• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.319-324
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• 2002

We will report the latest developments in light emitting polymer (LEP) systems developed at CDT. Device performance for spin coated and ink jet printed systems will be described which are state-of-the-art. We will also report on novel driving schemes for both active and passive addressed LEP displays. These drive schemes extend system lifetime as well as lowering power consumption.

• Proceedings of the Safety Management and Science Conference
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• 2008.04a
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• pp.333-337
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• 2008

The Balanced scorecard has been evolved in various function. In the various functional Balanced scorecard, this paper focuses on the reverse logistics BSC, and the decision the weights of Key Performance Indicators. In this paper, a combination of Balanced scorecard and value evaluation based approach proposed multi-criteria provides a more accurate representation of the problem for measuring company.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.157-160
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• 2005

Electrodeless fluorescent lamps utilizing an inductively coupled plasma were found to have a long lifetime and high efficacy and now are used in some indoor and outdoor apllications. This paper gives a basic temperature data of ballast for electrodeless fluorescent lamp 'ULTRA'(E-Tech. ULTRA 150W). The experimental system consist of ULTRA 150W lamp and ULTRA Ballasts.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2003.11a
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• pp.219-222
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• 2003

Electrodeless fluorescent lamps utilizing an inductively coupled plasma were found to have a long lifetime and high efficacy and now are used in some indoor and outdoor applications. This paper gives a basic data of electrodeless fluorescent lamp ‘QL’(Philips). The experimetal system consist of QL 85W/840 lamp and QL 85W S/03 ballast.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1498-1499
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• 2007

In general, ALT can be used to expect the lifetime of electric machines and accelerated stress testing(AST) is used to evaluate the residual life of insulation system. In this paper, a method to design the accelerated life testing(ALT) for reliability qualification of electrical apparatus is represented.

• Proceedings of the Safety Management and Science Conference
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• 2008.11a
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• pp.229-239
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• 2008

This study aims to suggest a performance measurement model reflecting the characteristics of safety evaluation system, especially the model for return manufacturing related to safety, and to develop the S-BSC(Safety-Balanced ScoreCard) measurement model using a weight lifetime value to which a relative weight is applied by using AHP based on the BSC.

• Journal of Applied Reliability
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• v.14 no.3
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• pp.191-196
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• 2014

The importance of railway safety has become increasingly significant domestically as well as internationally, as a series of high speed railway accidents and other major accidents have occurred recently. Especially for the domestic railway, the Korean Railway Safety Law has been revised recently, mandates all the domestic railway operation authorities to render the performance of RAMS and RCM. This study inspects and analyzes the current status of the sensing technology of the electric detection system to tell the status of railway facilities in the highway railway in a real time through a sensor. It also performs the reliability analysis of the electric detection system that is being progressed as a study assignment and suggests the system construction for the higher reliability.

• Journal of information and communication convergence engineering
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• v.6 no.4
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• pp.417-420
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• 2008

Solar electric systems have very little impact on environment, making them one of the cleanest power-generating technologies available. While they are operating, PV systems produce no air pollution, hazardous waste, or noise, and they require no transportable fuels. In PV system design, the selection and proper installation of appropriately-sized components directly affect system reliability, lifetime, and initial cost. In this research, we have studied the PWM(Pulse Width Modulation) signals. I proposed an efficient photovoltaic power interface circuit incorporated with a DC-DC converter and a sine-pwm control method full-bridge inverter. In grid-connected solar power systems, the DC-DC converter operates at high switching frequency to make the output current a sine wave, whereas the full-bridge inverter operates at low switching frequency which is determined by the ac frequency. Thus, it can reduce the switching losses incurred by the full-bridge inverter. Full-bridge converter is controlled by using microprocessor control method, and its operation is verified through computer aided simulations.

• IEMEK Journal of Embedded Systems and Applications
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• v.7 no.5
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• pp.209-217
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• 2012

In the present, Wireless Sensor Network(WSN) has been used for the purpose of the military operation with surveillance systems and for collecting useful information from the natural environment. Basically, low-power, easy deployment and low cost are the most important factors to be deployed for WSNs. Lots of researches have been studied to meet those requirements, especially on the node capacity and battery lifetime improvements. Recently, the study of wireless mesh networks applied into the surveillance systems has been proceeded as a solution of easy deployment. In this paper, we proposed large-scale intelligent multi-layer surveillance systems based on QoS assuring Wireless Mesh Networks and implemented them in the real testbed environment. The proposed system explains functions and operations for each subsystem as well as S/W and H/W architectures. Experimental results are shown for the implemented subsystems and the performance is satisfactory for the surveillance system. We can identify the possibility of the implemented multi-layer surveillance system to be used in practice.

• International Journal of Reliability and Applications
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• v.12 no.1
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• pp.1-14
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• 2011

This paper discusses the stochastic analysis and the statistical inference of a quadratic failure rate semi-Markov reliability model. Maximum likelihood procedure will be used to obtain the estimators of the parameters included in this reliability model. Based on the assumption that the lifetime and repair time of the system units are random variables with quadratic failure rate, the reliability function of this system is obtained. Also, the distribution of the first passage time of this system is derived. Many important special cases are discussed.