• Journal of ILASS-Korea
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• v.9 no.3
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• pp.15-21
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• 2004

The removal of the dusts in the subway stations, tunnels, factories and buildings becomes issue for comfortable indoor and outdoor conditions. There has been used an automatic self-cleaning filter system to collect the dusts. In general, the collected particles are removed by water spray nozzles. The new design for improving the cleaning efficiency of collected dusts and reducing the supplied water is the concept of the plane array of demister filters and the twin-fluid nozzle for mixing compressed air and water in the automatic self-cleaning filter system. Results show that the cleaning efficiency of twin-nozzle filter systems is 99.1%, compared to 47% in the conventional filter system. Therefore the automatic self-cleaning filter system using twin-fluid nozzle filter systems reduces water supplied in the filter system, and increases cleaning efficiency and drying efficiency.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.2
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• pp.134-141
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• 2004

This paper presents a method of synchronous rectifier(SR) for improving the efficiency in DC/DC converter. The proposed method is used push-pull topology on primary as a single winding self driven synchronous rectification(SWSDSR). Specially, this method can improve efficiency to turn on SR switch during dead time. Finally, the simulation and experimental results will be given to show comparison and analysis on the efficiency between self driven synchronous rectification(SDSR) and SWSDSR method.

• Journal of the East Asian Society of Dietary Life
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• v.23 no.6
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• pp.862-870
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• 2013

This study examines the effect of communication type of food service employees on the self-efficiency and organizational commitment. To accomplish the purpose of the study, a survey was conducted to employees of food service companies located in Seoul, from August 5, 2013 to August 25, 2013 as a method of empirical study. The results of this study was analyzed using the SPSS WIN 12.0 and statistical reliability analysis, factor analysis, frequency analysis, correlation analysis and multiple regression analysis were conducted for hypothesis verification. The analysis results of this study are as follows. First, the R-square of regression result for 'communication type will have a positive effect on self-efficiency' was .220. Also, it was found that factors of consideration (Beta=.286, t=5.622), instruction (Beta=.303, t=5.970) and business (Beta=.214, t=4.217) had positive effects on self-efficiency. Values for factors of consideration and instruction were higher than business. Second, the R-square of regression result for 'communication type will have a positive effect on organizational commitment' was .429. Also, it was found that factors of consideration (Beta=.453, t=10.428), instruction (Beta=.380, t=8.749) and business (Beta=.282, t=6.477) had positive effects on organizational commitment. Values for factors of instruction and business were high but value of consideration factor turned out the highest. Third, the R-square of regression result for 'self-efficiency will have a positive effect on organizational commitment' was .334. Also, it was found that out of the factors of positivity (Beta=.369, t=8.423), confidence (Beta=.415, t=8.833) and negativity (Beta=-.072, t=-1.536), positivity and confidence had positive effects on organization commitment, and only positivity and confidence showed high values in organization commitment. Upon analyzing the effect of factors of self-efficiency (positivity, confidence, negativity) on organizational commitment, it was found that positivity and confidence showed high relevance but the negativity factor did not have any correlation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.121-128
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• 2017

This paper was to evaluate social enterprises' management efficiency with Data Envelope Analysis (DEA). The data was based on the 168 social enterprises' of annual performance reports published in 2015. The research focused on to measure both financial efficiency and social impact of the companies simultaneously. To apply DEA, the paper classified the enterprises into seven types based on types of socal impacts which each company provides before the estimation of the efficiency. The research results showed that group D, which employes disadvantaged people, provides social services and shares resources was the most efficient group and had higest net worths in Pure Technical Efficiency. In contrast, Group B, which only employs social advantage people and provides social service, was the least efficient one. The research suggests a practical and efficient framework in measuring social enterprises' management efficiency, including both the financial performance and social impacts simultaneously with their self-publishing reports. Because the Korea Social Enterprise Promotion Agency does not open business reports which social enterprises submit each year, there are basic limitations on researchers attempting to analyse with data from all social enterprises in Korea. Thus, this study dealt with only 10% of the social enterprises which self-published their performance report on the Korea Social Enterprise Promotion Agency's web site. Regardless of these limitations, this study suggested substantial methods to estimate management efficiency with the self-published reports. Because self-publishing is increasing each year, it will be the main source of information for researchers in examining and evaluating social enterprises' financial performance or social contribution. The research suggests a practical and efficient framework in measuring social enterprises' management efficiency, including both the financial performance and social impacts simultaneously with their self-publishing reports. The research results suggest not only list of efficient enterprises but also methods of improvement for less efficient enterprises.

• Elastomers and Composites
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• v.50 no.3
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• pp.167-174
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• 2015

Anionic epoxy compound was synthesized and added to asphalt aiming to prepare self-healing asphalt. Epoxy-modified asphalt showed excellent modification effect and healing effect as well. The results revealed that with 5% addition of polymer the tensile strength, impact strength and complex shear modulus of the polymer-modified asphalt increased by 65%. 64% and 35%, respectively. It seems that high interaction occurs between polymer and asphalt matrix. Self-healing efficiency of the polymer-modified asphalt based on tensile strength showed 100%, comparing to 79% of straight asphalt. In impact experiment the polymer-modified asphalt showed 99% of healing efficiency, comparing to 77% of straight asphalt. In rheological experiment the polymer-modified asphalt showed 103% of healing efficiency, comparing to 72% of straight asphalt. It appears that the ionic bonding existing in epoxy polymers contributed to high values of self-healing efficiency. The polymer which has high intermolecular force fills the crack of the asphalt, pulling the opponent side each other, and so the original properties were restored.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.371-378
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• 2024

This study attempted to understand how the communication efficiency of middle-aged couples affects marriage satisfaction and to verify the mediating effect of self-esteem. To this end, the results of analyzing the influence relationship between the variables by collecting questionnaire data on the variables of 421 middle-aged couples living in D city are as follows. First, it was confirmed that the communication efficiency, self-esteem, and marriage satisfaction of middle-aged couples had a positive relationship. Second, the partial mediating effect of self-esteem in the relationship between marriage satisfaction was verified by the communication efficiency of middle-aged couples. Based on these research results, an action plan to improve marriage satisfaction in the middle-aged part was suggested.

• Journal of Power Electronics
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• v.15 no.3
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• pp.634-643
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• 2015

This paper presents a high frequency design approach for improving efficiency over a wide load range in the self-driven phase-shifted full-bridge converters for server power systems. In the proposed approach, a detailed ZVS analysis of the lagging leg switches in both the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM) is presented. The optimum dead time and the determination of the appropriate operation mode are given for high efficiency according to the load conditions. Finally, the optimum operation conditions are defined to achieve a high-efficiency. A laboratory prototype operating at 80 kHz, rated 1 kW (12 V-83.3 A), is built to verify proposed theoretical analysis and evaluations. The experimental results show that the maximum efficiency is achieved as 95% and 83.5% at full load and 5% load conditions, respectively.

• Journal of Families and Better Life
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• v.28 no.3
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• pp.97-112
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• 2010

This study is designed to find out the effect of communication between parents and adolescents, and their goal orientation on academic self-efficacy, especially among second-year high school students based on all their family and social environments. For such purposes, a variety of data regarding background variables, communication between parents and adolescents, goal orientation, and academic self-efficacy were collected in Seoul and Goyang-si, Gyunggi-do. The major results of this study are as follows: First, the female high-school students showed a higher efficiency than the male ones when it comes to the communication between parents and adolescents. For the goal orientation, the girl students marked higher levels than the male counterparts; speaking of self-regulated efficiency, the former illustrated a much higher level than the latter as well. Second, academic self-efficacy is greatly influenced by goal orientation. The higher mastery and performance-approach goals are, the higher academic self-efficacy is. It has turned out that mastery goals have significant relationship with task difficulty performance, one of the sub-scales of academic self-efficacy. In addition, performance-approach goals proved to be deeply connected with self-regulated efficiency, but performance-avoidance goals were negative predictors of task difficulty performance and self-regulated efficiency. In turn, academic confidence, one of the sub-scales of academic self-efficacy, is believed to be under the influence of mastery goals and communication between fathers and adolescents.

• The Korean Journal of Health Service Management
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• v.7 no.4
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• pp.23-32
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• 2013

This study aimed to explore possible relationships between self-efficiency and intention to leave in dental hygienists so as to provide basic data for developing solutions to effectively manage dental hygienist man power. A total of 206 dental hygienists from different dental care institutions in Cheonbuk Province were chosen as subjects by a convenience sampling method. Data were collected through a self-reported survey. The results were as follows. The self-efficiency was higher among dental hygienists who were more than 36 years of age, had graduated university, were at their cuurent job longer than 11 years, and reported their annual income to be more than 25 million won. As their age was younger and their education and income levels were lower, their intention to leave was stronger. Also subjects who were unmarried, did not feel satisfaction with their current job, and did not want to stay any longer at the location where they were currently working tended to have higher intention to leave. The higher their self-efficiency, the lower their turnover intention. An examination of the three factors offered by a factor analysis on self-efficiency, 1) sense of competence, 2) sense of confidence, and 3) strong drive, revealed that the higher their sense of competence, the lower their turnover intention. It was also revealed that their self-efficiency had a significant influence on their turnover intention and the most influential factor was their sense of competence.

• Journal of Power Electronics
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• v.16 no.1
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• pp.121-132
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• 2016

In this paper, high-efficiency design methodology of a zero-voltage-switching full-bridge (ZVS-FB) pulse width modulation (PWM) converter for server-computer power supply is discussed based on self-driven synchronous rectifier (SR) performance. The design approach focuses on rectifier conduction loss on the secondary side because of high output current application. Various-number parallel-connected SRs are evaluated to reduce high conduction loss. For this approach, the reliability of gate control signals produced from a self-driver is analyzed in detail to determine whether the converter achieves high efficiency. A laboratory prototype that operates at 80 kHz and rated 1 kW/12 V is built for various-number parallel combination of SRs to verify the proposed theoretical analysis and evaluations. Measurement results show that the best efficiency of the converter is 95.16%.