• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.3
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• pp.63-70
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• 2010

We are able to find many materials of pendulum dynamic/analysis using linearized model. Usually, analysis of pendulum is to calculate for velocity, period and angle by linearized model on Newton's law. In this paper, analyzed periodical movement of pendulum using nonlinear load model. That is, analyzed load value according to location of moving pendulum at real time. And for the shake of maneuver for pendulum's location, found load control value and compared result of linearized mode with nonlinear model. The result makes know that it is possibility of nonlinear load control model to apply to various model of movement object including flight object, pendulum and etc.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.130-131
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• 2017

부유체의 횡동요는 부유체의 안정성을 헤칠 뿐 아니라 승조원의 피로를 누적시키고, 기자재의 안정적인 운용과 수명에도 영향을 미친다. 본 연구에서는 점성감쇠 안티롤링진자를 이용하여 부유체의 횡동요를 줄이는 방법을 제안하고, 안티롤링진자의 효용성을 보인다. 약 1m, 7.7kg의 모형선에 32g, 40g, 50g의 안티롤링진자를 탑재하여 16%~23.5%의 롤링 저감 효과를 얻을 수 있었다.

• Journal of Navigation and Port Research
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• v.40 no.6
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• pp.361-368
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• 2016

A ship's rolling motion can make crew and passengers sick and/or apply forces to the structure that cause damage.. Therefore bilge keels are equipped in most ships for anti-rolling. In special cases, anti-rolling tanks (ARTs), fin stabilizers, or gyroscopes can be installed. However, ARTs require a large area to install, and fin stabilizers and gyroscopes are costly to install and expensive to operate. This paper suggests a Anti-rolling pendulum (ARP) to reduce roll motion. ARPs acts like ARTs. However, the ARP has a circular shaped guidance arc instead of the string or wire of a simple pendulum. The device suggested has about 1/ 8 the weight and 1/ 6 the volume of a ART and is more effective. This study derives the nonlinear and linear differential equations of system motion.

• Journal of Science Education
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• v.32 no.1
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• pp.1-18
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• 2008

We investigated 8th grade science textbooks and their instructor's manuals treating the ideal condition for isochronism of a simple pendulum. The isochronism, i.e. the period is independent of amplitude, is satisfied only if the amplitude is very small. This is so called "ideal condition" for isochronism of a simple pendulum. Most textbooks and instructor's manuals are found not to state this ideal condition properly, which often leads to the deviation between experimental data and theoretical calculation. This difference between theoretical and experimental results makes students to create a sense of alienation from the real world and eventually keeps them away from physics. We thus study the cycloidal pendulum as an alternative method to test the isochronism regardless of amplitude and discuss the practical utility of it in class.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.252-255
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• 2001

본 논문은 단일 도립 진자 계통(single pendulum systems)의 경우 계통의 에너지를 슬라이딩 평면을 구성하는데 이용한 슬라이딩 모드 제어기를 설계하고 기존의 에너지 기반 제어 기법의 결과와 비교, 그 성능에서 우위에 있음을 보인다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2016.05a
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• pp.106-107
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• 2016

Rolling motion of floating body might upset the body, make crews and passengers exhausted and/or apply forces to the structure to cause damage. Therefore for almost ships bilge keels are equipped, in special case fin stabilizer or gyroscope may be installed. This paper suggests the Anti-rolling pendulum to reduce roll motion to act the similar role with anti-rolling tank. The device suggested has more effective than the anti-rolling tank with 1/6 volume of the tank.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.2
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• pp.13-22
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• 1998

This paper summarizes a study on the application of the friction pendulum system in bridge seismic isolation. Shaking table tests have been carried out on a model structure isolated with F.P.S and the obtained structural responses are compared to those of non-isolated. It can be concluded the F.P.S increases the earthquake resistance capacity of the isolated structure. It is also found that the stiffness of bearing, being controlled by the radius of curvature of the spherical sliding interface, is unaffected by the amplitude of the input excitation. Furthermore, the coefficient of sliding friction is velocity dependent so that in weak excitation the sliding velocity is low and, accordingly, the mobilized friction force is less than the one mobilized in strong excitation. Also, the frictional properties of the bearings remain markedly stable after extensive testing, and the permanent displacements are small and not cumulative in successive earthquakes.

• Journal of Navigation and Port Research
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• v.41 no.6
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• pp.365-372
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• 2017

The rolling motion of a floating body makes crews and passengers exhausted and/or applies forces to the structure to cause damage; it might even upset the body. Therefore, almost all ships are equipped with bilge keels for anti-rolling; in special cases, an anti-rolling tank(ART) or fin stabilizer or gyroscope could be installed. But an ART requires a large capacity to install it, and a fin stabilizer and gyroscope need great costs to install and also many expenses to operate. The authors suggest the use of an anti-rolling pendulum(ARP), and they showed that the ARP is effective to reduce rolling by experiments and via a Runge-Kutta analysis. This paper introduces the linearized 2 degrees of freedom with a viscous damping system for a ship equipped with ARP; it also shows the validation of the linearized analysis for the ship's roll motion. The paper proposes an optimum ARP on the basis of the justified model. The case of the 7.7kg model with ship 20g ARP of a mass ratio of 0.26%, is the most effective for reducing roll motion. The paper shows the ARPs with various mass ratios are effective for reducing the roll motion of a ship by free decaying roll experiments.

• Proceedings of the Korean Fiber Society Conference
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• 1995.10a
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• pp.36-36
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• 1995

• Journal of The Korean Association For Science Education
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• v.25 no.5
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• pp.583-594
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• 2005

This study examined 8th-graders' conceptions of force on a simple pendulum and investigated cognitive conflict and conceptual change through kinesthetic experience in swing. Participants of this study were guided to anticipate the direction of total force acting on a pendulum at three critical positions and observed it through swing experience. Having completed this, students read an article explaining the results they observed. Most of them considered gravity, tension, and motion-force to be the real forces acting on a pendulum in pre-test. Though they were interested in the activity and conceded their expectations to be different from observed results, the degrees of their cognitive conflict were not significantly high. In summation, 'interest' was the highest and 'anxiety' was the lowest. Most of the students memorized the direction of forces on a swing, but few could explain the reason behind the occurrence in an immediate post-test and delayed post-test.