• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.4
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• pp.198-203
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• 2013

There are conditions that can be unbalanced three phase currents in a large generator by untransposed lines, unbalanced loads, unsymmetrical faults, and open phases. The unbalanced conditions can producing negative sequence components of current that induce two times frequence current in the surface of the rotor, the retaining rings, the slot wedges in the field windings. These rotor currents make the rotor rapidly overheat, so the rotor can cause substantial damage in a very short time. This paper presents the digital negative sequence relay algorithm for unbalanced protection in a generator. The proposed algorithm was tested by using collected current signals on PSCAD/EMTDC considering a hydro turbine based generator control system. It can be seen that the proposed relaying by negative sequence current is useful for detection of unbalanced state of large generator.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.5
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• pp.66-74
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• 1996

In this paper, the arc currents, voltages and these waveforms were investigated when negative DC high voltages applied to neddle-pane electrodes to study arc quenching phenomena of DC interruption in the. magnetic field. The conclusion of this study are as follows : There are no dynamic arc characteristics in the no magnetic field. Not only dynamic arc characteric but also zero points of arc current which are generated from repeating frequence of arc discharge under the magnetic fields were observed. The more magnetic field were applied, the repeating frequence of arc discharge were more increased..

• Journal of Ocean Engineering and Technology
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• v.20 no.3 s.70
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• pp.1-6
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• 2006

Modulation theory describes propagation of surface waves with deep wave number and frequency modulation. Locally spectrally narrow wave packet can have accumulated large scale frequency shift of carrier wave during propagation. Some important nonlinear modulation effects, such as negative frequencies, phase kinks, crest pairing, etc., often observed experimentally at long fetch propagation of finite amplitude surface wave trains, are reproduced by the proposed theory. The presented model permits also to analyze the appropriately short surface wave packets and modulation periods. Solutions show the wave phase kinks to arise on areas' of relatively small free surface displacement in complete accordance with the experiments.

• Fashion & Textile Research Journal
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• v.18 no.5
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• pp.625-636
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• 2016

The purposes of this study were to investigate the effects of social appearance anxiety, negative body image, appearance importance on appearance management behavior and cosmetic surgery intention. For data collection, a questionnaire was administrated to 428 female college students in Gwangju City, Korea. The results were summarized as follows. To analysis the data, the SPSS 20.0 was used, and frequence analysis, descriptive statistical analysis, reliability analysis, regression analysis, F-test were conducted. The results were summarized as follows. First, social appearance anxiety turned out to have significant positive effect on appearance management behavior and cosmetic surgery intention. Second, negative body image had positive effect on appearance management behavior and cosmetic surgery intention. Third, appearance importance turned out to have significant effect on appearance management behavior and cosmetic surgery intention. The results of this study above suggest that it would be necessary to seek for measures to reduce individual's appearance anxiety, negative body image, and appearance importance. Especially, People should get the realization of the beautiful on the inside that includes personality is more important than having external beauty. And, it is considered that the requirements of the social effort and education through a school and a media as well as a family for reducing the individual's appearance anxiety, negative body image, and the serious consideration of the appearance as rejecting the discrimination based on appearance.

• Journal of Korean society of Dental Hygiene
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• v.7 no.3
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• pp.231-245
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• 2007

This study aims to discuss plans to improve the satisfaction level of dental services by understanding characters of beliefs about dental manpower and analyzing its related factors. Data were collected by structured questionnaire whose subjects consist of 1607 persons from 13 years old to 69 years old, who have ever experienced dental institution. Both univariate and biovariate analyses were employed to analyze level of dentist and dental hygienist's beliefs and its related factors and the results gained from the surveys and search are as follows. 1. Among the questions to measure dentist's beliefs, 'Respect for patients' was evaluated as the best, and the lowest items were 'not-hopeful explanation about prognosis of dental treatment', 'satisfactory explanation' and 'whether treatments are stopped by pains or not'. In addition, among questions to measure dental hygienist's beliefs, 'kindly welcome' and 'detailed explanations about medical directions' are the items evaluated as the best and 'notice of waiting time' marked the lowest evaluation. 2. The factors related to beliefs about dentists were age, ache experiences, dental fear, self-reported dental health status, frequence and primary purposes of the visits dental institutions, elapsed time from recently visited, present of favorite dental clinic to visit regularly. 3. The factors related to beliefs about dental hygienists were age, education, occupation, ache experiences, frequence and primary purposes of the visits dental institutions, periodic check of teeth, present of favorite dental clinic to visit regularly. 4. Direct painful, painful treatment experience under insufficient local anesthetic, indirect painful experience and dental fear were positively correlated. And the relationships were positive between ache experiences, dental fear and self-reported dental health status, but relationships were negative between ache experiences, dental fear and dentist! dental hygienist's beliefs.

• Journal of Families and Better Life
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• v.8 no.2
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• pp.15-30
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• 1990

The purpose of this study are 1) to offer the basic data for consumer education by examining and analyzing housewife's Life Style. 2) to make the housewife lead for Life Style better and more resonable. Questionnaires were sent to 623 housewives in Pusan who have elementary , middle and high school students. Frequence, Factor analysis, Cluster analysis, One-way Anova, X 2-test were used to take statistics. The results were as follows. 1) Housewife's Life Style in independent house area were ' the economical seeking pattern' which takes up th high proportions, next 'the practical reserved seeking pattern' ,'the tradition and reservational fashion seeking pattern', and 'the negative neverlessness pattern' On the other hand, the Life-Style in apartment area were' the rapid purpose seeking pattern', next ' the economical seeking pattern', the fashion and pleasure seeking pattern' and 'the tradition and reservational fashion seeking pattern'. 2) By surveying the relationships the housewife's Life Style and the demographics, first, there was a difference in housewife's Life Style of the independent house area by the level of education, monthly mean income and husbands occupation. 3) Finally, as I studied th characterization of which they possessed thing, it usually appeared the characteristic possession by types.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.3
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• pp.1-13
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• 2019

The study examines preference between rural bus and call-a-bus before call-a-bus operation and empirically analyzes the effecting factors on the call-a-bus satisfaction after operation. As the result of log-linear model, older persons prefer call-a-bus because of door-to-door service convenience and female also because of limitation of trip moving means. It is shown that persons with lower number of trips prefer call-a-bus. As the result of ordinal regression model for call-a-bus satisfaction, age, the number of family members and bus stop distance have the positive tendency but the going out frequency and the return time negative among rural bus preference persons. Male and the going out frequence show the negative tendency but trip moving means, bus stop distance, rural bus satisfaction, depart and return time positive among call-a-bus preference persons. The persons who have the positive preference on call-a-bus shows higher satisfaction on call-a-bus.

• Journal of Periodontal and Implant Science
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• v.33 no.2
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• pp.159-166
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• 2003

The purpose of this study was to investigate and compare the frequence of 4 periodontal pathogens in the supra- and subgingival plaque in periodontally healthy subjects. Twenty adult individuals aged 22 to 28 years (mean age 23.65 years) participated in this study. All subjects had no pocket sites more than 3 mm deep, and the sites selected for sampling were all negative for bleeding. After drying and isolation of the sites with cotton rolls, supragingival plaque was sampled using sterile periodontal curette. Each plaque sample was placed in individual tubes containing 500 ml of 1X PBS. After removal of the supragingival sample and any remaining supragingival plaque, subgingival plaque samples were taken from the same sites using sterile curette and placed in similar individual tubes. Identification of 4 putative periodontal pathogens from the samples was performed by polymerase chain reaction based on 16S rDNA. Chi-square test was employed to identify significant explanatory variables for the presence of the 4 periodontal pathogens. The data show that Actinobacillus actinmycetemcomitans, Porphyromonanas gingivalis, Bacteroides forsythus, and Fusobacterium nucleatum occurred in 16.9%, 14.4%, 52.5%, and 80.6%, respectively. No significant differences were noted in the periodontal pathogens between supra- and subgingival plaques according to the kind of teeth. However, the incisors were at higher risk for harboring F. nucleatum (p <0.05). Conclusion: These results reveal that anaerobic periodontal pathogens can be detected in supragingival plaques. Supragingival plaque may function as a reservoir of peri-odotopathogens.