• 한국식품과학회지
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• 제51권3호
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• pp.227-236
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• 2019

Antioxidant activity in water and ethanol extracts of dried Lycium chinense fruit, as a result of the total phenolic and tannin content, was measured using a number of chemical and biochemical assays for radical scavenging and inhibition of lipid peroxidation, with the analysis being extended by applying a bootstrapping statistical method. Previous statistical analyses mostly provided linear correlation and regression analyses between antioxidant activity and increasing concentrations of phenolics and tannins in a concentration-dependent mode. The present study showed that multiple component or multivariate analysis by applying multiple regression analysis or regression planes proved more informative than linear regression analysis of the relationship between the concentration of individual components and antioxidant activity. In this paper, we represented the multivariate analysis of antioxidant activities of both phenolic and tannin contents combined in the water and ethanol extracts, which revealed the hidden observations that were not evident from linear statistical analysis.

• 한국농공학회논문집
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• 제52권5호
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• pp.27-35
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• 2010

The characteristics of delivered nutrient loads were analyzed and the regression equations to estimate delivery ratios of nutrients (TN and TP) were developed using HSPF simulation results at six subwatersheds within the Bochung A unit watershed during 1998-2007. TN delivery ratio was higher than TP delivery ratio because significant amounts of TP was considered to be attached at soil as ${PO_4}^-$ during delivery process from discharged point of nutrient source to main stream. As a results of correlation analysis, factors related to geomorphic characteristics had not statistical correlation with TN and TP delivery ratios. TN loading rate from living and specific stream flow had statistical negative and positive correlation, respectively, with TN delivery ratio. TP loading rates from all sources and from land cover and specific stream flow had statistical negative, negative and positive correlation, respectively. The specific stream flow represents the most strong correlation with nutrient delivery ratios. The regression equations to estimate delivery ratios for TN and TP were developed by including statistical correlated factors and showed high efficiency of 0.98 and 0.95 of coefficient of determination for TN and TP, respectively.

• Communications for Statistical Applications and Methods
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• 제19권4호
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• pp.527-536
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• 2012

In this paper we analyze the effect of circular variables such as wind direction, time and month on the ozone level. In particular, we examined the effect of wind direction by exploratory data analysis methods and provide the correlation and regression analyzes in the cases including all circular explanatory variables. In the analysis, we convert time and month variables to circular variables and analyze the effect of these variables on regression analysis; in addition, we also consider circular-circular regression. We used weather condition and air pollution data collected from Dongdaemoon district of Seoul in 2007.

• 한국치위생학회지
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• 제17권6호
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• pp.1215-1223
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• 2017

Objectives: The purpose of this study was to investigate the correlation between dietary calcium (Ca) and phosphorus (P) intake with DMFT (Decayed Missing Filled Teeth) among Korean schoolchildren. Methods: Data of 1,529 schoolchildren were derived from the Sixth Korean National Health and Nutrition Examination Survey, which was conducted from 2013 to 2015. Sociodemographic, oral health behavior, and dietary factors were collected as independent variables. The DMFT was used as a dependent variable. The chi-square test and logistic regression analysis were performed to identify the correlation between dental caries and the other variables. Results: Multiple logistic regression analysis showed that DMFT was correlated with sex, age, and daily P intake. Conclusions: Adequate intake of phosphorus may have a positive effect in preventing dental caries in schoolchildren. Therefore education on increasing phosphorus intake, including raised awareness through provision of dietary guidelines, will be needed.

• 한국연초학회지
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• 제3권2호
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• pp.115-122
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• 1981

Data for this study were obtained from Burley 21 (Nicotiana tabacum L.) grown under various densities on the field in 1978 and 1979 at the Jeonju Experiment Station, Korea Ginseng & Tobacco Research Institute. Interrelations between yield and its components were statistically studied by correlation, regression, and pathway analysis. Correlation of yield with plant population was significant and positive. Quadratic functions for yield vs. plant population and the length of the largest leaf were fitted to the data. Multiple recession equation between yield and its components (leaf number ($X_1$), a leaf area ($X_5$), weight per unit leaf area ($X_9$), plant population ($X_14$)), was significant at the 5% level. Measuring the relative importance of its components on yield, plant population was 49.5%, weight per unit leaf area 25.3%, a leaf 15.6%, and leaf number 9.8%.

• Plant Resources
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• 제3권3호
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• pp.206-210
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• 2000

A total of 20 soybean recommended varieties which were developed until late 1980's in Korea was evaluated at Suwon. Comprehensive evaluation and correlation analysis were conducted on the agronomic characters. Great variations were found in these genotypes for branch number, pod number, and grain yield per plant. The variation in number of pods/plant ranged from 53 to 164, and in grain yield from 25.9 to 68.8 g. The coefficient of variation for most of the characters had a wide range. In correlation coefficient, grain yield per plant showed a positive phenotypic association with weight of pods, pod number of branches, and weight of stem. Multiple regression analysis was done to formulate selection criteria. It indicated that stout and medium-stature genotypes with more branches, resulting in varieties with more pods per plant but with medium-size seeds are available to obtain high-yielding varieties.

• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.215-221
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• 1999

The object of the thermal error compensation system in machine tools is improving the accuracy of a machine tool through real time error compensation. The accuracy of the machine tool totally depends on the accuracy of thermal error model. A thermal error model can be obtained by appropriate combination of temperature variables. The proposed method for optimal variable selection in the thermal error model is based on correlation grouping and successive regression analysis. Collinearity matter is improved with the correlation grouping and the judgment function which minimizes residual mean square is used. The linear model is more robust against measurement noises than an engineering judgement model that includes the higher order terms of variables. The proposed method is more effective for the applications in real time error compensation because of the reduction in computational time, sufficient model accuracy, and the robustness.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.476-481
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• 2000

A linear correlation, by the stepwise multiple regression analysis, was found between the sensory test of Sigumjang aroma and the gas chromatographic data which were transformed with logarithm. GC data is the most objective method to evaluate Sigumjang aroma. A multiple correlation coefficient and a determination coefficient of more than 0.9 were obtained at the 9th and 13th steps, respectively. At step 31, the coefficient of determination level of 0.95 was attained. The accuracy of its estimation became higher as the number of the variables entered into the regression model increased. Over 90% of the Sigumjang aroma was explained by 13 compounds indentified on GC. The contributing proportion of the peak 26 was the highest followed by peaks 57 (9.27%), 29 (7.51%), 54 (6.01%), 8 (5.99%), 49 (4.97%), and 13 (4.11%).

• 한국물환경학회지
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• 제39권4호
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• pp.261-268
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• 2023

The benthic macroinvertebrates index (BMI) was developed based on the 5-day biochemical oxygen demand (BOD₅), which is the amount of biodegradable organic matter in stream water. However, benthic macroinvertebrates mainly live in the streambed substrate and are affected by the interaction of water quality and substrate. This study was conducted to examine the interactive relationship between water quality items (BOD₅, total phosphorus (TP), total suspended solids (TSS)) and substrate with BMI by performing statistical analyses (four-way analysis of variance, Pearson's correlation analysis, partial correlation analysis and multiple regression analysis). The data used in the analyses were collected from 19,915 sampling units at 1,937 sites in South Korea from 2010 to 2020. The interaction effect between BOD₅ and substrate types was confirmed through a four-way analysis of variance. Partial correlation analysis and multiple regression analysis estimated the degree of influence on the change in BMI value in the order of mean grain size of the substrate as (𝜱_m) > BOD₅ > TP > TSS. BMI can be regarded as an index that evaluates the comprehensive effects of water quality and streambed status, although it is an index that was developed based on the amount of biodegradable organic matter in a water column.

• 자원ㆍ환경경제연구
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• 제33권1호
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• pp.59-86
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• 2024

최근 도시가스 수요에 관한 연구는 광역별, 지역별로 각 지역 특성을 반영하여 미시적 관점에서 접근하는 경향이 확대되는 추세이다. 이때 인접지역이 가지는 사회구조의 유사성과 공급 인프라의 밀집성은 지역 간 미시적인 관계를 가지는 군집성과 공간적 상관성을 유도한다. 이에 민수용 도시가스 수요에 대해 34개 도시가스사의 관할지역을 기준으로 총 54개의 지역으로 구분한 후 공간 상관성을 분석한 결과 전역적, 국지적 관점에서 양의 공간적 상관성이 있음을 확인할 수 있었다. 본 연구에서는 2014년 1월부터 2022년 12월까지 54개 지역에 대한 민수용 도시가스 수요를 패널데이터로 구성하여 공간패널회귀분석과 일반 패널회귀분석을 비교하였으며, 오차에 공간적 효과가 존재하는 공간오차모형(SEM)이 가장 적합한 모형임을 도출할 수 있었다. 이는 한 지역의 민수용 도시가스 수요가 인접지역과 유의한 관계가 있음을 확인함으로써 정책적, 실무적 시사점을 제시한다.