• 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.

• Journal of the Korean Applied Science and Technology
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• v.38 no.1
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• pp.1-8
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• 2021

The purpose of this study was to analyze relationship between biomechancal factors and diver's distance during golf driver swing. Fifteen professional golfers were participated in as subject. Eight motion capture cameras(250 Hz), 2 force plates(1000 Hz), and Trackman were used to collect kinematic and kinetic datas. It was performed Pearson's correlation analysis using SPSS 24.0. The level of significance was at .05. Ball speed, club head speed, X-Factor, and ground reaction force were correlated on driving distance, However, smash factor and knee moment were not correlated on driving distnace. Ball speed, club head speed, X-Factor, and ground reaction force were effected to driving distance, but smash factor and knee moment were not effected to driving distance.

• The Journal of the Korea Contents Association
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• v.13 no.10
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• pp.523-532
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• 2013

When the golf club hits the ground prior to making contact with the golf ball, we define it as 'fat shot'. The aim of this research was to investigate the difference between normal shot and fat shot in golf. Five candidates playing as recreational golfer participated in this research and they were all right-handed people. Time phase between each event, wrist cocking angle, elbow extension-flexion angle, backswing height, pelvis angle, thorax angle, L-GRF, R-GRF, pelvis linear velocity, pelvis angular velocity and COG path were calculated. For statistical analysis the paired T-test was used. An early un-cocking, an early right elbow extension and impact with leaving their weight behind foot were not reasons of fat shot. Backswing height, X-Factor, pelvis angle and thorax rotation angle were not different between normal shot and fat shot. But we could find a pattern of abrupt pelvic movement and weight shift to target direction just before impact in case of fat shot. In addition fat shot showed time-delayed and small value of pelvis linear velocity pattern to upward during downswing phase as against normal shot.

• 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.

• Asian Journal of Turfgrass Science
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• v.23 no.1
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• pp.61-76
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• 2009

The purpose of this study are to investigate the reasonable maintenance expense of golf course according to the size and management system of each golf course. The maintenance cost per hole per golfer of 29 golf courses and the maintenance cost for items and locations of 8 golf courses were analyzed. 1. As golfers per hole increased, maintenance cost per hole per golfer decreased. 2. The decisive cost factors for maintenance cost of golf course are the number of annual golfers, the total course size, the management system, and automation of course facilities. 3. Maintenance cost of golf courses contained the landscaping areas except for building and parking lots is $869^{\}/_{m^2}$ Korean won. 4. Average maintenance cost of 8 golf courses is $44,325,000^{\}/_{hole}$. 5. Labor cost marked the largest portion in the total cost. Among the items of labor cost, repair cost for green ball mark was the highest with the ratio of 26%(\4,163,000). 6. Material cost for Fairways which reaches 30% of the total area was composed of $22%{\sim}44%$ of the total cost of materials. Cost of imported fertilizers, pestcides for insects and diseases, and sands for top dressing was the highest. 7. Material cost for Green which reaches 2% of the total area was composed of $28%{\sim}36%$ of the total cost. Cost of imported products such as particle-shaped fertilizers, micro mineral fertilizers, and soil conditioners was the highest. 8. There is no difference in cost between chemical fertilizers and the environmentally friendly fertilizers even if environmentally friendly fertilizers using microorganism or chitosan materials are also expensive.

• Journal of Sport and Applied Science
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• v.7 no.1
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• pp.11-20
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• 2023

Purpose: This study sought to examine the symbolization of brand identity in Nike golf advertisements and to provide implications for sporting goods ads. Research design, data, and methodology: The study employed Socher's semiotic theory to analyze characteristics embedded in Nike video advertisements. In specific, the study selected 'No cup is safe' among Nike video ads and analyzed structures of ad message and presented metaphors of ad messages. Results: As a study on the semiotic analysis of communication by case, this study investigated how the brand identity pursued by Nike in the advertisement is symbolized by identifying the signifier and signified in the advertisement. As a result of the study, it was possible to segment and analyze a total of 8 advertisement scenes, from the most important tee shot in golf, setting the aiming, sending to the center of the fairway, and applying the general situation of ball in and hole out to the cases of Tiger Woods and McIlroy, thereby helping the general public. Conclusions: Summary of above results showed that it was also conveying the message of metaphor and metonymy that 'I can be like Tiger Woods and McIlroy' by using Nike golf products. Further implications were discussed.

• Proceedings of the Korean Society of Computer Information Conference
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• 2016.07a
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• pp.199-200
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• 2016

스포츠 산업 응용 분야에서 공의 실시간 품질검사는 산업 생산성과 경쟁력 견지에서 중요한 이슈이다. 컴퓨터 비전 기반 자동 품질검사는 이 문제를 해결하는 하나의 방법이다. 머신 비전 시스템은 품질관리 및 산업프로세스의 실시간 피드백을 주어, 물리적인 제한과 사람의 주관적인 판단을 극복할 수 있다. 컴퓨터비전 기반 시스템에서 디지털카메라에서 취득되는 디지털이미지는 주로 24-비트 컬러이미지이다. 이처럼 많은 레벨을 가지는 이미지분석은 복잡한 이미지 처리기법을 필요로 한다. 그러나 실시간 애플리케이션에서, 한 부분은 실시간으로 검사되어져야 한다. 이 논문에서는 최적의 임계값을 사용하여 스포츠산업계의 산업요구 사항을 만족하는 골프공 품질검사 시스템을 개발하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.123-125
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• 2013

우리는 흔히 골프 클럽의 휘둘러 골프공이 맞아 나가는 것을 보게 된다. 본 논문에서는 골프채 헤드가 골프공을 일정속도로 움직여 치고 난 후 골프채의 헤드는 같은 방향으로 일정 속도로 움직일 때 골프공을 치고 날아가는 골프공의 속도를 구한다. 골프공을 치기 전의 속도가 각각 다를 경우의 골프공의 속도를 각각 구한다. 골프를 칠 때 헤드의 속도, 골프공의 질량, 임팩트, 임팩트 후의 날아가는 속도, 그리고 임팩트 후의 이동 방향 등을 쉽게 알아보도록 하는 것이 본 논문의 목적이다.

• Korean Journal of Applied Biomechanics
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• v.25 no.1
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• pp.11-19
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• 2015

Objective : The purpose of this study was to analyze the correlation between physical factors (X-factor, X-factor stretch) and club factors (club speed, ball speed, club path, smash factor, vertical launch angle, spin rate, flight time, total length) during impact and it affect on the total distance of the ball during a golf driver swing. Background : There were not enough studies that analyzed the correlation between physical factors(X-factor, X-factor stretch) and club factors(club speed, ball speed, club path, smash factor, launch angle, spin rate, flight time, total length) during a purpose swing to increase total distance. Method : For this study, 9 right handed professional male golfers (KPGA) were chosen. The test subject group used their own drivers and each took a total of 10 swings. These swings consisted of 5 purpose swings to increase total distance and 5 normal swings. Results : The purpose swing to increase total distance showed larger physical factors(X-factor, X-factor stretch) compared to a normal swing however the results were not statistically significant. Total distance increased during a purpose swing as a result of ball and club speed. Conclusion : The results showed that club factors, ball speed and club speed contributed the most in affecting the total distance of the ball during a purpose swing.

• Korean Journal of Applied Biomechanics
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• v.27 no.4
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• pp.269-278
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• 2017

Objective: The purpose of this study was to develop a goal setting method for increasing the probability of a holed in a side inclined putting stroke. Method: Three-dimensional video data was recorded at a frequency of 120 hz per second after synchronizing 19 infrared motion capture systems (Qualisys, Gothenburg, Sweden). Putting green used a polycarbonate plate ($1.2{\times}2.4{\times}0.01meter$) with coefficient of friction (${\mu}=0.062$) and a real curve of the actual hole. Results: The velocity ratio between the club and the ball was 1:1.6 under various ball speed conditions in this study. The overall position of the break is 1 m to 1.4 m from the point where the ball leaves. If there is a slope, the ball follows the target line by the straightening force, and when it reaches 1 m position, the straightening force decreases by 30~50% and reaches to the deviation (break) point which is severely influenced by the slope. From here, the ball is aimed in a direction other than the target, and the size is affected by the slope. Conclusion: If there is a side slope, the ball moves away from the straight line, and the larger the slope, the closer the break point is to the starting point of the ball. Therefore, it is necessary to calculate the degree of departure according to the slope carefully, and it is preferable that the slower the speed is, the more the influence of the slope becomes. It is preferable to use the center of the hole as a reference when calculating the departure.