• Journal of Korea Water Resources Association
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• v.41 no.12
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• pp.1173-1185
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• 2008

The design methods of the road surface drainage facilities were compared for the improvement of design method. We have developed four computational design models classified by the methods to determine the duration of design rainfall and to analyze the flow of a linear drainage channel. The critical duration was determined by assuming the critical duration to be 10 minutes or by finding the duration of design storm being similar to the travel time of flow by trial and error. The flow of a linear drainage channel was analyzed as the uniform flow or the varied flow. The design models were applied to the artificial road surface drainage facilities with various channel slopes and road shoulder slopes. If the rainfall intensity of the 10 minutes duration was applied, the outlet spacing obtained from the design based on the varied flow analysis was larger than the uniform flow analysis only when the channel slope and the road shoulder slope was small. On the other hands, if the duration of design rainfall was determined by calculating the travel time, the varied flow analysis brought about larger outlet spacing than the uniform analysis for all conditions. However, the model of the critical duration concept and the varied flow analysis resulted in smaller outlet spacing than the current design method employing the rainfall of 10 minutes duration and the uniform flow analysis.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.113-116
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• 2005

Recently the existing environment-friendly method is used in irrigation and drainage canal. So, it is necessary that environment-friendly canal method which is stable and quality. Environment-friendly manufactures which were reflected demand characteristic of drainage and irrigation canal were developed. This study is focused on quality, stability for agricultural district development. According to the results, this method has quaility and economical efficiency, stability and natural characteristic, and will contribute to environment-friendly canal construction.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.108-113
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• 2000

A field study was performed to investigate the effect of water saving irrigation method on water use efficiency and rice yield. The field plot was 40a (40 ${\times}$ 100m) in size and located at Buryangmyun, Kimjae city, Chonbuk province. Field measurements were made during the growing seasons, May to September of the year 1998 and 1990. Irrigation water volume, drainage water volume, rainfall and ponding depth were measured. Irrigation water management practice employed was such that to keep the ponding depth about 3 to 4cm by intermittent irrigation with drying the soil surface until hair cracks emerge before the next irrigation. The amounts of water volume irrigated and drained were measured by pipe flow meter and ponding depth was observed by using a partly buried 120mm diameter PVC pipe. The results showed that the irrigation water depths, the rainfalls, and the drainage depths were 379mm, 458mm, and 448mm in 1988, and 274mm, 819mm, and 736mm in 1990, respectively. The average yield was 590kg per 10a. The water saving irrigation method saved irrigation water by about 20% with higher yield compared with the traditional method.

• Korean Journal of Bronchoesophagology
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• v.15 no.2
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• pp.64-70
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• 2009

Descending necrotizing mediastinitis(DNM) can occur as a complication of oropharyngeal and cervical infections that spread to the mediastinum via the cervical spaces. Delayed diagnosis and inadequate mediastinal drainage through a cervical or minor thoracic approach are the primary causes of a high mortality rate. Therefore, We emphasize that aggressive and emergent mediastinal drainage by surgical approach is most important method of DNM treatment. We studied 5cases diagnosed as DNM from 2005 through 2007. All patients underwent emergent surgical drainage of deep neck infection combined with mediastinal drainage through a thoracic approach. Primary oropharyngeal infection lead to DNM in four cases(80%) and odontogenic abscess in one case(20%). The outcomes were favorable 5patients. Overall mortality rate was 0%. The time interval from diagnosis based on manifestation of initial symptoms(oral or pharyngolaryngeal area) to surgical intervention was $7.4{\pm}4.2$days. One patient required reoperation due to remnant mediastinal abscess and pericardial effusion. Early diagnosis and emergent combined drainage with neck and chest incisions, together with broad spectrum intravenous antibiotics, should be considered standard care for this disease. And intensive postoperative care which it is continuous mediastinal irrigation and antibiotics use can significantly reduce the mortality rate.

• Fire Science and Engineering
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• v.21 no.3
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• pp.69-77
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• 2007

Our country automatic wet pipe sprinkler system of hydraulically designed system has not deviated from the pipe regulation process, therefore we face limitations when using an independent method to hydraulically designed system. Therefore. after reviewing a developed country's methods using the drainage-density concept, we found it necessary for our country to introduce the drainage-density concept. Currently, under the National Fire Safety Codes(NFSC), this does not solve the problem and the limitation of hydraulically designed system because different problems arise depending on where the head was installed. To make improvements, first, such as the developed country, overcome the difference by introducing the drainage-density concept to determine the amount of drainage. Second, by using diverse head caliber and decreasing the limits on the amounts of distribution, we can expect a leveling off of the drainage density. Third, using the increase of hydraulically designed system through the application of the rule to hydraulically designed system, finally, development to performance based fire protection design.

• Journal of the Korean GEO-environmental Society
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• v.12 no.11
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• pp.59-64
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• 2011

Clogging in drainage pipe is one of the important problems, so it needs a remedy urgently. Recently, scale in drainage pipe is removed by water jet cleaning and other treatment. But these treatments need much cost and regular management. The principal component of scale in drainage pipe is $CaCO_{3}$. It was observed the setting of $CaCO_{3}$ by some kind of analysis such as SEM, XRD, visual and weight measuring analysis to solve these problems and prevent setting formation in drainage pipe. As a result, in case of magnetic, particle shape of $CaCO_{3}$ is changed Aragonite from Calcite. Also in case of Quantum Stick, the amount of scale is reduced by expert inspector's result. As a whole, Magnetic treatment and Quantum Stick have the effect for protecting of scale precipitation.

• Journal of Korea Water Resources Association
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• v.40 no.2 s.175
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• pp.113-124
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• 2007

Low flow is a minimum flow discharging during a dry season in a unregulated stream which can be shared by nature and human being. It is also a standard flow that determines a diversion requirement by evaluating water supply ability of streamflow in the aspect of water use. Low flow indices are used as average low flow and 1-day 10-year low flow in Korea and Japan and as 7-day 10-year low flow in the United States of America and the United Kingdom. In this research, these three indices were compared by the data observed and generated. Although daily records are needed to calculate the low flow, gauging stations are limited and records of the dry season are insufficient in Korea. Drainage-area ratio method is mainly used in Korea to estimate the low flow. This research shows the guideline when the drainage-area ratio method, the regional regression method, and the baseflow correlation method to calculate the low flow of ungauged basins are applied and recommends low flow estimation method suitable to Korea.

• Horticultural Science & Technology
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• v.28 no.3
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• pp.409-414
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• 2010

The first drainage time in a day was controlled for precise irrigation management with low consumption of nutrient solution in tomato perlite bag culture system by measuring water level of drained water in drainage catchment part. This method automatically adjusted the irrigation time under any condition of light, temperature and humidity, resulting in stable water content in substrates. However, it was difficult to keep the time consistent as they were set. It drained with the deviation of 20 min in the treatment in which the first drainage time was set at 10:00 and 50 min in the treatment set at 10:30. The first drainage time was not constant, but the drain occurred stably before noon in the treatment of which irrigation frequency was longer than 30 min. The drainage ratio was better balanced in all the treatments using drainage level sensors than the treatment using time clock for irrigation control. High water and fertilizer efficiencies were obtained. Although the growth, total yield and sugar content were not significantly different between the treatments, fruit weight was higher in the treatments using drainage level sensors than that using timer.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.1
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• pp.33-38
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• 1995

This experiment was conducted to elucidate the effect of the midsummer drainage times on lodging characters, field lodging and yield in direct seeding rice culture in puddled soil. Dongjinbyeo was seeded at May 11 by seeding machine with 4cm of furrow depth and drained, one（50days after seeding DAS）） two （30DAS and 50DAS）, and three times （30DAS, and 50DAS and 60DAS）. The results are as follows. Culm length was shorten and the wall of N3, N4 were thicken as the drain-age times were increased. As the drainage times were increased breaking weights were increased but the lodging index were decreased. Lodging was occurred seriousely at none drainage, but wasn't occurred two or three times drainage. Yield was higher at 1~2 times drainage compared with none and three times drainage. Therefore, two times midsummer drainage is recommend-able water management method for direct seeding rice culture in puddled soil.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.119-123
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• 2010

Causes of the levee collapse are directly or indirectly associated with geotechnical engineering as well as hydraulics. In this paper, literature survey and analysis were conducted to present the alternatives in geotechnical engineering issues for rational levee design. The alternatives include the reasonable river-bed soil utilization and precautions of numerical analysis and slope stability analysis, disruption type and improvement method of drainage facility.