• Proceedings of the Korean Association for Survey Research Conference
• /
• 2000.11a
• /
• pp.157-168
• /
• 2000

In this paper we point out another advantage of systematic sampling over simple random sampling, which have not yet been spelled out in the literature. After a single sample is drawn by a sampling scheme, it is important to check whether the achived sample represents the population well or not. Therefore, a sampling scheme which avoids the possibility of selecting non-preferred samples is desirable. The simulation results are given to illustrate that, in the ordered population, the possibility of selecting non-preferred sample by systematic sampling is lower than that by simple random sampling.

• Survey Research
• /
• v.2 no.2
• /
• pp.153-165
• /
• 2001

In this paper we point out another advantage of systematic sampling over simple random sampling, which have not yet been spelled out in the literature. After a single sample is drawn by a sampling scheme, it is important to check whether the achived sample represents the population well or not. Therefore. a sampling scheme which avoids the possibility of selecting non-preferred samples is desirable. The simulation results are given to illustrate that, in the ordered population, the possibility of selecting non-preferred sample by systematic sampling is lower than that by simple random sampling.

• Journal of Digital Convergence
• /
• v.19 no.1
• /
• pp.249-260
• /
• 2021

This study is a meta-analysis study conducted to integrate and analyze the results of flip-learning studies for Korean nursing students. We searched PubMed, EMBASE, Cochrane, CINAHL, and Korean databases. Randomized controlled trials (RCTs) and Non-Randomized controlled trials (Non-RCTs) evaluating the effects of flipped learning for Korean nursing students were included. Standardized mean differences (SMDs) with 95% confidence intervals (CIs) were calculated using a random-effects meta-analysis. The entire effect size in flipped learning was big in effect size (SMD = 1.21; 95% CI = 0.84 to 1.63; I2 = 93.9; n = 23) compared to the control groups. The analysis results of subgroups according to the classification of Bloom showed that flipped learning was found to have a significant effect on psychomotor domain, cognitive domain, and affective domain. A total of 10 literature analyses, this meta-analysis showed that flipped learning on Korean nursing students is effective in psychomotor, cognitive, and affective domain than the traditional teaching method. The flip learning can be integrated into theoretical and practical nursing education to improve the academic performance of nursing students.

• The Korean Journal of Applied Statistics
• /
• v.36 no.5
• /
• pp.381-397
• /
• 2023

The most representative design used in clinical trials is randomization, which is used to accurately estimate the treatment effect. However, comparison between the treatment group and the control group in an observational study without randomization is biased due to various unadjusted differences, such as characteristics between patients. Propensity score weighting is a widely used method to address these problems and to minimize bias by adjusting those confounding and assess treatment effects. Inverse probability weighting, the most popular method, assigns weights that are proportional to the inverse of the conditional probability of receiving a specific treatment assignment, given observed covariates. However, this method is often suffered by extreme propensity scores, resulting in biased estimates and excessive variance. Several alternative methods including trimming, overlap weights, and matching weights have been proposed to mitigate these issues. In this paper, we conduct a simulation study to compare performance of various propensity score weighting methods under diverse situation, such as limited overlap, misspecified propensity score, and treatment contrary to prediction. From the simulation results overlap weights and matching weights consistently outperform inverse probability weighting and trimming in terms of bias, root mean squared error and coverage probability.

• Korean Journal of Microbiology
• /
• v.41 no.2
• /
• pp.105-111
• /
• 2005

Streptomyces produces many kinds of secondary-metabolites including antibiotics. Screening of a new compound and elucidation of a biosynthetic pathway for the secondary metabolites are very important fields of biology, however, there is a main problem that most of the identified compounds are already researched compounds. To solve these problems, a microarray system that is based on the data related to the biosynthetic genes for secondary-metabolites was designed. For the main contents of DNA microarray, the important genes for the bio-synthesis of aminoglycosides, polyenes group, enediyne group, alpha-glucosidase inhibitors, glycopeptide group, and orthosomycin group were chosen. A DNA microarray with 69 genes that were involved in the bio-synthesis for the antibiotics mentioned above was prepared. The usability of the DNA microarray was confirmed with the chromosomal DNA and total RNA extracted from S. coelicolor whose genomic sequence had already been reported.

• Korean Journal of Applied Biomechanics
• /
• v.18 no.1
• /
• pp.31-38
• /
• 2008

The purpose of this study was to investigate the effects of anterior cruciate ligament (ACL) injury prevention program on the ground reaction force during the rebound in female highschool basketball players. Sixteen highschool female basketball players (ages 16 to 18 years) were participated in this study. Eight of these players participated in a 8-week ACL injury prevention program. Before and After ACL injury prevention program, initial peak value(%BW), maximum peak value(%BW), impulse(%BW sec), and loading rate(N/sec) were measured in the players. The experiment group after ACL injury prevention program showed significant decreased initial peak value, impulse, and loading rate.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.3
• /
• pp.1946-1956
• /
• 2015

The purpose of the this study was to provide objective evidence through a systematic review and meta-analysis regarding the effects of self-management in knee osteoarthritis. Articles published between 1999 and 2013 from periodicals indexed Ovid Medline, CINAHL, PubMed, RISS, KISS and other databases were selected, using the following key words: Osteoarthriti* OR OA, self-(management OR care OR help). A selection of 11 studies(7 randomized controlled trials and 4 quasi-experimental interventions that were used were exercise, education, massage and self-help group. As a result of mera-analysis, self-management significantly effected pain, physical function, activities of daily living, and self-efficacy. In particular, self-management showed great effect on ADL, and moderate effect on pain and physical function. Based upon these result, it is necessary to develop a standardized self-management program for knee osteoarthritis patients.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.7
• /
• pp.236-241
• /
• 2019

Lumbar stabilization exercise is a popular exercise method in recent clinicians, as it strengthens muscles around the spine and abdominal muscles, but there is a lack of research on the effects of pulmonary function and respiratory pressure. So, this study examined whether abdominal bracing exercise, a typical lumbar stabilization exercise, was effective in pulmonary function and respiratory pressure. In this study, a total of 20's 40 subjects were recruited and randomly divided into an abdominal bracing exercise group(n=20) and control group(n=20). Abdominal exercise group underwent 25 minutes of exercise. Pulmonary function and respiratory pressure values were measured to analyze respiratory function. As a results of the experimental group, there were significant improvements in FVC, FEV1, PEF and MEP(p<.05) and there was a significant difference in the comparison between groups, except the MIP. These results suggest that abdominal bracing exercise can be presented as effective exercises to improve respiratory function.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
• /
• v.9 no.3
• /
• pp.533-540
• /
• 2019

This study investigated the effect of extracorporeal shock wave therapy on nerve regeneration in nerve injured rats. In this study, we used 30 male Sprague-Dawley rats weighing 230-280g and 6 weeks old. Study groups were divided into two groups using a random sampling method: experimental group (n=15) treated with extracorporeal shock wave after sciatic nerve injury and control group (n=15) treated without extracorporeal shock wave after sciatic nerve injury. In this study, extracorporeal shock wave therapy equipment (OPTIMUS, SALUS TALENT 3, Korea) was used to apply extracorporeal shock wave therapy and applied to the sciatic nerve crush area of the right hind limb using low intensity. We measured the stance time and stride distance of the affected side using dartfish software. There was a statistically significant difference in the change of stance time and stride distance of the affected side between the experimental group using extracorporeal shock wave therapy and the control group without extracorporeal shock wave treatment. In conclusion, extracorporeal shock wave therapy has a positive effect on nerve regeneration.

• The Journal of the Korea Contents Association
• /
• v.10 no.5
• /
• pp.268-284
• /
• 2010

The purpose of this study was to evaluate the effects of horseback riding simulation training(HRST) on gross motor function of children with cerebral palsy. Twenty-four children with cerebral palsy participated were divided into two groups randomly. Control group and experimental group both received 30 minutes of regular neuro-rehab exercises for three times a week per twelve weeks, but experimental group received additional 15 minutes of the HRST. Gross Motor Function Measure(GMFM) was used to evaluate the changes before and after HRST. Normalized GMFM scores were compared using Mann-Whitney U test, statistical significance was set at a=.05. The results were as followings: First, in each compared before and after the experiment, the control group showed significantly increased GMFM score in dimensions A and B. The experimental group showed significant increasing in all dimensions of GMFM test. Second, the experimental group showed significant differences comparing to control group in dimensions C, D and E of GMFM test. Consequently, HRST should be considered as a therapeutic method for physical therapy for the children with cerebral palsy to improve the functional movements.