• Water for future
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• v.6 no.2
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• pp.12-18
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• 1973

This paper describes the study and test for sand and gravel embankment in winter season and also contribute to the development of construction method for the practical purposes. In order to make possible sand and gravel embankment in winter season, at first, the following eriteria on work are given under the normal weather condition: 1) The maximum diameter of material shall not exceed 30cm and sand content which is the ratio of the weight of sand to gravel shall not exceed 60% 2) Spreading depth shall not exceed 60cm each layer of material shall be compacted by over 6 times passing by thell ton smooth drum type of uibratory roller and the relative density shall exceed 60% In addition to the above conditions, the following criteria are given as winter season condition. 3) Sand contsnt shall not exceed 25%, and water content shall not exceed 4% 4) Dwing construction, the air temperature should be $70^{\circ}C$ below zero at minimum and $3^{\circ}C$ below zero onthe average and all the construction work should he continued without intersuptions. With above criteria, it is come to a conclusion that the conclusion that the construction of sand and gravel embankment in winter season will be done satisfactorily without any difficulty. On the basis of these criteria an actual construction was practiced and it was proved that those criteria are applicable to actual embankment of materials.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1307-1311
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• 2010

수자원의 효율적인 관리를 위해서는 홍수량 자료뿐만 아니라 저 평수량의 자료도 매우 중요하며, 이는 최근의 가뭄 발생으로 인하여 용수공급 및 하천수질관리 문제에서 저수위 유량자료의 파악이 중요한 관심 대상이기 때문이다. 이를 위해서는 저수위에 대해 유량측정을 실시하여 유량자료를 확보해야 하며, 이와 더불어 연속적인 유량자료를 얻기 위해서는 신뢰성 있는 수위-유량관계곡선식이 필수적이다. 일반적으로 자연하천에서 수위-유량관계는 수위의 상승 및 하강에 따라 유량변화가 일정한 경향성을 가지고 변동을 하기 때문에 단일함수 관계로 설명이 가능하다. 하지만 갑문 조작에 영향을 받는 구간에서는 수위와 유량만의 단일함수 관계가 아닌 갑문의 개 폐에 따라 수위와 유량이 변동하는 특성을 가지고 있어 일반하천에 비해 수위-유량관계를 규명하는 것이 매우 어려운 문제이다. 본 연구는 금강 하구둑의 갑문조작에 의하여 배수영향을 받는 규암 수위관측소에 대하여 수위-하강고-유량관계를 이용한 유량환산방법, 수면경사를 매개변수로 추가한 다중 회귀식 개발, 자동유량측정 장치를 이용한 유속지수법, 기존 수위-유량관계곡선식을 이용한 유량환산, ADCP(Acoustic Doppler Current Profiler)를 이용한 유량측정성과에 대하여 비교 분석을 통하여 갑문조작에 의한 배수영향을 받는 지점의 안정적인 유량자료를 제공하는데 목적이 있다. 이와 같이 각 유량환산 방법에 따라 실측 유량과 환산유량 비교의 결과 수위-하강고 유량관계의 경우 평균 26.60%, 기존 수위-유량관계곡선의 경우 130.29%, 유속지수법의 경우 36.48%, 다중회귀식의 경우 24.65%의 상대오차가 발생하였다.

• Membrane Journal
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• v.15 no.4
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• pp.349-354
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• 2005

YSZ (yttria-stabilized zirconia) determined with an electrolyte that analyzed thermal stability along sintering condition and an electric characteristic. As sintering temperature increases by SEM, grain grows and it showed that pore decreases relatively. and confirmed effect by grain size. It evaluated that particle internal resistance and electric performance by resistance in an electrolyte and electricity conductivity measurement through ac impedance measurement in temperature of $800\~1000^{\circ}C$ in 2-probe method In order to recognize an electric characteristic. In dry process and wet process, density was each 6.13, 6.25 $g/cm^3$ and the relative density was each 98, 99$\%$ when sintering condition is $1400^{\circ}C$.

• Journal of Navigation and Port Research
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• v.34 no.5
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• pp.311-317
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• 2010

Mobile Harbor(MH) is a new paradigm for maritime transport system introduced in Korea, the target of which is to carry out ship-to-ship cargo operation rapidly and effectively even under a condition of sea state 3. A MH ship is moored alongside a large container vessel anchored at the defined anchorage and also equipped with gantry cranes for handling containers. The MH study concerned includes rapid container handling system, optimum design for floating structure, hybrid berthing & cargo operation system, design for cargo handling crane, etc. This paper is to deal with a conceptual design of a stabilized mooring system and mooring equipment under a condition of ship-to-ship mooring. In this connection, we suggest a positioning control winch system in order to control heave motions of the MH ship which is to add constant brakepower and stabilized function to an auto-tension winch and mooring equipment used currently in large container ships.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.1
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• pp.1-11
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• 2020

Behaviors of wake vortices generated by an aircraft affect the performance and flight stability of flying aircraft in formation flight. In the present study, the trajectories of the wake vortices behind airplanes in close formation flight were computed using a Fourier spectral method. The behavior of wake vortices showed complex patterns depending on the initial circulation and the relative positions between the vortices. In the initial stage, the wake vortex movement was affected by the nascent vortex. When the vortex becomes closer to the other vortex, then a new trajectory is formed. When the viscous effect becomes dominant, the core radius increases. Thus, a new vortex moving near the existing vortex can have strong interaction with each other, resulting in the complicated behavior of wake vortices. In the future, the ground effect on the behavior of the wake vortices during take-off and landing will be studied.

• Journal of Chest Surgery
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• v.29 no.12
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• pp.1401-1404
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• 1996

Central venous line insertion is an essential procedure in a cardiac operation. For this, percuteneous Insertion is usually done in the internal jugular vein or the subclavian vein. However, this method can create such complications as pneumothorax and hemothorax, and repeated failure in inserting the cathet r, especially in infant and child patients, can waste excessive time. Consequently, in our hospital, catheterization of the innominate vein was done after the completion of sternotomy in the cardiac operation of infant and child patients weighing under 1 Okg. During operation, the catheter was placed in the left atrium through the foramen ovate or pulmonary artery to be used for pressure monitoring. When the patient's hemodynamic became stabilized, the catheter was withdrawn to either the right atrium or superior vena casa to be used as the channel for fluid replacement or drug administration. In our hospital, this procedure has been used in 96 cases since 1989. No complications such as pneumothorax and hemothorax occilrred, and neither bleeding after the removal of the catheter was seen.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.975-975
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• 2012

최근까지 용수확보와 홍수예방, 하천환경관리 등의 목적으로 많은 댐이 건설되어 왔으며 이러한 댐 건설은 주변지역의 자연 및 사회 환경의 변화를 유발하게 된다. 이는 구체적으로 유출특성의 변화로 나타나며 유출특성의 변화는 수자원의 계획과 관리 측면에 상당한 영향을 끼친다. 따라서 정확한 장기유출량의 예측은 이수 측면에서 대단히 중요하며 이에 대한 신뢰성 있는 해석이 수행되어야 한다. 본 연구에서는 SWAT 모형을 이용하여 댐 건설에 따른 유역의 장기유출특성변화를 분석하였다. 충주댐 상류유역을 대상으로 분석기간을 댐 건설 전(1975~1985년)과 댐 건설 후(1986~1995년, 1996~2005년)로 나누어 적용하였고, 해당 관측소에서 제공하는 수문 기상자료와 지형자료를 이용하여 입력자료를 구축하였다. SWAT 입력 모형의 최적값을 결정하기 위해 유출총량 및 첨두유량 감쇄곡선 형태에 영향을 미치는 유출관련 매개변수를 선정하여 보정하였고, 유역 최종 출구점인 충주댐 지점에서의 일 유출자료에 대해 관측치와 모의치를 비교하였다. 그 결과 상관계수는 0.89와 0.71, 모형효율은 0.87과 0.76으로 매우 양호한 결과를 보였으며 이는 SWAT 모형이 장기 유출 모의에 있어 안정적 결과를 제공함을 판단할 수 있었다. 보정된 결과를 바탕으로 장기유출모의결과 계산평균유량과 계산첨두유량 모두 관측결과와 상대오차 10%이하의 만족스러운 결과를 보였으며 댐 건설 전 후의 유출특성 비교결과 전반적으로 댐 건설 이후 유출률이 증가하는 특성이 나타났다. 댐 건설 후 나타나는 유출률 변화를 규명하고자 수문성분별 모의를 실시하였으며 그 결과 지표유출이 4% 증가 하였고 증발산량이 3% 감소하였다. 이는 대상유역의 도시화에 의한 불투수면적의 증가와 산림면적 감소 때문으로 추정되며, 이로 인하여 댐 건설 후 유출률이 소폭 증가하였음이 판단된다. 이상의 결과들로부터 SWAT 모형은 장기 일 유출량 추정 및 유역 전반의 통합관리 측면에서 적용성과 활용성이 우수하다고 판단되며 댐 건설로 인한 자연환경의 변화는 유역의 유출특성의 변화에 영향을 준다는 결론을 얻을 수 있었다. 이러한 결과를 확장하여 댐 건설 이외에 다양한 요소들을 모형에 적용하고 유역개발에 따른 수문환경의 전반적인 변화에 대한 유출평가가 필요하다고 판단된다.

• Journal of Life Science
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• v.17 no.3 s.83
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• pp.444-453
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• 2007

Our genome exists in the form of chromatin, and its structural organization should be precisely regulated with an appropriate dynamic nature for life. The basic unit of chromatin is a nucleosome, which consists of a histone octamer. These nucleosomal histones are subject to various covalent modifications, one of which is methylation on certain lysine residues. Recent studies in histone biology identified many histone Iysine methyltransferases (HKMTs) responsible for respective lysine residues and uncovered various kinds of involved chromatin associating proteins and many related epigenetic phenotypes. With the aid of highly precise experimental tools, multi-disciplinary approaches have widened our understanding of how lysine methylation functions in diverse epigenetic processes though detailed mechanisms remain elusive. Still being considered as a relatively more stable mark than other modifications, the recent discovery of lysine demethylases will confer more flexibility on epigenetic memory transmitted through histone lysine methylation. In this review, advances that have been recently observed in epigenetic phenotypes related with histone lysine methylation and the enzymes for depositing and removing the methyl mark are provided.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.3
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• pp.101-108
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• 2019

Due to recent improvements in computer processing speed and image processing technology, researches are being actively carried out to combine information from camera with existing GNSS (Global Navigation Satellite System) and dead reckoning. In this study, developed a vision-based positioning assistant algorithm to estimate the distance to the object from stereo images. In addition, GNSS/on-board vehicle sensor/vision based positioning algorithm is developed by combining vision based positioning algorithm with existing positioning algorithm. For the performance analysis, the velocity calculated from the actual driving test was used for the navigation solution correction, simulation tests were performed to analyse the effects of velocity precision. As a result of analysis, it is confirmed that about 4% of position accuracy is improved when vision information is added compared to existing GNSS/on-board based positioning algorithm.

• Journal of Digital Convergence
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• v.19 no.1
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• pp.361-371
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• 2021

Communication education research has focused on the effects of instructor characteristics on learning. It is necessary to consider student characteristics as well to develop an effective teaching strategy. The current study tries to classify students into multiple distinct groups depending on their personality traits and communication characteristics and investigates differences in effects of teacher characteristics between those groups. A survey on unversity students was conducted to collect data. A cluster analysis was carried out to identify distint sub-groups of respondents by their personality traits and communication characteristics. The analysis yielded two distinct groups. The two groups were named stable-reticent group', and 'neurotic-talkative group' respectivley. Series of multiple regression were carried out in order to investigate differences in the effects of instructor characteristics. The analyses found different patterns of effects between the two sub-groups. The findings suggest that it is necessary to adopt different communication styles and teaching strategies depending on student types.