• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.397-398
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• 2016

This paper analyzes switching losses, efficiency and temperature depending on Si and SiC devices applied in two stage AC-DC converter. To evaluate the charge and discharge performance and stability of the battery pack, there is a need for a battery pack testing system. To do battery charge and discharge experiment used in battery pack test, A topology, two stage AC-DC converter, has been built. SiC devices more decrease switching losses than that of Si. Also, cooling system was applied in Si and SiC devices. When using SiC devices, it can be confirmed that the size of heat sink is reduced for small loss.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.4
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• pp.337-344
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• 2000

The present study describes a one-dimensional modeling of encapsulated ice storage tanks. The thermal transmittance of capsules in this model uses the results from the Arnold's experimental $study^{(2-3)}$.In this model, ice storage tank is partitioned by several control volumes for the analysis, each having same number of capsules. The model is validated by the comparison of the measured data from an ice storage tank installed at a building with the capacity of 1200 ton-hrs and the simulated results with the same inlet brine temperature conditions into the tank.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.9
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• pp.904-908
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• 2008

Every autonomous system like a robot needs a power source known as a battery. And proper management of the battery is very important for proper operation. To know State of Charge(SOC) of a battery is the very core of proper battery management. In this paper, the SOC estimation problem is tackled based on the well known Extended Kalman Filter(EKF). Combined the existing battery model is used and then EKF is employed to estimate the SOC. SOC table is constructed by extensive experiment under various conditions and used as a true SOC. To verify the estimation result, extensive experiment is performed with various loads. The comparison result shows the battery estimation problem can be well solved with the technique proposed in this paper. The result of this paper can be used to develop related autonomous system.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.302-304
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• 1997

Chemical structure and electrical properties such as water treeing and space charge accumulation of various raw materials(XLPE) used for power cable insulation were investigated. It was found that chemical structure was changed after crosslinking reaction and every materials have different amounts of DCP and antioxidant. Electrical properties were also changed after extraction using $CHCl_3$ and xylene. Water tree length was smaller with additives such as DCP and antioxidant and bigger with low molecular weight components of polyethylene than that of extracted samples. Heterocharge was changed into homocharge after extraction. This shows that additives and low molecular weight components of polyethylene cause the heterocharge.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.167-170
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• 2005

The mechanism of striation in the coplanar- and matrix-type plasma display panel (PDP) cells has been studied using the particle-in-cell Monte-Carlo Collision (PIC-MCC) model. The striation formation is related to the ionization energy of neutral atoms and the well-like deformation of space potential by space charge distribution. Negative wall charge accumulation by electrons on the MgO surface of the anode region is also one of the key factors for the formation of striation. The clearness of the striation phenomenon in PIC-MCC code in comparison with fluid code can be explained by using nonlocal electron kinetic effect.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.05a
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• pp.255-258
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• 2006

In this paper, the new method which is monitoring quantity of particles using by ion-counter has been developed. ISPM system is composed by Gerdien type ion-counter (house-made), DC power supply and electrometer. Ion-counter applied positive voltage could detect only positive charged particles. Therefore charged particles to Boltzmann equilibrium distribution or to some identified charge distribution can be detected by ion-counter. Ion-counter could install on the exhaust line of process equipment since pressure loss is structurally low. ISPM system has been certified by comparison with the result of SMPS (Scanning Mobility Particle Sizer) system. The relation coefficiency is above 0.98 about $20{\sim}300nm$ particles with identified charge distribution under $0.1{\sim}10.0$ Torr.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.10 no.S_3
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• pp.121-126
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• 2001

The techniques of pulse and cyclic voltammetry were applied to the determination of (E$_{1}$2)$_2$-(E$_{1}$2)$_1$ for two-step electrochemical charge transfers. In addition, a simple amplitude was derived far the dependence of the differential pulse response on (E$_{l}$ 2/)$_1$ and (E$_{1}$2/)$_2$. and the use of peak to peak separation in cyclic voltammetry and differential pulse methods was evaluated. A comparison of the comproportionation constants(Ke) from differential pulse and cyclic voltammetry methods exhibited a good agreement within 5%.

• Korea Journal of Hospital Management
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• v.20 no.1
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• pp.53-64
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• 2015

Our objective was to evaluate differences in linear regression versus multilevel(cross-level interaction model) modeling for affecting factors lumbar discectomy. The data were used in 2011 patients with HIRA sample data. Total number of analysis is 3,641 patients and 248 hospitals. The results of research model showed that the type and location of the hospital-level factors were significant. However, all factors of patient-level were similar in the two models. Therefore, it requires the selection of an appropriate model for a more accurate analysis of the influencing factors in the daily medical charge.

• Journal of Power Electronics
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• v.13 no.1
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• pp.51-58
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• 2013

This paper proposes the power conversion mechanism of a bailer-charge-transfer zero-current-switching (CT-ZCS) circuit. The operation modes are analyzed and researched using state trajectory equations. The topology of CT-ZCS based on soft-switching inverters offers some merits such as: tracking the input reference signal dynamically, bearing load shock and short circuit, multiplying inverter N+1 redundancy parallel, coordinating power balance for easy control, and soft-switching commutation for high efficiency and large capacity. These advantages are distinctive from conventional inverter topologies and are especially demanded in AC drives: new energy generation and grid, distributed generation systems, switching power amplifier, active power filter, and reactive power compensation and so on. Prototype is manufactured and experiment results show the feasibility and dynamic voltage-tracking characteristics of the topology.

• Journal of the Optical Society of Korea
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• v.11 no.3
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• pp.133-137
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• 2007

We compare electroabsorption modulators (EAMs) with multiple quantum wells (MQWs) based on InGaAs(P)/InP and InGa(Al)As/InAlAs material systems. We carefully choose the quantum-well structures so that the structures based on different material systems have similar band-offset energies and excition-peak wavelengths. Assuming the same light wavelength of $1.55{\mu}m$, we show the transfer functions of EAMs with each quantum-well structure and calculate the escape times of photogenerated charge carriers. As the heavy-hole escape time of the quantum well based on InGaAs(P)/InP is much longer than those of photogenerated charge carriers of InGa(Al)As/InAlAs, the EAM based on the InGa(Al)As/InAlAs material seems to be more suitable for high-optical-power operation.