• Journal of Power Electronics
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• v.4 no.2
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• pp.65-76
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• 2004

In this paper, the steady-state analysis of the three-phase self-excited induction generator (SEIG) driven by a variable-speed prime mover (VSPM) such as a wind turbine is presented. The steady-state torque-speed characteristics of the VSPM are considered with the three-phase SEIG equivalent circuit for evaluating the operating performances due to the inductive load variations. Furthermore, a PI closed-loop feedback voltage regulation scheme based on the static VAR compensator (SVC) for the three-phase SEIG driven by the VSPM is designed and considered for the wind power generation conditioner. The simulation and experimental results prove the practical effectiveness of the additional SVC with the PI controller-based feedback loop in terms of fast response and high performances.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.1-9
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• 2022

Recently, a large number of cryptocurrencies and block chains have been continuously released. However, these cryptocurrencies and block chains are open to users without authorized verification and testing procedures, causing various reliability problems. Existing cryptocurrencies and blockchain test methods build a blockchain Testnet for a certain period of time by the developer without external verification by a third party, and after repeatedly self-testing and self-operating processes, commercialization is in progress by switching to the Mainnet. This self-verification method does not guarantee objectivity and publicness, and high reliability of customers cannot be realized. This study proposes a cryptocurrency and blockchain test interface and test control system as a third-party open test method.

• The Korean Journal of Health Service Management
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• v.11 no.2
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• pp.105-115
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• 2017

Objectives : The aim of this study was to suggest the optimal cut off for best, very good, good, slightly bad, and bad grades. Methods : The subjects were recruited from 4 areas of South Korea and 487 questionnaires were analyzed. The nominal and continuous self-rated health questions were used to reveal the optimal cut off and the Short Form-12 Health Survey questionnaire (SF-12) was additionally used. Frequency, Pearson's correlation coefficient, and ROC-curve analysis were used; the significance level was <.05. Results : Subjects assigned 15(3.1%), 90(18.5%), 237(48.7%), 130(26.7%), and 15(3.1%) to best, very good, good, slightly bad and bad groups respectively. The self-rated health score was associated with total Component (r=.563, p<.001), Physical Component (r=.520, p<.001) and Mental Component of SF-12 (r=.303, p<.001). The optimal cut off was 80.5, 70.5, 53.5, and 40.5 for best, very good or more, good or more, and under slightly bad respectively and area under curve was 0.898, 0.908, 0.945, and 0.908 accordingly. Conclusions : This study suggests that the self-rated health score and grade could be integrated with the optimal cut off.

• Journal of Family Resource Management and Policy Review
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• v.22 no.2
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• pp.1-24
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• 2018

Communal places for parents to take child-care are very important in activating cooperative child-care(CCC). Therefore, Jeju Special Self-Governing Province has been operating Cooperative-Childcare-Places(CCPs) since 2016. This study analyzed the operational status of the CCPs and presented the model type to provide data for the activation of CCC. Qualitative analyses were applied to the results of interviews with 10 staff members. The common task they considered difficult was recruitment, and there was a big difference in the operation of the regular program depending on the competence of the staff in charge. The lack of support systems, such as education and consulting, has made it difficult for the staff to do their work. Additionly, four models of CCPs were found, a resident self-governing type, a workplace type, an institutional type, and a rural complex type. In conclusion, CCP spaces should be planned and facilities created with a focus on the needs of child-care activities. Second, the role of staff in helping to organize the parents' self-governing committee is crucial. Third, it needs to establish a support system to strengthen the capacity of the staff members.

• International Journal of Precision Engineering and Manufacturing-Green Technology
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• v.5 no.5
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• pp.643-650
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• 2018

A self-powered electrochromic device was fabricated on an indium tin oxide-polyethylene naphthalate flexible substrate using a dye-sensitized solar cell (DSSC) as a self-harvesting source; the electrochromic device was naturally bleached and operated under outdoor light conditions. The color of the organic electrochromic polymer, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, was shifted from pale blue to deep blue with an antimony tin oxide film as a charge-balanced material. Electrochromic performance was enhanced by secondary doping using dimethyl sulfoxide. As a result, the device showed stable switching behavior with a high transmittance change difference of 40% at its specific wavelength of 630 nm for 6 hrs. To improve the efficiency of the solar cell, 1.0 wt.% of Ag NWs in the photoanode was applied to the $TiO_2$ photoanode. It resulted in an efficiency of 3.3%, leading to an operating voltage of 0.7 V under xenon lamp conditions. As a result, we built a standalone self-harvesting electrochromic system with the performance of transmittance switching of 29% at 630 nm, by connecting with two solar cells in a device. Thus, a self-harvesting and flexible device was fabricated to operate automatically under the irradiated/dark conditions.

• International Journal of Advanced Culture Technology
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• v.9 no.4
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• pp.9-17
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• 2021

This is a descriptive investigative study which attempts to confirm the mediating effect of learning motivation in the relationship between self-directed learning, learning commitment, and learning persistence intention of university students in an online learning environment. The questionnaires were randomly distributed online and the agreed questionnaires were retrieved, with a total of 338 copies used for analysis. The following is the summary of the findings. First, there were significant differences in learning persistence intention according to general characteristics depending on age, major, part-time job, and academic level. Second, the results showed a positive correlation between self-directed learning, learning commitment, learning motivation, and learning persistence intentions of the subjects were statistically significant. Third, after checking the mediating effect of learning motivation in relation to self-directed learning, learning commitment and learning motivation, the learning motivation has a partial mediating effect on learning and 23% explanatory power, and the learning commitment was found to have a complete mediating effect on the impact of learning motivation on learning intentions with 21% explanatory power. Based on these results, it is necessary to provide a more diverse educational environment, such as operating a motivation semester program that can improve learning motivations along with learning commitment, and the use of a variety of contents that can focus the learner's interest or attention.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.30 no.3
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• pp.54-64
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• 2022

Airlines have been introducing self check-in kiosks to reduce check-in time and improve operational efficacy to increase business revenue. The domestic airlines have actively provided kiosks at airports which are expected to reduce their operating costs and enrich their passengers' travel convenience. Based on the above background, the study investigates the factors influencing intention to use the self check-in kiosks by employing the Extended Technology Acceptance Model (ETAM). The study, therefore, designed a research model by reviewing theories and studies on the relationship among information quality, innovativeness, perceived ease of use, perceived usefulness, and intention to use the kiosks. The structural equation model revealed the following. Information quality and innovativeness had a significantly positive influence on perceived ease of use and perceived usefulness; furthermore, perceived ease of use had a significantly positive influence on perceived usefulness. In addition, both perceived ease of use and perceived usefulness had a significantly positive influence on intention to use. The results indicate that the airlines should constantly develop user-friendly contents and design of the self check-in kiosks.

• Journal of Digital Convergence
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• v.12 no.8
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• pp.449-458
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• 2014

The purpose of this study was to examine and analysis self-help group program performed in community-based home visiting health service. The data was collected public servants from the Home Visiting Health Care Service of 253 public health centers all over the country and was analyzed by SPSS/Win 17.0 program. 43.1% of self-help program was performed and 56.9% was not from year 2007 to 2010. As the years passed, the number of self-help group program was getting increased. The action for activating self-help programs was voluntary participation of clients, enthusiasm of management practitioner, and encouragement about self-help group. Self-help group programs based on public health center are insufficient. Self-help programs should be activated for clients of home visiting health care service. A systematic operating model of self-help group is also needed to develop and apply in consideration of these findings.

• Fashion & Textile Research Journal
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• v.20 no.3
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• pp.279-286
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• 2018

This study conducted a qualitative research based on interviews with school teachers and instructors operating external activities about how the management of one's own appearance influence the changes in subjective happiness and self-esteem by focusing on maladjusted students of two alternative schools and ordinary middle and high schools in Gyeongsangnam-do province. Happiness refers to a positive emotion that can be felt continuously throughout life such as life satisfaction, good experience, and positive way of thinking. The sense of happiness is the satisfaction that one feels by interpreting and evaluating his or her experience in a positive way and can be defined as the positive emotions that can be felt when one perceives and uses the strengths and resources that he or she has. Although the self-esteem is formed, changed, and developed throughout life, the self-awareness and self-evaluation develop more actively than other stages of development particularly in adolescence, and the adolescents with low self-esteem are faced with more serious behavioral, scholastic, and psychological issues. I hope the results of this study not only help current adolescents at risk to improve their self-esteem but also become a chance to see the issue of adolescents at risk as a part of social issue instead of limiting the issue as personal or domestic issue by expanding the application scope of the results to adolescents in middle schools and high schools who have the potential of going astray in order to approach the issue on the level of the entire society.

• Korean Journal of Community Nutrition
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• v.10 no.3
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• pp.331-340
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• 2005

The purpose of this study was to provide basic data to improve college food service satisfaction with sanitary, environment and service by comparing 2 contract-managed and 2 self-operated college food services in Daejeon and Chungnam area. According to the results, sanitation and environment satisfaction degrees of contract-managed college food services were higher than those of self-operated food services. The satisfaction degrees with service were also higher in contract-managed food services than self-operated food services except the category of quick food delivery. In all categories comprising the food service satisfaction, the satisfaction degrees were lower in female students than in male students. There were more negative self-perceived clinical symptoms in female students than male students. The higher the negative self-perceived clinical symptoms scores were, the lower the satisfaction degrees with food service were, which suggests that かe health state of students was one of the factors that influenced college food service satisfaction. There was no difference between contract-managed and self-operated food services in terms of satisfaction with overall food taste and overall satisfaction degree. The average satisfaction degree for the contractmanaged food services in terms of price relative to food quality was lower than that for self-operated food services. According to stepwise multiple regression analysis, 'overall food taste', 'price relative to quality', 'kindness of employees', 'coping with proposed opinions' and 'quicknless of food delivery' in decreasing order, were the most relatively important attributes for overall satisfaction. There should be further studies on important management factors to improve satisfaction with sanitary, environment and service by self-operated college food service.