• Journal of the Korean Society of Earth Science Education
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• v.13 no.1
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• pp.29-39
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• 2020

In this study, to find out the learning effects and difficulties of role play activities to learn the earth's rotation and the sun's apparent motion, the degree of concept understanding through role play activities, difficulties arising from activities collected by interview, and eye movement during activities are analyzed. 22 fifth graders participated in this study and collected and analyzed experimental behaviors, post-interviews, and eye movement data during the role play of the students. The study found that students could explain the rotation and direction of the Earth through role play activities, but it was difficult to explain the apparent motion of the sun. Since it is difficult to perceive the sun's apparent motion through role play activities, the learning effect of the earth rotation role play activity is low.

• Proceedings of the Korean Information Science Society Conference
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• 2001.10b
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• pp.520-522
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• 2001

본 논문에서는 동작 표본을 이용하여 내재하는 동작 특성을 추정하고, 이를 동작 변환에 적용하는 새로운 동작 변환 알고리즘을 제안한다. 기존의 역 운동학에 기반한 동작 변환 알고리즘은 우선 앤드 이펙터 (end effector)의 궤적 차이를 줄이도록 한 후, 자세 공간에서 동작간의 거리를 최소화하는 방향으로 자세를 변환시켰다. 그러나 동작간의 거리에 대한 정의가 명확하지 않고, 이렇게 생성된 동작이 동작 주체가 취할 수 있는 자세라는 보장이 없기 때문에 실존 가능성이 낮은 부자연스러운 동작이 생성될 수 있다. 본 논문에서 제안하는 방법은 역 운동학 기반의 실존 가능성이 높은 자연스러운 동작 생성을 위해 동작 주체의 동작 표본을 고려한 확률분포를 이용한다. 제시된 알고리즘을 통한 동작 변환은 실존 가능성이 높은 자연스러운 동작을 생성할 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.4
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• pp.295-300
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• 1990

Inverse kinematic problem is a crucial point for robot manipulator control. In this paper, to implement the Jacobian control technique we used the Hopfield, Tank's neural network. The states of neurons represent joint velocities, and the connection weights are determined from the current value of the Jacobian matirx. The network energy function is constructed so that its minimum corresponds to the minimum least square error. At each sampling time, connection weights and neuron states are updated according to current joint positon. Inverse kinematic solution to the planar redundant manipulator is solved by computer simulation.

• Review of Korea Contents Association
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• v.13 no.3
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• pp.18-22
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• 2015

• Journal of Navigation and Port Research
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• v.34 no.10
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• pp.735-740
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• 2010

This paper focuses on the effects of hydrodynamic forces between overtaking and overtaken vessels moving under the influences of external forces, such as strong wind and current in shallow water, in which condition the ship handling may become very complex. The purpose of this paper is to develop a guideline for safe conducting distance between two ships according to the velocity and the significance of external disturbances.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.11
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• pp.990-998
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• 2007

Adaptive output feedback control technique using Neural Networks(NN) is proposed for uncertain nonlinear Multi-Input Multi-Output(MIMO) systems. Modified Dynamic Inversion Model(MDIM) is introduced to decouple uncertain nonlinearities from inversion-based control input. MDIM consists of approximated dynamic inversion model and inversion model error. One NN is applied to compensate the MDIM of the system. The output of the NN augments the tracking controller which is based upon a filtered error approximation with online weight adaptation laws which are derived from Lyapunov's direct method to guarantee tracking performance and ultimate boundedness. Several numerical results are illustrated in the simulation of Van der Pol system and unmanned helicopter with model uncertainties.

• Journal of the KSME
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• v.28 no.2
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• pp.138-145
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• 1988

본 글에서는 로봇의 운동학적 및 동력학적 문제를 풀기 위한 기본적 이론과 그 적용례를 들었다. 운동학적 고찰은 로봇 링크의 위치와 방향을 설정하기 위한 동차변환에 근거하여 이루어졌고, 기준좌표계와 조인트 좌표계사이의 정변환과 역변환이 정운동학과 역운동학적 과정에서 고찰되 었다. 동력학적 과정에서는 로봇은 능동기구로 간주하여 운동방정식이 유도되었으며 이 유도 과정에서 운동학적 분석결과가 어떻게 사용되는가를 살펴보았다. 한편 유도된 운동방정식이 어떻게 활용되는가를 정동력학과 역동력학적 과정을 통하여 살펴보았으며 이러한 과정들은 로 봇의 설계, 모델링(simulation), 제어 등 연구에 기초이론으로 사용됨을 적용례를 통하여 보였고 일반적으로 정운동학, 역운동학, 역동력학, 정동력학의 순으로 전개됨이 합리적이라는 것을 인 지하였다.

• The Magazine of the IEIE
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• v.42 no.12
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• pp.49-54
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• 2015

• Journal of the Korean Society of School Health
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• v.8 no.1
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• pp.17-18
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• 1995

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.4
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• pp.276-283
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• 2017

This paper presents position control of multicopter using nonlinear dynamic model inversion in singular perturbation. Multicopter dynamics are developed and separated into the fast time-scale variables, related with the inner-loop design, and the slow time-scale variables, related with the outer-loop design. The final design is evaluated in 6-DOF simulation. The results show accurate position tracking performance.