• Korea Trade Review
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• v.47 no.4
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• pp.271-292
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• 2022

In Korea, the road transport industry is pointed out as a major cause of air pollutants, so management control is needed. Existing studies used only positive input and output variables to measure regional efficiency. However, it is necessary to consider the environmental pollution problem in efficiency analysis. In this study, an undesirable SBM analysis using CO₂ was conducted to measure efficiency of domestic regions. In addition, SDM was conducted to examine the ripple effect between domestic regions. As a result of the analysis, the efficiency of the capital area such as Seoul, Gyeonggi, and Incheon was high in the road transport industry. However, the efficiency of the road transportation industry in Daegu and Gangwon was low. In the SDM analysis, it was found that the regional equipment capabilities had a great influence on efficiency. In order to improve efficiency, it is necessary to increase and improve the equipment capacity of the road transport industry.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.12
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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.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.5
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• pp.338-344
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• 2016

Recent trends in transport system for carrying heavy freight are that demands of a high efficiency, economic efficiency, convenience and safety are increased. Conventional transport systems were poor in transport efficiency and economic efficiency. And Safety problems can be caused to products and workers. In order to overcome these problems, an air cushion transport device with a high-pressure air is required. The air cushion transporter is a device for reducing the frictional force of floor surface and lifting the heavy freight by spraying the high-pressure air to the floor. Technology to float and transfer freight using high-pressure air is very convenient and initial cost can be reduced. In this paper, the study on the levitation performance and transport efficiency of air cushion transport system is conducted and verified that air cushion transporter has a significantly higher transport efficiency than conventional heavy handling systems.

• The Journal of the Korea Contents Association
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• v.10 no.12
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• pp.328-341
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• 2010

Korea Trucking Transport Business is one of principal national logistics sector, though, so many issues and problems came to arises, which brought cargo transport system crisis over the country such as logistics enormous jam and traffic. This paper analyzes the efficiency of korean trucking transport business firms using DEA model. We evaluate the CCR, BCC efficiency and RTS of 30 trucking transport firms. We also suggest the trucking transport firms which can be benchmarked based on analyzed information. The result shows that seven enterprises whose values of CCR efficiency are 1, and fifteen enterprises whose values of BCC efficiency are 1. RTS indicates IRS of 16 firms, DRS of 5 firms and CRS of 9 firms.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1504-1511
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• 2005

The efficiency of the hydraulic transport of soil-water mixtures is an important factor in designing and operating a pump & pipeline system and is directly connected with dredging cost and working period. However, the hydraulic transport mechanism in the slurry flow inside the pipeline such as frictional losses, specific energy consumption, deposition velocity has not been well established. In this study a new dredging test loop system was designed and built. It is composed of a slurry pipeline with pipes of different diameters, a centrifugal slurry pump and a diesel engine connected with the slurry pump. and equipped with modern measuring facilities that enable to measure all important characteristics of a transportation system. The objective of this paper is to discuss the efficiency of the hydraulic transport of the Jumoonjin sand-water mixtures in the dredging test loop and to present simple equations induced from the test results of the loop that can express the transport product and the transport productivity.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.625-627
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• 2007

We demonstrated high power efficiency and long lifetime in organic light-emitting diode (OLED) using new electron transport materials (ETMs). Electroluminescent device with these ETMs showed lower driving voltage than that with $Alq_3$. The device lifetime with a new ETM was 2 times longer than that with $Alq_3$.

• International Commerce and Information Review
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• v.9 no.2
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• pp.285-303
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• 2007

As the interest about smooth logistics increases lately, the importance of multimodal transport, which performs the key role of logistics emerges, Through there are many issues respecting multimodal transport, the issue of the efficiency of multimodal transport seems to be the most importance. This paper examine as to the problems & systems of the multimodal transport including transportation document and customs clearance for door to door services. I wish our country will use total logistics automation systems for encouraging multimodal transport chance and make a partial amendment of commercial code including the customs clearance regulation. This study will assist in the development of logistic and the enlargement of multimodal transport transaction.

• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.12
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• pp.983-987
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• 2010

In order to investigate the emission characteristics of the phosphorescent white organic light-emitting diodes (PHWOLEDs) according to various hole transport layers (HTLs), PHWOLEDs composed of HTLs whose structure are NPB/TCTA, NPB/mCP and NPB/TCTA/mCP, two emissive layers (EMLs) which emit two-wavelengths of light (blue and red), and electron transport layer were fabricated. The applied voltage, power efficiency, and external quantum efficiency at a current density of $1 mA/cm^2$ for the fabricated PHWOLEDs were 7.5 V, 11.5 lm/W, and 15%, in case of NPB/mCP, 5 V, 14.8 lm/W, and 13.7%, in case of NPB/TCTA, and 5.5 V, 14.6 lm/W, and 15%, in case of NPB/TCTA/mCP in the hole transport layer, respectively. High emission efficiency can be obtained when the amount of hole injection from anode is balanced out by the amount of electron injection from the cathode to EML by using NPB/TCTA/mCP structured HTL.

• Journal of the Korean Society for Railway
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• v.12 no.4
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• pp.542-547
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• 2009

The objective of this paper is to measure the relative technical efficiency of Korean railway transport service. Previous studies on the efficiency in Korean railway service have carried out before the structural reform of Korean railway industry in 2004, whereas this study used the latest data which reflected the impact of reform. We analyzed the efficiency in Korean railway transport by means of measuring the technical efficiencies of other countries, these were estimated with data envelopment analysis. Using data from 22 railway operators over the period $2000{\sim}2006$, the results indicate that the Korean railway transport has been operated efficiently as compared with others.