• Journal of Korea Water Resources Association
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• v.49 no.1
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• pp.41-49
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• 2016

This study proposed a new drought index considering the accumulative pattern of daily rainfall, i.e., Rainfall Accumulation Drought Index (RADI). The RADI can be easily calculated at daily scale by comparing the long-term averaged cumulative rainfall to the observed cumulative rainfall for a specific duration. This study evaluated the availability of the RADI in the field of monitoring short-term and long-term droughts by investigating the spatial and temporal variability and the recurrence cycle of drought in South Korea. To present the short-term and long-term droughts, the various SPIs with different durations should be used in practice. However, the RADI can present and monitor both short-term and long-term droughts as a single index. By investigating the national average of the RADI, specific drought patterns of 20-year cycle were identified in this study. This study also proposed a five-level drought classification considering occurrence probability that would be a suitable alternative as a drought criterion for drought forecast/response.

• Korean Journal of Pharmacognosy
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• v.43 no.4
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• pp.308-315
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• 2012

Opuntia humifusa known as the Eastern prickly pear have been used as a treatment of burns, diarrhea, asthma, rheumatism, gonorrhea, and diabetes in alternative medicine. O. humifusa is widely cultivated in the middle and southern provinces of Korea and distributed in North America. The aim of this study is to investigate anti-diabetic effect of O. humifusa stem (OHS) water or 80% MeOH extract using 3T3-L1 adipocytes and db/db mice animal models. OHS 80% MeOH extract at a dose of $250{\mu}g/ml$ significantly increased the glucose uptake and lipid accumulation compared with the control in 3T3-L1 adipocytes. Blood glucose, plasma total cholesterol and triglyceride levels were significantly reduced by oral treatment of OHS 80% MeOH extract (200 mg/kg BW) for 6 weeks in db/db mice. Also, the oral treatment of OHS 80% MeOH extract slightly changed the plasma insulin and insulin resistance levels in db/db mice, but were no significance in comparison to control. Glucose transporter(GLUT)4 expressions of adipose tissue and muscle were significantly increased more than that in the control. Therefore, these results suggest that OHS 80% MeOH extract inhibits the blood glucose level through regulation of lipid profile, insulin resistance, and GLUT4 expression in db/db mice and its diabetic effect is effective more than water extract.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.5
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• pp.574-580
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• 2013

Green technology encompasses a growing group of methods and materials, from techniques for generating energy and alternative resources to non-toxic cleaning products. Green technology is expected to solve current problems in atmospheric environment such as climate changes due to green house gases and hazardous air pollutants. This paper provides a review on the status of green technology and policy guidelines in Korea as well as the green technology for air pollutants. It presents the R&D projects and future direction in atmospheric environment, and the green technology in mobile source air pollution. Emerging green technology contributes to sustainable growth and development of atmospheric environmental industry for better air quality.

• Korean Journal of Hydrosciences
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• v.4
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• pp.33-49
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• 1993

The Purpose of this study is to classify existing hysteresis models and to discuss a possibility of a new type of the hysteresis model. The existing hysteresis models are classified into three types: the interpolation model, the scaling model and the domain model, of which only domain model is to simulate hysteresis curves based on the theoretical approach, It is useful to develop a hysteresis model that requires only one branch of hysteresis curves for the model calibration because obtaining hysteresis curves by experiments is expensive and time-concept by many investigators, however their models are not successful to accurately simulate real data of Rubicon Sandy Loam and Dune Sand. There is a possibility that a new model is based on the dependent domain concept considering the weighting factor, $P_a$($\theta$), which accounts for the pore blockage effect against air entry. Conclusively, a new model where the weighting factor $P_a$($\theta$) in Model III-1 (Mualem, 1984) reduces to a known variable through an appropriate method is an alternative model which required only one branch of main curves for the model calibration.

• Ocean and Polar Research
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• v.28 no.4
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• pp.425-438
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• 2006

This study has the purpose of providing a framework for analyzing problems of institutional choice, illustrating the complex configuration of variables that must be addressed when individuals in field settings attempt to fashion rules to improve their individual and joint outcomes. The reason for presenting this complex array of variables (i.e., situational variables) as a framework rather than as a model is precisely because one cannot encompass this degree of complexity within a single model. The results of this study imply that it is important for researchers and government officials to understand that appropriators have a certain amount of ability to transform the status quo rules to the alternative rules.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.557-560
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• 2009

When we urgently need to develop and supply an alternative energy, wind power is growing with much interest because it has relative low cost of power and area of tower. To estimate the wind power resource, it is necessary to make an observation first. Although the large wind falm and resources are near coast and mountain area, the wind energy in urban area has the strong thing of direct access to power generator. In this study, we estimate the probability of wind energy above urban area using SODAR data, which is located at the top of the tall building (140m).

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.816-818
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• 2005

In this paper, we have developed an hourly operating strategy for Direct load control (DLC) considering the efficiency of DLC program and increasing the utility of DLC resource. According to the operating code for DLC, the DLC center should curtail the load for 4 hours when the control notification has been enforced. Since the above strategy may limit the participation of entities, who intend to take part in the DLC program, the new strategy to mitigate the above limitation is required. In this paper, we have developed the operating strategy of DLC program and the mechanism to apply the proposed strategy in the DLC center. The proposed strategy makes the important role from the view of guaranteing the effective alternative raising the participation and avoiding the penalty of the entities.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.7
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• pp.112-120
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• 2020

During the past decades, dramatic technology changes affected the life of billions of people around the globe. Although these changes resulted to economic benefits, mostly for the developed countries, the undiscerning development also resulted to many side effects, such as environment pollution, scarce natural resources, global warming, and an increase of the gap between "those who have" and "those who have not", among others. Also, since these developments were based on high technologies, they were not suitable for 90% of the underdeveloped countries. In this review, the possible ways of increasing the quality of life in underdeveloped countries are described, by providing adaptive solutions using appropriate technologies. Some successful applications of appropriate and intermediate technology are introduced, and the need for a new undergraduate education course of engineering design based on appropriate technology is proposed for Korea.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.498-500
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• 2009

When we urgently need to develop and supply an alternative energy, wind power is growing with much interest because it has relative low cost for generating power and small area for wind turbine. To estimate the wind power resource, it is necessary to make an observation first. Although the large wind farm and resources are near coast and mountain area, the wind energy in urban area has the strong thing of direct access to power generator. In this study, we estimate the probability of wind energy in urban mountain area using A2C (Atmospheric to CFD) model, which is used for horizontally urban scale phenomena. In the steady state results, the site C is most suitable for wind power in the point of the only wind speed. But, estimating the TKE and vertical wind shear, the site B is showing the better results than the site C.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.2
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• pp.214-220
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• 2015

Since resources of fossil fuels are limited, development of alternative energies is emphasized and research on new-regenerative energy is actively in progress worldwide. In present research, physical and chemical characteristics of mixed fuel are analyzed in detail for the different mixture rate of conventional and bio-diesel and ultrasonic irradiation time. Experimental setup consists of ultrasonic generator, vibrator, horn, and reflector. Various physical and chemical characteristics of fuel are investigated for volumetric mixture rate of bio-diesel from 0 to 100%. As results, viscosity and surface tension is increased as mixture rate of bio-diesel is increased. Also, molecular splits and reunions are increased and decreased repeatedly after some period of time as ultrasonic energy irradiation time is increased. As conclusion of experiments, Olefin rate, Branch index, and Aromatic rate are influenced by ultrasonic irradiation time.