• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 합동춘계학술대회 논문집 전기물성,응용부문
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• pp.191-192
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• 2008

In this paper, we investigated on the characteristics and assessment of the insulators damaged by hitting tester(ST-100, Sharp-Eng, KOR). It made that an apparatus act on KS C 3801 for the damaged characteristics and assessment of insulators according to external scattering objects. There are selected 255mm glass insulators and 254mm porcelain insulators as the specimen. The hitting angles of the damaged insulator by pendulum weight are at $72^{\circ}$. At these points, velocity of pendulum weight is about 3.04m/sec and the force is 58.16N. At the hitting angle of 26 degrees, glass insulator is diffused the vibration within it but porcelain insulator is not. The inside vibrations of glass insulator and porcelain insulator are as like as two at the hitting angle of 53 degrees. The damaged glass insulator at the hitting angle of 72 degrees hardly is not diffused.

• 한국운동역학회지
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• 제15권1호
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• pp.63-74
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• 2005

J. R. PARK. The Analysis of Electrimyography and Kinematic of Kumdo Player's Head Hitting. Korean Journal of Sport Biomechanics, Vol. 15, No. 1, pp. 63-74, 2005. The purpose of this study were to describe and compare the selected electromyographical muscle activities of arm and kinematic data of kumdo player's head hitting. Using surface electrode electromyography, we evaluated muscle activity in 6 male players during head hitting motion. Surface electrodes were used to record the level of muscle activity in the carpi radialis, deltoid, triceps, biceps muscles during the player's head hitting. These signals were compared with %RVC(Reference voluntary contraction) which was normalized by IEMG(Integrated EMG). The kumdo head hitting motion was divided into two phases: back swing, down swing. we observed patterns of arm muscle activity throughout two phases of the kumdo head hiting The results can be summarized as follows: right elbow angle had decreased and left deltoid muscle's activation had higher than right deltoid muscle's activation, right carpi radialis muscle's activation had higher than left carpi radialis muscle's activation in back swing phase, knee angle had decreased and left triceps muscle's activation had higher than right triceps muscle's activation, right deltoid muscle's activation had higher than left deltoid muscle's activation, right carpi radialis muscle's activation had higher than left carpi radialis muscle's activation in down swing phase

• 콘크리트학회논문집
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• 제17권3호
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• pp.313-322
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• 2005

최근 들어 리모델링시장이 점차 신축시장의 대체시장으로 부각되고, 재건축아파트에 대한 안전진단의 문제가 사회의 주요 관심사가 되면서 기존 콘크리트 구조체의 상태에 대해 체계적이고 과학적인 구조물 진단 및 평가가 요구되고 있으며, 비파괴 시험방법에 의한 콘크리트 압축강도를 추정하기 위한 데이터의 신뢰성에 대한 중요성이 점점 증대되고 있다. 본 연구에서는 선 타격 개념의 반발도 시험기를 적용하여 콘크리트 압축강도 추정의 신뢰성을 향상시키는 방안을 모색하고, 재령 및 타격각도에 따라 선 타격 반발도 시험기에 적용할 수 있는 압축강도 추정식을 제안하고자 하였다. 연구 결과, 선 타격 반발도 시험기는 재령별, 타격각도별로 별도의 추정식을 제안하는 것이 콘크리트 압축강도 추정의 신뢰성을 향상시키는데 긍정적인 것으로 나타났으며, 압축강도와 반발도 사이의 상관관계는 초기 및 중기재령, 그리고 타격각도별로 초기재령 $-45^{\circ}$를 제외한 모든 부분에서 선 타격 반발도 시험기 25mm가 가장 높은 것으로 나타나 기존의 슈미트해머에 비해 콘크리트 압축강도 추정의 신뢰성을 높일 수 있는 방안이 될 것으로 분석되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.475-476
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• 2008

This paper is an experimental test for the close examination of breakdown causes of glass insulators using at the electric rail-road. The glass insulator is estimated the mechanical performance according to hitting test(ST-100, Sharp-Eng, KOR) that is based on KSC 3810. Insulators is damaged by pendulum weight at the steps of hitting angles. Glass and porcelain insulators are broken at the hitting angle of $72^{\circ}$. From the these results, glass insulator absorbed the impact from the pendulum weight but on the porcelain insulator, it is not transmitted vibration by impact. Hereafter, these results are expected that is used the data for the assessment on breakdown cause of a glass insulator.

• 한국운동역학회지
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• 제20권1호
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• pp.25-32
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• 2010

This study was performed to investigate the kinematic factors on the head hitting motion based on weight change of bamboo swords in kumdo. The kinematic factors, needed time per phase, COB displacement and velocity, angle(wrist, elbow, shoulder joint, hip joint, knee joint), were analyzed by the 3-D motion analysis method against 6 male middle school athletes. The results were as follows. 1. The needed time of head hitting motion based on weight change of bamboo swords was shorter when weight was heavier. 2. The COB displacement of left/right was bigger when weight was heavier. the displacement of right foot was higher at backswing phase and impact phase when weight was heavier and at impact time when weight was lighter. 3. The COB velocity was faster at impact time when weight was heavier, the velocity of sword tip was fastest for each event with bamboo sword weight of 440 g. 4. The angle of left elbow was smaller at top of backswing and impact when weight was heavier, the angle of left shoulder was bigger when weight was heavier, the right knee angle was biger at start when weight was heavier, at impact when weight was lighter.

• 한국운동역학회지
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• 제13권2호
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• pp.49-63
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• 2003

For this study, four male university Taekwondo players were randomly chosen, between the weight categories of 60Kg and 80Kg. Their side kicks (yeop chagi), which are part of foot techniques, were kinematically analyzed in terms of the time, angle, and angular velocity factors involved with the kicks through the three-dimensional imaging. The results of the analysis are as fellows. 1. Time factor The first phase(preparation) was 0.48sec on average, accounting for 60% of the entire time spent; the second phase(the minimum angle of the knee joint) was 0.21sec on average, taking up 26% of the whole time spent; and the third phase(hitting) was 0.11sec on average, representing 14% of the entire time spent. 2. Angle factor In the first phase(preparation), rotating their bodies along the long axis, the players bended their hip and knee joints a lot, by moving fast in the vertical and horizontal directions, in the second phase(the minimum angle of the knee joint), the players continued to extend their bodies along the vertical axis, while pronating their lower legs and bending their hip and knee joints a lot to reduce the radius of gyration, and in the third phase(hitting), they extended their knee joints greatly so that the angle movements of their lower bodies shifted to circle movements. 3. Angular velocity factor In the first phase(preparation), the angular velocity of the hip and knee joints increased. while moving horizontally and rotating the body along the long axis; in the second phase(the minimum angle of the knee joint), the angular velocity increased by bending the hip and knee joints fast to reduce the rotation radios; and in the third phase(hitting), the angular velocity was found to have increased, by rotating the body along the long axis to increase the angular velocity and shifting the angular momentum of the pronated knee joint to the circular momentum.

• 한국운동역학회지
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• 제15권3호
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• pp.71-78
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• 2005

The purpose of this research was to conduct an analysis on the factors that determine the distance at the time of target swing based on the use of late hitting of outstanding college golfers to verify the difference between late hitting and the distance that target increases in regular swing and the distance. Then, this research conducts an analysis on the correlation between club head velocity, ball velocity, launch angle, back spin, meet ratio and distance that become kinematics variables at the time of target swing. To attain the above mentioned purpose, 25 outstanding college players with average experience and handicap of 6 years and 5, respectively, were targeted Comparative analysis on two swing that target increase in regular and the distance was conducted by used driver. When it pertained to two types of swing. analysis system comprised of an analytical software called the Science Eye of the Bridgestone and peripheries was used to define the relationship between variables of club head velocity, ball velocity, launch angle, back spin, meet ratio that become kinematics variables. As for the method of processing data pertaining to the factors that determine the distance, differences of distance by the type of swing was verified by using independent T-test that leveraged SPSS 120 statistics program. Moreover, level of correlation between variables that contribute to the increase in distance through relation of correlation, and analysis of tendencies was conducted to analyze tendency of non-distance to increase in accordance to the increase of each variable. Key results produced through this experiment are as follows: 1. Artificial late hitting for increased non-distance that targets skilled players had effect on increased the distance(p<. 05). 2 The drive distance is correlated with each measured variable that is positive correlation to ball velocity, club head velocity, meet ratio and relation of back spin and launch angle are negative correlation. ball velocity and club head velocity are very high correlated with drive distance(p<.01), back spin and distance are negative correlation(p<.01). 3. Among each measured variable increasing the club velocity is the most contribution, and ball velocity and meet ratio and the increasing launch angle and back spin is negative effect for increasing distance.

• 한국운동역학회지
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• 제24권1호
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• pp.11-18
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• 2014

The purposes of this study were to analyze the kinematics and electromyographic variables of the upper extremity for the backhand clear motion according to the type of hitting in badminton. Seven elite male university players were selected as the subjects. Four digital video cameras and Noraxon Telemyo 2400 were used to collect the 3D kinematics and electromyographic data. The results were as follows: 1) in the phase of impact, the time of motion for the overhead backhand clear was the longest, 2) in the event of impact, the distance of step toward X direction was the longest and the distance of step toward Y direction was the shortest for the overhead backhand clear, 3) in the event of backswing, the rotation angles of shoulder and pelvis and the flexion angle of shoulder for the overhead backhand clear were the biggest, 4) the maximum flexion angular velocity of shoulder and the maximum extension angular velocity of elbow for the overhead backhand clear were the biggest, and 5) in the phase of impact, mean EMG of the wrist flexor, triceps, and trapezius muscle for the overhead backhand clear was bigger than that for the underhand stroke and in the phase of follow-through, mean EMG of the wrist flexor and extensor, biceps, triceps, and trapezius muscle for the overhead backhand clear was the biggest.

• 한국운동역학회지
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• 제16권4호
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• pp.49-59
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• 2006

The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle according to sweep shot in ice hockey. The subjects of this study were five professional ice hockey players. The reflective makers were attached on anatomical boundary line of body. 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 LabVIEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and ice hockey stick were defined. 1. In three dimensional linear velocity of blade the Y axis showed maximum linear velocity almost impact, the X axis(horizontal direction) and the Z axis(vertical direction) maximum linear velocity of blade did not show at impact but after impact this will resulted influence upon hitting puck. 2. The resultant linear velocity of each segment of right arm showed maximum resultant linear velocity at impact. It could be suggest that the right arm swing patterns is kind of push-like movement. therefore the upper arm is the most important role in the right arm swing. 3. The three dimensional anatomical angular displacement of trunk in flexion-extension showed flexion all around the wrist shot. The angular displacement of trunk in internal-external rotation showed internal rotation angle at the backswing top and and increased the angle after the impact. while there is no significant adduction-abduction. 4. The three dimensional anatomical angular displacement of trunk showed most important role in wrist shot. and is follwed by shoulder joints, in addition the movement of elbow/wrist joints showed least to the shot. this study result showed upperlimb of left is more important role than upperlimb of right.

• 한국운동역학회지
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• 제16권4호
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• pp.95-103
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• 2006

The purpose of this study was to review the relevant literature about coaching and thereupon, survey the coaching methods used for golf lesson to reinterpret them and thereby, describe in view of kinetics the swing errors committed frequently by amateur golfers and suggest more scientific golf coaching methods. For this purpose, kinetic elements were divided into accuracy and power ones and therewith, the variables affecting such elements were identified. For this study, a total of 60 amateur golfer were sampled, and their swing forms were photographed with two high-speed digital cameras, and the resultant images were analyzed to determine the errors of each form kinetically, which would be analyzed again with the program V1-5000. The kinetic elements could be identified as accuracy, power and accuracy & power. Thus, setup and trajectory were classified into accuracy elements, while differences of inter-joint angles, cocking and delayed hitting. Lastly, timing and axial movement were classified into accuracy & power elements. Three errors were identified in association with setup. The errors related with trajectory elements accounted for most (6) of the 20 errors. Three errors were determined for inter-joint angle differences, and one error was associated with cocking and delayed hitting. Lastly, one error was classified into timing error, while five errors were associated with axial movement. Finally, as a result of arranging the errors into a cross table, it was found that the errors were associated with each other between take-back and back-swing, take-back and follow-through, back-swing and back-swing top, and between back-swing and down-swing. Namely, an error would lead to other error repeatedly. So, it is more effective to identify all the errors for every form and correct them comprehensively rather than single out the errors and correct them one by one.