• Genomics & Informatics
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• v.18 no.4
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• pp.45.1-45.5
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• 2020

With the ongoing rise of coronavirus disease 2019 (COVID-19) pandemic across the globe, interests in COVID-19 antibody testing, also known as a serology test has grown, as a way to measure how far the infection has spread in the population and to identify individuals who may be immune. Recently, many countries reported their population based antibody titer study results. South Korea recently reported their third antibody formation rate, where it divided the study between the general population and the young male youths in their early twenties. As previously stated, these simple point estimates may be misinterpreted without proper estimation of standard error and confidence intervals. In this article, we provide an updated 95% confidence intervals for COVID-19 antibody formation rate for the Korean population using asymptotic, exact and Bayesian statistical estimation methods. As before, we found that the Wald method gives the narrowest interval among all asymptotic methods whereas mid p-value gives the narrowest among all exact methods and Jeffrey's method gives the narrowest from Bayesian method. The most conservative 95% confidence interval estimation shows that as of 00:00 November 23, 2020, at least 69,524 people were infected but not confirmed. It also shows that more positive cases were found among the young male in their twenties (0.22%), three times that of the general public (0.051%). This thereby calls for the quarantine authorities' need to strengthen quarantine managements for the early twenties in order to find the hidden infected people in the population.

• Safety and Health at Work
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• v.13 no.4
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• pp.482-486
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• 2022

Background: This study aimed to estimate the annual prevalence and incidence of urolithiasis stratified by work status based on a large nationwide sample. Methods: This study used data from the National Health Insurance Service-National Sample Cohort from 2002 to 2015. The prevalence and incidence of urolithiasis were estimated based on work status and gender stratification. The risk of urolithiasis among workers was calculated using age-standardized incidence ratio with stratification of work type. Results: The prevalence of urolithiasis was significantly higher in workers than in non-workers, especially men, during the follow-up period. The total estimated number of urolithiasis cases was 41,086 and the overall incidence of urolithiasis was 0.3%. The age-standardized incidence ratio of urolithiasis was significantly higher among the total workers (1.14; 95% confidence interval, 1.13-1.16), self-employed workers (1.08; 95% confidence interval, 1.06-1.11), and paid workers (1.19; 95% confidence interval, 1.17-1.21) than among the non-working population. Conclusions: Workers, especially paid workers and men, were vulnerable to urolithiasis. Further studies are required to investigate the effects of working conditions on urolithiasis.

• International Journal of Reliability and Applications
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• v.7 no.2
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• pp.177-186
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• 2006

Typical confidence intervals for a mean or mean residual life (MRL) are centered about the mean or mean residual life. We discuss novel confidence intervals that produce statements like "we are 95% confident that the MRL function, e(t), is greater than a prespecified $\mu_o$ for all t in the interval [0, $\hat{\theta})$)" where $\hat{\theta}$ is determined from the sample data, confidence level, and $\mu_o$. Also, we can have statements like 'we are 95% confident that the MRL of population 1, namely $e_1$(t), is greater than the MRL of population 2, $e_2$(t), for all t in the interval [0, $\hat{\theta}$)" where $\hat{\theta}$ is determined from the sample data and confidence level. We illustrate these one and two sample confidence intervals on internal bonds (tensile strengths) for an important modem engineered wood product, called medium density fiberboard (MDF), used internationally.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.3
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• pp.59-65
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• 2009

To investigate a posttraumatic stress, social support and work burden and to identify high risk group and related factors which were exerted influence on posttraumatic stress of firefighters. Data were gathered from total 264 firefighters consisting of 85 fire distinguishers & rescue workers, 96 emergency medical personnel and 83 in ambulance & fire truck drivers in C province and were analyzed 22 items by IES-R, 20 work burden items by Choi(2000), 8 social support items by Oh(2006) using SPSSWIN 14.0 program. Posttraumatic stress of general characteristics by work was showed significant difference in age, marriage status, education, position, office duration, mobilization frequency and experience of traumatic events. Posttraumatic stress were showed significant difference in 3 groups and fire distinguishers & rescue workers is the highest group. Posttraumatic stress was correlated with work burden(r=.317, p<0.01) for fire distinguishers & rescue workers, social support(r=-.331, p<0.01) and work burden(r=.522 p<0.001) for emergency medical personnel and work burden(r=.454, p<0.01) for ambulance & fire truck drivers. The high risk groups are fire distinguishers & rescue workers(60%), emergency medical personnel(55.2%)and ambulance & fire truck drivers(45.8%). Related factors are the experience seeing victim's danger for fire distinguishers & rescue workers(odds ratio=1.216, 95% confidence interval:1.068-1.383), and are work burden(odds ratio=1.100, 95% confidence interval:1.043-1.159) and office duration(odds ratio=1.010, 95% confidence interval 1.001-1.018) for emergency medical personnel, and are the experience seeing victim's danger(odds ratio=1.178, 95% confidence interval:1.010-1.373), age(odds ratio=1.129, 95%confidence interval:1.020-1.249), work burden(odds ratio=1.103, 95% confidence interval:1.034-1.177) for ambulance & fire truck drivers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.148-156
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• 2019

This study identified the effects of Depression, Anxiety, and Quality of Sleep on Excessive Daytime Sleepiness (EDS) in nursing students. Totally, 213 students of a nursing college located in C do, Korea, were enrolled for the study, which was accomplished through a questionnaire. Data were collected from May 20 to 30, 2019. The collected data were compiled using the SPSS/WIN 25.0 statistic program by applying Chi-square test, Paired t-test, Pearson's Coefficient, and Multiple logistic regression. The following results were obtained. The mean score for EDS was 8.95(±4.56), and Prevalence of EDS was determined to be 40.8%. The mean scores obtained for the affecting factors were Depression 10.05(±7.85), STAI-S 46.09(±9.50), STAI-T 46.47(±9.93), and Quality of Sleep 6.51(±2.95). Depression, STAI-S, STAI-T, and Quality of Sleep were significantly different for EDS and Non-EDS students (t=1.955, p=0.024; t=5.446, p<0.001; t=1.716, p=0.007; t=12.168, p<0.001; respectively). Multiple logistic regression revealed that factors associated with EDS were STAI-S and Quality of Sleep (adjusted odds ratio=1.04, 95% Confidence Interval=1.01-1.08; adjusted odds ratio=1.16, 95% Confidence Interval=1.04-1.29; respectively). These findings indicate the necessity to improve the quality of sleep and manage anxiety alleviation of nursing students, to reduce excessive daytime sleepiness.

• Therapeutic Science for Rehabilitation
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• v.9 no.4
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• pp.107-120
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• 2020

Objective : The purpose of this study was to investigate the effectiveness and basis of rehabilitation intervention in patients with spinal cord injury by systematic review and meta-analysis of randomized controlled studies. Methods : Two researchers independently searched and selected a study published in an academic journal using a search term in an international thesis database. A total of 21 studies met the selection criteria, and qualitative evaluation of the study was conducted using the PEDro Scale. Meta-analysis was performed using Comprehensive Meta-Analysis 3.0 program. Results : A total of 713 subjects were included. The results of the meta-analysis showed a score of 0.406 (95.0% confidence interval: 0.221 ~ 0.591) for intervention using physical activity and 0.505 (95.0% confidence interval: 0.449 ~ 1.528) for electronic stimulation therapy, which showed medium effect; educational intervention had a 0.248 (95.0% confidence interval: 0.033 ~ 0.464), and mixed intervention 0.280 (95.0% confidence interval: 0.122 ~ 0.438). It was shown that the effect of small (small). There was a significant heterogeneity in the statistical heterogeneity test, and thus the random effects model was selected and analyzed. Conclusion : The results showed that rehabilitation interventions were effective for patients with spinal cord injury. During the rehabilitation of spinal cord injury patients, clinicians are expected to contribute to the development of programs to improve their lifestyles.

• Communications for Statistical Applications and Methods
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• v.27 no.1
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• pp.47-64
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• 2020

In this paper, we derive some estimators of the scale parameter of the exponentiated half-logistic distribution based on the multiply Type-I hybrid censoring scheme. We assume that the shape parameter λ is known. We obtain the maximum likelihood estimator of the scale parameter σ. The scale parameter is estimated by approximating the given likelihood function using two different Taylor series expansions since the likelihood equation is not explicitly solved. We also obtain Bayes estimators using prior distribution. To obtain the Bayes estimators, we use the squared error loss function and general entropy loss function (shape parameter q = -0.5, 1.0). We also derive interval estimation such as the asymptotic confidence interval, the credible interval, and the highest posterior density interval. Finally, we compare the proposed estimators in the sense of the mean squared error through Monte Carlo simulation. The average length of 95% intervals and the corresponding coverage probability are also obtained.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.13 no.1
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• pp.19-35
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• 2009

Objectives : In the study on the waveform analysis of radial artery pulse diagnosis, we need to establish fundamentals of contemporary pulse diagnosis research. To achieve certain experimental basis on traditional pulse diagnosis, we have to research the differences of pulse waveform according to pressure (in 5 level) and position (Chon, Gwan, Cheok in radial artery). As a first step, in present thesis, we tried to find the differences of pulse waveform according to pressure. Methods and Results : In this research, we analyzed seven parameters of the waveform at five levels of pressure. The parameters are E(so called 'energy', a representative of pulse strength), h1(height of percussion wave) and h2(height of subincisura). The results were as follows. 1. When we analyzed the change of the waveform according to pressure in the left Gwan, E, hl, h2 and A differed between 1st and 2nd grade, between 1st and 3rd grade, between 1st and 4th grade, between 1st and 5th grade, between 2nd and 3rd grade, between 2nd and 5th grade, between 3rd and 5th grade and between 4th and 5th grade in 95% confidence interval. 2. And t2, t4 differed between 1st and 2nd grade, between 1st and 5th grade, between 2nd and 4th grade, between 2nd and 4th grade, between 2nd and 5th grade, between 3rd and 4th grade, between 3rd and 5th grade and between 4th and 5th grade in 95% confidence interval. 3. W differed between 1st and 3rd grade, between 1st and 4th grade, between 2nd and 3rd grade, between 2nd and 4th grade, between 2nd and 5th grade, between 3rd and 4th grade, between 3rd and 5th grade, and between 4th and 5th grade in 95% confidence interval. 4. And h2/h1 differed between 1st and 4th grade, between 1st and 5th grade, between 2nd and 4th grade, between 2nd and 5th grade, between 3rd and 4th grade & between 3rd and 5th grade in 95% confidence interval. 5. There were differences between 1st and 2nd grade & between 2nd and 5th grade in the case of t4/t2 in 95% confidence interval. And there were differences between 1st and 5th grade, between 3rd and 4th grade, between 3rd and 5th grade & between 4th and 5th grade in the case of W/A in 95% confidence interval. And were differences between 1st and 2nd grade, between 2nd and 3rd grade, between 2nd and 4th grade, between 3rd and 4th grade, between 3rd and 5th grade & between 4th and 5th grade in the case of A/E in 95% confidence interval. Conclusions : As mentioned above, we conclude that the waveform analysis according to five grade pressure in the left Gwan shows the difference of waveform in each grade pressure.

• The Korean Journal of Applied Statistics
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• v.27 no.4
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• pp.645-653
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• 2014

P-value is the probability of observing a current sample and possibly other samples departing equally or more extremely from the null hypothesis toward postulated alternative hypothesis. When p-value is less than a certain level called ${\alpha}$(= 0:05), researchers claim that the alternative hypothesis is supported empirically. Unfortunately, some findings discovered in that way are not reproducible, partly because the p-value itself is a statistic vulnerable to random variation. Boos and Stefanski (2011) suggests calculating the upper limit of p-value in hypothesis testing, using a bootstrap predictive distribution. To determine the sample size of a replication study, this study proposes thought experiments by simulating boosted bootstrap samples of different sizes from given observations. The method is illustrated for the cases of two-group comparison and multiple linear regression. This study also addresses the reproducibility of the points in the given 95% confidence interval. Numerical examples show that the center point is covered by 95% confidence intervals generated from bootstrap resamples. However, end points are covered with a 50% chance. Hence this study draws the graph of the reproducibility rate for each parameter in the confidence interval.

• International Journal of Highway Engineering
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• v.16 no.1
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• pp.41-48
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• 2014

PURPOSES : The lane width of the domestic highway is 3.5 ~ 3.6m and it has been designed nationwide. However, the distribution of the average vehicle widths, rearview mirror widths and lateral wheel paths by region appear different. Then, lane spare widths may differ by region followingly. Thus, the flexible design of freeway lane widths is required. METHODS : The methodologies of this paper are as follows. First, vehicle widths rearview mirror widths lateral wheel paths of vehicles driven four national expressways were measured. Second, lane spare widths by vehicle widths were calculated. Third, lane spare widths reflecting rearview mirror widths were calculated by using interval estimation. Additionally, lane spare widths reflecting vehicles lateral wheel paths were calculated. RESULTS : The results of this paper are as follows. First, lane spare widths by vehicle widths ranges 0.83 to 0.95m. Second, lane spare widths reflecting rearview mirror widths ranges 0.518 to 0.747m at the confidence interval 95%. Third, lane spare widths reflecting vehicles' lateral wheel paths ranges -0.022 to 0.322m at the curved sections and the confidence interval 95%. CONCLUSIONS : It may be concluded that the present lane spare widths are relatively narrow at the curved section. Thus, there is a need to consider expanded lane widths at the curved sections. Additionally, there is a need to consider flexible design of lane widths by various conditions.