• Restorative Dentistry and Endodontics
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• v.31 no.5
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• pp.371-377
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• 2006

The purposes of this study were to assess the accuracy of measurements in pre-enlarged canals with small instruments and to compare the accuracies, in enlarged canal, with small size instruments and instruments that match the actual canal diameter using Root ZX, Bingo1020, SmarPex, and e-Magic Finder. Ten extracted teeth were embedded in an alginate model made for testing apex locators. A size 10 file was placed into the root canal until the tip of the file reached the plane of the major diameter of the foramen under a dental operating microscope at the 25 x magnification. The measurement was done with digital caliper and defined as actual length. Electronic length measurement with a size 10 file in pre-enlarged canal was done by reading the index indicating Apex of each device to gain a definite value After completion of canal enlargement to a size 45 file, each difference between actual length and electric measurement value with a size 10 and 40 files in enlarged canal was recorded as L10 and L40. The one-way ANOVA and Scheffe's multiple range tests were computed for analyze the differences among the four apex locators in the same group. The Student's t-test between L10 and L40 of each locator was done. The accuracies of electronic measurements were significantly different among the 4 devices. The file size made no difference on the accuracy of electronic measurement in enlarged canal with same device. The e-Magic Finder was the most accurate device among the 4 apex locators used in this study.

• The Korean Journal of Applied Statistics
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• v.23 no.5
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• pp.883-890
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• 2010

Since Fisher's exact test is conducted conditional on the observed value of the margin, there are two kinds of the exact power, the conditional and the unconditional exact power. The conditional exact power is computed at a given value of the margin whereas the unconditional exact power is calculated by incorporating the uncertainty of the margin. Although the sample size is determined based on the unconditional exact power, the actual power which Fisher's exact test has is the conditional power after the experiment is finished. This paper investigates differences between the conditional and unconditional exact power Fisher's exact test. We conclude that such discrepancy is a disadvantage of Fisher's exact test.

• Fashion & Textile Research Journal
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• v.16 no.5
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• pp.766-775
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• 2014

This study is aimed to research the actual wearing condition of ballet dancewear of girls aged between 2 and 6 years on its design, size and fit. Survey data were collected from 171 mothers who have a girl learning ballet dance. The questionnaire was composed with ballet education, ballet dancewear purchasing, preference on design, size selection, and fitting. The collected data were analyzed with frequencies statistics, ${\chi}^2$-test, ANOVA using the SPSS WIN 20.0. The results are as follows; High rate of respondents said that the purpose of ballet education was for good body balance, leisure activity, and height growth. The main method of purchase was online shopping. The design, price, size and fit were identified as important ballet dancewear attributes for girls. The most preferred style of ballet dancewear were 'short sleeve skirted leotard' and 'camisole skirted leotard' which look like dress. The respondents reported slight satisfaction with size and fit, price, convenience in action, sewing and durability. The most preferred sizing system was code by height but any ballet dancewear makers don't use code by height. Therefore it is difficult for consumers to select size. Retailers and manufacturers could potentially use the results of this study to improve the sizing system and fit for children's ballet dancewear.

• Journal of Korean Dental Science
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• v.12 no.2
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• pp.58-65
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• 2019

Purpose: This study was aimed to investigate the possibility of utilizing smart device-based test (SBT) for competency evaluation in dental education and to analyze the student responses on overall competency evaluation using SBT method, in comparison to ubiquitous-based test (UBT). Materials and Methods: Questionnaire surveys have been conducted at Yonsei University College of Dentistry from 2015 to 2018 to obtain students' feedback on the application of SBT to competency evaluation. In addition, in order to supplement the competency evaluation procedure, considerations were explored by comparing the expected and actual difficulty of each item when preparing items for competency evaluation with SBT. Result: According to the survey results, student responses between the initial two years (2015 and 2016) differed from those in next two years (2017 and 2018). Students in 2017 and 2018 had more positive responses on competency evaluation with SBT. To determine the test validity, criterion-referenced evaluation was adopted to compare the data in 2017 and 2018 and slight differences in test difficulty in 2018 between the expected and actual difficulty of items were found. Conclusion: The results indicated that SBT was more appropriate for competency evaluation than UBT, based on four-year period of competency evaluation. The SBT was not affected by either the file size or the number of test-takers. Interestingly, students were not sensitive to test version of competency evaluation (paper-based test and SBT). This study suggests that the quality of the test items should be measured by continuous monitoring of the expected and actual difficulty of items for determining test validity. More detailed results and discussions of the findings are given for the development of test procedure and further potential research directions in dental education.

• Journal of the Korean Home Economics Association
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• v.40 no.8
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• pp.183-190
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• 2002

This study was aimed at investigating the satisfaction in relation to clothing design and size-fit for nurse uniform in Korea. The subjects were 986 female nurses working in 12 hospitals selected by convenience sampling. The data were collected by questionnaires. Using SPSS package, frequency, percentage, t-test, ANOVA and SNK test were conducted. The results were divided into 2 categories as fellows; 1) Results of the satisfaction with the size-fit and size system of the nurse uniforms : Nurses satisfied at the individual size-fit system than ready-made size system. There was a considerable difference of the satisfaction with the size-fit depending on age and clinical career. And more than half of nurses were needed the concrete and precise size system. 2) Results of the actual design condition and clothing satisfaction : Nurses wore two-piece pants suits more than classical designed one-piece style. The princess-line, convertible collar and yoke design were preferred for nurse uniform with the high satisfaction. 41.6 percent of respondents used the cap obligatory and the white color and a patterned textile were generally used. The used fabrics were only polyester and cotton/polyester mixed spinning.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.4
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• pp.253-259
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• 2018

Structure behaviors resulting from an earthquake are experimentally simulated mainly through a shaking table test. As for large-scale structures, however, size effects over a miniature may make it difficult to assess actual behaviors properly. To address this problem, research on the hybrid simulation is being conducted actively. This method is to implement numerical analysis on framework members that affect the general behavior of the structure dominantly through an actual scale experiment and on the rest parts by applying the substructuring technique. However, existing studies on hybrid simulation focus mainly on Slow experimental methods, which are disadvantageous in that it is unable to assess behaviors close to the actual level if material properties change depending on the speed or the influence of inertial force is significant. The present study aims to establish a Real-time hybrid simulation system capable of excitation based on the actual time history and to verify its performance and applicability. The hybrid simulation system built up in this study utilizes the ATS Compensator system, CR integrator, etc. in order to make the target displacement the same with the measured displacement on the basis of MATLAB/Simulink. The target structure was a 2-span bridge and an RC pier to support it was produced as an experimental model in order for the shaking table test and Slow and Real-time hybrid simulations. Behaviors that result from the earthquake of El Centro were examined, and the results were analyzed comparatively. In comparison with the results of the shaking table test, the Real-time hybrid simulation produced more similar maximum displacement and vibration behaviors than the Slow hybrid simulation. Hence, it is thought that the Real-time hybrid simulation proposed in this study can be utilized usefully in seismic capacity assessment of structural systems such as RC pier that are highly non-linear and time-dependent.

• Journal of the Korean Data and Information Science Society
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• v.9 no.2
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• pp.263-273
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• 1998

In this paper, we consider some approximate testings for the reliability of the stress-strength model when the stress X and strength Y each depends linearly on some explanatory variables z and w, respectively. We construct a bootstrap procedure for testing for various values of the reliability and compare the power of the bootstrap test with the test based on Mann-Whitney type estimator by Park et.al.(1996) for small and moderate sample size.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.04a
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• pp.515-520
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• 1997

This research is aimed at the development of the composite beam-column connection system by which the steel beam can be connected to the R/C column with smooth stress transfer. As the first step of the structural performance tests of the system, bearing resistance test has been carried out for actual size specimen. From the test, the connection system has been proved to take good bonding and stress transfer to the surrounding concrete with negligible relative displacements.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.182-183
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• 2014

In case of large soft body impact test at the construction site, the test conditions are different from conditions at the laboratory, and the length of rope to hold the impact specimen must be changed. In a previous study, the fact that the size of impact load is varied by the length of rope on the large soft body impact specimen was confirmed. In this study, the length of rope and fall height were set as independent variables to conduct the load analysis test. It was determined that the load fluctuation was occurred depending on the length of rope under the fall height over 100 mm, and it is concluded that the additional setup of fall height to modify the actual impact load size is required when the length of rope is below 2.5 m. In this study, the modified formula to put equal size of impact load regardless of the length of rope was extracted through the experiment.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.4
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• pp.231-238
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• 2019

A conventional lumped-mass stick model is based on the tributary area method to determine the masses lumped at each node and used in earthquake engineering due to its simplicity in the modeling of structures. However the natural frequencies of the conventional model are normally not identical to those of the actual structure. To solve this problem, recently an updated lumped-mass stick model is developed to provide the natural frequencies identical to actual structure. The present study is to investigate the seismic response accuracy of the updated lumped-mass stick model, comparing with the response results of the shaking table test. For the test, a small size four-story steel frame structure is prepared and tested on shaking table applying five earthquake ground motions. From the comparison with shaking table test results, the updated model shows an average error of 3.65% in the peak displacement response and 9.68% in the peak acceleration response. On the other hand, the conventional model shows an average error of 5.15% and 27.41% for each response.