• 한국안전학회지
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• 제28권1호
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• pp.81-87
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• 2013

Crane operators usually work with their necks bent forward in a seating position for a long period. They have complained of their musculoskeletal stress at their necks. The objective of this study was to find the level of stress at the neck when crane operators bend their neck forward during their work. Experiments were conducted in the laboratory where subjects bent their necks forward for 1 minute and took a rest for 0.5 minute and repeated this performance for 60 minutes. Subjective evaluation using Borg's CR-10 scale and electromyography (EMG) were used to check the level of the stress at the neck. Subjects reported that the level of pain at the end of 60 min. experiment was close to the extreme pain(level 8.95). The EMG level(amplitude) increased 80% on the average and the center frequency of EMG shifted to the lower frequency level which indicated fatigue of neck muscles. Thus, it was found that there is quite much neck stress for crane operators when they maintain their neck posture of bending forward for a long time during their work. This information will be a basis in searching for an intervention measure for the crane operators' neck stress.

• 한국전기전자재료학회논문지
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• 제20권6호
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• pp.555-560
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• 2007

This paper describes the results of a study on the sealing integrity of polymer housed surge arrester based on the thermal mechanical test. The polymer housed surge arrester employs silicone insulating materials for its housing, instead of the conventional porcelain housing. The polymer housed surge arresters exhibited the highest sealing integrity because it is not air volume between the FRP(fiber reinforced plastics) module and the silicone housing. In accordance, the sealing integrity of station class surge arresters is investigated with moisture ingress test. And, the influence of sealing integrity was evaluated through such as measurement of the deflection, reference voltage, leakage current. In electrical characteristics, reference voltage decreased in the range of $16.45{\sim}16.15\;kV$ with after thermal mechanical test. In contrary, despite the continued moisture ingress, the polymer housed surge arresters exhibited almost the same leakage current value and the resistive leakage current has risen slightly. As a results, It was thought that the polymer housed surge arresters shows good stability with sealing integrity.

• 한국조경학회지
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• 제23권2호
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• pp.182-194
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• 1995

The major objective of this study was to develop recommendations for improving the design of pergola facilities located in neighborhood parks. The study employed the following methods : Physical measures and questionnaires. Physical treasures were taken of certain environmental attributes such as pergola sizes, structures, materials, etc. Questionnaires were randomly distributed to pergola users on the same day on which physical measures were scheduled. All data were collected in 1994 during the season of pergola use, September 3 to October 9. The major findings are as follows; 1. Of the 508 respondents to the question about use motivations, approximately 32% were a shady place, 18% seating arrangements suitable for conversation, 15% unconsciously, 13% a lack of bench in the park, 9% good view, and 13% other. 2. Regression analysis indicated that the best predictors of pergola user' satisfaction were : harmony with surroundings, accessibility, aesthetics of pergolas and benches, function of benches, and climbing plants. 3. Pergola design needs to be developed because pergola users were less satisfied with their pergola than with the park.

• 한국안전학회지
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• 제34권3호
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• pp.75-82
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• 2019

The purpose of this study was to evaluate the effectiveness of a vibration feedback system in improving two safe seating postures of office workers. In addition, the relative effectiveness of positive and negative feedback procedures was examined. Participants were four office workers. The dependent variables were the percentages of time participants spent in the safe sitting postures including shoulder, back, and overall body positions during the experimental sessions. A multiple-baseline design counterbalanced across participants was adopted. For two participants, the negative procedure was introduced first after baseline and positive procedure was introduced in the next phase. For the other two participants, the sequence of introducing the positive and negative feedback procedures was reversed. The result showed that the vibration feedback system, regardless of the type of the procedure, was effective in improving the safe sitting postures for all participants. However, the difference between the two procedures was not clearly shown. The benefits of the automated observation and vibration feedback system in workers' safety were discussed.

• 소성∙가공
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• 제31권5호
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• pp.261-266
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• 2022

To reduce the weight of the vehicle, the application of the high strength steel sheets to chassis parts is increased. High forming load is induced during the shearing process of steel chassis parts made of high strength steel, and the possibility of an eccentric load is increased depending on the product seating condition on the die, which decreases the stability and lifespan of the die. In this paper, a three-dimensional finite element analysis with the continuum element was conducted using the damage theory for the cam-trimming process of the front lower arm. The structural analysis of the trimming die was performed with the forming load result obtained from the analysis, and the amount of deflection and the stress distribution of the die during the shearing process were evaluated for the confirmation of the tool stability. The shape of the weak region of the die was modified according to structural analysis and then the stability was confirmed with the finite element analysis. The analysis result showed that the possibility of tool failure during cam-trimming process was remarkably reduced, and the reliability of the proposed modified design was validated.

• 한국과학교육학회지
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• 제29권3호
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• pp.291-303
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• 2009

According to social constructivism, group interaction is very important when students construct their knowledge. Many researchers have developed methods of teaching on the basis of group interaction because they recognized the importance of group interaction. There are a large variety of issues related to group interaction including group size, the gender and ability composition of groups, seating arrangements, textbook use, gestures, and role assignments. However, research on group interaction in science learning is still insufficient. In this study, we focused upon the emerging role of the primary leader. We investigated the primary leader's diverse role when students are solving mechanics problems. The participants were one group composed of three students in an upper-level mechanics class. To analyze these students' group interactions, their verbal interactions during meetings were videotaped and audiotaped during one-semester period. We also conducted interviews with the three students and analyzed their reports. As a result, we could find a special student who had the role of primary leader. We could also find the leader's three different leadership roles in different problem situations by inductively; explainer, facilitator and evaluator. Group interaction had different aspect according to the different role of leaders. The group interactions were the most active when the leader played the role of facilitator.

• 대한인간공학회지
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• 제33권4호
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• pp.255-265
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• 2014

Objective: The purpose of this study was to evaluate comfort levels of functional and non-functional chairs using subjective comfort rating, interface pressure measurement, muscle activity measurement, and skin temperature measurement. Background: Chairs are used for a prolonged period of time for sitting in many places such as the office, at university, at school, in industry, and so on. Almost all people use chairs in their everyday life. The functional properties of the chair are associated with comfort. Method: The subjective evaluation contains questions regarding chair comfort which can be rated with five point scale. The body-seat interface pressure was measured using a pressure mat system. The symmetry of sitting was measured using electromyography. The change in body part (thigh and buttock) temperature before and after sitting on a chair was measured with an infrared camera. Results: Participants rated significantly (p < 0.05) higher comfort scores for the functional chair in relation to the buttock and thigh region. Also, the participants felt a better cushion effect in the functional chair. When using the functional chair, lower interface pressure, better thermal comfort, and better symmetry of erector spinae muscle activity were observed. Conclusion: Overall, interface pressure measurement, muscle activity measurement, thermal imaging and subjective comfort score results showed that the functional chair was more comfortable than the non-functional chair. Application: The adopted methodologies could be used to measure the seating comfort of train seats.

• 한국식품조리과학회지
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• 제27권6호
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• pp.825-838
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• 2011

The main purposes of this study were to assess coffee shop use and to identify the influence of physical environment of a coffee chop on customer behavioral intention. The survey was administered from April to May 2011, targeting twenties college students in Seoul, Gyeonggi Province. A total of 174 copies of the questionnaire were collected for the data analyses such as frequency test, descriptive analysis, chi-square analysis, reliability test, factor analysis, ANOVA, Duncan's multiple range test and multiple regression analysis using SPSS 17.0 program. The main results of this study were as follows: The number of visits was once or twice a week. Students went with their friends to the coffee shop. Most of the students answered that they visit the coffee shop at any time. The main purpose of visit was to have time to relax. The main source in choosing a coffee shop was recommendation from others. The main criterion for the selection of the coffee shop was atmosphere. Americano was a favorite drink. Coffee was drunk with a cake. Expenditure per visit was 3,000~5,000 won. The choice of the coffee shop was selected by the student. The factor analysis identified seven underlying dimensions of coffee shop physical environment perceptions (seating comfort, attractiveness, cleanliness, harmony, ambient condition, congestion, amenity) and one dimension of customer behavioral intention. Through multiple regression analyses, four determinants (attractiveness, cleanliness, amenity, ambient condition) were found to have the greatest impact on customer behavioral intention.

• 건축역사연구
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• 제17권2호
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• pp.27-45
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• 2008

This study examines the details and characteristics of prizewinning plans of Cho-Sun housing plan competition promoted by Daily Cho-Sun Company during Japanese colonial period. The main features of Cho-Sun housing plan competition were that the competition held with an application of popular newspaper readers and a judging committee was composed of only Korean architects, especially Park, Gil-Ryong as the president of the board of examiners. Cho-Sun housing plan competition put ideological factors for the improvement of living as like advancing to the cultured(modem) life, respecting for family life, respecting for privacy of family members and so on. First of all, the competition suggested the direction of the improvement of dwelling spaces which focused on making harmonious home life. This study found common characteristics of prizewinning plans of Cho-Sun housing plan competition as the result. First, Cho-Sun housing plan competition introduced a centralized house plan as a model of the improvement of small-sized houses. Second, architectural orders of western or Japanese style mingled with ones of korean traditional style in prizewinning plans as entrance hall, western style reception room(parlour), maid's room, bathroom for example. And a manner of seating using chairs was brought into the style of living which would be assumed in the prizewinning plans. Third, traditional way of composing dwelling spaces was maintained, receiving the characteristics of dwelling spaces of japanese style simultaneously, which central corridor was put at the heart of house for improving arrangement of rooms and flow lines. Fourth, lavatory and bathroom were placed inside of the house.

• 대한임상전기생리학회지
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• 제6권1호
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• pp.69-79
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• 2008

In this paper, the effects of the external-rotation exercise on the gait of hemiplegia was investigated. 26 patients with hemiplegia due to cerebrovascular accident participated in this study. Subjects were randomly assigned to experimental group(n=12) and control one(n=14). 12 subjects of the experimental group were received the external rotation reducing exercise on the mat with seating and supine posture after the general therapeutic exercise for hemiplegia. 14 subjects of the control group were received only general therapeutic exercise. The effects of external rotation reducing exercise were evaluated by measurements of gait velocity, cadence, stride length, step length and foot angle using ink-foot prints. The collected data were analyzed statistically based on Wilcoxon, Mann-Whitney and correlation analysis. After treatment of three weeks, it turned out that external rotation reducing exercise has the significant effect on foot angle(p<0.01). However the exercise has no statistically significant direct effect on the gait velocity, cadence, stride length and step length.