• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2B
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• pp.179-189
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• 2010

This paper presents a numerical investigation of vorticity generation in fully vegetated open-channel flows. The Reynolds stress model is used for the turbulence closure. Open-channel flows with rough bed-smooth sidewalls and smooth bed-rough sidewalls are simulated. The computed vectors show that in channel flows with rough bed and rough sidewalls, the free-surface secondary currents become relatively smaller and larger, respectively, compared with that of plain channel flows. Also, open-channel flows over vegetation are simulated. The computed bottom vortex occupies the entire water depth, while the free-surface vortex is reduced. The contours of turbulent anisotropy and Reynolds stress are presented with different density of vegetation. The budget analysis of vorticity equation is carried out to investigate the generation mechanism of secondary currents. The results of the budget analysis show that in plain open-channel flow, the production by anisotropy is important in the vicinity of the wall and free-surface boundaries, and the production by Reynolds stress is important in the region away from the boundaries. However, this rule is not effective in vegetated channel flows. Also, in plain channel flows, the vorticity is generated mainly in the vicinity of the free-surface and the bottom, while in vegetated channel flows, the regions of the bottom and vegetation height are important to generate the vorticity.

• Journal of the Korean Vacuum Society
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• v.4 no.1
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• pp.109-117
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• 1995

고에너지 이온주입시 격자결함의 생성 및 열처리 거동이 double crystal X-ray와 단면 TEM을 사용하여 연구되었다. 3MeV P+ 이온주입한 실리콘의 DCXRD 분석 결과조사량 증가에 따라 모재 내의 변형량은 증가하였다. HRTEM 분석 결과 고에너지 이온주입시 결함은 표면 부근에 희박하고 Rp 부근에 집중되어 있었다. 또한 이온주입 상태의 결함층은 dark band의 형태로 존재하였으며 열처리시 이차결함은 이곳으로부터 생성됨이 관찰되었다. 3MeV P+,$1X1015extrm{cm}^2$의 조건으로 이온주입된 실리콘 시편의 열처리에 따른 X-ray rocking curve 분석을 통하여 열처리 온도가 $550^{\circ}C$에서 $700^{\circ}C$로 증가함에 따라 모재 내부의 최대 변형량이 7X10-4에서 2.9X10-4으로 감소함이 관찰되었다. 특히 $550^{\circ}C$ 열처리한 시편의 경우 표면으로부터$-1.5mu$m 영역에 작은 변형층이 넓게 잔존하였으며 열처리온도를 $700^{\circ}C$로 증가한 경우 제거되었다. 이온주입시 생성된 일차결함들은 $700^{\circ}C$ 열처리시 $60^{\circ}$ 전위와 <112> 막대 모양 결함, $1000^{\circ}C$ 열처리시 <110>방향의 전위루프로 열처리 조건에 따라 여러 가지 모양의 이차결함으로 변화하였다. 고에너지 이온주입에 의해 발생한 이차결함은 고온에서도 안정하여 고온 열처리에 의한 제거가 용이하지 않았다.

• Journal of the Korean Electrochemical Society
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• v.11 no.3
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• pp.211-222
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• 2008

Li secondary batteries, which have been in successful commercialization, are becoming important technology as power sources in non-IT application like HEV(Hybrid Electric Vehicle) as well as in portable electronics. It is not the overstatement that the commercialization of Li secondary battery was a result of the development of carbonaceous anode material and safety mechanisms. The R&D of electrode materials of Li secondary batteries is one of the core technologies in the development and it has enormous influences on various fields as well as on the battery industry. Here, the current research of anode materials is described and the underlying problems associated with development, advantages and drawbacks is analyzed.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.178-178
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• 2015

본 연구는 복단면구조의 수로에서 이차류 및 흐름특성을 비교, 관측하는 것이며 이러한 흐름특성을 연구하기 위해 폭 1.2 m, 길이 14 m, 높이 0.6 m인 실험수로를 이용하여 수심비 0.25 및 0.40 조건에서 0.05, 0.10 CMS의 유량으로 총 4가지 조건으로 실험을 진행하였고 이를 비교하기 위해 3차원 수치해석모형인 FLOW-3D를 이용하여 수치해석결과와 수리실험결과를 비교하였다. 주수로 및 홍수터의 수심과 유량의 조건이 각각 다른 4가지 조건 별 변화를 수리실험과 수치해석을 통해 분석한 결과, Shino & Knight(1991)에서의 언급한 내용과 부분적으로는 동일한 결과를 보였으나, 수치해석 부분에서의 결과와는 차이를 보였다. 일반적으로 복단면구조에서 발생하는 이차류는 수위 및 수심별 유속의 차이에서 발생하는 연직방향의 유속의 영향과 복단면과 주수로의 구조적 차이에서 발생하는 횡방향 유속의 영향과 같은 복합적인 작용으로인해 발생하게 되지만 수치해석의 결과에서는 수위차이에 의한 연직방향의 유속이 횡방향 유속보다 지배적인 결과를 보여 본 연구 중 고유속의 조건에서는 이차류의 형성이 수리실험 및 기존 연구결과들과 차이를 보였다.

• The Korean Journal of Applied Statistics
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• v.7 no.1
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• pp.69-74
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• 1994

Kim (1992) derived influence functions of rows and columns on the eigenvalues obtained in correspondence analysis (CA) of two-way contingency tables. As in principal component analysis, the eigenvalues are of great importance in CA. The goodness of a two dimensional correspondence plot is determined by the ratio of the sum of the two largest eigenvalues to the sum of all the eigenvalues. By investigating those rows and columns with high influence, a correspondence plot may be improved. In this paper, we extend the influence functions of CA to multiple correspondence analysis (MCA), which is a CA of multi-way contigency tables. An explicit formula of the influence function is given.

• Proceedings of the Korean Statistical Society Conference
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• 2005.05a
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• pp.291-298
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• 2005

지속성 외래 복막투석은 말기 신부전 환자들에게 널리 시행하는 신 대체 요법으로, 복막투석 환자에게서 주된 합병증으로 일어나는 단백질-열량 영양실조를 치료하기 위하여 아미노산을 복강 내로 주입하는 치료방법이다. 이현석 등(2004)의 연구에서는 아미노산 복막 투석액(IPAA)이 영양실조 환자들에게 실제로 영양상태에 미치는 영향을 평가하기 위하여 지속성 외래 복막투석 환자 43명을 12개월 동안 3개월 주기로 관측하여 얻어낸 반복측정자료를 바탕으로 IPAA의 효과 여부에 따라 반응군과 비반응군을 분류하였다. 본 논문에서는 이러한 두 그룹을 효과적으로 분류할 수 있는 분류기준변수들을 찾아내고 이 분류기준변수의 값을 바탕으로 새로운 환자에게 IPAA의 투여 여부를 진단할 수 있는 여러 분류방법들을 고찰하여 비교 연구하였다. 모수적인 방법으로 선형판별분석, 이차판별분석 및 로지스틱 판별분석을 소개하고 비모수적인 방법으로 support vector machine(SVM)을 소개하여 분류분석의 결과를 비교하여 두 그룹을 최소한의 오류로 분류하는 방법을 제안하였다.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.115-121
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• 2020

The primary aim of this paper is to discuss the historical development or grammaticalization of English adverbial -ly suffix and provide a diachronic analysis of manner adverbs and sentence adverbs from the perspective of secondary grammaticalization. The grammaticalization includes both the primary grammaticalization from a lexical to a grammatical and the secondary grammaticalization from a less grammatical to a more grammatical status. The emergence of the manner adverbs is due to the primary grammaticalization from OE adjectival suffix -lic to ME adverbial suffix -ly. In contrast, the emergence of sentence adverbs is due to the secondary grammaticalization from manner adverbs in VP domain to sentence adverbs in TP domain with grammatical features of tense and modality. This paper concludes that the secondary grammaticalization of the English adverbial -ly suffix includes the change from manner adverbs to sentence adverbs which obtain a new grammatical function of tense and modality.

• Communications of Mathematical Education
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• v.24 no.3
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• pp.731-744
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• 2010

Nowadays in school mathematics, the skill and method for solving problems are often emphasized in preference to the theoretical principles of mathematics. Students pay attention to how to make an equation mechanically before even understanding the meaning of the given problem. Furthermore they do not get to really know about the principle or theorem that were used to solve the problem, or the meaning of the answer that they have obtained. In contemporary textbooks the conic section such as circle, ellipse, parabola and hyperbola are introduced as the cross section of a cone. But they do not mention how conic section are connected with the quadratic equation or how these curves are related mutually. Students learn the quadratic equations of the conic sections introduced geometrically and are used to manipulating it algebraically through finding a focal point, vertex, and directrix of the cross section of a cone. But they are not familiar with relating these equations with the cross section of a cone. In this paper, we try to understand the quadratic curves better through the analysis of the discussion made in the process of the discovery and eventual development of the conic section and then seek for way to improve the teaching and learning methods of quadratic curves.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.1
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• pp.68-72
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• 2007

Flounder is one of the major aquacultured fish and of an economically important item in Korean fisheries. Recently, there are trends of research worldwide that aim to analyze and characterize a whole genome or a whole proteome of interesting species. The data are utilized for the understanding and development of preventive and curative technologies for the serious diseases. However, there are very limited information of proteome for marine organisms, we optimized first the conditions for two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) with serum form a marine fish, flounder (Paralichthys olivaceus). A pre-treatment of serum and an optimization of protein concentration analyzed were surveyed for enhancing the separation for proteins. A statistical analysis was performed on the overall 1,820 protein spots to overcome the variability among individual fishes.

• Polymer Science and Technology
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• v.11 no.6
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• pp.798-805
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• 2000