• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.189-192
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• 2008

The solar photovoltaic Power generator can get more power with the higher solar radiation quantity. However, if the higher solar radiation quantity on cell becomes high temperature, the efficiency of generate will be reduced. To install cooling system for this kind of device can be the way to solve high temperature problem on cell but another problems after install it such as increasing of solar generated quantity problem, cost to install cooling system and cost to be maintained cooling system weren't discussed to practical use this system. So the present paper described about effect and commercial business possibility of cooling system.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.848-853
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• 2005

The objective of this paper is to address to the providing an adequate noise and vibration solution, required for High Speed Rail while maintaining the stability criteria of the ChonAn station structure, the first constructed in Korean High Speed Railway. The significant acoustic pressure level will be induced by the high speed trains passing-by. Therefore, the high level study of this case is necessary. The acoustic pressure level of 85 dB(A) inside the ChonAn station is expected, and the spaces below concrete slab are not suitable for commercial purpose, thus installation of filtering systems (spring boxes containing viscous dampers, ballast mats and acoustic shield) are provided to reduce the effect of the noise and vibration to acceptable level of 55 dB(A). But, a major drawback of application of the previously conducted experimental results was that the actual effect of installation of filtering system was never been validated. Therefore, the acquisition of noise and vibration on the present structure were obtained and compared to the computer simulations. These predicted the behavior of the station reasonably well. Also, the installation of filtering systems gave the superior reduction on noise and vibration. This application is successfully adapted without scarifying stability criteria related to the structural stability including excessive deformations or displacements. Three traffic operation safety limits: deck vertical acceleration, deflection of the structure, and longitudinal displacement of the slab were satisfactory.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3D
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• pp.289-294
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• 2010

It is well known that rumble strips contribute to reduce traffic accidents. The present paper provides the reduction effect of traffic accidents under specific highway geometrics after rumble strip installation. Traffic accidents on freeway sections before and after rumble strip installation are compared when conditions of the highway geometric characteristics such as horizontal, vertical geometrics are given. It is shown that rumble strips are effective under highway geometric conditions of down slopes or right curvatures. It is also shown that rumble strips are still effective with shorter length of installation.

• Korean Journal of Agricultural Science
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• v.39 no.2
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• pp.271-277
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• 2012

Dimensions, operation conditions and improvement items for round roof windows were investigated in arch shape single-span plastic greenhouse with roof vents, and natural ventilation performance was analyzed based on the ventilation theory. Diameter of round roof windows was mostly 60 cm, and chimney height projected on roof was average 30 cm. Installation space was mostly 5 to 6 m but farmhouse of 10 m and over was 16.7% also. A round roof window which has 60 cm diameter was installed to 6 m space generally and 80 cm diameter was installed to 10 m space, but correct standards did not exist. There were a lot of opinions that ventilation effect of round roof windows is fairly good and user satisfaction is generally excellent. It is problem that there is few effects in summer and that vinyl around each vent tears well and rainwater leaks, and improvement hope item required development of automatic control system. In the wind speed of 0.3 m/s, it was estimated that natural ventilation rates were 0.69, 0.55, 0.50 and 0.48 volumes per minute in case of 2, 4, 6 and 8 m installation space for round roof windows, respectively. It was analyzed that the ratio of ventilation due to buoyancy out of total ventilation were 65.2, 41.9, 29.9 and 22.8% in case of 2, 4, 6 and 8m installation space, respectively. By the round roof windows installed at space of 6 m, ventilation rate was estimated to 0.5 volumes per minute, and we can expect the increase in ventilation rate of 30%. In order to meet the recommended ventilation rate for summer season, we have to install the round roof windows at space of 1 to 2 m. However, it is difficult to apply those installation space because of falling productivity due to lower light transmittance as well as rising costs. It is estimated that the installation space of 6m is appropriate for spring or fall season. Therefore it is necessary to encourage installing the roof windows in single-span plastic greenhouses.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.14-20
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• 2009

In this paper, the time-varying failure rate to consider climate effect was extracted. Even if the same kind of equipments is estimated for extracting the time-varying failure rate, the failure rates could be different depending on external effect such as climate. With the consequence, the failure rate extracted to consider the climate effect is necessary for using the failure rate on the optimal investment plan or asset management, To consider the characteristic of climate effects(Classified into 5 categories, heavy rain, thunderbolt, strong wind, tidal waves, no character), the survey of officers charging the operation of equipment in KEPCO branch office was done. With this consequence, this paper suggest the failure rate extraction method to consider the climate effect analyzed by the survey.

• Journal of the Korean Solar Energy Society
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• v.26 no.1
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• pp.81-89
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• 2006

Building integrated photovoltaic (BIPV) system operates as a multi-functional building construction material. They not only produce electricity, but also are building integral components such as facade, roof, window and shading device. On the other hands lots of architectural considerations should be reflected such as Installation position, shading, temperature effect and so on. As PV modules function like building envelope in BIPV, combined thermal and PV performance should be simultaneously evaluated This study is on the combined thermal and PV performance evaluation of BIPV modules. The purpose of this study is to investigate a temperature effect of PV module depending on the ventilation type of PV module backside. Test cell experiment was performed to identify the thermal and power effect of PV modules. Measurement results on the correlation of temperature and power generation were obtained. Those results can be utilized for the development of optimal BIPV installation details in the very early design stage.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.11
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• pp.9-16
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• 2010

This paper examines the temperature characteristics of an Optical CT (optical current transformer) using the Faraday effect for measuring high current in a super high voltage-power apparatus. It is performed as follows by the sensor for embodying Faraday effect. $\cdot$ A single-mode optical fiber capable of maintaining a polarization state is used. $\cdot$ A light source is applied at 1310[nm] to a Laser Diode. $\cdot$ The Linear of Faraday effect to a large current is evaluated and $\cdot$ A possible application using an Optical CT was shown. An Influence of Faraday effect to the surrounding temperature measured -40~50[$^{\circ}C$], and the characteristic of the current sensitivity was reported. An application using the results of the temperature compensation system was used in order to compensate for surrounding temperatures. A possibility of applying Optical CT for electric power apparatus was advanced further. We were able to confirm that this temperature calibration method can minimize the fluctuation of the output signal depending on the temperature conditions.

• 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.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.5
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• pp.75-80
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• 2001

This paper represents the analysis and countermeasure about the causes of various trouble-examples by the noise in plants. These kinds of troubles came out the mis-operation and damage in various kinds of operating-facilities. The cause-analysis is following as: 1) the inappropriate-applications of protection devices installed to protect the noise. 2) the causes of voltage difference in separate ground systems. Therefore, To resolve the noise problems in plants, This paper proposed the two kind solutions to a problem. 1) The installation of appropriate noise protection devices and 2) The organization of equal-voltage by the common grounding system.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.81-86
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• 1999

The installation of vertical drains by means of a mandrel causes significant remolding of the subsoil, especially in the immediate vicinity of the mandrel. Thus, a zone of smear will be developed with reduced permeability and increased compressibility. This paper is mainly concerned with a field study to investigate the effect of smear due to vertical drain installation. In the present study, a field smear test was conducted to assess the extent of the smear zone around the vertical drain. The extent of the smear zone around a vertical drain was evaluated from the CPT results. CPT test was carried out to some distance around the mandrel installation. The test results revealed that a smear zone was estimated to be 3.6~5.3 times of the mandrel diameter.