• Environmental and Resource Economics Review
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• v.20 no.2
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• pp.335-356
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• 2011

In this paper, we attempted to suggest a way to evaluate appropriateness and efficiency for the energy consumption structure. For this, based on Markowitz (1952)' mean-variance portfolio model, we constructed an optimal fossil fuel mix. In constructing the optimal mix, we first defined returns on fossil fuels (oil, coal and natural gas) as TOE (Ton of Oil Equivalent) per $1. Then, by using the dynamic latent common factor model, we decomposed the growth rates of the returns on each fossil fuel into two parts : the common part and the idiosyncratic part. Finally, based on the results from the dynamic latent common factor model, we constructed the optimal fossil fuel mix implied by the mean-variance portfolio model. Our results indicate that for the fossil fuel mix to be on the efficient frontier, it is crucial to reduce oil consumption as low as possible. Moreover, our results imply that it is more efficient to increase natural gas consumption rather than coal consumption in reducing oil consumption. These results are in line with the strategies for the future energy consumption structure pursued by Korea and indicate that reduction in oil use can improve overall efficiency in energy consumption.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.103-110
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• 1997

The objective of this study is to provide the information on the small-scale model mix proportion when the behavior of prototype concrete pavement is studied through small-scale model experiments. However it is difficult to obtain a model material to simulate the prototype concrete by scaling the individual components according to the laws of similitude. In this paper, the stress-strain behavior in uniaxial compression is used as a means to correlate materials similitude between the prototype and the model concrete. Based on th results of experiments, We compared the stress-strain curves of prototype and model concrete mixes using a nondimensional basis. In order to simulate the stress-strain curves of prototype concrete, it is important that various mix as of model concrete selected properly which are varied from aggregate grading, cement-aggregate and sand-aggregate ratio.

• Computers and Concrete
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• v.26 no.6
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• pp.505-513
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• 2020

Grading of aggregate influences significantly almost all of the concrete performances. The purpose of this paper is to propose practicable equations that express the optimized total aggregate gradation, by weight or by number of particles in a concrete mix. The principle is based on the fractal feature of the grading of combined aggregate in a solid skeleton of concrete. Therefore, equations are derived based on the so-called fractal dimension of the grain size distribution of aggregates. Obtained model was then applied in such a way a correlation between some properties of the dry concrete mix and the fractal dimension of the aggregate gradation has been built. This demonstrates that the parameter fractal dimension is an efficacious tool to establish a unified model to study the solid phase of concrete in order to design aggregate gradation to meet certain requirements or even to predict some characteristics of the dry concrete mixture.

• Proceedings of the Korean System Dynamics Society
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• 2003.08a
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• pp.49-81
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• 2003

It is one of the important problems how to maintain the optimal electric power generation mix. The Objective of this study is development of a computer model which can be used to forecast the investment of power generation unit by the plant owners after restructuring the electricity industry. The impacts of the various government policies can be analyzed using the computer model, thus the government can formulate effective policies for achieving the desired electric power generation mix.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.4
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• pp.517-527
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• 2021

While the two principles of lean manufacturing and time-driven activity-based costing (TDABC) have been established out of multiple incentives and do not follow the same particular targets, there is substantial commonality between them. In these conditions, the supply management of a multi-product system needs a rigorous production model to minimize costs. In this sense, this paper proposes an interactive model with the consideration of optimizing product-mix decisions using both lean development tools and TDABC. This paper proposes a qualitative approach using the case study of the Iraqi state company for battery production. The suggested model decreased manufacturing time and costs, along with some substantial reduction in idle production capacity by 26 percent in 2019, based on the findings of the case study. On the other hand, the proposed model gives two side advantages: an efficient division of costs on goods due to the use of time spent as a cost factor for products and cost savings due to the introduction of the lean manufacturing approach that reduces all additional costs and increases product-mix decisions. Furthermore, the analytical data gathered here suggests that the incorporation of lean management concepts and TDABC has a strong and important influence on product-mix decisions.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.621-624
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• 2006

This paper presents a novel optimum technique for optimum mix-proportion using database-based prediction model of material properties for an object function or a constraint condition. The proposed technique provides high reliability of results introducing effective region model, which assesses whether the prediction model is effective or not, in optimization process. In order to validate the proposed technique, a genetic algorithm was adopted as a optimum technique, and an artificial neural network was adopted as a prediction model for material properties and as a model for assessing effective region. The mix-proportion obtained from the proposed technique is more reasonable than that obtained from a general optimum technique.

• Journal of Ocean Engineering and Technology
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• v.18 no.1
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• pp.53-62
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• 2004

The Purpose of this study is to recycle the waste concrete, which is generated in huge quantities, from construction works. in order to achieve this goal, it is important to determine the compressive strength, workability, slump, and ultrasonic velocity of recycled aggregate concrete. Thus, several experiment parameters are considered, such as water-cement ratios, sand percentage, and fine aggregate composition ratios, in order to apply the recycled aggregate concrete to pre-cast artificial fishing reefs. From the results, it has been shown that the proper mix designs for reef concrete are W/C=45%, S/a=50%, SR50:SN50 in recycled sand and natural sand mix combination case, W/C=45%, S/a=50%, SC50:SN50 in crushed sand and natural sand mix combination case, W/C=45%, S/a=50%, SR50:SC50 in recycled sand and crushd sand mix combination case. Also, this study shows that the shape and surface roughness of fine aggregate particles have an effect on the strength, slump, ultrasonic velocity of tested concrete, and the compressive strength ratios of 7days' and 90days' curing ages of recycled aggregate concrete are about 70% and 110% of 28days' curing age.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.37 no.6
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• pp.339-349
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• 1988

The simplified simulation technique for the best generation mix is developed and the studied results are described. The best generation mix over study time from the economic point of view can be easily constructed by this technique. Generator maintenance, the operation of pumpgenerator and LNG thermal generator with limited energy are simulated variously, so a role of each generator is also easily evaluated. Through parametric analysis, useful planning guide points are obtained for the best generation mix transition, nuclear power plant construction cost, ruanium cost , oil cost, coal cost and midnight factor in the study case corresponding to real power system size model.

• Korean Journal of Social Welfare
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• v.45
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• pp.220-249
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• 2001

In order to understand the provision of social welfare in Korea, this study puts forward a method to measure and tracks the welfare mix, and applies the method to Korea. This is the goal of this study, which is in three parts. First, I critically review the concept of welfare pluralism and develop the welfare mix model, Second, I present a methodology and technique for measuring and systematically comparing the components of the welfare mix. Third, I examine the roles of five welfare providers including state, market, non-profit organization, enterprise and family in the welfare mix of Korea. This study argues that the welfare mix in Korea has some characteristics of 'residual state, expanded market, negligible voluntary sector, and protective family'. The state in Korea has played a relatively little role in the provision of social welfare, enforcing most Koreans being with a meagre social protection. Thus, most of the 'left' needs for social welfare has to be met in the private sector composed of market and enterprises. In addition, in a situation that self/mutual help through family or community is encouraged, the family has played an important role in the welfare mix. But the role of voluntary sector in the welfare mix has remained negligible. Consequently, the characteristics of the welfare mix in Korea can be best described by a welfare society rather than a welfare state.

• Industry Promotion Research
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• v.7 no.3
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• pp.1-8
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• 2022

Many companies are operating and introducing the research results that corporate counseling contributes to corporate profits and improves the effective welfare of workers. This study was conducted targeting business management experts. As a research question, first, is there a difference in perception among business management experts about business counseling? Second, what is an important marketing 7P mix for revitalizing corporate counseling? Third, there will be differences in the importance of the 7P mix for marketing among business management experts. The results of the quantitative study are as follows. First, business management experts had a positive perception about the intention and necessity of corporate counseling, and marketing was higher than production management by field. The consultation model prefers an external model, and medium-sized enterprises and small and medium-sized enterprises are selected as target companies, and service and manufacturing industries are selected as target industries. The topics are recognized as interpersonal relationships and job stress. Second, price mix, product mix, people mix, and process mix are recognized as important marketing mixes, but companies consider the price mix the most important. Third, there was a difference between corporate management experts in the promotion mix and process, and marketing recognized the promotion mix as important and the process mix was important for financial management. However, there is no difference in the mixes by field except for this, so it can be said that the perception of the marketing mix is similar. Through this study, it is meaningful to present the implications of the marketing mix for awareness and activation of corporate counseling from the corporate point of view.