• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.44 no.1
• /
• pp.25-28
• /
• 2018

Objectives: This study aimed to describe recent patterns in the types of statistical test used in original articles that were published in Journal of the Korean Association of Oral and Maxillofacial Surgeons. Materials and Methods: Thirty-six original articles published in the Journal in 2015 and 2016 were ascertained. The type of statistical test was identified by one researcher. Descriptive statistics, such as frequency, rank, and proportion, were calculated. Graphical statistics, such as a histogram, were constructed to reveal the overall utilization pattern of statistical test types. Results: Twenty-two types of statistical test were used. Statistical test type was not reported in four original articles and classified as unclear in 5%. The four most frequently used statistical tests constituted 47% of the total tests and these were the chi-square test, Student's t-test, Fisher's exact test, and Mann-Whitney test in descending order. Regression models, such as the Cox proportional hazard model and multiple logistic regression to adjust for potential confounding variables, were used in only 6% of the studies. Normality tests, including the Kolmogorov-Smirnov test, Levene test, Shapiro-Wilk test, and $Scheff{\acute{e}}^{\prime}s$ test, were used diversely but in only 10% of the studies. Conclusion: A total of 22 statistical tests were identified, with four tests occupying almost half of the results. Adoption of a nonparametric test is recommended when the status of normality is vague. Adjustment for confounding variables should be pursued using a multiple regression model when the number of potential confounding variables is numerous.

• Aerospace Engineering and Technology
• /
• v.4 no.1
• /
• pp.39-44
• /
• 2005

To validate the rotor performance analysis, 3D Computational Fluid Dynamics(CFD) analysis was performed for tilt rotor aeroacoustic model(TRAM). Also, 3D vehicle with rotating rotors was simulated for rotor power effect analysis. Multiple reference frame(MRF) and sliding mesh techniques were implemented to capture the effect of rotor revolution. CFD results were compared with the wind tunnel test results to validate their accuracy. At helicopter mode, CFD analysis predicted lower thrust than the wind tunnel test but CFD results showed good agreement with the test result at cruise mode. Rotor power effect decreased the lift but did not change drag and pitching moment.

• Proceedings of the Korean Geotechical Society Conference
• /
• 1994.09a
• /
• pp.265-272
• /
• 1994

The relative density seems to be important as a factor of controlling the physical properties in the case of cohesionless soil ground as sand. Therefore, the study is more important about the method for reappearing the same relative density when the specimen of shearing test is to be produced or the model test of ground is to be made. In this study, the apparatus making use of the multiple sieving pluviation method - one of the reappearance of relative density - could be made. Using this apparatus, tests were practiced varying the factors such as the size of sieve mesh and the number of sieve, the amount of falling discharge, the falling height etc. about the standard sand in Jumunjin and Hadong sand. When laboratory test is performed by the cohensionless soil , it presents the method for reappearing of the relative density in field.

• ETRI Journal
• /
• v.30 no.3
• /
• pp.403-411
• /
• 2008

This paper introduces an interconnect delay fault test (IDFT) controller on boards and system-on-chips (SoCs) with IEEE 1149.1 and IEEE 1500 wrappers. By capturing the transition signals launched during one system clock, interconnect delay faults operated by different system clocks can be simultaneously tested with our technique. The proposed IDFT technique does not require any modification on boundary scan cells. Instead, a small number of logic gates needs to be plugged around the test access port controller. The IDFT controller is compatible with the IEEE 1149.1 and IEEE 1500 standards. The superiority of our approach is verified by implementation of the controller with benchmark SoCs with IEEE 1500 wrapped cores.

• Proceedings of the Korean Society for Quality Management Conference
• /
• 2007.04a
• /
• pp.444-448
• /
• 2007

The purpose of this research is to test the effects of employee perceived job characteristics on service quality. Empirical analysis was based on the data of 692 hotel employees from Seoul and Gyung-gi province. To test the relationship between job characteristics and service quality, multiple regression analysis was applied, and hierarchial regression analysis(Cohen & Cohen, 1983) applied to test the moderating effects of gender and tenure. Multiple regressional analysis showed that job importance, job variety, and feedback had an affirmative impact on tangibility, reliability, responsiveness, assurance, empathy, but autonomy had a negative impact on tangibility, reliability, responsiveness, assurance.

• Communications for Statistical Applications and Methods
• /
• v.3 no.3
• /
• pp.205-214
• /
• 1996

As flexible Bayesian test criteria for nested point null hypotheses of multiple regression coefficients, partial and overall Bayes factors are introduced under a class of intuitively meaningful prior. The criteria lead to a simple method for considering different prior beliefs on the subspaces that constitute a partition of the coefficient parameter space. A couple of tests are suggested based on the criteria. It is shown that they enable us to obtain pairwise comparisons of hypotheses of the partitioned subspaces. Through a Monte Carlo simulation, performance of the tests based on the criteria are compared with the usual Bayesian test (based on Bayes factor)in terms of their respective powers.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.28 no.9
• /
• pp.35-44
• /
• 2014

This study was to secure the safety of poor appearance distribution concrete poles effectively and to reduce the replacement costs of them by developing a soundness evaluation index. The researcher of this study investigated poor appearance types of concrete pole, collected 53 of test samples, and tested pole strength. As a result of strength test, only 17 percent of poor appearance concrete poles were below 2.0 of safety factor spec. As results of multiple regression analysis, it is verified that surface air void, horizontal crack, net-shaped crack, elapsed year, vertical crack, and deterioration in concrete compressive strength have statistically negative effects on safety factor of concrete poles in a significant level. The researcher set up a soundness evaluation index by using multiple regression equation, and suggested that poor appearance concrete poles should be replaced or reinforced only in case of soundness evaluation score of 150 or above.

• Journal of applied mathematics & informatics
• /
• v.26 no.3_4
• /
• pp.679-688
• /
• 2008

In multivariate regression analysis there exist many influence measures on the regression estimates. However it seems to be few of influence diagnostics on test statistics in hypothesis testing. Case-deletion approach is fundamental for investigating influence of observations on estimates or statistics. Tang and Fung (1997) derived single case-deletion of the Wilks' ratio, Lawley-Hotelling trace, Pillai's trace for testing a general linear hypothesis of the regression coefficients in multivariate regression. In this paper we derived more extended form of those measures to deal with joint influence among observations. A numerical example is given to illustrate the effect of joint influence on the test statistics.

• Journal of the Korean Home Economics Association
• /
• v.27 no.3
• /
• pp.71-78
• /
• 1989

As the level of life improves, the eating habit is changing from rice meal to bread meal and at the time, eat more strawberry jam than before. We tried to study to select the good cooking method and the proper strawberry variety for the jam through the sensory evaluation We made four kinds jam of Bogyo-Joseoung and Ai-berry by different cooking methods, the result6s of the sensory evaluation are as follow: The jam of Ai-berry is better than that of Bogyo-Joseoung by the paired comparison test but the difference between those, if we add some lemon to the jam of Bogyo-Joseoung and Ai-berry, is very little. The multiple comparison test proves the sourness, if added some lemon and citric acid, become better and the color and viscosity, if added pectin, became better. The overall preference about jam, if pectin and citric acid were added together, was best. In addition, we evaluated the quality of jammed bread by multiple comparison test. The result is like this: The jam with lemon is very good in color, flavor, sourness and texture, but the jam with pectin and citric acid was the best in overall preference.

• Korean Journal of Human Ecology
• /
• v.2 no.2
• /
• pp.49-62
• /
• 1999

The purpose of this study is to evaluate the combination of details on the maternity clothes of one-piece type through visual evaluation which helps compensating pregnant women＇s body defects for their more attractive fashion styles. The data evaluated by a multiple ranking test were analyzed by mean, paired t-test, general linear models procedure and Duncan＇s multiple ranged test. The result are as follows : 1) The pregnant woman wearing the one-piece dress with notched collar, pleats and whole button looks longer in lower part of bodies, smaller in upper body, slimmer, have less appeared bust and abdomen, more balanced as a Whole than when wearing others. And also, it makes a pregnant woman be seen more refined and simple. 2) In case of a pregnant woman, a one-piece dress with notched collar, tuck and whole button makes her look longer in neck, narrower in shoulder, and more active than when wearing others. 3) With roll collar, pleats and whole button, it looks taller and more graceful than when wearing others.