• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.361-380
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• 2002

The purposes of this study were to a analysis of friction relation between tennis outsole and tennis playing surfaces. Tennis footwear is an important component of tennis game equipment. It can support or damage players performance and comfort. Most importantly athletic shoes protect the foot preventing abrasions and injuries. Footwear stability in court sports like tennis is incredibly important since it is estimated that as many as 45% of all lower extremity injuries occur in the foot and ankle. The friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. The friction force opposes the motion of the object. Friction results when two surfaces are pressed together closely, causing attractive intermolecular forces between the molecules of the two different surfaces. The outsole provides traction and reduces wear on the midsole. Today's outsoles address sport specific movements (running versus pivoting) and playing surface types. Different areas of the outsole are designed for the distinct frictional needs of specific movements. Traction created by the friction between the outsole and the surface allows the shoe to grip the surface. As surfaces, conditions and player motion change, traction may need to vary. An athletic shoe needs to grip well when running but not when pivoting. Laboratory tests have demonstrated force reductions compared to impact on concrete. There is a correlation between pain, injury and surface hardness. These are a variety of traction patterns on the soles of athletic shoes. Traction like any other shoe characteristic must be commensurate and balanced with the sport. The equal and opposite force does not necessarily travel back up your leg. The surface itself absorbs a portion of the force converting it to other forms of energy. Subsequently, tennis court surfaces are rated not only for pace but also for the percentage of force reduction.

• The Journal of the Korea Contents Association
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• v.20 no.3
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• pp.424-431
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• 2020

This paper focused on the development of sports robot that detects a human player and shots a serve ball automatically. When robot technologies apply to the sports machine, the domain problems occurs such as outdoor environments and playing condition to recognize the visual and the vocal modalities. Gaussian mixture model and Kalman filter are used to detect the player's position in the left, right, and depth direction and to avoid the noises caused by the player's posture variation around the net. The sports robot is designed by the pan-tilt structure to shot a serve ball by pneumatic control under the multi layered software architecture. Finally, the proposed tracking and the machine performance are discussed by experimental results.

• Korean Journal of Applied Biomechanics
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• v.21 no.4
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• pp.421-427
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• 2011

The purpose of this study was to analyze the difference between male and female tennis players' two-handed backhand stroke and to provide basic data which helps precise and efficient instruction for the sake of precise postures, enhanced performances and skills. 5 male and 5 female university players were recruited as subjects, and the mean difference between the kinematic variables such as the time from backswing to impact and total swing time, racket head velocity, change of the center of body gravity in two-handed backhand stroke through three-dimensional motion analysis. The test data was analyzed by t-test, and the alpha level of ${\alpha}$=.05 was set for all tests of significance. The findings of the study were as follows; First, there was no difference in the time from backswing to impact and total time of

• Journal of Korea Game Society
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• v.5 no.3
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• pp.3-10
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• 2005

We present the computer table tennis game using player's swing motion. We need to transform a real world coordinate into a virtual world coordinate in order to hit the virtual ball. We can not get a correct 3-dimension position of racket in environment that using one camera or simple image processing. Therefore we use Augmented Reality (AR) concept to develop the game. This paper shows the AR table tennis game using gesture and method to develop the 3D interaction game that only using one camera without any motion detection device or stereo cameras. Also, we use a scan line method to recognize gesture for speedy processing. The game is developed using ARtoolkit and DirectX that is popular tool of SDK for game development.

• Journal of the Korean Applied Science and Technology
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• v.37 no.5
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• pp.1314-1322
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• 2020

Sports drinks help optimize and improve performance by delaying and eliminating the buildup of fatigue-causing substances in the body during exercise. Saengmaeg-san is a nature-friendly traditional beverage that has no side effects on the human body and can quench thirst. However, studies on the relationship between exercise ability and Saengmaeg-san are insufficient. The purpose of this study was to prescribe Saengmaeg-san during the summer training period of 4 weeks and to analyze the effect on body composition and exercise performance. Seventeen male participants were divided into 3 groups (Saengmaeg-san acid intake group [n=9], placebo group [n=8]), and body composition (height, weight, muscle mass, fat mass, BMI) and conducted exercise performance (total exercise time and HRmax). In our study, Saengmaeg-san intake had a positive effect on exercise performance, such as decreased body fat percentage, increased exercise time, and decreased HRmax. Therefore, Saengmaeg-san showed the potential as a sports drink. In the future, additional studies on fatigue-related substances, immune function-markers, and blood lipids are needed in order to clearly explain the change in exercise performance due to consumption of Saengmaeg-san.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.7
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• pp.3638-3653
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• 2019

Designing a user interface is important because the user interface determines the level of physical and mental engagement of the user resulting in their level of learning. This paper investigated how physical engagement through a different user interfaces is associated with fun and learning and presented a theoretical physical engagement model called, PEM, developed based on an empirical user study. The PEM model describes how a game user interface is associated with the level of fun and learning, particularly in playing a full body engaged game. There are many different types of games but the Wii Tennis, an embodied interactive game, was chosen as an instance of full body engaged game. A user study with 32 participant's age ranged from 21 to 40 years old revealed that there is a positive correlation between both fun and learning and the level of physical engagement through two different user interfaces. The results of the study showed that the extent of fun and learning are associated with the physical engagement of the player through an interface. As an implication from the study, the result recommend that the level of user engagement is realized by an effective user interface, and the level of physical engagement is determined by the level of authenticity bridged by the user interface.

• Journal of International Academy of Physical Therapy Research
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• v.2 no.1
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• pp.229-236
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• 2011

The purpose of this study was to comparatively analyze the active stability of shoulder joints according to the frequency of overhead motions, such as serving and spiking, engaged in by female professional volleyball athletes who play different positions, and to provide the results as the basic data for developing exercise programs to prevent shoulder joint injuries. The subjects of this study were 50 Korean female professional volleyball players and positions were as follows: left and right attackers, centers, setters, and liberos. The external rotation and internal rotation muscle strength and muscle strength ratios of the dominant and non-dominant arms of all subjects were measured using Biodex. The results of this study are as follows: Frist, no significant differences were found in the internal and external rotation muscle strength of the dominant and non-dominant arms between positions. Second, for the shoulder joint muscle strength ratio of the dominant arm, by position, the setter showed significantly greater stability compared to the other positions. Third, for the shoulder joint muscle strength ratio of the non-dominant arm, by position, no significant difference in stability between positions was found. Fourth, it was found that the dominant arm had significantly greater instability of the shoulder joint than the non-dominant arm for attackers and centers, but no significant difference was found for setters and liberos. This study comparatively analyzed the muscle strength ratios of the external/internal rotations and dominant/non-dominant arms, which can determine the stability of the shoulder joints between female professional volleyball playing positions that engage in jumps and spikes using only the dominant hand and positions that do not.

• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.353-379
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• 2020

The 2032 South-North Joint Olympics is an agreement between the two Koreas. Through this, various efforts are needed to improve new inter-Korean relations and co-prosperity on the Korean Peninsula. The purpose of this study is to proceed with the 203 South-North Joint Olympics. This study was developed by literature reserch methods. The result of this study are as follows. First, Seoul-Pyongyang soccer exchange game will be promoted. Second, the International Peace Cup a relay race(Marathon) will be held. Third, Korea Peace Cup International Table Tennis Championships will be held. Fourth, I propose holding the Korea Sports Science Forum. Fifth, about 16-17 events are propose for North Korea to host the 2032 South-North Joint Olympics. Sixth, the decision to host the 2032 Summer Olympics is expected in 2022 or 2023. Seventh, it is necessary to promote the Inter-Korean Social Association cultural Exchange and Cooperation Committee or the Special Committee for the Promotion of the Inter-Korea Sports Exchange and Cooperation. Eighth, it is necessary to implement a five-year plan to promote Inter-Korea sports Exchange Cooperation or a five-year plan for Inter-Korea sports Exchange and Cooperation. Ninth, the North Korea player registration system will be promote to the South Korean K-1 League. Ten, suggest sports exchange and cooperation ahead of time. Eleventh, train experts on North Korean sports or exchange and cooperation. Finally, the South-North Korea sports exchange Agreement will be promoted. It also promotes the Inter-Korea sports Exchange and Cooperation Support Act.