• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.260-264
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• 2005

Effective use of water resources has become a social problem because the deficit of water comes from population growth and Industrial development. Therefore, the conjunctive operation of surface water and groundwater will become an alternative. Groundwater has many advantages for the evaporation and effect of rainfall compared with surface water. Although the available amount of groundwater is small, groundwater dam can be used complementarily because of the sustainable supply of water. A calculating technique of the optimal amount of water resources by the groundwater dam was developed. A pilot site was selected to assess the optial amount of groungwater for the designed groungwater dam. If the developed technique is more refined by the measured data, the groundwater dam will become a good alternative to develope the water resources in the water deficit area.

• Journal of Korea Multimedia Society
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• v.18 no.8
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• pp.915-924
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• 2015

With growing popularity of cloud computing services, users can more easily manage massive amount of data by outsourcing them to the cloud, or more efficiently analyse large amount of data by leveraging IT infrastructure provided by the cloud. This, however, brings the security concerns of sensitive data. To provide data security, it is essential to encrypt sensitive data before uploading it to cloud computing services. Although data encryption helps provide data security, it negatively affects the performance of massive data analytics because it forbids the use of index and mathematical operation on encrypted data. Thus, in this paper, we propose a novel algorithm which enables to efficiently process a large amount of encrypted data. In particular, we propose a novel top-k processing algorithm on the massive amount of encrypted data in the cloud computing environments, and verify the performance of the proposed approach with real data experiments.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.448-451
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• 2002

The possibility of using polypyrrole as a drug delivery system(DDS) has been studied using indicate (Phenol red) and substance with therapeutic activity(Sodium salicylate). In aqueous solution, negative potential is applied to polypyrrole then anion(with therapeutic activity) of sodium salicylate is released by redox processes of polypyrrole. The release amount of anionic drugs from polypyrrole is measured by UV-visible spectrometer which can measure UV-absorbance of materials. Electrode area that use for release amount measurement is$50mm^{2}(5{\times}10mm)$,and thickness of polypyrrole membrane is $15{\mu}m$. DC 1V applied in saline solution, the release amount according to time increased gradually. In various electrode area, release amount of anionic drug is directly to electrode area.

• International Journal of Human Ecology
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• v.6 no.2
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• pp.37-49
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• 2005

This paper gives special attention to the changes of time use patterns of the German population for eating and drinking as well as for household work. It especially examines the changes in time use for meals eaten at home and away from home as well as the division of labour for nutrition provision activities between men and women. The presented results originated from two time budget surveys conducted in Germany in 1991/92 and 2001/02. In a secondary analysis time use patterns for eating and drinking and nutrition provision activities were examined on a base of a representative sample of 12600 private households. Surprisingly the amount of time spent on eating and drinking increased over the period. More Germans ate away from home at least once a day, whereas meals at home were still dominant. Moreover comparisons over time revealed that the share in household and food provisioning work has narrowed between men and women, especially in households with both partners being employed. Overall the analysis shows that time use data allow general statements regarding the amount and changes of time spent on daily eating, household work and especially food provision activities. The extent of women's employment has shown to be most decisive for an equal division of household work between gender. To be able to better interpret the results and to understand the consequences for family life, it is necessary to complement time use data with qualitative interviews to gain comprehensive insight into peoples nutrition goals, motives and barriers of action.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.1530-1535
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• 2011

Heat radiation of LED luminaires has risen a problem when applied indoor. LEDs can save energy with higher efficacy than other light sources. However, their heat radiation may increase power consumption for air-conditioning. Therefore, this paper carried out a comparative analysis on the amount of heat radiation for MR16, E26 bulb, and down-light which will be replaced to LED luminaires. Heat amount of LED-MR16 and LED-downlight was 48% and 87.5% lower than that of conventional lamps, halogen MR16 and E26 CFL, respectively. Consequently, the heat amount and indoor temperature were proportional to the power consumption of luminaire. Therefore, the use of LED luminaire can reduce the amount of heat radiation as well as power consumption.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.664-667
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• 2004

This paper is aimed at analyzing the soil erosion hazard zone in farm land. RUSLE was used for an analysis of soil erosion amount, and for the spatial data of basin, soil erosion amount was calculated by extracting the respect topography space related factors of RUSLE using DEM, Landuse, Soil map as base map. As a result of analysis on the calculated soil erosion amount according to land use type, it was analyzed that the most soil erosion occurred in orchard area, i.e., 40.08ton/ha/yr at average. It was classified into 5 classes depending on the calculated soil erosion amount. of which Class V was decided as soil erosion hazard zone, and for this area, 72.5ha or so, $2.4\%$ of the entire farm land was assessed as erosion hazard zone.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.65-73
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• 2007

The use of an Exhaust Gas Recirculation(EGR) for a diesel engine with variable geometry turbocharger(VGT) has confronted how to obtain the amount of EGR for NOx reduction requirement at wide operating range and less side effect. Through a combined effort of modeling(wave action simulation) and experiment, an investigation into the effect of EGR area ratio and pipe length on EGR characteristics of common rail diesel engine with VGT has been performed. For accurate computation, calibration of constants involved in empirical and semi-empirical correlations has been performed at a specific operating point, before of its use for engine simulation. From the results of this study, it was found that EGR rate is sharply increased with increasing EGR area ratio until area ratio of 0.3. However, the effect of EGR area ratio on EGR rate is negligible beyond this criteria. This study also investigates the effect of EGR pipe length on a EGR amount and pulsating flow characteristics at EGR junction. The results showed that the longer EGR pipe length, the lower EGR amount was achieved due to the flow loss resulting in lower amplitude of pressure wave.

• KIEAE Journal
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• v.8 no.1
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• pp.81-86
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• 2008

Due to the recent environmental problems, lots of studies on the solutions to reduce the environmental pollutions are on the way. In the field of construction, concrete that we are currently consuming approximately 1 ton each year is the most common and cheap building material. We must cut down on this preoccupied use of this material and develop an alternative material as recommended by the late environmental standards. In this regard, this study propose the 'yellow soil' as the main substance that composes the final state, 'yellow soil concrete'. This study also aims to analyze the physical and chemical performances of this concrete mixed with the yellow soil by comparing it with the cement and assesses the possibility of its application to the cement. The results of the experiment shows that, assuming the solidity of the cement concrete to be around $210kg/cm^2$ (20.58MPa), the solidity of the yellow soil combined material may be around 45%~55% in terms of the range of W/B use, 200 to 400 in the per unit fission amount and less than 2% in the addition proportion of admixing agents. But the scope of the optimal concoction amount of the yellow soil concrete should better be limited as following. 40% to 50% in W/B, 300 to 400 in the per unit fission amount and less than 2% in the addition of admixing agents.

• Korean Management Science Review
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• v.27 no.2
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• pp.21-29
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• 2010

We consider an economic approach for spectrum operations in mobile networks. We present the investment function of base stations according to the number of FAs assuming the linearity of cell splitting. We show that there is an economic amount of spectrum which corresponds to the optimal number of FAs that minimizes the investment. We analyze the impact of the cost structure and the traffic distribution in base stations on the economic amount of spectrum. This paper is applicable to an economic spectrum operation for mobile operators. In addition, the national regulatory authority can use the economic amount of spectrum as the minimal amount for spectrum allocation.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.126-131
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• 2008

The large buildings in Korea usually use the generators to control the peak load of electronic consumption during the summer. It is necessary that these generators emit carbon dioxide, since they use gas or gasoline for their fuel. This study is to analyze the data of electronic consumption and operation of the generators at COEX, one of the representative complex building clusters in Korea, and to compare to the amount of carbon dioxide emitted per 1kWh from the domestic power plant by analogizing the frequency of using the generator during the summer and the amount of fuel consumption by the capacity of the generator and estimating the amount of carbon dioxide emitted from the generator.