• Journal of Energy Engineering
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• v.23 no.3
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• pp.125-131
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• 2014

In order to increase landfill gas (LFG) production with food waste leachate, this study was confirmed to be acidogenetic conditions for landfill site injection. Thereby, it was conducted for acidogenetic treatments to determine the decrease in viscosity and VFA production. After acidogenesis treatments, solubility of food waste leachate increased approximately 15%, and as a result, UASB and CSTR were similar by reactor type using the change of retention time. Based on the result of the change in viscosity by reactor type, efficiency of UASB showed approximately 11.38% of higher decrease in viscosity as $76.95{\pm}3.27%$ vs. CSTR. Also, VFA production showed the higher increase of 2.01 times (UASB) and 1.76 times (CSTR) respectively at the point of increasing retention time from 3 to 5 days. From the above results, efficiency of UASB in a reactor was relatively higher because large molecular lead to longer retention time than small molecular due to having screen effect in the fixed media.

• Journal of Energy Engineering
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• v.24 no.3
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• pp.82-88
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• 2015

After a reheating furnace installation, the modification of the size and the heat capacity is very difficult. Therefore, the development of design package tool is required for the computation on the correct specifications before the design and the installation. Prior to development of the design tool, a module that calculates the amount of heat loss of each part according to the specifications for determining the thermal efficiency of a continuous heating furnace was developed and applied to the oxy-fuel industrial furnace. Through this, the effects of fuel type, oxygen fraction and recirculation on the efficiency of the furnace of which the output is 110Ton/hour were analyzed. In oxy-fuel combustion condition, the efficiency was 15% higher than air combustion conditions. With the using COG(Coke Oven Gas) instead of LNG, the efficiency was slightly increased. In the air combustion condition, the efficiency was increased about 33% with the preheated air. But, in oxy-fuel condition, the amount of exhaust gas was reduced, so the efficiency was increased about 7%.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.5
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• pp.463-472
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• 2015

Solar radiation data are important data that can be used as basic research data in diverse areas. In particular, solar radiation data are essential for diverse studies that have been recently conducted in South Korea including those for new and renewable energy resource map making and crop yield forecasting. So purpose of this study is modification of Heliosat-II method to estimate solar irradiance in Korea by using COMS-MI imagery. For this purpose, in this study, errors appearing in ground albedo images were corrected through linear transformation. And method of producing background albedo map which is used in Heliosat-II method is modified to get more finely tuned one. Through the study, ground albedo correction could be successfully performed and background albedo maps could be successfully derived. Lastly, In this study, solar irradiance was estimated by using modified Heliostat-II method. And it was compared with actually measured values to verify the accuracy of the methods. Accuracy of estimated solar irradiance was 30.8% RMSE(%). And this accuracy level means that solar irradiance was estimated on 10% higher level than previous Heliosat-II method.

• Journal of KIISE:Software and Applications
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• v.41 no.7
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• pp.481-491
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• 2014

The power production using renewable energy is more important because of a limited amount of fossil fuel and the problem of global warming. A concentrative photovoltaic system comes into the spotlight with high energy production, since the rate of power production using solar energy is proliferated. These systems, however, need to sophisticated tracking methods to give the high power production. In this paper, we propose a hierarchical tracking system using modular Bayesian networks and a naive Bayes classifier. The Bayesian networks can respond flexibly in uncertain situations and can be designed by domain knowledge even when the data are not enough. Bayesian network modules infer the weather states which are classified into nine classes. Then, naive Bayes classifier selects the most effective method considering inferred weather states and the system makes a decision using the rules. We collected real weather data for the experiments and the average accuracy of the proposed method is 93.9%. In addition, comparing the photovoltaic efficiency with the pinhole camera system results in improved performance of about 16.58%.

• Journal of the Korean Society for Marine Environment & Energy
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• v.7 no.1
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• pp.35-41
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• 2004

The yeongok stream originates at the natural park, Mt. O-dae and flows to the East Sea of korea, normally maintaining I or II grade of water quality and its average water flux is 352,100 ㎥/d. However, the typhoon 'Rusa', which occured on 31 August 2002, changed its watercourse and configuration, and the ecosystem was deeply damaged. Moreover, the hydrological characteristics were once more transformed, and the ecosystem was secondarily damaged during repair-work of destroyed bridges and elevations. After the flood disaster, the species diversity diminished 17% for attached diatom and 44% for aquatic animals. However, the earth and sand, dug from river bed during intensive repair-work throughout the entire stream, made diversity drop to 32% for the diatom and the aquatic animals were wiped out. Especially, fishes were totally destroyed except for some species such as Moroco oxycephalus in the upper stream. The yeongok stream has little contamination source and short water residence time due to the short length and rapid slope, and consequently a temporary deterioration of water quality caused by repair-work may be rapidly recovered, but it needs a long time to restore the damaged ecosystem.

• Journal of Plant Biotechnology
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• v.38 no.4
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• pp.241-250
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• 2011

The most part of vegetable oils is accumulated as storage lipid, triacylglycerol (TAG) in seed and used as energy source when seed is germinated. It is also used as essential fatty acids and energy source for human and animal. Recently, vegetable oils have been more and more an important resource because of the increasing demand of vegetable oils for cooking and industrial uses for bio-diesel and industrial feedstock. In order to increase vegetable oils using biotechnology, over-expressing or repressing the regulatory genes involved in the flow of carbon into lipid biosynthesis is critical during seed development. In this review, we described candidate genes may influence oil amount and investigate their potential for oil increase. Genes involved in the regulation from biosynthesis of fatty acids to the accumulation oils in seed can be classified as follows: First, genes play a role for synthesis precursor molecules for TAG. Second, genes participate in fatty acid biosynthesis and TAG assembly. Lastly, genes encodes transcription factors involved in seed maturation and accumulation of seed oil. Because factors/genes determining oil quantity in seed is complex as mentioned, recently regulation of transcription factors is being considered more favorable approach than manipulate multiple genes for increasing oil in transgenic plants. However, it should be figured out the problem that bad agricultural traits induced by the overexpression of transcription factor gene.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.6
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• pp.513-520
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• 1991

The objective of experiment was to investigate the effects of seeding rate on forage yield and feed value, and to clarify the optimum seeding rate of rye in middle west area when cultured in paddy field. The field experiment treated with 5 levels of seeding rate was carried out at Yesan area in 1989. The plant height and the number of tillers per m' were increased but the dry matter rate was decreased as seeding rate increased. The fresh and dry weights of rye plant were increased as seeding rate increased. The highest yield was obtained from the harvest of May 15 and 25 in Yesan area. The TDN content and RFV were decreased by the increased seeding rate and delayed cutting date. The highest TDN yield was obtained from the seeding rate of 18kg/l0a and the next highest yield was obtained from the 23kg and 28kg/l0a seeding rate. The content of ENE, NEL, NEM, and NEG was decreased by the increased seeding rate and delayed cutting date. The highest ENE and NEL yields were obtained from the seeding rate of 23kg/l0a and May 15 harvest. The highest NEM and NEG yields were obtained from the seeding rates of 18kg/l0a and May 15 harvest, and of 18-28kg/l0a and May 5 harvest, respectively.

• Environmental and Resource Economics Review
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• v.21 no.1
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• pp.175-210
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• 2012

As London and post-Koyto protocols presumably affect emission of organic waste in Korea in 2012, appropriate treatment of organic waste becomes very important. Organic wastes are regarded as non-point pollutants. It has been criticized that direct emission charges on the emission of non-point pollutants are not effective due to the high uncertainty in the relationship between pollution sources and pollution levels. This study suggests indirect emission charges on production of livestocks or consumption on foods. Furthermore, it is assumed that revenue from the emission charges will be recycled to support biogas production. Biogas can be fueled to produce energy. In order to evaluate potential economic and environmental impacts of recycling the indirect emission charges on organic wastes, a static CGE model was developed. Simulation results of emission charges on the production of livestock show that livestock, agriculture, and food industry will confront relatively high burden while emission charges on consumption of food will affect more broadly and consumers will suffer more. Production charge on livestock sector will lead to higher reduction in GDP and total expenditure relative to the consumption charge. GHGs reduction effect was higher for the consumption charge relative to the production charge. Synthetically, consumption charge on food sector is more desirable as an alternative charge for the emission of organic wastes.

• Korean Journal of Organic Agriculture
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• v.20 no.4
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• pp.503-518
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• 2012

Korean type of no-tillage cultivation method which was applied on this study used the ridge and the furrow and constantly recycling them as it was suitable for Korea's weather and farming conditions. This no-tillage cultivation was reported to have little negative impact such as reduction of production (Kwon et al., 1997). In addition, it was found to have a lot of benefits as it requires less agro-materials and energy costs as well as shortened working hours because tillage operation is not needed. (Yang et al., 2012). According to an analysis, no-tillage cultivation can reduce greenhouse gas emissions by $344.7kgCO^2$ (58%) in every 10a ($1,000m^2$) compared to ordinary pepper farming technique (Korea averages). Direct-indirect reduction effects from using fertilizer and using less amount of energy were 92% and 44% respectively both of which can be considered very high. Besides the direct effects of no-tillage cultivation, soil management using no-tillage technique raises carbon sequestration effect on soil as time goes on (West & Marland, 2002), that is why the technique is expected to have constant carbon emission reduction effect. For theses reasons, distribution and expansion of Korean type no-tillage cultivation are expected to play a role as major agro-green technologies for achieving our goal of reducing greenhouse gas emissions in agricultural sector.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.3
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• pp.169-174
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• 1995

To investigate the effects of nitrogen(N) fertilization levels on the dry matter(DM) yield, nutrition yield, and N efficiency of forages in mixed sward of alfalfa-grasses, a field experiment arranged by randomized complete block design with five treatments(0, 70, 140, 210 and 280kg N/ha) was conducted at Livestock Experiment Station in Suwon, September, 1990 to February, 1993. During two years, average DM yields of forage increased as N fertilization level was increased, but no significant difference was found between DM 10,266kg of N 210kgha and DM 10,845kg of N 280kgha. Crude protein and energy productivity of forages increased as N fertilization level was increased, and the increasing degree was highest between N 140kg and 210kg/ha fertilization. With increasing N fertilization, mineral contents tended to decrease in P and K/Ca+ Mg equivalent ratios, to increase in Mg, but not to be regular in the other elements. Efficiency of N was highest at N 210kg/ha fertilization, which produced DM 21.6kg, net energy lactation 129.3 MJ, starch equivalent 12.3kStE and total digestible nutrients 14.5kg per Ikg N.