• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.69-70
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• 2006

A detailed Investigation of cell structure and electrical characteristic in chalcogenide-based phase-change random access memory(PRAM) devices is presented. We used compound of Ge-Sb-Te material for phase-change cell. A novel bottom electrode structure and manufacture are described. We used heat radiator structure for improved reset characteristic. A resistance change measurement is performed on the test chip. From the resistance change, we could observe faster reset characteristic.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.3
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• pp.451-460
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• 2006

While sludge settles down in a batch column, sludge concentration becomes high. Sludge concentration change is one of the most critical causes of the sludge settling velocity variation. Therefore, sludge concentration change causes sludge index to change. SVI is more sensitive than other sludge indexes to the change of sludge concentration. And if sludge-water interface has reached final height within 30minutes, SVI is not suitable for prediction of sludge settling characteristic, Therefore, SVIs of each sludge are, in some cases, different although each sludge has the same settling velocity. But SVI has been widely used to interpret sludge settling characteristic by a simple testing method. This work has two purposes. The first purpose is to predict sludge settling velocity by using sludge-water interface settling velocity. And the second purpose is to develop new sludge settling characteristic index to exactly interpret sludge settling characteristic by overcoming the limit of SVI.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.1
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• pp.156-163
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• 2006

While sludge is settling in batch column, sludge concentration becomes high. Because the characteristic of sludge settling changes in function of time due to the sludge concentration change, the sludge settling velocity changes too. Also, because the sludge settling characteristic is influenced by a physical characteristic of sludge and a column height etc, it is difficult to exactly measure the sludge settling characteristic. Although the sludge volume indexes, SVI, SSVI and $SSVI_{3.5}$, are used to predict sludge settling characteristic, these indexes are not reliable values. Because the previously established models for sludge settling velocity predict the sludge settling velocity only, it is difficult to predict sluge-water interface height by using those models. The purpose of this experiment is to establish the empirical model which predicts the sludge interface height change with respect to the sludge physical characteristic and the settling condition.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.233-236
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• 2006

In this paper, I try to measure characteristic transmission-reflection by environmental change or solar cell. I keep my eye on the characteristics variation of solar cell as environmental change. As a result, A variation caused by voltage by an effect on the efficiency of solar PV cell. Hence, it is an important variable when a designer plan to make a solar cell.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.844_845
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• 2009

Inductance and back EMF are important parameters in characteristic analysis of brushless motor. Inductance is constant value in surface permanent magnet type brushless motor. But it is change depending on the position of the rotor in interior permanent magnet type brushless motor. So this paper is considering for change inductance in characteristic analysis of brushless motor. Characteristic analysis is executed by the method that three-phase bipolar 120 degree commutation drive type.

• Journal of Sensor Science and Technology
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• v.22 no.1
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• pp.38-43
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• 2013

In this study, the artery's compliance model and the pulsation waveform model was proposed to estimate blood pressure without applying HPF (High Pass Filter) on signal measured by the oscillometric method. The method proposed in the study considered two ways of estimating blood pressure. The first method of estimating blood pressure is by comparing and analyzing changes in pulsation waveform's dicrotic notch region during each cardiac period. The second method is by comparing and analyzing morphological changes in the pulsation waveform during each cardiac period, which occur in response to the change in pressure applied on the cuff. To implement these methods, we proposed the compliance model and the pulsation waveform model of the artery based on hemodynamic theory, and then conducted various simulations. The artery model presented in this study only took artery's compliance into account. Then, a pulsation waveform model was suggested, which uses characteristic changes in the pulsation waveform to estimate blood pressure. In addition, characteristic changes were observed in arterial volume by applying artery's pulsation waveform to the compliance model. The pulsation waveform model was suggested to estimate blood pressure using characteristic changes of the pulsation waveform in the arteries. This model was composed of the sum of sine waves and a Fourier's series in combination form up to 10th harmonics components of the sinusoidal waveform. Then characteristic of arterial volume change was observed by inputting pulsation waveform into the compliance model. The characteristic changes were also observed in the pulsation waveform by mapping the arterial volume change in accordance with applied cuff's pressure change to the pulsation waveform's change according to applied pressure changes by cuff. The systolic and diastolic blood pressures were estimated by applying positional change of pulsation waveform's dicrotic notch region.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.35 no.6
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• pp.59-68
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• 2019

The purpose of this study was to analyze the spatial change of coastal area called Nampo-dong in Busan. And then the subject of research was chiefly concentrated upon the development of southern coast and the land-reclamation based on the commercial facilities after the opening port. There were various reclamation projects in the coastal area of Japanese settlement under the Rule of Japan. Busan Nambin Coast(Currently, Nampo-dong) was one of typical reclamation projects conducted in the southern seashore. Due to the characteristic of coastal area, fishery was developed well and the entertainment industry also grew rapidly with the characteristic of the short distance of urban centre. In this study, we investigated the process of reflecting the characteristic of spatial change that were pursued by communities at that time, particularly through the establishment and change of buildings.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.761-762
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• 2011

• Nuclear Engineering and Technology
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• v.41 no.7
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• pp.929-944
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• 2009

The present study is concerned with the extension of the Effective Convectivity Model (ECM) to the phase-change problem to simulate the dynamics of the melt pool formation in a Light Water Reactor (LWR) lower plenum during hypothetical severe accident progression. The ECM uses heat transfer characteristic velocities to describe turbulent natural convection of a melt pool. The simple approach of the ECM method allows implementing different models of the characteristic velocity in a mushy zone for non-eutectic mixtures. The Phase-change ECM (PECM) was examined using three models of the characteristic velocities in a mushy zone and its performance was compared. The PECM was validated using a dual-tier approach, namely validations against existing experimental data (the SIMECO experiment) and validations against results obtained from Computational Fluid Dynamics (CFD) simulations. The results predicted by the PECM implementing the linear dependency of mushy-zone characteristic velocity on fluid fraction are well agreed with the experimental correlation and CFD simulation results. The PECM was applied to simulation of melt pool formation heat transfer in a Pressurized Water Reactor (PWR) and Boiling Water Reactor (BWR) lower plenum. The study suggests that the PECM is an adequate and effective tool to compute the dynamics of core melt pool formation.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.128-130
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• 2002

This paper describes the operating characteristic analysis of magnetic actuator that is used in breaker using 3-D axisymmetry finite element method. To analyze the operating characteristic of magnetic actuator for configuration change is designed an A, B model and C. Also, For Transient analysis of Electromagnetic system is considered Non-linear characteristic for magnetizing of iron. The analysis results of A, B model and C for magnetic actuator compared with those characteristic respectively.