• 제어로봇시스템학회논문지
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• 제22권1호
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• pp.53-58
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• 2016

Various jumping robot platforms have been developed to carry out missions such as rescues, explorations, or inspections of dangerous environments. We suggested a jumping robot platform using energy conversion of the elastic body like the bar of a pole vault, which is the main part in which elastic force occurs. The compliant link was optimized by an optimization method based on Taguchi methodology, and the robot's leaping ability was improved. Among the parameters, the length, width, and thickness of the link were selected as design variables first while the others were fixed. The level of the design variables was settled, and an orthogonal array about its combination was made. In the experiment, dynamic simulations were conducted using the DAFUL program, and response table and sensitivity analyses were performed. We found optimized values through a level average analysis and sensitivity analysis. As a result, the maximum leaping height of the optimized robot increased by more than 6.2% compared to the initial one, and these data will be used to design a new robot.

• 제어로봇시스템학회논문지
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• 제7권12호
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• pp.1015-1023
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• 2001

error behaviour can be considered as a linear combination of low amplitude random noise and abrupt jumps. The reason of jump appearance can be explained by the semi-shading effects(buildings, trees), jamming, high dynamic of vehicle and so on. This study describes the stand-alone GPS error jump smoothing algorithm which is developed based on the scalar adaptive filter. The algorithm consists of the coarse jump smoothing and the fine jump smoothing. On the coarse smoothing step, GPS velocities or position differences are used as the measurement for the scalar adaptive filter. The purpose of adaptive filter is to smooth the jump errors. The coarse positions are detennined by the integration of smoothed velocities. On the fine smoothing step, the differences between GPS positions and the coarse positions are smoothed by another scalar adaptive filter. The reason of fine smoothing is based on the facts that smoothing accuracy depends on the variance ofusefuJ signa\. The coarse smoothing which deal with the difference of positions provides the rough error removing. So the coarse smoothed velocities can have much more low amplitude than the raw ones. The fine smoothing procedure provides high quality of filtering process. Simulation results show the efficiency of proposed scheme.

• 대한조선학회논문집
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• 제36권4호
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• pp.9-20
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• 1999

기하학적 형상과 유동의 해를 B-스플라인으로 표현하는 2차원 고차 패널법이 개발되어 수중익 문제의 해석에 적용되었다. 제어점이 패널내에 놓이는 경우, 고차의 다이폴과 쏘오스에 의해 유기되는 자기 유기 포텐셜의 특이 거동을 제거하기 위하여 피적분 함수를 특이 부분과 비특이 부분으로 나누어, 특이 부분을 해석적인 적분으로 비특이 부분은 정도 높은 Gauss 구적법으로 계산함으로써 유기 포텐셜을 정도 높게 구할 수 있음을 보였다. 또한, 날개 뒷날에서의 압력 점프의 값이 명시적으로 영이 되도록하는 동역학적 Kutta 조건식을 도입하고, 이의 적용이 안정된 해를 보장함을 확인하였다. 수치 실험을 통하여, 제안된 수치해석 기법이 안정적이고 정확한 해를 줌을 확인하였으며, 특히 저차 패널법과 비교하여 적은 수의 패널로 동일한 정도를 유지할 수 있음을 보였다.

• 한국해양공학회지
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• 제23권4호
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• pp.12-18
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• 2009

The present study focused on the compressibility of partially filled fluids in a sloshing tank. Filling ratios ranging from 18% to 26% were used to find compressible impact on a vertical wall. The model test was for 1/25 scale of a 138 K LNGC cargo tank. To investigate the two dimensional phenomenon of sloshing, a longitudinal slice model was tested. A high speed camera was used to capture the flow field, as well as the air pocket deformation. The pressure time history synchronized with the video images revealed the entire compressible process. Three typical impact phenomena were observed: hydraulic jump, flip through, and plunging breaker. In particular, the pressure time history and flow pattern details for flip through and plunging breaker are presented.

• 한국운동역학회지
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• 제20권4호
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• pp.407-414
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• 2010

The purpose of this study was to evaluate the effect of taping-tape with or without using spiral taping on vertical jump. The subjects for this study were about 20 years old healthy male college students without muscloskeletal diseases. Data for EMG activity and Ground Reaction Force(GRF) were estimated at three knee angles(i.e., 45, 90 & full degree). As a result, there was no statistical significance in max GRF at 90 and full degree regardless of spiral taping-tape. On the other hand, statistical significance was found when vertically jumping at 45 degree knee angle(p<.05). All the data for EMG activity at the three knee angles were not statistically significant, but there was a trend for a decrease in average EMG activity in elector spinae & Medial gastrocnemius at 90 degree knee angle. Based on these data, initial flexor action of knee was stabilized with spiral taping-tape when vertically jumping, resulting in improved muscular activity in Medial gastrocnemius. In conclusion, taping technique for jumping ability associated muscles like quadriceps is also required to develop.

• 한국운동역학회지
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• 제17권3호
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• pp.23-29
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• 2007

The purpose of this study were to investigate the differences between female and male basketball players in knee neuromuscular biomechanical factors during basketball rebound jump. Twelve high school female ($17.9{\pm}0.8years$) and twelve male ($19.0{\pm}1.6years$) basketball players rebound jumped for maximal vertical height to sufficiently stress the anterior cruciate ligament. Kinematic and ground reaction data were collected and combined with inverse dynamics to estimate the knee extensor and abductor torque. The EMG data from the biceps femoris and rectus femoris was used to estimate the ratio of quadriceps muscle activity. Female athletes showed more reduced knee flexion at foot contact, more increased knee abduction, extensor and abductor knee joint torque at foot contact, and quadriceps ratio at stance phase than those of male athletes. In conclusion, Female athletes showed differences in knee neuromuscular biomechanical factors than male athletes during basketball rebound jump.

• 한국운동역학회지
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• 제32권3호
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• pp.80-86
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• 2022

Objective: The purpose of this study was to investigate the effects of three rotational jump conditions (standing jump, left rotational jump and right rotational jump) on stability through center of pressure (COP) and EMG variables analysis. Method: A total of 16 college students (age: 24.13 ± 7.17 years, height: 169.24 ± 8.23 cm, weight: 65.65 ± 13.88 kg) participated in this study. The study used wireless two COP plates and wireless eight channel EMG. The analyized variables were 11 variables for COP and RMS for EMG, which were analyzed using one-way analysis of variance with repeated measures according to three rotational jump conditions. Results: Among the COP variables, left rotational jump (LRJ) and right rotational jump (RRJ) were larger than standing jump (SJ) for left and right amplitude, area, total displacement, and average velocity for both feet among the variables of COP, and for area of the left foot, RRJ was larger than that of SJ. Among the EMG variables, there was no statistical difference between the muscle activations, but the muscle activity was significantly higher in the order of RRJ, LRJ, and SJ according to direction of rotation. Conclusion: Although the results of COP and EMG were not consistent through this study, it can be expected that the differences in COP was due to the amount of rotation during rotational jump-landing in the left and right directions, and that the EMG is determined by the lateral movements required for rotation.

• 대한조선학회논문집
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• 제30권1호
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• pp.73-86
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• 1993

균일 유동장 중에서 작동 중인 선박 프로펠러의 정상 성능 추정을 위하여 포텐셜을 기저로한 패널법을 기술하고 있다. 본 방법은 법선 다이폴과 쏘오스를 프로펠러 날개, 허브, 후류면에 분포함으로써 다이폴의 세기를 미지수로 하는 적분방정식을 얻고, 이산화과정을 거쳐 수치적으로 계산된다. 비평면 사각형 패널위에 있는 법선 다이폴에 의해 유기되는 포텐셜을 구하기 위하여 쌍곡면 요소를 채택하고 있다. Kutta 조건은 반복계산에 의해 날개 뒷날에서의 압력 점프를 없앰으로써 만족시킨다. 수렴성을 보이기 위하여 상세한 수치시험을 수행하였으며, 동시에 후류면 모형화가 성능에 미치는 영향도 조사하였다. 프로펠러의 단독 모형시험 결과와 수치추정 결과가 잘 일치하는 것을 보였다.

• 한국운동역학회지
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• 제33권3호
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• pp.85-93
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• 2023

Objective: This study examined differences in joint kinematics and movement variability of lower extremity between adolescent athletes with and without lateral ankle sprain (LAS) history during drop vertical jump. Method: Fourteen adolescent athletes with LAS history and 14 controls participated in this study. The independent variable was group while dependent variables were 3D joint kinematics and movement variability of hip, knee, and ankle joint. Ensemble curve analyses were conducted to identify differences in movement strategies between two groups. Results: The LAS group showed that greater eversion during jump phase compared with the control group. Additionally, less movement variability was found in the LAS group during the pre-landing and jump phases in ankle and hip joints compared with the control group. Conclusion: The LAS group may adapt the environmental constraints by reducing the movement variability in ankle and hip joints. However, training programs focusing on recovery of ankle function should be emphasized after LAS because excessive pronation for prevention of LAS during the jump phase may result in reduced performance.

• 한국HCI학회논문지
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• 제9권2호
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• pp.13-21
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• 2014

줄넘기 운동은 간단하면서도 매우 효과적인 운동 효과를 갖고 있지만, 높은 강도의 단조로운 운동 패턴으로 인해 지속적으로 운동을 시행하기 어려운 단점이 있다. 한편 줄넘기를 할 때 수반되는 운동에너지로부터 전기에너지를 생성하는 자가발전이 가능하며, 이전 연구에서 자가발전이 가능한 에너지 자립형 줄넘기로써 그 가능성을 확인한 바 있다. 본 연구에서는 에너지 자립형 줄넘기의 내부에 자체 생산된 전력으로 구동되는 초소형 임베디드 시스템을 내장하여, 줄넘기 운동 중의 가속도를 측정하고 스마트폰으로 무선 전송하도록 하였다. 스마트폰에서는 전용 앱을 통해 전송받은 가속도 데이터로부터 사용자의 점프를 감지하여 음악 줄넘기를 접목한 게임 콘텐츠와 실시간 연동할 수 있도록 하였다. 개발된 스마트 줄넘기 프로토타입은 사용자 테스트를 통해 줄넘기 운동의 지속적인 동기부여 방법으로써 유용함을 확인 할 수 있었으며, 축적된 운동 데이터를 기반으로 사용자에게 체계적인 피드백을 제공함으로써 줄넘기 운동의 효과를 보다 높일 수 있을 것으로 기대한다. 아울러 건전지 교체가 불필요한 에너지 자립 특성은 비용 절감과 더불어 사용성과 지속가능성 향상에도 크게 기여할 수 있을 것이다.