• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.9
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• pp.331-337
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• 2020

study analyzed the relationship between ChildCare Teachers' Office Stress on Happiness with Teacher Effectiveness. A survey was conducted on 243 childcare teachers in J area. The collected data was analyzed using the JAMOVI program to analyze the mediated effects and technical statistics. Results found that office stress, teacher efficacy, and sense of happiness of childcare teachers were found to meet the normality assumption. Second, the analysis of the relationship between office stress, teacher efficacy, and happiness showed a statistically significant negative correlation between administrative stress and teacher efficacy and happiness and teacher efficacy showed a significant positive correlation. Higher office stress led to less teacher effectiveness and happiness, and higher happiness led to higher teacher effectiveness. Third, office stress is a significant predictor of happiness and teacher's efficacy. In conclusion, office stress should be considered important in terms of happiness and teacher effectiveness and the direction of improvement in the treatment of child care teachers was suggested.

• The Korean Journal of Applied Statistics
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• v.16 no.1
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• pp.101-115
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• 2003

Lately there has been much theoretical and applied interest in linear models with non-normal heavy tailed error distributions. Starting Zellner(1976)'s study, many authors have explored the consequences of non-normality and heavy-tailed error distributions. We consider hierarchical models including selection models under a skewed heavy-tailed e..o. distribution proposed originally by Chen, Dey and Shao(1999) and Branco and Dey(2001) with Dirichlet process prior(Ferguson, 1973) in order to use a meta-analysis. A general calss of skewed elliptical distribution is reviewed and developed. Also, we consider the detail computational scheme under skew normal and skew t distribution using MCMC method. Finally, we introduce one example from Johnson(1993)'s real data and apply our proposed methodology.

• The Korean Journal of Applied Statistics
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• v.26 no.3
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• pp.431-440
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• 2013

We consider the problem of estimating the parameters of heavy tailed distributions. In general, maximum likelihood estimation(MLE) is the most preferred method of parameter estimation because it has good properties such as asymptotic consistency, normality and efficiency. However, MLE is not always the best solution because MLE is unstable or does not exist in some cases. This paper proposes another parameter estimation method, non-linear least squares(NLS) and compares its performance to MLE. The NLS estimator is achieved by minimizing sum of squared difference between empirical cumulative distribution function(CDF) and a theoretical distribution function. In this article, we compare the NLS method to MLE using simulated data from heavy tailed distributions. The NLS method is shown to perform better than MLE in Burr distribution when the sample size is small; in addition, it performs well in a Frechet distribution.

• Restorative Dentistry and Endodontics
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• v.41 no.4
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• pp.271-277
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• 2016

Objectives: In this study, we evaluated the influence of different radiant exposures provided by single-peak and polywave light-curing units (LCUs) on the degree of conversion (DC) and the mechanical properties of resin cements. Materials and Methods: Six experimental groups were established for each cement (RelyX ARC, 3M ESPE; LuxaCore Dual, Ivoclar Vivadent; Variolink, DMG), according to the different radiant exposures (5, 10, and $20J/cm^2$) and two LCUs (single-peak and polywave). The specimens were made (7 mm in length ${\times}$ 2 mm in width ${\times}$ 1 mm in height) using silicone molds. After 24 hours of preparation, DC measurement was performed using Fourier transform infrared spectrometry. The same specimens were used for the evaluation of mechanical properties (flexural strength, FS; elastic modulus, E) by a three-point bending test. Data were assessed for normality, after which two-way analysis of variance (ANOVA) and post hoc Tukey's test were performed. Results: No properties of the Variolink cement were influenced by any of the considered experimental conditions. In the case of the RelyX ARC cement, DC was higher when polywave LCU was used; FS and E were not influenced by the conditions evaluated. The LuxaCore cement showed greater sensitivity to the different protocols. Conclusions: On the basis of these results, both the spectrum of light emitted and the radiant exposure used could affect the properties of resin cements. However, the influence was material-dependent.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.71-77
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• 2017

In order for the consumers of education and university to be mutually communicating well, satisfaction surveys with a correct system are essential. This study points out the causes for insincere responses found in the process of education satisfaction surveys while discussing possible methods to elicit sincere responses from the students. As a result of analyzing S University, it was observed that enforced online evaluation methods did have a high response rate but also monotonously insincere responses showed to have a high ration among them. A second study was carried out in order to improve the research method after confirming the reliability of the research. Study results sowed that through a representative sample survey, monotonous response patterns decreased and the data distribution satisfied normal distribution. Moreover, a focus group interview was carried out in order to understand the root causes and possible solutions to the problem. Lastly, this study revealed the need of diversified attempts and research in order to secure reliability in education satisfaction surveys while proposing methods of improvement.

• The Journal of Advanced Prosthodontics
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• v.5 no.2
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• pp.110-117
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• 2013

PURPOSE. Polymethyl methacrylate (PMMA) is the most commonly used denture base material despite typically low in strength. The purpose of this study was to improve the physical properties of the PMMA based denture base resins (QC-20, Dentsply Ltd., Addlestone, UK; Stellon, AD International Ltd, Dentsply, Switzerland; Acron MC; GC Lab Technologies Inc., Alsip, Japan) by copolymerization mechanism. MATERIALS AND METHODS. Control group specimens were prepared according to the manufacturer recommendations. In the copolymer groups; resins were prepared with 5%, 10%, 15% and 20% acrylamide (AAm) (Merck, Hohenbrunn, Germany) content according to the moleculer weight ratio, respectively. Chemical structure was characterized by a Bruker Vertex-70 Fourier transform infrared spectroscopy (FTIR) (Bruker Optics Inc., Ettlingen, Germany). Hardness was determined using an universal hardness tester (Struers Duramin, Struers A/S, Ballerup, Denmark) equipped with a Vickers diamond penetrator. The glass transition temperature ($T_g$) of control and copolymers were evaluated by Perkin Elmer Diamond DSC (Perkin Elmer, Massachusetts,USA). Statistical analyses were carried out using the statistical package SPSS for Windows, version 15.0 (SPSS, Chicago, IL, USA). The results were tested regarding the normality of distribution with the Shapiro Wilk test. Data were analyzed using ANOVA with post-hoc Tukey test (P<.01). RESULTS. The copolymer synthesis was confirmed by FTIR spectroscopy. Glass transition temperature of the copolymer groups were higher than the control groups of the resins. The 10%, 15% and 20% copolymer groups of Stellon presented significantly higher than the control group in terms of hardness. 15% and 20% copolymer groups of Acron MC showed significantly higher hardness values when compared to the control group of the resin. Acrylamide addition did not affect the hardness of the QC-20 resin significantly. CONCLUSION. Within the limitation of this study, it can be concluded that copolymerization of PMMA with AAm increased the hardness value and glass transition temperature of PMMA denture base resins.

• Journal of Korean Society of Transportation
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• v.28 no.2
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• pp.21-32
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• 2010

A traffic island, typical channelization facilities, is widely applied to newly road designs and black spots improvement projects as traffic safety measures. However positive effects of a traffic island for traffic safety have not been reported specifically. Accordingly this study analyzed the accidents reduction effectiveness and economics of installing traffic islands under various roadways and traffic conditions. For this purpose normality test, paired t-test and Wilcoxon signed rank test were applied to this study based on traffic accidents, roadways and traffic environments data for 3 years before and after improvement at 54 intersections. The results showed that most of traffic accidents were reduced significantly after installing traffic islands except when traffic islands were installed in outside of cities and farming regions where use efficiency is low, curve sections with poor visibility, poor alignment sections with acceleration/deceleration lanes, road sections where occurs conflicts frequently due to did not install of acceleration/deceleration lanes, and road sections where cross with single lane road.

• The korean journal of orthodontics
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• v.51 no.3
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• pp.145-156
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• 2021

Objective: The aim of this retrospective study was to assess the midfacial soft tissue changes following maxillary expansion using micro-implant-supported maxillary skeletal expanders (MSEs) in young adults by cone-beam computerized tomography (CBCT) and to evaluate the correlations between hard and soft tissue changes after MSE usage. Methods: Twenty patients (mean age, 22.4 years; range, 17.6-27.1) with maxillary transverse deficiency treated with MSEs were selected. Mean expansion amount was 6.5 mm. CBCT images taken before and after expansion were superimposed to measure the changes in soft and hard tissue landmarks. Statistical analyses were performed using paired t-test and Pearson's correlation analysis on the basis of the normality of data. Results: Average lateral movement of the cheek points was 1.35 mm (right) and 1.08 mm (left), and that of the alar curvature points was 1.03 mm (right) and 1.02 mm (left). Average forward displacement of the cheek points was 0.59 mm (right) and 0.44 mm (left), and that of the alar curvature points was 0.61 mm (right) and 0.77 mm (left) (p < 0.05). Anterior nasal spine (ANS), posterior nasal spine (PNS), and alveolar bone width showed significant increments (p < 0.05). Changes in the cheek and alar curvature points on both sides significantly correlated with hard tissue changes (p < 0.05). Conclusions: Maxillary expansion using MSEs resulted in significant lateral and forward movements of the soft tissues of cheek and alar curvature points on both sides in young adults and correlated with the maxillary suture opening at the ANS and PNS.

• Journal of Korean Clinical Nursing Research
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• v.27 no.2
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• pp.130-139
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• 2021

Purpose: This study aimed to investigate the effect of educational nurse practitioners at comprehensive nursing care service units by comparing the educational satisfaction of general nurses and the occupational stress of preceptor nurses before and after education by educational nurse practitioners. Methods: Participants were 71 general nurses and 71 preceptor nurses working at comprehensive nursing care service units of G University hospital in I City. The level of educational satisfaction of general nurses and occupational stress of preceptor nurses were measured and compared. The differences in educational satisfaction and occupational stress before and after the education program were verified by paired t-test and one-way ANOVA using SPSS/WIN 27.0 statistical program. Differences before and after the education program according to the general characteristics were analyzed with repeated measure analysis of variance after Sapiro-Wilks normality test, and post-hoc analysis was conducted using Scheffétest. Results: It was inferred that there was a significant difference (t=-9.32, p<.001) in the educational satisfaction of general nurses, with an average of 3.72±0.77 before the education and 4.47±0.60 after the education. However, there was no significant difference in occupational stress in the preceptor nurses. Conclusion: It could be concluded that introduction of educational nurse practitioners at comprehensive nursing care service units has a positive effect on the educational satisfaction of general nurses. This result will serve as basic data to implement educational nurse practitioners for general nurses in all medical institutions as well as comprehensive nursing care service units.

• Women's Health Nursing
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• v.27 no.4
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• pp.337-347
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• 2021

Purpose: This study presents the development of a group video communication-based cognitive behavioral therapy (CBT) program for depressed pregnant women. It also provides the results of a preliminary test of its effects on their depression, automatic thoughts, and dysfunctional attitudes. Methods: In this quasi-experimental single-group pre- and posttest design study, 13 pregnant women participated in a 4-week, eight-session group CBT program, based on Beck's cognitive theory and using video communications from November 2020 to January 2021. Pregnant women between 14 and 32 weeks who were members of an online maternity and parenting community and residing in the cities of Changwon and Gimhae, Korea, were invited to voluntarily participate. Trained nurses led CBT sessions of 3-4 participants per group via video communication. Participants were assessed pre- and postintervention with self-report questionnaires for measurement of depression, automatic thought, and dysfunctional attitude after normality test according to the Shapiro-Wilk test of the variables. The data were analyzed using paired t-test and Pearson correlation coefficients. Results: Depression (t=7.90, p<.001), automatic thoughts (t=4.89, p<.001), and dysfunctional attitudes (t=2.42, p=.032) significantly decreased after the 4-week online program. There were statistically significant correlations among the three variables. Conclusion: This program was found to be effective in reducing depression, automatic thoughts, and dysfunctional attitudes. Above findings suggest that a group CBT program using video communication can be an effective therapeutic modality that helps pregnant women at risk for depression alleviate their negative emotions related to depression.