• Current Photovoltaic Research
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• v.11 no.4
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• pp.134-143
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• 2023

Efforts are being made to respond to global warming. Interest in and demand for the private sector-led RE100 campaign is also increasing. Self-built solar power generation, one of the implementation tools for RE100, is not expanding. However, it can be an economical means of implementation in the long run. In this study, we intend to analyze the impact on the optimal ratio of self-solar power generation using HOMER simulation. OPR defines the optimal solar power generation ratio and looks into what changes there are in the optimal solar power ratio when self-power consumption increases and external power purchase price changes. As a result, the optimal rate of self-solar power generation has a low impact even if self-power consumption increases. As the external power unit price increases, the optimal ratio increases, and at a power unit price of 100 KRW/kWh, OPR is 24%; at 200 KRW/kWh OPR is 31%; and at 300 KRW/kWh OPR is 34%. This shows that the electricity price replaced during the life cycle has a high impact on the economic feasibility of solar power generation. However, when the external power unit price reached a certain level, the increase in OPR decreased. This shows that it is difficult for domestic companies to achieve RE100 based on the economic feasibility of solar energy alone. Therefore, efforts are needed to supply renewable energy in the public sector.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.4
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• pp.421-429
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• 1997

This study is theoretically examined the influences on the performance of diesel engine super¬charged by exhaust gas turbine with the change of excess air factor, admission ratio, total efficien¬cy of turbine and compressor, scavenging pressure ratio, and scavenging temperature. In this study, all calculations are carried out by computer, and the theoretical engine performance is com¬pared with the actual engine performance which is offered from engine manufacturer. Following results are acquired by this study. The mean effective pressure is increased with decrease of excess air factor or increase of scavenging pressure ratio. As the admission ratio or total efficiency of tur¬bine is increased, the mean effective pressure is increased but the specific fuel consumption is decreased. Mean calculation error compared with the actual engine performance is under 5 per¬cents, therefore, this calculation method can be used in the design of diesel engine.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.5
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• pp.405-415
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• 2007

The effects of recirculated exhaust gas on exhaust emissions under four kinds of nozzle tip with the different fuel consumption rates are experimentally investigated by using an once-through boiler with a FGR system. The purpose of this study is to develop the FGR control system for reducing $NO_x$ emissions in boilers. Intake and exhaust oxygen concentrations, and equivalence ratio are considered to figure out the effect of FGR rate on exhaust emissions at various fuel consumption rates. It is found that $NO_x$ emissions are markedly decreased, while soot emissions are increased owing to the drop of intake and exhaust oxygen concentrations, and the rise of equivalence ratio as FGR rates are elevated. One can also conclude that the reduction in $NO_x$ emissions is more considerably influenced by the variation of equivalence ratio due to the FGR rate than the fuel consumption rate.

• KDI Journal of Economic Policy
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• v.36 no.4
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• pp.171-205
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• 2014

This paper investigates the manner in which house prices affect macroeconomic variables through a house price channel by applying the method of Iacoviello (2005) to Korean data, and establishing a DSGE model with complementarity. This paper found that higher LTV ratio coupled with stronger complementarity results in the co-movement in both consumption and housing. For instance, the results show that when the LTV ratio and complementarity stands respectively at 50% and 0.42, an 1% rise in house prices increases consumption by 0.057%, and when the complementarity parameter increases to 0.52 with LTV remains unchanged at 50%, consumption rises by 0.047% per 1% increase in house prices. An increase in house prices leads credit constraints for borrowers to become more loose as value of a house rises as a collateral. The increase in household credit enables more consumer spending, eventually leading to increased consumption. A key link in which house prices are connected to macroeconomic variables is change in consumption. To put it simply, a rise in house prices leads to an increase in consumption, which consequently impacts the overall macro-economy. At this point, complementarity is found, in that the elasticity of intra-temporal substitution between housing and consumption is estimated at 0.42, which plays an important role in the house price channel by amplifying the effects of house prices on consumption.

• Biomedical Science Letters
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• v.30 no.1
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• pp.24-31
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• 2024

Mercury is a chemical pollutant widely present in the environment. Humans are generally exposed to mercury in the form of organic Hg (methylmercury) through the consumption of seafood. Koreans enjoy eating fish therefore blood mercury concentration is usually higher than in developed countries. By investigating blood mercury concentration according to the frequency of seafood consumption and sociodemographic factors, we aimed to identify recent trends in blood mercury concentration in Korean adults. This study was conducted using KoNEHS cycle 4 (2018~2020) from the National Institute Environmental Research Survey. The geometric mean concentration of blood mercury of the subjects was 2.959 (±1.018) ㎍/L, which was significantly higher in men than in women. It was observed that as the frequency of fish and shellfish consumption increased, the blood mercury concentration increased. In adjusted logistic regression, fish consumption was associated with 36.7% increased risk of blood mercury levels [Odds ratio, 1.367; 95% confidence interval (CI), 1.246~1.500], and shellfish consumption was associated with 26.5% increased risk of blood mercury levels [Odds ratio, 1.265; 95% confidence interval (CI), 1.134~1.410]. Blood mercury concentration was also found to increase as the socioeconomic level increased. In conclusion, the geometric mean concentration of blood mercury was increased compared to the one in the 3rd KoNEHS (2015~2017) and seafood consumption and socioeconomic level were still significantly associated with increasing blood mercury concentration in Korea. Therefore, it is necessary to encourage healthy seafood consumption habits and conduct continuous monitoring considering various factors to reduce blood mercury levels.

• Journal of Information Display
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• v.10 no.4
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• pp.164-170
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• 2009

The dependences of color gamut size and power consumption on the area ratio of the neutral and green subpixels for the RGB-LED-backlight RGBW LCD were studied, in which the red- and blue-subpixel areas are the same and represent one-quarter of the pixel aperture area. It was found that the color saturation of the RGBW LCD can be improved through the use of a smaller neutral- and green-subpixel area ratio, at the expense of higher power consumption.

• Journal of the Korean Solar Energy Society
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• v.31 no.3
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• pp.67-72
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• 2011

The aim of this study is to evaluate how much would the building energy consumption be saved by applying DSSC BIPV window which is possible to control the transmittance and express the color in the office building. For this, physical characteristics such as transmittance and reflectance, U-factor of DSSC areanalyzed and an annual energy consumption that is connected to dimming control is calculated when DSSC BIPV window is applied by alternate clear window system. As a result, It is possible to reduce the anannual energy consumption as much as4.1% by just change the clear double window system to DSSC BIPV double window system because the major factor to reduce energy consumption in the office that has much cooling load than other building is SHGC. When the thermal insulation properties of DSSC BIPV window with low-e coating and making triple window are improved, energy saving ratio is about 9%. Plus, energy saving ratio of 25~28% in lighting energy consumption is possible when the dimming control system with DSSC BIPV window is adopt.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.4
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• pp.99-109
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• 2008

As the price of traditional fossil fuels continue to increase, more people attach importance to the pollution of the environment caused by fossil fuel's burning, developing and using renewable energy resources has become a very important project all over the world. Also, the rural energy planning which is another method to improve energy utilization ratio and reduce environment pollution, is also regarded as a very effective way to reduce the energy consumption. There is a quantity of renewable energy resources and natural tribes in rural area, which is both feasible to develop the renewable energy and the regional energy planning. To carry out this, it is needs to know the area's quantity of renewable energy resources and the total energy consumption. This paper is to find out the relationship between rural energy consumption and rural conditions, and to found a energy consumption model which can conjecture the energy consumption in rural family. and the cost of rural family's energy consumption was founded to conjecture how much money dose it cost in rural family's energy consumption. The energy consumption model was concluded using the surveys of 76 families in 14 villages at the area of Chungcheongbuk-Do(province). The main factors to energy consumption was selected out which were number of family members, acreage of house, acreage of farmland and family's annual income.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2916-2921
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• 2008

This paper presents the performance and characteristics of small spark-ignited small 2-stroke engine. A single cylinder, two-stroke, air cooled 23cc SI engine for brush-cutter was used in this study. For the performance of the engine, rpm, torque, fuel consumption and lubricate oil consumption were measured, and also HC, CO, NOx emissions and excess air ratio according to throat open ratio under two lubrication method were measured and analyzed. The results showed that maximum of engine rpm is nearly same in both methods and also, torque, power is similar. exhaust emissions tend to decrease with throat open ratio.

• Korea journal of population studies
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• v.18 no.2
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• pp.115-168
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• 1995

It is a common wisdom that the long-term economic development of Korea chiefly depends not only on the steady increase of the capital formation but also on the stable increase of the national saving. And also it is a widely accepted opinion that household saving plays a significant role for the smooth supply of investment funds. For the empirical analysis on the determining factors of household saving, consumption function of the household of Korea was utilized indirectly. The reason is that consumption function is regarded as a stable function whereas saving function is considered to be an unstable function of the relevant independent variables. In order to carry out the regression process of the consumption functions, data on the family income and expenditure survey and the farm household economy survey was used. The regression result could be summarized as follows : Firstly, household income and the number of the employed in the household have the negative effect in determining the consumption ratio of the Korean households. On the other hand, ages and the educational attainment of the household heads as well as the number of the household members have the positive effect. During the early part of 21st century, the consumption ratio of the Korean households is expected to be decreased because of the increasing trend of household income, and the ever increasing number of the employed member of the household based on the increasing trend of the labor force participation rate of women and the decrease of the average size of the number of household members owing to widespread nuclear family system. On the other hand, the consumption ratio of the household of Korea is expected to be increased because of the continuous increase of the average ages of the household heads caused by the population aging phenomena and improvement of the educational attainment of the household heads. But on the whole, household saving ratio is expected to be increased owing to the secular downward trend of the consumption and therefore no significant difficulties are anticipated for the smooth provision of investment resources needed to have long-term economic progress of Korea.