• Journal of the Korean Solar Energy Society
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• v.27 no.2
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• pp.45-52
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• 2007

Since the atmospheric clearness index is main factor for evaluating global-dimming of atmosphere environment, it is necessary to estimate its characteristics all over the major cities in Korea. We have begun collecting clearness index data since 1982 at 16 different cities and considerable effort has been made for constructing a standard value from measured data at each city. The new clearness data for global-dimming analysis will be extensively used by evaluating atmospheric environment as well as by solar PV application system designer or users. From the results, we can conclude that 1) Yearly mean 61.9% of the atmospheric clearness index was evaluated for clear day all over 2) A significant difference of atmospheric clearness index is observed between 1982-1989 and 1990-1997, 1998-2005 through 16 different cities in Korea.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.458-458
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• 2022

It is essential to reduce global carbon emissions, mainly from energy use. The water supply and distribution sector is a vital part of human society and is one of the primary energy consumers. The procurement and distribution of water require electricity to operate the pump to deliver water to users with sufficient pressure. As the water users are spatially distributed over a wide area, the energy required to deliver water to each user differs depending on the corresponding supplying element (reservoir, tank, pipe, pump, and valve). This difference in energy required for each user also comes with a difference in pressure availability which affects the level of service for individual users and the whole network. Typically, there is a disproportion where users close to the source experience excessively high pressure with low energy consumption. In contrast, remote users need more energy to get the minimum pressure. This study proposes the Energy Return Index (ERI) to quantify the pressure return from particular energy consumption to supply water to each node. The disproportionality can be quantified and identified in the network using the proposed ERI. The index can be applied to optimize the network elements such as pump operation and tank location/size to reach a balanced energy consumption with the appropriate level of service.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1177-1180
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• 2009

• Journal of Nutrition and Health
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• v.34 no.1
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• pp.39-47
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• 2001

The study was conducted to assess the association or physical activity, television watching and energy intake with body fat in 514 adolescents(218 boys, 296 girls) aged 14-17 years. Comparison of the weight status evaluated according to some indicators based on weight and stature was made. The quantitative food frequency was used to determine intakes of total energy and energy from each macronutrient. Television-watching time was used as an index of inactivity and time spent performing extra-curricular physical exercise or playing was used a index of activity, BMI(body mass index) was used as index of body fat. Weight status varied by the indicators used. Using BMI, Broca and Rohrer index, 54-59% of boys and 38-57% of girls were underweight decreased(23% of boys and 26% of girls) and the of overweight increased (9.3% of boys and 7.8% girls), when adolescents whose BMI are<=15th percentiles for age and sex, and >= 85th percentiles of standard growth charts of Korean Children and aldosescents(1998) were classified as underweight and overweight, respectively, Girls tended to get fatter compared to boys who showed greater skeletal development. There were no significant correlations between BMI and total energy intake, energy intakes from macronutrient and physical activity level. These lack of association seems to be related to indication that BMI reflects total body mass rather than fatness. Mpreover, the effect of growth may interact with diet intake or physical activity level. Although BMI was not related to physical activity, television-watching time was negatively correlated with physical activity. Television-watching time was positiviely correlated with energy intake in girls. In adolescents, criteria for weigh status based on weight and stature must be age- and sex-specific in that weight status varied by indicators whether gender and higher were taken into consideration or not. If follows that each hourly increment of television watching may be related to fatness of adolescents, because hours certainly reduce the opportunity to be active and increase th energy intake.(Korean J Nutrition 34(1):39-47, 2001)

• Journal of Korean Medicine Rehabilitation
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• v.19 no.1
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• pp.125-134
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• 2009

Objectives : The purpose of this study is to find out the effects of muscle energy techniques on nuchal pain caused by traffic accidents. Methods : The 20 patients were divided into 2 groups: group A was treated except muscle energy techniques and group B was treated with muscle energy techniques. Both groups were treated with acupunture treatment, physical theraphy and herbal medication. Patients were evaluated by McGill Pain Questionnaire-Short Form(SF-MPQ), Pain Disability Index(PDI) and Neck Disability Index(NDI) in traffic accident patients. Results : 1. Both Group were significantly decreased in sensory of SF-MPQ, VAS, PDI and NDI after 7 days of treatment. 2. Group B compared with the Group A was significantly decresed in VAS, PDI after 7 days of treatment. Conclusions : We found out that muscle energy techniques is considered to be effective and useful on nuchal pain caused by traffic accidents.

• Journal of Energy Engineering
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• v.23 no.2
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• pp.93-101
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• 2014

How to determine the extent of national energy security? In this paper, we estimate it by comparative analysis of South Korea and other OECD countries in terms of energy diversity (fuel diversity). Energy security consists of 4 key factors such as availability, accessibility, acceptability, affordability. Especially the importance of accessibility can grow as local imbalance of supply and demand increases. As a proxy of the accessibility, fuel diversity can be a significant indicator to estimate a measure of energy security. In this paper, we use Shannon-Wiener index to measure energy diversity. If fuel diversity increases, the stability of energy security also should increase, because of the smoothing effect to lessen dependence on key energy sources. In 2012 Korean growth rate of H-index (energy diversity) is 18.38%, which is higher than other OECD countries. However, Korean H-index itself is 1.93, lesser than other countries. Shift from oil to coals/gas within fossil fuels has more impact on H-index than weight transition from fossil fuels to renewable energies in Korea. We conclude that more renewable energy is an effective solution to achieve higher energy diversity and ultimately higher energy security as the same as the German case.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.4
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• pp.27-37
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• 1995

A performance index is very important and indispensable to the evaluation of automatic steering system of ships in open sea from the viewpoint of energy saving. In this paper, we derive the performance index of automatic steering system from the concept of energy loss of propulsive power. The index is found to consist of three terms, energy loss due to elongation of sailing distance, energy loss due to steering, and energy loss due to yawing motion. We also provide two kinds of calculation method on the performance index ; frequency response analysis and digital simulation. The numerical calculations are carried out for an ore carrier and a fishing boat by both methods. The frequency response analysis is found to be useful if the system is linear and the disturbance on ship is not large. If the system is nonlinear or the disturbance is excessive, the method of digital simulation has to be applied for the accurate evaluation of the performance index. Further investigations into the effects of nonlinear elements such as weather adjuster, power unit etc. on the performance index, will be dealt with in another paper.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1354-1359
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• 2014

A survey is carried out for the future energy sources to be used for ship's propulsion and ship's machinery and operations. 44 global experts from Korea, America, Norway, Denmark, Japan and German who are currently working in the shipyard and offshore fields participated at the survey. Quantitative predications on the market shares of various energy sources, such as oil, LNG, fuel cell, wind energy, solar energy and nuclear energy are made. MPI (market prediction index) is considered as a quantitative index for easy comparison between future's energy sources used for ship's propulsion and operations. It is expected that the MPI of LNG becomes twofold in 2020 against 'before 2016'. It could be also said that hydrogen based fuel cell is expected to increase rapidly for the coming years unless a new alternative energy appears.

• ETRI Journal
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• v.45 no.4
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• pp.636-649
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• 2023

Renewable energy generation cannot be consistently predicted or controlled. Therefore, it is currently not widely used in the electricity market, which requires dependable production. In this study, reliability- and variance-based controls of energy storage strategies are proposed to utilize renewable energy as a steady contributor to the electricity market. For reliability-based control, photovoltaic (PV) generation is assumed to be registered in the power generation plan. PV generation yields a reliable output using energy storage units to compensate for PV prediction errors. We also propose a runtime state-ofcharge management method for sustainable operations. With variance-based controls, changes in rapid power generation are limited through ramp rate control. This study introduces new reliability and variance indices as indicators for evaluating these strategies. The reliability index quantifies the degree to which the actual generation realizes the plan, and the variance index quantifies the degree of power change. The two strategies are verified based on simulations and experiments. The reliability index improved by 3.1 times on average over 21 days at a real power plant.

• Steel and Composite Structures
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• v.10 no.4
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• pp.331-348
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• 2010

Ample research effort has been oriented into developing damage indices with the aim of estimating in a reasonable manner the consequences, in terms of structural damage and deterioration, of severe plastic cycling. Although several studies have been devoted to calibrate damage indices for steel and reinforced concrete members; currently, there is a challenge to study and calibrate the use of such indices for the practical evaluation of complex structures. The aim of this paper is to introduce an energy-based damage index for multi-degree-of-freedom steel buildings that accounts explicitly for the effects of cumulative plastic deformation demands. The model has been developed by complementing the results obtained from experimental testing of steel members with those derived from analytical studies regarding the distribution of plastic demands on several steel frames designed according to the Mexico City Building Code. It is concluded that the approach discussed herein is a promising tool for practical structural evaluation of framed structures subjected to large energy demands.