• Journal of Electrical Engineering and Technology
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• 제12권5호
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• pp.1891-1901
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• 2017

In this paper, optimal control of the fuel cell and design of a high-efficiency power converter is implemented to build a high-priced fuel cell system with minimum capacity. Conventional power converter devices use a non-isolated boost converter for high efficiency while the battery is charged, and reduce its conduction loss by using MOSFETs instead of diodes. However, the efficiency of the boost converter decreases, since overshoot occurs because there is a moment when the body diode of the MOSFET is conducted during the dead time and huge loss occurs when the dead time for the maximum-power-flowing state is used in the low-power-flowing state. The method proposed in this paper is to adjust the dead time of boost and rectifier switches by predicting the power flow to meet the maximum efficiency in every load condition. After analyzing parasite components, the stability and efficiency of the high-efficiency boost converter is improved by predictive compensation of the delay component of each part, and it is proven by simulation and experience. The variation in switching delay times of each switch of the full-bridge converter is compensated by falling time compensation, a control method of PWM, and it is also proven by simulation and experience.

• 대한가정학회지
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• 제40권1호
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• pp.37-51
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• 2002

The purpose of this study was to explore university students′ perceptions about the elderly before and after an introductory course for gerontology. Sixty-two male and female undergraduate students participated in the study as a part of the course requirement. Throughout the semester, theme students received a series of classroom lectures on gerontology, as well as participated in diverse activities to experience elderly lives. A survey was administered with the students at the beginning of the first day of class and at the end of the semester. By the end of the unit university students were more likely to have accurate conceptions of and positive attitudes toward aging and the aged. More specifically, they were more likely to (1) perceive "old" and "getting old" as a positive one, (2) seem older adults spend their time on active self-development and social activities, (3) view older adults are important, (4) change opinions about what an old person and young person do together, and (5) have a positive outlook on their own future lives as older adults.

• 한국실내디자인학회논문집
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• 제20권6호
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• pp.44-52
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• 2011

Louisiana Museum of Modern Art near Copenhagen is the most visited art museum in Denmark. It was originally founded by the director of the time, Knud W. Jensen and designed by two Danish architects, Vilhelm Wohlert and J${\o}$rgen Bo. The first part of the museum was built and opened to the public in 1958. The first part consisted of just a few exhibition spaces and glass corridors. But museum has been expanded step by step into a large park-like museum throughout 40 years of time. Louisiana museum has a unique environment in which art, architecture and nature are inter-related together. There was a very clear background for this museum atmosphere that was created by Knud W. Jensen from the very beginning. He wanted to make 'a sculptural park' or 'a low pavilion in the park'. The concept of 'park' was the key element. The architects, especially Vilhelm Wohlert who studied at the western area of the United States and influenced by the bay area architecture as well as the oriental wooden structure, interacted with the director's idea fully and made an invisible architecture in which 'Experience of Space' is the most important aspect. This thesis aims to analyze several crucial spaces of the museum and to find a hidden design characteristics. Chapter 2&3 explains general backgrounds and main design philosophy. Chapter 4 studies each parts' spatial experience and design methods with 3-dimensional diagrams. Chapter 5 tries to make an overall design characteristics that underlines the whole museum environment. The significance of Louisiana museum is not only in the fact that it is the most visited, but also in the fact that the role of architecture is to make a better environment where human and art are harmonized together within nature. The utopian idea of the founder started in doubt almost 50 years ago has been already successful in this small but vibrant park.

• 한국치위생학회지
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• 제11권5호
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• pp.695-706
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• 2011

Objectives : The purpose of this study is to assess oral health perception, oral health behavioral and family smoking status according to smoking experience in a part of high school students. Methods : A survey is conducted with a total of 648 first grader at high school in Dae-Gu city from 1st to 30th September, 2009. The results are as follows. Results : 1. 95.5% of respondents are 'smoking is very harmful for health' and the majority of smoking-related disease are lung cancer, oral disease, and oral cancer. 2. 127 respondents have experience in smoking and 62 respondents are smoking at that time. 59.7% respondents have 1 year smoking history and the majority of respondent are 5 cigarettes/day. 67.8% respondents are under 5 cigarettes/day. 3. In oral health behavioral by smoking, the majority of smokers' teeth brushing are 3 times, 47.2% and 2 times, 27.6%. The majority of nonsmoker's teeth brushing are 3 times, 47.0% and 2 times 26.5%. The results of teeth brushing time are significantly different between smokers and non-smokers(p<.001). The majority of smokers and non-smokers have not experienced about scaling. It is significantly different between 2 groups(p<.05). 4. The smoking rate of father and grandfather in smokers is higher than non-smokers. It is significantly different between 2 groups(p<.005). 5. The need for oral management in oral health education is gum treatment and dental caries treatment. 22.8% smokers and 25.7% non-smokers require to get gum treatment. 18.1% smokers and 20.2% non-smokers required to get dental caries treatment. Conclusions : Also Future longitudinal research is required to develop oral health promotion program contents according smoking-oral health.

• 한국가족관계학회지
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• 제22권3호
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• pp.73-101
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• 2017

Objectives: This study is to understand the experiences of overcoming pain of loss of family survivors in Suicide Bereavement Support Group(SBSG). Method: Experiential data was collected by in-depth interview(FGI, individual) to 10 family survivors(over 19) who having an experience participating in SBSG over 5months and analyzed using qualitative methodology. Results: We drew the result that 'SPACE model' which structuralize by 5 stages of suicide survivors' experience of SBSG of time path. SPACE model configured as follow: Stage1, Space in vacuum, the time to feel a sense of overwhelming feeling like pain, fear, alienation after loss of suicide, Stage2, Probing, when to find informations and resources to help survivors themselves, Stage3, Acclimation, having experiences empathy and healing as in SBSG, Stage4, Composure, accepting SBSG meaning as a part of their lives, loss of my family by suicide, and the beginning of bereavement, Stage5, Endurance, overcoming suffering through SBSG and try to help other survivors. Conclusions: SBSG is the opportunity for family survivors to overcome the pains from loss of suicide, shock, anger, grief, etc., and to empower them to help other suicide survivors.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.772-777
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• 2001

The gas-assisted injection molding process is often perceived to be unpredictable, because of the extreme sensitivity of the gas. Since a slight change in design or process parameters can significantly change the resulting gas penetration, few designers and molders have the level of experience with the new gas-assisted injection molding process required for the development of new parts. This paper is concerned with the unified molding for a thick cosmetic chest by using gas-assisted injection molding. CAE analysis was carried out to design the part and the gas channel without inducing sink marks. And based on the part weight measurement, the processing parameters to control gas penetration percentage were chosen through the method of design of experiments. A thick cosmetic chest was successfully produced using the gas assist technology. The sink mark issue associated with the conventional injection molded parts was resolved. Weight savings and cycle-time reduction were also achieved.

• 한국식생활문화학회지
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• 제9권2호
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• pp.159-170
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• 1994

Central commissary school foodservice operations' practices and their dietitians' job duties were assessed and compared with those of their counterpart of conventional school foodservice operations to find out strategies for early settlement and better management for commissary system. Survey qestionnaires consisted of general background, employees' work schedule and dietitians' job duties. 12 commissary schools(out of 22 existing in Korea) and 77 conventional schools from Kyungkido were participated in the survey. The results of this study can be summarized as follows: 1. Central commissary school foodservice was presently utilized at 5 schools from islands type, 11 schools from rural type, and 6 schools from urban type, consisting total of 22 commissary schools, and 52 satellite schools. 2. Dietitians were evenly employed with their experiences, 55.5% were those with less than 2 years of experience, 44.6% were those with more than 2 years of experience. 3. Commissary schools employed more full-time empolyees$(1.8{\pm}0.7)$ than conventional schools$(0.3{\pm}0.5)$, however as far as the production capacity was concerned, only the part-time employees played significant roles(p<.01). Regardless of the number of students, an absolute number of full-time employees were employed, and their duties were not carried out efficiently. The part-time employees of commissary schools performed more loaded work compared to their counterparts in conventional schools. 4. Out of the dietitians' foodservice duties, 'basic food service production$(3.9{\pm}0.7)$' were carried out adequately, whereas 'nutrition education and advertisement$(2.5{\pm}0.6)$' and 'administrative affairs and information related duties$(2.8{\pm}0.9)$' were not. In order to enhance their working capacity, systematic organizational reforms are imminent. 5. Survey results also showed that dietitians performed less duties at satellite school than at the central commissary. This indicates more systematic foodservice management practices are urgently needed.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 추계학술대회
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• pp.265-270
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• 2003

When designing an engine part the designer has to choose the proper material and to define the dimensions of the part. in the most rudimentary case he has available as guidelines the collective experience from similar applications. The performance of the part is tested on occasion of the trial runs for the full system, and possibly occurring deficiencies are corrected until a satisfactory usable life and safety of operation is achieved. This procedure is time consuming and costly, and the learning effect is minimal. These requirements have to be condensed into characteristic values ameanable to computation. Since testing and computation are complementary we have to look at the currently existing mathematical models for engine bearing performance.

• 초등상담연구
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• 제5권1호
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• pp.93-118
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• 2006

The aim of this research is to find out the common emotional factors that elementary school teachers feel when they experience in teaching children with ADHD and to know their responding process through experiential analysis. Seven elementary school teachers took part in this research as co-investigators, and I led the experiential approach. The co-investigators have analyzed their emotional experiences during 4 sessions. They learnt about the method of experience analysis and discussed their emotional experiences of children with ADHD. And they found out some factors concerning their emotional experiences and had the time to discuss in odor to search for the common factors of that process. Finally the co-investigators took part in a session to examine the factors which they have all agreed in, and then I verified this result. 1 interpreted the factors found and constructed a psychological resolution process. Two main objectives and the results of this research are as follows. First, are there any common factors among teachers who experience in treating children with ADHD? This research showed that elementary school teachers get angry and irritated with ADHD children's troubles. Second, what kind of psychological process is there in teachers' experiences children with ADHD? The psychological process of teachers dealing children with ADHD could be conceptualized in 5 steps, the step of recognizing an action of children with ADHD, the step of first cognitive consideration, the step of giving meaning and cognitive appraisal, the step of experiencing emotion, and the step of dealing with emotion. Teachers seemed to experience a little bit different psychological process. According to whether they thought about children's behavior positively or negatively in the second step, they had different emotional experiences. If they had a positive thought, they could take children's nonadaptive behaviors as personal characteristics. However, if they took them negatively, they considered them impolite and disobedient. Even when the teachers experienced negative emotions, their responses were divided into two groups whether they took it positively or negatively. This research showed that if teachers could control their negative emotional experiences, they could calm down with children with ADHD and treat them positively.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.269-276
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• 2011

This paper considers the rail crane scheduling problem with minimizing the sum of the range of order completion time and make-span of rail crane simultaneously. The range of order completion time implies the difference between the maximum of completion time and minimum of start time. Make-span refers to the time when all the tasks are completed. At a rail terminal, logistics companies wish to concentrate on their task of loading and unloading container on/from rail freight train at a time in order to increase the efficiency of their equipment such as reach stacker. In other words, they want to reduce the range of their order completion time. As a part of efforts to meet the needs, the crane schedule is rearranged based on worker's experience. We formulate the problem as a mixed integer program. To validate the effectiveness of the model, computational experiments were conducted using a set of data randomly generated.