• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.248-259
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• 2010

In the case of relatively good ground and construction condition in the deep excavation for the construction of subway, railway, building etc., flexible earth retaining systems are often used in an economical point of view. It is generally known that the mechanism of behavior in the flexible earth retaining system is relatively more complicated than the rigid earth retaining system. Moreover in the case of long span strut supporting system the analysis of strut axial force change becomes more difficult when the differences of ground condition and excavation work progress on both sides of excavation section are added. When deeper excavation than the specification or installation delay of supporting system is done or change of ground condition is faced due to the construction conditions during construction process, lots of axial force can be induced in some struts and that can threaten the safety of construction. This paper introduces one example of long span deep excavation where struts and rock bolts were used as a supporting system with flexible wall structure. The characteristics of ground deformation and strut axial force change, the measured data obtained during construction process, were analysed, the effects of relatively deeper excavation than the specification on one excavation side and rapid drawdown of ground water level on the other excavation side were deeply investigated from the viewpoint of mutual influences between ground deformations of both excavation sides and strut axial force changes. The effort of this article aims to improve and develop the technique of design and construction in the coming projects having similar ground condition and supporting method.

• Fire Science and Engineering
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• v.30 no.4
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• pp.59-64
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• 2016

The PSD (Platform Screen Door System) has been installed to enhance the passengers' safety. A total of 592 stations operate the PSD system, which is almost 71.8% of all stations in South Korea. This study compared the opening rate between the PSD and train door, and calculated the exact amount of passengers at peak time. In addition, the evacuation time was simulated by Pathfinder 2015 with the exact input data. Some of the high density stations have extremely high dangerous points about the passengers' evacuation at some situations by the PSD door opening rate. In particular, due to the interference of a fixed door, when it stops at 7 m less than the regular position, its opening rate becomes less than half of the normal state. To solve this problem, it should be made possible to open the fixed door by changing it to an emergency door or improving the PSD module system.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.308-319
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• 2009

In the case of relatively good ground and construction condition in the deep excavation for the construction of subway, railway, building etc., flexible earth retaining systems are often used in an economical point of view. It is generally known that the mechanism of behavior in the flexible earth retaining system is relatively more complicated than the rigid earth retaining system. Moreover in the case of long span strut supporting system the analysis of strut axial force change becomes more difficult when the differences of ground condition and excavation work progress on both sides of excavation section are added. When deeper excavation than the specification or installation delay of supporting system is done or change of ground condition is faced due to the construction conditions during construction process, lots of axial force can be induced in some struts and that can threaten the safety of construction. This paper introduces two examples of long span deep excavation where struts and rock bolts were used as a supporting system with flexible wall structure. And the sections of two examples are 50 meters apart in one construction site, they have almost similar design and construction conditions. The characteristics of ground deformation and strut axial force change were analysed, the similarity and difference between measurement results of tow examples were compared and investigated. The effort of this article aims to improve and develop the technique of design and construction in the coming projects having similar ground condition and supporting method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.1
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• pp.290-297
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• 2016

The performance of track cleaning trains to remove accumulated fine particulate matter in subway tunnels depends on the design of the suction system equipped under the train. To increase the efficiency of the suction system under the cleaning vehicle, this paper proposes a novel dust suction module equipped with both air blowing nozzles and a dust suction structure. Computational Fluid Dynamics (CFD) analysis with turbulent flow was conducted to optimize the dust suction system with a particle intake and blowing function. The optimal angle of the air blowing nozzle to maximize the dust removal rate was found to be 6 degrees. The performance of the track cleaning vehicle can be increased by at least 10 percent under an operation speed of 5km/h.

• Journal of the Korean Solar Energy Society
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• v.38 no.6
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• pp.51-63
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• 2018

Nowadays the bifacial PV system market and its applications are increasing rapidly. The performance of the bifacial PV system take advantage of its rear surface irradiance. Also, the ground albedo, PV module tilt and azimuth, PV module installation height, shading effect and module temperature are factors of bifacial PV system performance. This paper investigates how the performance of bifacial PV system is influenced by above factors. First, we analyzed the energy yield depending on PV module installation by simulation. Secondly, we compare energy performance evaluation of monofacial and bifacial module on different weather condition by experiment. Thirdly, we tested the albedo effect and checked operating characteristics using Dupont Tyvek material for the bifacial PV module. Fourthly, we check the shading effect of bifacial PV module on bypass diode operating. Finally, we applied the bifacial PV module in the nearby subway station for the noise reduction barrier using a qualified simulation program. In summary, we confirm that the energy performance superiority of the bifacial PV module has a lot of application use including road. Also, we have confirmed the bifacial module and inverter design should be considered by rear surface irradiance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.247-249
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• 2016

Corporation, local government and government office provide useful information. Advertisement service is getting various manner. Typical example is electronic display, TV-advertisement and internet or mobile advertisement service. In this paper, I'm study about Taxi-advertisement service still. A similar case is bus or subway advertisement from display. But, Taxi have been only lapping advertisement. Because, Taxi get space restraints. Broadly speaking, Person using Gyeonggi-do to Soeul or Incheon to Soeul is 423million people. On a national basis, it's very amazing figure. However It's just so many person showing one advertisement. So people have no interest in advertisement. So I develop new advertisement system through taxi in the whole country. 254,823 car have passenger personal information and showing people needing advertisement. Also this system get geographical information. This system have high advertisement effect.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.532-534
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• 2004

The advancement of electronics and telecommunication technologies has forced the risk management system for underground metallic structures to evolve into the remote monitoring and control system. Especially, facilities such as gas pipelines, oil pipelines and water distribution lines might make hazardous effect on human safety without continuous monitoring and control. As a result, pipeline engineers have applied cathodic protection system to prevent the degradation of their facilities by corrosion and carried out a periodic monitoring of the pipe-to-soil (P/S) potentials at numberous test boxes along their pipelines. The latter action on a road in downtowns, however, is so much dangerous that the inspectors should be ready to suffer the threatening of their lives and maintenance. In order to minimize these social costs and hazards, a stand-alone type corrosion monitoring equipment which can be installed in test box, store the P/S data for given Belied and send the data by wired/wireless telecommunications is under development. In order to obtain the exact P/S data, however, a reference electrode should be located as close to the pipeline as possible. Actually, the measured potential by a conventional portable reference electrode contain inevitably an IR drop portion caused by the current flow from the cathodic protection rectifier or the subway railroad. To minimize this error, it is recommended that the reference electrode should be buried within 10 cm from the pipeline. In this paper, we describe the design parameters for fabricating the permanent type reference electrode and the characteristics of the developed reference electrode.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.262-265
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• 2003

We can agree that Quality Control in manufacturing industry have been improved successfully, but in construction industry, for example Sungsoo-Bridge broken out, Sampung Department store collapse, subway construction site explosion. and etc, it is difficult to be done. Because in manufacturing industry, they complete each other. If quality is not good. products aren't sold out. to sell more products they have to improve their products quality by themselves. However in construction industry they don't effort to improve quality if they get an order. Because if they get an order only completing their product is their job. There are engineering side, culturing side, and educational side to improve product quality. In this thesis I investigated evaluation system in construction industry. I am going to propose evaluation system by which they have effort to improve the quality even in construction industry.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.3
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• pp.115-121
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• 2017

The efficiency of railway track cleaning vehicle for eliminating fine particulate matter (PM10 and PM2.5) in a subway tunnel depends strongly on the structure of the air blowing and suction system installed under the train. To increase the efficiency of underbody suction system, this paper proposes a novel method to use the Coanda effect for the air blower and dust suction module. In particular, through Computational Fluid Dynamics (CFD) analysis, the flow control device induced by the Coanda effect enables an increase in the overall flow velocity and to stabilize the flow distribution of the suction module at a control angle of $90^{\circ}$. In addition, the flow velocity drop at the edge of the air knife-type blower can be improved by placing small inserts at the edge of the blower. Those 4 modular designs of the dust suction system can help remove the dust accumulated on the track and tunnel by optimizing the blowing and suction flows.

• Journal of the Korean Society of Safety
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• v.21 no.5 s.77
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• pp.22-27
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• 2006

Even though the interior of urban transit vehicle has been changed as a preventing measure against fire to make it inflammable, there remains a possibility of fire breaking out in case of gasoline etc being brought in the subway. However, there is also the possibility that in case if fire toxic gas is generated and hot air spreads in carriage it will prove very dangerous for people sitting inside. This is a comparative study where we compare simulation results with model examining the time and direction the fire spreads when it breaks out. Also there is vertical distribution of temperature in carriage where the fire spreads out. This study is about demonstrating how to establish smokeless system in urban vehicle, about its necessity, and about vehicle system restructuring. This study also makes an effort to find more advanced method for efficient fire safety in trains. In existing vehicles, in case of fire, the smoke can't go out when doors are closed and hence it spreads in whole train. Even though the method of using ventilation or exhaust established inside the carriage to throw smoke out is much better than the way of opening end doors in each carriage, this study is trying to do research on second way. Through simulation we see that in second case, even though not as good as the first one, smoke can exit through gates. Even though the first method is better, the second can also be uses to let fire out. We can know that in the first case as the smoke can exit out faster, it provides more safety for people. So this system provides better fire safety condition.