• 한국산업융합학회 논문집
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• 제10권4호
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• pp.275-283
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• 2007

This study aims at the calculation of a variation of flow characteristics of main channel for tributary inflow in river junction. So this study was analyzed the variation of flow depth and velocity in main channel for a change of inflow degree. For this purpose, FLDWAV model are carried out for variations of $30^{\circ}$, $60^{\circ}$ and $90^{\circ}$ tributary inflow at junction. Results show that velocity ratio(V1/V3) increases and flow depth ratio(H1/H3) decreases for discharge ratio(Q1/Q3) of upstream and downstream when degree increases in junction. And FLDWAV model was applied at a real river junctions. Selected area is a junction of Gumho river and Sin stream. Results show that pattern is similar to a virtual channel.

• 무역상무연구
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• 제59권
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• pp.181-205
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• 2013

This study has analyzed the international trade flow of medical devices in Korea, China, and U.S. more theoretically and systematically through a mutual connection of the medical device export structure of Korea and the import structure of China and U.S. organically, with an intensity approach on the bilateral international trade flow. Also, it is meaningful to find a solution to boost exports of Korea to China and U.S.. Therefore in this study, we recognize the importance of the medical device market in China and U.S., which is the main competition for Korea and its market, and look into the trade situation of these three countries. We also look into the relative market stream and the trade intensity of the main medical devices in Korea, China and U.S., and seek measures for the steady growth of the medical device market in these three countries.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.362-365
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• 2004

'Coil' occupies a much important position in delivering driving force of optical pick-up actuators. Up to now the main stream has been a winding coil type actuator, but actuators using FP-Coil(Fine Pattern Coil) have been considered for the more compacted and simple manufacturing process and have variously spreaded the application fields by product. We have tried to design actuators using PCB-Coil(Printed Circuit Board Coil) which has benefits in terms of price and manufacturing process. Especially this research has two main things those are to reduce the vibration of sub-resonance and to assure the do sensitivity in the performance of asymmetric optical pick-up actuator with PCB-Coil.

• Child Health Nursing Research
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• 제24권2호
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• pp.166-177
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• 2018

Purpose: The purpose of this study was to explore and describe the meaning and essence of experiences of stress in mothers of preschoolers with atopic dermatitis. Methods: This study employed a qualitative research design. Seven mothers of preschoolers with atopic dermatitis were interviewed and the data were analyzed using Giorgi's phenomenological method. Results: Five main themes and 12 theme clusters emerged. The 5 main themes were 1) the mother's enduring heartache from the conflict that arise among family members, 2) the complete loss of daily happiness, 3) the steady stream of emotional fluctuations, 4) struggling to bear the heavy financial burden, and, 5) a life of hope accompanied by stress. Conclusion: The results of this study provide an in-depth understanding of stress among mothers of preschoolers with atopic dermatitis. These results can be used in the development of nursing interventions to provide psychological and emotional support for mothers and family members.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2007년도 학술발표회 논문집
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• pp.1464-1468
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• 2007

The restoration project of Cheonggyecheon was conducted to creates the refreshing water-friendly environment in the downtown Seoul. It already have passed almost 2 years after restoration. This project changed environment of Cheonggyecheon dramatically, so historic hydrological data became useless. There are not so many hydrological data to manage and control this newly restored urban stream. The main purpose of this study is collecting and analysing the hydrological data of Cheonggyecheon. At first, we analysed the mechanism of Cheonggyecheon discharge using the sewage design maps and some GIS data. We also monitored the water levels and discharges of 5 main points of Cheonggyecheon. Rating curves of these 5 points were derived. There were 249 blocks of water gates which were located at both sides of bank. We also monitored the behaviors of these water gates. Through the these monitorings, some equations were derived to give useful information to the manager of Cheonggyecheon.

• Journal of Information Science Theory and Practice
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• 제5권1호
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• pp.65-84
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• 2017

Three most popular information services, Periscope, Ustream, and YouNow, vicarious for all Social Live-Streaming Services (SLSSs), are investigated to analyze their streamers' motivations and the user-generated content. Additionally, we collected demographic data (gender and age). More than 7,500 streams by users from the U.S., Germany, and Japan were observed. Main streamer motivations on SLSSs are boredom, socializing, the need to reach a specific group, the need to communicate, and fun. Important content categories on all three SLSSs are chatting, sharing information, 24/7, and 'slice of life.' We were able to identify differences between users from the U.S., Germany, and Japan as well as between the users of Periscope, Ustream, and YouNow. The main motive to stream in the U.S. is to reach a specific group, while in Japan it is socializing, and in Germany boredom. The top content category for both, YouNow as well as Periscope, is to chat; on Ustream it is 24/7 (i.e., webcams).

• Water Engineering Research
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• 제2권4호
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• pp.219-229
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• 2001

Synthetic unit hydrograph equations for rainfall run-off characteristics analysis and estimation of design flood have long and quite frequently been presented, the Snyder and SCS synthetic unit hydrograph. The major inputs to the Snyder and SCS synthetic unit hydrograph are lag time and peak coefficient. In this study, the methods for estimating lag time and peak coefficient for small watersheds proposed by Zhao and McEnroe(1999) were applied to the Kum river basin in Korea. We investigated lag times of relatively small watersheds in the Kum river basin in Korea. For this investigation the recent rainfall and stream flow data for 10 relatively small watersheds with drainage areas ranging from 134 to 902 square kilometers were gathered and used. 250 flood flow events were identified along the way, and the lag time for the flood events was determined by using the rainfall and stream flow data. Lag time is closely related with the basin characteristics of a given drainage area such as channel length, channel slope, and drainage area. A regression analysis was conducted to relate lag time to the watershed characteristics. The resulting regression model is as shown below: ※ see full text (equations) In the model, Tlag is the lag time in hours, Lc is the length of the main river in kilometers and Se is the equivalent channel slope of the main channel. The coefficient of determinations (r$^2$)expressed in the regression equation is 0.846. The peak coefficient is not correlated significantly with any of the watershed characteristics. We recommend a peak coefficient of 0.60 as input to the Snyder unit-hydrograph model for the ungauged Kum river watersheds

• 자원환경지질
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• 제45권3호
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• pp.265-276
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• 2012

용화광산의 광미와 침출수에 대한 분석을 실시하여 광미로부터 부과될 수 있는 성분을 예측하고, 침출수가 주변하천으로 유입될 때 오염물질의 거리에 따른 변화를 측정하였다. 하천수의 거리에 따른 변화는 갱내수와 침출수가 유출되는 지점에는 대체로 높게 나타나고 하류로 갈수록 이온의 농도는 급격히 낮아진다. 이는 침출수에 비해 훨씬 유량이 많은 비오염하천수에 의한 희석효과 때문이다. 광미는 붉은색과 노란색으로 구분되며 붉은색 광미의 주 구성광물은 석영, 일라이트, 플럼보자로사이트와 약간의 섬아연석이며 노란색 광미는 백운모, 석영, 플럼보자로사이트(Plumbojarosite) 그리고 소량의 황동석(Chalcopyrite)과 섬아연석(Sphalerite)을 포함하고 있다. 침출수에서 높은 값을 나타내는 Pb, Zn 등은 광미에 포함된 플럼보자로사이트와 섬아연석의 용해작용에 의한 것으로 하천수의 오염에 주 원인으로 작용하고 있다.

• 한국물환경학회지
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• 제28권1호
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• pp.10-17
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• 2012

The middle and lower reaches of the Kum River system become stagnant in dry seasons with florishing of phytoplankton. In this study primary productivity of phytoplankton were measured by the C-14 uptake method and the P-I model method at seven main stream sites of the Kum River from the Daechung Dam outet to the river mouth. Nutrients (TN, TP, DIP, TIN) concentrations were measured in the mainstream and tributaries and compared with the variation of assimilation number. The range of primary productivity was $40{\sim}4,558mgC{\cdot}m^{-2}{\cdot}day^{-1}$ and it was higher than those of lentic ecosystems in Korea. Average TN and TP were $4.1mgN{\cdot}L^{-1}$, $70.6mgP{\cdot}m^{-3}$, respectively. Tributaries showed higher nutrient concentrations than the main stream. After two major tributaries merged with the discharging water of the Daechung Dam phyotplankton biomass and productivity increased drastically and remained at the similar eutrophic level through the downstream reach to the river mouth. Both dissolved phosphorus and nitrogen concentrations showed positive correlation with assimilation number of phytoplankton. In conclusion phytoplankton productivity is at the level of eutrophic water and it was higher than usual lentic habitats. Nutrient concentrations are critical factors in controlling productivity in the lower reach of the Kum River.

• 환경생물
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• 제19권4호
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• pp.239-247
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• 2001

1994년 6월부터 8월까지 금호강 본류의 유수변 초본식생을 식물사회학적으로 조사하였으며, 수질환경과 관련된 식생의 분포특성을 밝혔다. 금호강 본류의 하변식생은 여뀌-미꾸리낚시군락(Persicaria sieboldi-Persicaria hydropiper community), 고마리군락(Persicaria thunbergii community), 물봉선군락(Impatiens textori community), 줄군락(Zizania latifolia community), 갈대군락(Phragmites communis community), 물피군락(Echinochloa crus-galli var. oryzicola community)의 6군락으로 분류되어있다. 수질오염의 정도를 나타내는 BOD와 COD는 상류에서 각각 0.9ppm과 1.6ppm을 보였으며, 하류로 갈수록 증가하여 최하류에서는 각각 15.9ppm과 24.8ppm으로 나타났다. 하변식생의 분포유형은 최상류에 물봉선군락, 상류에서 중상류까지 여뀌-미꾸리낚시군락, 상류에서 중류까지 고마리군락, 중류에서 중하류까지 줄군락, 중하류에서 하류까지는 갈대군락 및 물피군락이 주로 우점하였다. 특히, 여뀌-미꾸리낚시군락과 고마리군락은 수환경의 생물지표로 이용될 수 있을 것으로 판단되었다.