• Earthquakes and Structures
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• v.8 no.5
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• pp.957-976
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• 2015

Recently, two energy-based response parameters, i.e., the absolute and the relative elastic input energy equivalent velocity, have been receiving a lot of research attention. Several studies, in fact, have demonstrated the potential of these intensity measures in the prediction of the seismic structural response. Although some ground motion prediction equations have been developed for these parameters, they only provide marginal distributions without information about the joint occurrence of the spectral values at different periods. In order to build new prediction models for the two equivalent velocities, a large set of ground motion records is used to calculate the correlation coefficients between the response spectral values corresponding to different periods and components of the ground motion. Then, functional forms adopted in models from the literature are calibrated to fit the obtained data. A new functional form is proposed to improve the predictions of the considered models from the literature. The components of the ground motion considered in this study are the two horizontal ones only. Potential uses of the proposed equations in addition to the prediction of the correlation coefficients of the equivalent velocity spectral values are shown, such as the prediction of derived intensity measures and the development of conditional mean spectra.

• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.241-246
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• 2007

The present paper dealt with an experimental study of boiling heat transfer characteristics of $CO_2$. Heat transfer coefficients of the refrigerant flow inside horizontal smooth microchannel were obtained with inner tube diameter of 0.3mm and length of 300mm. The direct electric heating method was applied for supplying the heat uniformly to the refrigerant. The experiments were conducted with $CO_2$ purity of 99.99%, at saturation temperature of $10^{\circ}C$, mass flux ranges of $300{\sim}900\;kg/m^2s$, and heat flux ranges of $15{\sim}45\;kW/m^2$. While heat transfer coefficient increased with the increase of heat flux in the low quality region, the heat transfer coefficient decreased with the increase of quality in the high quality region. The heat transfer coefficients were compared with seven existing correlations with the Gungor-Winterton's(1986) correlation gave the best prediction. A new corelation to predict the two-phase flow heat transfer coefficient was developed based on the Chen(1966) correlation. The new correlation predicted the experimental data well with a mean deviation of 9.69% and average deviation of -3.03%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.5
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• pp.426-430
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• 1994

To establish the proper size of seedling of A. gigas, different weight of seedlings were used for this study. Agronomic characters including plant height, number of leaf, leaf length, number of inflorescence, fresh weight and rate of bolting of the aerial parts, root length, root diameter, number of lateral root and root weight of the underground parts were determined and correlation coefficients among them were estimated. Growth of A. gigas showed the significant vigor for all the characters of the aerial parts along with increasing of seedling weight, but root weight in yield decreased in proportion to increasing of seedling weight due to lignification of the root tissue. When the smaller seedlings were transplanted, bolting rates decreased to about 16% as compared with the traditional size of seedlings. Correlation coefficients between aerial and root characters in A. gigas were negative, and the characters such as plant height, number of leaf, number of inflorescence and fresh weight per plant showed highly significant correlation with the rate of bolting which is one of the characters having great influence on yield.

• Journal of Community Nutrition
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• v.6 no.1
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• pp.35-41
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• 2004

Cardiovascular disease has the highest mortality rate in South Korea. Previous studies have reported that serum cholesterol level relates to intake of dietary fat and cholesterol. Therefore, in this study we developed a semiquantitative food frequency questionnaire (FFQ) for Koreans with a high-risk of hypercholesterolemia and to validate the FFQ. Semiquantitative FFQ, which includes 160 food items, reflects intakes of energy, fat, saturated fatty acid (SFA), monounsaturated fatty acid (MUPA), polyunsaturated fatty acid (PUPA) and cholesterol. We chose food items from the previous study of our research group (Suh 1999) which reported a nutritional status of Korean adults with normocholesterolemia, borderline and hypercholesterolemia. To validate the FFQ, we compared the results of the FFQ with those of a 3-day food record using a paired t-test. In addition, we calculated Pearson's and Spearmen's correlation coefficients. Intakes assessed by the FFQ and a 3-day food record were classified into quartile and the degree of agreement was obtained. Fifty-five participants responded for the validation study by completing both the FFQ and a 3-day food record. Pearson's correlation coefficients between estimated intakes by respective methods for energy, fat, SF A, MUPA, PUPA and cholesterol were 0.32,0.41,0.37,0.41,0.37 and 0.21, respectively. Spearman's correlation coefficients of energy, fat, SF A, MUPA, PUPA, cholesterol were 0.31, 0.44, 0.39, 0.46, 0.46, and 0.37, respectively. Nutrient densities in 1000kcal were compared. Pearson's correlation coefficient of cholesterol density increased and other values were similar with original values. The average degree of agreement was 67％ that intakes of energy, fat, SF A, MUPA, PUPA and cholesterol assessed by the FFQ and 3-day food records were classified within the same and the adjacent quartile. On the average, 8％ were misclassified into the extreme opposite quartile. The average of weighted kappa was 0.46. In conclusion, the FFQ developed in this study is considered to be a reliable tool to assess nutrient intakes for Koreans with a risk of hypercholesterolemia because the FFQ reflects the intakes of energy, fat, SFA, MUFA, PUPA, and cholesterol.

• Journal of Preventive Medicine and Public Health
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• v.55 no.3
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• pp.234-242
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• 2022

Objectives: This study assessed the validity and reliability of the Health-related Quality of Life Instrument with 8 Items (HINT-8) in patients with diabetes. HINT-8 is a newly-developed, generic health-related quality of life (HRQoL) instrument. Methods: Three HRQoL instruments-HINT-8, EuroQoL 5-Dimension 5-Level (EQ-5D-5L), and Short Form Health Survey version 2.0 (SF-36v2)-were provided to 300 patients with diabetes visiting a tertiary hospital for follow-up visits in Korea. The HRQoL scores obtained using the HINT-8 were evaluated for subgroups with known differences based on demographics and diabetes-related characteristics (known-group validity). The mean scores of the instruments were compared between groups segmented by their responses to the HINT-8 (discriminatory ability). Correlation coefficients of the HINT-8 with other instruments were calculated (convergent and divergent validity). The Cohen kappa and intra-class correlation coefficient (ICC) were also evaluated (test-retest reliability). Results: The average HINT-8 indexes were lower among women, older, and less-educated subjects. Subjects who did not list any problems on the HINT-8 had significantly higher HRQoL scores than those who did. The correlation coefficients of the HINT-8 with the EQ-5D-5L index and EuroQoL visual analogue scale were 0.715 (p<0.001) and 0.517 (p<0.001), respectively. The correlation coefficients between the HINT-8 index and the scores of 8 domains of the SF-36v2 ranged from 0.478 (p<0.001) to 0.669 (p<0.001). The Cohen kappa values for the HINT-8 ranged from 0.268 to 0.601, and the ICC of the HINT-8 index was 0.800 (95% confidence interval [CI], 0.720 to 0.860). Conclusions: This study showed that the HINT-8 is a valid and reliable HRQoL instrument for patients with diabetes.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.5
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• pp.72-83
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• 2011

In this paper, we propose a method to detect and recover the occluded parts of face images using the correlation between pairs of pixels. In a training stage, correlation coefficients between every pairs of pixels are calculated using the occlusion-free face images. Once a new occluded face image is shown, the occluded area is detected and recovered using the correlation coefficients obtained in the training stage. We compare the performance of the proposed method with the conventional method based on PCA. The results show that the proposed method detects and recovers occluded area with much smaller noises than the conventional PCA based method. Moreover, recovered images by the proposed method were more smooth with reduced blurring effect.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.8
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• pp.1928-1936
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• 1996

In this paper, we propose an adaptive bandwidth allocation algorithm for the transmission of VBR video through ATM Networks. In order to evaluate the required bandwidth for the VBR video, the characteristics of the compressed VBR video generated by the two-layered coder are analyzed with variations in the number of GOP(N), quantizer scale(q), and the number of low-frequency DCT coefficients(.betha.). The two-layer coder which is used to separate from the number of DCT coefficients is designed to transmit the VBR video efficiently. The compressed data generated by the two-layer coder are splitted into the high priority and low priority cells. If congestion is occurred in ATM networks, the minimum image quality is maintained by the high priority cells. The required bandwidth for VBR video is estimated with a prediction algorithm using the scene anframe correlations as well as the statistical properties of the VBR video sources. Strong correlation among the adjacent slices in a frame represents by the scene correlation andstrong correlation among the frames is represented by the frame correlation. The performance of the bandwidth allocation scheme proposed is evaluated in terms of the bandwith utilization, cell loss rate, and SNR with variations in q, n, .betha.. Simulation rewsults shown that the proposed scheme is superior to the conventional methods.

• Journal of Nutrition and Health
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• v.28 no.4
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• pp.282-290
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• 1995

Subcutaneous fat thickness of 74 young male was measured at six sites(biceps, triceps, subscapula, suprailiac, abdomen, thigh). The present study compared caliper with ultrasound measurements for the estimation of body fat. Caliper measurements subcutaneous at six sites had higher coefficient variation than did the ultrasound measures. Caliper measurements subcutaneous at six sites had higher ratio (caliper/ultrasound) than did the ultrasound measures. Compared to other body sites, the correlations between caliper and ultrasound measurements were high for the subscapula(r=0.7327), abdomen(r=0.7355) and thigh (r=0.7207) sites. the correlations between caliper and ultrasound measurements were high for the suprailiac(r=0.6616) site by lean group. the correlations between caliper and ultrasound measurements were high for the abdomen(r=0.7636) site by normal group. The correlations between caliper and ultrasound measurements were high for the subscapula (r=0.8959) and abdomen(r=0.8237) sites by obese group. Ultrasound measurement of biceps(r=-0.4459), abdomen9r=-0.4469), thigh(r=-0.4348) had the highest correlation with body density. Caliper measurement of triceps(r=-0.4017), subscapula(r=-0.4454), abdomen(r=-0.4293) had the highest correlation with body density. Ultasound measurements subcutaneous fat at lean group, obese group had higher coefficients of correlation with body density than did the caliper measurement. Caliper measurements subcutaneous fat at normal group had higher coefficients of correlation with body density than did the ultrasound measures. Ultrasound showed to be superior to the caliper technique in measuring subcutaneous fat of obese persons.

• Journal of agricultural medicine and community health
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• v.49 no.2
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• pp.111-120
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• 2024

Objective: This study aimed to analyze the correlation between factors affecting health risk behaviors of rural residents according to regional scale. Methods: Restricted-access data from the 2016~2021 Korea National Health and Nutrition Examination Survey and the multivariate probit model were used. As for health risk behaviors, smoking, drinking, lack of aerobic exercise, low level of healthy eating index, unvaccination, and non-participation in health examination were considered. Results: Controlling for individuals' socio-demographic characteristics, in general, correlation coefficients between unobservable factors affecting health risk behaviors were significant. However, the magnitude and statistical significance of the correlation coefficients varied by regional scale (dong/eup/myeon). This suggests that rural residents engage in health risk behaviors due to their different characteristics compared with urban dwellers, which also varies by whether residents are located in eup or myeon area. Conclusion: It is necessary to differentiate health care services between urban and rural areas in terms of type of service and programs based on the relationship between unobservable factors affecting each type of health risk behaviors.

• The KIPS Transactions:PartB
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• v.13B no.3 s.106
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• pp.329-336
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• 2006

In this paper, we propose a method of significant term extraction within a document. The technique used is Principal Component Analysis(PCA) which is one of the multivariate analysis methods. PCA can sufficiently use term-term relationships within a document by term-term correlations. We use a correlation matrix instead of a covariance matrix between terms for performing PCA. We also try to find out thresholds of both the number of components to be selected and correlation coefficients between selected components and terms. The experimental results on 283 Korean newspaper articles show that the condition of the first six components with correlation coefficients of |0.4| is the best for extracting sentence based on the significant selected terms.