• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.832-836
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• 2009

공유수면을 간척 또는 매립하여 국토를 확장하여 산업화 도시화에 따른 토지수요 용도변경에 대처하여 국가발전의 균형을 유지하는 목적으로 수행하는 간척사업 시설중 중요한 시설인 배수갑문은 외수(해수)의 차단 및 내수배제를 통한 침수피해 경감의 역할을 수행하고 있다. '02년 태풍 "루사" 등 수공구조물의 설계빈도를 초과하는 폭우 발생으로 인한 홍수피해가 발생하고 배수갑문 설계시보다 유입홍수량이 증가하여 홍수시 수위가 계획홍수위 이상으로 형성되는 경우가 많아 이를 해결하기 위하여 배수갑문의 확장사업이 실시되고 있다. 그 첫 번째 사업으로 아산만방조제 배수갑문의 확장을 실시하였다. 아산만방조재 신설 배수갑문의 위치가 연약지반으로 형성되어 있어 신설 배수갑문을 통한 방류시 고속의 수류로 인한 바다측 물받이공 하류부의 세굴이 발생할 가능성이 크며, 이로 인한 배수갑문의 붕괴 우려가 있다. 그러므로 이를 방지하기 위하여 배수갑문 하류에 정수지형 물받이공을 설치하여 고속으로 방류되는 방류수의 유속을 저감시켜 세굴의 발생이 최소화하여 안정성이 확보되도록 하였다. 정수지형 물받이공의 효과 및 안정성을 검증하기 위하여 3차원 수치해석 FLOW-3D모형을 적용하여 수평물받이공과 정수지형 물받이공의 유속차이를 비교분석하였다. 분석한 결과 정수지 말단부에서 정수지 시점부와 비교하여 유속감소는 최대 약 49%, 평균 약 39%의 유속 감세효과를 나타내는 것으로 나타나 정수지형 물받이공을 통한 세굴 감소효과로 아산만방조제 배수갑문의 세굴에 의한 안정성은 확보되는 것으로 나타났다.

• Journal of Animal Environmental Science
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• v.9 no.1
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• pp.9-18
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• 2003

Most of broiler houses in Korea have the trouble of environmental control such as suitability, stability, and uniformity of internal climate, resulting in serious stress on chickens. Accordingly, it is very urgent to develop optimum designs of naturally and mechanically ventilated broiler houses for Korean climate. In this study, the internal climates such as air temperature, humidity, dust, ammonia gas, and air velocity were measured at a naturally ventilated broiler house. The data were collected during summer season including local weather data. It was found that the difference between measured and optimum air temperatures was $14.0^{\circ}C$ in maximum during the summer time. The daily maximum range of internal averaged air temperature was found $10.5^{\circ}C$ while the uniformity was $5.2^{\circ}C$ in maximum. The maximum, average, and minimum internal averaged relative humidity were 89.3%, 73.7%, and 49.2%, respectively while locally measured were 95.1% and 47.2%, respectively in maximum and minimum. Considering Temperature-humidity index, during summer season, over 97% of totally rearing period was shown that counter plan is needed for thermal stress while it was very dangerous situation for 22% of the rearing period. The ammonia gas and dust concentrations were seriously affected by the broilers activity, growth level, and relative humidity.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.309-309
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• 2021

댐 설계 시 가능최대강수량(probable maximum precipitation, PMP)으로 인한 홍수량인 가능최대홍수량(probable maximum flood, PMF)이 고려되며, 이를 산정하기 위해서는 단위도가 필요하다. 즉, PMF는 PMP를 입력으로 하여 단위도를 이용한 강우-유출 해석을 통해 얻어진다. 따라서, 동일한 PMP가 고려되더라도 적용되는 단위도에 따라 산정되는 PMF는 달라진다. PMP가 발생하는 상황에서는 평균적인 상황에 비해 단위도의 반응이 보다 빠르고 강해진다(한국개발연구원, 2007; 한국수자원공사, 2008; Kjedsen et al., 2016). 국내의 경우, 아직까지 PMF 산정을 위한 단위도에 대한 명확한 지침은 존재하지 않는다. 댐설계기준해설(국토해양부, 2011)에서는 유역의 평균단위도로 PMF를 추정할 경우 실제보다 낮은 결과치가 도출되는 문제가 있을 수 있다는 점을 경고하는 수준에 그치고 있다. 이에 본 연구에서는 유속 정보를 기반으로 PMF 산정을 위한 단위도를 결정해 보고, 이를 통해 대표단위도로부터 PMF 산정을 위한 단위도를 결정하기 위한 수정 방법을 제안하였다. 추가적으로 이러한 수정단위도를 적용하여, 기존 국내 기준 적용 결과 및 확률 강우량을 통해 산정되는 빈도홍수량과의 비교를 수행하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.3 no.1
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• pp.38-44
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• 1991

A simple box model was applied to the sedimentation of fine-grained sediments in a rectangular basin. Using the model explanation of the net depositional process of One-grained sediments in a small tide-dominated rocky embayment was possible by a careful evaluation of coefficients for erosion and deposition. For a basin with an inlet through which the exchange of suspended sediments occurs between open sea. the model shows that the time-averaged concentration of suspended sediments for a tidal cycle reaches a steady state initial abrupt change in concentration. During a tidal cycle deposition of sediments seems to occur when the magnitude of tidal currents is substantially low near the slack waters. Resuspension and erosion of bottom sediments take place near the peak of tidal currents. For a depositional basin. Gamagyang Bay, the duration and the maximum rate of deposition appear to be longer and higher than those of erosion. which accounts for the net deposition of fine-grained sediments. The time-averaged concentration of suspended sediment in the basin is slightly lower than that of the open water due to the net deposition. The instantaneous concentration of suspended sediments showed the maximum value about an hour before high water and the minimum about an hour after low water.

• Tuberculosis and Respiratory Diseases
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• v.44 no.2
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• pp.290-297
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• 1997

Background : Despite remarkable progress of understanding the pathophysiology and therapy of bronchial asthma, asthma morbidity and mortality are on the rise. Also hospitalization and attending rates of emergency department for asthma have been increasing gradually. We analyzed clinical characteristics and prognosis of patients who visited emergency room due to asthma attack in order to define clinical characteristics of these group of patients. Method : We reviewed 105 adult asthmatic patients who attended emergency department of Korea University Hospital between August 1995 and July 1996, retrospectively. Results : 103 patients(56 female, 47 males, mean age : 48.6 years) attended-68 self referral, 18 practitioner referral and 17 OPD transfer- and 86 patients(83.5%) were admitted. Attending emergncy department was clearly more frequent in December(13.6%) and May(12.6%). Time lag between onset of asthmatic attack and arrival at the hospital was $14.2{\pm}15.5$ hour and initial peak expiratory flow rate was $166.7{\pm}68.3L/min$.(43.3% predicted) The commonest cause for visiting emergency room was aggravation of asthma due to upper respiratory tract infection in mild asthmatics. About half of them had history of previous ER visits. Their prognosis was not bad, but after discharge, about half of patients escaped from OPD follow-up. Conclusion : As a group they merit detailed attention and follow up arrangement. Clinician need to monitor and review the treatment plans, the medications, the patient's management technique, and the level of asthma control. For this group, plans for longer term treatment, including asthma education program and adjustment of overall treatment plan should be made.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.98-104
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• 1999

To investigate the relationships between ocean environmental characteristics, the time-series data of temperature and salinity observed at a station near at Hanlim set net in 1995 and 1996 are analyzed, and the results are as follow ; 1. In hanlim set net, the diurnal range of temperature and salinity variation in summer is very large and the amplitude of short-period fluctuation of temperature and salinity is very large. That is, not only the water of the middle and bottom layers (low temperature and high salinity) but also the coalstal water (high temperature and low salinity) appears alternatively depending on the current direction 2. from the result of mooring for 22 days in Hanlim set net, the mean speed and direction of tidal current in neap tide were 9.1 cm/sec and south westward in ebb time, and 11.6 cm/sec and north or northeastward in flood time, respectively. The highest speed of the current was 15cm/sec in ebb time, and 22.6 cm/sec in flood time. The mean speed and direction of tidal current in spring tide were 10.4 cm/sec, and southwestward in ebb time, and 12.3 cm/sec, and north or northestward in flood time, respectively. The highest speed of the current was 19.4 cm/sec in ebb time, and 20 cm/sec in flood time respectively. The mean speed of the current in flood time was larger than that in ebb time. The velocity vector along the major axis of semidiurnal tide ($M_2$) component was 1.5 times larger than that of diurnal tide ($K_1$), The major directions of two compornants were northwestward and east-southeastward and residiual current were 3.25 cm/sec and northwestward-directed. Result of TGPS Buoy tracer for 3 days between Biyang-Do and Chgui-Do showed that the mean speed was 1.6 knot in ebb time and 1.3 knot in flood time. Direction of tidal was southwestward in ebb time and northeastward in flood time respectively. The maximum current speed was 4.8 knot in ebb time and 3.7 knot in flood time respectively. The mean speed and direction of tidal in of offshore were 1.7 knot and northwestward in flood time. The residual current appeared 0.3 knot northeastward.

• Journal of Korea Water Resources Association
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• v.54 no.11
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• pp.903-913
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• 2021

In the flood season, the measurement of the river discharge has many restrictions due to reasons such as budget, manpower, safety, convenience in measurement and so on. In particular, when heavy rain events occur due to typhoons, etc., it is difficult to measure the amount of flood due to the above problems. In order to improve this problem, in this study, a method was developed that can measure the river discharge in a flood season simply and safely in a short time with minimal manpower by combining the functions of a drone and a surface velocity doppler radar. To overcome the mechanical limitations of drones caused by weather issues such as wind and rainfall derived from the measurement of the river discharge using the conventional drone, we developed a drone with P56 grade dustproof and waterproof performance, stable flight capability at a wind speed of up to 36 km/h, and a payload weight of up to 10 kg. Further, to eliminate vibration which is the most important constraint factor in the measurement with a surface velocity doppler radar, a damper plate was developed as a device that combines a drone and a surface velocity Doppler radar. The velocity meter DSVM (Dron and Surface Veloctity Meter using doppler radar) that combines the flight equipment with the velocity meter was produced. The error of ±3.5% occurred as a result of measuring the river discharge using DSVM at the point of Geumsan-gun (Hwangpunggyo) located at Bonghwang stream (the first tributary stream of the Geum River). In addition, when calculating the mean velocity from the measured surface velocity, the measurement was performed using ADCP simultaneously to improve accuracy, and the mean velocity conversion factor (0.92) was calculated by comparing the mean velocity. In this study, the discharge measured by combining a drone and a surface velocity meter was compared with the discharge measured using ADCP and floats, so that the application and utility of DSVM was confirmed.

• Journal of Animal Science and Technology
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• v.46 no.4
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• pp.517-524
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• 2004

The objective of this study was to investigate the environmental effects on duration time of milk flow, peak milk flow, and average milk flow in teats, and to estimate their relationships with milk yields in morning and evening milking, and to provide fimdamental information for the further study on their relationships with clinical mastitis and somatic cell in milk. A total of 6,768 milking records were studied in 72 Holstein cows. The influences of season, parity, lactation month, and milking interval on characteristics of milk flow considering in linear model were significant(p<.05). Duration of milk flow was longest at milking in fall, past first parity and second month of lactation, and with milking interval over than 13.5hrs. Average milk flow rate and peak milk flow rate were highest at milking in summer, past first parity and 8${\sim}$10 months of lactation, and with milking interval over than 13.5hrs. Milk flow rate was positively correlated to milk yield, and negatively correlated to the duration of milk flow. However duration milk flow was positively correlated to the milk yield with high level of correlation coefficient(+.60). For the establishment of optimum selection criteria on these traits, other aspects such as the udder health, disease and respective economic weights of milk flow characteristics in this study must be considered to develop the indices.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.1100-1109
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• 2022

Herein, a case study was conducted on the bilge pumping performance of a 24,000TEU class container ship with an overall length of 400m. Although the bilge system of the 24,000TEU class container ship was designed in accordance with the rule requirements of the Classification Society, the bilge system did not satisfy the 2 m/s requirements of SOLAS Reg.II-1/35-1 under the rated flow rate and maximum flow rate conditions of the bilge pump installed in the ship. In particular, assumptions were made that No.1 ~ No.4 cargo holds were flooded and filled entirely by sea water and the evaluation of bilge pumping performance had been performed for No.1 ~ No.4 cargo holds. According to the evaulation results of the, the mean water velocity at the main bilge pipe for No.2, No.3, and No.4 cargo holds did not meet the 2 m/s criterion. To resolve this problem, in this study, the branch bilge pipe in each cargo hold was changed from 150A to 200A and the mean water velocity at the main bilge pipe for No.2, No.3, and No.4 was calculated as 2.479m/s, 2.476m/s, and 2.459m/s, respectively.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.434-437
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• 2004

본 반층벽체 적용지역의 경우, 침출수의 영향으로 암모니아성 질소의 농도가 최대 29.12mg/L까지 검출되고 있으며 반응물질은 암모니아성 질소제거에 적합한 제올라이트를 선정하였다. 투수성 및 다짐강도를 고려하여 왕사와 50:50의 비율로 혼합, 적용하였으며 지하수 평균유속은 0.0864m/d이고 평균지하수위는 원지반 기준 - 4.0m의 분포를 나타내었다. 지질조사 결과, 적용구간의 지질구조는 매립층, 풍화토, 풍차암, 연암의 순서로 분포하고 있으며, 반응벽체의 설계깊이는 현장 시추조사 결과를 바탕으로 지하수의 Under-pass를 방지하기 위하여 연암층 50cm까지 관입시키도록 설계하였다. 최종적으로 선정된 반응벽체의 규모는 35m(길이) $\times$ 1.2m(두께) $\times$ 8.5 ～ 9.42m(구간별 깊이)로 설계에 반영되었다. 현재, 지하수감시정을 이용한 모니터링 결과, 상부지하수 감시정에서의 오염원은 우기의 영향으로 간헐적으로 발생하고 있으나 하부 지하수 감시정에서의 암모니아성 질소농도는 불검출 되거나 0.5 mg/L 이하로 유지되고 있다.