• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.1
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• pp.91-97
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• 2011

The purpose of this study was to evaluate RPM maintenance in X-Smart according to the power supplied by the AC adapter and rechargeable battery. Five new X-Smart were used in this study. A handpiece with rubber disk which has reflective tape was mounted on the vice. To measure the RPM, a non-contact type digital tachometer was used. RPM measurements were recorded every 5 minutes to 180 minutes and repeated 3 times per motor from each power source. To evaluate a difference of the RPM changes, two-way repeated measures were performed using $SPSS^{TM}$ 14.0. All tests were conducted at the 95 percent confidence level. There was no significant difference in the RPM change between the power sources. Continuous use of X-Smart with a rechargeable battery for up to 180 minutes could be safely used as an endodontic wireless motor with a reliable RPM maintenance.

• Information Systems Review
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• v.17 no.2
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• pp.101-132
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• 2015

National technical qualifications to enhance an individual's vocational skills, the competitiveness of companies and countries have an important function to improve. Especially 'qualifications' will have a signal function to show objectively measure an individual's ability with the 'Education' The "knowledge necessary for the performance of their duties. Technology will gain knowledge about such assessment or recognition is based on certain criteria and procedures." Learning to qualify are being made through a smart learning a lot. Due to the revolution of the Internet in recent years with the development of information and communication technologies are entering into a knowledge society, the importance of information and knowledge. This contemporary smart learning education system is continuing to rapidly growing in pace with the changing time and space constraints, without teaching and learning is taking place. The purpose of this study is the ARCS motivation theory can determine a representative theory of human motivation factors and basic psychological needs dealing with the human nature of the psychological needs Interactivity and immersive learning, and to validate the empirical causality Affecting the continued use of smart learning through fun. Specifically, attention, relevance, confidence in the ARCS motivation, see their effect on the learning flow through the satisfaction we analyze empirically. Through this national technical qualifications smart learner's learning by supporting the implicit synchronization of students in learning are the degree of continued use. Therefore, to achieve the objectives of national technical qualifications and skills through a smart learning can contribute to the activation of the development and certification of course industry.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.4
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• pp.427-434
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• 2016

The aim of this study was to compare the mechanical properties of high viscosity bulk-fill resin composites, $Filtek^{TM}$ Bulk Fill Posterior Restorative (FBF) and $Tetric^{(R)}$ N-Ceram Bulk Fill (TBF), with conventional composite ($Filtek^{TM}$ Z-350 XT, Z-350). The Vickers hardness test which indicates the degree of conversion was performed and the dye penetration test was performed to measure the microleakage which indicates polymerization shrinkage amount. To minimize experimental error, the standardized 3D-printed molds and the bovine teeth were used. Obtained data were analyzed by the Kruskal-Wallis test and Mann-Whitney test with the confidence interval of 95%. In the microhardness test within 1 hour of polymerization, lower surface of FBF and TBF showed significantly lower value than that of Z-350 (p < 0.05). But after 24 hours, the microhardness of FBF had increased and showed no significant difference with Z-350 (p > 0.05). In top and 2 mm depth surface, mean microhardness values were in the following order: Z-350 > FBF > TBF (p < 0.05). The mean microleakage value of TBF was significantly lower than others (p < 0.05). For clinical application of bulk-fill resin composites, caution for applying masticatory forces during 24 hours after polymerization is advised and further studies to decrease microleakage should be conducted.

• Journal of the Korean earth science society
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• v.32 no.2
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• pp.225-238
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• 2011

The purpose of this study was to explore the factors that are critical for successful scientific inquiry activity in the classroom and to analyze the students' abilities of 'Doing' scientific inquiry. Two hundred and forty gifted science students in grades $7^{th}$ and $8^{th}$ participated in this study and demonstrated their abilities of framing questions and designing investigation through a survey questionnaire. The survey was developed for measuring factors in terms of personal and interactive variables that are needed for 'Doing' a successful scientific. Additionally, two other questionnaires were developed to measure students' abilities of framing testable questions and designing the investigation in a sequence. The results were as follows: Students' learning motivation factors as personal variable (self-confidence about group and inquiry activity, views about inquiry value) also considered as influential for students' group inquiry activity. Other four components of interactive variable (grouping, kinds of task, physical context, and teachers' role) were found to be influential in successful students' 'Doing' group inquiry activity. In students' evaluation of group inquiry activity, the grouping factor was the most critical one for a successful 'Doing' inquiry activity. Participating students showed some level of inability of in the process of framing inquiry question and designing investigation.

• Tuberculosis and Respiratory Diseases
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• v.80 no.1
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• pp.35-44
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• 2017

Background: Isolation of M. tuberculosis (MTB) is required in cases of Tuberculous pleural effusion (TBPE) for confirming diagnosis and successful therapy based on drug sensitivity test. Several studies have focused on predictors of MTB culture positivity in TBPE. However, the clinical role of loculated TBPE as a predictor of MTB cultivation from TBPE remains unclear. The aim of this study was to examine possible predictors including loculation of TBPE of MTB culture positivity in TBPE. Methods: We retrospectively examined associations between clinical, radiological, microbiological, and laboratory characteristics and positive MTB culture from TBPE to determine a potent predictor of culture positivity. Results: From January 2011 to August 2015, 232 patients with TBPE were identified. Of these, 219 were finally analyzed. Among them, 69 (31.5%) were culture positive for MTB in TBPE and 86 (39.3%) had loculated TBPE. In multivariate logistic regression analysis, the loculation of TBPE was independently associated with culture positivity for MTB in TBPE (adjusted odds ratio [OR], 40.062; 95% confidence interval [CI], 9.355-171.556; p<0.001). In contrast, the lymphocyte percentage of TBPE (adjusted OR, 0.934; 95% CI, 0.899-0.971; p=0.001) was inversely associated with culture positivity for MTB in TBPE. Conclusion: In clinical practice, identification of loculation in TBPE is easy, reliable to measure, not uncommon and may be helpful to predict the possibility of positive mycobacterial culture.

• Fire Science and Engineering
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• v.32 no.2
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• pp.57-66
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• 2018

The most urgent requirement in the event of disaster and fire in a skyscraper is to establish a system that enables people inside to evacuate safely. Hence, a practical direction needs to give evacuees confidence in the evacuation by reducing the psychological anxiety caused by the relatively large number of people inside and at the same time, the physically prolonged evacuation travel line. Evacuation tests with large numbers of people were conducted three times to solve these challenges and identify phenomena and issues that occurred during the experiment. The results revealed the factors that could cause a delay in evacuation and suggested improvements. The study results of this paper are as follows. First, a recent fire at a multipurpose high-rise resulted in a number of casualties due to a lack of experience with the disaster prevention system. To prevent such cases from occurring in advance, adaptability was achieved by conducting evacuation tests. Second, the data collected in the evacuation simulation statistics and the actual escape drills were compared and analyzed. Third, in the evacuation experiment, a large number of people could not participate in the experiment. The reasons for not participating were analyzed and their impact on the actual evacuation time was confirmed. Fourth, equipment aids were purchased to establish the optimal response measure to the causes of a delay in escape time and the standards for ensuring the safety of the evacuee were specified by developing improvements to minimize the evacuation delay time through comparative before and after analysis of the experiment. These results can be used for fire safety control of skyscrapers to improve the efficiency of evacuation.

• Journal of Preventive Medicine and Public Health
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• v.32 no.4
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• pp.505-512
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• 1999

Objectives : The purpose of this study was to assess the relationship between job strains and absenteeism from work. Methods : The study design was cross-sectional, and the study subjects consisted of 1,166 workers who were employed in the small-sized industries. A self administered questionnaire was used to measure the general characteristics, job characteristics(job demand, job control), and social support(coworker support, supervisor support) at work. The Job Content Questionnaire(JCQ) was used to assess job demand(2 items) and decision lattitude(10 items). Social support at work (10 items) was measured using JCQ. Sick absence was collected using self-report and were rechecked by the attendance record of their company. Odds ratios and 95% confidence intervals for the association between job strain and sick absence were estimated. The modifying effect of social support was evaluated by stratification. Logistic regression was used to estimate the relationship between job strain and sick absence. Results : In the bivariate analysis, the variables related to sick absence were age, marital status, occupation, job demand. Four distinctly different kinds of level of job strain were generated by the combination of job demand and job control: low strain group, high strain group, active group, and passive group. The crude odds ratio of high job strain was 1.78(95% CI: 1.26-2.53), and those of active group and passive group were 1.33(95% CI: 1.07-1.66) and 1.13 (95% CI: 0.88-1.47), respectively. The odds ratio of high job strain after adjusting for age and occupation were still significant The odds ratio of high job strain in low social support was 5.96(95% CI: 2.45-14.51), but that in high social support was 0.73(95% CI: 0.26-2.01). Conclusions : Job strain was associated with increased risk of absenteeism from work, and social support at work modified the association between job strain and sick absence.

• Journal of radiological science and technology
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• v.40 no.2
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• pp.197-203
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• 2017

The purpose of this study was to measure signal to noise ratio (SNR) according to change of equalization from region of interest (ROI) of heart shadow in chest image. We examined images of chest image of 87 patients in a University-affiliated hospital, Seoul, Korea. Chest images of each patient were calculated by using ImageJ. We have analysis socio-demographical variables, SNR according to images, 95% confidence according to SNR of difference in a mean of SNR. Differences of SNR among change of equalization were tested by SPSS Statistics21 ANOVA test for there was statistical significance 95%(p < 0.05). In SNR results, with the quality of distributions in the order of original chest image, original chest image heart shadow and equalization chest image, equalization chest image heart shadow(p < 0.001). In conclusion, this study would be that quantitative evaluation of heart shadow on chest image can be used as an adjunct to the histogram equalization chest image.

• 대한공업교육학회지
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• v.35 no.2
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• pp.1-24
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• 2010

The purpose of this study is to investigate provedly the effectiveness of the practice for the arts and crafts by machine for project based learning upon improving industrial high school students' key competency for vocation, and to provide the incumbent teachers and future teachers who want to conduct research, a similar study with the basic reference materials. The vocational key competencies interested in this study are communication ability, information usage skills, team work skills, problem solving skills, tool usage skills, and responsibility and confidence areas. Because the result of pre and post testing over these six areas has insignificant differences statistically, we reach a conclusion which project based learning is more effective than traditional practice methods at improving the vocational key competencies of industrial students. On the basis of the results of this study, I would like to suggest some kinds of things needed to improve the vocational key competencies of industrial high school students. First, we require the diverse research to investigate the best teaching and learning methods to cultivate people of ability with the vocational key competencies Second, it is required that to measure the extent of the improvement of the vocational key competencies of industrial high school students, we have to develop a more objective test tool than that used in this study. Third, in the light of facts that project based learning influences on improving the vocational key competencies of the industrial high school student, we will have to make an effort actively to find the best teaching and learning methods, like project based learning. Therefore, we need to give diverse training opportunities and financial support so that teachers can conduct research to find the best teaching and learning method at improving the vocational key competencies for industrial high school students.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.149-159
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• 1998

The reasonable prediction of time-dependent deformation of prestressed concrete(PSC) box girder bridges is very important for accurate construction as well as good serviceability. The long-term behavior is mostly influenced by the probabilistic characteristic of creep and shrinkage. This paper presents a method of statistical analysis and sensitivity analysis of creep and shrinkage effects in PSC box been taken into account - model uncertainty, parameter variation and environmental condition. The statistical and sensitivity analyses are performed by using the numerical simulation of Latin Hypercube sampling. For each sample, the time-dependent structural analysis is performed to produce response data, which are then statistically analyzed. The probabilistic prediction of the confidence limits on long-term effects of creep and shrinkage is then expressed. Three measure are examined to quantify the sensitivity of the outputs of each of the input variables. These are rank correlation coefficient(RCC), partical rank correlation coefficient(PRCC) and standardiozed rank regression coefficient(SRRC) computed on the ranks of the observations. Three creep and shrinkage models - i. e., ACI model. CEB-FIP model and the model in Korea Highway Bridge Specification - are studied. The creep model uncertainy factor and the relative humidity appear to be the most dominant factors with regard to the model output uncertainty.