비압축성 점성 유체의 등가 유한요소 모델 축소

정익수(Iksu Jeong),김의영(Euiyoung Kim),조맹효(Maenghyo Cho) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.5

중학교 공기소총 선수의 운동학적 변인이 고득점에 미치는 영향

정익수(Jeong, Ik Soo),이진(Lee, Jin) 한국코칭능력개발원 2019 코칭능력개발지 Vol.21 No.2

타구 방향에 따른 테니스 스매시 동작의 근전도 분석

정익수(Jeong, Ik-Soo),이동진(Lee, Dong-Jin) 한국체육과학회 2016 한국체육과학회지 Vol.25 No.4

The purpose of the present study is to analyze the behavior of a male university Tennis player’s arm muscle which is the main agonistic muscle used during the smashing move, and to provide quantitative and scientific basis to the first-line leaders instructing the Tennis players. In the game of Tennis, sending the Tennis ball to a spot, which is difficult for the opponent player to response and take measure, determines the winner of the game. The result of the present study which is significant, in that it analyzed the expression of force during the smashing move, can be utilized by the first-line instructors and coaches. The result of this study is as follows. The muscular activity in the first interval showed that the radial flexors of wrist (FC) act as the agonistic muscle, followed by the bicephalus brachii (BM). In the second interval, only the radial flexor of wrist (FC) showed higher counter-cross than the cross. In the third interval, the radial flexor of wrist acted as the agonistic muscle. About the peak values during the entire intervals, the muscle activity of cross-hitting was high at the deltoid, and at the triceps on the outside of the greater pectoral, while the counter-cross hitting showed its peak at the biceps and radial flexor. Along with the multilateral analysis of smash moves with different hitting direction, the training of agonistic movements and appropriate training method will help players to express an optimized smashing move.

초등체육영재의 수직점프 수행 결과에 대한 운동역학적 분석

정익수(Ik Su Jeong),오정환(Cheong Hwan Oh),이동진(Dong Jin Lee) 한국체육교육학회 2012 한국체육교육학회지 Vol.17 No.2

체육영재에 선발된 D광역시 초등학교 저학년(2,3학년) 23명과, 고학년(4,5학년) 26명의 아동들을 대상으로 본 연구에서는 운동역학적인 변인으로 지면반력을 측정하고, 신체적 요인인 근력과 관련하여서는 무릎의 최대 각속도 및 신장, 좌고, 체중을 비교 분석하였으며, 운동학적인 변인으로는 무릎관절의 최소각을 변인으로 하여 수직점프를 수행한 결과 다음과 같은 결론을 얻었다. 첫째, 초등학교 저학년과 고학년의 두 집단 간에 신체적 특성은 모두 유의한 차이가 나타났다. 둘째, 수직점프수행과 관련하여 측정된 변인 간에는 수직점프 수행력에서만 두 집단 간 유의한 차이가 나타났다. 셋째, 수직점프 수행력과 신체적 특성과의 상관관계는 초등학교 고학년에서만 신장과 높은 상관을 보였다. 넷째, 수직점프 수행력과 최대 수직힘, 무릎관절의 최대각속도, 무릎관절의 최소각과의 상관관계는 초등학교 저학년 집단에서만 무릎관절의 최소각이 가장 높은 역상관 관계를, 무릎관절의 최대 각속도는 높은 상관관계를 보였으며, 고학년 집단에서는 세 변인 모두 수직점프 수행력과 낮은 상관관계를 보였다. With the subjects of 23 lower-grade elementary schoolers (2nd and 3rd grade) and 26 upper-grade elementary schoolers (4th & 5th grade) who are selected as athletically gifted children, the study measured kinetic variables with ground reaction force, conducted a comparative analysis on angular velocity of knees, heights, sitting heights and weights regarding strength, a physical factor, and reached the following conclusions after performing vertical jumping with the variables of the minimum angle of knee joints. First, physical characteristics of the both groups of elementary school low-graders and upper graders showed significant differences. Second, the two groups showed a significant difference only in vertical jumping performing abilities among the variables measured in relation to vertical jumping performance. Third, the correlation between vertical jump performance and physical characteristics is found to be high only in the upper grade elementary schoolers. Fourth, in terms of the correlation between vertical jumping performance and maximum vertical force, the maximum angular speed of knee joints and the minimum angle of knee joints, only minimum angle of knee joints showed the highest inverse correlations followed by the high correlation of maximum angular speed of knee joints while all the three variables showed low correlation with vertical jumping performance.

스트레인게이지가 부착된 충격력 측정 장비 개발

정익수 ( Ik So Jeong ) 한국운동역학회 2012 한국운동역학회지 Vol.22 No.2

The purpose of this study was to develop an impact force measurement device in order to facilitate the acquisition of quantitative data for the analysis of various sporting events. The device was designed to include cylindrical aluminum supports of 220 mm diameter, which allows mounting and dismounting of the device on walls and frames, In addition, a hard sponge for impact absorption, as well as 4 springs, were attached to the plate, Both were attached to prevent psychological variables and injuries, When a subject applies force on the device, accurate data about the maximum repulsive force is acquired in real time, with a lag of only 0.001 s. The device was calibrated in four steps: (1) increase, (2) increase, (3) increase-decrease, and (4) increase-decrease. The maximum relative expanded uncertainty was 0.166%, indicating that the impact force measurement was sufficiently reliable. The proposed device can be applied to various sportin g situations and is expected to be useful for studying kinetics.

전체 변위장 측정을 통한 변형률 구배 모델의 구성 변수 식별

정익수(Iksu Jeong),조맹효(Maenghyo Cho) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12

Strain gradient theory have been developed recently to demonstrate some phenomena such as size effect that classical continuum mechanics could not predict. Despite of the theoretical development of strain gradient theory, it was difficult to use this theory in practical issues since constitutive models of this theory contain additional parameters which are almost impossible to be identified experimentally. The recent developed full-field measurements techniques like digital image correlation can enable experimental identification of the constitutive parameters in strain gradient theory because it directly couples experiments and numerical analysis. In this research, we developed an identification method using full-field displacement measurements for materials with strain gradient effect. The accuracy and noisedependency of proposed method are tested in the examples of center-cracked specimen and plate with a circular hole.

기합소리 유형에 따른 H-reflex 변화와 MVIC변화 분석

정익수 ( Ik Su Jeong ),오정환 ( Cheong Hwan Oh ),이동진 ( Dong Jin Lee ),이건희 ( Gun Hee Lee ),이진 ( Jin Lee ) 한국운동역학회 2009 한국운동역학회지 Vol.19 No.4

코칭머신 훈련이 사격선수의 경기력 향상에 미치는 연구

정익수(Jeong, Ik-Soo) 한국체육과학회 2020 한국체육과학회지 Vol.29 No.2

This study was conducted to investigate the effects of the target duration on the target adherence ability of the shooters through eight weeks of training, using a coaching machine (SCATT) that can monitor the real-time relationship between the movement of the gun and the score of the gun that originated from the stability of the posture, and the percentage of the duration of the stop in the circle of 10.0 and 10.5.,This study aims to present quantitative and objective data for the preparation of training programs for improving the performance of shooting players and the formation of personalized routines of players. The subjects of this study were six students who were selected as air rifle shooters in D middle school, who were registered as players in the Korean Shooting Federation, who expressed their recommendation or voluntary participation intention. In conclusion, first, the time required was about 1.59s in the post-test, but there was no statistically significant difference. Second, the ratio of moving time within 10.0 points was shown as %, and the result showed that 44.56% increased in the post-variable and statistically significant. Third, the ratio of moving time within 10.5 points of the aiming point was %, and the result showed that the post-variable increased by 24.52% and statistically significant. Fourth, the total length of the gun that the target point moved showed a short displacement of 3.10mm in the post-variable, but there was no statistically significant difference.

전체 변위장 측정을 활용한 머신러닝 기반의 기계적 물성 식별

정익수(Iksu Jeong),안종원(Jongwon An),조맹효(Maenghyo Cho) 대한기계학회 2020 대한기계학회 춘추학술대회 Vol.2020 No.12

크라우칭 스타트시 반발력과 반응시간 측정을 위한 향상된 정밀센서 개발

이정태(Jeong Tae Lee),오정환(Cheong Hwan Oh),정익수(Ik Su Jeong) 한국사회체육학회 2011 한국사회체육학회지 Vol.0 No.46

This study intends to develop a more improved starting block precision sensor for enhancement of performance and motor mechanical analysis in short-distance track race. The production involved attaching strain gauge to the symmetric beam structure for the commercial starting block, which was found to show 5 times the improved effects, indicating that the beam structure devised in this study is effective, and it appears that credible measurement can be achieved. In the future, additional study will be conducted on the influence of training using starting block sensor on starting position correction and record improvements targeting the short-distance track athletes.