• Proceedings of the KSR Conference
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• 2008.06a
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• pp.691-706
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• 2008

ATP(Automatic Train Protection) system in railway signaling system is the important one grasping the position and velocity of a train. The wayside transmitter of ATP system is installed between rails. In concrete slab track, the signal current using wayside transmitter of ATP system is influenced by reinforcing bars. The magnetic coupling between reinforcing bars and wayside transmitter of ATP system as a filter makes an input current distorted. So, it makes an alternating current signal with a desirable size not transmit to on-board system of a train. Way to decrease the distortion of an input current signal frequency is to avoid maximum induction current frequency. And the induction phenomenon between reinforcing bars insulated and wayside transmitter of ATP system does not occur. In this paper, we represent the model about wayside transmitter of ATP system and reinforcing bars on the concrete slab tracks, and calculated the parameters demanded for the model. Also, we demonstrated it through the Maxwell program. Furthermore, we calculated impedance on wayside transmitter used in KVB system and ERTMS/ETCS system which are a kind of ATP system, frequency response of induction current, using the Matlab, and demonstrated the validity of it, using the PSpice program.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1649-1654
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• 2009

Induction motors widely use in industry because structure is simple and hard and cost is generally cheap and they are easy to control. In recently, because of saving steel, ventilation and benefit of frame fixing, rectangular core type induction motors use in industry more and more. This paper presents current characteristic according to stator core cutting degree in three-phase induction motor (IM) with rectangular stator core. According to stator cutting degree, magnetic saturation and paths of flux are changed. Because of these situations, phase currents are unbalance and are produced harmonic components and they cause decrease of efficiency. We analyze each $10^{\circ}$ from $0^{\circ}$ to $30^{\circ}$ using 2-D finite element analysis (FEA). Optimal stator cutting core degree selection supplies stable currents and efficiency improvement. In this paper, loss separation test was executed by IEEE Std. 112-98 Method B and we compare with the result of loss separation by Simulation using FEM and by Experiment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.1
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• pp.80-85
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• 2003

Recently, induction heating cooker(IH-Cooker) is very interested for high efficiency, the quickness of heating time and the convenient regulation of heating spot. In this paper, we proposed the magneto-thermal analysis of an induction heating cooker(IH-Cooker) as an efficient design, and analyzed the magnetic fold intensity inside the axisymmetric shaped cooker using three-dimensional axisymmetric finite element method(Flux2D) and the effectual heat source was obtained by ohmic losses from eddy currents induced in the cooker. Also, we presented the temperature characteristics of the IH-Cooker according to input frequency and relative permeability in stainless parts and in aluminum parts.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.12 no.4
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• pp.29-36
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• 1998

In this paper, two-stage braking method of 3-phase induction motrois proposed. This brake involves tow stages. The first stage is capacitor self-excitation braking, and the second stage is three-phase magnetic braking. In several applicatons, a low cost and effective brake is required for three-phase induction motor. A mechanical friction brake, typical braking method for induction motor requires external energy sources which is not safe, expensive and requires maintenance. Static and dynamic analyses of the proposed brake scheme are along with analytical result, simulated waveforms and experimental waveforms are compared. The experimental results shows good agreement with the simulated results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.8
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• pp.90-97
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• 2015

This paper discusses to the capability improvement of the 1/4 HP compressor. And, for efficiency improvement of the single phase induction motor, this paper has proposed a casting method to improving the fill factor of the rotor of the single phase induction motor. First, by using FEM, it was analyzed the magnetic flux distribution and the fill factor to the SPIM rotor by the conventional method and the proposed method. And, based on the FEM analysis results, SPIMs are manufactured by the each casting process. Through experiments using dynamometer, they were compared and measured to their efficiencies. In addition, through experiments using Calorimeter, we have analyzed the refrigerating capacity of the compressor of which they were applied. Based on the results of the previous two experiments, they are to verify the validity of the proposed method.

• Computers and Concrete
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• v.21 no.3
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• pp.239-248
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• 2018

This study developed and investigated a precast slab track system partially reinforced with glass fiber reinforced polymer (GFRP) rebars in the transverse direction, which mitigated the loss of track circuit current by reducing magnetic coupling between the rails and steel reinforcements. An electric analysis was conducted and the results of the analysis verified that the GFRP rebars mitigate the reduced current strength produced by electro-magnetic induction. In the study, a three-dimensional finite element method and flexural experiments were used to study the mechanical behavior of the proposed slab track.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.5
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• pp.228-233
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• 2002

A computational method for analysis of the 3 dimensional electro-magnetic induction problems has been developed. The developed method is capable of modeling the induced current and analyzing its characteristics using only scalar Potential at each node. A benchmark model of asymmetrical conductor with a hole is analyzed to verify the application of the developed method. The calculated value of magnetic flux density are compared with the measured value, and the results indicate that the developed method is valid. Also, Comparing with 3-D finite element method (FEM) results, we conformed effectiveness of the developed method for the accuracy and computation times.

• Journal of Acupuncture Research
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• v.30 no.5
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• pp.95-105
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• 2013

Objectives : The purpose of this study is to examine the preparing methods of the traditional acupuncture needle and to interpret the electromagnetic meaning intervened in them. Methods : The overall manufacturing processes of the acupuncture needles in ancient books were surveyed. And the facts that special functional activities were carried out in common in the preparing processes were detected. The reproduction tests for the detected former functional activities were followed. Results : According to the ancient medical books, the traditional acupuncture needles were treated with the magnet through the preparing processes. The reproduction tests provided the fact that the ferromagnetic iron needles treated with the magnet were enhanced their magnetisms. And major techniques of the ancient supplementation and draining can be interpreted as magnetic or induced electromagnetic actions. Conclusions : Considering the electromagnetic characteristics of human body, the magnet treated ferromagnetic iron needles of ancient era and magnetic or induced electromagnetic interpretable manipulation techniques are the historical evidences of magnetic activities of acupuncture. So modern acupuncture therapy should be understood, studied, and reinterpreted as an electromagnetic viewpoint.

• Journal of applied mathematics & informatics
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• v.29 no.5_6
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• pp.1269-1283
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• 2011

Here we consider magneto-convection in a mushy layer which is formed during solidification of binary alloys. The mushy layer is treated as an active porous media with variable permeability. The equations governing the layer are conservation of mass, conservation of heat, conservation of solute, magnetic induction equation, momentum equation governed by the Darcy's law and Maxwell's equations for the magnetic field. To study the second order effects on the flow without solving the second order system, we need to obtain the adjoint system for the flow. This motivates the authors we derive the adjoint system analytically for the mushy layer case. Numerical results of the adjoint system are presented for passive and active mushy layers at the onset of the motion using a set of parameters experimentalists use.

• Journal of Power System Engineering
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• v.15 no.1
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• pp.78-85
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• 2011

In order to design the control system of the magnetic bearing for the high speed 3 phase induction motor, the mathematical modeling was conducted and LQ regulator system was designed. When the plant is controllable and detectable, the nominal stability of LQ regulator could be guaranteed. However, LQ regulator doesn't ensure the robustness of stability and performance for the real system because LQ control is the mathematical optimal theory. In this paper to ensure the robustness of stability and performance for the real system, the control systems are designed by the simulation to the variation system parameters and this method was confirmed as an effective means.