• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.1964-1970
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• 2010

A new intelligent power network (Smart Grid) that grafts some new technologies, such as the extension of the new and reproducible energy, electric motors, and electric storages, onto the regulation of green house gases according to the recent convention on climate changes has been actively promoted. As establishing such an intelligent power network, it is possible to implement a real-time rate system according to the change from the conventional single directional information transmission to the bidirectional information transmission. Such a real-time rate system can provide power during the chip rate hour by avoiding the high rate hour although customers use the same level of power through providing such real-time rate information including power generation costs. In this study, the establishment of an operating system that makes an effective use of the real-time rate system and its operation method are to be proposed.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.38-40
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• 2009

In order to achieve a gearless construction of the wind energy conversion system(WECS), a low-speed generator should be used. Of the various candidate machine types, radial-field, multi-pole, permanent magnet, synchronous machines may be used for low-speed applications. So, this paper deals with the design of direct-coupled, multi-pole radial field machines with permanent magnet(PM) excitation for wind power applications for cogging torque reduction through the determination of optimum pole arc/pitch ratio. On the basis of an equivalent magnetic circuit method(EMCM) and a space harmonic method(SHM), an initial design is performed considering restricted conditions. And then, a detailed design is made using a non-linear finite element analyses(FEA). Finally, test results concerning generating characteristics are given to confirm the validation of the design.

• Journal of Environmental Impact Assessment
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• v.22 no.4
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• pp.329-343
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• 2013

According to previous studies, the increased air temperature can lead to change of thermal stratification structure of lakes and reservoirs. The changed thermal stratification may result in alteration of materials and energy flow. The objective of this study was to predict the effect of climate change on the water temperature and stratification structure of Daecheong Reservoir, located in Geum River basin of Korea, using a three-dimensional(3D) hydrodynamic model(ELCOM). A long-term(100 years) weather data set provided by the National Institute of Meteorological Research(NIMR) was used for forcing the 3D model. The model was applied to two different hydrological conditions, dry year(2001) and normal year(2004). It means that the effect of air temperature increase was only considered. Simulation results showed that the surface water temperature of the reservoir tend to increase in the future, and the establishment of thermal stratification can occur earlier and prolonged longer. As a result of heat flux analysis, the evaporative heat loss can increase in the future than now and before. However, the convective heat loss and net long wave radiation from water surface decreased due to increased air temperature.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.6
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• pp.583-588
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• 2008

Swell data observed in the East Sea in February, 2008 were analyzed using wavelet method. The wavelet analyzed results show detailed time series variation of wave group, peak frequency and spectrum. The comparison of time averaged wavelet spectrum with fourier spectrum turn out to be very similar in terms of spectrum shape and peak frequency evolution but the peak frequency wave energy and the significant wave height show discrepancies. Wavelet analysis can detect the change of spectrum in time as well as in frequency and very efficient to study transient and irregular phenomena such as freak waves and abnormal swells in the ocean. More analysis with more wave data are needed for future application.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.1
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• pp.18-24
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• 2015

In this study, a $CO_2$ air-conditioning system was investigated with different types of electrically driven compressors, parallel flow type gas cooler, four-pass type evaporator, internal heat exchanger integrated with accumulator, and electric expansion valve. The experimental study was conducted under various operating conditions (ie., different rotational compressor speeds, air inlet temperatures and air velocity coming into heat exchangers). The experimental results showed the cooling capacity was 3.5kW at $35^{\circ}C$ ambient temperature when the vehicle was idle (ie., the worst condition for cooling off the gas cooler). In terms of performance effect of the compressor, the e-RP model had a slightly better cooling capacity and coefficient of performance than the e-GR model under the same test conditions. An experimental equation for optimum cooling-performance control was also suggested based on the results. A high-pressure control algorithm for the super critical cycle was determined to achieve both maximum cooling performance and efficient energy consumption. The results from the experimental equation coincided with those of previous experimental studies.

• Hwankyungkyoyuk
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• v.25 no.1
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• pp.89-104
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• 2012

This study analyzed content on education for sustainable development in middle school science curriculum of $6^{th}$, $7^{th}$, 2007-revised and 2009-revised. Analyses criteria were developed based on literature reviews. This study developed 8 criteria such as health, climate change, urbanization and rural development, water, biodiversity and ecosystem, energy, disaster reduction and management. The results showed that 6th middle school science curriculum has 4 criteria, $7^{th}$ has 2 criteria, 2007-revised has 8 criteria, and 2009-revised has 7 criteria. This study suggests the need for developing systemized teaching material on education for sustainable development that can be integrated in the science curriculum by pursuing the following tasks: First, the goal of education for sustainable development and its need should be stated in the science curriculum. Second, the class content, themes, objectives, teaching-learning programs on education for sustainable development should be produced. Third, within science curriculum, the content should deal with perspectives and topics, and learning goal must pursue value education.

• Journal of the Korean Society of Food Culture
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• v.11 no.5
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• pp.651-661
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• 1996

Algeria is located at the Mediterranean coast of north Africa, 90% of its population is concentrated in the coastal area which is mainly devoted to agriculture. Highland steppe and vast desert climate have determined its food culture. Long arab domination has influenced food of Algeria which has also undergone certain impact of Spanish, Turkish and French occupation. A variety of agricultural products, vegetables, fruits, spices and herbs have determined cooking method and food combination of Algeria. It use neither pork nor alcohol. Its main food consists of bread made from wheat flour and couscous cooked with semoule, Mechuwi, roast lamb and chorba, mixed soup are also typical foods of this region. For climatic reason lamb and chicken are prefered. Energy efficient method is applied to cooking through using oil for saute and water for boiling. Under european influence, Algerian salad used dressing for leaf vegetables, root and other kind vegetables were boiled. Serving with cake and cookies as dessert may possibly be the influence from the French occupation. The cake and cookie are made of wheat flour or other grain flour and take a specific form to be fried sweet with honey. Herbs and spices are widely used in cooking which are easily cultivated in household: mint, basil, rosemary, bayleaf, thyme, sage, fennel, marjoram, coriander, celery. Garlic, onion, piment, red pepper, cinammon are also widely used in an ordinary cooking. Reasonable food combination and economic cooking method could be subject of Algerian food study.

• Toxicology and Environmental Health Sciences
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• v.9 no.5
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• pp.279-282
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• 2017

Lactic acid bacteria (LAB) provide numerous beneficial effects on the host body, especially on the intestine. Two LAB strains isolated from Kimchi, Leuconostoc mesenteroides and Lactobacillus sakei, were studied for its anti-inflammatory activity in acidinduced acute colitis in mice. To induce acute colitis in model mice (C57BL/6), 3% of dextran sulfate sodium treatment was treated for 7 days. Assessment of necropsy and histopathology analysis showed that oral supplementation of both L. mesenteroides and L. sakei ameliorated the symptoms of acute colitis. Moreover, the mixture of L. meseneroides and L. sakei showed synergistic effect on colitis. The results suggest that the formulation of L. mesenteroides and L. sakei mixture could be used as an oral supplementation to decrease the inflammatory harmful environment associated with colitis.

• Korean Journal of Remote Sensing
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• v.35 no.1
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• pp.195-201
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• 2019

The Outgoing Longwave Radiation (OLR) is an important satellite-driven variable for understanding the Earth's energy budget balance. The geostationary OLR retrievals require angular and spectral integration using an empirical equation for irradiance flux-to-OLR from a regression analysis, which determines the accuracy of the narrowband satellite-based OLR. We selected homogeneous pixels which is satisfied less temporal-spatial variability of cloud, on three infrared channels (6.7, 10.8, $12.0{\mu}m$) of the first multipurpose geostationary satellite in Korea, namely the Communication, Ocean and Meteorological Satellite/Meteorological Imager (COMS/MI). Multiple regression analysis was performed to retrieve OLR with improved accuracy using selected parameters based on theoretical and physical significance. This algorithm yielded retrieval with higher accuracy than broadband-based OLR retrieval: RMSE of 10.54 to $3.81W\;m^{-2}$, and bias of -8.49 to $-0.07W\;m^{-2}$.

• Corrosion Science and Technology
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• v.18 no.1
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• pp.24-32
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• 2019

The effects of zinc coating and heat treatment on the corrosion resistance of aluminum alloys including A1100 and the modified A3003, used as heat exchanger tube were investigated in this study. The grain size of the heat-treated specimen is larger than that of the specimen without heat treatment, but the grain size did not significantly affect the corrosion behavior. The concentration of zinc was noted at 11.3 ~ 31.4 at.% for the as-received Zn-coated samples and reduced to 1.2 ~ 2.4 at.% after the heat treatment, as measured by the scanning electron microscopy (SEM) with an energy dispersive spectrometer (EDS) on the surface. The concentration of oxygen is 22 ~ 46 at.% for the zinc coated specimens while noted at 7.4 ~ 12.8 at.% for the specimens after the removal of the coating. The corrosion behavior depended largely on the concentrations of zinc, aluminum, and oxygen on the specimen surface, but not on the Mo content. The corrosion potential was high and the corrosion rate was low for a specimen with a low zinc content, a high aluminum content, and a high oxygen content.