• 한국환경복원기술학회지
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• 제6권1호
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• pp.51-56
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• 2003

The urban stream include the channel and its adjacent banks, or hillslopes and it consists of various landscape elements. The riparian ecosystem is important to people. Its water is extracted for irrigation and drinking supplies. Biodiversity and many wetland species are protected here. The riparian ecosystem is diverse and needs to be preserved well. So, it is necessary to measure the features of the urban stream accurately to figure out the change of the riparian ecosystem. However, the traditional Electronic Distance Measurement(EDM) surveying is difficult to measure the curvilinear features of the stream - e, g, angle, curve. The beacon Differential Global Positioning System(DGPS) can handle to measure the curvilinear shape. Therefore, the purpose of this study is to measure the change of the river bed in urban stream accurately using realtime beacon DGPS, and ultimately to provide the basic data for identifying the change of the river ecosystem.

• 한국관개배수논문집
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• 제17권2호
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• pp.71-81
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• 2010

Stream Pilot Project, which began in May 2003 and finished in December 2003, was selected to develop effective methods applicable to nature-like streams. Stream restoration projects aim to maintain or increase ecosystem goods and services while protecting downstream and coastal ecosystems. Fields environmental monitoring such as flow discharge and precipitation were conducted along the Idong stream for amount of channel zone change in 2007. This study selected three monitoring positions to measure the water level and discharge of flowing water. A stage-discharge relation is obtained from direct discharge measurements for three stations by fitting an empirical relationship to the data set. Since discharge measures are made only for low flow conditions, a curve of discharge against stage can then be built by fitting these data with a power curve. And this study used data obtained from floodmark checkup as well as HEC-RAS model to analyze the hydrodynamic characteristics of monitoring sites. Reach-averaged hydraulic parameters for the supply reach were calculated from the small area's HEC-RAS model for Idong stream, and a HEC-RAS model used to analyze hydraulics for a period in 2007, after the stream was considered bank stabilization.

• 한국농공학회지
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• 제42권3호
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• pp.5-17
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• 2000

The story of route of wet-rice diffusion to Korean peninsular is so far known only piecemeal. It is however commonly agreed that wet-rice technology may have spread the western coastal area in Korea from the lower and middle reaches of the yangzi river in China and to the Shandong peninsular and Bohai Bay region and was then transmitted overland to the area in Korea. Recently excavated three prehistoric paddy fields in Korea provide crucial evidence that helps to solve many of the important problems associated with technological diffusion. Research on the paddy field system and irrigation technology of prehistoric wet-rice has been so far especially productive in Japanese archaeology. Judging from the fact that the Yayoi wet-rice agricultural technology in Japan was transmitted by the Korean Strait from the southern part of Korea it is assumed that people in both regions may have practiced the same technology in prehistoric time. This paper examines three prehistoric paddy fields system(the Majon-ri site the Kwanchang-ri site and the Mujon-dong site) in relation to those of japanese data. The conclusions are as follows ; First early wet-rice agriculture in korea was limited by the level of technology and the size of labour. Secondly the location of field itself was restricted to the lower land and valley bottom area. Thirdly the layout of channel and field network is not very much different from the modern paddy field system.

• International Journal of Fluid Machinery and Systems
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• 제7권2호
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• pp.68-79
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• 2014

The type of turbine developed is based on the very low head of water potential source for the electric power production. The area of research is focused for the axial water turbine that can be applied at the simple site open channel with has a very low cost and environmental impact compared to the conventional hydro installation. High efficiency of axial turbine which applied to the very low potential head will made this type of turbine can be used at wider potential site. Existing irrigation weir and river area will be the perfect site for this turbine. This paper will compare the effects of the variation of swirl velocity criterion during the design of the blade of guide vane and rotor of the turbine. Effects of the swirl velocity criterion is wider known as a vortex conditions (free vortex, force vortex and swirl velocity constant), and the free vortex is the very popular condition that applied by most of turbine designer, therefore will be interesting to do a comparison against other criterion. ANSYS Fluent will be used for simulation and to determine the predictive performance obtained by each of design criteria.

• 대한후두음성언어의학회지
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• 제29권2호
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• pp.67-69
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• 2018

The development of office-based, unsedated transnasal esophagoscopy (TNE) has proven to be a major technological advance and with time and experience the application of this technology is becoming more widespread. TNE has allowed otolaryngologists to perform a variety of diagnostic and therapeutic procedures in the office setting. Studies consistently demonstrate that the image quality and diagnostic capability of TNE is equivalent to conventional esophagoscopy. The modern TNE endoscopes offer high quality optics, air-insufflation, and irrigation capability through a 2-mm working channel, and the ability to perform biopsies and select procedures. In general, the role of TNE in the head and neck patient is three-fold : to screen for synchronous and metachronous esophageal squamous cell carcinoma (ESCC) ; to differentiate post-treatment changes/symptoms from malignancy ; and to perform certain office-based procedures. TNE offers many specific advantages to the head and neck patient that are not afforded by conventional esophagoscopy. Because of surgical and postirradiation changes, many HNSCC patients have trismus or neck stiffness preventing completion of conventional transoral esophagoscopy. Perhaps most importantly, TNE provides enhanced patient safety, increased tolerability, better practice efficiency, and cost savings. For these reasons, TNE has become a particularly useful tool in the otolaryngologist's armamentarium.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.155-155
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• 2022

Low head, ogee spillways is popularly used to defense against floods as well as to provide water for irrigation. Spillway is also used to assess compliance with water quality regulations by controlling amount of discharge to the downstream of a channel. For the purpose of water resource management and/or environmental aspects as explained above, the flow discharge through spillways need to be correctly rated as a function of geometry and hydraulic variables. Typically, four flow conditions are encountered during the operation of spillway: (a) uncontrolled free flow (UF); (b) uncontrolled submerged flow (US); controlled free flow (CF); and controlled submerged flow (CS), and each condition has a unique rating equation. However, one of the tricky part of the spillway operation is finding correct flow type over the spillway because structures can operate under both submerged and free flow conditions, and the types are continuously changing over time depending on the amount of discharge, head water and tail water elevation. Quite obviously, if the wrong rating curve relationship is applied because of misjudgment of the flow type due to a transition, a serious error can occur. Thus, an hydraulic model study of one of spillway structure located in South Florida was conducted for the purpose of developing transition relationships. In this presentation, US to UF transition is highlighted.

• 한국산림과학회지
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• 제90권1호
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• pp.90-104
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• 2001

이 연구는 지난 3년간 북경임업대학교와 공동연구과제로 중국의 사막화방지 및 방사기술개발을 위한 연구의 일환으로 사막화현황 및 녹화기술수준조사 및 평가를 위하여 수행되었으며, 특히 본고에서는 중국의 황막사지에 대한 녹화기술을 분석하고자 하였다. 사막화지역 식생분포의 일반적인 특징은 부분적으로 집중된 식생분포, 즉 사막의 저지대 또는 분지의 낮은 곳의 사구에 있는 사막식물, 염수호 주변의 내염성식물, 담수 염수호와 하천연안의 포플러 및 위성류의 군생, 사력퇴적지(고비)의 사퇴식생, 하천선상지의 초생지 및 오아시스(녹주(綠洲))숲 등이다. 일반적으로 사막화지역에는 중국식물명(中國植物名)으로 정류(檉柳)(홍류(紅柳))(Tamarix chinensis Lour.), 사사(梭梭)(Haloxylon ammodendron Bunge.), 사괴조(沙拐棗)(Calligonum Spp.), 호루(胡楊)(Populus euphratica Oliver.), 사조(沙棗)(Elaeagnus angustifolia L.), 유(楡)백유(白楡)(Ulmus pumila L.), 류류(柳類)(Salix spp.), 암황시(岩黃蓍)(Hedysarum spp.), 금계아(錦鷄兒)(Caragana spp.), 문관과(文冠果)(Xanthoceras sorbifolia Bunge.), 백자(白刺)(Nitraria tangutorum Bobr.), 호기자(胡技子)(Lespedeza bicolor), 낙타자(駱駝刺)(Alhagi sparsifolia Shap.), 자산감(刺山柑)(Capparis spinosa L.), 사호(沙蒿)(Artemisia arenaria DC.) 등이 널리 분포하며, 이와 같은 사막화지역 자생식물에 관한 연구가 더욱 필요한 상황에 있다. 풍식지역에서는 합리적인 경작체계(지역계획, 방풍림체계 및 오아시스보호체계, 관개수로네트워크설치, 광대한 농지관리기술 등), 식물자원의 합리적 이용기술(연료림, 약용식물, 방목, 초지관리 등), 수자원이용(유역계획 및 관리, 수로건설, 절수관개기법 등), 방풍림조성, 인구증가의 조절, 농용림 연료목 사료증산기술 등에 관해서, 그리고 수식지역에서는 합리적인 토지이용기술, 식생이용기술, 공학적기술, 농작물보호기술 개발 등에 관한 시험연구사업이 중점적으로 추진되고 있다. 또한, 사막화지역에서의 염성토양 알카리토양개량을 위한 수리적(관개, 배수, 세탈, 수도재배 등), 농업적(토지정리, 경작, 시비, 파종, 윤작, 혼작, 객토 등), 생물적(내염성 작물 및 녹비의 재배, 조림 등) 방법 등에 관한 시험연구도 활발하게 추진되고 있으며, 이와 같은 사막화지역의 녹화사업에 국제적인 협력을 절실하게 요망하고 있다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.476-476
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• 2022

농업용수는 전통적 기능으로 농업용수 그 자체로서의 기능과 시대적 요구에 따른 지역용수로서의 기능을 가진다. 농업용수 그 자체의 기능으로 가장 중요한 것은 관개용수이며, 논, 밭관개, 하우스 시설농업에의 용수공급이다. 농업용수의 실 수요량 측면에서는 논용수가 전체용수 수요량의 60.1%로 가장 많은 양을 차지하고 있으며, 다음으로는 밭용수가 18.6%, 그 외 생활용수, 공업용수, 환경용수, 축산용수 등으로 이용되고 있다. 농업용수 수요 측면에서 논용수의 비중이 가장 높게 나타나기 때문에 본 연구에서는 농업용수 공급에 따라 농업용저수지-관개수로-논에 이르는 공급단계별 수질변화를 분석하였다. 본 연구는 경기, 충남 권역의 오염도가 높은 3개 농업용저수지를 대상으로 하였으며, 농업용수를 본격적으로 공급하는 5월부터 관개가 종료되는 10월까지 농업용저수지와 관개수로, 논을 대상으로 수온, TOC, Chl-a 등 10개 항목을 분석하여 나타내었다. 연구기간동안 수온의 변화는 18.6~34.6 ℃로서 관개수로에 가장 낮고, 논에서 가장 높은 값을 보여 주었으며, 공급단계별 평균 수온은 저수지(R) 27.6 ℃, 관개수로(C) 26.4 ℃, 논(P) 28.4 ℃로 논에서 수온증가가 나타났다. pH는 7.4~9.7의 범위로 저수지에서 최고값, 논에서 최저값을 보였으며, 공급단계별 평균값은 R 9.1, C 8.3, P 8.0으로 저수지, 수로, 논으로 이동하면서 감소하였다. 전기전도도(EC)는 저수지 수질오염도에 따라 다양하게 나타났으며, 공급단계별 평균값은 R 706.3 uS/cm, C 585.5 uS/cm, P 771.2 uS/cm로 논에서 가장 높은 값으로 보였으며, 이는 논에서 추가적인 영양분 공급에 의한 것으로 보였다. 평균 용존산소량(DO)은 R 6.3, C 4.0, P 4.5로 저수지에서 가장 높고, 수로에서 가장 낮게 나타났다. 유기물 지표인 COD와 TOC의 변화를 보면 평균 COD R 21.7 mg/L, C 14.5 mg/L, P 22.7 mg/L, 평균 TOC R 11.2 mg/L, C 8.5 mg/L, P 12.3 mg/L로 두 항목 모두 논에서 가장 높은 값을, 수로에서 가장 낮은 값을 나타내었다. 반면 엽록소 a 평균 농도는 R 128.4 mg/m³, C 54.3 mg/m³, P 31.7 mg/m³로 저수지의 내부생산으로 다량 발생한 조류가 수로와 논으로 이동하면서 급격하게 감소하여 나타났다. 이는 저수지와 논의 유기물 성상이 다름을 보여준다. 영양염류인 총인(TP)의 평균값 변화를 보면 R 0.302 mg/L, C 0.374 mg/L, P 0.384 mg/L로, 저수지에서 수로, 논으로 이동하면서 점차 증가하여 나타났다. 이는 농업용저수지에서 수로, 논으로 관개용수가 이동하면서 오염수 유입 또는 비료 등의 투입이 이루어진 결과로 판단된다. 이와 같이, 농업용저수지의 수질이 논에 그대로 유지되어 유입되지 않고 공급단계에 따라 변화하고 있으므로 항목별 수질 변화 특성을 이해한 후 농업용수 수질관리가 이루어 져야 할 것이다.

• Journal of Biosystems Engineering
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• 제42권1호
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• pp.1-11
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• 2017

Purpose: Methods: Three-dimensional CFD modeling was conducted to analyze the flow structure and discharge flow rate corresponding to the variation in the geometry of the flow channel in a microtube. Additionally, experiments were carried out, and the discharge flow rate was measured at various inlet pressures and inclination angles of the microtube. Results: The quantitative data of velocity distribution and discharge flow rate were obtained. As the width and length of the microtip increased, the discharge flow rate decreased significantly because of the increase in the loss of pressure along the microtube. As the depth of the microtip increased, the flow rate also increased because of the reduction in the flow resistance. However, in this analysis, the variation in the angle of the microtip did not influence the flow rate. From the experimental results, it was observed that the flow rate increased linearly with the increase in the inlet pressure, and the effects of the inclination angle were not clearly observed in those test cases. The values of the flow rate obtained from the experiments were significantly lower than that obtained from the CFD analysis. This is because of the distortion of the shape of the flow path inside the microtube during the fabrication process. The distortion of the flow path might decrease the flow cross-sectional area, and it would increase the flow resistance inside the microtube. The variation in the flow rate corresponding to the variation in the inlet pressure showed similar trends. Conclusions: Therefore, the results of the numerical analysis obtained from this study can be efficiently utilized for optimizing the shape of the microtip inside a microtube.

• 한국농공학회논문집
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• 제60권1호
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• pp.31-36
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• 2018

A rainwater harvesting device was developed for runoff flow harvesting in a small stream or channel and its performance was evaluated in small fields. The rainwater harvesting device has slits on its side of cylindrical volume in 15 cm diameter and 70 cm length, which is designed to increase its water flow harvesting capacity. The maximum collectable water quantity was about 0.0022 ton/sec (130 L/min). Rainwater harvesting device were installed in two locations (P1, P2). P1 is a point for rainfall runoff flow harvesting. P2 is a point for ordinary flow harvesting. During this study, total rainfall depth was 334.5 mm. Runoff of 1,722 ton and 7,984 ton occurred in P1 and P2, and 273 ton and 125 ton were collected by this rainwater harvesting device. Harvesting efficiency was calculated as 15.85 % and 1.57 % in P1 and P2. Clogging of screen filter media in the cylinder due to soil and suspended solids has lowered the harvesting efficiency. However, it was possible to harvest 30 ton/month of rainwater harvesting and it is expected that it will help to solve short-term water shortage.