• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.33 no.8
• /
• pp.813-818
• /
• 2009

Design analysis and computer experiments (DACE) model is widely used to express efficiently nonlinear responses in the field of engineering design. As a DACE model, kriging model can approximately replace a simulation model that is very expensive or highly nonlinear. The kriging model is composed of the summation of a global model and a local model representing deviation from the global model. The local model is determined by correlation coefficient with the pre-sampled points, where the accuracy and robustness of the kriging model depends on the selection of proper correlation coefficients. Therefore, to achieve the robust kriging model, the range of the correlation coefficients is explored with respect to the degrees of the global model. Based on this study we propose the proper orders of the global model and range of parameters to make accurate and robust kriging model.

• Journal of the Speleological Society of Korea
• /
• v.15 no.16
• /
• pp.38-60
• /
• 1987

There are BOD(Biochemical Oxygen Demand) and COD(Chemical Oxygen Demand) in the date of the water pollution in the pollution analysis, BOD and COD analysis the result of the analysis. The computer developed the program in the analysis. Went by BOD, the relation conversion equation type of COD, the control chart, the standard deviation, and the coefficient of correlation etc.. for the purpose of the development of the program. There is a purpose by which it is what coefficient of correlation in the development of this program or not if the value (X and Y) of unknow is understood. In the future, if this program is applied the utilization to not only the data is analyzed about the water pollution but also a lot of fields is proposed.

• The Journal of Korean Obstetrics and Gynecology
• /
• v.24 no.1
• /
• pp.74-86
• /
• 2011

Objectives: The purpose of this study was to examine correlation between Heart Rate Variability and urine analysis of women with urinary disturbance. Methods: We studied 34 patients visiting ${\bigcirc}{\bigcirc}$hospital from January 2010 to September 2010. The subjects were categorized in two groups, symptom group (n=11) and no symptom group(n=23). We studied the difference of Heart Rate Variability and urine analysis between two groups by Student T-test and correlation between Heart Rate Variability and urine analysis by Pearson's correlation coefficient test using SPSS for windows (version 17.0). Results: Occult blood of symptom group was significantly higher than no symptom group. SDNN, TP and HF of symptom group was significantly lower than no symptom group. Occult blood and SDNN, occult blood and RMS-SD, occult blood and HF significantly showed negative correlation coefficient. pH and TP, pH and LF significantly showed positive correlation coefficient. Conclusion: The results suggest that urinary disturbance can be related to decreased activity of autonomic nervous system. Also urine from women with urinary disturbance tend to show higher occult blood.

• Investigative Magnetic Resonance Imaging
• /
• v.21 no.3
• /
• pp.171-176
• /
• 2017

Purpose: To compare different MR sequences for quantification of gadolinium concentration. Materials and Methods: Gadolinium contrast agents were diluted into 36 different concentrations. They were scanned using gradient echo (GRE) and ultrashort echo time (UTE) and R1, $R2^*$ and phase values were estimated from collected data. For analysis, ROI masks were made for each concentration and then ROI value was measured by mean and standard deviation from the estimated quantitative maps. Correlation analysis was performed and correlation coefficient was calculated. Results: Using GRE sequence, R1 showed a strong linear correlation at concentrations of 10 mM or less, and $R2^*$ showed a strong linear correlation between 10 to 100 mM. The phase of GRE generally exhibited a negative linear relationship for concentrations of 100 mM or less. In the case of UTE, the phase had a strong negative linear relationship at concentrations 100 mM or above. Conclusion: R1, which was calculated by conventional GRE, showed a high performance of quantification for lower concentrations, with a correlation coefficient of 0.966 (10 mM or less). $R2^*$ showed stronger potential for higher concentrations with a correlation coefficient of 0.984 (10 to 100 mM), and UTE phase showed potential for even higher concentrations with a correlation coefficient of 0.992 (100 mM or above).

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.25 no.3
• /
• pp.384-388
• /
• 2021

Currently, whether in a domestic or international sphere, many small businesses are suffering due to COVID-19. The grim reality is that several businesses are shutting down. While the national disaster relief grant was used to contain the damages by encouraging consumer spending, it has become difficult to prevent closures of small businesses. As of September 2020, more than 20,000 stores have closed in Seoul due to the COVID-19 pandemic. There has also been an increase in the number of people with depression caused by the COVID-19 blues. This issue is not only confined to Seoul in the Republic of Korea, but is influencing all other areas affected by the pandemic. As the number of COVID-19 patients increase, the number of open stores is decreasing steadily. The analysis of the correlation coefficient of Pearson, Spearman, and Kendall suggests a negative correlation between the number of COVID-19 patients and the number of stores in business.

• Journal of the Society of Naval Architects of Korea
• /
• v.40 no.5
• /
• pp.1-9
• /
• 2003

To predict the powering performance of full scale ships from the towing tank tests, resistance, propeller open water and self-propulsion tests are conducted. Model tests inevitably include the experimental error defined as the sum of two types of uncertainties, bias and precision errors. The induced errors in each element of model test are propagated through various routes and correlated with one another. The correlation coefficients are very important in the uncertainty analysis. The coefficient gives a direction(increase or decrease) for a value of error in individual elements. If the coefficient is not used accurately, the error bounds of the individual elements are overestimated or underestimated. In this study, the new methodology is applied to the uncertainty analysis of HMRI's towing tank tests, thus error bounds of each element is suggested and verified by several repetitive experiments.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10b
• /
• pp.656-661
• /
• 1998

This paper presents a method of statistical analysis and sensitivity analysis of creep and shrinkage effects in PSC box girder bridges. The statistical and sensitivity analyses are performed by using the numerical simulation of Latin Hypercube sampling. For each sample, the time-dependent structural analysis is performed to produce response data, which are then statistically analyzed. The probabilistic prediction of the confidence limits on long-term effects of creep and shrinkage is then expressed. Three measures are examined to quantify the sensitivity of the outputs to each of the input variables. These are rank correlation coefficient(RCC), partial rank correlation coefficient(PRCC) and standardized rank regression coefficient(SRRC) computed on the ranks of the observations. Probability band widens with time, which indicates an increase of prediction uncertainty with time. The creep model uncertainty factor and the relative humidity appear as the most dominant factors with regard to the model output uncertainty.

• Journal of the Korean Data and Information Science Society
• /
• v.22 no.1
• /
• pp.57-64
• /
• 2011

The Korea Sport Talent Search System (KOSTASS) can easily assess potential of Korean youth in 23 sport events and to identify sports talents who have high potential in track-and-field, swimming and gymnastics. The purpose of present study was to analysis relationship between sports talent test scores and KOSTASS scores. Physique, physical fitness, motor ability and physiological tests including skeletal age were administrated. Data of 201 elementary students who aged 7 to 12 living in Seoul area were collected. For pure association analysis, Pearson correlation coefficient and partial correlation coefficient are used and stepwise regression analysis is used for selecting important sports talent test scores. The results show that skeletal age, weight, chest circumference, 50-meter run, and half-squat jump have relatively low impact on six KOSTASS scores. The KOSTASS program would contribute to identify talented youth in sports among Korean youth population and success for international sports competition.

• Journal of Environmental Science International
• /
• v.15 no.9
• /
• pp.887-895
• /
• 2006

Through this research of the analysis on the frequency flood discharges regarding basin property factors, a linear regression system was introduced, and as a result, the item with the highest correlation with the frequency flood discharges from Nakdong river basin is the basin area, and the second highest is the average width of basin and the river length. The following results were obtained after looking at the multi correlation between the flood discharge and the collected basin property factors using the data from the established river maintenance master plan of the one hundred twenty-five rivers in the Nakdong river basin. The result of analysis on multivariate correlation between the flood discharges and the most basic data in determining the flood discharges as basin area, river length, basin slope, river slope, average width of basin, shape factor and probability precipitation showed more than 0.9 of correlation in terms of the multi correlation coefficient and more than 0.85 for the determination coefficient. The model which induced a regression system through multi correlation analysis using basin property factors is concluded to be a good reference in estimating the design flood discharge of unmeasured basin.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.12 no.2
• /
• pp.161-169
• /
• 2000

The experiment was conducted to obtain correlation of the air side heat transfer coefficient of wire-on-tube type heat exchanger using the single layer heat exchanger. The correction factors to Zhukauskas correlation was driven from the experimental results. The numerical analysis and experiment with several wire-on-tube type condensers to validate the correction factors are also peformed. The maximum discrepancy between experimental results and the numerical results using the correction factors of this study and Zhukauskas correlation is 10.0%, while that of reference correlation is 47.5%.