• 한국전문물리치료학회지
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• 제8권3호
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• pp.43-52
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• 2001

This study was designed to determine the effect of ankle taping and short period of walking on the treadmill on the range of motion (ROM) and proprioception at the ankle joint. Twenty healthy male subjects (mean age=24.2 yr) participated in this study. Goniometry and videotape replaying method were used to measure the ankle ROM. Passive sagittal and frontal plane motions were measured. The difference in degree between the stimulus point and the reproduced point was defined as an angular error. The measurements were performed at four different phases: pre-taping (PRT), post-taping immediately (POT), post-5 minute walking with taping (P5M), and post-10 minute walking with taping (P10M). The ankle of dominant limb was taped by a certified athletic trainer using a closed basket weave technique. Participants walked on the treadmill at 2.5 mph. The results showed that the mean of the sagittal plane motion at PRT, POT, P5M, and P10M was 53.0, 30.5, 36.2, and 40.2 degrees, respectively. The frontal plane motion at PRT, POT, P5M, and P10M was 33.6, 13.9, 15.7, and 18.6 degrees, respectively. The angular error at PRT, POT, P5M, and P10M was 5.5, 1.6, 1.8, and 1.9 degrees, respectively. After 10 minutes of walking, the sagittal plane motion and frontal plane motion was increased by 9.7 and 4.7 degrees compared with POT, respectively. The proprioception was significantly improved after the application of ankle taping. Both the restriction of frontal plane motion and proprioception improvement at the ankle joint may contribute to ankle stability during walking.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.312.1-312
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• 2002

In this paper, we analyse and present mechanical dynamic characteristics of a micro-machined vibrating silicon ring gyroscope which can measure rates of turn about three orthogonal axes. The ring gyroscope has a ring connected to the gyroscope main body by support-ligaments which are arranged with cyclic symmetry. The natural modes of its vibration can be distinguished into the in-plane motion and the out-of-plane motion which are coupled by the gyro-effect due to the rotation of the gyroscope main body. (omitted)

• 호남수학학술지
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• 제40권1호
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• pp.187-198
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• 2018

In this paper, we study the instantaneous geometric properties of motion of rigid bodies in the Lorentzian plane. For this purpose we define Lorentzian form of Bottemas instantaneous invariants. In these regards, we obtain the necessary and sufficient condition of a Lorentzian plane to be at Cardan position with respect to these invariants.

• 대한기계학회논문집
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• 제7권2호
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• pp.175-185
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• 1983

When a circular cylinder near the plane fluid-interface of different viscosities is in parallel and normal motion, solutions of the Oseen equation are obtained. Classical image method with Faxen's integral form is used to satisfy the boundary conditions on the plane interface. Coefficients of drag and lift increase as a cylinder approaches to the interface. But drag-coefficients of parallel motions with viscosity-ratio less than unity are decreased slightly. They show monotonic increase with Reynolds number in case of parallel motion, but minimum values of drag coefficients in normal motion are appeared. On the other hand Stokes' solution are obtained by taking limits of low Reynolds number except the case of parallel motion with viscosity-ratio not equal to infinity.

• Journal of Acupuncture Research
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• 제30권4호
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• pp.25-33
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• 2013

Objectives : To assess the test-retest reliability and the intratest repeatability in measuring the cervical range of motion of healthy subjects with wireless microelectromechanical system inertial measurement unit(MEMS-IMU) system and to discuss the feasibility of this system in the clinical setting to evaluate the cervical spine musculoskeletal. Methods : 12 healthy people who were evaluated as no- or mild-disability with neck disability index were participated. Their cervical motion were measured with IMU twice in consecutive two days for the test-retest reliability study. Intratest repeatability was calculated in the two tests separately. The calculated intraclass correlation coefficients(ICC) were discussed and compared with the those of the previous studies. Results : Cervical range of motion data were acquired and statistically processed: left rotation($61.64^{\circ}$), right rotation($65.12^{\circ}$), extension($61.98^{\circ}$), flexion($52.81^{\circ}$), left bending($39.31^{\circ}$), right bending($41.08^{\circ}$). ICCs were 0.77~0.98(intratest repeatability) and 0.74~0.93 (test-retest reliability) in the primary motion. In the coupling motion, intratest repeatability ICCs were 0.93~ 0.99(transverse primary plane), 0.88~0.97(saggital primay plane), and 0.77~0.93(coronal primary plane). Test-retest reliability of coupling motion were 0.90~0.97(transverse primary plane), 0.00~0.72(saggital primary plane), and 0.04~0.76(coronal primary plane). Conclusions : Several types of range-of-motion devices are now on use in many fields including medicine, but the practicality of the devices in clinical use is questionable for the convenient and economical aspects. In this study, we presented the reliability of cervical range of motion test with the developed wireless MEMS-IMU system and discussed its potential utility in clinical use.

• 한국과학교육학회지
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• 제33권1호
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• pp.193-207
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• 2013

이 연구는 지구와 달 표면에서 물체의 운동에 대한일반 중학생들과 과학영재학생들의 개념을 조사하였다. 연구 대상은 일반 중학교 중학생 1학년 61명, 2학년 51명, 3학년 51명 총 163명과 대학부속 과학영재교육원 중등 과학영재학생 32명으로 하였다. 연구 내용은 지구와 달 표면에서 연직, 경사면, 수평면에 따른 물체의 운동에 대한 개념으로 하였다. 각각 지구와 달 표면에서 크기는 같고 질량이 다른 두 물체를 동시에 놓거나, 같은 속력으로 위쪽으로 던지거나, 수평면에서 굴렸을 때 '어느 것이 먼저 도착하는가?'를 조사하였다. 지구와 달 동시 상황에서는 같은 물체를 지구와 달 표면에서 동시에 놓거나, 던지거나, 굴렸을 때 '어느 장소에 먼저 도착하는가?'를 조사하였다. 연구결과 과학영재학생들이 일반 중학생들 보다 지구 표면에서 연직, 경사면, 수평면의 모든 조건에서 물체의 운동에 대한 개념에 유의미한 차이가 있었고, 달 표면에서 연직 위 방향에서 물체의 운동에 대한 개념에 유의미한 차이가 있었다. 지구와 달 표면 동시 상황에서는 연직 아래 방향에서 물체의 운동에 대한 개념에 유의미한 차이는 없었고, 연직 위 방향, 경사면, 수평면에서 물체의 운동에 대한 개념에 유의미한 차이가 있었다. 연구 결과를 통해서 얻은 결론은 첫째, 지구와 달 표면에서 물체의 운동에 대한 설명을 할 때 진공에 대한 의미와 중력의 크기에 대한 학습이 먼저 이루어져야 한다. 둘째, 중학생들에게 다양한 상황과 조건에서 물체의 운동을 통합적으로 이해하도록 지도해야한다. 셋째, 중학생들은 상황을'동일시'하려는 사고 경향이 있다. 마지막으로 힘과 물체의 운동은 물리 영역에서 매우 중요한 단원이며, 교사가 물체의 운동을 설명할 때 위 결과들을 유념해서 가르쳐야 한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2248-2253
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• 2005

Although the progress in bipedal walking is impressive in recent years, biped robots still require very high torque and can walk only for a short time interval with their internal batteries. Therefore, further research needs to be carried out to enhance walking efficiency of these robots. In order to achieve this goal, we attempt to imitate human walking with pelvis and waist joint rotations in the frontal plane. In order to investigate the effect of the pelvis and waist joint rotations in the frontal plane motion, we study the frontal plane model with a triangular structure made up of a waist joint and two hip joints. Through simulation, we show that the pelvis rotation can reduce the maximum torque and the control effort, and the waist joint rotation can reduce the trunk sway caused by the pelvis rotation. The combination of these two rotations makes the bipedal walking in the frontal plane more efficient.

• 한국운동역학회지
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• 제25권3호
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• pp.311-322
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• 2015

Objective : The purpose of this study was to investigate the effects of landing height and knee joint muscle fatigue on the movement of the lower extremity during cutting after landing. Method : Subjects included 29 adults (age: $20.83{\pm}1.56years$, height: $172.42{\pm}9.51cm$, weight: $65.07{\pm}10.18kg$). The subjects were asked to stand on their dominant lower limb on jump stands that were 30 and 40 cm in height and jump from each stand to land with the dominant lower limb on a force plate making a side step cutting move at a $45^{\circ}$ angle with the non-dominant lower limb. The fatigue level at 30% of the knee extension peak torque using an isokinetic dynamometer. Results : The results showed that the difference of landing height increased maximum range of motion and angular velocity of hip, knee, and ankle joints in the sagittal plane, and in the angular velocity of motion of the hip joint in the sagittal plane. The maximum range of motion of the knee joint in the sagittal plane and the frontal plane decreased on landing from both heights after the fatigue exercise. The angular velocity of the hip joint in the sagittal plane, and the maximum range of motion of the hip joint in the transverse plane decreased for both landing heights after the fatigue exercise. The angular velocity of the hip joint in the frontal plane decreased for the 30 cm landing height after the fatigue exercise. On the other hand, the angular velocity and maximum range of motion of the ankle joint in the sagittal plane for both landing heights, and the angular velocity and maximum range of motion of the ankle joint in the frontal plane increased on landing from the 40 cm height after the fatigue exercise. Conclusion : Different landing heights of 30 and 40 cm and 30% fatigue of peak torque of knee extensor found a forefoot and stiff landing strategy, when cutting after landing. These results might be due to decline in the shock absorption capability of the knee joint and the movement capability related to cutting while increasing the contribution of the ankle joint, which may cause increased ankle joint injuries.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.843-855
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• 2020

X-plane submarines show better maneuverability as they have much longer span of control plane than that of cross plane submarines. In this study, captive model tests were conducted to evaluate the maneuverability of an X-plane submarine using Computational Fluid Dynamics (CFD) and a mathematical maneuvering model. For CFD analysis, SNUFOAM, CFD software specialized in naval hydrodynamics based on the open-source toolkit, OpenFOAM, was applied. A generic submarine Joubert BB2 was selected as a test model, which was modified by Maritime Research Institute Netherlands (MARIN). Captive model tests including propeller open water, resistance, self-propulsion, static drift, horizontal planar motion mechanism and vertical planar motion mechanism tests were carried out to obtain maneuvering coefficients of the submarine. Maneuvering simulations for turning circle tests were performed using the maneuvering coefficients obtained from the captive model tests. The simulated trajectory showed good agreement with that of free running model tests. From the results, it was proved that CFD simulations can be applicable to obtain reliable maneuvering coefficients for X-plane submarines.

• 한국소음진동공학회논문집
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• 제15권10호
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• pp.1186-1194
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• 2005

In this paper, we have systematically formulated the equations concerned to the in-plane and out-of-plane motions and deformations of a thick circular beam by using the kinetic and strain energies in order to analyse natural frequencies of a thick ring. The effects of variation of radius of curvature across the cross-section and also the effects of bending shear, extension and twist are considered. The equations of motion for natural vibration analysis of a ring are obtained utilizing the cyclic symmetry of vibration modes of the ring. The frequencies calculated using thick ring model and thin ring model are compared and discussed with the ones obtained from finite element analysis using the method of cyclic symmetry with 20-node hexahedral solid elements for rings with the different ratio of radial thickness to mean radius.