• Journal of Korea Trade
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• v.25 no.4
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• pp.1-16
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• 2021

Purpose - This study reviews changes in the steel export-import structure between Korea and Japan to strengthen the competitive advantage of the Korea Steel industry using a trade-related index. Design/methodology - This study focuses on analyzing comparative advantage based on the trade intensity index (TII), revealed comparative advantage index (RCA), and trade specialization index (TSI). Findings - Korea's steel import from Japan increased due to the domestic supply shortage of HR (Hot Rolled Coil) and Plate, rather than the sharp decline of the domestic steel industry's competitiveness in 2010. However, after the completion of Hyundai Steel's blast furnace, the Korea Steel industry solved the supply shortage. Additionally, the import of Japanese steel products had decreased significantly from 2009 to 2019. Originality/value - This study attempts to analyze Japanese steel products' competitiveness in trade and the domestic influence of high-quality Japanese steel products. These results are connected to domestic steel supply and demand structure and relations with the Japanese steel industry. After completing Hyundai Steel's blast furnace, the Korea Steel industry solved the supply shortage, and the import of Japanese steel products has decreased significantly from 2009 to 2019.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.353-354
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• 2002

This study represents the newly advanced formulation of hydraulic fluids for extended drain interval and introduces the performance results of used oil samples from various excavators. The used oil samples, in this paper, show that there is a sharp change in viscosity drop and moderate additive depletion. For the extension of hydraulic fluid life. it is necessary to improve the stability of viscosity and oxidation. New target properties from the used oil analysis were proposed for extended life. Hydraulic oil with the viscosity index of 140 and improved thermal stability consists of group III base oil, showed the possibility of extension of fluid life.

• Tribology and Lubricants
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• v.20 no.1
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• pp.33-40
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• 2004

This study represents the newly advanced formulation of hydraulic fluids for extended drain interval and introduces the performance results of used oil samples from various excavators. The used oil samples, in this paper, show that there is a sharp change in viscosity drop and moderate additive depletion when viscosity index of hydraulic oil is very high. For the extension of hydraulic fluid life, it is necessary to improve the stability of viscosity and oxidation. New target properties from the used oil analysis were proposed for extended life. Performance of newly developed hydraulic oil based on used oil analysis is compared with previously used one. The properties of new formulation are the viscosity index of 140 and improved thermal stability consists of VHVI base oil. Field test results showed the possibility of extension of fluid life. Additionally, for development of high performance product, new required propertied and performances were discussed.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.2
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• pp.151-157
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• 2016

The purpose of this study was to evaluate the relationship between obesity and dental caries in young children. The subjects were 769 children aged 3 to 6 years, in Iksan, Korea. Body mass index (BMI) and decayed and filled primary teeth (dft) were recorded. Children were classified into four groups (underweight, normal, obese at risk, and obese) according to their BMI percentile. The data of 754 participants, excluding 15 underweight children, were analyzed. The mean dft index was 3.39. There were no significant differences in the number of caries according to gender. The dft index increased significantly with age, with a sharp increase between ages 4 and 5. Children in the obese at risk and obese groups had more caries than those in the normal group. However, there were no statistically significant differences in dft index values between BMI-categorized groups except in 3-year-olds. These findings suggest that there is no significant connection between obesity and dental caries in primary teeth.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.3
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• pp.217-226
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• 2012

Reproductive ecology of the sharp toothed eel, Muraenesox cinereus was investigated based on the samples captured in southern Korean waters from January 2010 to December 2011. Gonadosomatic index began to increase in April, and reached maximum between July to August. After spawning it began to decrease from October. Reproductive season was estimated to April-September, with peak in July. Fecundity was proportional to the size of the female, with the clutch size varying from 56,000 eggs in the smallest female (anal length, 27.0cm) to 1,400,000 eggs in the largest (anal length, 49.5cm). Size at 50% sexual maturity ($AL_{50}$), determined from mature females, were 21.9cm. Annual reproductive cycles of this species could be divided into four successive stages; immature stage (October-February), maturing stage (March-May), mature stage (June-August) and spent stage (August-October).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.634-637
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• 2005

A subjective index of sound quality when it hit him is required since human listening is very sensitive and complex. Sound quality evaluation it leads consequently rightly in each situation and it composes a sound quality factor. But one of the levels in interest frequency range is substitute we cannot see the tendency of frequency substitute at whole that is executes a clear voice evaluation. Design of experiment is used and dividing 12 equally in frequency domain, the sound quality using sharpness and annoyance is performed by modifying each of frequency domains. Design of experiment method reduces much number experiment very effectively and each main effect of domain solution analysis, such as a case of sharpness and annoyance, the change of domain (increase and decrease of sound pressure level, or change nil) can grasp a type of effect should have influenced to a sound quality, and it will be able to select the objective frequency domain which hits to the sound quality. Through these obtained results the physical changes of level at arbitrary frequency domain sensitivity can be adapted.

• Journal of applied mathematics & informatics
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• v.33 no.3_4
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• pp.365-377
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• 2015

For a (molecular) graph, the first and second Zagreb indices (M₁ and M₂) are two well-known topological indices, first introduced in 1972 by Gutman and Trinajstić. The first Zagreb index M₁ is equal to the sum of the squares of the degrees of the vertices, and the second Zagreb index M₂ is equal to the sum of the products of the degrees of pairs of adjacent vertices. Let $K_{n_1,n_2}^{P}$ with n₁ $\leq$ n₂, n₁ + n₂ = n and p < n₁ be the set of bipartite graphs obtained by deleting p edges from complete bipartite graph K_n1,n2. In this paper, we determine sharp upper and lower bounds on Zagreb indices of graphs from $K_{n_1,n_2}^{P}$ and characterize the corresponding extremal graphs at which the upper and lower bounds on Zagreb indices are attained. As a corollary, we determine the extremal graph from $K_{n_1,n_2}^{P}$ with respect to Zagreb coindices. Moreover a problem has been proposed on the first and second Zagreb indices.

• Korean Journal of Construction Engineering and Management
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• v.13 no.1
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• pp.87-94
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• 2012

The apartment reconstruction projects have the proper functions such as residential environment improvement and the new housing allocation system; however, intention of the projects are distorted by the combination of factors, like failure of relocation of the original occupants and income redistribution, speculation in real estate, sharp rise in housing price, disputation between various interested parties, inadequate system and etc and it makes the projects unable to go well. Disputations and litigations are due to spread of the small conflict. As a result of the problems, it could not going smoothly and that lead to increase or stop the period and cost. This study is to estimate the period and cost using the conflict index so as to prevent and solve the problem which is among the conflict in the reverse functions. The conflict index has estimated focus on the conflict impact and the period and cost has been estimated using an variable independent including the conflict index. Also, estimated the conflict index and estimate of the period and cost are able to succeed with a minimum of disputation and money.

• Health Policy and Management
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• v.7 no.1
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• pp.155-182
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• 1997

Objectives : This study was designed to compare North Korea and South Korea in measures of the quality of life (physical quality of life index and human development index) and to investigate the impact of selected medical and socioeconomic factors on PQL variables. Data and Methods : The World Bank, the United Nations Development Programme, and Population Reference Bureau were the principal sources of statistical data of 121 countries. Variables included infant mortality, life expectancy at birth, literacy rate, secondary school enrollment (male and female), GNP per capita, population per doctor, daily calorie supply per capita, and a composite PQL index. The Ordinary Least Square model was employed for cross-countries analysis. Findings : Both countries under quite different political and economic systems saw big improvememts in the quality of life, reducing mortality and prolonging life expectancy during the past three decades. In recent decad, however, North Korea has experienced abrupt exacerbation in the quality of life. Significant improvements in infant mortality of the population wer attributable mainly to GNP per capita and the secondary school enrollemt of female. The principal predictors of life expectancy at birth were population per doctor, infant mortality, and literacy rate. The secondary school enrollment of female and population per doctor were significantly associated with improvements in the physical quality of life index (PQLI). Conclusion : The results of this study confirmed a point illustrated by other studies : The association between quality of life as a measure of health status and socioeconomic factors was strong and positive. The important contribution of educational attainment in general, female education level in particular to improvements in the quality of life deserves good news for building an integrated health care system in the reunified Korea, taking into account the high level of education two koreas are enjoying. Meanwhile, when a sharp drop in the quality of life has been observed in North Korea under serious economic difficulties and food shortage in recent decade, the significant contribution of economic development to improvements in the quality of life poses bad nows for reunifying Korean health care in economic terms.

• Korean Journal of Optics and Photonics
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• v.31 no.6
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• pp.321-327
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• 2020

We investigated the light reflection from thin films coated on substrates. Using a prism with a high refractive index as the incident medium, the phenomena of the total internal reflection (TIR) of the prism/film/substrate system and the light coupling into the optical waveguide formed by the air/film/substrate system were comprehensively studied and compared. If the refractive index of the thin film is greater than that of the substrate, within the TIR region of the substrate, sharp reflection minima occur at specific angles where the waveguide modes are excited, that can be used to accurately measure the refractive index and thickness of a thin film. On the other hand, if the refractive index of the thin film is smaller than that of the substrate, such waveguide modes do not exist. In this case, although not so distinct as a bulk medium, the TIR effect of the thin film is still observable, accompanied by an interference pattern. In this study we analyzed the overall reflection phenomena occurring from prism/film/substrate structures, to investigate the possibility of measuring the refractive index of a thin film in both cases.