• 한국전기전자재료학회논문지
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• 제17권12호
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• pp.1341-1346
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• 2004

The OLED research is gone for two directions. One is material development research, and another one is structural improvement part. All two are thing to heighten luminescence efficiency of OLED. n other to improve luminescence efficiency of OLED Electron - hole pairs must consist much more in the device Their profiles are sensitive to mobility velocity of electrons and holes. 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 suggest improving the efficiency of OLEDS would be to balance the injection of electrons and holes into light emission layer of the device. And, we improve understanding of the various luminescence efficiency through experiments and numerical analysis of luminescence efficiency in variable hole carrier transport layer's thickness.

• 동아시아경상학회지
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• 제9권2호
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• pp.1-10
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• 2021

Purpose - The purpose of this study is to measure the efficiency of social security expenditure in 31 provinces, cities and autonomous regions in China and proposes corresponding improvement plans. Research design, data, and methodology - The data were obtained from the statistical yearbook of each province. The BCC and CCR models of DEA model and Malmquist index are used to analyze the efficiency, and the input-output index is expanded. Result - The results show that the social security performance of the Chinese government has improved on the whole despite the unbalanced development in different regions. Each region should look for strategies to improve the efficiency of social security according to its own problems. The study suggests that provinces affected by TCI should improve their internal environment, such as raising social security fund structure and strengthening fund supervision, to improve efficiency. Areas affected by TECI need to be more responsive to policy, socio-economic and technological development. Conclusion - The research conclusion can provide reference for Chinese provinces to improve the efficiency of social security expenditure in the future. This study is not comprehensive enough in the selection of input-output indicators, which can be further expanded in the future.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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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.

• The Journal of Asian Finance, Economics and Business
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• 제8권9호
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• pp.177-187
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• 2021

The purpose of the research to evaluate the efficiency and productivity growth rate of some Vietnamese commercial banks in the period 2008-2020. Using input and output selection theory, the author selected 2 models, estimating the efficiency for model 1 and estimating the yield change for both the models. We have built a model to estimate the efficiency and calculate as well as decompose the productivity growth of Vietnamese commercial banks during the period of active mergers and acquisitions activities in the banking system. Based on the results of the efficiency estimation, TFP shows during mergers and acquisitions, efficiency fluctuates but in an inverted U-shape (increasing from 2008-2011 but decreasing from 2013 to 2020). The estimated results of the impact assessment model show that FDI reduces the efficiency of banks. Productivity analysis shows that 6 out of 23 banks in the study period had positive TFP growth (tfpch > 1) due to technical progress and management efficiency. The findings of this study suggest that Vietnam's commercial banking system has many opportunities to improve operational efficiency in many aspects. In which, there are opportunities to increase credit, improve governance as well as improve the technology level of each bank. In addition, along with traditional products such as deposits and loans, diversification with a wide range of products and services is an important factor to enhance customer experience and demand in commercial banks.

• 한국항해항만학회지
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• 제36권7호
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• pp.535-544
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• 2012

In order to improve the overall ASEAN maritime transport network, each port's efficiency is regarded as a crucial factor that should be calculated periodically. This study evaluated the relative efficiency of container port operations of 32 ports belonging to 9 ASEAN nations using Data Envelopment Analysis (DEA). It found that 2 out of 32 ports in 2010 were measured as efficient ports. This study yielded two major findings. Firstly, the ports assessed as inefficient need to benchmark similar ports in size and structure from the ports that are assessed as efficient to improve their efficiency. Secondly, these results could be used to determine potential candidates and country for an international port development co-operation programme with Korea to improve the performance of the entire ASEAN port network by developing the infrastructures of ill-equipped ports.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2017년도 전력전자학술대회
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• pp.1-2
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• 2017

In this paper a method is proposed to optimize the inductor design of PFC boost converter with maximum efficiency at rated load. The variables of switching frequency, the number of turns, core size and permeability are selected to improve the efficiency. The experimental result shows the proposed inductor design method can lead a higher efficiency when compared with the typical inductor design method.

• Journal of Electrochemical Science and Technology
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• 제1권2호
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• pp.69-74
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• 2010

Methodologies to improve photovoltaic performance of dye-sensitized solar cell (DSSC) are reviewed. DSSC is usually composed of a dye-adsorbed $TiO_2$ photoanode, a tri-iodide/iodide redox electrolyte and a Pt counter electrode. Among the photovoltaic parameters of short-circuit photocurrent density, open-circuit voltage and fill factor, short-circuit photocurrent density is the collective measure of light harvesting, charge separation and charge collection efficiencies. Internal quantum efficiency is known to reach almost 100%, which indicates that charge separation occurs without loss by recombination. Thus, light harvesting efficiency plays an important role in improvement of photocurrent. In this paper, technologies to improve light harvesting efficiency, including surface area improvement by nano-dispersion, size-dependent light scattering efficiency, bi-functional nano material, panchromatic absorption by selective positioning of three different dyes and transparent conductive oxide (TCO)-less DSSC, are introduced.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2004년도 하계종합학술대회 논문집(1)
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• pp.111-114
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• 2004

Sensor networks are deployed with a limited energy source. Thus, energy efficient design can be challenging. This paper has been studied optimal packet length with energy efficiency for sensor networks. And using Power Management can not improve energy efficiency. Power Management is turning off transceiver when transceiver is idle statue. We show that BCH code for error control can improve energy efficiency better than Convolutional code.

• 한국정보통신학회논문지
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• 제18권8호
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• pp.1847-1853
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• 2014

이동통신 시스템의 OFDMA 방식은 신호에 대한 PAPR(Peak to Average Power Ratio) 값의 증가를 가져왔다. 이동통신 시스템 전력 소모의 대부분을 차지하는 전력 증폭기에 대한 효율 개선은 매우 중요한 핵심 기술이다. 전력 증폭기의 선형 특성 개선을 위해 디지털전치왜곡 기술을 사용하였으며, 전력 증폭기의 효율 개선을 위해 비대칭 도허티(Asymmetric Doherty) 방식을 사용하였다. 본 논문에서는 기존 비대칭 도허티 구조와 다른 새로운 구조의 비대칭 도허티 구조를 제안하였다. 제안하는 새로운 구조의 비대칭 도허티 방식에서는 전력 증폭기 구동단을 주경로와 첨두경로로 분리하였으며, 위상 변환기를 이용하여 도허티 증폭기의 전력 결합 특성을 개선하였다. 또한 구동단 첨두 증폭기 gate bais에 대한 포락선 추적 기술을 적용하여 효율을 개선하였다.

• 전기학회논문지
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• 제59권10호
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• pp.1823-1831
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• 2010

This paper proposes an automatic tracking control algorithm for efficiency improvement of photovoltaic generation. Increasing the power of PV systems should improve the efficiency of solar cells or the power condition system. The normal alignment of the PV module always have to run perpendicular to the sun's rays. The solar tracking system, able to improve the efficiency of the PV system, was initiated by applying that to the PV power plant. The tracking system of conventional PV power plant has been studied with regard to the tracking accuracy of the solar cells. Power generation efficiency were increased by aligning the cells for maximum exposure to the sun's rays. Using a perpendicular position facilitated optimum condition. However, there is a problem about the reliability of tracking systems unable to not track the sun correctly during environmental variations. Therefore, a novel control algorithm needs to improve the generation efficiency of the PV systems and reduce the loss of generation. This control algorithm is the proposed automatic tracking algorithm in this paper. Automatic tracking control is combined the sensor and program method for robust control in environment changing condition. This tracking system includes the insolation, rain sensor and anemometer for climate environment changing. Proposed algorithm in this paper, is compared to performance of conventional tracking control algorithm in variative insolation condition. And prove the validity of proposed algorithm through the experimental data.