• ETRI Journal
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• 제33권4호
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• pp.648-651
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• 2011

This letter presents a highly efficient rack-level DC power architecture combined with a node-level DC uninterruptible power supply (UPS). The proposed system can provide almost the equivalent power efficiency of a high-voltage DC data center without any change in the existing power infrastructure. The node-level DC UPS combined with a power distribution board provides high power efficiency as well as lower UPS installation costs. Implemented on a rack, the entire power system can be monitored through a network.

• Journal of Electrical Engineering and Technology
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• 제13권1호
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• pp.263-269
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• 2018

In this study, a selective inverter operation between a 2-level voltage source converter (VSC) and a 3-level T-type VSC (3LT VSC) is proposed to improve the efficiency of a 3LT VSC. The 3LT VSC topology, except for its neutral-point switches, has similar operations as that of the 2-level VSC. If an operation mode is changed according to efficiency, the efficiency can be improved because efficiencies of each methods are depending on current and MI (Modulation Index). The proposed method calculates the power losses of the two topologies and operates as the having lower losses. To calculate the losses, the switching and conduction losses based on the operation mode of each topology were analyzed. The controller determined the operation mode of the 2- or 3-level VSC based on the power loss calculated during every cycle. The validity of the proposed control scheme was investigated through simulation and experiments. The waveform and average efficiency of each method were compared.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.171-175
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• 2004

Need of a dimmer function becomes more important with increasing interest on a HDTV for home theater applications. In a conventional ac PDP, a possible method to reduce luminance of a whole panel is to reduce a total number of sustain pulses and then to change the gray level. However, the reduction of the total sustain number causes the step of luminance to be rough Moreover, it is impossible to control the luminance of the panel for a given gray level. In this paper, a simple and robust method is proposed to control linearly the luminance of whole panel by applying the asymmetric sustain pulses in the display period of the ADS driving scheme. As the range of luminance control by the proposed method is about 50% for a given gray level. Moreover, it is experimentally verified that the proposed method shows similar dynamic margin performances compare with the conventional method.

• 보건교육건강증진학회지
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• 제33권4호
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• pp.47-54
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• 2016

Objectives: The prevalence of insufficient physical activity is relatively high in the Republic of Korea and it is increasing. The national strategies to improve physical activity are essential and are suggested in this paper. Methods: National level of physical activity is compared globally by WHO statistics. Korean National Health and Nutrition Survey showed the level of physical activity. National strategies to improve physical activity were suggested referring to the other countries' strategies, public health books and Health Plan 2020. Results: Prevalence of insufficient aerobic exercise in 2010 were 33.4%, 94.8% in over and 18 years old, 11~17 years old, respectively. And it is increasing. Sufficient exercise to fit the national guidelines of physical activity were done by 15.6% of Korean older and 19 years old. Prevalence of insufficient physical activity was high in the elderly, female, adolescent, rural area and lower income. The national spread of the physical activity guidelines, primary care physicians involvement, supports for the physical activity programs, development of the evaluation protocol for the programs and environmental supports are suggested. Conclusions: The government induced various efforts to improve the level of physical activity is needed urgently.

• 한국관개배수논문집
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• 제13권2호
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• pp.236-245
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• 2006

Among a number of methodologies for developing groundwater supply to overcome drought events reported in the research community, an accurate estimation of the groundwater level is an important initial issue to provide an efficient method for operating groundwater. The primary objective of this paper is to develop an advanced prediction model for the groundwater level in the catchment area of the Ssangcheon groundwater dam using precipitation based period dividing algorithm and response surface methodology (RSM). A numerical example clearly shows that the proposed method can effectively forecast groundwater level in terms of correlation coefficient ($R^2$) in the upstream part of the Ssangcheon groundwater dam.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.288-288
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• 2008

The flux-coupling type superconducting fault current limiter(SFCL) is composed of a series transformer and superconducting unit of the YBCO thin films. The primary and secondary coils in the transformer were wound in series each other through an iron core and the YBCO thin film was connected with secondary coil in parallel. In a normal condition, the flux generated from a primary coil is cancelled out by its structure and the zero resistance of the YBCO thin films. When a fault occurs, the resistance of the YBCO thin films was generated and the fault current was limited by the SFCL. In this paper, we investigated the fault current limiting characteristics according to fault current level in the flux-coupling type SFCL. The experiment results that the fault current limiting characteristics was improved according to increase of the fault current level.

• 약학회지
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• 제33권5호
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• pp.300-307
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• 1989

Expression of transferrin gene in various organs of rat was studied using rat transferrin cDNA. The hybridization method of $[^{35}S]-labeled$ transferrin cDNA with transferrin mRNA in cytoplasmic preparations was used to measure the level of transferrin mRNA. The rat from 15-day old fetus to 21-day old postnatal were employed as an animal model. In the liver, the level of transferrin mRNA increased with increasing age. However, the level of transferrin mRNA in brain was significantly lower than that in liver and the level did not increase with age.

• 한국멀티미디어학회논문지
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• 제21권12호
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• pp.1425-1430
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• 2018

In this paper, we propose a CNN based deep learning algorithm for semantic segmentation of images. In order to improve the accuracy of semantic segmentation, we combined pixel level object classification and image level object classification. The image level object classification is used to accurately detect the characteristics of an image, and the pixel level object classification is used to indicate which object area is included in each pixel. The proposed network structure consists of three parts in total. A part for extracting the features of the image, a part for outputting the final result in the resolution size of the original image, and a part for performing the image level object classification. Loss functions exist for image level and pixel level classification, respectively. Image-level object classification uses KL-Divergence and pixel level object classification uses cross-entropy. In addition, it combines the layer of the resolution of the network extracting the features and the network of the resolution to secure the position information of the lost feature and the information of the boundary of the object due to the pooling operation.

• 복식
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• 제67권4호
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• pp.21-37
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• 2017

Fashion market in the past had a physical structure, and the supply and demand developed within that space. However, this has changed with the development of online fashion market, as it no longer requires physical space. The purpose of this study was to examine the satisfaction level of online shopping purchase based on the purchase motivation of women in their 20's. It aimed to look into how the online media affected the market, and find ways to improve the shopping malls according to the demands of the market. This study examined the effect of female students' online shopping motivation on their satisfaction with a premise that purchase motivation is related to the satisfaction level. The researched subjects were selected among female college students, and the regression analysis was done using the collected questionnaires. Results showed that economic purchase motivation, product purchase motivation, hedonic purchase motivation, and social purchase motivation had positive correlation to satisfaction level. The most influential factors to the satisfaction level were convenient purchase motivation and product purchase motivation, then social purchase motivation in shopping. Hedonic purchase and economic purchase were less influential than other factors in online shopping. Social purchase motivation factor is least influential when compared to others. As for detailed purchase motivations affecting the satisfaction level, reasonable price, latest fashion goods, interest and fun of online shopping, and the ease of shopping were important factors. The research result indicates that alternative shopping solutions can be better understood by examining the online shopping satisfaction according to purchase motivation, and improve current online shopping malls.

• 한국대기환경학회지
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• 제30권2호
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• pp.161-174
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• 2014

The methodology report '2006 IPCC Guidelines for National Greenhouse Gas Inventories' shows higher tier method can be a good practice, which uses country-specific or plant-specific data when calculating greenhouse gas emissions by country. We review the methodology report to present principles of using plant-level data and also examine examples of using plant-level data in chemical and metal industry in 20 countries for the purpose of quality improvement of national greenhouse gas inventories. We propose that Korea consider utilizing plant-level data, as reported according to 'Greenhouse gas and Energy Target Management Scheme', in the following order as a preference. First, the data can be utilized for quality control of Korea's own parameters, when Tier 2 method is adopted and bottom-up approach is not applicable. Second, both plant-level data and IPCC default data can be used together, combining Tier 1 method with Tier 3 method. Third, we can also use acquired plant-level data and country specific parameters, combining Tier 2 method with Tier 3 method. Fourth, if the plant-level data involves all categories of emissions and the data is proven to be representative, we can apply Tier 3 method. In this case, we still need to examine the data to check its reliability by a consistent framework, including appropriate quality control.