• Communications of Mathematical Education
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• v.22 no.4
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• pp.545-556
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• 2008

In this paper we study Gergonne's point and its adjoint points of triangle using the principle of the lever. We prove existence of Gergonne's point and its adjoint points, suggest new proof method of a equality related with Gergonne's point. We find new equalities related with adjoint points of Gergonne's points, and prove these using the principle of the lever.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.5 s.170
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• pp.121-129
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• 2005

Lever mechanisms are usually employed to enlarge output displacements in precision stages. In this study, theoretical analysis is done for a precision stage employing a lever and flexure hinges, including bending effect. This study presented relations between design parameters and magnification ratio. This study presents optimal values for the parameters to achieve a longer stage displacement. The analysis is verified by finite element analysis. It is found that adjusting stiffnesses can increase the travel range significantly.

• Communications of Mathematical Education
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• v.24 no.1
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• pp.159-175
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• 2010

In this paper we make a new problem solving model using the principle of the lever. Using the model we solved many word problems related with consistency. We suggest new problem solving method using the lever model and describe some characteristics of the method.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.09a
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• pp.27-30
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• 2005

A nanoelectromechanical (NEM) switching device based on carbon nanotube (CNT) was investigated using atomistic simulations. The model schematics for a CNT based three-terminal NEM switching device fabrication were presented. for the CNT-based three-terminal NEM switch, the interactions between the CNT-lever and the drain electrode or the substrate were very important. When the electrostatic force applied to the CNT-lever was the critical point, the CNT-lever was rapidly bent because of the attractive foroe between the CNT-lever and the drain. The energy curves for the pull-in and the pull-out processes showed the hysteresis loop that was induced by the adhesion of the CNT on the copper, which was the interatomic interaction between the CNT and the copper.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.12
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• pp.1648-1656
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• 2018

The configuration of redundant inertial sensors are very important when considering navigation performance and fault detection and isolation (FDI) performance. By constructing a redundant sensor system using multiple inertial sensors, it is possible to improve the navigation performance and fault detection and isolation performance, which are highly related to the sensor configuration and allocation. In order to deploy multiple MEMS inertial measurement units effectively, a configuration and allocation methods considering navigation performance, fault detection and isolation performance, and lever arm effect in one plane are presented, and the performance is analyzed through simulation in this research. From the results, it is confirmed that the proposed configuration and allocation method can improve navigation, FDI, and lever arm effect rejection performances more effectively by more than 70%.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.10
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• pp.941-946
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• 2013

In this paper, an enhanced method for attitude determination is proposed for systems using an IMU (Inertial Measurement Unit). In attitude determination with IMU, it is generally assumed that the IMU can be located in the center of gravity on the vehicle. If the IMU is not located in the center of gravity, the accelerometers of the IMU are disturbed from additive accelerations such as centripetal acceleration and tangential acceleration. Additive accelerations are derived from the lever arm which is the distance between the center of gravity and the position of the IMU. The performance of estimation errors can be maintained in system with a non-zero lever arm, if the lever arm is estimated to remove the additive accelerations from the accelerometer's measurements. In this paper, an estimation using Kalman filter is proposed to include the lever arm in the state variables of the state space equation. For the Kalman filter, the process model and the measurement model for attitude determination are made up by using quaternion. In order to evaluate the proposed algorithm, both of the simulations and the experiments are performed for the simplified scenario of motion.

• Korean Journal of Childcare and Education
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• v.9 no.2
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• pp.117-141
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• 2013

The purpose of this study is to investigate the young children's 'more means more' bias and knowledge change process regarding a lever phenomenon, especially the relationship between the weight of an object and the strength of force and between the length of a lever and the strength of force. Subjects, who were presented with the tasks, were eight young children 5 years of age. Major findings were as followings. First, most of the subjects have a 'more means more' bias about the relationship between the weight of an object and the strength of force and between the length of a lever and the strength of force regarding a lever phenomenon. This meant that young children have similar concepts about a lever phenomenon regardless of whether it is right or wrong physically. Second, young children tried to make sure of their knowledge during experiments. They chose the evidence which confirmed their knowledge. But they tried to change their knowledge, when the evidence presented did not correspond to their knowledge. These findings contribute to understanding young children's 'more means more' bias and knowledge change process about a lever phenomenon and can be used in preschool science education programs and curriculums.

• 전기의세계
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• v.24 no.4
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• pp.77-79
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• 1975

It is suggested in this paper that an elastic lever may be used as a mechanical network element having mutual spring. The cantilever spring is examined as an example of the elastic lever, and the spring compliances, compatibility condition and design procedure of the cantilever spring are briefly investigated.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.669-670
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• 2008

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.1965-1971
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• 2010

A ship propulsion thruster platform which is used by safety sailing takes charge of remote control of a main engine in ship. This system not only guarantees safety and reliable flight sailing but also require remote control technology of a ship. Accordingly, in this paper it deals with a telegraph lever control unit system which is a part of propulsion thruster system as localization technology. Also it makes sure of knowledge and core technology through analysis and designing and developing a telegraph lever control unit system. Moreover, it is sure of acquisition of base technology for integration of a ship propulsion thruster platform.