• Journal of Power Electronics
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• v.18 no.4
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• pp.1190-1200
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• 2018

A current sourced bi-directional wireless power transfer (WPT) system is proposed to solve the problems that exist in the bi-directional WPT for vehicle-to-grid (V2G) systems. These problems include the fact that these systems are not safe enough, the output power is limited and the control methods are complicated. Firstly, the proposed system adopts two different compensation and control methods on both the primary and secondary sides. Secondly, based on an AC impedance analysis, the working principle is analyzed and the parameter configuration method with frequency stability is given. In order to output a constant voltage, a bi-directional DC/DC circuit and a controllable rectifier bridge are adopted, which are based on the "constant primary current, constant secondary voltage" control strategy. Finally, the effectiveness and feasibility of the proposed methods are verified by experimental results.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.405-408
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• 2007

Vestibular hair cells, the sensory receptors of vestibular organs, selectively amplify miniscule stimuli to attain high sensitivity. Such selective amplification results in compressive nonlinear sensitivity, which plays an important role in expanding dynamic range while ensuring robustness of the system. In this study, negative stiffness mechanism, a mechanism responsible for the selective amplification by vestibular hair cells, is applied to a simple mechanical system consisting of an array of inverted pendulums. The structure and working principle of the system have been inspired by gating spring hypothesis proposing that opening and closing of transduction channels contributes to the global stiffness of vestibular hair bundle. Parameter study was carried out to analyze the effect of each parameter on the compressive nonlinearity of suggested model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.677-682
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• 2007

Recently, a precision stage is widely used in the fields of the nano technology. In this paper, the precision stage which consists of linear motor, vision system, light source system and controller, is designed and developed for nano imprint machine. Stiffness design considering resonance frequency is important for the precision stage. A virtual machine simulation is useful for machine development the early design stage. Kinematic and dynamic simulations of XYZ stage are performed. To consider the resonance frequency and vibration effects flexible multibody dynamics are utilized with FE modeling of the structural components.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.9
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• pp.716-723
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• 2014

Vibration measurement using image processing is a fully non-contact measurement method and has many application fields. The resolution of vibration data measured by image processing depends on the camera performance and is lower than that measured by accelerometers. This work discusses the method to increase resolution of vibration signal measured by image processing based on the image mosaic technique with a high-power lens. The working principle of resolution enhancement was explained theoretically and verified by several experiments. It was shown that the proposed method can measure vibrations of relatively large scale structures with increased resolutions.

• Journal of the Korean Professional Engineers Association
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• v.25 no.4
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• pp.52-58
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• 1992

In korea, since November 1982 these two small group activity (QC circle convension and Factory Saemaul activity small group convension) has been united, many problems have been disclosed that are aganist the basic principle more or less. Worker's small group within their working place to improve the surroundings creatively. In practice, however, many group are so typical and impetuous of the material effect that it is worried to be inclined to outform rather than contents. Effective small group activities are presumed to be successful only with labour management cooperation on the basis of human-orient management philosophy. The small group activities are also prevalent in service sector. More derivative methods have been developed and more members are willingly participation in training programs. The small group which is basically a horizontal organization unit, promptes communication within the whole organization, In consideration of social circumstances and traditions, the flexible model of the small group activities suitable to the corporate environment, will contribute to industrial development.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.114-121
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• 2002

This paper describes the control system of the toroidal traction driver continuously variable-speed transmission(CVT) fur a tractor. The instrumentation system, the hydraulic power control system and the principle control scheme were introduced. Experimental tests in the bench and the tractor were conducted to validate the performance of the CVT utilizing the proposed controller. The speed of the vehicle was continuously changed to follow the speed set by driver under various operating conditions. Given the reduction ratio of the variator from 2.0 to 1.0, the settling time was about just 0.52 seconds which was satisfactory value for working with the tractor. It was also proved that the tractor could work with continuously variable speed under heavy load disturbances.

• Journal of the Korean Society of Safety
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• v.12 no.3
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• pp.23-29
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• 1997

In the control of crane system, the traversing time of the trolley must be reduced as much as possible and the swing must be stopped at the end point. To design the minimum time control system, Pontryagim maximum principle is applied. In order to implement the control algorithm, the dynamic equation is linearlized at an equilibrium point, so that the linear time invariant state equation can be obtained. The overall performance of the closed loop system is evaluated by means of computer simulations and practical experiments in a broad range of working conditions. The effectiveness is proved through the experimental results for the anti-sway control of the load and the position control of trolly. It is expected that the proposed system will make an important contribution to the industrial fields.

• Korean Journal of Psychosomatic Medicine
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• v.1 no.1
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• pp.3-13
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• 1993

Since the onset of modern psychosomatic medicine decades ago. it has made significant at contribution to general medicine in terms of understanding the patient as a whole person suffering from an illness rather than as a disease per se. However, initial expectation of delineating specific psychogenesis and developing specific treatment modality has not been fulfilled. Consequently, it has raised substantial concern about the continuing utility of psychosomatic medicine in modem medicine. The author attempted to review critically the evolution of psychosomatic medicine from the perspective of the present and to make projections into the near future. It is concluded that psychosomatic medicine in the future will continue to contribute to development of modem medicine not only as the scientific principle but also as the practical methodology, working as creative interface among disciplines and fusing ideas from rapidly developing molecular biology and neuroscience with psychosomatic concepts. Finally, suggestions for further developing psychosomatic medicine in Korea are made.

• Journal of Power Electronics
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• v.14 no.6
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• pp.1217-1223
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• 2014

A novel half load-cycle worked dual input single output (DISO) DC/AC inverter is presented. The basic circuit consists of a dual buck regulator, which works in continuous current mode. The working principle of DISO DC/AC inverter has been used. The control method applied for half load-cycle worked DISO DC/AC inverter has been studied. The control effects of the open-loop proportional control and closed-loop proportional-integral control are compared by using PSIM software. The parameters are adopted in the realistic simulation and experiment test. Moreover, the waveforms, such as voltage of modulation reference signal and output voltage, were given. The simulation and experiment results proved that the half load-cycle worked DISO DC/AC inverter could achieve good performance, gain a line frequency of 50 Hz, and verify the correctness of theoretical analysis.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.10a
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• pp.150-153
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• 2006

Micro vibration isolation, typically originated from ground, is always a prime concern for the nano-measurement instruments such as Atomic Force Microscopes. A four mount active vibration isolation system is proposed in this paper. Modeling and control of such a four mount system as analyzed. Combined active-passive isolation principle is used for vibration isolation by mounting the instrument on a passively damped isolation system made of Elastomer along with the active stage in parallel that consists of very soft actuation system, the Voice Coil Motor. The active stage works in combination with the passive stage for working as a very low frequency vibration attenuator.