• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 2003년도 ICCAS
• /
• pp.1344-1348
• /
• 2003

A precision micro-positioning system with a high displacement resolution and wide motion range has been required for industrialized applications in variety fields. This paper discusses the design of a precision micro-rotation stage with flexure hinges. Proposed system is applied to grinding machine for micro parts. Rotational motion is generated with this system. For this systems having a full rotation motion with high precision, a dual servo system with a coarse stage and a fine stage is proposed.

• 국제물리치료학회지
• /
• 제9권4호
• /
• pp.1676-1682
• /
• 2018

The purpose of this study was to investigate the short-term effects of lumbar rotational mobilization under the single-leg standing (SLS) position. Fifteen healthy individuals were recruited, and randomized to agroup of trunk rotational exercise (TRE) and lumbar rotational mobilization (LRM). Trunk twist rotational exercise was performed to the TRE group, and mobilization was applied to the LRM group on the lumbar spine. Velocity of the center of pressure (VCOP) and center of pressure (COP) for each participant were measured through SLS. COPs were not significantly increased or decreased after treatment in both groups. VCOPs also did not change considerably except on the right side when the eye was closed. There was no significant difference between COPs and VCOPs in two groups. This study suggests that trunk rotation exercise and lumbar rotation mobilization would have similar effects on balance ability.

• PNF and Movement
• /
• 제16권1호
• /
• pp.143-150
• /
• 2018

Purpose: The purpose of this study was to investigate the influence of opposite lower extremity lateral muscle activation by proprioceptive neuromuscular facilitation (PNF) exercise targeting the lower extremities. Methods: Nineteen patients with chronic hemiplegia volunteered to participate in this study. PNF flexion, abduction, and internal rotation patterns; initial, end range, and extension patterns; abduction and internal rotation patterns; and initial and end range patterns were applied to the dominant lower extremity. Activation of lateral muscles (multifidus, gluteus medius, tensor fascia lata, and peroneous longus) of the paralyzed leg was then measured by electromyography (EMG). Results: There were significant differences in lateral muscle activation, depending on the PNF pattern applied, with the differences more significant in flexion, abduction, internal rotation, and end range patterns. Conclusion: PNF flexion, abduction, and internal rotation patterns can improve lateral muscle activation of one leg in the standing position in the gait cycle.

• 한국자기학회지
• /
• 제5권5호
• /
• pp.561-566
• /
• 1995

Additional magnetooptical Kerr effect (AMOKE) was observed in several multilayer structures. For Fe/Pd and Co/Cu Multilayers, AMOKE enhanced the Kerr rotation in short wavelength side, while for Fe/Ag and FeSi/Cu multilayer systems the Kerr rotation enhancement appeared in long wavelength side. A number of ferromagnetic/nonmagnetic/ferromagnetic(FM/NM/FM) sandwiches showed that the AMOKE led to oscillations of Kerr rotation and Kerr ellipticity in certain wavelength range with changing NM layer thickness similar to the oscillatory interlayer coupling. The oscillation of effective optical constants related to the MOKE oscillation was observed for the first time. The mechanisms of the AMOKE were discussed.

• 대한산업공학회지
• /
• 제25권1호
• /
• pp.56-66
• /
• 1999

Shoulder joint is the most movable joint in human body with, at least, three degrees of freedom, since there are at least three bones and five joints involved in shoulder movement. Due to the complexity of the shoulder joint and the lack of appropriate anatomical data, modeling of the shoulder joint has been known to be extremely difficult. In many biomechanical models being used, shoulder joint is considered as a fixed point and it is also assumed that the shoulder joint does not noticeably move during the shoulder movement. However, such an assumption is not valid in real applications and causes inaccuracy, especially, in the area of workspace evaluation. The reachable area generated by a human becomes somewhat different from that of current models for those models fail to appropriately reflect the movement of shoulder joint's center of rotation. In this study, the location of the shoulder joint's center of rotation was obtained in relation to the location of humerus, on which a new model for reach envelope generation was developed for workspace evaluation. From the experiments conducted for three subjects, the initial location of the center of rotation was determined for each subject and subsequent changes in the instantaneous center of rotation were drawn as a function of flexion and abduction of the shoulder. Based on the regression analysis, the study suggested a new method for the generation of reach envelope. Comparisons were also made among real reach envelopes obtained from the experiment, the ones from the model, and the ones from the new method suggested in the study. As a result, the prediction errors incurred from the new method were significantly reduced when compared to the ones from the current approach.

• 대한정형도수물리치료학회지
• /
• 제29권2호
• /
• pp.23-29
• /
• 2023

Background: There is still controversy as to whether hip external rotation and dorsiflexion selectively activate the vastus medialis obliquus (VMO) during straight leg raise exercise. Due to the anatomical characteristics, hip adduction must be preceded to activate the VMO. In this study, the activities of the rectus femoris (RF), vastus lateralis (VL), VMO were measured by adding the hip adduction movement to the straight leg raise exercise with hip 45° external rotation and straight leg raise exercise with hip 45° external rotation and dorsiflexion. Through this, we want to find out whether the VMO is selectively activated. Methods: Thirteen healthy participants performed straight leg raise exercise with hip 45° external rotation, straight leg raise exercise with hip 45° external rotation and dorsiflexion, straight leg raise exercise with hip 45° external rotation and adduction, straight leg raise exercise with hip 45° external rotation and adduction and dorsiflexion was randomly performed. Through this, EMG data of the RF, VL, VMO were collected. Results: During the straight leg raise exercise, hip adduction increased the activity of the VMO and VL, no significant difference was found(p>.05). However, in the VMO/VL ratio, straight leg raise exercise with hip 45° external rotation and adduction and dorsiflexion activated the VMO and the VL at a ratio of about 1:1, It showed a significantly higher rate than straight leg raise exercise with hip 45° external rotation(p<.05). Conclusion: During the straight leg raise exercise, hip adduction is considered to be an important movement that can selectively induce the activity of the VMO. Therefore, follow-up studies on this should be conducted.

• 한국운동역학회지
• /
• 제19권4호
• /
• pp.779-791
• /
• 2009

본 연구의 목적은 원위지점에서 움직이는 실험 데이터를 이용하여 그 점들의 회전운동 순간 중심점을 분석하는 프로그램(Centering 1.0)을 개발하는 것이다. 이를 위해 수학적인 알고리즘을 정의하고, 물체의 운동에 대한 실험 데이터를 입력하여 회전운동 순간 중심점을 찾아내는 컴퓨터 프로그램을 구현하였다. 프로그램을 검증하기 위한 실험 데이터는 한명의 숙련된 여성골퍼의 피칭(40m 캐리)과 퍼팅(4m) 스트로크 시 클럽의 움직임으로 수집하였다. 그리고 이 데이터를 본 연구를 통해 개발된 회전운동 순간 중심점 분석 프로그램에 적용하여 클럽의 움직임 시 회전의 중심점을 찾고, 그 위치의 크기를 반지름으로 나타내었다. Centering 1.0 프로그램은 구간을 크게 정의할 때 반지름의 오차가 약간 있었으나, 구간을 작게 나눌수록 매우 근사치의 값을 제시하여주었다. 피칭과 퍼팅을 비교할 경우에 피칭의 반지름이 퍼팅보다 매우 작게 나타났으며, 퍼팅의 경우 중심의 위치는 인체 내에 있지 않고 최고 3m 외부에 위치하는 것으로 나타났다. Centering 1.0 프로그램은 회전운동에서 구한 데이터의 최소 3개만 입력하면 반지름 값을 알 수 있으며, 이것이 누적되면 회전운동 순간 중심점의 이동경로를 알 수 있다.

• Journal of Astronomy and Space Sciences
• /
• 제15권1호
• /
• pp.27-38
• /
• 1998

We discussed four different methods - the single, double and triple Gaussian fits, and the intensity weighted centroid fit - which extract rotation curves from several emis-sion lines(i.e. [OII], $H{\beta}$, [OIII], and $H{\alpha}$) of spiral galaxies. Spatial extents and the shapes of rotation curves derived through various methods applying to each emission lines of a sample galaxy UGC 11635 are all in a good agreement with one another. Linewidths of $H{\beta}$ and $H{\alpha}$ measure from rotation profiles are in a good agreement with $H{\alpha}$ linewidth of Courteau (1992). however, linewidths of [OII] seems to be much broader than $H{\alpha}$, and the profile of [OIII] does not follow the profile of $H{\alpha}$.

• 천문학회보
• /
• 제36권1호
• /
• pp.84.2-84.2
• /
• 2011

Astrophysical jets play important roles in many interesting astronomical phenomena, such as star formation, gamma-ray bursts, and active galactic nuclei. The jets are thought to be driven by rotating disks through magneto-centrifugal processes. However, quantitative understanding of the jet-driving mechanism has been difficult because examples showing rotation in both disk and jet are rare. One of the important quantities in the models of jet engine is the size of the jet-launching region. The bipolar jet of the NGC 1333 IRAS 4A2 protostar shows a lateral velocity gradient, which suggests that the SiO jet is rotating around its axis. The jet rotation is consistent with the rotation of the accretion disk. The disk-jet rotation kinematics suggests that the jet-launching region on the disk, or the outflow foot-ring, has a radius of about 2 AU, which supports the disk-wind models.

• Journal of Mechanical Science and Technology
• /
• 제16권4호
• /
• pp.485-491
• /
• 2002

The gyroscopes have been used as a suitable inertial instrument for the navigation guidance and attitude controls. The accuracy as very sensitive sensor is limited by the lock-in region (dead band) by the frequency coupling between two counter-propagating waves at low rotation rates. This frequency coupling gives no phase difference and an angular increment is not detected. This problem can be overcome by the mechanical dithering. The purpose of the mechanical dithering is to suppress the dead band, oscillate the monoblock about the rotation axis and add an external rotation rate. This paper presents the theoretical considerations of the mechanical performances of dither on the basis of the loading condition and angular characteristics due to the piezoelement deformation and the validity of theoretical equations are compared through FEM (Finite Element Method) simulations.