• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.1721-1726
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• 2004

Heat rate is a representative index to estimate the performance of turbine cycle in nuclear power plant. Accuracy of heat rate calculation is dependent on the accuracy of measurement for plant status variables. Uncertainty of heat rate can be modeled using uncertainty propagation model. We developed practical estimation model of heat rate uncertainty using the propagation and regression model. The uncertainty model is used in the performance analysis system developed for the operating nuclear power plant.

• 한국컴퓨터정보학회논문지
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• 제22권4호
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• pp.115-122
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• 2017

The purpose of this study was to evaluate the effect of job satisfaction on turnover intention and organizational commitment in nurses through a systematic literature review and meta-analysis. For the study purpose, 26 studies were selected through a systematic process of using several databases and used to estimate the effect size of correlation between 3 variables. Meta-analysis was applied by usingcrandom effects model, and effect sizes on three types were calculated. Results are as follows. First, the effect size of correlation between job satisfaction and turnover intention is -.58. Second, the effect size of correlation between job satisfaction and organizational commitment is .77. Third, for the organizational commitment and turnover intention relationship, the effect of correlation is -0.68. Furthermore, publication bias analysis were assessed the results by using the funnel plot, Egger's regression test, fail-safe N, and trim-and-fill test. Based on these results, implications for the study were discussed.

• 한국건설관리학회논문집
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• 제5권1호
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• pp.53-61
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• 2004

리모델링 프로젝트는 기존 자원의 활용이라는 제한조건 안에서 수행되므로 기존 건축물의 구성요소들의 상관관계가 리모델링의 대상과 범위의 선정에 제한조건, 영향요인으로 작용하게 된다. 이러한 리모델링 프로젝트의 특성을 고려하여, 본 연구에서는 리모델링 사업수행시 설계단계에서 건축물 공간을 구성하는 부위의 구성요소간의 상관관계 분석을 통해 시공단계에서 발생하는 다양한 문제로 인한 공기지연, 공사비 증가 등의 문제 발생을 최소화하기 위한 방법으로, 리모델링 설계단계에서 건축시스템의 상관관계를 효율적으로 분석하기 위한 리모델링 건축시스템 상관관계 도식화 모델 및 부위별 적정 대안선정 방법을 제안하였다.

• 천문학논총
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• 제7권1호
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• pp.25-30
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• 1992

Recent redshift surveys suggest that most galaxies may be distributed on the surfaces of bubbles surrounding large voids. To investigate the quantitative consistency of this qualitative picture of large-scale structure, we study analytically the clustering properties of galaxies in a universe filled with spherical shells. In this paper, we report the results of the calculations for the spatial and angular two-point correlation functions of galaxies. With ${\sim}20%$ of galaxies in clusters and a power law distribution of shell sizes, $n_{sh}(R){\sim}R^{-{\alpha}}$, ${\alpha}\;{\simeq}\;4$, the observed slope and amplitude of the spatial two-point correlation function ${\xi}_{gg}(r)$ can be reproduced. (It has been shown that the same model parameters reproduce the enhanced cluster two-point correlation function, ${\xi}_{cc}(r)$). The corresponding angular two-point correlation function $w({\theta})$ is calculated using the relativistic form of Limber's equation and the Schecter-type luminosity function. The calculated w(${\theta}$) agrees with the observed one quite well on small separations (${\theta}{\lesssim}2deg$).

• ETRI Journal
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• 제40권5호
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• pp.570-581
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• 2018

This work analyzes the performance of implementable detectors for the multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) technique under specific and realistic operation system conditions, including antenna correlation and array configuration. A time-domain channel model was used to evaluate the system performance under realistic communication channel and system scenarios, including different channel correlation, modulation order, and antenna array configurations. Several MIMO-OFDM detectors were analyzed for the purpose of achieving high performance combined with high capacity systems and manageable computational complexity. Numerical Monte Carlo simulations demonstrate the channel selectivity effect, while the impact of the number of antennas, adoption of linear against heuristic-based detection schemes, and the spatial correlation effect under linear and planar antenna arrays are analyzed in the MIMO-OFDM context.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2010년도 학술발표회
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• pp.1620-1624
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• 2010

The NLCCA has been applied to analyze the East Asia sea surface temperature (SST) and Korea monthly precipitation, where the eight leading PCs of the SST and the eight PCs of the precipitation during 1973-2007 were inputs to an NLCCA model. The first NLCCA mode is plotted in the PC spaces of the Korea precipitation and the world SST present a curve linking the nonlinear relationship between the first three leading PCs of Korea precipitation and world SST forthright. The correlation coefficient between canonical variate time series u and v is 0.8538 for the first NLCCA mode. And there are some areas' climate variability have higher relationship with Korea precipitation, especially focus on the north of East Sea' climate variability have represented the higher canonical correlation with Korea precipitation, with the correlation coefficient is 0.871 and 0.838. Likewise in Korea, most stations display similarly uniform distributing characteristic and less difference, in particular the inshore stations have display identical distributing characteristic. In correlation variables' scores, the fluctuation and variation trend are also seasonal oscillation with high frequency.

• International Journal of Air-Conditioning and Refrigeration
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• 제9권4호
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• pp.27-36
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• 2001

A new two-phase non-boiling convective heat transfer correlation for turbulent flow $(Re_{SL}>4000)$ in vertical tubes with different fluid flow patterns and fluid combinations was developed using experimental data available from the literature. The correlation presented herein originates from a careful analysis of the major non-dimensional parameters affecting two-phase heat transfer. This model takes into account the appropriate contributions of both the liquid and gas phases using the respective cross-sectional areas occupied by the two phases. A total of 255 data points from three available studies (which included the four sets of data) were used to determine the curve-fitted constants in the improved correlation. The performance of the new correlation was compared with two-phase correlations from the literature, which were developed for specific fluid combinations.

• 한국IT서비스학회지
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• 제12권4호
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• pp.255-265
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• 2013

This paper proposes a DEA-AR model for the efficiency evaluation of the iron ore brands in an integrated steel mill. The input factor is defined as unit cost of each brand based on CIF and two output factors are chosen as Fe and Al which are the important ingredients of iron ore. The relative importance between two output factors is determined by several experts using AHP model. The efficiency of each brand is determined using DEA and DEA-AR models. The negative correlation between the DEA-AR efficiency and the unit cost (CIF) is shown as significant whereas no significant correlation exist between the efficiency and the output factors. Also, the Kruskal Wallis rank sum test shows that there exist efficiency differences among the iron ore types whereas no difference is shown among the countries. The result could be utilized in selecting good brands of iron ores based on the DEA-AR efficiency in an integrated steel mill.

• 산업기술연구
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• 제20권A호
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• pp.203-209
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• 2000

The fluctuation integrals which give useful information in the structure of solution are associated with the mixed direct correlation integral ($C_{12}$) known. Using its weighted arithmetic mean of $C_{11}$ and $C_{22}$ and the activity coefficient model, the fluctuation integrals on solute-solute, solvent-solute, and solvent-solvent can be calculated in the function of mole fraction. In this work, several binary mixtures containing c-hexane were tested and the results on the fluctuation integrals were rather good.

• 대한기계학회논문집B
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• 제28권6호
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• pp.665-671
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• 2004

A mathematical model is presented to predict the frost properties and heat and mass transfer within the frost layer formed on a cold plate. The model consists of the laminar flow equations for air-side and the empirical correlation of local frost density. The correlation of local frost density used in this study is obtained from various experimental conditions by considering frosting parameters. The numerical results are compared with experimental data to validate the model, and agree well with experimental data within a maximum error of 9%.