• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.7
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• pp.97-105
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• 2014

This article examines the causality relationship among SMP, base-load share, LNG import price, and exchange rate in Korean power market during 2002~2012, using unit root test, cointegration test, and vector error correction model(VECM). The cointegration test shows that 4 variables without unit root have been in the long-run causality. As the results of ECM, SMP is analyzed to have been unilaterally caused from LNG import price and base-load share in the shot-run, while it has been unilaterally caused from LNG import price and exchange rate in the long-run. This article has the following policy implications: the adjustment of exchange rate to reduce he risk of LNG import price and the proper securement of base-load share for the long-run stability of SMP.

• Journal of the Korean Society for Railway
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• v.7 no.1
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• pp.37-48
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• 2004

In this paper, I explain the situations and problems which are focused on the rail freight system. We have a many problems, which have been showed the long freight logistics time, and inadequate fare system. And rail freight system does not have a efficient marketing system, and unit load system. Therefore rail freight has been decreased modal share, which is estimated from 9.65% in 1995 to 6.25% in 2001(ton base). Recently, EU nations and America rail freight system reveals a good outcome, which keeps the balance in the black. The main factors which go into the black, is the enlargement the investment in rail freight and efficient management focusing on the unit load system, fare system, and personnel management. I suggest the several improvement ways, which will be helpful to advance the rail freight system. Fistly, I suggest the speed up the freight rail and efficient fare system. Secondly, I propose the unit load system and the regulation the truck focusing on curtailment of the social cost. Lastly, I make an overture of establishment the comprehensive logistics system.

• Computers and Concrete
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• v.33 no.4
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• pp.373-384
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• 2024

In this study, a novel mountain train system was developed that can run along a steep gradient of 180 ‰ and sharp curve with a minimum radius of 10 m. For this novel mountain train, an embedded precast concrete rack rail track was implemented to share the track with an automobile road and increase constructability in mountainous regions. The embedded rack rail track is connected to a hydraulically stabilized base (HSB) layer with shear anchors, which must have sufficient longitudinal resistance because they bear most of the traction forces originated from the rack rail and longitudinal loads owing to the steep gradient. In addition, the damage to the shear anchor parts, including the surrounding concrete, must be strictly limited under the service load because the maintenance of shear anchors inside the track is extremely difficult after installation. In this study, the focus was made on the shear anchor behavior and design an embedded rack rail track, considering the serviceability and ultimate limit states. Accordingly, the design loads for mountain trains were established, and the serviceability criteria of the anchor were proposed. Subsequently, the resistance and damage of the shear anchors were evaluated and analyzed based on the results of several finite element analyses. Finally, the design method of the shear anchors for the embedded rack rail track was established and verified.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.4
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• pp.750-757
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• 2017

Recently, mobile internet traffic has rapidly increased as the huge increase of the smart phone and mobile devices. D2D get attention, because D2D is known that it reduce the traffic load of the base station and also improves the reliability of the network performance. However, D2D has a problem that the efficiency decreases as interference is increased. In this paper, we propose a resource allocation scheme to use the resources efficiently when the D2D link share the cellular resources in the cellular network based the uplink. D2D communication utilizes the location information for allocating resources when the eNB know the location of all devices. The proposed scheme select some cellular user using location informations in order to ensure performance of the D2D communication. and D2D link choose cellular user that performs resource allocation using only selected cellular user. Simulation results show optimal value of resource selection in order to ensure most performance of the D2D communication.