• Proceedings of the KSR Conference
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• 2009.05a
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• pp.476-482
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• 2009

A signal equipment improvement project for the existing facility ATS to ATP is under construction in Kyung-Bu and Ho-Nam commercial line including 400 rolling stocks. But there was a concern for the interface between KTX OBCS and ATP from the beginning of the project. At present, this is the front burner event. This paper introduces interface checking and predicted failure point between KTX OBCS and ATP improvement system. Through this measure the optimal installation of the ATP will be possible. The study was made under maintenance efficiency including reliability because the KTX signal equipment must qualify the above condition.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.445-450
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• 2008

The primary role of traction power systems is to provide reliable and continuous electrical energy to satisfy traction loads. AC traction substation transforms power from generation company and supply the power to the electric railway power line. Forced outage rate(FOR) of the equipment of substation should be used in the evaluation. This paper proposes the fast and easy way to evaluate by using Bayes' theory when a new equipment is added to the existing substation facility.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.397-398
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• 2013

Fairchild Green Mode off line buck switch for low standby power consumption and high reliability is presented. By reducing operating current and optimizing switching frequency, 20mW power consumption is achieved. High performance trans-conductance amplifier and green mode function improve the ripple and regulation in the output voltage. The conventional $FPS^{TM}$ buck and novel Fairchild buck switch are compared to show the improvement of performance. Experimental results are showed using 2W evaluation board.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1457-1459
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• 2000

The ATO(Automatic Train Operation System) system is equipment for automatic and driverless operation of electric train with minimum control of operator. In this paper, we made ATO system with national technic and passed type test. We are convinced of reliability and safety of the ATO system on the seoul metro 7 line.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.2
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• pp.73-79
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• 1988

A fault current in Simultaneous faults is calulated, which satisfies the reliability for expansion of power scale. New algorithm for analyzing fault current is developed, which calculates exactly thevnin equivalent impedance from fault point by cecomposing increment bus admittance matrix ( Ybus), and fault current is calculated by applying multiport theory. The signeficant results are as follows ` 1) When system fault changes system configulation, equivalent impedance can be calculated simply with this new algorithm. 2) Mutual coupling of transmission line can be calculated efficiently. 3) Simultaneous fault current is analyzed by applying multiport theory, which can be applicable to large scale systems.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.2
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• pp.144-153
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• 1991

This paper presents an algorithm to improve accuracy and reliability in the state estimation of contaminated bad data. The conventional algorithms for detection of bad data have the problems of excessive memory requirements and long computation time. In order to overcome these problems, a measurement compensation approach is proposed to reduce computation time, and the partitioned measurement error model has the advantage of remarkable reduction in computation time and memory requirements in estimated error computation. The proposed algorithm has been tested for IEEE sample systems, which shows its applicability to on-line power systems.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.627-629
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• 2001

The constant voltage transformer(CVT) is a voltage regulator that has a high reliability, a good short circuit characteristic, a high input power factor, and a relative immunity to lightning strike. Moreover, this has a good line regulation without a voltage feedback control. In this paper, the characteristics of CVT for the changes of input voltage and other circuit parameters are investigated.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.49
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• pp.135-142
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• 1999

The objective of this paper is to provide an automatic color image testing system capable of synthetically testing a color element like a color tone and a luminance for a color image displayed on the screen, using a CCD camera and a microprocess. The system consists of a CCD camera, a line conveyor, a camera driving part, a remocon, a remote sensing part, a display and a PC including a color vision board and a CPU board. By applying the system to a process, reliability for a testing result can be improved and the absolute criterion to judge a part can be made.

• Corrosion Science and Technology
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• v.14 no.2
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• pp.85-92
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• 2015

An on-line corrosion rate measurement system was developed using a personal computer, a data acquisition board and program, and a 2-electrode corrosion probe. Reliability of the developed system was confirmed with through comparison test. With this system, the effect of sodium nitrite ($NaNO_2$) as a corrosion inhibitor were studied on iron and aluminum brass that were immersed in sodium chloride (NaCl) solution. Corrosion rate was measured based on the linear polarization resistance method. The corrosion rates of aluminum brass and iron in 1% NaCl solutions were measured to be 0.290 mm per year (mmpy) and 0.2134 mmpy, respectively. With the addition of 200 ppm of $NO{_2}^-$, the corrosion rates decreased to 0.0470 mmpy and 0.0254 mmpy. The addition of $NO{_2}^-$ caused a decrease in corrosion rates of both aluminum brass and iron, yet the $NO{_2}^-$ acted as a more effective corrosion inhibitor for iron. than aluminum brass.

• Imaging Science in Dentistry
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• v.43 no.2
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• pp.105-109
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• 2013

Purpose: Preoperative radiographic assessment of the mandibular third molars is essential to prevent inferior alveolar nerve damage during extraction. The purpose of this study was to assess the reliability of panoramic signs of association between the roots of teeth and the canal, and to compare the panoramic signs with cone beam computed tomography (CBCT) findings. Materials and Methods: CBCT images of 132 impacted mandibular third molars were evaluated to determine the association of the root to the canal. The CBCT findings were compared with the corresponding panoramic images. Logistic regression analysis was used to define the diagnostic criteria of the panoramic images. Results: Among the panoramic signs, loss of the cortical line was the most frequent radiographic sign predicting association (sensitivity: 79.31). Contact of the tooth with the canal was observed in all cases in which the loss of cortical line of the canal or darkening of the roots was found on the panoramic radiographs. Conclusion: Darkening of the roots and loss of the cortical line on panoramic radiographs might be highly suggestive of the risk of nerve injury.