• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.129-136
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• 1997

The automated ball indentation(ABI) test was utilized to develop a semi-nondestructive method for estimating the fracture toughness( $K_{JC}$ ) in the transition temperature range. The key concept of the method is that the indentation deformation energy to the load at which the mean ball-specimen contact pressure reaches the fracture stress is related to the fracture energy of the material. ABI tests were performed for the reactor pressure vessel(RPV) base and weld metals at the temperatures of-15$0^{\circ}C$~$0^{\circ}C$ and the fracture toughness (estimated $K_{JC}$ ) was calculated from the indentation load-depth data. For all steels the temperature dependence of the estimated fracture toughness was almost the same as that ASTM $K_{JC}$ master curve The reference temperatures( $T_{o}$)of the steels were determined form the estimated $K_{JC}$ versus temperature curves. The reference temperature was well correlated with the index temperature of 41J Charpy impact energy( $T_{41J}$).).).

• Structural Engineering and Mechanics
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• v.70 no.3
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• pp.289-301
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• 2019

Hysteretic energy is defined as energy dissipated through inelastic deformations during a ground motion by the system. It includes frequency content and duration of ground motion as two remarkable parameters, while these characteristics are not seen in displacement spectrum. Since maximum displacement individually cannot be the appropriate criterion for damage assessment, hysteretic energy has been evaluated in this research as a more comprehensive seismic demand parameter. An innovative methodology has been proposed to establish a new equivalent linear model to estimate hysteretic energy spectrum for bilinear SDOF models under two different sets of earthquake excitations. Error minimization has been defined in the space of equivalent linearization concept, which resulted in equivalent damping and equivalent period as representative parameters of the linear model. Nonlinear regression analysis was carried out for predicting these equivalent parameter as a function of ductility. The results also indicate differences between seismic demand characteristics of far-field and near-field ground motions, which are not identified by most of previous equations presented for predicting seismic energy. The main advantage of the proposed model is its independency on parameters related to earthquake and response characteristics, which has led to more efficiency as well as simplicity. The capability of providing a practical energy based seismic performance evaluation is another outstanding feature of the proposed model.

• International Area Studies Review
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• v.20 no.3
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• pp.3-22
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• 2016

This paper uses Dynamic OLS(DOLS) approach to estimate the long-run energy demand functions. The results are compared with those of standard cointegration approach. Cointegration tests verify that there is a cointegration among energy consumption, real GDP, and energy price in China. Johansen approach and DOLS approach are more appropriate to estimate for the long-run energy demand function than Engle-Granger Cointegration approach. DOLS provided significant negative sign of price while Engle-Granger did not. Based on the DOLS results, the elasticities of real GDP and energy price on energy consumption are 0.83 and -0.45 respectively, and their statistical significances are high.

• Journal of the Korea Safety Management & Science
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• v.24 no.3
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• pp.75-84
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• 2022

While protecting its lives and property from natural disasters such as floods and droughts, North Korea needs to develop into an informationized industrial society by securing renewable energy power in the era of energy transition. In addition, existing research has considered that a policy of continuous and consistent expansion of renewable energy based on the safety of the lives of ordinary people could be the solution. South Korea needs to recognize that the supply of energy for a minimum of living is more important to the North Korean people than the economic benefits of securing North Korea's renewable energy market. Therefore, in this paper, from that point of view, we have calculated the amount of electricity that North Korea lacks necessary for the lives of its inhabitants that can be replaced by renewable energy, and considered ways to estimate the market value.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.13 no.4
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• pp.230-236
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• 1984

This paper presents a method for estimating the useful output of solar D.H.W. system. Heating load calculations, climate data and various conditions are used in this procedure to assess the fraction of the monthly solar energy and the actual solar energy supplied by solar energy for particular system. The design procedure presented in this paper referred to the f-Chart Method. The results of analyzing of this study by Fortran programming are as follows ; 1 . The amount of actual solar energy required to the hot water system is slowly rised to the ascend of tilt angle within the range of $45^{\circ}$, with is decreased since $45^{\circ}$. 2. The fraction of solar energy is superior when collector area is $8.64m^2$. 3. At the tilt angle with the range of $37.6^{\circ}\~45^{\circ}$, the amount of actual solar energy established the best results. 4 Both the fraction of solar energy and the actual solar energy are the most suitable during the storage volume is $300{\iota}$.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.61-65
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• 2015

For effective distribution planning and operation, we need a reliable estimation of operation capacity. But it is difficult to ensure reliability due to the low accuracy of section load data, which is used as a basis in estimating the operation capacity. This paper discusses how to improve the accuracy of section load data by analyzing the existing method of estimating the section load, using statistical techniques to adjust the acquired data, and using the section load estimation algorithm to estimate the section load based on the adjusted data.

• Proceedings of the KSRS Conference
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• 2000.04a
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• pp.9-9
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• 2000

For the planning of future land use for economic activities, an essential component is the identification of the vulnerable areas for natural hazard and environmental impacts from the activities. Also, exploration for mineral and energy resources is carried out by a step by step approach. At each step, a selection of the target area for the next exploration strategy is made based on all the data harnessed from the previous steps. The uncertainty of the selected target area containing undiscovered resources is a critical factor for estimating the exploration risk. We have developed not only spatial prediction models based on adapted artificial intelligence techniques to predict target and vulnerable areas but also validation techniques to estimate the uncertainties associated with the predictions. The prediction models will assist the scientists and decision-makers to make two critical decisions: (i) of the selections of the target or vulnerable areas, and (ii) of estimating the risks associated with the selections.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.600-601
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• 2015

Both the importance and process of estimating Nuclear-power plant construction time and cost have increased in significance as energy user costs themselves have become more significant. In estimating construction time, few parameters are more significant than work item production rates and factors significantly affecting the rates. A standardized data collection tool was used to acquire a total of 401 data points from a S Nuclear-power plant project, for selected critical works: form-work, rebar-work, and concrete-pouring. With the data, several hypothesized drivers of the man-hour production rates and crew-day production rates were also analyzed. Findings from this study will enable industry professionals to enhance accuracy of time and cost estimation for nuclear power plant construction.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.162-167
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• 2011

Construction projects are full of risks. This is particularly the case in civil construction projects that are often featured with large scale, complexity and involving a large number of participating parties. The eventuation of risks typically results in extended project durations leading to an increase in the total project budget. The consequence can be amplified considering the significant impacts of civil construction projects on the society, from economical, environmental and social perspectives. This research investigates the significance of risks within civil construction projects and approaches to deal with risks. Semi-structured interviews were undertaken with local industry practitioners in South Australia on this matter. It is found that the industry is fairly aware of risks associated with civil construction projects and subsequently has procedures in place to attempt to minimize the impacts of these risks on the project outcomes. The interview results also indicate that there is limited utilization of software for the risk management purpose from the cost estimation perspective.

• Korean Journal of Community Nutrition
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• v.13 no.1
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• pp.111-124
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• 2008

This study was conducted to develop a computerized food frequency questionnaire (FFQ) for assessing nutritional status of women of child-bearing age. Computerized food frequency questionnaire (FFQ) that reflect intakes of energy, carbohydrate, fat and protein was developed for women of child-bearing age. This FFQ is composed of 61 foods or food groups containing 192 dish items. To estimate of energy intake easily, we have developed a computer program that can be viewed on a computer screen in an actual size of dish items. Nutrient intakes of the last three months by the FFQ was validated with comparing the result of a 3-day diet record through 92 college students aged from 20 to 30. The level of energy, carbohydrate and sodium of estimating by the FFQ method was significantly higher than the level of a 3-day diet records method (p < 0.01). Pearson's correlation coefficients between the two methods were 0.50 for carbohydrate (p < 0.01), 0.55 for energy (p < 0.01) and 0.56 for protein (p < 0.01). Spearman's correlation coefficients were 0.53 for carbohydrate (p < 0.01), 0.55 for energy (p < 0.01) and 0.52 for protein (p < 0.01). The percent of subject in the lowest quartile in a 3-day diet record belonged to the first and second lowest quartile in food frequency questionnaire is 78.2% in energy, 91.3% in carbohydrate, 78.2% in protein, 69.5% in fat. Also, the percent of subject in the highest quartile in a 3-day diet record belong to the first and second highest quartile in food frequency questionnaire is 78.3% in energy, 73.9% in carbohydrate, 82.6% in protein, and 73.9% in fat. On the whole, the result of this study seemed to be in good agreement with other studies. Therefore, the FFQ developed by this study is considered to be a reliable tool to assess nutrients and food intakes for women of child-bearing age.