• Journal of the Korean Geosynthetics Society
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• v.15 no.3
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• pp.77-85
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• 2016

This study was conducted to solve the problem such as damage of completed compaction ground using the conventional compaction control method. In this study, a TDR system equipped with a flat type probe has been developed. Also, the Piezoelectric stack, which is an instrument for measuring the elastic wave on the ground, has been added to the developed flat type probe. In this study, the strength variation of reinforced soil with time was determined by using the TDR system. The value of compression and shear modulus increased from 198.65MPa to 541.80MPa and from 125.55MPa to 302.02MPa with time, respectively. Based on the test results, it has been confirmed that the developed TDR system can be used as reinforced effect analysis of soil and compaction control.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.2
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• pp.284-287
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• 2013

In this work, we have fabricated TiC films by using unbalanced magnetron sputtering method with graphite and Ti targets for contact strip application of electric railway. TiC films were deposited with various substrate temperatures. We investigated various properties of TiC films prepared with various substrate temperatures, such as the hardness, surface roughness, friction coefficient, resistivity, FESEM (Field Emission Scanning Electron Microscopy), HRTEM (High Resolution Transmission Electron Microscopy) and XPS (X-ray Photoelectron Spectroscopy). The hardness and friction coefficient properties of TiC films were improved with increasing substrate temperature. These results indicate that the improvement of hardness and resistivity is related to the increase of sp2 clusters in TiC films. And also, the resistivity value of TiC films were decreased with increasing substrate temperature.

• Journal of the Korean Society for Railway
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• v.16 no.6
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• pp.473-481
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• 2013

The purpose of this research is to evaluate the improvements in the strength and injection range of loose ground after injecting $CaCO_3$(created by microorganism reaction). For this purpose, three cases of single-layer (Sand, SP, SW) specimens were made in a 150mm D ${\times}$ 200mm H space and two cases of multi-layer specimens (SW/SP, SP/SW) were made in a 150mm D ${\times}$ 300mm H space. The specimens were made with a relative density of 30% of soft ground and an injection was given over a time of one day. The uniaxial compression strength was measured with a cone penetrometer and the injection range was observed by checking the bulb formation around the injection nozzle. Also, the compositions of the specimens were assessed through XRD analyses. Based on the test results, a compressive strength of 500kPa and 15cm thick cementation were noted due to the cementation of the soil. This implies that there are significant effects of the pore condition and size on bio-grouting technology.

• Journal of the Korean Society for Railway
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• v.18 no.2
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• pp.105-110
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• 2015

This paper presents a $4{\times}1$ beam-forming reader antenna system for a new type of RFID based train position detection technology. The required beamwidth of the reader antenna is analytically expressed for different train speeds. The proposed antenna system consists of four rectangular patch elements and two switching couplers which are designed, without any impedance matching networks, for two different antenna modes. The switching coupler is a rectangular quadrature coupler with Pin diodes connecting its center line and the ground plane. The beamwidth of the antenna when the diodes are off and on is $18^{\circ}$ and $39^{\circ}$, respectively. The proposed antenna system will be used for a real train test in the near future.

• Journal of Korean Port Research
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• v.7 no.2
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• pp.37-60
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• 1993

Because of the rapid growing traffic volumes of cargo, especially between Seoul and Inchon, and lack of investment into transport infrastructure in the past, in Kyong-in area have suffered from the serious traffic congestion in the public-road and the express-way network, But the further expansion of the traffic volume in near future is difficult due to burden of the higher expansion of the traffic volume in near future is difficult due to burden of the higher construction cost. Although the traffic congestion on the Kyung-in railway, is not very serious comparing with the road sector, the shortage of capacity on some main lines becomes emerged as a problem as railway traffic has increased. Unlike these two modes, the water transport, which has been paid relatively less attention for commodity transport in Kyong-in area, has not any constaint in this respect. Han river has been used as a water transport route in Chosun Dynasty which is called Cho-wun. This paper therefore aims to propose the availability of Han river as the alternative water transportation mode, in order to decrease the congestion between Seoul-Inchon by considering the construction of Kyong-in artificial water channel in near future. In this paper, we investigate the availability of Nanji-do as the physical distribution depot connecting with the circulation express way in the national capital distribution depot connecting with the circulation express way in the national capital. We also estimate the traffic volume by using the push-barge carrier (300DWT) in the same channel through the simulation under some assumptions such as ship's turnaround time, speed, etc.

• Journal of Korean Society of Transportation
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• v.32 no.3
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• pp.248-255
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• 2014

Though the Platform Screen Door System (PSD) has received a positive evaluation and is installed in all the Urban Railroad platforms, PSD is not installed in the Intercity Railroad platforms. The limitation of PSD in the Intercity Railroad platforms is due to the fact that first, various types of trains such as KTX, Saemaeul, Mugunghwa, and Nuriro stop at the platforms and their locations of the doors are different and secondly, they are not operated under ATO (automatic train operation). RPSD system currently under research and development, on the other hand, is based on the improved door that slides up and down and can be installed in any Intercity Railroad platform regardless of the length of the train, the location of doors, and the number of doors. This study considers the mechanism of RPSD, develops a manual open/close algorithm, and evaluates the function of RPSD. The results show that the manual open/close algorithm achieves a significant improvement in efficiency when provided with power supply.

• The Journal of Fisheries Business Administration
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• v.36 no.1 s.67
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• pp.103-120
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• 2005

This study aims to examine the change of fish market(魚物市場) and inland brokers(客主, kaegju) on Gunsan(群山), (1899-1919). The increasement of productive capacity in the agriculture and the development of exchange economy in the late period of Chosun Dynasty activated the distribution of fishery products. As a result, the inland brokers who participated in the production and distribution of fishes grew largely. They made the basement of fishery modernization by providing the funds for the fisheries and making the national distribution network. But Japanese fishermen began to hold the domestic market as the Japan government supported legislatively and economically after the opening ports of Korea. On the contrary, the distribution of fishery products had the characteristics different from the production of some. The case of Gunsan which opened in 1899 showed these characteristics as Gunsan is a short distance from Kangkyung(江景), one of three biggest markets and was a base of fishery, That is to say, though the fishery merchants from Japan set up 'a fish market'(魚市場), they didn't hold the sales network on Gunsan, Because the inland brokers on Gunsan had a sales network and began the socio-economic movement. It goes without saying that the instability of price, the difficulties of charge and the racial taste difference in fish made the fish sales from Japan confronted with the difficulties. After Japanese Imperialism enforced the Company Law, the Market Regulation, the Chamber of Commerce Law before or after 1910, Korean inland brokers were disprited and Japanese 'fish market' began to grow largely. These phenomena appeared on Gunsan, too. Especially, the opening of a railway was the main factor which strengthened Japanese 'fish market'. After 1915, Japanese 'fish market' on Gunsan defeated the distribution network of inland brokers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.9
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• pp.4149-4155
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• 2013

High speed machining for higher cutting speed and feedrate lead to a increase of surface quality and material removal rate. This paper presents a study of the influence of cutting conditions on the vibration characteristics obtained by machining with face milling cutter for high speed machining. In this paper, Taguchi experimental design method which is based on orthogonal array table was applied to study vibration characteristics with high speed face milling cutter. The experimental conditions used orthogonal array of $L_{27}(3^{13})$. In this work, design and analysis of experiments is conducted to study the effects of these parameters on the vibration by using the S/N ratio, analysis of variance. Four cutting parameters namely, feed rate, champer length, cutting speed, and depth of cut were optimized with consideration of vibration characteristics.

• The Journal of Engineering Geology
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• v.30 no.1
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• pp.43-57
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• 2020

The objective of this study was to evaluate the performance of high-strength lattice girders as a possible superior alternative to conventional steel arch ribs. For this purpose, the structural characteristics of supports were analyzed using numerical analysis, and their performance was evaluated using maximum bending load tests and tensile tests of the welded joint. According to the results of structural analysis, the optimum size of the upper and lower members and plates is 50 mm × 31.8 mm × 25.4 mm, demonstrating excellent functionality and economic efficiency. High-strength lattice girders of dimensions 55 mm × 30 mm × 20 mm and 85 mm × 30 mm × 20 mm, determined from bending load tests, are found to meet both the reference values and the target values of H-profiles 100 and 125. A review of the ratio of theoretical deflection to actual deflection shows that the high-strength lattice girder developed during this study meets fewer than five of the evaluation criteria for lattice girder deflections proposed by the Federal Railway Department of Germany. Finally, tensile test results reveal that the welded joint of the high-strength lattice girder at the main steel bar-auxiliary steel bar-plate junction exceeds the target value, indicating that the welded joint has sufficient stability.