• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.172-173
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• 2007

As the power density and switching frequency increase, thermal analysis of power electronics system becomes imperative. The thermal analysis provides valuable information on the semiconductor rating, long-term reliability. In this paper, thermal distribution of the Non Punchthrough(NPT) Insulated Gate Bipolar Transistor has been studied. For analysis of thermal distribution, we obtained experimental and simulation results by using finite element simulator, Ansys and by using photographic infrared thermometer, we compared experimental date with simulation result. and got good agreement. Also this paper provided thermal distribution of IGBT connected to heat sinks. and this results will be good information to design optimal heat sink for IGBT.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1455-1457
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• 2002

The real-time dynamic rating system(DRS) can provide the maximum ampacity within required periods, so it can help the transmission-line operation more safely and efficiently. Because the conductor temperature is the main limit of increasing rating current, conductor temperature monitoring(CTM) technology is the basic to DRS. In this paper, real-time CTM was developed for 345kV XLPE cable in tunnel and we have also compared the CTM result of this study with the result according to IEC 287 and JCS 168 thermal parameters.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.211-215
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• 2009

As entering in the time of high oil price, seriousness of an energy is on the rise and the importance of energy is growing. Especially, building energy occupying 24% of total demand of energy is expected to be possible to reduce energy demand more than other section. To reduce the building energy consumption, this study analyzes function and thermal performance of Super window by heat experimental apparatus. Super window is a 2-track low-e glazing window for high insulation efficiency. By applying the results of this experiment to building energy efficiency rating tool, this study compares energy efficiency rates depending on a region.-Jeju, South, Central. And it shows how much does Super window reduce Building energy consumption.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.59-62
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• 1993

The evaluation of the temperature of the motor in operation is necessary for smaller and lighter design of motors and for the determination of insulation class. And the evaluation of the temperature in thermal transient state is necessary for the determination of the intermittent rating and the protection from the thermal overload. The temperature can be calculated exactly by considering the loss distribution, the thermal resistances and the thermal capacities dependent on temperature. Using the detailed thermal equivalent circuit, the temperature of any local part of the motor can be evaluated. The comparison between the calculated results and the experiments is performed to verify the validity of the analysis.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.189-197
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• 2004

The thermal rating of an overhead conductor, which is the maximum allowable current, is generally calculated on the basis of heat balance equation found in IEEE P738 standard. This is given as a function of the weather conditions such as air temperature, wind speed, wind direction, and sun heat. Wind speed among such weather parameters is strongly affected on determining the line rating when it appears very low level. Therefore there may occur inaccuracy since most anemometers used in line rating monitor systems may show low resolutions and stall speed performance. In this paper, we introduce a new methodology for determining the dynamic line rating in overhead transmission lines, without using my anemometer. It was shown that wind speed can be estimated by the temperatures of 2 indirect conductors, and through experimental study, the dynamic line rating obtained by the estimated wind speed was very closely that of weather model.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.10
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• pp.426-432
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• 2006

This paper describes the concepts of Static Line Rating (SLR) and Dynamic Line Rating (DLR) and the computational methods to demonstrate them. Calculation of the line capacity needs the heat balance equation which is also used for computing the reduced tension in terms of line aging. SLR is calculated with the data from the worst condition of weather throughout the year. Even now, the utilization ratio is obtained from this SLR data in Korea. DLR is the improved method compared to SLR. A process for DLR reveals not only improved line ratings but also more accurate allowed line ratings based on line aging and real time conditions of weather. In order to reflect overhead transmission line aging in DLR, this paper proposes the method that considers the amount of decreased tension since the lines have been installed. Therefore, the continuous allowed temperature for remaining life time is newly acquired. In order to forecast DLR, this paper uses weather forecast models, and applies the concept of Thermal Overload Risk Probability (TORP). Then, the new concept of Dynamic Utilization Ratio (DUR) is defined, replacing Static Utilization Ratio (SUR). For the case study, the two main transmission lines which are responsible for the north bound power flow in the Seoul metropolitan area are chosen for computing line rating and utilization ratio. And then line rating and utilization ratio are analyzed for each transmission line, so that comparison of the present and estimated utilization ratios becomes available. Finally, this paper proves the validity of predictive DUR as the objective index, with simulations of emergency state caused by system outages, overload and so on.

• Journal of Acupuncture Research
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• v.30 no.5
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• pp.51-64
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• 2013

Objectives : This study is performed to develop the oriental medical rating scale of knee pain and to assess its validity. Methods : 250 knee pain patients completed the previously accepted rating scale of knee pain(VAS, WOMAC(pain, function, stiffness), 6 minute walk test(number of steps, distance)) and oriental medical rating scale of knee pain which was developed by Hwang et al at 2012, before and after the 6 weeks acupuncture treatment. Comparing these results, we assessed the validity of oriental medical rating scale. Results : Comparing oriental medical rating scale of knee pain before acupuncture treatment with VAS, WOMAC(pain, function, stiffness) and 6 minute walk test(number of steps, distance), oriental medical rating scale showed correlation with VAS, WOMAC(pain, function, stiffness) and showed the highest correlation with WOMAC(function). Comparing the change of oriental medical rating scale of knee pain after 6 weeks of acupuncture treatment with the change of VAS, WOMAC(pain, function, stiffness) and 6 minute walk test(number of steps, distance) after 6 weeks, change of oriental medical rating scale showed correlation with the change of VAS, WOMAC(pain, function, stiffness) and showed the highest correlation with the change of WOMAC(function). Through factor analysis of oriental medical rating scale items, 4 factors(pain, swelling, deformation of the knee, thermal sense of the knee), 17 items were extracted. Conclusions : Oriental medical rating scale of knee pain reflected the patient's pain, functional limitation and stiffness well. And oriental medical rating scale reflected the patient's functional improvement after the treatment well.

• Journal of the Korean Solar Energy Society
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• v.32 no.2
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• pp.58-63
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• 2012

As the exterior of building has been considered one of th important parts, the use of glass that is suitable to express various appearances gets raised. However, windows have 6~7times lower insulating performance than insulated walls. Lately, highly efficient windows are required as the needs for reduction of energy consumption come to the force. Therefore, Nowadays more people use cooling systems in summer, more the use of Low-E glazing is increasing. Because it is good to block Solar Radiant Energy which can cause much of heat loss while cooling system is working. This study measures U-value of the double Low-E glazing window and commonly used single Low-E glazing window. And then the effect of each window on the efficiency rating has been analyzed applying to the certification system of the building energy efficiency rating which has implemented.

• Journal of the Korean Solar Energy Society
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• v.30 no.5
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• pp.38-43
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• 2010

Enhancement of exterior's insulation performance like wall or window etc. is general way for building's energy efficient and thermal performance. But exterior's opening plan is important for minimizing the energy consumption and heat loss. In this paper, energy saving rate will be analyzed and compared considering the window area's rate and window's SC(Shading Coefficient) in a apartment with Building Energy Efficiency Rating System's evaluation tool. In the process of evaluation, energy saving rate is measured at each stage of the window area's rate from 20% to 60% every 10% term and the shading coefficient value from 1.0 to 0.6. As a result of this research, energy saving evaluation could not be measured exactly with existing evaluation tool. Accord this research, Building Energy Rating System's evaluation range is needed to be broaden for exact evaluation of energy saving rate.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.2
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• pp.49-54
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• 2013

In field of apartment housing currently, insulation technology is the most effective way because it is common to improve the thermal performance, therefore, it is contributed to energy saving as several regional insulation standards and legal mandate method. In addition, by applying of building energy efficiency rating certification system, it has inspired voluntary energy conservation commitment for the building owner or facility manager by making a plan to evaluate and verify building energy performance. However, these circumstances are not enough to acquire a grade 2 of higher information. Therefore, in this study, we analyzed the impact of building energy efficiency rating and confirmed reduction ratio compared to the standard housing on the basis of recent our nation building law when we had changed the shape of windows and wall insulation performance and shapes of housing.