• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.1148-1153
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• 2005

하수관거는 국민의 정맥이라고 할 수 있을 정도로 도시의 환경관리와 치수, 쾌적한 환경조성에 있어서 매우 중요한 시설이며 그 규모가 광범위하고 복잡한 네트워크로 구성되어 있다. 이러한 하수관망을 통해 이송되는 물은 지저분하고 냄새가 심하기 때문에 지하에 관의 형태로 대부분 시공되어 왔으며, 상수관망처럼 압력관이 아니라 대부분 중력에 의한 이송방식을 채택하고 있어 문제 발생 시 원인파악과 대처를 힘들게 하는 요인을 가지고 있다. 특히 하수관거의 관리 소홀은 곧바로 토양오염과 인근 환경오염으로 직결되며 장기적으로는 상수를 오염시키는 요인으로 작용하므로 체계적인 방법과 장기적인 안목을 가지고 명확한 분석을 시행할 수 있는 시스템을 가지고 최적으로 유지관리 되어야 한다. 최근 들어 이러한 하수도 시설을 효율적으로 관리 및 개선하기 위해 대도시를 중심으로 근거 조사와 정비 사업이 활발히 시행되고 있다. 그러나, 사업효과를 검증하거나 관로의 유지관리를 위하여 국내 실정에 맞지 않는 외국하수관망 흐름 해석 프로그램을 그대로 사용하고 있고 정확한 해석이 이루어지지 않고 있어 효율적인 유지관리가 어렵다. 이와 같은 문제점을 해결하기 위하여 하수관망해석이나 하수관망 정비시 필요한 불명수산정이 가능하고 국내실정에 맞는 프로그램 개발이 시급한 실정이며, 아울러 프로그램을 효율적 운영하고 관리하는 제어관리 기술을 개발, 진행하고 있다. 본 논문에서는 개발된 프로그램의 부정류 해석 기능을 활용하여 대상구역의 해석을 실시하여 기존분석방법의 I/I결과와 비교하였으며 최적관리를 위한 방안을 제시하였다.준편차가 증가하고 있음을 알 수 있다. 본 연구에서는 상용 CFD모형인 FLOW-3D를 계획 중인 하수처리장의 침전지 유입부 설계에 적용하였으며 저류벽의 위치와 폭, 유공정류벽의 유공율에 따른 유입하수의 분배효과를 분석하였다. 실험을 수행하여 보다 정밀한 공식으로 개선할 수 있었다.$10,924m^3/s$ 및 $10,075m^3/s$로서 실험 I의 $2,757m^3/s$에 비해 통수능이 많이 개선되었음을 알 수 있다.함을 알 수 있다. 상수관로 설계 기준에서는 관로내 수압을 $1.5\~4.0kg/cm^2$으로 나타내고 있는데 $6kg/cm^2$보다 과수압을 나타내는 경우가 $100\%$로 밸브를 개방하였을 때보다 $60\%,\;80\%$ 개방하였을 때가 더 빈번히 발생하고 있으므로 대상지역의 밸브 개폐는 $100\%$ 개방하는 것이 선계기준에 적합한 것으로 나타났다. 밸브 개폐에 따른 수압 변화를 모의한 결과 밸브 개폐도를 적절히 유지하여 필요수량의 확보 및 누수방지대책에 활용할 수 있을 것으로 판단된다.8R(mm)(r^2=0.84)$로 지수적으로 증가하는 경향을 나타내었다. 유거수량은 토성별로 양토를 1.0으로 기준할 때 사양토가 0.86으로 가장 작았고, 식양토 1.09, 식토 1.15로 평가되어 침투수에 비해 토성별 차이가 크게 나타났다. 이는 토성이 세립질일 수록 유거수의 저항이 작기 때문으로 생각된다. 경사에 따라서는

• Korean Journal of Poultry Science
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• v.19 no.3
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• pp.125-136
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• 1992

This study was conducted to estimate the effect of dietary alfalfa meal on the contents of egg yolk cholesterol, the levels of egg yolk pigmentation and the performance of laying hens. Alfalfa meal which was alternated wheat bran was supplied 0, 3.5 and 7%, respectively. Total 192 brown laying pullets of 47 weeks old were randomly assigned to the wire cages from July 23 to October 7, 1991 for 10 weeks. The results obtained were summarized as follows ： 1. The egg production was highest at 3.5% alfalfa meal level during the entire period. But there was no significant difference among treatments. 2. Egg weight increased in treatments 3.5 and 7% alfalfa meal supplementation significantly. (P<0.01). 3. Even though there was no significant difference, the daily egg mass was the highest at 3.5% of alfalfa meal level. 4. Daily feed intake was the highest at 3.5% of alfalfa meal level. However, feed conversion rate was the lowest among treatments. 5. The feed cost per kg egg mass in the treatment of 3.5% alfalfa meal was significantly lower than the other treatments. (P<0.05). 6. Shell thickness and shell weight in terms of egg shell quality were increased as the levels of alfalfa meal were increased. But there was no significant difference among treatments. 7, The egg yolk Pigmentation was improved significantly as the level of alfalfa meal was increased (P<0.01). 8.899 yolk cholesterol contents were decreased in the treatments of 3.5 and 7% alfalfa meal supplementation compared with those in the treatment of wheat bran only(P >0.05). The results of this study indicate that 3.5% alfalfa meal level was most effective and economical in laying hen.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.180-187
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• 2010

The study was performed to investigate the property of rhizosphere microorganisms, and community structure during GMO, and Non-GMO rice cultivation. In the dilution plate technique, there were no significant differences in microbial populations of rhizosplane with genetically modified, and non-genetically modified rice cultivation, and rhizosphere were also the same results. Dominant bacterial genera were Afipia 12.5%, Spingomonas 10.0%, Ramlibacter 10.0%, Mycobacterium 7.5%, and Tetrasphaera 7.5% in rhizosphere soil of genetically modified rice plant, while Afipia 7.3%, Spingomonas 12.2%, Ramlibacter 7.3%, Mycobacterium 17.1%, Tetrasphaera 14.6% in non-genetically modified cultivated at Suwon test fields in 2006. Majorgenera isolated from root surface cultivated in Yesan fields were Arthrobacter 12.7% in rhizoplane of genetically modified plant, and Burkholderia 22.2% of non-genetically modified plant in 2007, Paucimonas 26.6% of genetically modified plant, Chryseobacterium 15.4% of non-genetically modified plant in 2008. Also the microbial communities in rhizosphere soils of genetically modified, and non-genetically modified plants were characterized using phospholipid fatty acid, and denaturing gradient gel electrophoresis. The phospholipid fatty acid profiles of soils in this condition showed different pattern, but did not show significant differences between soils cultivated with genetically or non-genetically modified rice plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.364-369
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• 1989

Leaf characteristics of main stem and tiller of IK type maize (IK/ /IRI/B68) were compared with those of Jinjoo Ok hybrid which are not usually tillered. A total of nine leaves from flag leaf to the third or the fourth leaf below ear-bearing node were sampled from each stem or tiller. There was no significant difference in mean leaf length between IK/ /IRI/B68 and Jinjoo Ok. But the mean leaf width of IK/ /IRI/ B68 was about 2 cm narrower than that of Jinjoo Ok. The mean leaf area of the IK/ /IRI/B68 was also smaller than that of Jinjoo Ok due to the narrower leaf width. There were not significant differences in mean leaf characteristics between main stem and tillers of IK/IRI/B68. The longest leaf was the leaf below the ear-bearing node and the widest leaf was the leaf just above the ear-bearing node. Mean length. width and area of leaf on main stem and tillers were similar. Coefficients of variation calculated for individual leaf indicated that the leaves near the ear-bearing node were more uniform than others. The leaf area measured was significantly greater than that estimated by formular, length x width x 0.75. New constant to estimate leaf area of tillering maize was derived as 0.8.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.1
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• pp.714-721
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• 2018

In this study, we investigate a design technology intended to radically increase the buckling strength of vertically curved panels. Recent studies proposed a buckling strength formula which properly reflects the effect on the local plate buckling strength of flat plates when they are stiffened by closed section ribs. Herein, we attempted to quantitatively evaluate this effect on curved panels and to reveal the correlations with the design parameters. The commercial finite element software, ABAQUS, was used to build a three dimensional numerical model and numerical parametric studies were conducted to evaluate the variation of the buckling strength. In the case of flat panels, the local buckling strength of stiffened curved panels increases proportionally with increasing rotational stiffness of the closed-section ribs. After attaining a limiting value, an obvious tendency was found that the local buckling strength of the stiffened curved panel would converge towards a fixed value when the panels are supported along both sides. The parametric studies performed using the influential design parameters confirmed that the estimated partially-restrained curved panel strength is well correlated with the proposed formula.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.573-584
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• 2013

This study experimentally investigated the change in distribution of wave pressure on the front wall according to the variation of the front wall porosity of the caisson breakwater having the cap of wave chamber. First, the wave pressure for the non-porous caissson corresponding to zero porosity was measured and compared with the pressure formula suggested by Goda(1974). The analysis showed that the measured pressure distribution fairly well agreed with the Goda formula, which confirmed the accurate measurement of wave pressure in the present experiment. In case of the porous caisson, meanwhile, the experiment was performed by varying the front wall porosity as 0.2, 0.25, and 0.3. The wave pressure distribution at the front wall showed little difference according to the porosity for most of the test wave conditions, whereas the pressure slightly increased with the porosity for some test waves whose wave heights and periods were relatively large. However, the difference according to the porsosity was insignificant for the wave force at the front wall.

• Korean journal of communication and information
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• v.36
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• pp.135-161
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• 2006

The aim of this study is to examine who had participated as members of the editorial staffs and their role in the Independent. In spite of the historical significance of the Independent, this topic was not treated properly by related studies. Moreover many studies mainly based on the Philip Jaisohn's autobiography showed the tendency to overemphasize his role. This study tried to overcome the limitations of the existing studies by critical reinterpretation of the historical materials and some new documents. The result of this study shows that 9 persons participated in the Independent. They are Philip Jaisohn, Joo Si-kyung, Yoon Chi-ho, Homer B. Hulbert, Son Seung-yong, Lee Jun-il, Henry Gerhart Appenzeller, H. Emberley and George Cobb. Five person including Jaisohn were Koreans and the rest were foreigners. Hulbert took part in editing English edition confidentially during some month from the beginning. Son Seung-yong seems to be the only one man to participate from beginning to end. Lee Jun-il was not a editorial staff but a treasurer, and Cobb participated temporarily in proofreading. Hulbert and Cobb were not official staff.

• Journal of Korean Home Economics Education Association
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• v.24 no.2
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• pp.51-62
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• 2012

This research examined the method and amount changes of recommended protein intakes(RPI) for male and female adult, and pregnant lactating women from 1962's Recommended Dietary Allowances for Korean(KRDA) to 2010's Dietary Reference Intakes for Koreans(KDRIs) revised. As male and female adult's RPI calculation, factorial method was applied until 1989 KRDA, after that nitrogen balance study was applied. Basal factor in factorial method was standard protein(egg or milk protein) requirement or obligatory nitrogen(protein) loss. On the other hand, basal factor in nitrogen balance study was minimum dietary protein requirement to maintain nitrogen equilibrium balance(nitrogen intake = nitrogen excretion). Adjusting factors of RPI were stress and/or protein requirement difference among people. The RPI of male adults were 50~80 g/day, that of female adults were 45~70 g/day. The additional RPI of pregnant women were 10~30 g/day, were calculate based upon the extra protein needs caused by unborn child development. The pregnant women's additional RPI of 2010's KDRIs revised in the periods of first, second, and third trimester were 0, 15, 30 g/day, respectively. The additional RPI of lactation women were 20~30 g/day, were calculated based upon the extra protein needs caused by maternal milk secretion.

• Korean Journal of Social Welfare Studies
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• v.45 no.2
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• pp.31-63
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• 2014

Recently interest in civic engagement and civic service is increasing. However, in Korea, few studies have focused on civic service. This might be on account of general awareness that civic service is fundamentally different from the basic spirit of voluntary work, while interest in paid volunteer work is on the rise. Thus, it is necessary to examine whether civic service is the real antipode of volunteer work. Under this kind of critical viewpoint, this study aims to analyze civic service based on the attributes of voluntary work and civic service. The major findings are as follows. Firstly, contrary to common belief, civic service has not been established to go beyond the principle of voluntary and unpaid characteristics of volunteer work. Rather, some voluntary work has broken out of principle of voluntary activities. Secondly, civic service and volunteer work might be characterized as different not due to spontaneity and unpaid service but the structural characteristics of the goal, continuity and formality. Furthermore, the reason for the soft landing of civic service in the United States is not because they have supported the reimbursement of expenses and the provision of stipends. Rather, it is because their long-term activities have promoted real community development for the purpose of finding solutions to social problems, and they have derived a sense of pride and satisfaction from social recognition and rewards for their contributions.

• Education of Primary School Mathematics
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• v.24 no.4
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• pp.247-264
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• 2021

The area of a trapezoid is an important concept to develop mathematical thinking and competency, but many students tend to understand the formula for the area of a trapezoid instrumentally. A clue to solving these problems could be found in Dienes' theory of learning mathematics and Watson and Mason' concept of example spaces. The purpose of this study is to obtain implications for the teaching and learning of the area of the trapezoid. This study analyzed the example spaces constructed by students in learning the area of a trapezoid based on Dienes' theory of learning mathematics. As a result of the analysis, the example spaces for each stage of math learning constructed by the students were a trapezoidal variation example spaces in the play stage, a common representation example spaces in the comparison-representation stage, and a trapezoidal area formula example spaces in the symbolization-formalization stage. The type, generation, extent, and relevance of examples constituting example spaces were analyzed, and the structure of the example spaces was presented as a map. This study also analyzed general examples, special examples, conventional examples of example spaces, and discussed how to utilize examples and example spaces in teaching and learning the area of a trapezoid. Through this study, it was found that it is appropriate to apply Dienes' theory of learning mathematics to learning the are of a trapezoid, and this study can be a model for learning the area of the trapezoid.