• Journal of Korean Society for Quality Management
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• v.23 no.4
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• pp.128-147
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• 1995

An accelerated life testing(ALT) for aluminum electrolytic capacitors is conducted and analyzed. A testing equipment, which consists of part fixtures, relay board, controller, video bridge and microcomputer, is made for the ALT. Load factors are temperature with four levels and voltage with three levels. Base on 'optimized 4:2:1 plan', 2,000 electrolytic capacitors are allocated at 12 experimental conditions(; 4 levels of temperature ${\times}3$ levels of voltage), and the ALT is conducted. From the experimental results, an acceleration model is derived and acceleration factors are estimated. A discussion on the experimental results is included.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.2
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• pp.84-91
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• 2014

This paper introduces the application of supervisory monitoring system for substation automation based on IEC 61850. The objective of proposed system is detection of such a malfunction or degradation of devices. The supervisory monitoring procedure consists of a two step - topology processor and state estimation. The topology processor using artificial intelligence is a preprocessing step of state estimation. Topology processor identifies the topology structure of switches in substation and detects an error of ON/OFF state data. The state estimation is an algorithm that minimizes an error between optimal estimation values and real values. The proposed system is applied to standard digital substation based on IEC 61850 for performance verification.

• Microbiology and Biotechnology Letters
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• v.24 no.6
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• pp.738-742
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• 1996

An efficient packed-bed type biofilm reactor charged with immobilized phototrophs was developed to treat organic wastewater at an extremely high volumetric loading rate. The packed bed reactor (PBR) charged with porous ceramic beads was superior to a fluidized-bed reactor suspended with activated carbon powders in terms of many aspects such as BOD removal efficiency, operational stability, and overall economics. For wastewater with BOD concentration as high as 20, 000mg/l, the BOD removal efficiency was maintained above 90% when the hydraulic retention time (HRT) was longer than 1 day. The allowable volumetric BOD loading rate of this reactor (20gBOD/l day) is more than ten-folds higher than that of an ordinary activated sludge method. The behaviour of the reactor was represented well by a Monod type kinetic equation with a maximum specific BOD loading rate(P) of 22.2gBOD/l day and a half saturation constant(K$_{s}$) of 1, 750 mgBOD/l.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.412-415
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• 2008

It is known that the address discharge delay time during an address period strongly depends on the wall charge leakage. It was observed that the wall charge leakage during an address period is related to both the address width and the ambient temperature. Accordingly, the effects of address electrode width on the address discharge and wall voltage variation during an address period were examined under variable temperatures.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.111.4-111
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• 2001

In this paper, an adaptively tuned dynamic absorber is proposed. The adaptively tuned dynamic absorber is a dynamic absorber whose stiffness is tuned so that the natural frequency of the absorber coincides with the operating or natural frequency estimated by an adaptive algorithm. The feature of this absorber is as follows. It has an electrodynamic device for the stiffness control. Using Lorenz´s force, it changes the stiffness by changing the applied current. The change of stiffness results in the natural frequency shift, because its mass and damping coefficient are fixed. We may reduce the vibration of the overall system by tuning the natural frequency of the dynamic absorber to the resonant frequency of the structure, when the dominant single tone oscilation occurs in the system ...

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.364-366
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• 1997

An experimental helical resonator plasma system that can be applied to the next generation semiconductor processing was fabricated and its characteristics was investigated. Helical resonator plasma can operate both in a capacitive and an inductive mode. Such sources will produce an extended plasma for the capacitive mode and a plasma concentrated in the resonator for the inductive mode. Plasma parameters were measured with Double Langmuir Probes. Plasma densities of $10^{11}{\sim}10^{12}cm^{-3}$ were produced in argon for pressure in the $2{\sim}120\;mTorr$ range. From the results, we conclude that helical resonator plasma can be applied to the next generation semiconductor processing.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.4
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• pp.37-42
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• 2004

End-milling have been widely used in aircraft, automobile part and moulding industry. However, various working factors such as spindle speed, feed rate and depth of cut in end-milling have an effect on spindle vibration. There it is demanded the quantitative analysis of spindle vibration in order to get the optimum surface roughness. This study was carried out to analyze an influence of working factors on spindle vibration by design of Experiment. The results are shown that mathematical model of regression equation for an influence of working factors on vibration acceleration of spindle in end-milling by regression analysis is presented.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.144-150
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• 2001

Considered is non-symmetric contact traction induced by the tilting of a contact body and/or by a far field bulk tensile load to the other body. The problem is under the regime of plane strain. General profile of the contact end is incorporated and partial slip condition is supposed. As an example contact configuration, an indentation of a punch with rounded corners onto a half plane is studied. The variation of the internal stress field due to the tilting and the bulk tension is investigated. An edge crack problem is analyzed to examine the influence of the non-symmetric traction. It is shown that the tilting of a punch does not influence the behaviour of the crack. Rather, the effect of the bulk tension on the cracking behaviour is found considerable.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.872-875
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• 2002

This paper presents an efficient method of estimating the correlated color temperature of an input color image and of generating a converted color image that can approximate the new target color temperature. After extracting the potential reference white region for an uncalibrated color image and estimating its correlated color temperature, the color conversion method produces a new color image with a target color temperature. Speed improvement and memory reduction have been achieved by using a simple transfer method without involving the CIE XYZ conversion step.

• Journal of Power Electronics
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• v.11 no.4
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• pp.424-429
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• 2011

In this paper, the simulator of an on-line monitoring system for the range extender electric vehicle has been developed. The messages from the four control modules, the air pressure and fuel level sensors data, and the on/off switching states of 31 indicator lamps can be received through the control area network (CAN), and displayed on the graphic panel. The simulator was designed using the four DSP boards, variable resistors, and toggle switches instead of the four control modules, sensors, and switching state of indicator lamps on an actual series hybrid electric vehicle (SHEV) bus, respectively. The performance of the monitoring technologies was verified with the simulator at the laboratory, and then it was tested on an actual SHEV bus. The simulator is very useful at the initial development of the monitoring system at the hybrid-type or electrical vehicles.