는 자세 추정시 발생하는 이상치 데이터들을 Bi-LSTM 으로 학습하고 골프 스윙의 특징을 고려한 간단한 규칙을 통하여 이상치 데이터를 효과적으로 검출하고 이를 보정하는 방법을 제안한다. 또한 다양한 실험과 분석을 통하여 제안하는 방법이 골프 스윙 모션에서 사람의 자세를 정확히 추정할 수 있음을 보인다.

• Journal of the Korean Applied Science and Technology
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• v.35 no.1
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• pp.273-283
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• 2018

The purpose of this study is to analyze the optimum driver selection according to shaft intensity, shaft length and shaft weight that are determining factors of driver shot. To achieve the above purpose, the subject were participate with handicap zero 10 male pro golfer and mean score 90(handicap about 18) amateur 10 male golfer. The used club limited number 1 driver, we tested 24 driver which is shaft intensity, length, weight, total weight and swing weight. Dependent variable was strike ball speed, flying distance and head speed. The findings can be summarized as follows. First, There is a significantly difference in CPM. Ball speed, head speed and flying distance according to driver shaft intensity were found to be the best when CPM is 230<. Second, There is a significantly difference in shaft length. Ball speed, and head speed according to driver shaft length were found to be the best at 46 inch and flying distance were found to be the best at 45 inch. Third, There is not significantly difference in SW. Ball speed and flying distance according to driver shaft weight were found to be the best with 65g. In the case of head speed, it was the fastest with 50g shaft. Four, total variables were significantly difference between in pro and amateur golfer. In conclusion, there would be differences in individual physical condition but the best result was found with a driver of CPM 230<, shaft length 46inch, and shaft weight 65g.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.10
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• pp.419-426
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• 2022

In this paper, we propose a method to improve the accuracy of 3D human pose estimation model in various move motions. Existing human pose estimation models have some problems of jitter, inversion, swap, miss that cause miss coordinates when estimating human poses. These problems cause low accuracy of pose estimation models to detect exact coordinates of human poses. We propose a method that consists of detection and correction methods to handle with these problems. Deep learning-based outlier detection method detects outlier of human pose coordinates in move motion effectively and rule-based correction method corrects the outlier according to a simple rule. We have shown that the proposed method is effective in various motions with the experiments using 2D golf swing motion data and have shown the possibility of expansion from 2D to 3D coordinates.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.197-206
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• 2002

The purpose of this study was to investigate the putter head movement during the putting strokes. Highly skilled 5 golfers(less than 3 handicaps) and 5 novice golfers(having no golf experience) participated in this study. A target distance was 3 m. Movements of the putter head were recorded at 60 Hz with two video cameras. The results showed that the novice golfers moved the club significantly longer than the expert golfers(p<.0001). Accoring to a movement time, novice golfers moved their club significantly faster than the expert golfers(p<0.001). Novice golfers could not control the club head effectively, and could not hit the ball correctly. Based on the impact zone movement, sweet spot of novice golfers moved faster(along the line of putt), higher(along the vertical line), and wider(along the side to side line) than that of expert golfers.