• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.884-891
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• 2016

A secondary injection system in a diesel engine has benefits: it can be controlled independently without interrupting engine control, it can be adapted to various layouts for exhaust systems, and it pose no reductant dilution problems compared to post injection systems in the combustion chamber or other supplemental reductant injections. In a secondary injection system, the efficiency of the catalyst depends on the method of reducing the supply. The reductant needs to be maintained and optimized with constant pressure, the positions and angles of injector is a very important factor. The concentration and amount of reductant can be changed by adjusting secondary injection conditions. However, secondary injection is highly dependent upon the type of injector, injection pressure, atomization, spray technology, etc. Therefore, it is necessary to establish injection conditions the spray characteristics must be well-understood, such as spray penetration, sauter mean diameter, spray angle, injection quantity, etc. Uniform distribution of the reductant corresponding to the maximum NOx reduction in the DeNOx catalyst system must also assured. With this goal in mind, the spray characteristics and impingement plate types of a secondary injector were analyzed using visualization and digital image processing techniques.

• Journal of Korea Water Resources Association
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• v.48 no.5
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• pp.409-423
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• 2015

In this study the very short-term rainfall forecasting and storm water forecasting using the weather radar data were implemented in an urban stream basin. As forecasting time increasing, the very short-term rainfall forecasting results show that the correlation coefficient was decreased and the root mean square error was increased and then the forecasting model accuracy was decreased. However, as a result of the correlation coefficient up to 60-minute forecasting time is maintained 0.5 or higher was obtained. As a result of storm water forecasting in an urban area, the reduction in peak flow and outflow volume with increasing forecasting time occurs, the peak time was analyzed that relatively matched. In the application of storm water forecasting by radar rainfall forecast, the errors has occurred that we determined some of the external factors. In the future, we believed to be necessary to perform that the continuous algorithm improvement such as simulation of rapid generation and disappearance phenomenon by precipitation echo, the improvement of extreme rainfall forecasting in urban areas, and the rainfall-runoff model parameter optimizations. The results of this study, not only urban stream basin, but also we obtained the observed data, and expand the real-time flood alarm system over the ungaged basins. In addition, it is possible to take advantage of development of as multi-sensor based very short-term rainfall forecasting technology.

• Journal of The Korean Association For Science Education
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• v.30 no.6
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• pp.752-769
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• 2010

The purpose of this study was to apply the microgenetic analysis method for development of information on an individual's change in a certain area during a consistent time period to seek change in scientific questions that elementary school students create. The study subjects were six 6th graders in I elementary school located in Kyunggido with the students conducting 6 sessions of two observational tasks about dry grapes contained in soda pop and candlelight. Information were collected through students' scientific question development paper, record of field observation and interviews. The results of this study are as follows: first, the number of scientific questions that the elementary school students developed showed a tendency for reduction; second, the changes in type of scientific questions bring different results, which depend on a particular characteristic of the tasks; third, By observing pattern changes in scientific questions of each individual, it was found that different results show for each time for the same task, which in other words means that there exists variability within an individual. Also, variability between individuals were shown by confirming that the change pattern for each person were diverse. Thus, the result of this study shows the following implications on education of scientific question development. For students, scientific question development mean more opportunities to increase the process of developing and acquiring knowledge. Therefore, it is important to create situations where one can come up with scientific questions. In addition, analysis in tasks' nature when selecting tasks would be necessary to develop diverse scientific questions.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.4
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• pp.1039-1044
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• 2007

We investigated the residual contents of sulfur dioxide ($SO_2$) on the 280 kinds of herbal medicines distributed at 8 cities including in Seoul, Busan, Daegu, Gwangju, Jecheon, Yeongju, Geumsan and Jeonju in Korea. The residual contents of $SO_2$ were determinated by modified Monier-Williams method. The residual contents of $SO_2$ were not detected at 206 products in total 280 products. However, it was detected below 100 ppm in 39 products, between 101 and 1000 ppm in 30 products and exceeded 1000 ppm in 5 products. $SO_2$ contents ranged 11 ${\sim}$ 2339 mg/kg (mean 293 mg/kg) at domestic samples distributed. Regardless of region, $SO_2$ contents were not found at Notopterygii Rhizoma, Ligustici Scinensis Rhizoma et Radix, Bombyx Batryticatus, Coicis Semen, Cnidii Rhizoma, Anemarrhenae Rhizoma, Gardeniae Fructus, Alismatis Rhizoma. But it's found at Batatatis Rhizoma, Paeoniae Radix and Codonopsitis Radix of every region collected the samples. $SO_2$ contents were not detected at 58 products which collected cultural fields of dometic. After treated with water wash and hot water extraction, the reduction rates of sulfur dioxide were appeared with 14.3% ${\sim}$ 40.4% and 55.2% ${\sim}$ 100.0%, respectively. These data will be used to establish a criteron of residual sulfur dioxide in herbal medicines.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.117-124
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• 2013

Emergency operating procedures(EOPs) of nuclear power plants should be described considering the cognitive capability and limitation of operators and provide appropriate information in the aspect of human factors. Procedures which doesn't consider cognitive characteristics of operators can become causes of human errors. In previous researches, in order to reduce these problems related to the description of EOP, an improvement suggestion for EOP writer's guide has been proposed, which is reflected human factors aspects that should be considered when describing EOPs. The proposed items, however, have a necessity to be validated because it was listed from various documents such as standards and guidelines without any special validation process. For that reason, in this study, a validation process were performed to show that procedures, which are described in compliance with the requirement items proposed in the improved EOP writer's guide, have positive effects in the aspects of human errors and performance comparing with previous procedures. Experiments were performed to compare the performances of two tasks which are described in compliance with each writer's guide of before and after the improvement During each task was performed in experiments, changes of physiological responses such as EEG and ECG were measured to evaluate the cognitive workload and the stress of operators in each task. And also, as the performance, frequencies of errors and cognition speeds of each task were evaluated. In the results of the experiment, the portions of the ${\beta}$ wave decreased in the tasks overall after the improvement. In the case of ECG, change rates of the mean of R-R interval were decreased in the tasks after improvement. In the results of the performance, the cognition and the response time of the tasks after the improvement were predominant with statistical significancies. Error times in the tasks after improvement were decreased or same to the tasks before improvement. Conclusively, it was validated that the procedures were described in compliance with the improved EOP writer's guide had effects on the reduction of human errors and improvement of performance.

• Journal of Biomedical Engineering Research
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• v.21 no.4
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• pp.391-401
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• 2000

Flow through compliant tubes with linear taper in wall thickness is numerically simulated by finite element analysis. For verification of the numerical method, flow through a compliant stenotic vessel is simulated and the results are compared to the existing experimental data. Steady two-dimensional flow in a collapsible channel with initial tension is also simulated and the results are compared with numerical solutions from the literature. Computational results show that as cross-sectional area decreases with the reduction in downstream pressure, flow rate increases and reaches the maximum when the speed index (mean velocity divided by wave speed) is near the unity at the point of minimum cross-section area, indicating the flow limitation or choking (flow speed equals wave speed) in one-dimensional studies. for further reductions in downstream pressure, flow rate decreases. The flow limitation or choking consist of the main reasons of waterfall effect which occurs in the airways, capillaries of lung, and other veins. Cross-sectional narrowing is significant but localized. When the ratio of downstream-to-upstream wall thickness is 2, the area throat is located near the downstream end. As this ratio is increased to 3, the constriction moves to the upstream end of the tube.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.10
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• pp.6114-6125
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• 2014

This paper analyzed the issues related to focus on farmers behaviors of energy saving facilities. This study conducted questionnaire and field surveys of controlled horticulture farmers and economic analysis using an IPA(Importance-Performance Analysis) matrix. According to the research results, the performance level was low on average ranging from 2.33 to 2.56 in a five point Likert-scale on greenhouse mandarin and grape-related facilities. On the other hand, the importance levels were high in the mean rating from 2.69 to 4.8. The results show that energy loss reduction of complementary facility and alternative energy supply support for low cost implementation are more important in terms of the respondents concerns than performance quadrant III. Therefore, it is important to provide financial support to energy-saving facilities to promote the use of energy efficiency improvement. In addition, the government should invest continuously in research and development.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.103-103
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• 2012

본 연구에서는 시험포장($1276.6m^2$)에서의 지표피복 BMPs (Best Management Practices) 시나리오를 적용하여 얻은 평균 유출저감율을 HSPF 모델에 적용하여 유역차원에서의 비점원오염 저감효과를 평가하고자 한다. 본 연구에서는 별미천 유역($1.21km^2$)을 대상으로 모형의 적용을 위한 입력자료로 기상자료와 지형자료를 구축하였으며 기상자료로 수원, 양평, 이천 기상관측소 자료를 구축하였으며, 지형자료로 격자크기 2m의 DEM (Digital Elevation Model)과 토지이용도는 2006년 5월 1일 QuickBird 영상을 제공받아 기존 환경부, 건교부, USGS의 토지피복분류체계 및 현장조사를 통하여 QuickBird 영상으로부터 추출 가능한 정밀농업정보에 대한 항목을 결정하였으며, 정사보정된 QuickBird 영상을 스크린 디지타이징 기법(On-Screen Digitizing Method)을 이용하여 총 21개 토지이용항목의 정밀토지이용도를 구축하였다. 실제모니터링으로 측정된 자료를 바탕으로 수위-유량곡선 산정 및 오염부하곡선을 선정, 2011년 6월 8일부터 10월 31일 분석기간으로 HSPF 모델링을 실시하였으며 모의결과 월별 통계에 따른 적용성 분석으로 RMSE (Root Mean Square Error) 는 1.15 ~ 1.76(mm/day), $R^2$는 0.62 ~ 0.78, Nash-Sutcliffe model efficiency (NSE)는 0.62 ~ 0.76로 모의치는 실측치와 유의성이 있는 것으로 분석되었다. 또한, Sediment, T-N, T-P의 $R^2$는 각각 0.72, 0.62, 0.63으로 상관성을 보이는 것으로 분석되었다. 시험포장으로부터 얻어진 event별 볏짚을 이용한 지표피복시나리오적용 후 밭에서의 평균 유출 약 10 % 유출율 감소 조건과 실제 평균 비점원오염 저감효과 89.7 % ~ 99.4 %의 결과로부터 지표피복효과의 침투효과를 HSPF 모델로 적용하기 위해 침투량(INFILT)를 조절하여 평균유출 약 10 %가 감소되는 16.0 mm/hr 값을 선정하였다. 그 결과, Sediment. T-N, T-P의 평균 저감율은 각각 87.2 %, 28.5 %, 85.1 %로 나타났으며 이는 시험포장에서의 실제 평균 비점오염 저감효과 89.7 % ~ 99.4 %에 근접함을 알 수 있었다. 이 결과로부터 침투량 조절에 따른 지표피복(침투짚단)효과는 Sediment, T-P에서 저감효율이 80 % 이상으로 높았지만 T-N은 약 30 %로 낮은 저감율을 보임으로써 저감효과가 크지 않음을 나타냈다.

• Journal of Nutrition and Health
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• v.39 no.2
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• pp.160-170
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• 2006

This study was conducted to provide foundation data for making health care policy for married women by assessing the dietary intake between highly educated married, employed and unemployed women. It is a direct interview, cross-sectional study with 24-hour recall method for one day. In selecting the subjects for this study, married, unemployed women were selected from a certain area (Daedeok Science Town) in Daejeon where there are high rates of highly educated women, and the married, employed women were selected from the teaching profession in order to avoid confounding due to including a variety of jobs. According to the Korean Standard Classification of Occupations, teaching is the representational occupation of highly educated, married women. Then, to prevent confounding due to age, we selected the subjects out of each age group at the same rate through random sampling. Women who had not graduated college, worked only part-time, or had no current spouse were excluded. As a result, 486 highly-educated, married, unemployed (250) and employed (236) women were used for analyzing data. The unemployed women consumed a higher amount of fat, cholesterol, sodium, vitamin C and folic acid while the employed women consumed a higher amount of iron, vitamin $B_l$ and vitamin $B_2$. P/M/S ratio being 1/1.18/1.05 and 1/1.05/0.87, for the unemployed women and the employed women, respectively, unemployed respondents had a higher saturated fat intake than those of employed. It is in excess of the standard ratio (1/1/1) of the Korean RDA. At the same time, in unemployed respondents the percent of energy intake from fat (24.8%, 23.2%) and animal fat (12.4%, 11.4%) were higher than those of employed respondents. The mean daily nutrient intake of calcium, zinc, and iron for both groups of respondents were lower than the Korean RDA. Both groups had phosphorus as the highest nutrient and calcium as the lowest nutrient of INQ (Index of Nutritional Quality) while nutrients with the INQ being less than 1 were calcium and iron. To sum up, the following conclusions can be made: Nutrition education and guidance for reduction of the intake of fat, especially animal fat, are necessary for unemployed women. In addition, highly educated, married, unemployed and employed women should increase the consumption of foods rich in iron and calcium to prevent anemia and osteoporosis, while decreasing the intake of phosphorus to balance proportions of calcium and phosphorus.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.88-96
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• 2020

It were found that the heavyweight waste glass can be used as a construction materials including concrete from previous experimental studies. In this study, in order to evaluate the structural behavior of RC members using heavyweight waste glass as fine aggregate, a flexural behavior test was performed. And then, its results were compared with those obtained from non-linear finite element model analysis. From the results, when the heavyweight waste glass as fine aggregate in RC member, the area of compressive crushing and the number of cracks increased, however, the mean of cracking spacing decreased. Also it had reduced the ductility at high loading stage. For this reason, the same analysis method about the RC member using natural sand as fine aggregate did not predict the initial stiffness, yield load and maximum load on the flexural behavior of the RC members using heavyweight waste glass as fine aggregate. On the other hand, when it is analytically implemented the reduction of neutral axis depth due to developed compression crushing, the results of non-linear finite element analysis could be predicted the experimental results, relatively well.