• Journal of the Institute of Electronics Engineers of Korea TC
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• v.38 no.5
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• pp.1-8
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• 2001

This paper presents the analysis of fiber radio system transmitting OFDM signal. We propose a baseband equivalent system model and prove the relation between the IMD(intermodulation distortion) power and the number of subcarrier in the OFDM signal. Using this relation, we derive the CNH of the overall system. In terms of the required CNR for each digital modulation scheme, we extract the maximum number of the subcarrier in the OFDM signal using simulation and examine how the system parameters are related with the CNR.

• Communications for Statistical Applications and Methods
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• v.17 no.6
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• pp.767-777
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• 2010

This paper investigates the relationship between the passenger car demand and business activities in the OECD. The positively linear relationships changed suddenly since 1990 and the reason was thought to be the polarized economic development of USA and Japan. The cases of other countries supports this conclusion. According to the conclusion, we modeled and estimated the car demand function of Korea.

• Childhood Kidney Diseases
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• v.12 no.2
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• pp.150-156
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• 2008

Purpose : Many results have reported a correlation between the spot urine protein/creatinine ratio(P/C ratio) and 24-hour urinary protein(24UP) amount. This study was designed to evaluated correlation between 24UP amounts and P/C ratio in children and to find the factors that affect this correlation. Methods : 210 patients who visited the Department of Pediatrics in Busan Paik Hospital from september 2003 to december 2007 were included in this study. All the patients were divided into I, II, III/A, B, C group[I:24UP(mg/$m^2$/day)]<100, II: 100$\leq$24UP<1,000, III: 24UP$\geq$1,000, A: Cr excretion(mg/kg)<15, B: 15$\leq$Cr excretion<25, C: Cr excretion$\geq$25)]. Pearson correlation analysis was performed between 24UP and P/C ratio to evaluate the relationship. We defined fractional difference between 24UP and P/C ratio, and then performed multiple regression analysis. Results : There was a strong positive linear correlation between 24UP and P/C ratio in all patients, and the correlation was also good in each group. The factors affecting accurate quantitation of proteinuria using spot urine P/C ratio was creatinine excretion. Conclusion : Spot urine P/C ratio is a useful test to predict proteinuria roughly. Therefore, we expect that urine P/C ratio can be used as parameter instead of 24UP, if we set cutoff value of P/C ratio considered to creatinine excretion according to age and sex in large pediatric population.

• Environmental and Resource Economics Review
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• v.29 no.2
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• pp.145-170
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• 2020

This study analyzes the dependence structure between energy (crude oil, natural gas, coal) prices and economic (real and financial) uncertainty. Summary of the results of the dependence structure between energy prices and economic uncertainty analysis is as follows. First, the results of model selection show that the BB7 copula model for the pair of crude oil price and economic uncertainty, the Joe copula model for the pair of natural gas price and economic uncertainty, and the Clayton copula model for the pair of coal price and economic uncertainty were chosen. Second, looking at the dependency structure, it showed that the pair of energy (crude oil, natural gas, coal) prices and real market uncertainty show positive dependence. Whereas, the only pair of financial market uncertainty-crude oil price shows positive dependency. In particular, crude oil price was found to have the greatest dependence on economic uncertainty. Third, looking at the results of tail dependency, the pair of real market uncertainty-crude oil price and pair of real market uncertainty-natural gas price have an asymmetric relationship with the upper tail dependency. It can be seen that the only pair of financial market uncertainty-crude oil represents asymmetric relationships with the upper tail dependencies. In other words, combinations with asymmetric relationships have shown strong dependence when negative extreme events occur. On the other hand, tail dependence between economic uncertainty and coal price be not found.

• Journal of the Korea Society of Computer and Information
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• v.28 no.2
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• pp.171-179
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• 2023

This study was conducted to evaluate the association between knowledge of Coronavirus disease 2019 (COVID-19), perception of infection control and practice of infection control among dental hygienists. The questionnaires consisted of 9 demographic questions, 10 questions about COVID-19 knowledge, and 36 questions about perception and practice of infection control. The study analyzed 120 participants' data gathered from May 1 to May 31, 2021. For data analysis, T-test, ANOVA, and Pearson correlation were used. As a result, COVID-19 knowledge was 6.59 out of 10, the perception of infection control was 3.57 out of 4 and the practice of infection control was 3.55 out of 4. The COVID-19 knowledge(r=0.485) and perception of infection control(r=0.614) were significantly positively related to practice of infection control. To improve the practice of infection control in the dental field, education of infection control should be mandatory for dental hygienists. Also, the practice of infection control following "Dental Infection Control Standard Policy & Procedure" must be mandatory.

• Journal of the Korea Convergence Society
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• v.6 no.1
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• pp.71-76
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• 2015

Using a sample of publicly-traded Chinese firms, this study examines a relationship between managerial ownership and corporate debt maturity decisions. China has transformed dramatically into a market capitalist economy over the past decades. However, so far, little attention has been paid to the role of professional managers. In this situation, this study explores the effect of stock grants to managers as incentive system by providing evidence that managerial ownership affects corporate debt maturity decisions. The findings are as follows: First, I find that like US firms, managerial ownership is negatively related to the proportion of long-term debt. Second, I divide the entire sample into two subsamples of state-owned and privately owned firms. For the privately owned firms, I find that there is a negative relationship between managerial ownership and the proportion of long-term debt. In contrast, for the state-owned firms, the relationship is positive and insignificant.

• Clinical and Experimental Pediatrics
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• v.50 no.6
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• pp.549-555
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• 2007

Purpose : Pulse wave velocity (PWV) and ankle brachial index (ABI) are simple, non-invasive methods to assess arterial stiffness. These parameters are also known to be closely related to cardiovascular risk factors and diseases. The purposes of this study were to measure blood pressure, PWV, ABI in healthy Korean adolescents, set up their normal values and assess their correlations. Methods : Three hundred ninety two healthy adolescents (213 boys and 179 girls) underwent measurement of brachial ankle pulse wave velocity (baPWV), ABI, body mass index(BMI) and blood pressure from four extremities. Linear regression analysis was performed to reveal the correlations between PWV, ABI and independent variables. Results : Blood pressure and PWV were significantly higher in all extremities in males compared to females. Blood pressure of both brachial and ankle showed positive correlation with body weight, height, and BMI, whereas ABI showed no correlation with any of these indices. Conclusion : Blood pressure increases as body weight, height and BMI increases. PWV shows positive correlation with blood pressure. It will be helpful to predict the risks of cardiovascular diseases in adolescents.

• Journal of Industrial Convergence
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• v.22 no.4
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• pp.49-55
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• 2024

This study is a descriptive research study to determine the mediating effect of anxiety in the relationship between patient care communication and patient satisfaction among hospitalized patients. Data was collected using self-administered questionnaires from October to December 2021. The collected data were analyzed using descriptive statistics, Pearson's correlation coefficient, and hierarchical multiple regression using the SPSS 24.0 program, and the effectiveness of the mediation effect was tested using the Sobel test. As a result of the study, there was a positive correlation between patient care communication and patient satisfaction, and a negative correlation between patient care communication and anxiety. And there was also a negative correlation between patient satisfaction and anxiety. In the relationship between patient care communication and patient satisfaction, anxiety had a partial mediating effect (z=2.93, p<.001), with an explanatory power of 38.4%. In order to improve patient satisfaction based on the results of this study, it is necessary to develop a program that can improve nurses' patient care communication capabilities and reduce patients' anxiety.

• Korean Journal of Remote Sensing
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• v.33 no.2
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• pp.249-255
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• 2017

Antarctica isimportant area in order to understand climate change. In addition, this area is complex region where indicate warming and cooling trend according to previous studies. Therefore, it is necessary to understand the long-term variability of Antarctic energy budget. Net radiation, one of energy budget factor, is affected by albedo, and albedo cause negative radiative forcing. It is necessary to analyze a relationship between albedo and net radiation in order to analyze relationship between two factors in Antarctic climate changes and ice-albedo feedback. In thisstudy, we calculated net radiation using satellite data and performed an analysis of long-term variability of net radiation over Antarctica. In addition we analyzed correlation between albedo. As a results, net radiation indicates a negative value in land and positive value in ocean during study periods. As an annual changes, oceanic trend indicates an opposed to albedo. Time series pattern of net radiation is symmetrical with albedo. Correlation between the two factors indicate a negative correlation of -0.73 in the land and -0.32 in the ocean.

• Journal of Korea Entertainment Industry Association
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• v.14 no.8
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• pp.477-485
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• 2020

The purpose of this study was to verify the moderating effect of school life satisfaction in the relationship between cyberbullying victimization and suicidal ideation of adolescents. In this study, 1244 middle and high school students' data from the 2017 Children's and Youth Human Rights Survey conducted by the Korea Youth Policy Institute were used. The researcher used frequency analysis, independent sample T-test, one-way analysis of variance, correlation analysis and regression analysis using IBM SPSS statistics 20.0 for Windows. Results of the study are as follows: First, the cyberbullying victimization experience was higher in boys than girls, and suicidal ideation were more likely in girls than boys. Second, the cyberbullying victimization and school life satisfaction had a weak negative correlation, school life satisfaction and suicidal ideation had a negative correlation. And suicidal ideation had a weak positive correlation. Third, this study found that school life satisfaction have a moderating effect in the relationship between cyberbullying victimization and suicidal ideation. Based on the results of the study, the implications of suicide prevention programs for adolescents who have experienced cyberbullying victims and plans to activate them were proposed. This study is hoped to be used as a basis for the prevention of suicide in adolescents.