• Journal of Korea Trade
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• 제25권4호
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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.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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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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• 제20권1호
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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.

• 대한소아치과학회지
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• 제43권2호
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• pp.151-157
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• 2016

본 연구는 3-6세 어린이의 비만과 치아우식 사이의 관련성을 알아보고자 하였다. 익산시 소재의 어린이집과 유치원 아동 769명을 대상으로 우식경험유치지수(dft index)를 조사하고, 신장과 체중을 측정하여 체질량지수(body mass index)를 계산하였다. 표준성장도표의 체질량지수 백분위수를 이용하여 저체중, 정상, 비만위험, 비만의 4개 군으로 분류하였고, 저체중인 15명을 제외한 754명을 대상으로 분석하였다. 평균 dft index는 3.39였고, 남녀간의 유의한 차이는 없었다. 연령에 따라 dft index는 증가하였으며, 4세에서 5세에서 증가폭이 가장 컸다. 비만위험군과 비만군은 정상군보다 더 많은 우식경험률을 보였다. 그러나 3세 집단을 제외한 모든 연령군에서 정상, 비만위험, 비만 집단간의 통계적으로 유의한 차이를 보이지 않았다. 결론적으로 비만과 유치열의 우식경험에는 유의한 관련성이 없음을 알 수 있었다.

• 수산해양기술연구
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• 제48권3호
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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).

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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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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• 제33권3_4호
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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.

• 한국건설관리학회논문집
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• 제13권1호
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• pp.87-94
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• 2012

공동주택 재건축사업은 주거환경개선 및 신규 주택공급이라는 도시 계획적 순기능을 가지고 있지만, 원주민의 재정착 실패 및 소득 재분배 실패, 부동산투기, 주택가격의 급상승, 사업주체간의 갈등, 제도 미비 등 복합적인 요인에 의하여 사업 의도가 왜곡되고 재건축사업의 추진이 원활히 진행되지 못하고 있는 실정이다. 재건축사업 주체간의 갈등은 사소한 갈등이 확산되어 분쟁과 소송으로 이어지며, 그 결과 재건축사업이 원활히 추진되지 못하게 되어 사업기간과 비용을 증가시키거나 중단되는 경우가 발생하게 된다. 본 논문은 재건축사업의 역기능 중 사업주체간의 갈등을 예방하고 해결하기 위한 노력으로 재건축사업 추진과정을 중심으로 갈등지수를 산정하고 갈등지수를 이용하여 재건축사업의 기간과 비용을 예측하고자 한다. 갈등지수는 재건축사업의 주체간의 갈등요인을 중심으로 신정하며, 갈등지수를 포함한 여러 가지 독립변수를 이용하여 재건축사업의 기간과 비용을 예측한다. 또한 갈등지수의 산정과 사업기간 및 비용 예측을 통하여 사업주체간의 분쟁과 경제적 손실을 최소화 하고 성공적인 재건축사업의 추진에 기여할 수 있다.

• 보건행정학회지
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• 제7권1호
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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.

• 한국광학회지
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• 제31권6호
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• pp.321-327
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• 2020

기판 위에 코팅된 박막의 빛 반사 특성에 대해 연구하였다. 입사 매질로 굴절률이 큰 프리즘을 사용하여 박막/기판 계의 내부 전반사 현상과 공기/박막/기판 계가 이루는 도파로로 빛이 결합되어 들어가는 현상을 종합적으로 비교, 연구하였다. 박막의 굴절률이 기판의 굴절률보다 큰 경우에는 빛의 입사각을 증가시켜 나가면 먼저 기판에 의한 전반사가 일어나고, 그 이후 도파로 모드를 맞추는 좁은 각 영역에서 반사율이 떨어지는 현상을 볼 수 있으며, 이것을 이용하여 박막의 굴절률과 두께를 정확히 측정할 수 있다. 반면에 박막의 굴절률이 기판의 굴절률보다 작은 경우에는 도파로 모드가 존재하지 않는다. 이 경우 덩어리 매질에서처럼 뚜렷하지는 않지만 박막에 의한 전반사가 간섭무늬를 동반하여 나타난다. 본 연구에서는 프리즘/박막/기판 구조에서 일어나는 반사 현상을 전반적으로 관측하고 분석하여, 두 경우 모두 박막의 굴절률을 측정할 수 있는 가능성을 조사하였다.