• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.3
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• pp.326-333
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• 2015

This paper reports an adaptive positive feedback bias control technique for operational transconductance amplifiers to adjust the bias current based on the output current monitored by a current replica circuit. This technique enables operational transconductance amplifiers to quickly adapt their power consumption to various analog workloads when they are configured with negative feedback. To prove the concept, a test voltage follower is fabricated in $0.5-{\mu}m$ CMOS technology. Measurement result shows that the power consumption of the test voltage follower is approximately linearly proportional to the load capacitance, the signal frequency, and the signal amplitude for sinusoidal inputs as well as square pulses.

• Journal of the Korea Society of Computer and Information
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• v.24 no.6
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• pp.183-188
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• 2019

This study aimed to analyse the effects of self-control and impulsiveness of college students on smart phone addition and whether self-esteem has mediating effects on them. For the purposes, this study interviewed 4-year college students in Gwangju City with the use of a questionnaire and 314 copies of the responses were used for a final analysis. The data collected was analysed with the use of SPSS 22.0 and the results are presented as follows: First, behavior impulsiveness has a positive effect on self-esteem and smart phone addiction. Second, self-esteem had a positive effect on smart phone addiction. Third, it was discovered that behavior impulsiveness had a positive effect on smart phone addiction through an analysis of mediating effects while self-esteem had an indirect effect on it. Therefore, it was suggested that more care should be paid on smart phone addiction and development of programs against it should be facilitated.

• Research in Community and Public Health Nursing
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• v.23 no.2
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• pp.222-230
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• 2012

Purpose: This research is to understand the effects of senior simulation on employees of elderly care facilities and utilize it in their job training. Methods: This research is a nonequivalence control group pre-to-post quasiexperiment research. 18 employees who have experienced senior simulation are set as test group and 18 other employees who have not experienced senior simulation are set as control group. Results: The hypothesis that 'the test group which has experienced senior simulation will show a positive change in their attitude on elderly care, compared to the control group' and 'the test group which has experienced senior simulation will show a positive change in understanding of elders, compared to the control group' was supported. The hypothesis that 'the test group which has experienced senior simulation will show a positive change in job satisfaction and performance of duties, compared to the control group' was dismissed. Conclusion: The senior simulation seems to contribute to elderly care facilities employees' change in their viewpoints of elders and broaden their understanding of them. The senior simulation was meaningful to provide basic help with implementing job training programs.

• Journal of Environmental Health Sciences
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• v.35 no.5
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• pp.417-425
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• 2009

The purpose of this study was to investigate the whitening effect of Angelicae dahuricae Radix water extract (ADWE) by its application on artificial tanning spots which were induced by 1,500 $mJ/cm^2$ of UVB radiation on the backs of brown guinea pigs weighing approximately 450~500 g. Thirty ${\mu}l$ of ADWE, at each application, were applied twice a day, 5 days a week, for 8 weeks to the guinea pigs. The artificial tanning spots were divided into 3 groups which were vehicle control group [propylene glycol: ethanol: water (5:3:2)], positive control group (2% hydroquinone) and experimental group (2% ADWE). The visible whitening effect and changes in melanin index were evaluated once a week. On completion of the experiment, the animals were sacrificed under anesthetization, and the artificial tanning spots were excised by biopsy punch and stained with Hematoxylin and Eosin (H&E) to observe histological change and also stained with Fontana-Masson's silver (F-M) and S-100 to observe melanin pigmentation and melanocytes. In the gross observation, the experimental group showed higher pigmentation than the positive control group but lower pigmentation than the vehicle control group. Histological observation confirmed that ADWE had a positive whitening effect by showing a lower distribution of melanin and melanocytes in the epidermis of experimental group than in the vehicle control group.

• Korean Journal of Human Ecology
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• v.14 no.2
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• pp.269-276
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• 2005

The purpose of this study is to examine, according to sex and grade, the relationship and difference between mothers' parenting attitudes and self-perceived competences of their children. 197 children of the 4th through the 6th grade were selected from an elementary school in Daejeon area. We used the Perceived Competence Scale for Children (Harter, 1982) to measure their self-perceived competence and the Mother's Parenting Attitudes Scale (1990, Lee & Park) to measure parenting attitudes of their mothers. Major findings are as follows: First, there were significant differences in the children's self-perceived competence according to their perception of parental warmth and control. Children with more perception of parental warmth and consistent control considered themselves higher in cognitive and social competences and in self-worth. Boys perceived higher mother's consistent control and positive participation in parenting-attitudes than girls. Girls perceived themselves higher than boys in global self-worth. Next, Out of the three grades the 4th graders indicated more perception of attachment, authoritarian control, and positive participation in parenting attitudes. There was statistically no difference in self-perceived competences of children according to their grades. Finally, there were correlations between mothers' parenting attitudes and perceived competences of their children. Children with more perception of parental warmth, attachment, positive participation, and consistent control showed higher level of physical competence, social competence, and global self-worth.

• International Journal of Advanced Culture Technology
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• v.9 no.1
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• pp.79-88
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• 2021

This study was a cross-sectional descriptive investigative study to analyze the effects of sub-factors of cognitive emotional control on life goals. The subjects of the study were 184 people in their 20s, and they were collected online from December 2020 to January 5, 2021 using structured cognitive control capabilities and life goal questionnaires. The collected data were performed using SPSS 18.0 for Frequency, Independent Sample t-test, Pearson correction analysis, Simple regression analysis, and Multiple regression analysis. According to the study, men had both life-oriented and achievement-oriented life goals higher than women. Among the sub-factors of cognitive emotional control (positive focus change, positive reassessment, expansion of view, re-accept plan, acceptance, rumination, self-criticism, others criticism, and destruction) were male and female were higher in self-criticism. Factors affecting life-oriented life goals have been shown to be expanding views, re-accepting plans, and criticizing others, while positive re-evaluation negatively affects achievement-oriented life goals. Based on these results, life-oriented life-goals tend to exhibit adaptive responses to expand views and revise plans and maladaptive responses to blame others, while achievement-oriented life-goals have the ability to positively reassess situations, modify plans and accept negative reactions.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2319-2328
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• 2018

This paper introduces a control method for a transformerless MMC-HVDC system. The proposed method can effectively control the grid currents of the MMC-HVDC system under unbalanced grid conditions such as a single line-to-ground fault. The proposed method controls the currents of the positive sequence component and the negative sequence component without separating algorithms. Therefore, complicated calculations for extracting the positive sequence and the negative sequence component are not required. In addition, a control method to regulate a zero sequence component current under unbalanced grid conditions in the transformerless MMC-HVDC system is also proposed. The validity of the proposed method is verified through PSCAD/EMTDC simulation.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.614-622
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• 2010

This paper presents a control method, which reduces the pulsating torque and DC voltage problems of a doubly fed induction generator (DFIG)-based wind turbine system. To reduce the torque and power ripple, a current control scheme consisting of a proportional integral (PI) controller is presented in a positive synchronously rotating reference frame, which is capable of providing precise current control for a rotor-side converter with separated positive and negative components. The power theory can reduce the oscillation of the DC-link voltage in the grid-side converter. In this paper, the generator model is examined, and simulation results are obtained with a 3 kW DFIG-based wind turbine system to verify the proposed control strategy.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.4
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• pp.73-93
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• 2004

This study was to identify the determinants of web interactivity and investigate the structural relationships between web interactivity, e-brand relationship quality, and customer loyalty. For these purposes, the authors developed several hypotheses and collected the data from 268 users of Internet site. The data was analyzed with LISREL 8.5. The findings and summary are as follows. First. control had a significantly positive effect on satisfaction. Second, two-way communications had not an effect on satisfaction and trust. Third, responsiveness had a significantly positive effect on satisfaction and customer loyalty. Fourth, satisfaction had a significantly positive effect on trust and customer loyalty. Finally, trust had a significantly positive effect on customer loyalty. At the end of this paper, the managerial and theoretical implications, limitations and further research directions were suggested.

• The Korean Journal of Community Living Science
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• v.20 no.3
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• pp.331-341
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• 2009

The purpose of this study is to develop a nature friendly education program that would support ecological literacy of preschool children and to examine the effects of the program on their ecological knowledge and positive attitudes toward nature. The subjects of the study were 59 children from two child-care centers located at Gyeonggi Province. 30 preschoolers from one center were allocated into an experimental group, while 29 preschoolers from the other center were regarded as the control group. The program was composed of 24 sessions, performed three times a week for 20-30 minutes from May to June 2009. The instrument included the knowledge and attitudes toward the environmental scale for preschool children. The following results were obtained. First, the experimental group was found to attain higher level of ecological knowledge and more positive attitudes about nature as a result of the program. Second, after the program was administrated, the experimental group showed higher level of the knowledge and more positive attitudes about nature than the control group. These results suggest a program which conducts within a integrated teaching frame of meeting and getting familiar with nature and taking care of animals and plants, can become an effective early childhood education tool which fosters positive attitudes and knowledge concerning the environment.