• 한국대기환경학회지
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• 제8권4호
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• pp.213-220
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• 1992

Simple correlation analysis, factor analysis, and multi-variate analysis have been performed to analyze the relationship between air pollution and meteorological factors for air pollution and meteorological data measured at Kwanghwamun in Seoul during the period of one year(January 1990 $\sim$ December 1990). As a result of simple correlation and factor analysis, $SO_2$, TSP and CO concentrations have shown high negative correlation with temperature and among these indicating that these are related with pollutant emission trend based upon heating fuel usage. Ozone has a good corrleation with solar radiation and relative humidity to have a closed relation with $O_3$ generation reaction mechanism. The result of multi-variate correlation analysis shows that the concentration of $SO_2$ and CO are adequate for correlation model with ambient temperature and wind speed and $O_3$ concentrations are adequate for that with solar radiation and wind speed. $SO_2$ and CO levels are considered to be affected first of all by heating fuel usage as a emssion source and wind speed as a dispersion effect. The $SO_2$ concentration in the condition that the temperature fall below zero is explained by multilicative model with wind speed, only one variable.

• Journal of the Korean Data and Information Science Society
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• 제24권3호
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• pp.651-658
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• 2013

For the marginal model and generalized estimating equations (GEE) method there is important full covariates conditional mean (FCCM) assumption which is pointed out by Pepe and Anderson (1994). With longitudinal data with time-varying stochastic covariates, this assumption may not necessarily hold. If this assumption is violated, the biased estimates of regression coefficients may result. But if a diagonal working correlation matrix is used, irrespective of whether the assumption is violated, the resulting estimates are (nearly) unbiased (Pan et al., 2000).The quadratic inference functions (QIF) method proposed by Qu et al. (2000) is the method based on generalized method of moment (GMM) using GEE. The QIF yields a substantial improvement in efficiency for the estimator of ${\beta}$ when the working correlation is misspecified, and equal efficiency to the GEE when the working correlation is correct (Qu et al., 2000).In this paper, we interest in whether the QIF can improve the results of the GEE method in the case of FCCM is violated. We show that the QIF with exchangeable and AR(1) working correlation matrix cannot be consistent and asymptotically normal in this case. Also it may not be efficient than GEE with independence working correlation. Our simulation studies verify the result.

• 한국통신학회논문지
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• 제35권4C호
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• pp.321-328
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• 2010

본 논문에서는 이동 통신에서 주로 쓰이는 하향/상향링크(downlink/uplink)처럼 상호 간의 상관관계가 존재하는 두 개의 채널에 대한 시뮬레이션 방법을 제안한다. 제안된 방법은 기존 방법의 문제점인 채널 간의 상관관계가 수학적 기준모델과 일치하지 않는 점을 개선한 방법이다. 레일리 페이딩 채널 시뮬레이션 모델은 유한개의 삼각함수의 합을 이용한 SOS(Sum-of-Sinusoids) 방법을 사용하였다. 이 방법은 페이딩 신호의 샘플들을 발생할 때 효율적인 방법으로 알려져 있으며 수학적 기준모델에 대한 정확한 시뮬레이션 결과를 얻을 수 있다. 제안된 모델은 기준모델의 이론적인 상관관계와 시뮬레이터로부터 얻은 채널 간의 상관관계의 오차를 줄이기 위해 MSE를 최소화하는 방식을 이용하면서 평균전력을 이론치와 같게 유지하는 방법이다. 실험결과를 통해 제안한 방법이 기존의 방법보다 기준모델의 수학적 상관관계를 더욱 정확히 모사하는 것을 확인하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권4호
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• pp.2094-2112
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• 2019

Focusing on the issue that the conventional Kernel Correlation Filter (KCF) algorithm has poor performance in handling scale change and obscured objects, this paper proposes an anti-occlusion and scale adaptive tracking algorithm in the basis of KCF. The average Peak-to Correlation Energy and the peak value of correlation filtering response are used as the confidence indexes to determine whether the target is obscured. In the case of non-occlusion, we modify the searching scheme of the KCF. Instead of searching for a target with a fixed sample size, we search for the target area with multiple scales and then resize it into the sample size to compare with the learnt model. The scale factor with the maximum filter response is the best target scaling and is updated as the optimal scale for the following tracking. Once occlusion is detected, the model updating and scale updating are stopped. Experiments have been conducted on the OTB benchmark video sequences for compassion with other state-of-the-art tracking methods. The results demonstrate the proposed method can effectively improve the tracking success rate and the accuracy in the cases of scale change and occlusion, and meanwhile ensure a real-time performance.

• 무역학회지
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• 제47권1호
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• pp.99-114
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• 2022

This paper analyzed the dynamic conditional correlation between the carbon emission trading prices of Korea, China, EU, New Zealand. This paper was analyzed using the daily data of carbon emission trading prices of each country from January 12, 2015 to January 13, 2021 using the DCC-GARCH model. Summarizing the research results, first, the dynamic conditional correlation between carbon emission trading prices in the EU, Korea, and China, excluding New Zealand, was strong, indicating that there was a co-movement phenomenon. Second, it was found that carbon emission trading prices in major countries have a stronger tendency to co-movement due to global shocks. Third, it appears that the dynamic conditional correlation between the carbon emission trading prices of Korea and China is gradually strengthening. This study confirmed that the co-movement between carbon emission trading prices in Korea and other countries gradually intensified as time passed. In particular, it is meaningful in suggesting the implication that the phenomenon of co-movement between carbon emission trading prices in Korea and China is gradually intensifying.

• Journal of the Korean Data and Information Science Society
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• 제4권
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• pp.131-136
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• 1993

We shall consider the trends of correlation coefficient between the smallest and largest observations in the Weibull model in the presence of an unidentified outlier, and derive the density functions of order statistics by the permanent theory.

• Communications for Statistical Applications and Methods
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• 제8권1호
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• pp.29-37
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• 2001

In this paper, we consider the second order probability matching criterion for the ratio of the variance components under the one-way random effect model. It turns out that among all of the reference priors given in Ye(1994), the only one reference prior satisfies the second order matching criterion. Similar results are also obtained for the intraclass correlation as well.

• Bulletin of the Korean Chemical Society
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• 제14권1호
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• pp.110-112
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• 1993

Molecular reorientation of oblate symmetric top molecules in the presence of internal rotation is investigated and an analytic expression for the overall reorientational correlation time is obtained. The overall reorientation of the symmetric top is treated by the anisotropic rotational diffusion and the internal rotation is analyzed by employing a model which describes jumps between several discrete states with different lifetimes. The lifetimes thus obtained can be compared with the internal angular momentum correlation time which appears when the internal rotation is treated by a modified extended rotational diffusion model.

• 대한원격탐사학회지
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• 제34권6_2호
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• pp.1251-1260
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• 2018

항공영상으로 제작한 고품질의 해빙표면모델은 인공위성 기반 원격탐사 기술 개발을 위한 현장자료 뿐만 아니라 북극 해빙의 정밀한 형상학적 변동 특성 분석에도 효과적으로 사용될 수 있다. 그러나 해빙 표면의 부족한 텍스쳐 정보는 영상정합을 어렵게 만드는 요인으로 작용한다. 이에 본 논문에서는 고품질 해빙표면 모델 생성을 위한 일환으로 균질한 해빙 표면에 대한 정합비용함수들의 성능 비교 분석을 수행한다. 정합비용함수로는 영상 도메인의 SSD(sum of squared differences), NCC(normalized cross-correlation), ZNCC(zero-mean normalized cross-correlation), 주파수 도메인의 PC(phase correlation), OC(orientation correlation), GC(gradient correlation)를 분석하였다. 텍스쳐 정보량에 따른 정합 성능을 보다 명확하고 객관적으로 분석하기 위해 객체 공간 기반 정합 기법의 원리를 바탕으로 하는 새로운 평가 방법을 도입하였다. 실험결과는 해빙 표면과 같이 텍스쳐 정보가 희박한 지역에 대해서는 정합 지역에 따라 적합한 크기의 탐색창을 가변적으로 적용해야만 정합의 신뢰성 및 정확도 확보가 가능함을 보여주었다. 정합비용함수들 사이에서는 NCC와 ZNCC가 텍스쳐 정보 변화에 대해서 가장 우수한 성능을 나타냈다.

• 한국지리정보학회지
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• 제4권1호
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• pp.57-66
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• 2001

본 연구에서는 도시표면온도를 추출하기 위하여 다시기 Landsat TM band 6 영상을 이용하여 과학기술부의 4가지 모델 즉 two-point linear model, linear regression model, quadratic regression model, cubic regression model에 대하여 각각 공간분석을 실시하였으며 그 결과를 AWS(automatic weather station) 관측자료와 상관 및 회귀분석 함과 동시에 GIS 공간분석 기법을 이용하여 도시 표면온도의 공간적 분포특성을 규명하였다. Landsat TM band 6으로부터 추출된 표면온도를 기초로 하여 토지피복별 표면온도 분포를 분석한 결과 도시 및 나지 지역이 가장 높은 온도분포대를 형성하고 있었으며, 표면온도와 NDVI간의 상관분석결과 평균 -0.85 정도의 음의 상관성을 확인할 수 있었다. 이와 같은 결과는 향후 기상환경 특성을 고려한 도시계획수립에 있어 중요한 인자로 작용할 것으로 사료된다.