• Journal of the Korea Society for Simulation
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• v.21 no.3
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• pp.79-88
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• 2012

Recently, the study in efficient operation, maintenance, and equipment-design have been growing rapidly in military industry to meet the required missions. Through out these studies, the importance of Concurrent Spare Parts(CSP) are emphasized. The CSP, which is critical to the operation and maintenance to enhance the availability, is offered together when a equipment is delivered. Despite its significance, th responsibility for determining the range and depth of CSP are done from administrative decision rather than engineering analysis. The purpose of the paper is to optimize the number of CSP per item using simulation and multiple regression. First, the result, as the change of operational availability, was gained from changing the number of change in simulation model. Second, mathematical regression was computed from the input and output data, and the number of CSP was optimized by multiple regression and linear programming; the constraint condition is the cost for optimization. The advantage of this study is to respond with the transition of constraint condition quickly. The cost per item is consistently altered in the development state of equipment. The speed of analysis, that simulation method is continuously performed whenever constraint condition is repeatedly altered, would be down. Therefore, this study is suitable for real development environment. In the future, the study based on the above concept improves the accuracy of optimization by the technical progress of multiple regression.

• Journal of the Korean Magnetics Society
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• v.21 no.2
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• pp.77-82
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• 2011

The use of soft magnetic materials have been increasing in the various industrial fields according to the increasing demand for high performance, automatic, miniaturing equipments in the recent our life. In this study, we investigated the effect of factors on the core loss and magnetic properties of electrical steel and soft magnetic composites. Furthermore, we reviewed the major efforts to reduce the core loss and improve the soft magnetic properties in the two main soft magnetic materials. Domain purification which results from reduced density of defects in cleaner electrical steels is combined with large grains to reduce hysteresis loss. The reduced thickness and the high electrical conductivity reduce the eddy current component of loss. Furthermore, the coating applied to the surface of electrical steel and texture control lead to improve high permeability and low core loss. There is an increasing interest in soft magnetic composite materials because of the demand for miniaturization of cores for power electronic applications. The SMC materials have a broad range of potential applications due to the possibility of true 3-D electromagnetic design and higher frequency operation. Grain size, sintering temperature, and the degree of porosity need to be carefully controlled in order to optimize structure-sensitive properties such as maximum permeability and low coercive force. The insulating coating on the powder particles in SMCs eliminates particle-to-particle eddy current paths hence minimizing eddy current losses, but it reduces the permeability and to a small extent the saturation magnetization. The combination of new chemical composition with optimum powder manufacturing processes will be able to result in improving the magnetic properties in soft magnetic composite materials, too.

• Journal of Service Research and Studies
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• v.9 no.1
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• pp.51-71
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• 2019

The purpose of this research is to analyze the ETF market, which has a large increase in the number of listed shares and the market capitalization, and to identify the investment effects of ETFs. The study procedure and method used to calculate the return and change trend of ETFs for the sample of the transaction information, the transaction amount, and the market capitalization for the period from 2010 to 2018, and performed correlation and regression analysis. As a result, the ETF's total return was 2.11%, the domestic underwriting market ETF yield was 2.39%, and the stock ETF yield was 2.59%, which was lower than the KOSPI 200 index and the KOSPI 200 index. Index ETF was 2.63%, followed by stock ETF and oversea underwriting market ETF. The problem with ETF investment is that the annual return of ETFs and domestic ETFs is as low as 2%, which is not enough for investors to expect more than 5%. The study contributes to the realization of the ETF by analyzing the actual effect of the investment and to establishing considerations when buying ETFs from the viewpoint of investors. The direction of the research is to accumulate more ETF data and present the investment direction precisely.

• International Commerce and Information Review
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• v.16 no.2
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• pp.251-278
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• 2014

This research is about global investment for managing the important position, what Korea is doing in World's main market. Considering there are some differences between developed countries' model and developing countries' model in doing direct overseas investment, they target to get political agreement and develop the new invest plan and strategy by understanding changes of Korean manufacturing companies in direct overseas investment between 2007 and 2012 and analyzing the change of yearly investment motivation factors and acturing factors for investment. The result from this result let us know that company should develop their own idea for their competitive advantage by doing direct overseas investment with the existing the on which convinces the competitive advantage for investing overseas. From the analyzing result, even though it is fairly true that raising wage and getting resources, avoiding customs, and developing alternating industries for export had influenced at the beginning, overseas investing companies' policy will be influenced by the results from studying marketing-pursuit type, which emphasizes to manage trade income and outgo, keeping the balance in the black, ensuring raw materials, local producing and manufacturing by using low-wage people for local sale, and situation for changing investing tendency as service industry.

• International Commerce and Information Review
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• v.15 no.1
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• pp.67-93
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• 2013

This research is about global investment for managing the important position, what Korea is doing in World's main market. Considering there are some differences between developed countries' model and developing countries' model in doing direct overseas investment, they target to get political agreement and develop the new invest plan and strategy by understanding changes of Korean manufacturing companies in direct overseas investment between 2004 and 2011 and analyzing the change of yearly investment motivation factors and acturing factors for investment. The result from this result let us know that company should develop their own idea for their competitive advantage by doing direct overseas investment with the existing the on which convinces the competitive advantage for investing overseas. From the analyzing result, even though it is fairly true that raising wage and getting resources, avoiding customs, and developing alternating industries for export had influenced at the beginning, overseas investing companies' policy will be influenced by the results from studying marketing-pursuit type, which emphasizes to manage trade income and outgo, keeping the balance in the black, ensuring raw materials, local producing and manufacturing by using low-wage people for local sale, and situation for changing investing tendency as service industry.

• Journal of Digital Convergence
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• v.18 no.7
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• pp.157-166
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• 2020

This study examines the status of major corruption in the public and private sectors in Korea. This study adopts the secondary data analysis method, and uses 'The Status of Corruption in Korean Society' released by Ipsos in March 2019. The annual difference analysis is conducted to examine the trend of major corruption, and the results are as follows. First, in the public sector, the number of conspicuous crimes, such as bribery, has decreased, but intelligent crimes that are not easily detected, such as abuse of authority, are increasing. In the private sector, embezzlement was on the decline, but breach of trust remained at a certain level. Second, from 2003 to 2017, the average annual change rate of major corruption in the public sector was 8.0%, while the private sector was 1.8%. Third, the public sector has seen a slight increase in corruption except in 2015, but the private sector has been declining since 2014. This study is different as it makes academic contributions by offering three anti-corruption measures; changing the culture of high power distance, changing the culture of low corruption perception, and abolishing the culture of impunity. Empirical studies using primary data that separate the two groups are required.

• Korean Journal of Environment and Ecology
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• v.26 no.4
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• pp.620-628
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• 2012

This study addressed the influence of forest harvesting on seasonal water table dynamics in small headwater riparian areas. Four treatments including potential Best Management Practices(BMPs) for ephemeral and intermittent streams were implemented(BMP1, BMP2, clearcut and reference). Water table measurements were obtained at bi-monthly intervals for 3 years including one year of pre- and two years of post-harvest observations. Overall, water table responses affected largely by rainfall amount. In addition, significant increases in water table levels following harvesting occurred throughout the two post-harvest years. Water table levels increased up to 28.2cm in the clearcut treatment during 2008 and up to 54.2cm in BMP2 during 2009. However, increase in water table elevation was not directly related to basal area removal despite considerable differences in basal area removed between BMP2 and clearcut treatments. Water table rises were apparent in that water table were more elevated during dry season(June through November) than during wet season(December through May). These seasonal fluctuations were presumably driven by changes in evapotranspiration caused by differences in leaf area of overstory canopy and understory following harvest.

• Korean Journal of Environment and Ecology
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• v.30 no.5
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• pp.848-856
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• 2016

The purpose of this study is to determine the impact on settlement pattern of wintering swans by distribution of rapidly spreading lotus in Junam reservoir. When we investigated the relationship between the spreading lotus and population variation of the wintering swans in all around Nakdong-river estuary, the spreading lotus did not affect the number of swans in Junam reservoir. The occupation ratio of lotus distribution continuously increased from 13.2%(2013) to 19.0%(2014). Before we begin with the investigation, we compared two particular groups: inside of lotus community and far (>100 m) water area from the border of lotus community. At the first survey(2013.12.17), we observed 3.1 times more swan population in the inside, comparing with far water area. The third(2014.01.29.) and fourth(2014.12.03) inquiries also showed respectively 5.5 and 7.5 times higher swan population in the inside and near water area. The second observation was conducted during visitors were increased so these phenomenon was not observed. This result might be explained as the similar environmental condition of habitate for swan and lotus such as less than 1 m water depth. However, we considered that lotus and swan were not relation of conflict due to increasing both lotus community and swan population at the same time. According to the observation that inhabitation density of wintering swans is significantly high in near lotus communities area, at least spread of lotus did not negatively affect the wintering swans.

• Management & Information Systems Review
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• v.35 no.4
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• pp.141-153
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• 2016

This study estimates the productivity change of pharmaceutical industry and decompose the change into technical efficiency change and technological change to explore ways to improve the productive efficiency. Unlike most previous studies, this study employs the non-radial and non-oriented slacks-based Malmquist productivity index which can deals directly with the input excesses and output shortfalls. In addition a smoothed bootstrap method is applied to estimate statistical confidence intervals for the Malmquist Index and its components. For the empirical analysis a balanced panel data set is constructed covering ten years over the period from 2005 to 2014. The input variables used in this study are number of workers, tangible assets and major production cost. The gross production is selected as a main output variable. The empirical results suggest that the productivity of pharmaceutical industry has decreased due mainly to decline in the technological progress rather than improvements in technical efficiency. An analysis result shows that the scale efficiency outweighs the pure efficiency in determining the technical efficiency of pharmaceutical industry. Therefore, in order to enhance the competitiveness of domestic pharmaceutical industry, it is important to continue supporting policies to promote the technology innovation capability through efficient R&D investment and industry reform strategy.

• Journal of Science and Technology Studies
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• v.2 no.2 s.4
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• pp.25-54
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• 2002

Without much communication, large-scale surveys of public knowledge of, and attitudes to, science (quantitative PUS) and case-study analyses of the public's understandings of science in particular (constructivist PUS) have dominated in the public understanding of science (PUS) area. Not only methodological preference but also a strong antipathy against value-orientations that each approach presumed to have and support has been barriers for quantitative PUS and constructivist PUS to benefit each other. In order to overcome such barriers, this paper demonstrates that value orientations guiding quantitative PUS have been much more diverse than what constructivist PUS researchers might think, and that quantitative PUS has indeed yielded the results consistent with and complementary to constructivist PUS. Finally this paper proposes that (1)quantitative PUS should test propositions provided by constructivist PUS, so that it can contribute much to the construction of more generalizable PUS theories and policies, and (2)constructivist PUS uses the outcome of quantitative PUS to develop more complex case studies which consider heterogeneous publics, trends of public evaluations of science, and how public attitudes to science in the abstract and public attitudes to science in particular in a specific context have effect on each other.