• 한국해양공학회지
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• 제22권1호
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• pp.13-21
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• 2008

In this study a method to predict CHF(Critical heat flux) in vertical round tubes with axially non-uniform cosine heat flux distribution for water was examined. For this purpose a local condition hypothesis based CHF prediction correlation for uniform heat flux in vertical round tubes for water was developed from 9,366 CHF data points. The local correlation consisted of 4 local condition variables: the system pressure(P), tube diameter(D), mass flux of water(G), and 'true mass quality' of vapor($X_t$). The CHF data points used were collected from 13 different published sources having the following operation ranges: 1.01 ${\leq}$ P (pressure) ${\leq}$ 206.79 bar, 9.92${\leq}$ G (mass flux) ${\leq}$ 18,619.39 $kg/m^2s$, 0.00102 ${\leq}$ D(diameter) ${\leq}$ 0.04468 m, 0.0254${\leq}$ L (length) ${\leq}$ 4.966 m, 0.11 ${\leq}$ qc (CHF) ${\leq}$ 21.41 $MVW/m^2$, and -0.87 ${\leq}X_c$ (exit qualities) ${\leq}$ 1.58. The result of this work showed that a uniform CHF correlation can be easily extended to predict CHF in axially non-uniform heat flux heater. In addition, the location of the CHF in axially non-uniform tube can also be determined. The local uniform correlation predicted CHF in tubes with axially cosine heat flux profile within the root mean square error of 12.42% and average error of 1.06% for 297 CHF data points collected from 5 different published sources.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권9호
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• pp.3177-3195
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• 2014

In many moving object detection problems of an aerial video, accurate and robust stabilization is of critical importance. In this paper, a novel accurate image alignment algorithm for aerial electronic image stabilization (EIS) is described. The feature points are first selected using optimal derivative filters based Harris detector, which can improve differentiation accuracy and obtain the precise coordinates of feature points. Then we choose the Delaunay Triangulation edges to find the matching pairs between feature points in overlapping images. The most "useful" matching points that belong to the background are used to find the global transformation parameters using the projective invariant. Finally, intentional motion of the camera is accumulated for correction by Sage-Husa adaptive filtering. Experiment results illustrate that the proposed algorithm is applied to the aerial captured video sequences with various dynamic scenes for performance demonstrations.

• 반도체디스플레이기술학회지
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• 제16권3호
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• pp.53-58
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• 2017

Recently, advance in technology have increased the importance of visual inspection in semiconductor inspection areas. In PCB visual inspection, accurate line estimation is critical to the accuracy of the entire process, since it is utilized in preprocessing steps such as calibration and alignment. We propose a line estimation method that is differently weighted for the line candidates using a histogram of gradient information, when the position of the initial approximate corner points is known. Using the obtained line equation of the outline, corner points can be calculated accurately. The proposed method is compared with the existing method in terms of the accuracy of the detected corner points. The proposed method accurately detects corner points even when the existing method fails. For high-resolution frames of 3.5mega-pixels, the proposed method is performed in 89.01ms.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1018-1021
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• 2009

Define a designated eye position (DEP) for the 3D displays is a critical issue. It shows the system performance without content issue. We use luminance meter to capture these optical characteristic and discuss between one point measurement, two points measurement and three points measurement situation.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.201-203
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• 1998

This paper presents the framework for analysis of small-signal stabili1ty. In this framework the equilibrium points of system DAE model are traced using continuation method and instability points are determined on the solution path. Especially Implicit shift QR-modified ARnoldi method is utilized to calculated the rightmost eigenvalues. ISPS measure is utilized to determine critical parameters.

• 한국산학기술학회논문지
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• 제20권8호
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• pp.240-249
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• 2019

본 연구는 간호대학생의 감염관리 인지도, 진로결정자기효능감 및 비판적 사고성향이 감염관리 수행도에 미치는 영향요인을 파악하고자 시도하였다. 대상자는 D시와 K시에 소재한 4개 대학 간호학과 3, 4학년 404명이었다. 자료는 2018년 11월 5일부터 12월 21일까지 자가보고식 설문조사로 수집되었다. 수집된 자료는 SPSS WIN 17.0 프로그램을 이용하여 기술통계, 독립집단 t-test, one-way ANOVA, 사후분석은 Duncan's test, Pearson's correlation coefficients, multiple regression analysis로 분석하였다. 감염관리 인지도는 평균 4.75점, 진로결정자기효능감은 평균 3.02점, 비판적 사고성향은 평균 4.73점, 감염관리 수행도는 평균 4.46점이었다. 간호대학생의 감염관리 수행도에 영향을 미치는 요인은 연령, 감염관리 인지도 및 진로결정자기효능감으로 나타났으며, 설명력은 38.6%였다. 따라서 간호 대학생의 감염관리 수행도를 강화하기 위하여 감염관리 인지도와 진로결정자기효능감을 향상하기 위한 교육프로그램개발이 필요하다.

• 대한수학회지
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• 제53권2호
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• pp.287-304
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• 2016

In this paper, we consider the problem of existence of conformal metrics with prescribed mean curvature on the unit ball of ${\mathbb{R}}^n$, $n{\geq}3$. Under the assumption that the order of flatness at critical points of prescribed mean curvature function H(x) is ${\beta}{\in}[1,n-2]$, we give precise estimates on the losses of the compactness and we prove new existence result through an Euler-Hopf type formula.

• 대한수학회보
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• 제47권6호
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• pp.1235-1250
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• 2010

In this paper we establish the existence of at least three weak solutions for Neumann doubly eigenvalue elliptic systems driven by a ($p_1,\ldots,p_n$)-Laplacian. Our main tool is a recent three critical points theorem of B. Ricceri.

• 한국수정란이식학회지
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• 제8권1호
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• pp.37-44
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• 1993

Nuclear transplantation techinque has been found to be the most potential and efficient method for producing a large number of genetically identical animals from a single embryo. The technical development of nuclear transplantation in mammals and its application to the production of cloned animals were reviewed. For the efficient and successful production of cloned embryos by nuclear transplantation, selection and micromanipulation of recipient eggs or embryos as capacious recipient cytoplasm, and benefitial preparation of multiple totipotent embryonic cells as donor nuclei, and also fusion technique are very critical. Recent works approaching to these critical points were introduced and discussed.

• Journal of applied mathematics & informatics
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• 제38권5_6호
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• pp.407-414
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• 2020

In this article, a second-order Sturm-Liouville problem with impulsive effects and involving the one-dimensional p-Laplacian is considered. The existence of at least three weak solutions via variational methods and critical point theory is obtained.