• 한국지열·수열에너지학회논문집
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• 제6권2호
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• pp.23-28
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• 2010

Fluent ver.6.3 is used as CFD(Computational Fluid Dynamics) simulator to predict the performance of snow-melting system by geothermal pipes energy. As the results of this simulation, it is clearly shown that $50^{\circ}C$ of working fluid in to geothermal evaluated as more effect comparing to $45^{\circ}C$ of working fluid. The Surface temperature is come to $5^{\circ}C$ at 1m/s speed and $50^{\circ}C$ temperature of the working fluid.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집B
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• pp.341-346
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• 2000

This experimental study investigated the flow motion of the working fluid for various diameters of miniature thermosyphons and the performance characteristics for the various amount of the working fluid. The temperatures of condenser surface were measured and visual observations were conducted. The test results show that some fluid condensed in the tube diameters of 0.18cm and 0.22cm is not returned to the evaporator section due to capillary effect so that large temperature gradients are measured. To enhance returning the working fluid, one copper wire of 0.5mm diameter was inserted and the test results show good performance. When the liquid charge was less than 10% in volume dry-out was occurred fur the thermosyphons of the inner diameter of 1.8mm and 2.2mm.

• 동력기계공학회지
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• 제20권2호
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• pp.79-84
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• 2016

The thermodynamic performance of ocean thermal energy conversion with 1 kg/s geothermal water flow rate as a heat source was evaluated to obtain the basic data for the optimal design of cycle with respect to the classification of the working fluid. The basic thermodynamic model for cycle is rankine cycle and the geothermal water and deep seawater were adapted for the heat source of evaporator and condenser, respectively. R245fa, R134a are better to use as a working fluid than others in view of the use of geothermal water. It is important to select the proper working fluid to operate the ocean thermal energy conversion. So, this paper can be used as the basic data for the design of ocean thermal energy conversion with geothermal water and deep seawater.

• 대한안전경영과학회지
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• 제19권4호
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• pp.253-260
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• 2017

Due to dramatic changes in the trend of corporate management in economics, labor and government, companies are being asked to adapt creative and innovative organizational culture in order to keep sustainability. Under the circumstances, flexible working hour becomes one of very effective method for organization culture improvement. Recently, M company has introduced the new policy of working hours that employees can choose a couple of different time options depending on their personal situations. And it turns out to be very effective to work & life balance, increasing organizational vitality, improving efficiency of business and productivity, recruitment of core human resources, and prevention of deviation; both team and personal performance levels has significantly improved. Therefore, it is highly recommended to adapt flexible working policies for companies seeking for a long term, sustainable corporate vision.

• 설비공학논문집
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• 제13권11호
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• pp.1114-1124
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• 2001

The application of carbon dioxide as an attractive natural working fluid in air cooling and heating system is increasingly important in view of the CFC substitution problem. The thermal performance of compact evaporator was analyzed using section-by-section method. The effects of the two-dimensional nonuniformity of air flow through the evaporator is presented. The detrimental effect of the aid flaw nonuniformity on the thermal performance of the evaporator is found to be significant for many typical applications. It is shown that total heat transfer rate of evaporator using $CO_2$ is higher than that using R134a at the simulation conditions.

• 설비공학논문집
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• 제3권4호
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• pp.250-255
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• 1991

Performance analysis of double-effect absorption heat pump system has been done to find improved working pairs (or mixture) by computer simulation. Based on the thermodynamic analysis, the coefficient of performance and mass flow ratio are investigated to compare three aqueous solutions [LiCl-water, LiSCN-LiBr-water, LiCl-$CaCl_2$-$Zn(NO_3)_2$-water] which was developed for only cooling, with conventional LiBr-water solution. It is found that the performances of the new aqueous solutions are better than that of LiBr-water solution not only in cooling systems, but also in heating systems. Theoretical thermodynamic performance data can be used in heat recovery systems by basic design data.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.304-309
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• 2015

On construction sites, it is important to monitor the performance of construction equipment and workers to achieve successful construction project management; especially, vision-based detection methods have advantages for the real-time site data collection for safety and productivity analyses. Although many researchers developed vision-based detection methods with acceptable performance, there are still limitations to be addressed: 1) sensitiveness to the shape and appearance changes of moving objects in difference working postures, and 2) high computation time. To deal with the limitations, this paper proposes a detection algorithm of construction equipment based on Integral Channel Features. For validation, 16,850 frames of video streams were recorded and analyzed. The results showed that the proposed method worked in high performance in terms of accuracy and processing time. In conclusion, the developed method can help to understand useful site information including working pattern, working time and input manpower analyses.

• 가정간호학회지
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• 제4권
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• pp.30-40
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• 1997

The change in health care environment increases the importance of Visiting Nursing Services Program. It has been performed by nurses of district health centers in Seoul since 1991. The Achievement of Visiting Nursing Services Program will be dependent upon their activities. The purpose of this study was to identify the Performance of Visiting Nurses and Job satisfaction of district health centers in Seoul. Therefore, it was to provide the fundamental data development of Visiting Nursing Services Program. The subjects were 214 Visiting Nurses of district health centers in Seoul. The data was collected by self reporting questionnaire from April 15 to April 30, 1997. Their performances and various supportive factors were measured with the instruments developed by the researcher. Job satisfaction were also measured by the instrument developed by Slavitt et al. (1978) was used. The data were, analyzed by Cronbach Alpha, mean, standard deviation, percentage, t -test, ANOVA Duncan test, Correlation Coefficient, and Stepwise Multiple Regression with SAS program. The results of this study were as follows: 1. The average of budget of Visiting Nursing Services Program of district health centers was 0.9% and the average of visiting nursing services personnel of district health centers was 10.1%. 2. With regard to the job satisfaction of Visiting Nurses the mean score was 2.92 out of 5. While the level of Job prestige / status presented as a mean score of 3.48 which was the largest among the 7 components of job satisfaction, the level of administration was the lowest showing 2.57 scores respectively. There were significant differences in the job satisfaction by age, working career of health centers(p<0.01, 0.001). 3. The average of the performance level of Visiting Nurses variables was 2.29; The variable with highest degree of performance was the teaching & consultation, establishment of performance plan, whereas the on with the lowest degree was the directive nursing services. The significant difference was found in performance level according to age, structure type of visiting nursing services, working career of health centers and working career of visiting nursing services(p<0.05). 4. With regard to the perception of the performance expertise by the Visiting Nurses the mean score was 2.37 : The variable with highest degree of performance expertise was the teaching & consultation, establishment of performance plan, whereas the on with the lowest degree was management of home-environment. The significant difference was found in performance expertise according to working career outside of health centers(p<0.05). 5. With regard to the perception of the performance necessity by the Visiting Nurses the mean was 2. 40 : the variable with highest degree of performance necessity was the teaching & consultation, establishment of performance plan, whereas the on with the lowest degree was directive nursing services. The significant difference was found in performance necessity according to working career of visiting nursing services(p<0.05). 6. A positive correlation was found between job satisfaction and performance level(r=.3731, P<0.001). Also, a weak positive correlation was found between the components of job satisfaction and performance level. 7. Stepwise multiple regression analysis revealed that the most powerful predictor was the variance of job satisfaction(R=.3557, $R^2$=.1265). Structure type of visiting nursing services and working career of visiting nursing services accounted for 19.0% of the variance in performance level in nurses. In conclusion, Job satisfaction, Structure type of visiting nursing services and Working career of visiting nursing services variables had influenced on performance level in health centers. Further research is required to confirm these findings.

• 한국콘텐츠학회논문지
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• 제11권1호
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• pp.254-265
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• 2011

본 연구는 J도 소방안전본부 산하 119구급대 60명을 대상으로 하였으며, 연구 기간은 2009년 12월 1일 부터 2월 10일까지였다. 어려운 기관내삽관 교육 전.후 비교 및 일반적 특성에 따른 지식, 자신감, 학업적 자기효능감, 술기수행 능력을 SPSS 14.0을 이용하여 분석한 결과는 다음과 같다. 1. 지식, 자신감, 학업적 자기효능감, 술기수행 능력 모두 교육 전보다 교육 후 유의미하게 증가하였다. 2. 일반적 특성에 따른 교육 전 후 지식은 성별과 병원근무경력에서 모두 유의한 차이를 보였고, 자신감은 계급과 병원경력에서 모두 유의한 차이를 보였다. 학업적 자기효능감은 계급과 병원경력 및 학력에서 모두 유의한 차이를 보였다. 술기수행 능력은 유형 1에서 119구급대 근무경력, 유형 2에서는 대원의 연령과 최종학력이 유의한 차이를 보였으며, 유형 3은 119구급대 근무경력과, 병원에서 근무경력이 교육 후 유의한 차이를 보였다. 유형 4는 연령과 계급에서 교육 전 후 유의한 차이를 보였다. 결론적으로, 119구급대의 기도유지술에 관심을 갖고, 정확한 기관내삽관을 배울 수 있도록 자신감을 함양시킬 수 있는 교육 프로그램이 절실히 필요하다고 사료된다.

• Journal of Advanced Marine Engineering and Technology
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• 제40권6호
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• pp.476-483
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• 2016

해양온도차발전용 유기랭킨사이클은 해양의 표층수와 심층수사이의 온도차를 이용하여 발전하는 사이클이다. 작동유체는 유기랭킨사이클의 열역학적 성능에 있어 중요한 요소이다. 유기랭킨사이클의 열역학적 분석방법으로 핀치포인트분석이 있다. 본 연구는 열교환기내 핀치포인트온도차의 변화와 열원 및 열침의 출구온도의 변화에 따른 열역학적 성능분석을 수행하였다. 핀치포인트분석법에 따라 설계한 해양온도차발전용 단순랭킨사이클에 7종의 단일 작동유체를 적용하여 열역학적 성능을 분석하였다. 성능분석결과 열교환기에서 핀치포인트온도차와 열원 및 열침의 온도변화가 작을수록 사이클 총 비가역성 및 총 엑서지 파괴인자가 감소하였으며, 제2법칙 효율은 상승하였다. 또한 비가역성은 열역학적 변화가 발생한 곳에서 크게 변화하였다. RE245fa2는 선정한 작동유체 중에서 가장 우수한 열역학적 성능을 보여주었으며, 모든 작동유체의 성능은 유사하였다. 열교환기 및 작동유체 선정에 있어 열역학적 성능과 함께 다양한 요소들에 대해서도 엄밀한 이론적 근거가 필요하다.