• 한국측량학회지
• /
• 제30권4호
• /
• pp.343-352
• /
• 2012

본 연구에서는 위성기준점의 안테나 교체로 인한 수직위치 변동량을 산출하기 위해 위성기준점의 데이터처리에 의해 산출된 좌표를 이용하는 방법을 사용하였다. 이를 위해 안테나 교체 전과 후의 위성기준점의 데이터를 정밀하게 처리하여 높이좌표를 산출하고, 안테나 교체 전후에 산출된 높이좌표 차이를 계산하는 방법으로 안테나의 수직위치 변동량을 산출하였다. 본 연구에서 산출된 수직위치 변동량을 적용하여 안테나교체 전후의 데이터를 처리한 결과 두 기간동안 산출된 수직좌표의 반복재현성(repeatability)은 평균적으로 7.9mm로 계산되었다. 이는 수직위치 변동량을 적용하지 않은 경우의 23.5mm에 비해 상당히 개선된 결과이며, 안테나의 교체 이전의 데이터처리 결과의 반복재현성과 유사한 수준인 것으로 판단되었다.

• 한국운동역학회지
• /
• 제27권2호
• /
• pp.109-116
• /
• 2017

Objective: This study aimed to investigate the relationship between leg stiffness and kinematic variables according to load while running. Method: Participants included eight healthy men (mean age, $22.75{\pm}1.16years$; mean height: $1.73{\pm}0.01m$; mean body weight, $71.37{\pm}5.50kg$) who ran with no load or a backpack loaded with 14.08% or 28.17% of their body weight. The analyzed variables included leg stiffness, ground contact time, center of gravity (COG) displacement and Y-axis velocity, lower-extremity joint angle (hip, knee, ankle), peak vertical force (PVF), and change in stance phase leg length. Results: Dimensionless leg stiffness increased significantly with increasing load during running, which was the result of increased PVF and contact time due to decreased leg lengths and COG displacement and velocity. Leg length and leg stiffness showed a negative correlation (r = -.902, $R^2=0.814$). COG velocity showed a similar correlation with COG displacement (r = .408, $R^2=.166$) and contact time (r = -.455, $R^2=.207$). Conclusion: Dimensionless leg stiffness increased during running with a load. In this investigation, leg stiffness due to load increased was most closely related to the PVF, knee joint angle, and change in stance phase leg length. However, leg stiffness was unaffected by change in contact time, COG velocity, and COG displacement.

• 한국운동역학회지
• /
• 제20권4호
• /
• pp.355-364
• /
• 2010

The purpose of this study was to investigate the kinematical analysis of T-stop motion by inline skate rolling speed. Six subjects were participated in the experiment(age: $35.0{\pm}3.3$ yrs, weight: $72.70{\pm}5.1\;kg$, height: $176.30{\pm}3.1\;cm$, career: $10.00{\pm}2.5$ yrs). The study method adopted 3-dimensional analysis and 2 cameras for filming to analyze the required displacement of center of mass, displacement of right and left hip joint, displacement of right and left knee joint, displacement of trunk tilt using by APAS. The results were as follows; In anterior-posterior displacement of COM, the faster rolling speed, the longer displacement at phase 2. In vertical displacement of COM, the faster rolling speed, the lower displacement. In medial-lateral displacement of COM, there was no significant on rolling speed. In angular displacement of right thigh segment, the faster rolling speed, the bigger displacement in X and Z axis. In angular displacement of left thigh segment, the faster rolling speed, the lower displacement in X axis. In angular displacement of right shank segment, the faster rolling speed, the bigger displacement in Z axis. In angular displacement of left shank segment, the faster rolling speed, the bigger displacement in X and Y axis. In angular displacement of trunk segment, the faster rolling speed, the bigger displacement in Z axis.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
• /
• pp.213-216
• /
• 1997

The Maxwell displacement current was investigated in the connection with phase diagram of monolayers on a water surface. We measwed the displacement current of 8A5H monolayers on the water surface. The displacement current generated during 8A5H monolayers compression. Also, displacement current pulses were found to be generated when isomerizations were induced in 8A5H monolayers by irradiation with ultraviolet light ($lambda_1=340nm$) and visible light($lambda_2=450nm$).

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2005년도 춘계 학술발표회 논문집
• /
• pp.1442-1447
• /
• 2005

Based on the field measuring data obtained from excavation sections in Inchon International Airport project, the relationships between the horizontal displacement of sheet-pile walls and the deformations of soft ground around the excavation were investigated. The horizontal displacements of walls according to supporting method are largely occurred in order of anchors, anchors with struts, and struts. The depths of maximum horizontal displacement are varied with supporting systems. If the stability number shows lower than ${\pi}$, the maximum horizontal displacement and the velocity of maximum horizontal displacement are respectively developed less than 1% of excavation depth and 1mm/day. When the stability number shows lower than ${\pi}+2$, the maximum horizontal displacement and the velocity are respectively developed less than 2.5% of excavation depth and 2mm/day. Also, when the stability number shows more than ${\pi}+2$, the maximum horizontal displacement and the velocity are rapidly increased.

• 한국운동역학회지
• /
• 제27권3호
• /
• pp.171-179
• /
• 2017

Objective: The purpose of this study was to perform a kinematic and kinetic analysis of double-under jump rope technique according to skill level and sex. Method: Participants comprised a skilled group of 16 (9 males, 7 females), and an unskilled group of 16 with 6 months or less of experience (9 males, 7 females). Five consecutive double-under successes were regarded as 1 trial, and all participants were asked to complete 3 successful trials. The data for these 3 trials were averaged and analyzed after collecting the stable third jump in each trial. The variables used in the analysis included phase duration, total duration, flight time, vertical toe height, stance width, vertical center of mass displacement, and right lower limb ankle, knee, and hip joint angles in the sagittal plane during all events. Results: The skilled group had a shorter phase and total duration and a shorter flight time than the unskilled group. The vertical center of mass displacement and ankle dorsiflexion angle were significantly smaller in the skilled group. The male group had a shorter phase duration than the female group. The vertical toe height was greater, the stance width was smaller, and the ankle and hip flexion angles were smaller in the male group. Conclusion: Variables that can be used to distinguish between skill levels are phase and total duration, flight time, vertical center of mass displacement, and ankle dorsiflexion angle. Differences between sexes in double-under jump rope technique may be related to lower limb flexion angle control.

• International Journal of Precision Engineering and Manufacturing
• /
• 제4권5호
• /
• pp.41-46
• /
• 2003

Electronic Speckle Pattern Interferometry (ESPI) has been recently developed and widely used because it has the advantage of being able to measure surface deformations of engineering components and materials in industrial areas without contact. The speckle patterns formed with interference and scattering phenomena can measure not only the out-of-plane but also the in-plane deformations. Digital image equipment processes the information included in the speckle patterns and displays the consequent interferogram on a computer monitor. In this study, the experimental results of a canti-levered plate using ESPI were compared with those obtained from the simple beam theory. The ESPI results of the canti-levered plate, analyzed by 4-step phase shifting method, are close to the theoretical expectation. Similarly, out-of-plane displacements of a spot welded canti-levered plate were also measured by ESPI with 4-step phase shifting technique. The phase map of the spot welded canti-levered plate is quite different from that of the canti-levered plate without spot welding.

• 한국운동역학회지
• /
• 제13권3호
• /
• pp.67-79
• /
• 2003

The purpose of this study is to investigate the effective skill motion through the kinematic analysis of the Yurchenko Streched motion in new horse vaulting. The subjects in this study were 3 male gymnasts who were ranked as national athletes. After the 3D motion analysis, kinematic variables were analyzed to comparison with the difference between this study and the previous study(Yang, D. Y and Lee, C. S, 1999). As a result, the following conclusions was drawn; 1. In the board contact phase, this study showed a shorten contact time to maintain in condition highly extension of hip and hee angle than the previous study. 2. In the pre-flight phase, this study appeared more shortly flight duration time and horizontal flight displacement than the previous study. 3. In the horse contact phase, the contact duration time and horizontal displacement of COG shortened than the previous study, but appeared to the fast horizontal and vertical velocity and highly extension of shoulder an. 4. In the post-flight phase, a stable horse contact appeared to the increase of the flight duration time and the apex height during the post-flight. And it showed that these results have a stable and good landing.

• 전력전자학회논문지
• /
• 제9권2호
• /
• pp.178-186
• /
• 2004

본 연구에서는 3상 RCD(Random Pulse Centered Displacement) PWM기법에 비하여 구현이 용이하고 스위칭 주파수의 정수배 스펙트럼의 광대역화와 선형화의 효과가 우수한, 2상 RCD-PWM을 제안하였으며, 그 파워 스펙트럼을 비교하고 있다 종전의 3상 RCD-PWM과 제안된 2상 RCD-PWM을 구현하기 위하여, 16비트 고성능 마이크로 컨트롤러 SAB-Cl67이 사용되었다 SAB-C167에 의하여 각 변조 구간에서의 듀티비를 구한 후, 선형 랜덤 발생기를 이용하여 균일한 확률 분포로 각 상의 펄스의 위치를 재배치하였다. 제안된 2상 RCD-PWM에 의한 모터전압과 전류 그리고 직류링크 전류의 파워 스펙트럼 및 모터의 가청 스위칭 소음 효과를 종전의 3상 RCD-PWM과 비교 검토하였다

• Journal of Power Electronics
• /
• 제19권6호
• /
• pp.1380-1392
• /
• 2019

Input filters are very important to matrix converters (MCs). They are used to improve grid side current waveform quality and to reduce the input voltage distortion supplied to the grid side. Due to the effects of the input filter and the output power, the grid side power factor (PF) is not at unity when the input power factor angle is zero. In this paper, the displacement angle between the grid side phase current and the phase voltage affected by the input filter parameters and output power is analyzed. Based on this, a new grid side PF unity compensation method implemented in the indirect space vector pulse width modulation (ISVPWM) method is presented, which has a larger compensation angle than the traditional compensation method, showing a higher grid side PF at unity in a wide output power range. Simulation and experimental results verify that the analysis of the displacement angle between the grid side phase current and the phase voltage affected by the input filter and output power is right and that the proposed compensation method has a better grid side PF at unity.