• Journal of the Korean Physical Society
• /
• v.73 no.12
• /
• pp.1849-1854
• /
• 2018

The present study aims to investigate the feasibility of using a simple nonlinear acoustic method for the assessment of bone status and osteoporosis in trabecular bone. Correlations of linear and nonlinear ultrasound parameters with the apparent bone density were obtained in 32 bovine femoral trabecular bone samples. Highly significant positive correlations were observed between the apparent bone density and the two linear ultrasound parameters, the speed of sound (SOS) and the normalized broadband ultrasound attenuation (nBUA), with Spearman's correlation coefficients of r = 0.85 and 0.77. In contrast, the apparent bone density was found to be negatively correlated with the nonlinear ultrasound parameter introduced in the present study, the logarithmic difference between the power spectrum levels of the fundamental frequency and the second harmonic (PSL1-PSL2), with the highest correlation coefficient of r = -0.92. These results suggest that the PSL1-PSL2, in addition to the SOS and the nBUA, may be useful for the assessment of bone status and osteoporosis.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• v.3 no.1
• /
• pp.23-31
• /
• 2022

The analysis of seven islands in Gogunsan archipelago, Korea with insect fauna and vascular plant flora was carried out based on a field survey conducted in May, July, and September. As a result, a total of 2,817 insect individuals including 264 species and 315 taxa of vascular plant were recorded. Bangchukdo the largest island among the seven islands showed the largest number both insect species and plant taxa. The similarity analysis suggested that the nearness of each island strongly affected the insect fauna and vascular plant flora on each island. In addition, there was significant correlation between the areas of each island and the numbers of insect species (Spearman's correlation coefficient=0.857, P-value=0.014). In the future, the results of this study can be used as data related to island ecology and conservation.

• Korean Journal of Radiology
• /
• v.22 no.2
• /
• pp.243-252
• /
• 2021

Objective: To compare and correlate the findings of intravoxel incoherent motion (IVIM) magnetic resonance (MR) imaging and arterial spin labeling (ASL) imaging in characterizing parotid gland tumors. Materials and Methods: We retrospectively reviewed 56 patients with parotid gland tumors evaluated by MR imaging. The true diffusion coefficient (D), pseudo-diffusion coefficient (D^*), and fraction of perfusion (f) values of IVIM imaging and tumor-to-parotid gland signal intensity ratio (SIR) on ASL imaging were calculated. Spearman rank correlation coefficient, chi-squared, Mann-Whitney U, and Kruskal-Wallis tests with the post-hoc Dunn-Bonferroni method and receiver operating characteristic curve assessments were used for statistical analysis. Results: Malignant parotid gland tumors showed significantly lower D than benign tumors (p = 0.019). Within subgroup analyses, pleomorphic adenomas (PAs) showed significantly higher D than malignant tumors (MTs) and Warthin's tumors (WTs) (p < 0.001). The D^* of WTs was significantly higher than that of PAs (p = 0.031). The f and SIR on ASL imaging of WTs were significantly higher than those of MTs and PAs (p < 0.05). Significantly positive correlation was found between SIR on ASL imaging and f (r = 0.446, p = 0.001). In comparison with f, SIR on ASL imaging showed a higher area under curve (0.853 vs. 0.891) in discriminating MTs from WTs, although the difference was not significant (p = 0.720). Conclusion: IVIM and ASL imaging could help differentiate parotid gland tumors. SIR on ASL imaging showed a significantly positive correlation with f. ASL imaging might hold potential to improve the ability to discriminate MTs from WTs.

• Journal of Preventive Medicine and Public Health
• /
• v.40 no.2
• /
• pp.169-176
• /
• 2007

Objectives : This study was conducted to elicit quality weights for 42 EQ-5D health states with the time trade-off (TTO) method from the general population of South Korea. Methods : We selected the same EQ-5D health states as those in the UK MVH study. The Korean version of EQ-5D questionnaire and TTO method were used for the valuation process. We interviewed 500 people as a representative sample of the general population in Seoul and Gyeonggido. The result was compared with those from UK, Japan, and USA by Spearman's rank correlation and t-test. Results : TTO values for 42 EQ-5D health states and 'unconscious' state were obtained from the general South Korean population. The best one was '11112' state and the worst one was 'unconscious' state. The states worse than death were '33323', '33333', and 'unconscious' states, which had negative TTO values. There was a strong correlation between TTO values of the EQ-5D health states and those of their corresponding states from UK, Japan, and USA (Spearman's correlation coefficient: 0.885, 0.882, and 0.944, respectively, p <0.001). However, absolute TTO values of most EQ-5D health states were significantly different from those of their corresponding states in other foreign studies (UK : 41/42, USA : 32/42, Japan : 15/17). Conclusions : We found that the Korean general population TTO values for EQ-5D health states were different from those of other foreign studies, suggesting that a specific Korean valuation set should be developed and used for economic evaluation studies in South Korea.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1682-1685
• /
• 2005

System algorithms estimated by deterministic input may occur the error between predicted and actual output. Especially, actual system can't predict the exact outputs due to uncertainty and tolerance of input parameters. A single output to a set of inputs has a limited value without the variation. Hence, we should consider various scatters caused by the load assessment, material characteristics, stress analysis and manufacturing methods in order to perform the robust design or estimate the reliability of structure. The system design with uncertainty should perform the probabilistic structural optimization with the statistical response and the reliability. This method calculated the probability distributions of the characteristics such as stress by combining stress analysis, response surface methodology and Monte-Carlo Method and got the probabilistic sensitivity. The sensitivity of structural response with respect to inconstant design variables was estimated by fracture probability. Therefore, this paper proposed the probabilistic reliability design method for fracture of uncorved freight end beam and the design criteria by fracture probability.

• Journal of Astronomy and Space Sciences
• /
• v.30 no.3
• /
• pp.163-168
• /
• 2013

Parameters associated with solar minimum have been studied to relate them to solar activity at solar maximum so that one could possibly predict behaviors of an upcoming solar cycle. The number of active days has been known as a reliable indicator of solar activity around solar minimum. Active days are days with sunspots reported on the solar disk. In this work, we have explored the relationship between the sunspot numbers at solar maximum and the characteristics of the monthly number of active days. Specifically, we have statistically examined how the maximum monthly sunspot number of a given solar cycle is correlated with the slope of the linear relationship between monthly sunspot numbers and the monthly number of active days for the corresponding solar cycle. We have calculated the linear correlation coefficient r and the Spearman rank-order correlation coefficient $r_s$ for data sets prepared under various conditions. Even though marginal correlations are found, they turn out to be insufficiently significant (r ~ 0.3). Nonetheless, we have confirmed that the slope of the linear relationship between monthly sunspot numbers and the monthly number of active days is less steep when solar cycles belonging to the "Modern Maximum" are considered compared with rests of solar cycles. We conclude, therefore, that the slope of the linear relationship between monthly sunspot numbers and the monthly number of active days is indeed dependent on the solar activity at its maxima, but that this simple relationship should be insufficient as a valid method to predict the following solar activity amplitude.

• Journal of the Korean Society of Radiology
• /
• v.14 no.7
• /
• pp.871-879
• /
• 2020

The purpose of this study was to analysis the correlation between kidneys function indicators and these size in ultrasonography. A total of 170 (male:86, female:84) patients of sex and age groups were examined by abdominal ultrasonography. The patients classified as those in their 20's, 30's, 40's, and over 50's. We measured the length, width, and cross-sectional height of the kidneys twice. At this time, the length of these were measured from the maximum upper to the maximum lower pole and the widest width in the same ultrasonography was measured to obtain the cross-sectional area. Other relevant indicators included body surface area, serum creatinine, glomerular filtration rate (GFR), MDRD (Modification of diet in renal disease) and C-G (Cockcroft-Gault). Significant comparisons of differences between relevant factors by age groups and sex were conducted with a one-way distribution analysis. Correlation analysis was also performed between relevant factors by using Pearson and Spearman correlation coefficient. It was defined as meaningful when the p-value was less than 0.05. As a result, the length, the width, and the cross-sectional area of kidneys were correlated with GFR, C-G, MDRD. Therefore, it is expected that the accuracy of diagnosis of kidneys disease will be increased if the relevant indicators are evaluated together rather than measuring only length of these in ultrasonography.

• Journal of the Korean BIBLIA Society for library and Information Science
• /
• v.27 no.3
• /
• pp.51-73
• /
• 2016

This study analyzes on the perception of public librarians about lifelong education tasks in public library using Mann Whitney U-test, Spearman rank-order correlation coefficient, Multiple regression analysis. At the same time, analysis about re-education needs using Analytic Hierarchy Process is conducted. As result, at first, 87% of respondents feel moderate or difficult about lifelong education tasks, especially on planning task. At second, librarians who have qualification about lifelong educator feel easier (P=0.04) than others, in detail, task about lecturer liaison (P=0.04) and planning (P=0.05). Adding that, the career experience and the job difficulty of librarians has negative relationship (R=-0.217). Especially scheduling (R=-0.33) and progressing (R=-0.22) tasks show statistically meaningful. At third, as the result of Multiple regression analysis, tasks about planning (P=0.04) and library marketing (P=0.05) are selected as meaningful elements which effect overall difficulty of life long education job. As final, 91% of librarian need retraining for life long education function, as result of spearman (R=-0.210), the more librarians feels difficult about life long education jobs, the more they need retraining. Anyway, as the result of priority of retraining subjects through AHP technique, user communication (CU P=0.310), planning (PL P=0.246), library marketing (LM P=0.173) are in weight order. CR ratio shows 0.146 with permissible degree.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.17 no.1
• /
• pp.17-27
• /
• 2006

Background and Objectives: Vocal polyp is the most common disease that causes hoarseness and its incidence is increased currently. The purposes of this study are to investigate the correlation between severity of vocal polyp and acoustic parameters and compare these data with those of the normal Korean. Materials and Methods: We analyzed the acoustic parameters of sustained vowel for 70 vocal polyp patients and 20 normal controls. A CSL(computerized speech lab) was used to carry out the analysis of the voice sample and statistical analysis was used Spearman correlation coefficient & t-test. Results: According to the conclusion of correlation analysis, 21 parameters of all the 34 parameters are significant. Conclusion: These data will be served as basic data for the evaluation of postoperative assessment of the patients with vocal polyp.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.1
• /
• pp.355-361
• /
• 2015

Background: Deletion types of genetic variants of glutathione S-transferase (GST) M1 and T1, the GSTM1 null and GSTT1 null which are risk factors for certain cancers, have been ubiquitously found in human populations but their worldwide distribution pattern is unclear. Materials and Methods: To perform a meta-analysis, a systematic search for the literature on GSTM1 and GSTT1 null genotypes was done to identify 63 reports for 81 human populations. Relationships between the GSTM1 and GSTT1 null genotype frequencies and the absolute latitude of 81 populations were tested by Spearman's rank correlation coefficient. Results: A significant positive correlation was detected between the GSTM1 null genotype frequency and the absolute latitude (r=0.28, p-value <0.05), whereas the GSTT1 null genotype frequency and absolute latitude showed a significant negative correlation (r= -0.41 p-value <0.01). There was no correlation between the frequencies of GSTM1 and GSTT1 null genotype in each population (r= -0.029, p-value=0.80). Conclusions: Latitudinal clines of the distribution of the GSTM1 and GSTT1 null genotypes may be attributed to the result of gene-environmental adaptation. No functional compensation between GSTM1 and GSTT1 was suggested by the lack of correlation between the null frequencies for GSTM1 and GSTT1.