• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.2
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• pp.109-117
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• 2009

In this study, thermodynamic performance of R430A is examined both numerically and experimentally in an effort to replace HFC134a used in the refrigeration system of domestic water purifiers. Even though HFC134a is used predominantly in such a system these days, it needs to be phased out in the near future in Europe and most of the developed countries due to its high global warming potential. To solve this problem, cycle simulation and experimental measurements are carried out with a new refrigerant mixture of 76%R152a124% R600a using actual domestic water purifiers. This mixture is numbered and listed as R430A by ASHRAE recently. Test results show that the system performance with R430A is greatly influenced by the amount of charge due to the small internal volume of the refrigeration system of the domestic water purifiers. With the optimum amount of charge of 21 to 22 grams, about 50% of HFC134a, the energy consumption of R430A is 13.4% lower than that of HFC 134a. The compressor dome and discharge temperatures and condenser center temperature of R430A are very similar to those of HFC134a at the optimum charge. Overall, R430A, a new long term environmentally safe refrigerant, is a good alternative for HFC134a requiring little change in the refrigeration system of the domestic water purifiers.

• Journal of Families and Better Life
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• v.34 no.5
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• pp.35-52
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• 2016

The purpose of this study was to compare college students' emoticon use for positive behavior and to analyze the impact of the factors. This study is consisted of 66 questions based on Social demographic characteristics, personality characteristics factors and both scales of emotional expression. The operational test was administered to 340 college students. In an effort to calibrate emoticon use of positive behavior, the results displayed significance differences depending on the gender and grade of the students. Women used more emoticons than men, and freshman used more emoticons than any other year of students. Women used more emoticons such as texts, images, and flash more than men. Students in their freshman year were shown to use more emoticons than students in other grade levels. Emotional expression was strongly related man with personality traits of integrity. Personality traits of sensitivity, openness, intimacy, and sincerity had a significant influence on the emotional expression. An emoticon is, therefore, be a useful tool to express their emotions. Male and female students with higher levels of congeniality had expressed more emotions that were self-defence ambivalent and concerned-relation ambivalent. However, in the case of the female students, those with higher levels of self-defence ambivalent emotional expressiveness had a lower usage of positive emoticons, while male students with higher levels of self-defence emotional expressiveness used more positive emoticons. Higher levels of congeniality among groups that use mobile emoticons with their parents, whether the frequency of use was high or low, were associated with higher levels of self-defence ambivalence and concerned-relation ambivalence. Those with higher levels of sincerity had low levels of self-defence ambivalence and concerned-relation ambivalence, and those with higher levels of concerned-relation ambivalence had higher levels of positive emoticon usage.

• Journal of Korean Public Health Nursing
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• v.26 no.1
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• pp.5-15
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• 2012

Purpose: The effects of the organizational culture and health promotion life style on job satisfaction of nurses in general hospitals have been studied in an effort to provide basic information that will be helpful in effective management of the organization and enhancement of nursing. Method: The 341 samples used in the study were selected randomly from general hospitals having more than 250 beds in Gwangju province and Yosu province. Data collected were analyzed for frequency, percentage, ANOVA, t-test, Pearson's correlation analysis, and Multiple regression analysis using SPSS, a program package for statistical analysis. Result: Factors affecting job satisfaction included work years, position, monthly income, stress management, which is a substructure of health promotion life style, innovation-oriented culture, relation-oriented culture, and task-oriented culture in organizational culture. Results showed an influence of 64.2%. Ed - highlight: Please review. Conclusion: The organizational culture, such as an innovation-oriented culture, relation-oriented culture, or task-oriented culture, has a positive influence on job satisfaction.

• Magazine of the Korea Concrete Institute
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• v.8 no.5
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• pp.163-170
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• 1996

Cellulose fibers, being fairly strong and stiff as well as cheap and plentiful with low energy demand during manufacture, are strong contenders for the reinforcement of cement-based materials. Cellulose fiber-cement composites, generally manufactured by slurry-dewatering procedure, can find applications in the production of flat and corrugated cement sheets and many other thin-sheet cement products. This paper presents the results of an experimental study concerned with the effects of fiber content and moisture conditions on the flexural performance of these composites. An effort was also made to study the effect of pozzolanic admixtures on the flexural performance in different moisture conditions. The test results obtained were analyzed statistically using the analysis of variance in order to derive reliable conclusions. The results generated in this study were indicative of significant effects of fiber content and moisture condition of flexural performance. There is a tendency in flexural strength to increase in increase in fiber content up to 8%: flexural toughness values continue to increase even at higher fiber contents. Moisture content has a significant effect on the flexural performance. There is a tendency in flexural strength to decrease and flexural toughness to increase with increasing moisture content Composites incorporating pozzolans showed an increase in the flexural strength while slightly reducing the flexural toughness and were sensitive to variations in moisture content.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.11
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• pp.1221-1226
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• 2014

In an effort to improve the efficiency of the speech recognition, we investigate the effect of the number of phoneme clusters. For this purpose, codebooks of varied number of phoneme clusters are prepared by modified k-means clustering algorithm. The subsequent processing is fuzzy vector quantization (FVQ) and hidden Markov model (HMM) for speech recognition test. The result shows that there are two distinct regimes. For large number of phoneme clusters, the recognition performance is roughly independent of it. For small number of phoneme clusters, however, the recognition error rate increases nonlinearly as it is decreased. From numerical calculation, it is found that this nonlinear regime might be modeled by a power law function. The result also shows that about 166 phoneme clusters would be the optimal number for recognition of 300 isolated words. This amounts to roughly 3 variations per phoneme.

• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.991-996
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• 2014

Power frequency magnetic field is still a critical problem for new construction of overhead power transmission lines in Korea because most people have been concerned about possibly carcinogenic effects of it. Although reference level of power frequency(60Hz) magnetic field has been set to 200uT in ICNIRP guidelines published in 2010, Korean government has no intention of adjusting 83.3uT specified by law in 2006 to this new reference level in consideration of people's concerns for the time being. Regardless of the current regulated magnetic field value, electric utility company has been trying to reduce magnetic field in the residential area in the vicinity of overhead power transmission lines to take into account of public concerns on the long-term effect of magnetic fields. In an effort to reduce magnetic field, engineering side has made considerable efforts to develop passive loop based, cost-effective mitigation technique of power frequency magnetic field more than ten years. In order to verify developed power frequency magnetic field mitigation technique based on passive loop, a horizontal type of passive loop was designed and installed for commercially operating 154kV overhead power transmission line for the first time in Korea. The measurement results before and after the installation of passive loop showed that magnetic field could be reduced to about 20%. The electrical environmental effects such as AN, RI and TVI were assessed before and after the installation of passive loop and these values were complied with the requirements specified by electric utility. It has been confirmed from the field test results that passive loop could be commercially and cost-effectively utilized to mitigate power frequency magnetic field.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.820-828
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• 2018

The growing nuclear threat has amplified the need for developing diverse and accurate nuclear forensics analysis techniques to strengthen nuclear security measures. The work presented here is part of a research effort focused on developing a methodology for reactor-type discrimination of weapons-grade plutonium. To verify the developed methodology, natural $UO_2$ fuel samples were irradiated in a thermal neutron spectrum at the University of Missouri Research Reactor (MURR) and produced approximately $20{\mu}g$ of weapons-grade plutonium test material. Radiation transport simulations of common thermal reactor types that can produce weapons-grade plutonium were performed, and the results are presented here. These simulations were needed to verify whether the plutonium produced in the natural $UO_2$ fuel samples during the experimental irradiation at MURR was a suitable representative to plutonium produced in common thermal reactor types. Also presented are comparisons of fission product and plutonium concentrations obtained from computational simulations of the experimental irradiation at MURR to the nondestructive and destructive measurements of the irradiated natural $UO_2$ fuel samples. Gamma spectroscopy measurements of radioactive fission products were mostly within 10%, mass spectroscopy measurements of the total plutonium mass were within 4%, and mass spectroscopy measurements of stable fission products were mostly within 5%.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.6
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• pp.2901-2907
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• 2016

Background: Despite increasing debate about overdiagnosis and overtreatment of thyroid cancer in Korea, information to guide decisions on whether or not to undergo screening for and treatment of abnormal lesions of the thyroid is lacking. Moreover, studies have yet to outline what lay people know and want to know about thyroid cancer. The primary aim of this study was to explore general awareness of thyroid cancer among Korean women, their sources of information, and their satisfaction with the information they are provided. The secondary aim was to investigate information needs about thyroid cancer. Materials and Methods: A qualitative study using focus group interviews was conducted. Twenty-nine women were divided into four groups: (1) participants who had never undergone thyroid ultrasound screening; (2) those who had undergone screening, (3) those who continued to undergo regular check-ups with ultrasonography for benign nodules of the thyroid; and (4) participants who had undergone surgery for thyroid cancer. Results: A widespread lack of awareness of information on thyroid cancer was noted among participants in groups 1 and 2 who were not well aware of thyroid cancer and generally recognized it as a 'good cancer'. Surprisingly, instead of doctors and medical personnel, most participants reported obtaining information from acquaintances and media outlets. Moreover, most participants described dissatisfaction with their experience with screening and a lack of explanation on treatment and test results from medical personnel. Conclusions: Women in Korea seek reliable information on thyroid cancer that could help them to better understand the disease and make informed decisions regarding screening and treatment. More effort is needed from medical personnel to communicate the implications of thyroid cancer, screening results, and treatments thereof to lay people.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.3
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• pp.307-316
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• 2011

The majority of maritime accidents happened by human factor. For that reason, navigation experts want to an intelligent support system for navigation safety, without officer involvement. The expert system which is one of artificial intelligence skills for navigation support is an important tool that a machine can substitute for an expert through the design of a knowledge base and inference engine using the experience or knowledge of an expert. Further, in the real world, a complex situation requires synthetic estimation with the input of experts in various fields for the correct estimation of the situation, not any one expert. In particular, synthetic estimation is more important for navigation situations than in other cases, because of diverse potential threats. This paper presents the method of knowledge fusion pertaining to navigation safety knowledge from various expert systems, using a blackboard system. Then we will show the validity of the method via a design and implementation of test system effort.

• Korean Medical Education Review
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• v.9 no.2
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• pp.1-12
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• 2007

Purpose: The aim of this study is to identify the elements of success in curriculum reformation using focus group interview and faculty survey. Methods: We analyzed the 105 questionnaires that were collected horn 450 faculties in Yonsei University College of Medicine from September 1 to September 12, 2005. The interview of focus group was conducted to 105 faculty and students using 10 interview questions from July 25 to August 29, 2005. The data of focus group interview and faculty survey were analyzed by content analysis. frequency and percentile. Results : 66.7% of faculty have pointed out that it is right a direction of new curriculum but there are some problems in curriculum management. The most frequently addressed problem in the new curriculum is as follows : ability of self-directed learning(15.3%). deficiency of faculty understanding(10.5%). The faculty comments on the improvement areas of new curriculum such as curriculum revision (8.6%). efficiency of curriculum management (6.7%), reward and incentive system of education(6.7%). The focus groups pointed out the important factors of curriculum reformation such as horizontal and vertical integrity between subjects, improvement of student achievement test, enhancement of self-directed learning. responsibility and authorities of course director. Conclusions : It should be concluded. to succeed curriculum reformation, which the purpose of curriculum reformation announces obviously and management group should effort continuously so that professors may understand the new curriculum. The course directors have to responsibility and authorities operating the subjects and the university should develop the students' evaluation system and faculty performance appraisal system.