• Korean Journal of Applied Biomechanics
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• v.30 no.4
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• pp.285-291
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• 2020

Objective: Shoes midsole are crucial for reducing impact forces on the lower extremity when someone is running. Previous studies report that the cushioning of running shoes make it possible to use less muscular energies. However, the well cushioned shoes result in energy loss as the shoe midsole is compressed. Cushioning reduces the load on the body, it also results in the use of more muscle energy to create propulsion force. The purpose of this study was to investigate the effect of the difference of shoe hardness & resilience on the running. Method: Shoes midsole are crucial for reducing impact forces on the lower extremity when someone is running. Previous studies report that the cushioning of running shoes make it possible to use less muscular energies. However, the well cushioned shoes result in energy loss as the shoe midsole is compressed. Cushioning reduces the load on the body, it also results in the use of more muscle energy to create propulsion force. The purpose of this study was to investigate the effect of the difference of shoe hardness & resilience on the running. Results: In vastus lateralis muscle Activation, Type 55 were significantly higher for Type 50 and X (p=0.019, p=0.045). In Gluteus Maximus muscle activation, Type 55 was significantly lower for type 50 (p=0.005). In loading late, Type 55 and X were significantly higher for type 45 (p=0.008, p=0.006). Conclusion: The components of a shoe are very complex, and there can be many differences in manufacturing as well. Although some differences can be found in the biomechanical variables of the high elastic midsole, it is difficult to interpret the performance enhancement and injury prevention.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.6
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• pp.121-128
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• 2019

There is a big move to build zero-energy buildings in the form of passive houses that reduce energy waste worldwide. Korea has set a goal of reducing its greenhouse gas emissions by 37% by 2030 through the activation of green buildings, such as strengthening the energy levels of new buildings and improving the energy efficiency of existing buildings. The use of insulation with high insulation performance is one of the key technologies to realize this, and vacuum insulation is the next generation insulation that blocks the energy flow of the building. In this study, we measured the bonding structure of dry and wet processing glass fiber core materials and compared the insulation performance of vacuum insulation panel. In addition, the insulation performance of vacuum insulation panel was measured according to the thickness of the laminated core. It can be confirmed that the lamination structure of the core and the lamination thickness are important factors for the heat insulating performance of the vacuum insulating panel.

• Journal of Korea Trade
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• v.26 no.1
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• pp.1-19
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• 2022

Purpose - This paper analyzes the economic and non-economic factors that contribute to environmental sustainability by reducing CO₂ emissions, based on G20 panel data. Design/methodology - We conduct a comparative analysis of advanced and developing economies during 1995-2016. To examine the impact, an environmental Kuznets curve (EKC) model was employed, incorporating additional explanatory variables such as internet use, renewable energy, and services trade. Findings - The empirical findings show the existence of an inverted U-shaped EKC phenomenon between GDP per capita and CO₂ emissions in G20 economies, with the turning point at a per capita GDP level of US$ 38,340. Moreover, an inverted U-shape relation exists between internet use and CO₂ emissions, with the turning point at a 44% internet use rate. The comparative analysis show that the inverted U-shape curve only exits in advanced economies, with turning points of US$ 42,356 per capita GDP and 27% internet use rate, respectively. Renewable energy and services trade have a greater negative impact on CO₂ emissions in advanced economies than in developing economies. Originality/value - Renewable energy and services trade have a greater negative impact on CO₂ emissions in advanced economies than in developing economies. Overall, the results suggest the role of internet use, renewable energy and services trade in sustainable development in G20 countries.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.1
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• pp.130-136
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• 2011

Methane is known to be one of the major greenhouse gases. On a global scale, livestock farming may contribute 18% of total greenhouse gas emissions. Though methane contribution is less than 2% of all the factors leading to global warming, it plays an important role because it is 21 times more effective than carbon dioxide. Methane emission is a direct result of the fermentation process performed by ruminal microorganisms and, in particular, the archael methanogens. Reducing methane emission would benefit both ruminant production and the environment. Methane generation can be reduced by electron-sink metabolic pathways to dispose of the reducing moieties. An alternative way for methane control in the rumen is to apply inhibitors against methanogens. Generating methane from manure has considerable merit because it appears to offer at least a partial solution to two pressing problems-environmental crisis and energy shortage. An obvious benefit from methane production is the energy value of the gas itself. Control of methane emission by rumen microbes in Korea has mainly been focused on application of various chemicals, such as BES and PMDI, that inhibit the growth and activity of methanogens in the rumen. Alternatives were to apply long-chain polyunsaturated fatty acids and oils with or without organic acids (malate and fumarate). The results for trials with methane reducing agents and the situation of biogas production industries and a typical biogas plant in Korea will be introduced here.

• KIEAE Journal
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• v.14 no.2
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• pp.11-19
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• 2014

Building energy consumption takes up almost 25% of the total energy consumption. Therefore, diversified ways, such as improving wall and window insulation, have been considered to reduce building energy consumption. Recently, green roof system has been explored as an effective alternative for dealing with reducing heating and cooling energy, thermal island effect and improving water quality. However, recent studies regarding a green roof system have only focused on building energy reduction without considering the applied usage, location, and story of the green roof system. Therefore, this study pays attention to the heating and cooling energy in relation to the applied usage, location, and story of a green roof system for investigating its impact on energy reduction. The result of simulations show that the reduction in heating energy consumption is higher when applied to Cherwon-gun province which has a continental climate condition, compared to the city of Busan that is distinguished by its warm climate. Cooling energy saving turns out to be higher when the green roof system is applied to Busan in comparison with Cherwon. As for the applied usage or function of the building, residential space acquires the highest heating and cooling energy saving effect rather than commerce, educational or office space because of HVAC's running time based on usage. When it comes to the story of the green roof, both heating and cooling energy saving become the highest when the green roof is applied to single-storied buildings. The reason is that single story building is affected by the ground largely. Generally, the variations of heating energy consumption are larger than the cooling energy consumption. The outcome of the simulations, when a green roof system is applied, indicates that the energy consumption reduction rate is dynamically responding to the applied usage, location, and story. Therefore, these factors should be counted closely for maximizing the reduction of energy consumption through green roof systems.

• Journal of the Economic Geographical Society of Korea
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• v.16 no.2
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• pp.149-166
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• 2013

The purpose of this study is to analyze the regional disparity and its determinants of $CO_2$ emission from the residential energy consumption in China. This study examines factors that affect the $CO_2$ emission per capita using the panel model. The panel model was set by a balanced panel data for 30 provinces and for the period of 2006~2011. $CO_2$ emission per capita is used as the dependent variable and characteristics of the household and regional physical environmental factors are selected as the explanatory variables. The important findings can be summarized as follows. $CO_2$ emission per capita is influenced by the ratio of the graduate students, household size, the ratio of the old-aged, female economic participation rate. High residential density is negatively affected on $CO_2$ emission. The findings suggest that the effect of policies reducing $CO_2$ emission per capita may vary by characteristics of the household, energy sources and regional climate. The results of this empirical study give some implications to reduce the residential energy consumption in the era of climate change.

• Nuclear Engineering and Technology
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• v.47 no.4
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• pp.424-433
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• 2015

The operating characteristics of hydrogen iodide (HI) decomposition for hydrogen production were investigated using the commercial computational fluid dynamics code, and various factors, such as hydrogen production, heat of reaction, and temperature distribution, were studied to compare device performance with that expected for device development. Hydrogen production increased with an increase of the surface-to-volume (STV) ratio. With an increase of hydrogen production, the reaction heat increased. The internal pressure and velocity of the HI decomposer were estimated through pressure drop and reducing velocity from the preheating zone. The mass of $H_2O$ was independent of the STV ratio, whereas that of HI decreased with increasing STV ratio.

• Bulletin of the Society of Naval Architects of Korea
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• v.22 no.1
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• pp.1-8
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• 1985

The buckling characteristics of cylindrical shells with a circular hole, under axially compressed loads, have been analyzed and the results have been compared with existed experimental results. Deflection function with decay factor is assumed, and stress distribution around a circular hole in tensioned infinite plate is used for formulating buckling energy function. Applying Rayleigh Ritz procedure to this energy function, characteristic equation of eigenvalue problem is determined. Buckling load is defined by the minimum value of eigenvalues calculated according to several decay factors, and as the radius ratios of a circular hole (a/R) and shell thickness ratios (R/t) are varied, the reducing characteristics of buckling load are studied. As a result, buckling loads are reduced by about 50% according to some radius ratios ($a/R{\geq}0.15$) of circular hole and are not nearly affected by shell thickness ratio(R/t).

• The Journal of Industrial Distribution & Business
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• v.8 no.7
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• pp.13-20
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• 2017

Purpose - Performance appraisal has a significant influence on the development of low-carbon tourism distribution. Research design, data, and methodology - Data of this study are collected from 27 provinces (cities) of China. SBM-Malmquist model is used to measure the TFP and its dynamic changes of low-carbon tourism distribution; TOBIT model is used to discuss the factors of TFP of low-carbon tourism distribution. Results - The results show that, there are obvious differences among regional TFP of low-carbon tourism distribution, the average change tends to grow positively in general, and the western region grows fastest on average due to the improvement of technical efficiency and technical progress, while there are technical efficiency improvement but technical regresses in eastern and central regions. The economic scale, economic strength, structure of energy consumption, location quotient and government regulation have a significant positive effect on the TFP of low-carbon tourism; energy intensity, industrial structure and opening degree have a negative effect; investments in fixed assets, intensity of R&D fund and urbanization rate have no significant influence on the TFP of low-carbon tourism. Conclusions - Improving the productivity of low-carbon tourism and reducing regional differences are effective ways to develop low-carbon tourism and enhance tourism competitiveness.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2129-2134
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• 2004

The present study has been conducted to develop a heat pump system using river water of temperature energy which not only belongs to unutilized energy but is a kind of good heat source due to maintain its temperature in a certain degree regardless of seasonal variation. The system did not meet the proposed performance after setup. In this paper, the system performance affected by refrigerant Oil, by pressure drop, or by other factors has been discussed. The followings were obtained : (1) Refrigerant Oil mixture rate was 2.5 in weight percentage, (2) Pressure drop through evaporator was 29.1kPa($3.1^{\circ}C$ in saturated tempearture) (3) Pressure drop from the end of evaporator to compressor inlet was 39.8kPa($4.0^{\circ}C$ in saturated tempearture). (4) The system performance can to be improved by modifying a part of pipe line to compressor, and reducing pressure drop through heat exchangers.