• 한국정밀공학회지
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• 제18권1호
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• pp.147-153
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• 2001

This paper proposes a shaker system design for acceleration test of gimbal. Main reason of shaker system design is to give acceleration to the gimbal, which is moving and tracking the target on the tracking test equipment. The shaker system is mounted on the tracking test equipment. It uses the scotch yoke mechanism to have the constant movement in return. The Scotch yoke mechanism changes the rotational movement of constant velocity to simple harmonic motion.

• 대한수학교육학회지:수학교육학연구
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• 제16권1호
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• pp.59-78
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• 2006

본 연구에서는 먼저, 미적분에서 수학과 물리를 연결한 학습-지도의 필요성을 논의하고, 이를 위한 교수-학습 자료를 개발하여 제시한다. 그 후, 교수-학습 자료 중 하나를 활용하여 질적 사례연구를 하여 등가속도 운동을 탐구하는 활동에서 평균속도와 순간속도 개념이 발달되는 과정을 분석하였다. 연구대상자들은 등가속도 운동을 탐구하는 물리적 실험 상황에서 평균속도, 순간속도, 가속도 개념을 배웠다. 이 과정에서 학생들은 순간속도가 시간과 이동거리의 이차함수 그래프 위의 한 점에서 접선의 기울기를 의미한다는 점과 시간과 속도의 관계그래프 아래의 넓이 변화율이 이동거리의 변화율을 의미한다는 점을 이해할 수 있었다.

• 한국군사과학기술학회지
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• 제16권1호
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• pp.89-94
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• 2013

Electro Otical Tracking System(EOTS) is required for a rapid movement as well as the stabilization of Line-Of-Sight(LOS). In order to achieve these two goals, this paper presents a position and velocity driving profile generation method from the constant acceleration and deceleration profile according to the current state, enabling a fast and smooth trajectory even if the target position changes during the movement of LOS. Simulation and experimental results reveal that the settling time could be reduced significantly by adopting the present position control scheme.

• Journal of Astronomy and Space Sciences
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• 제40권1호
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• pp.29-33
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• 2023

An unexplained acceleration on the order of 10^-8 cm s^-2, which is close to cH, where c is the speed of light and H is the Hubble constant, is detected in gravitationally bound systems of different scales, from the solar system to clusters of galaxies. We found that any test body located inside a fractal structure with fractal dimension D = 2 experiences acceleration of the same order and confirmed the previous work that photons propagating through this structure decrease the frequency owing to gravitational redshift. The acceleration can be directed against the movement of the test body. The fractal distribution of the matter should be at scales of at least hundreds of megaparsecs to a few gigaparsecs for the existence of this acceleration.

• PNF and Movement
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• 제5권1호
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• pp.49-56
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• 2007

Objectives : We find that the reaction force on the elbow joint during elbow flexion, extension with and without an object in the hand can be calculated the equations of motion that the sum of the torque and the sum of the force acting on the elbow joint must be zero and (moment of inertia x angular acceleration) and (mass x acceleration). Methods : we have calculated the equations of motion (${\Sigma}F=0$, ${\Sigma}{\tau}=0$, ${\Sigma}F=ma$, ${\Sigma}{\tau}=Ia$) to investigate the reaction force on the elbow joint during elbow flexion, extension by means of the simplified free-body technique for coplanar forces. Results : we found that the reaction force on the elbow joint during elbow flexion, extention as constant acceleration motion is more than constant velocity, static motion. Also, we found that the relation between during flexion and during extension like this ; $J_{flexion}$ < $J_{extension}$.

• 대한의용생체공학회:의공학회지
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• 제11권2호
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• pp.269-276
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• 1990

This study describes the battery functional test in order to explore vestibular oculomotor system. These tests are the following : a) acceleration test by using a pseudorandom stimulus. b) caloric test by considering both the constant temperature variation in the semicircular canals for a short time and the only head movement, to the fore and the back, for the ear ir- rigation, which gave us two types of stimulus (cold and warm) according to the only head position. c) optokinetic test by continuous constant velocity displacement of a large image fill- ing the entire subject's visual field. With relation to the clinical practices, some results of research programs which are at present in progress are presented.

• 한국인터넷방송통신학회논문지
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• 제19권1호
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• pp.133-138
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• 2019

스마트폰을 이용한 실내 항법 시스템은 대형 실내 시설에서 사용자의 위치 기반 서비스를 위해 매우 중요한 기반 기술이다. 이를 위해서 스마트폰에 내장된 가속도 센서와 자이로 센서를 이용하여 사용자의 이동 거리와 방향을 추정할 수 있다면 추가적인 외부 환경이 필요 없으므로 매우 유용한 기술이 된다. 본 논문은 일반적인 스마트폰에 Pedestrian Dead Reckoning(PDR) 기술과 칼만 필터를 적용하여, 사용자가 스마트폰을 가슴 앞에 잡고서 이동하면서 위치를 추적하는 실내에서의 항법 시스템 기술에 관한 것이다. 특히 회전 방향각을 추정하기 위하여 확장 칼만 필터가 설계되었고 실험적으로 일정속도로 보행하는 경우에 그 성능이 검증되었다.

• 제어로봇시스템학회논문지
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• 제3권2호
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• pp.132-138
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• 1997

Six different types of velocity profiles of trolley movement of a container crane are investigated for the minimal sway angle at the target trolley position. Three velocity patterns which include trapezoidal, stepped and notched-type velocity patterns are obtained assuming constant rope length. The notched type velocity pattern is shown to be derived from the time-optimal bang-bang control. The stepped type velocity pattern can be shown to be derived as bang-off bang control as well. Considering the damping effect due to hoist motion a double stage acceleration pattern is also analyzed. The main objective of the paper is to show how much time-reduction can be obtained among several velocity patterns appearing in the literature.

• 천문학회지
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• 제23권1호
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• pp.31-42
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• 1990

Fine structures of a quiescent prominence are studied by analyzing high resolution H alpha filtergrams and H alpha line spectra observed at the Hida Observatory of Kyoto University. We have found two kinds of downward motions in the prominence. One of them is a movement with a constant acceleration below the solar gravity(${\simeq}1/4g_s$) and the other with an uniform velocity(${\simeq}16Km/s$). The average life time and the size of prominence knots are estimated to be about 7 minutes and 4000Km, respectively. Spatial and brightness distribution of knots are also presented in this paper. With the analytical solutions derived from magnetostatic equilibrium in the prominence, we have examined the filamentary structure based on the Kippenhahn-Schluter model. Sag angles of the magnetic fields supporting the prominence matter are predicted from the observed density profile.

• 대한기계학회논문집A
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• 제21권6호
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• pp.907-917
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• 1997

The purpose of this study is to design an anti-sway motion for industrial overhead cranes which transport objects on a horizontal plane by adjusting movements of a trolley motor and a girder motor. The movement of a hoist motor has not been considered at this time since its role was assumed to move objects only vertically, therefore, not to affect the swing motion of objects. The dynamic behavior of the swing motion shows nonlinear characteristics, which makes the design of anti-sway motion controller difficult. First of all, the nonlinear state equation for the motion of industrial overhead cranes has been derived. Then they have been linearized about normal operating states determined by the dynamic characteristics of motor motion-acceleration, constant speed, and deceleration, and deceleration, during transportation. The partial state feedback control algorithm based on this linearized state equation has been developed on order to suppress the swing motion. The simulation results have demonstrated satisfactory performance of the proposed controller.