• 한국자동차공학회논문집
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• 제7권7호
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• pp.221-228
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• 1999

A full-time four wheel drive vehicle is driven literally full time by the front and the rear wheels. Front and rear drive shafts are rotated rapidly in the extremely torsional state, which can cause various vibration and noise problems. The purpose of this study is to reduce the vibration and the noise of the full -time four wheel drive vehicle. In this paper, both the causes and the methods for reduction of torsional vibration are suggested. For this study, the characteristics of the torsional vibration are analyzed by free and forced torsional vibration simulation. And this paper described the influence upon the torsional vibration with emphasis shafting system. The validity of simulation models is checked by the field test. The forced vibration simulation with the variations of shaft design factors are performed by the checked models. According to the simulation , the resonance region shifts and the torque fluctuation varies in the system,. Finally, the methods and the effects for the torsional vibration reduction in driveline are proposed.

• 대한가정학회지
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• 제48권5호
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• pp.73-85
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• 2010

The purpose of this qualitative research is to explore the intergenerational ambivalence of mothers with preschoolers. Twenty full-time mothers and 19 working mothers were interviewed in depth. Most of the participants who received instrumental support from their mothers showed ambivalence, and especially the working mothers were more likely to feel ambivalence than the full-time mothers. However, participants who received little or no support from their mothers did not report any ambivalent feelings. Their ambivalent feelings came from both their social structure and intrapersonal contradictions. In order to avoid ambivalent feelings, some participants redefined receiving support from their mothers as a positive thing. Meanwhile, the participants who received active support tried to divert their ambivalence by providing child care support for their children, and they showed a 'repayment provision' tendency. Some working mothers and most of the full-time mothers said they would allot 'limited provision' by excluding child care support for their children. Those who were aware of this ambivalence issue sought 'reasonable provision' for their children. Depending on these results, several suggestions are presented to solve the ambivalence.

• 한국통신학회논문지
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• 제30권4A호
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• pp.282-287
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• 2005

송신다이버시티 시스템에 사용되는 시공간 블록부호(space time block code)는 송신안테나가 2개보다 많은 경우 최대 전송률과 최대 다이버시티 이득을 동시에 제공할 수 없다. 송신안테나가 4개인 경우 최대 전송률을 제공하면서 간섭을 최소화하는 준직교성 블록부호가 있다. 최근에는 준직교성에 의해 발생하는 블록부호의 간섭을 제거하는 단순상관제거 알고리즘이 제안되어 최대전송률과 최대 다이버시티 이득을 얻을 수 있게 되었다. 본 논문에서는 신호의 전송전력을 다르게 할당하고 수신단에서의 빼기 연산에 의한 간단한 간섭제거로 잡음 증가 없이 성능을 개선하는 복호화 과정을 제안한다.

• Journal of Power Electronics
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• 제16권2호
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• pp.425-435
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• 2016

This paper presents a comprehensive theoretical analysis and an accurate calculation method of the dead-time required to achieve zero-voltage-switching (ZVS) in a battery charger with the phase-shifted full-bridge (PSFB) topology. Compared to previous studies, this is the first time that the effects of nonlinear output filter inductance, varied Miller Plateau length, and blocking capacitors have been considered. It has been found that the output filter inductance and the Miller Plateau have a significant influence on the dead-time for ZVS when the load current varies a lot in battery charger applications. In addition, the blocking capacitor, which is widely used to prevent saturation, reduces the circulating current and consequently affects the setting of the dead-time. In consideration of these effects, accurate analytical equations of the dead-time range for ZVS are deduced. Experimental results from a 1.5kW PSFB battery charger prototype shows that, with the proposed analysis, an optimal dead-time can be selected to meet the specific requirements of a system while achieving ZVS over wide load range.

• 한국산학기술학회논문지
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• 제15권4호
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• pp.2363-2369
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• 2014

DVR 시스템은 다수의 카메라를 지원하고 채널당 30프레임의 영상을 실시간으로 받을 수 있어야 한다. 따라서 Full-HD급 Multiplexer와 별도의 하드웨어 압축 Codec을 사용하는데, 본 논문에서는 이들을 사용하지 않고 FPGA와 CPU가 가지고 있는 GPU를 이용하여 4채널 Full-HD급 PC기반 DVR의 설계 및 구현 방법에 대하여 기술한다. Multiplexer와 H/W Codec을 사용하지 않는 기존의 방법으로는 실시간으로 채널당 20프레임 정도의 영상을 획득하는 단점을 가지고 있다. FPGA를 이용하여 다채널의 영상을 실시간으로 획득하는 시스템을 설계하였으며, 소프트웨어로는 Intel Media SDK를 이용하여 영상 압축을 구현하였다. 구현된 제품의 성능 평가 결과, 제시한 요구 성능을 모두 만족하였고, 하드웨어 압축 코덱디바이스를 제거함으로써 시스템의 실용성을 확인 하였다.

• 아동학회지
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• 제13권2호
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• pp.217-228
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• 1992

The purpose of this study is to examine the effects of early full-time nonparental care during infancy/toddlerhood on children's socioemotional behaviors during the preschool period. Subjects for this study were 105 three- to five-year-olds from middle-class families in the U. S. A. Children were assigned to one of three groups according to their early care history. Children's social interactions with peers and caregivers during indoor free-play sessions in day care centers were observed for 20 minutes. The head teachers rated the children's social and emotional behaviors on two questionnaires. Mothers completed the Attachment Q-sort for attachment assessment for the preschoolers. In addition, mothers were asked to fill out a questionnaire on their parenting practices. Children who had received full-time nonparental care during infancy and/or toddlerhood were rated by their teachers as being more intellectually competent than children who did not receive full-time nonparental care during first three years of life. They were, however, rated by teachers and were observed by the researcher as being more aggressive than children with no full-time nonparental care. These children were observed to engage in less wandering/onlooking behaviors than children who had not had any full-time nonparental care. Children's attachment security scores and dependency scores did not differ as a function of early nonparental care histories. When the effects of early care patterns, sex of child, and current attachment security to mothers on aggressive behaviors of the preschoolers were examined by a hierarchical regression model, then any "pure" effects of nonparental care and of attachment security on child aggression were minimal after controlling for family background, child care center quality, and maternal childrearing practices. Strong buffering factors for the preschool children (family characteristics, parenting styles, and high quality nonparental care) mediated a possible risk factor of early nonparental care and promoted optimal outcomes for the children.

• 융합정보논문지
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• 제11권9호
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• pp.75-83
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• 2021

본 연구는 품질관리업무 전담자 제도 도입이 회계법인의 감사품질에 미치는 영향을 실증적으로 분석하였으며, 현재 시행 중인 상장회사 감사인 등록요건의 주요 내용인 품질관리제도 구축의 중요성을 확인하였다. 본 연구에서 감사품질은 선행연구를 따라 재량적 발생액을 이용하여 측정하였고, 품질관리 전담자가 존재하는 회계법인과 품질관리 전담자가 없는 회계법인의 감사품질과 품질관리 전담자 제도 도입 전후 즉, 2015 회계연도 이전과 2016 회계연도 이후의 감사품질을 비교하여 품질관리 전담자 제도가 회계법인의 감사품질에 유의한 영향을 미치는지를 분석하였다. 본 연구의 실증결과를 요약하면, 첫째, 품질관리 전담자가 존재하는 회계법인의 감사품질이 품질관리 전담자가 없는 회계법인의 감사품질보다 우수하다는 것을 확인하였다. 둘째, 품질관리 전담자 제도도입 후 회계연도의 감사품질이 도입 전 회계연도의 감사품질보다 우수하다는 것을 확인하였다.

• 가정과삶의질연구
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• 제14권4호
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• pp.145-162
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• 1996

The purpose of this study was to compare time use pattern of Korean working couples with those of Japanese counterparts. The data for240 Korean couples living in Seoul and 162 Japanese couples living in Tokyo were collected using structured questionnaire and time diary. The time use patterns of couples were analyzed according to employed status of wives. The results were as follows. The similar time use patterns were found between couples of two country. However the amount of time allocated for daily activities was found to be somewhat different. The amount of time spent by husbands on paid and house work was found to be different according to their wives employment status. The orean husbands of full-time employed wives and the Japanese husbands of part time employed wives spent the longest time on paid work. The Japanese husbands of full-time employed wives spent much more time on housework than those of Korean counterparts did. The social-cultural time of Korean couples was enerally longer than that of Japanese couples. The Korean couples spent more time on watching TV whereas the Japanese couples used more time doing family activities hobbies and moving for social-cultural activities.

• 한국환경보건학회지
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• 제39권1호
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• pp.71-82
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• 2013

Objectives: This study was performed in order to investigate hand hygiene practices among food-service businesses employees based on the awareness of hand-washing and load of indicator bacteria on their hands. It focused on the comparison of full-time and part-time workers in food-service workplaces. Methods: A direct-interview questionnaire survey and microbiological analysis were carried out with sixty workers each. Samples for microbiological analysis were collected through a modified glove-juice method from the hands of the food-service workers and were analyzed for aerobic plate count, total coliform, fecal coliform, Escherichia coli, Staphylococcus aureus, and Salmonella spp. Microbiological analysis was done according to the Food Code of Korea. Results: Significant differences (p<0.01) were found in the survey between the full-time and part-time workers in hand-washing frequency, use of hand-washing agents, and hand-drying methods. More full-time workers responded to washing their hands after preparing food, after visiting outside, after handling raw materials, and before putting on gloves/when changing gloves than did part-time workers (p<0.05). No remarkable difference was found in bacterial load on the hands except in the aerobic plate count between the two groups. The detection of E. coli, S. aureus, and Salmonella spp. on the hands of some food-service workers in both groups revealed poor hand hygiene practices. Conclusions: The results of this study indicate that there is a need for training programs in order to improve hand hygiene practices and strict hand hygiene compliance by food-service workers.

• 대한한의학회지
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• 제44권3호
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• pp.59-73
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• 2023

Objectives: The role of physician-scientists who bridge the gap between basic science and clinical medicine is crucial in advancing medical innovation. This study aims to examine the educational and research environment and career satisfaction of graduate students in Korean Medicine among those who are Korean medicine doctor (KMD). Methods: This study analyzed the results of a survey consisting of respondents' composition, job status, graduate education and job satisfaction, economic conditions, career determinants, and obstacles to the career path of KMD-scientists from 65 participants including both full-time and part-time graduate students. Results: The results revealed significant differences between full-time and part-time graduate students in terms of weekly hours spent and job priorities, motivation for entering graduate school, career preferences, and desired career paths. The study highlights the need for tailored support for full-time and part-time graduate students and the importance of economic assistance in fostering KM scientists. Economic difficulties were identified as a major obstacle for full-time graduate students pursuing research careers. Tuition fees were found to be a significant burden for all graduate students. Furthermore, it emphasizes the importance of enhancing the research capabilities of part-time graduate students and improving the quality of education to foster KMD-scientists. Conclusion: This research provides essential insights for Korean Medicine colleges and graduate schools to develop targeted improvement plans and effectively train KMD-scientist.