• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.3
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• pp.341-351
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• 1996

The values for the average and rms currents in a three-level PWM inverter are required in order to select the various components such as power semiconductor devices, capacitors and reactors of inverter circuit. And those are very useful for the designing of the heat sink. In this paper, therefore, the simple current equations are proposed for a three-level PWM inverter. Analysis of inverter current waveforms indicate that the average and rms inverter currents are dependent on the load power factor and PWM modulation index (Ma). Error analysis and experiment results verify the effectiveness of the proposed current equations. (author). refs., figs., tabs.

• Research in Community and Public Health Nursing
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• v.20 no.1
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• pp.49-58
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• 2009

Purpose: Purpose: The purpose of this study was to explore the yangsaeng level in a health management way of an aged women in rural area, and to offer basic material for the development of community's public health service. Methods: The subjects were 144 aged women who participated voluntarily in the questionnaire. The data were collected from January to February, 2008 with a self-administered questionnaire. Data were analyzed by SPSS 13.0 win program for finding frequency, percentage, mean, standard deviation, ANOVA and Tukey. Results: The average age of workers was 72. Total yangsaeng level was $3.08{\pm}.33$, highest yangsaeng factor was Activity & Rest Yangsaeng of $3.55{\pm}.46$ and lowest yangsaeng factor was Season Yangsaeng of $2.43{\pm}.75$. The total Yangsaeng level was the significant difference in monthly incomes(F=4.046, p=.047). Conclusion: Considering the results above, the yangsaeng level of aged women is affected by the age, education level, a monthly income etc. Therefore, for health promotion plan of aged women, consider that their age, educational level, economic level ect, and systematic education for promotion of health is necessary.

• Journal of Digital Convergence
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• v.16 no.5
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• pp.105-113
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• 2018

The purpose of this study was to find out the effects of the hotel using experience on customers' purchase and behavior intention. For this study, a total of 306 questionnaires among collected data for customers who hotel using experience at five star hotels located in Seoul from April 1, 2015 to April 30, 2015 was to ensure a valid sample. As a result of the experiments which conducted by factor analysis and regression analysis, it shows 1% level positive significant effects in purchase and continual purchase intention of "emotional experiencer", "physical experience factor", "continuous experience factor", and "superior experience factor", but it is 10% level significant effects in continual purchase intention positively effected continual purchase intention of "physical experience factor". Also, it shows 1% level positive significant effects on hotel customers' intention of reused, intention of suggestion, intention of recommendation of "emotional experiencer", "physical experience factor", "continuous experience factor", and "superior experience factor". From the study, it is expected to build hotel-customer relationship and brand level of awareness for activating customers' loyalty.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.110-115
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• 2004

Examine merits and demerits and obstacle factor that exist to all direction of digital infratechnology that is supplied on industry whole according to development special quality of computer by development of computer and Information Technology and electricity electron information communication facility that basic impulse insulation level does not exist examined scorched earth or an interference problem factor and countermeasure of semiconductor degauss of factor and electricity electron information transmission system that is numbed or causes system down.

• Journal of the Korean Society of Safety
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• v.29 no.5
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• pp.146-153
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• 2014

This study looks at the impact of psychological and physical factors of the working conditions on the health of workers depending on whether technology is used by such workers. The data used for the study is the third work environment survey. Out of 50,032 respondents, a total of 29,711 paid workers were used as analysis subjects. Although it was anticipated that the use of technology was a factor that hindered job autonomy and teamwork autonomy. However, the analysis results showed low levels of job autonomy and teamwork autonomy in the group that did not use technology. The study assumes a regression analysis model about work environment and work organizational practices of workspaces that have an impact on musculoskeletal complaints, stress symptoms and level of work satisfaction by controlling the social demographic variable that represents the level of individual sensitivity. As a result of the study, ergonomic risk had a significant effect on both groups that did or did not use technology with respect to stress symptoms, musculoskeletal complaints and level of work satisfaction. In particular, as workspace practices and work environment had an effect on the development of musculoskeletal complaints in the group that used machines, there is a need to improve such situation. The autonomous team work or level of job autonomy within the group that used technology may act as a risk factor to the health and welfare of workers. However, because it may also act as a buffer factor, there is a need for a change to reduce stress symptoms and increase the level of work satisfaction by improving autonomous team work and the level of job autonomy.

• Journal of environmental and Sanitary engineering
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• v.22 no.1 s.63
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• pp.67-74
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• 2007

The purpose of this study is to provide the necessarily basic data of the ideal growth of the students by investigating the effect of the student's stress due to the parent's achievement pressure. The sample of this study are In students consisting of 51 boys and 49 girls in the 3rd grade classes of "J" middle school located in Siheung city, Kyungki-do. The observed materials are used to investigate the parent's achievement pressure and the level of stress. Based on the observed data, the frequency, correlation, and t-test have been gained. The results are summarized as follows : 1. The perception of the parent's achievement pressure is shown more by the boy's achievement pressure($44.2{\pm}9.9$) than the girl's achievement pressure($39.939{\pm}11.089$), among the high level students. 2. The perception of the parent's achievement pressure is shown more the high($43.0{\pm}10.7$) and middle($42.9{\pm}11.8$) level students than the low($39.7{\pm}8.00$) level students. 3. The stress of male students was high in the Solving Problem stress factor with by the mean of $15.1{\pm}3.7$, and the stress of female students was high in the Self-Control stress factor with the mean of $13.3{\pm}3.9$. 4. The stress of high, middle, low level student was high in the Solution of Matter stress factor with the mean of $14.2{\pm}3.9$. 5. The results were the main cause of the stress than the parent's achievement pressure.

• Korean Journal of Social Welfare
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• v.66 no.4
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• pp.77-100
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• 2014

To validate the effects of students' individual factor, school organizational factor, and teacher factor on violent behavior toward peers in school, this study applied Hierarchical Linear Modeling and analyzed it using the HLM 7 program. To this end, it used survey data of students from 50 middle schools in Seoul and Gyeonggi province. A total of 1,777 cases from 50 middle schools were used for individual student-level analysis (Level 1), and used for school-level analysis (Level-2). According to the results of the analysis, student-level variables such as attitude toward violence, experience of child abuse at home, and delinquent peers had significant effects on school violence. The effects of violent discipline by teacher, which are used as a school-level variable, was statistically significant. Based on the result of the study, action plans and policies to resolve school violence were discussed.

• Korean Journal of Biological Psychiatry
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• v.13 no.1
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• pp.32-37
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• 2006

Background : Several studies have suggested that alterations of cytokine level could be related to the pathophysiology of bipolar disorder. In this study, we measured plasma level of Interleukin-12(IL-12), a pro-inflammatory cytokine and transforming growth factor-${\beta}$1(TGF-${\beta}$1), an anti-inflammatory cytokine before and after treatment in acute manic patients. Methods : The plasma concentrations of IL-12 and TGF-${\beta}$1 were measured using quantitative ELISA in 18 bipolar disorder patients and 25 normal controls at admission and 6 weeks later. The psychopathology was measured by Brief Psychiatric Rating Scale(BPRS) and Young Mania Rating Scale(YMRS). Results : IL-12 levels were significantly higher in bipolar manic patients than in controls before treatment. Following the 6-week treatment, the IL-12 level was decreased than before treatment, but sustained still higher level than normal control. TGF-${\beta}$1 level was not significant different between manic patients and normal controls before treatment, but was increased after treatment comparing with before treatment in bipolar patients. The ratio of IL-12 and TGF-${\beta}$1 was significantly decreased after treatment. Conclusion : Cytokine abnormalities in bipolar disorder might be involved in the pathophysiology of the illness. It is possible that TGF-${\beta}$1 plays an important role in the regulation of immunological imbalance in bipolar disorder.

• Korean Journal of Biological Psychiatry
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• v.14 no.3
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• pp.161-166
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• 2007

Objectives:Recent studies have raised the possibility that nerve growth factor(NGF) is abnormally regulated in the central nervous system(CNS) of animal models with alcohol dependence. The possible alteration of NGF by prolonged alcohol intake may play an important role in alcohol-induced neurotoxicity. Carbohydrate-deficient transferrin(CDT) is regarded as a reliable biological marker of alcohol dependence. The goal of this study was to estimate the changes of %CDT and serum NGF level according to the duration of alcohol abstinence, and to identify whether %CDT level is associated with the serum NGF level in the patients with alcohol dependence. Methods:The subjects were 24 patients with alcohol dependence. We used the Axis-Shield ASA to measure the %CDT level and the enzyme-linked immunosorbent assay(ELISA) to measure the serum NGF level. %CDT and NGF levels were measured immediately after the admission and at 2 weeks after the admission. Results:Decreased %CDT were observed during the period of 2 weeks after the admission. NGF level was not significantly different after 2 weeks. The NGF levels were not correlated with %CDT. The possibility of %CDT as a predictor of alcohol-induced neurotoxicity was not confirmed. Conclusion:Serum NGF levels is not a reliable indicator of abstinence state in the patients with alcohol dependence. Further studies are needed to evaluate the relation between two indicators in regard to hematological and neurological changes in alcohol dependence.

• Journal of The Korean Association of Information Education
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• v.23 no.1
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• pp.65-72
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• 2019

As the importance of SW education grows, researches are actively being conducted to improve students' thinking skills. We conducted the group III tasks, which are experiencing and challenging in Beaver Challenge 2018, on 55 students of 5th grade in elementary school. Based on the result, we analyzed their average scores and defined whether each test has a correlation with possession of smartphone, computer familiarity, patience, concentration, and academic ability. The result indicated challenging task boosted the average score, the percentage of correct answers, and the percentage of correct answers for each level of difficulty. Moreover, the challenge task scores were higher as they higher computer familiarity, patience and concentration level. However, possession of smartphones and academic ability did not affect the score. Lastly, the scores were affected by different factors in different level of difficulty that patience factor in advanced level, computer familiarity factor in intermediate level, and concentration factor in beginner level. Thus, further researches are necessary to be conducted to expand the scope of the analysis through the diversification of test subject group and expansion of an evaluation area.