• Transactions on Electrical and Electronic Materials
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• v.18 no.2
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• pp.70-73
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• 2017

We investigated n-i-p type single junction hydrogenated amorphous silicon oxide solar cells. These cells were without front surface texture or back reflector. Maximum power point efficiency of these cells showed that an optimized device structure is needed to get the best device output. This depends on the thickness and defect density ($N_d$) of the active layer. A typical 10% photovoltaic device conversion efficiency was obtained with a $N_d=8.86{\times}10^{15}cm^{-3}$ defect density and 630 nm active layer thickness. Our investigation suggests a correlation between defect density and active layer thickness to device efficiency. We found that amorphous silicon solar cell efficiency can be improved to well above 10%.

• Journal of the Korean Operations Research and Management Science Society
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• v.35 no.3
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• pp.59-68
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• 2010

Improving productive efficiency is important for strengthening a competitiveness of coastal fisheries. This paper examines the productive efficiency of a sample of coastal gillnet fishing business units by estimating a stochastic frontier analysis (SFA) and a data envelopment analysis (DEA) approaches and compares those estimates obtained from two approaches. The estimated mean productive efficiency by SFA is 77.6% and the mean productive efficiencies obtained for the VRS and CRS DEA are 75.9% and 45.7%, respectively. The joint use of SFA and DEA for estimating efficiency is also discussed.

• Journal of the Korean Solar Energy Society
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• v.31 no.3
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• pp.57-66
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• 2011

A Photovoltaic/Thermal(PVT) solar system consists of PV module and thermal absorber plate which convert the absorbed solar radiation into electricity and heat. Meaningful researches and development (R&D) on the PVT technologies have been performed since the 1970s. This paper presents a review of the previous works covering the various types of PVT and their performance analysis in terms of electrical and thermal efficiency. This review compares electrical and thermal efficiency of the different types of PVT collectors and analyzes the parameters affecting PVT performance. Based on the literature review, box channel type PVT with unglazed, or flat plate PVT with glazed have the highest efficiency among them. From the literature review, R&D should be carried out aiming at improving their overall electrical and thermal efficiency, cutting down the cost, and making them more competitive in the energy consumption market.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1002-1006
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• 2004

The studies on OLED(Organic Light-Emitting Diode) materials and structures have been researched in other to improve luminescence efficiency of OLED. Electrons and holes are injected into the devices, transported across the layer and recombine to form excitons, their profiles are sensitive to mobility velocity of electrons and holes. A suggested means of improving the efficiency of LEDs would be to balance the injection of electrons and holes into light emission layer of the device. In this paper, we demonstrate the difference of velocity between hole and electron by experiments, and compare with a data of simulation and experiment changing hole carrier transport layer thickness, so we get the optimal we improve luminescence efficiency. We improve understanding of the various luminescence efficiency through experiments and numerical analysis of luminescence efficiency in the hole carrier transport layer's thicknes.

• Korean Management Science Review
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• v.26 no.1
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• pp.127-136
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• 2009

This paper purposes analyzing how task assignments influence on business process efficiency, and improving business process efficiency in Business Process Management (BPM) environments. For this purpose, task assignment is categorized into dynamic assignment and static assignment. Dynamic assignment binds a user to a task at process run-time, whereas static assignments assigns a task to a user at process build-time. So far, the influence of task assignment methods has not been studied. We, in this paper, analyze the business process efficiency using two different assigning rule, in terms of cycle time as a efficiency measure. The comparison result can provide a guideline for a company who wants to employ commercial BPM systems.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.250-255
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• 2011

A Photovoltaic/Thermal(PVT) solar system consists of PV module and thermal absorber plate which convert the absorbed solar radiation into electricity and heat. Meaningful researches and development (R&D) on the PVT technologies have been performed since the 1970s. This paper presents a review of the previous works covering the various types of PVT and their performance analysis in terms of electrical and thermal efficiency. This review compares electrical and thermal efficiency of the different types of PVT collectors and analyzes the parameters affecting PVT performance. Based on the literature review, box charmel type PVT with unglazed, or flat plate PVT with glazed have the highest efficiency among them. From the literature review, R&D should be carried out aiming at improving their overall electrical and thermal efficiency and cutting down the cost, making them more competitive in the energy consumption market.

• Journal of the Korea Society of Computer and Information
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• v.23 no.12
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• pp.203-209
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• 2018

This study analyzed the employment efficiency of Korean colleges and universities using DEA(2015 GOMS), which was surveyed by the Ministry of Employment and Labor and the Korea Employment Information Service. The input variables were employment program participants, language educators, family economic applicants, and employment targets. As a result, the college was more efficient than the college and the college was relatively ineffective. The contribution of input and output contributed the highest efficiency with 99.9% of the participants in the employment program, and the possibility of improving the efficiency of the language educator was the highest at 70.04. Based on the results of the above research, it suggests the necessity of activation of employment programs and activation of language training in each university. Future studies will need to study the efficiency of universities nationwide.

• Journal of Digital Convergence
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• v.17 no.12
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• pp.181-190
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• 2019

The purpose of this study is to evaluate the operational efficiency of Chinese e-commerce companies and to present measures to improve efficiency. This paper selected 16 enterprises as the research objects, from the e-commerce demonstration enterprises of the Ministry of Commerce of China in 2017-2018, to conduct an empirical study on the operating efficiency of e-commerce enterprises. By using DEA method, we selected 3 input and 2 output indicators to measure the input-output efficiency of enterprises from input-oriented. Using different model in DEA, we calculated the technical efficiency, pure technical efficiency and scale efficiency, also efficiency based on the sample of 2018 and horizontal analysis from 2016 to 2018. The analysis showed that the overall efficiency of Chinese e-commerce companies was continuously improving, and that their business capabilities and business scale were also gradually improving. Through the calculation of efficiency, we evaluated the competitiveness of the e-commerce demonstration enterprises, and explored measures to improve their management efficiency. At the same time, it put forward some reasonable suggestions to adjust the scale, and enhance the competitive advantage.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.12a
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• pp.539-545
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• 1999

• Proceedings of the Korea Technology Innovation Society Conference
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• 2006.11b
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• pp.495-505
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• 2006