• Journal of applied mathematics & informatics
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• 제28권1_2호
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• pp.515-521
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• 2010

In multivariate analysis, the inversion formula of the Stieltjes transform is used to find the density of a spectral distribution of random matrices of sample covariance type. Let $B_n\;=\;\frac{1}{N}Y_nY_n^TT_n$ where $Y_n\;=\;[Y_{ij}]_{n\;{\times}\;N}$ is with independent, identically distributed entries and $T_n$ is an $n\;{\times}\;n$ symmetric non-negative definite random matrix independent of the $Y_{ij}$'s. In the present paper, using the inversion formula of the Stieltjes transform, we will find that the limiting distribution of $B_n$ has a continuous density function away from zero.

• Advances in environmental research
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• 제4권4호
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• pp.263-271
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• 2015

In this study, the effect of initial nitrate loading on nitrate removal and byproduct selectivity was evaluated in a continuous system. Nitrate removal decreased from 100% to 25% with the increase in nitrate loading from 10 to $300mg/L\;NO_3-N$. Ammonium selectivity decreased and nitrite selectivity increased, while nitrogen selectivity showed a peak shape in the same range of nitrate loading. The nitrate removal was enhanced at low catalyst to nitrate ratios and 100% nitrate removal was achieved at catalyst to nitrate ratio of ${\geq}33mg\;catalyst/mg\;NO_3-N$. Maximum nitrogen selectivity (47%) was observed at $66mg\;catalyst/mg\;NO_3-N$, showing that continuous Cu-Pd-NZVI system has a maximum removal capacity of 37 mg $NO_3{^-}-N/g_{catalyst}/h$. The results from this study emphasize that nitrate reduction in a bimetallic catalytic system could be sensitive to changes in optimized regimes.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제17권2호
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• pp.133-152
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• 2013

In this research, we investigated students' understanding of the definitions of sequence of continuous functions and its uniform convergence. We selected three female and three male students out of the senior class of a university and conducted questionnaire surveys 4 times. We examined students' concept images of sequence of continuous functions and its uniform convergence and also how they approach to the right concept definitions for those through several progressive questions. Furthermore, we presented some suggestions for effective teaching-learning for the sequences of continuous functions.

• 대한산업공학회지
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• 제23권4호
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• pp.661-667
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• 1997

We consider a generalized problem of the continuous multiple choice knapsack problem and study on the LP relaxation of the candidate problems which are generated in the branch and bound algorithm for solving the generalized problem. The LP relaxed candidate problem is called the generalized continuous multiple choice linear knapsack problem and characterized by some variables which are partitioned into continuous multiple choice constraints and the others which only belong to simple upper bound constraints. An efficient algorithm of order O($n^2logn$) is developed by exploiting some structural properties and applying binary search to ordered solution sets, where n is the total number of variables. A numerical example is presented.

• 한국기후변화학회지
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• 제6권3호
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• pp.175-184
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• 2015

In this study GC and PAS were used to calculate $N_2O$ concentration of exhaust gas from Wood Chip combustion system. Fuel supplied to the incinerator was collected and analyzed and then the analysis result was used to calculate $N_2O$ emissions. Tier 3 and Tier 4 Method were used to calculate the $N_2O$ emissions. Plant's Specific emission factor of $N_2O$ by Tier 3 Method was 0.35 kg/TJ, while default emission factor of Wood?Wood Waste proposed by 2006 IPCC G/L was 4 kg/TJ. So the $N_2O$ emission factor of this study was 3.65 kg/TJ lower compared to the IPCC G/L. The total emissions calculated by Plant's specific emission factor was 4.22 kg during the measuring period, but by Tier 4 Method it was 7.88 kg. This difference in emissions was caused by the difference of continuous measuring and intermittent sampling. It would be necessary to apply continuous measuring to calculate emissions of $Non-CO_2$ gas whose the density distribution is relatively high. However currently, according to the target management guideline of greenhouse gas and energy, the continuous measuring method to calculate greenhouse gas emission is applied only to $CO_2$. Therefore for reliable greenhouse gas emission calculation it would be necessary to apply continuous measuring to calculate $Non-CO_2$ gas emission.

• 대한수학회논문집
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• 제16권2호
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• pp.287-290
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• 2001

Let X$_1$, X$_2$, … be a sequence of independent and identically distributed random variables with continuous cumulative distribution function F(x). X(sub)j is an upper record value of this sequence if X(sub)j > max {X$_1$, X$_2$, …, X(sub)j-1}. We define u(n) = min {j│j > u(n-1), X(sub)j > X(sub)u(n-1), n $\geq$ 2} with u(1) = 1. Then F(x) = 1 - e(sup)-x/c, x > 0 if and only if E[X(sub)n(n+1) - X(sub)u(n)│X(sub)u(m) = y] = c or E[X(sub)u(n+2) - X(sub)u(n)│X(sub)u(m) = y] = 2c, n $\geq$ m+1.

• Child Health Nursing Research
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• 제20권3호
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• pp.225-235
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• 2014

목적 본 연구는 국내외 연구의 체계적 문헌고찰을 통해 미숙아무호흡에 대한 nCPAP의 효과를 재확인하고 nIPPV 중 nSIPPV를 적용한 연구들을 구별하여 효과 차이가 있는지 확인해보고자 한다. 본 연구의 결과를 토대로 고위험신생아 간호전략을 위한 기초적인 자료를 제공하기 위해서이다. 방법 본 연구에서는 1970년 1월부터 2013년 9월까지 미숙아 무호흡증을 대상으로 nCPAP를 제공하고 그 효과를 확인한 연구를 대상으로 검색하였다. 영문 검색어는 'preterm infant', 'prematurity', 'nCPAP', 'apnea', 'trial' 이었으며 국문검색어는 '미숙아', '무호흡', '무호흡중재'로 검색하였다. 총 13편의 논문분석을 위하여 코딩의 준거분석틀에 따라 자료코딩을 하였다. 자료의 코딩에 따른 준거분석틀은 다음과 같다. 먼저 각 연구 특성에 따른 자료의 코딩은 연구자, 게재연도, 표본크기, 중재방법, 중재시간, 주요결과, 적용시간, 실험설계의 편향 유형을 조사하여 제시하였다. 코딩된 자료는 신뢰구간 95%, 통계적 유의수준 5%로 정하며 이용된 프로그램은 STATA 10.0을 이용하였다. 결과 nCPAP의 무호흡감소의 효과와 nIPPV의 차이는 -0.11 (95% CI [-0.64, 0.42])로 유의한 차이가 검증되지 않았다(Z=0.41, p=.680). 그러나 nCPAP와 nSIPPV의 효과차이는 결합추정치 -0.44 (95% CI [-0.81, -0.07)로 nSIPPV가 미숙아무호흡 감소에 효과가 있는 것으로 나타났다(Z=2.35, p=.019). nCPAP의 호흡기치료중지 성공에 대한 효과를 메타분석 한 결과 1.60 (95% CI [0.70, 3.63])이었으며 nIPPV와 차이가 검증되지 않았다(Z=1.12, p=.268). 그러나 nSIPPV는 nCPAP에 비해 결합추정치는 3.94 (95% CI [1.74, 8.90])로 호흡기치료 중지에 효과가 있는 것으로 나타났다(Z=3.29, p=.0001). 결론 미숙아의 무호흡감소와 호흡기치료의 단축을 위해 nCPAP와 nIPPV 중 nSIPPV의 효과를 확인하였으며 본 연구결과를 기초로 임상에서 활용 가능한 미숙아 호흡관리 프로토콜 개발을 위해 지속적인 연구들이 진행되어져야 할 것이다.

• 충청수학회지
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• 제15권2호
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• pp.47-56
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• 2003

This note is concerned with some properties of fixed points and periodic points. First, we have constructed a generalized continuous function to give a proof for the fact that, as the reverse of the Sharkovsky theorem[16], for a given positive integer n, there exists a continuous function with a period-n point but no period-m points wherem is a predecessor of n in the Sharkovsky ordering. Also we show that the composition of two transcendental meromorphic functions, one of which has at least three poles, has infinitely many fixed points.

• 대한안전경영과학회지
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• 제4권3호
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• pp.35-43
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• 2002

For the unconfined vapor cloud explosion accident by the continuous release of gas-liquid flow of various saturated liquids in a vessel at ground level, overpressures were estimated and analyzed with various release conditions and materials by TNT equivalency model with vapor dispersion. We found that at same release conditions, overpressure showed n-heptane > xylene > n-hexane > toluene > n-heptane > benzene, respectively and that overpressure was increased with increasing the hole diameter and the storage pressure, but it was increased with decreasing the wind speed, the interested distance, and the vessel thickness.

• 한국전자파학회논문지
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• 제16권3호
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• pp.286-292
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• 2005

인터리브 된 레일리 페이딩 채널에서 비동기식 N-심볼 연속 위상 주파수 변조(Continuous Phase Frequency Shift Keying, CPFSK) 방식을 위한 비트 인터리브 된 부호화 변조(Bit Interleaved Coded Modulation, BICM) 시스템을 설계하고 성능을 분석 하였다. 본 논문에서는 BICM의 설계와 성능 분석을 위하여 비동기식 N-심 볼 CPFSK의 기하학적 등가 정규 제곱 거리(Equivalent Normalized Squared Distance, ENSD)를 사용하였다. 특히 비동기식2-심볼 4진 CPFSK 방식을 위한 BICM 시스템을 설계하였으며, 이 시스템 의 성능을 ENSD를 이용하여 분석하고, 모의실험을 통해 검증하였다.