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100 kWh급 초전도 베어링의 지름방향 준정적 특성 (Quasi-static Characteristics in Radial Direction of 100 kWh Class Superconductor Bearing)

  • 정세용;박병준;한영희;박병철;이정필;한상철
    • Progress in Superconductivity
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    • 제12권1호
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    • pp.27-31
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    • 2010
  • A superconductor flywheel energy storage system (SFES) is an electro-mechanical battery which transforms electrical energy into mechanical energy for storage, and vice versa. Many aspects of the quasi-static behavior of flywheel rotors still need to be studied closely, and the rotors require a stable and highly efficient supporting system such as high temperature superconductor (HTS) bearings, which offer dynamic stability without the use of active control. Quasi-static properties of HTS bearings in the radial direction provide data to solve problems which may occur in a running system. Since stiffness in countering rotor vibration is the main parameter for designing an HTS bearing system, we investigated the quasi-static properties of the magnetic force between permanent magnets(PMs) and HTS bulks in the radial direction. We measured radial stiffness, and discovered that bearing stiffness varied greatly depending on the number of active HTS bulks. This is valuable data for predicting the change in stiffness during partial HTS bearing failure. The quasi-static test results are used for optimal design and performance prediction for the 100 kWh class superconductor bearing.

관동맥 우회술의 수술성적-수술전 처치 및 수술수기의 영향에 관한 연구 (Surgical Result of Coronary Artery Bypass Grafting - The Effect of Pre and Intraoperative Procedures)

  • 김영태;홍종면;채헌
    • Journal of Chest Surgery
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    • 제26권2호
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    • pp.141-147
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    • 1993
  • A total of 40 patients having a diagnosis of atherosclerotic coronary arterial disease were analysed on the operative outcomes according to variables as follows: 1) preoperative risk factors such as age, sex, CCS (Canadian Cardiovascular Society) functional class, type of angina, number of diseased vessel, presence of left main coronary artery stenosis, previous history of habitual smoking and presence of other medical diseases (diabetes mellitus, essential hypertension), 2) preoperative management such as intravenous infusion of nitroglycerine, preoperative IABP (intra-aortic balloon pump) support and whether the operation was scheduled as emergency or not, 3) intraoperative variables such as infusion method and composition of cardioplegic solutions, number of distal anastomosis, use of internal mammary artery, total cardiopulmonary bypass time and total cross clamp time. Complications included operative death in 12.5%, perioperative myocardial infarction in 25.0% and perioperative arrhythmia in 17.5%. Nineteen perioperative variables were analyzed to identify risk factors for these end points. For operative death, presence of left main coronary artery stenosis (p = 0.056) and cardiopulmonary bypass time (p = 0.029) were significant in the univariate analysis, but presence of left main coronary artery lesion (p = 0.011, $\chi$$^2$= 6.45) and abscence of preoperative of IABP support (p = 0.069, $\chi$$^2$ = 3.30) were independent predictor in multivariate analysis (stepwise linear logistic regression).

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간호학생의 학업성취에 관한 연구 -대학 간호학생의 심리적 제특성과 학업성취와의 관계- (Study on Achievement of Nursing Students-Relationship between Psychological Test Characteristics and Academic Achievement of Nursing Students in a Baccalaureate Program-)

  • 이은옥;이미라
    • 대한간호학회지
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    • 제3권1호
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    • pp.53-66
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    • 1972
  • There is an urgent need to improve the tool predicting success or failure of academic achievement of nursing in Korea so as to identify as early as possible those students who should receive special instruction and to improve screening procedures for admission of nursing. The main purpose of this study is to identify the correlation between the grade point averages of courses learned and their psychological test characteristics in a baccalaureate nursing program. All 240 students, except freshmen, enrolled in Nursing Department of Seoul National University in the spring semester, 1972, participated in this study. All of the subjects completed the psychometric tests such as interest test, personality test and test of self-concept. Total grade point averages, grade point averages of general education subjects, of supporting science courses and of professional education subjects were used as performance criteria of the students. Through the calculation of product-moment correlation coefficients between the test scores and four grade point averages of each class and of total subjects, the following findings and recommendations were obtained. 1. There was so much variation in characteristics of interest test correlated with academic achievement of nursing students in each class. 2. Since the school objectives, curriculum and teaching strategies may affect predictive efficiency of characteristics of students'interest test, interest test must-be utilized in a homogeneous group in order to predict school achievement. 3. Characteristics of interest test positively correlated at significant level with total grade point averages of all subjects were scientific interest-biological, scientific interest-physical, and humanitarian interest. Scientific interest-physics: was the only characteristic positively correlated at significant level with total grade point averages and grade point averages of professional courses. 4. There were various patterns in characteristics of personality test correlated with school achievement of nursing students by class pattern and personality maturation as they progress toward higher classes. 5. A characteristic of personality test, responsibility, is in high positive correlation with academic achievement in the upper division of classes. 6. Responsibility was the sole personality factor positively correlated at significant level with total grade point averages and grade point averages of nursing courses in the total number of students. 7. There were very different correlation coefficients between characteristics of self-concept test and academic achievement according to the type of each class and type of courses they learned. 8. Characteristics of self-concept test positively correlated at significant level with total grade point averages and grade point averages of nursing courses of all students were physical self and row variability. Those who have positive concept on their own physical status and who are deficient in self-concept were higher in total grade point averages and grade point averages of professional courses than other students. 9. Scores of professional courses offered in freshmen and sophomore classes were in positive correlation with limited number of characteristics of psychological tests. In pursuit of a tool predicting successful academic achievement of nursing students, their G.P.A. during the junior and senior year of nursing will serve as the more reasonable criteria. 10. Junior students of this school were in higher positive correlation with many psychological factors than other classes.

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시판되고 있는 유사마스크 제품의 여과효율성능 비교평가 (Evaluation of Filtration Performance Efficiency of Commercial Cloth Masks)

  • 장지영;김승원
    • 한국환경보건학회지
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    • 제41권3호
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    • pp.203-215
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    • 2015
  • Objectives: This study was designed to evaluate the filtration efficiencies and pressure drops of five commercial cloth masks (4 plate type, 1 cup type) in comparison to the performance of a class 1 disposable respirator (reference respirator). A further objective was to evaluate the effects of the number of layers and wash treatment independently on filtration efficiencies and pressure drops. Methods: Polydisperse NaCl aerosols were generated in an aerosol chamber and their concentrations were measured by an optical particle counter (OPC) in the size range of $0.3{\sim}10{\mu}m$ (five channels). Results: The filtration efficiencies of the five cloth masks and the reference respirator were D: 9.5%, C: 18.5%, E: 23.6%, A: 28.5%, B: 29.7% and R: 91.1%, respectively, and the pressure drops through them were C, D: 0.8 Pa, E: 1.7 Pa, B: 6.4 Pa, A: 42.7 Pa and R: 19.3 Pa, respectively. The filtration efficiencies of the cloth masks and reference respirator were below the class 1 respirator criterion (${\geq}94.0%$) of the Ministry of Employment and Labor (MOEL) and Ministry of Food and Drug Safety (MFDS). The pressure drops satisfied the class 1 respirator criterion (${\leq}70Pa$) of MOEL and MFDS. When the cloth masks were folded into two and four layers, the filtration efficiencies of cloth masks A, B, C, D (plate type) increased 1.7-4.6 times, and 2.3-6.8 times, respectively, compared to the efficiencies of the same products in a single layer. Pressure drops increased as the number of layers was increased. The filtration efficiency of cloth mask E with a liner was 1.3 times higher than that of the same mask without a liner, and the pressure drop was lower in the no-liner configuration. After a single washing, the filtration efficiencies of all the cloth mask products decreased 1.04-4.0 times compared to those of the same products intact. For the cloth masks C and E, their filtration efficiencies were significantly decreased after washing (p<0.05). The pressure drops of all cloth masks were 1.2-2.0 times lower after washing. Conclusions: The filtration efficiencies of the five cloth masks were below 30% and did not improve greatly by increasing the number of layers. After a single washing, their performances decreased. Considering the above and other issues identified with cloth masks, such as poor fit and stretched fibers through use, people should not expect protection against particulate matters from the cloth masks on the market.

아동비만에 영향을 미치는 일반요인 및 식이섭취 실태에 대한 비만군과 대조군의 비교 연구 -인천시내 초등학교 중심으로- (A Comparative Study of Obese Children and Normal Children on Dietary Intake and Environmental Factors at an Elementary School in Inchon)

  • 이윤주;장경자
    • 대한지역사회영양학회지
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    • 제4권4호
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    • pp.504-511
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    • 1999
  • The purpose of this survey was to investigate the relationship among obese children, dietary intake and environmental factors. Therefore, this survey compared obese children with normal children on dietary intake and environmental factors. The survey were 110 obese children and 110 normal children whose age, height, and sex were same as the obese children of 21 elementary school in Inchon. The statistical analysis of data was completed using SAS program. The results were summarized as follows : 1) The student's obesity was related to parent's obesity and number of their siblings. There were significant differences between obese groups and normal group for these two factors. 2) Meal time of the obese group showed more irregularity than that of the normal group. Otherwise, the normal group were more "piclity" about special food than the obese group(p<0.05). Also obese children showed unconsious eating while reading or watching TV(p<0.01). The normal group attended physical education class more eagerily the obese group(p<0.001). There was no significant difference between obese children and normal children for learning habits. 3) Obese children shoed higher intake of nutrients compared to normal children. Among all the nutrients, minerals and vitamins showed significant differences. Therefore, further study on obese children and their intake of minerals and vitamin is needed. Also, in order to prevent factors which influence obesity, nutrition education at home as well as school was needed.as needed.

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한국절식(韓國節食)의 여행실태(旅行實態)에 관(關)한 지역별(地域別) 비교연구(比較硏究) -강릉, 대구, 대전, 전주지역을 중심으로- (A Comparative Study on Regional Obeserving State of Korean Holiday's Traditional Festive Foods (Centering Around KANGREUNG, DAEJEON, JEONJU and DAEGU Regions))

  • 김향희;황춘선
    • 한국식생활문화학회지
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    • 제6권2호
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    • pp.155-173
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    • 1991
  • This study was conducted to research on the observing state of Korean traditional holidays and the traditional foods related to those days through the questionnaires completed by 578 housewives who live in Kangreung, Daejeon, Jeonju, and Daegu area. For data processing, SAS program was employed, and all data was analyzed by frequency, percentage, and $x^2-square$. The results are as follows; 1. In observing the traditional holidays, more than 90% of housewives who answered the inquiry keep up SEOLNAL, DAEBOREUM, and CHUSEOK, whithout regarding regions. There are larger number of people who keep up IPCHUN, JUNGWHAJEAL, and DANOH in Kangreung and SAMBOK in Daegu than that of other regions (p<.001). Compared to general circumstances, CHOPAIL is more commonly celebrated by older class as well as lower educated class (p<.001) Also, the consequence shows that Buddhists observe IPCHUN, SAMJITANL, CHOPAIL, DANOH, SAMBOK, and DONGJI more commonly compared with other classes (p<.001), IPCHUN, SAMJITNAL, (p<.01). DAEBOREUM, YUDU, SAMBOK, JUNGYANGJEOL, OHIL, and DONGJI (p<.001) are celebrated more generally among extended. 2. On inheritance of the traditional holidays, most of the housewives answered that the SEOLNAL, DAEBOREUM, CHUSSEOK, and DONGJI are to be inherited. Compared to general circumstance CHOPAIL is suggested to be inherited by older people (p<.001). The IPCHUN, CHOPAIL, SAMBOK (p<.001), and DANCH (p<.01) are suggested by Buddhists that YUDU and SAMBOK are by nuclear. 3. In preparaing festive foods, DEOKGUK on SEOLNAL, OHKOKBAP and MUKEUNNAMUL on DAEBOREUM, SONGPYEON and GATEUNNAMUL on CHUSEOK, and PATJUK on DONGJI are being made very generally. KANGJEONG on SEOLNAL, BUREUM on DAEBOREUM, KALGUKSU and SAMGYAETANG on SAMBOK, DARKJIM on CHUSEOK, SUJEONGGWA and DONGCHIMI on DONGJI appeared comparatively high rated of making. 4. In normal times, DEOKGUK, MANDU, INJEOLMI, SIKHYAE, SUJEEONGGWA, PYEONYUK, JEONYUEO, SIRUDDEOK, BOKSSAM, MUKEUNNAMUL, SONGPYUN, MINARINAMUL, YUKGAEJANGGUK, KALGUKSU, SAMGYAETANG, HOBAKJIJIM, TORANTANG, GATEUNNAMUL, NUREUMJEOK, DAKJIM, KALBIJIM, PATJJUK, and DONGCHIMI is usully made. 5. The source to learn about traditional foods is mostly by her mother and the rest orders are husband's mother, cooking books, mass media (including T.V), school education, and cooking instituse, etc.

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1급 응급구조사의 직종에 따른 직무만족도 및 업무스트레스 (Job Satisfaction and Work Stress of EMT-paramedic's According to type of Occupation)

  • 김덕원;최성우
    • 한국산학기술학회논문지
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    • 제18권11호
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    • pp.584-593
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    • 2017
  • 본 연구는 응급구조사가 배출된지 21년이 지난 시점에서 119와 병원에서 근무하는 응급구조사들을 근무 기관별로 업무스트레스와 직무만족도를 비교분석하여 119와 병원의 차이와 장단점을 파악함으로써 우리나라의 1급 응급구조사들의 근무여건을 개선하고 보다 나은 근무환경을 조성하는데 기초자료를 제공하는 것을 목적으로 수행하였다. 광주광역시와 전라남도, 전라북도의 28개 119안전센터와 14개 권역응급의료센터 및 지역응급의료센터에서 근무하는 1급 응급구조사 182명을 대상으로 설문조사를 실시하였다. 통계분석은 SPSS/WIN 20.0을 사용하였으며, 카이제곱검정, t-test, ANOVA, ANCOVA로 분석하였다. 업무스트레스는 119근무자(2.92), 병원근무자(3.01)으로 유의한 차이가 없었다. 직무만족도는 소방근무자(2.98), 병원근무자(2.54)으로 병원근무자들이 크게 유의하게 낮았다(p<0.001). 또한 병원근무자들의 보수 영역에서 가장 낮은 점수가 보였으며($2.07{\pm}0.62$), 월 평균 환자수가 적을수록(p<0.001), 월수입이 높을수록(p=0.047), 휴가가 많을수록(p<0.001) 업무스트레스가 낮고, 직무만족도가 높은 것으로 나타났다. 업무스트레스를 감소시키고 직무만족도를 높이기 위해 119와 병원 모두 근무복지여건의 개선이 필요하고, 119의 경우, 구급대원 폭행 방지 대책과 휴식공간이 필요하고 특히 병원의 경우는 급여와 연간 급여증가율, 고용형태의 안정을 개선해야 한다.

일부 대도시 초등학생의 금연의지와의 관련 요인 (Factors Related with the Intention of Smoking Abstinence among Elementary Students in a Large City)

  • 박순우
    • 한국학교보건학회지
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    • 제22권1호
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    • pp.49-59
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    • 2009
  • Purpose: The aim of this study was to identify the factors related with the intention of smoking abstinence among elementary students in a metropolitan city in Korea. Methods: All the elementary schools in the city were stratified by region, and then schools as a primary sampling units (PSU) were selected by probability proportional to size (PPS) sampling. One class per grade was sampled randomly from 5th and 6th grade in the sampled schools from October to December in 2004. The students completed a standardized self-administered questionnaire anonymously. A total number of 1,712 respondents who did not smoke was included in the final analysis. The dependent variable was an intention of smoking in the future, and it was dichotomized into 'absolutely confident in smoking abstinence' and 'others'. The risk of non-absolute confidence in smoking abstinence was calculated with simple and multiple logistic regression, which were conducted with STATA 9.0 by a design-based analysis considering strata variable, PSU, and sampling weight. Results: In the final model of multiple logistic regression analysis, those who were more likely to have non-absolute confidence in smoking abstinence were male students (OR=2.66, p<0.001); barely attending religious services (OR=3.32, p=0.002) or having no religion (OR=1.95, p=0.027); exposure to environmental tobacco smoke outside home 1${\sim}$2 days per week (OR=1.60, p=0.013); having friends who smoked (OR=1.93, p=0.011); non-absolute confidence in refusing to smoke (OR=5.35, p<0.001); having relatively less negative attitude (OR=2.88, p<0.001), positive attitude (OR=2.35, p<0.001), and indifference (OR=4.05, p=0.034) toward peer smoking; not good relationship with mother (OR=1.52, p=0.016). Conclusion: The factors related with non-absolute confidence in smoking abstinence were coincided with those of smoking among children. The results of this study suggest the smoking prevention education should be applied to the children more actively, especially who are not confident in smoking abstinence in the future.

S-JND 모델을 사용한 주관적인 율 제어 알고리즘 기반의 HEVC 부호화 방법 (A Perceptual Rate Control Algorithm with S-JND Model for HEVC Encoder)

  • 김재련;안용조;임웅;심동규
    • 방송공학회논문지
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    • 제21권6호
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    • pp.929-943
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    • 2016
  • 본 논문에서는 인지 화질을 고려하기 위해 S-JND 모델 기반의 율 제어 알고리즘을 제안한다. 제안하는 율 제어 알고리즘은 인간이 가지는 시각 시스템의 특징을 반영하기 위하여 시각적 민감도와 시각적 관심도를 동시에 반영할 수 있도록 제작된 S-JND (Saliency-Just Noticeable Difference) 모델을 사용한다. 율 제어 알고리즘을 통해 비트를 분배하는 과정에서 픽쳐 내에 존재하는 각 CTU (Coding Tree Unit)가 가지는 S-JND threshold를 구한다. 각 CTU의 threshold는 적응적으로 적절한 비트를 분배하는데 사용되고, 따라서 제안하는 비트 분배 모델은 인지 화질을 향상 시킬 수 있다. 제안하는 방법의 성능 검증을 위해서 제안하는 방법을 HM 16.9에 구현하였으며, CTC (Common Test Condition) RA (Random Access), Low-delay B와 Low-delay P의 경우에 Class B와 Class C 영상들에 대해 실험 하였다. 실험 결과, 제안하는 방법은 기존 율 제어 알고리즘 대비 평균 2.3%의 비트율이 감소했고 BD-PSNR은 약 0.07dB 향상이 있었으며 비트 정확도 또한 0.06% 정도 증가하였다. DSCQS (Double Stimulus Continuous Quality Scale) 방법으로 측정한 결과, 제안하는 방법은 기존 방법 대비 0.03 MOS (Mean Opinion Score) 향상을 보였다.

간호사들의 임상근무의 어려움 관련 주요 요인과 임상근무 활성화 방안 분석 - 현장에서 근무하는 간호사 대상 - (The main difficulties related factors of nurses' clinical work and clinical work plan activation analysis - focus on the nurses working in the field -)

  • 박수경;조경미
    • 한국병원경영학회지
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    • 제21권3호
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    • pp.11-21
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    • 2016
  • The purpose of this study is to investigate the degree of difficulty and turnover of nurses working in the field and to derive clinical work activation and supply policy improvements. Data was collected from December, 2014 to January, 2015, from 23 hospitals, and participants were 3,887 nurses working in the field, Survey details : the difficulty of the clinical work of nurses working in hospitals, turnover intentions status and policy proposals for clinical research work enabled General characteristics, difficulties in clinical working, turnover intention and clinical work plan activation are frequency analysis. The difference between each of the variables in accordance with the general characteristics are one-way ANOVA analysis, Correlation analysis of the variables is also a Pearson correlation coefficients. 'difficulties in clinical working' was a statistically significant difference depending on the type of hospital, nursing class, number of beds, location, age, position, employment, gender, working form, working department, salary, career, and degree level. 'turnover intention' was a statistically significant difference depending on nursing rate, number of beds, region, age, position, sex, shifts, departments, annual income, and career. 'policy recommendation' was a statistically significant difference depending on type of hospital, nursing rate, age, position, employ, shifts, departments, annual income, degree level and career 'difficulties in clinical working' is 'turnover intention' (p<.001), 'policy recommendations' (p<.001) and had a significant positive correlation. and 'turnover intention' had a "policy recommendation" significant positive correlation with the relationship (p<.001) The most difficulties point of the nurses working in the field are the environment, such as shift, urgent and dangerous. Major policy proposals are improve treatment such as wages, and welfare.