• Proceedings of the KOR-KST Conference
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• 1999.10a
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• pp.335-340
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• 1999

• Proceedings of the Korean Nuclear Society Conference
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• 2003.05a
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• pp.449.2-449.2
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• 2003

• Proceedings of the Optical Society of Korea Conference
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• 1998.08a
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• pp.206-207
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• 1998

• Safe Food
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• v.4 no.2
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• pp.15-18
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• 2009

• 수도
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• v.26 no.2 s.90
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• pp.55-63
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• 2000

• Journal of Drive and Control
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• v.11 no.3
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• pp.66-68
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• 2014

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.10
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• pp.676-681
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• 2015

Recently many studies being carried out to increase the light efficiency of LED. The external quantum efficiency of LED, generally the light efficiency, is determined by the internal quantum efficiency and the light extraction efficiency. The internal quantum efficiency of LED was already reached to more than 90%, but the light extraction efficiency is still insufficient compared with the internal quantum efficiency because the total internal reflection is generated in the interface between the LED chip and air. Thus, we studied about flip chip LED with PSS and performed the optical simulation which find more optimized PSS for flip chip LED to increase the light extraction efficiency. Decreasing of the total internal reflection and effect of diffused reflection according to PSS improved the light extraction efficiency. To get more higher the efficiency, we simulated flip chip with PSS that the parameters are arrangement, edge spacing, radius, height and shape of PSS.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2004.11a
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• pp.361-366
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• 2004

This study has carried out in order to furnish the fundamental material to systemize the lecture room into multimedia in the future, by locating college lecture room as the subject of study, by compare and analyze on acoustic character in both before and after of each improvement. Thereby, now we are about to compare and analyze on physical character of room acoustics in both common lecture room before improvement and the modified multimedia-lecture room after its improvement. Observing the conclusion obtained through experiment, reverberation time in the modified 'lecture room after improvement' became shorter compare with the 'lecture room before improvement', definition and RASTI also improved to be suitable to lecture, and considered that it is able to elevate the intimacy with studying and teaching efficiency, as well.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.27 no.4
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• pp.170-178
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• 2004

As quality becomes a primary leading factor of organizational success, various management strategies have been introduced to improve quality competitiveness. Quality competitiveness, however, is difficult to measure and numerous organizations are struggling to set realistic improvement objectives. The primary purpose of this research is to propose a systematic approach to help the practitioners develop an improvement plan for their organizational quality competitiveness. This approach employs DEA(Data Envelopment Analysis) to evaluate relative efficiency among companies which make efforts to improve their quality competitiveness. It presents an integer programming model to elicit an optimal improvement plan for meeting a target level. A decision support system is also developed for the managers to plan a sequential improvement plan based on both DEA model and the integer programming model.

• International Journal of Quality Innovation
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• v.9 no.2
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• pp.1-9
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• 2008

This paper proposes a scheme to estimate the technical efficiency at child care centers for the less-than-three-year-old infants by Data Envelopment Analysis (DEA) and to manage the quality of care service through implementing flexible and efficient government subsidy system. The result of technical efficiency estimation shows that there exists the heterogeneity in technical efficiency a substantial opportunity for improvement in technical efficiency across child care centers. This result implies that government may bring up the competition by giving subsidy differentially based on efficiency and use the money which has been used inefficiently other purposes. Both can improve the quality of child care service.