• Journal of Energy Engineering
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• v.25 no.2
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• pp.94-100
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• 2016

ESS(Energy Storage System) is an important source that keeps power supply stable and utilizes electricity efficiently. For example, ESS contributes to resolve power supply imbalance, stabilize new renewable energy output and regulate frequency. ESS is predicted to be expanded to 55.9GWh of installed capacity by 2023, which is 30 times more than that of 2014. To raise competitiveness of domestic ESS industry in this increasing world market, we have disseminated load-shift ESS for continuous power supply imbalance with FR ESS, and also necessity to secure domestic track record is required. However in case of FR ESS, utility of installing thermal power plant is generally generated within 5% range of rated capacity, so that scalability of domestic market is low without dramatic increase of thermal power plant. Necessity of load-shift ESS dissemination is also decreasing effected by surplus backup power securement policy, raising demand for new dissemination model. New dissemination model is promising for $CO_2$ reduction effect in spite of intermittent output. By stabilizing new renewable energy output in connection with new renewable energy, and regulating system input timing of new renewable energy generation rate, it is prospected model for 'post-2020' regime and energy industry. This research presents a policy alternatives of REC multiplier calculation method to induce investment after outlining PV-connected ESS charge/discharge mode to reduce GHG emission, This alternative is projected to utilize GHG emission reduction methodology for 'Post-2020' regime, big issue of new energy policy.

• Journal of Korean Port Research
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• v.7 no.1
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• pp.43-58
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• 1993

There has been fast progress in economy in Korea derived by a consecutive five-year plan program for economic development started in the early 1960's. In the field of transportation, rapid changes in the technological environment of transportation and communication have brought a revolution of the transport system, of which inter-modal transportation through containerisation is typical. Because of the rapidly growing traffic volumes of cargo, especially container traffic, and lack of investment into transport infrastructure in the past, both road and railway are beyond their capacity. As a result, the public-road network has suffered a serious congestion problem. For instance, in relation to the corridor between Seoul and Pusan, today, it takes about 14 hours for the journey of container trailer through Kyongbu Expressway, for which it used to take only 7 hours in 1986. For the railway, though the congestion problem is not very serious compared with the road sector, a shortage of capacity on certain main lines has emerged as a problem as railway traffic has increased. Furthermore, the further expansion of the system in near future is difficult due to burden of higher construction the cost. Unlike these two modes, coastal shipping, which has been paid relatively less attention for commodity transport in Korea, shows no constraint in this respect. In addition, it is the most cost efficient mode of transport. This work therefore aims to make a proposal for the alternative inland transportation mode, which is to promote the coastal transport of container. Three obstructing factors for the promotion of the coastal transport are investigated and some solutions for those are suggested as follows : First, it appears to be essential to provide exclusive ports for the coastal shipping, that comply with simplification, specialization and rationalization. The optimum size of berths on the exclusive ports in Pusan port is estimated as 16-20. We found that it needs periodical study and publicity on the advantages from the adoption of the coastal mode. Inducing competition in the coastal shipping market is also necessary. For the supply of the fleet in the coastal shipping, chartering of the surplus ships in the oversea shipping is found to be more desirable than new shipbuilding. Second, to solve the fragmentation of the companies which wish to participate in the coastal transport, government has to implement the subsidy policy. The encouragement of participation of the shipping lines engaging in Korea-Japan run and Korea-East South Asia run, into coastal shipping also needs to be considered cautiously. Third, simplification of the document for entry in ports is needed for rational coastal shipping management. We can use B/L (Bill of Lading) for coastal shipping as a prerequisite to get the indemnity by P & I Club. The reduction of the government controls on entering and leaving the ports also needs.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.5
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• pp.344-355
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• 2003

Korea is one of those countries that have very high usage rates of chemical fertilizers per unit area of cropland. To reduce the fertilizer application rate, a variety of agricultural polices has been introduced since the 1990s. In this study, fertilizer usage was surveyed on the farm base throughout the country in 1999, and the data were compared with those of 1992. Organic fertilizer application rates were decreased in most cereal crops with time pass, but maintained similar levels in vegetables grown in plastic-film houses and in upland soils. Chemical fertilizer application rates were decreased in most of the cereal crops and vegetables surveyed; however, this reduction was concentrated in phosphate and potassium usage, but not in nitrogen. In spite of this decrease, the fertilizer application levels to most crops were maintained at levels much higher than recommended. In the nutrient balance, which was calculated from the difference between input (chemical and organic fertilizers) and output (agricultural products), the nitrogen nutrient surplus did not decrease; however, phosphate and potassium decreased by 21% and 13%, respectively, in 1999 compared with 1992. To reduce fertilizer utilization and to conserve environment, further reduction of fertilizer application is essential.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.5
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• pp.272-279
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• 2003

This study was performed to develop a more rapid and simple nutrient diagnosis method of plants than the conventional leaf analysis method. Cucumber (Cucumis sativus L. cv. jangil banbaek) was planted in the mixed media produced by mixing perlite and rock wool at 1:1 (v/v) ratio. The Yamazakki nutrient solution for cucumber was supplied to the media using micro-drip irrigation system. Experimental plots were consisted of no fertilization, deficient fertilization, adequate fertilization, and surplus fertilization for N, P and K. Specific color difference sensor value (SCDSV) measured by chlorophyll meter was closely related to total-N concentration in leaves measured by the conventional method. Nitrate, $PO_4$ and K concentration in petiole sap measured by test strips showed a significant relationship with total-N, P and K concentration in leaves. Linear regression equations between $NO_3$, $PO_4$ and K concentration in petiole sap and total-N, P and K concentration in the leaves were prepared. Optimum levels of $NO_{3}$, $PO_{4}$ and K in petiole sap were obtained by plugging the optimum concentrations of total-N, P and K in the leaves by other researchers into the equations. In conclusion, the SCDSV measured by chlorophyll meter and the concentration of $NO_3$, P and K in petiole sap measured by the test strips would be suitable for rapid estimation of plant nutrient status.

• Journal of Convergence for Information Technology
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• v.9 no.11
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• pp.103-109
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• 2019

The purpose of this study is to examine various existing models that analyze the economic value of meteorological information, to present a new analysis model, a market model, and to quantitatively analyze the economic value of meteorological information in the Korean service industry using the market model. The research method of this paper will basically use empirical analysis along with the theoretical approach to critically examine the existing analytical model of economic value of meteorological information and to suggest a new analytical model. The analysis results are as follows. Theoretically, the marginal cost of firms is reduced by providing the amount of weather information, and social welfare is increased by the increase of consumer and producer surplus. In this paper, the marginal cost of 1% increase in the amount of weather information decreases by 0.101% and the increase in social welfare increases by 1,247billion Won in 2017. On the other hand, in the accommodation and restaurant sectors, the marginal cost due to a 1% increase in weather information decreased by 0.218%, and the social welfare increase increased by 308billion Won in 2017.

• Korean Journal of Plant Resources
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• v.32 no.5
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• pp.499-508
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• 2019

The study was carried out to investigate growth of 48.6-L pot-cultivated 1-year-old 'Fuji'/M.9 apple trees depending on different levels of nitrogen concentration. While rise in tree growth was paralleled with increase of nitrogen concentration, more than 32 mM of nitrogen rather restrained tree growth. In particular, growth of 16 mM of nitrogen treated trees was satisfied with criteria for production of high-quality pot-cultivated nursery stocks. Although mineral contents of leaves were higher in 8 and 16 mM nitrogen treatments than commonly recommended mineral contents in apple orchards, such somewhat surplus minerals could be helpful for tree growth after transplanting to apple orchards. In addition, our result indicated that soils of 8 and 16 mM of nitrogen treated pots met appropriate criteria for soil chemical property of apple orchards. Thus, in the light of tree growth, mineral contents of leaves, and soil chemical property in the pots, 16 mM of nitrogen treatment is considered to be suitable for production of 1-year-old 'Fuji'/M.9 apple potted trees.

• Economic and Environmental Geology
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• v.54 no.5
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• pp.573-580
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• 2021

This study analyzed the induced effects of the aggregate and stone sectors using the industry association table. First, the added value of the aggregate and stone sectors was summarized, and then the intermediate input structure and induced effect were analyzed. In terms of value-added structure, aggregate and stone showed a higher employee remuneration rate compared to the manufacturing industry, and a higher rate of operating surplus compared to other mining industries. The intermediate input structure summarizes the sector using aggregate and stone products as intermediate inputs and their input ratio. The proportion of the intermediate element input structure was confirmed. In addition, the main input sectors of ready-mixed concrete, the largest consumer of aggregate and stone, are also summarized. The production-inducing effect of aggregate and stone showed a higher influence coefficient than the sensitivity coefficient, confirming that they had a relatively large rear chain effect. The production inducement effect was reviewed by reconstructing the industry association table, and it was found to show a relative superiority in the influence coefficient, similar to the results derived according to the provisional classification of the Bank of Korea.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.141-149
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• 2021

This study investigated the effect of accounting information on dividend policy as a measure of corporate conservatism from the perspective of the internal accounting management system. The verification is based on a sample of 543 companies listed on securities (excluding KOSDAQ and financial industry) among the Bank of Korea (2019) 「2018 Corporate Management Analysis」 and company analysis of the Korea Productivity Center (financial data disclosed as listed companies as a December settlement company) was composed. Using SPSS 22, empirical analysis was conducted using exploratory factor analysis and regression analysis. The first is the verification related to corporate conservatism and the role of dividend policy, and it is verification of whether internal accounting management influences financial decision-making. Second, if internal accounting management exists, it is a verification of how conservatism and investment policies (in-house reserve, debt borrowing, capital increase, dividends, etc.) affect the corporate value according to accounting information. As a result, from the perspective of the internal accounting management system, it was found that among the variables of accounting information, profitability can have a positive effect on corporate conservatism and dividend policy as a corporate valuation method of reinvestment. In addition, it has been proven that corporate conservatism has an effect on profitability-to-value through capital accumulation and reinvestment such as surplus and internal reserves. In the future, we will study and discuss the complementarity of corporate conservatism and dividend policy in relation to governance structure and improvement of the internal accounting management system.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.2
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• pp.116-121
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• 2019

In order to evaluating applicability of RAP (recycled aggregate powder) in mortar, in this study, physical and mechanical tests was carried out. Material characteristics of recycled aggregate and RAP were evaluated and the mechanical properties of mortar replaced with RAP were analyzed. Test result of sieve analysis showed that as the milling time increased the fineness modulus was decreased and the distribution of 0.6 mm particle size was found to increase. The fluidity of mortar mixture substituted with RAP tended to increase than Plain mixture. It was result that the increasing fluidity was affected by unreacted surplus water in the mortar as the binder was replaced with RAP. From the compressive strength result of the mortar subjected to RAP, it was found that the RAP was able to replace up to about 10% of unit binder weight although the compressive strength of mortar was decreased as the RAP replacement increased. From the above study, it can be concluded that the physical properties of RAP satisfied the quality standard of aggregate for replacement with fine aggregate. Moreover, in case of the RAP was replaced up to 10% of unit cement weight, it was able to be possible to improve fluidity and compressive strength of mortar.

• Plant Journal
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• v.14 no.4
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• pp.39-47
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• 2018

In this research, when the output of the standard coal-fired thermal power plant operating continuously at the rated output of 500 MW is changed to operate at 300 to 500 MW, the amount of sulfur oxide produced and the amount of sulfur oxide in the absorption tower of desulfurization equipment and proposed an extra liquid to gas ratio improvement inversely proportional to the output. In order to calibrate the combustion efficiency at low power, the ratio of sulfur oxides relative to the amount of combustion gas is increased as the excess air ratio is increased. When the concentration of sulfur oxide at the inlet of the desulfurization absorber was changed from 300 to 500 ppm along with the output fluctuation. The liquid to gas ratio of limestone slurry and combustion gas was changed from 10.99 to 16.27. Therefore, if the concentration of sulfur oxides with output of 300 MW is x, The following correlation equation is recommended for the minimum required flow rate of slurry for the reduction of surplus energy due to the increase of the liquid weight at low load. $y1[m^3/sec]=0.11x+3.74$