• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1697-1698
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• 2006

When the coil with alternating current approaches to the conductor the eddy current flows in conductor. Eddy current is concentrated on the conductor surface and decrescent because of skin effect. In this paper investigated eddy current characteristic that is happened in conductor. Analyzed characteristic using electromagnetic field finite element analysis program that is commercialized to analyze value of eddy current and penetration depth. Analyzed creation value of eddy current and penetration depth in conductor that change operation frequency and the material of conductor, coil outside diameter, inside diameter, position, type of conductor from analyzed eddy current characteristic. The results, using distribution of eddy current and penetration depth data is that will help to forecast ECT(Eddy Current Testing), Eddy current application and use field, eddy current loss.

• Journal of Sensor Science and Technology
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• v.25 no.6
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• pp.399-405
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• 2016

Scent diffuser using micro-pore piezo actuator achieved a commercial success because of its cheap production cost, but it is easy to be use for IT-based contents due to difficulty of scent intensity control. To solve this problem, we control the emission amount of scent diffuser by changing amplitude and frequency of input voltage applied to micro-pore piezo actuator. And, we analyzed the effect of density of cotton core on emission amount and a relationship between hole-size of mesh in piezo actuator and viscosity of scents to design a mechanically optimal scent device.

• Korean Journal of Psychosomatic Medicine
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• v.3 no.2
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• pp.222-231
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• 1995

The author reported a case of short-term dynamic psychotherapy in which relatively good therapeutic results were obtained. And I reviewed several therapeutic factors thought to be important in shot-term dynamic psychotherapy from various literatures. In this case, the frequency of session was limited due to her current reality situations. She had suffered from some adjustmental problems and marital conflict before the onset of the illness. The author could grasp the cental theme of her problems early in treatment period and discussed over it including it's influence on current situation and early childhood with th patient. We also discussed about the relationship between the past and current reality so that she could realize her real problem. At the same time, therapeutic effect was enhanced by family therapy and temporary use of medication.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.385-388
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• 2008

Recently, occurrence frequency of natural disaster decrease but scale of damage increase remarkably by the Climate change due to global warming. Especially, extreme heat become more critical wether problem in the Korean Peninsula. But, we don't have exact threshold about extreme heat. Therefore, to assess the influences by the extreme heat on personal injury, we analyzed statistics on the causes of the daily mortality. And we developed a threshold for extreme heat health watch warning system.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.35.1-35.1
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• 2010

Using the spectroscopic analysis and the theoretical modeling, physical properties of the nearby astrometric binary $\mu$ Cas have been determined. In spite of the well-defined parallax and astrometric orbit, there has been a chronic mass ratio problem between components. Recently, the radius of the primary component has been detected from the optical interferometric observation of the CHARA array. Using the high resolution spectroscopic analysis, we found that $\mu$ Cas have $\alpha$-enhanced chemical composition with respect to the scaled solar abundance by a factor of two. Combining our abundance analysis with recently determined physical properties, the consistent models for $\mu$ Cas have been constructed within the frame work of standard stellar theory. Through a statistical minimization between theoretical model grids, a reliable set of physical dimensions has been defined. Furthermore, the mode oscillation frequency of the best model has been calculated.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.681-684
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• 2001

This paper proposes a new induction heating system composed of a thyristor PWM rectifier with a resonant commutation circuit. The operation of proposed system as first analyzed by a theoretical approach with equivalent circuits. And its verification was performed by computer simulations with EMTP. The proposed system can provide a solution for the power factor problem of the existing high-power induction heating system, which uses the line-commutated thyristor bridge in rectifier side.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.215-218
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• 2001

This paper is proposed a sinusoidal input current multi-level ac-dc converter using transformer. The multi-level converter which controls input current by combining Buck converter to Improve input current characteristics. This method, which is multiplying and duplicating output of converter of equal capacity, is able to control unit power factor of input current, reduce the problem caused by high frequency switching, and apply to high power converter because filter is not necessary The feasibility of the circuit is verified by computer simulation using PSIM

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1582-1591
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• 2014

This paper presents a hybrid sensorless control for an interior permanent magnet synchronous motor (IPMSM) for zero-, low-, and high-speed regions. Many sensorless control methods such as an observer-based estimator have been introduced. However, most of the observer-based estimators have a disadvantage at start-up and in the low-speed region. To solve this problem, a simple strategy of using a hybrid system is proposed by integrating a high-frequency (HF) signal injection method and a full-order flux observer. In addition, an HF signal injection method with only a low pass filter (LPF) is proposed to simplify the hybrid system. The hybrid system achieves high-performance drive throughout the entire speed range. The effectiveness of the proposed hybrid technique is verified by experiments using an 11-kW IPMSM drive system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.222-224
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• 2006

Electronic ballast uses various resonant type filters, which perform many important functions such as filtering the high frequency harmonics, shaping the proper lamp current waveform and regulating the lamp power. In this paper, characteristics of resonant type filters are reviewed and the matching problem between inverter and resonant filter are described. Transfer function which is always necessary for the circuit parameter design is derived in case of LCC filter type as an example.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.11
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• pp.47-52
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• 2015

This paper derives the problems that occur when asynchronous transfer in case of phase, frequency, voltage between the emergency generator and the grid and proposed the countermeasure to solve this problem when the transfer switch replace ATS(Automatic Transfer Switch) with CTTS(Closed Transition Transfer Switch) for the non-interrupting switching. In order to simulate above cases, modelling was used the transient analysis program PSCAD/EMTDC. By using this, the customer installed emergency generator and the grid was implemented. We compared three cases of asynchronous transition based on the basic case and proposed improvement by controlling the governor of emergency generator.