• Communications for Statistical Applications and Methods
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• v.18 no.6
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• pp.751-759
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• 2011

The method of generalized estimating equations(GEE) is widely used in the analysis of a correlated dataset that consists of repeatedly observed responses within subjects. The GEE uses a quasi-likelihood equations to find the parameter estimates without assuming a specific distribution for the correlated responses. In this paper we study the importance of specifying the working correlation structure appropriately in fitting GEE for correlated counts data. We investigate the empirical coverages of confidence intervals for the regression coefficients according to four kinds of working correlations where one structure should be specified by the users. The confidence intervals are computed based on the asymptotic normality and the sandwich variance estimator.

• The Korean Journal of Applied Statistics
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• v.26 no.5
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• pp.697-712
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• 2013

When analyzing repeated binary data, the generalized estimating equations(GEE) approach produces consistent estimates for regression parameters even if an incorrect working correlation matrix is used. However, time-varying covariates experience larger changes in coefficients than time-invariant covariates across various working correlation structures for finite samples. In addition, the GEE approach may give biased estimates under missing at random(MAR). Weighted estimating equations and multiple imputation methods have been proposed to reduce biases in parameter estimates under MAR. This article studies if the two methods produce robust estimates across various working correlation structures for longitudinal binary data with time-varying covariates under different missing mechanisms. Through simulation, we observe that time-varying covariates have greater differences in parameter estimates across different working correlation structures than time-invariant covariates. The multiple imputation method produces more robust estimates under any working correlation structure and smaller biases compared to the other two methods.

• Journal of Korean society of Dental Hygiene
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• v.2 no.2
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• pp.131-143
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• 2002

The purpose of this study was to investigate the relationship of empowerment, self-efficacy, and turnover intention of dental hygienists. Date were obtained from 213 dental hygienists who were working at dental clinics, hospitals located in Seoul Kyung-ki. The results were analyzed with spsswin 9.0 and the conclusion is as follows; 1. The level of dental hygienists empowerment was 3.07, self-efficacy was 3.67, and their turnover intention was 2.98. 2. According to the working place and position, there were significant differences in empowerment(p<0.05). 3. According to the experienced-years, position, marriage and turnover experience there were significant differences in self-efficacy(p<0.05). 4. According to the position and marriage, there were significant differences in turnover intention(p<0.05). 5. Empowerment showed significant a positive correlation with self-efficacy and significant a negative correlation with turnover intention. 6. Turnover intention, information structure and opportunity structure accounted significantly for the empowerment structure and self-efficacy. 7. Self-efficacy and GE structure accounted significantly for the turnover intention.

• Journal of the Korean Home Economics Association
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• v.25 no.4
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• pp.33-45
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• 1987

The purpose of this study is to analyze the factorial structure of the criteria on clothing selection of the working women, and then to provide the date to develop an instrument to measure the criteria on clothing selection. A total of 877 samples were selected from unmarried female in the twenties. Data were analyzed using factor analysis, Pearson's product-mement correlation coefficients, content analysis and Cronbach's α. The results of the study were as follows; 1. There were identified 7 factors as the clothing selection criteria of the working women; Fashion, Practicality, Modesty, Appearance, Service, Comfort, and Impulse purchase. 2. Comparing with the previous results, we confirmed that the criteria on clothing selection was made up of at least 8 factors; Practicality, Comfort, Brand or price, Impulse purchase, Fashion, Individuality, Modesty, and Service. 3. According to the correlation among 8 factors, they formed two clusters; one cluster contained Practicality, Comfort, and Modesty factor, and the other did Brand or price, Impulse purchase, Fashion and Individuality factor. 4. Service factor was significantly correlated to the other factors, that is, service was the very important criteria on the clothing selection.

• Journal of Korean Academy of Nursing Administration
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• v.18 no.4
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• pp.452-459
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• 2012

Purpose: This study was a descriptive study conducted to investigate the effects of intellectual capital on organizational performance of nurses in medium and small hospitals. Methods: Data were collected from 241 nurses working in medium and/or small hospitals located in G City from August 10 to September 17, 2011. The measurement tools were the Intellectual Capital scale and Organizational Performance scale. Data were analyzed using frequency, percentage, mean, standard deviation, t-test, one way ANOVA, Pearson correlation, and hierarchical regression with SPSS WIN 18.0 PC. Results: Intellectual capital composed of human, customer, and structure capital had significant effects on organizational performance of nurses working in medium and small hospitals and explained 50.4% of the variance. Conclusion: In order to promote organizational performance of nurses, nursing managers and administrators need to invest more resources into the intellectual capital of the system including human, customer, and structure capital.

• Journal of Korean society of Dental Hygiene
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• v.5 no.1
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• pp.77-88
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• 2005

The purpose of this study was to investigate the relationship of power and empowerment, self-efficacy of dental hygienists. Date were obtained from 203 dental hygienists who were working at dental clinics, hospitals located in Seoul. The results were analyzed with spsswin 12.0 and the conclusion is as follows: 1. The level of dental hygienists formal power was 3.19, informal power was 3.41, empowerment was 3.12, self-efficacy was 3.67. 2. Formal power showed significant a positive correlation with informal power and informal power showed significant a positive correlation with empowerment 3. According to the position, there were significant differences in formal power(pE0.05). 4. According to the working place, age, experienced-years, position, marriage and turnover experience there were significant differences in informal power(pE0.05). S. According to the working place, position, and marriage there were significant differences in empowerment(pE0.05). 6. According to the age, experienced-years, position, marriage and turnover experience there were significant differences in self-efficacy(pE0.05). 7. Informal power and information structure accounted significantly for the self-efficacy.

• Journal of the Korea Safety Management & Science
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• v.24 no.3
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• pp.39-46
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• 2022

This study has found the socio-economic factors that affect occupational accidents and measured the influence quantitatively. We built the panel data of 4 countries (Japan, Germany, the U.S., and the U.K.) and the analysis model counted on the fixed effect model to reflect the countries' differences. The fatal occupational injury rates in the analyzed countries had a statistically significant relationship with the level of per capita GDP, the proportion of the construction industry, the rate of male workers, annual average working hours, the rate of workers in manufacturing and construction industries, etc. The annual average working hours have a positive correlation with the fatal occupational injury rate. To reduce occupational accidents effectively, we should be monitoring and researching various factors that can affect the occurrence of occupational accidents such as worker characteristics, changing industrial structure, and changes in working hours.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.658-662
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• 2004

This paper proposes an orthogonal reception structure for OS/SS communication with time-shifted m-sequences, and compares the performances of the proposed and conventional receiver. This structure provides two important characteristics to reference user signal with not only increment of auto-correlation value but also cancel of the cross-correlation value out to zero between the reference user and other user signals. In addition, the structure can be easily implemented with the conventional receiver adding an additional integrator path in parallel and an adder that sums the conventional path output and the new path output signal. Hence, the proposed structure can be applied for channel impulse response measurement, and efficiently used for multi-user interference signal cancellation and channel capacity increment by flexible structural inter-working operation, connection or disconnection, of the new path to conventional receiver structure.

• Journal of Korean society of Dental Hygiene
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• v.9 no.3
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• pp.329-343
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• 2009

Purpose : This study was to figure out the factors affecting the job satisfaction of dental hygienists working in dental clinics. To gain the data to establish the systems for enhancing the job satisfaction of the dental hygienists. This research has been conducted dental hygienists working in dental clinics institutes located in Jeonju and Iksan city, Jeollabuk-do, korea. Methods : The collected data were analyzed by using an SPSS statistical program, obtaining the following results. Result : The average satisfactory level of the dental hygienists was 3.45 out of 5 points. The most important factor affecting of the job satisfaction was the relationship with patients as 3.83 points and the least influencing factor was the compensation as 3.09 points. The management system and the satisfactory level were also correlated. For each of details, communication structure and working environment showed the highest correlation with Pearson's correlation coefficient of 0.610. Among the management system the general job satisfaction according to the communicational structure was higher when they had better communication with dentists. Among the management system, the job satisfaction according to structural factors was higher when they have manuals for the job, when their job is taken partial charge of the responsibility As for job satisfaction by the welfare support factor in the clinic management system, the better an informal social gathering, the higher general job satisfaction. As for job satisfaction by the job autonomy factor in the clinic management system, the more evenly distributed job opportunities and chances of reeducation for professional development led to higher general job satisfaction. Conclusion : The compensation-related grade was the lowest among the 6 constituent factors of the job satisfaction, it seems that improvement of wages and incentives is required to enhance the satisfaction of the dental hygienists. Also, improving factors affecting the management system of the dental service institute can increase the job satisfaction since the job satisfaction was higher when the institutes have the better management system.

• Smart Structures and Systems
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• v.24 no.5
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• pp.597-606
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• 2019

Damage detection based on dynamic characteristics of a structure is one of important roles in structural damage identification. It is difficult to detect local structural damage using traditional dynamic experimental methods due to a limited number of sensors used in an experiment. In this work, a non-contact test stand of fan blades is established, and a full-field noncontact test method, combined with three-dimensional digital image correlation, Bayesian operational modal analysis, and damage indices, is used to detect local damage of a fan blade under ambient excitation without use of baseline information before structural damage. The methodology is applied to detect invisible local damage on the fan blade. Such a method has a seemingly high potential as an alternative to detect local damage of blades with complex high-precision surfaces under extreme working conditions because it is a noncontact test method and can be used under ambient excitation without human participation.