• 한국농공학회논문집
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• 제47권3호
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• pp.15-25
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• 2005

Ninety tow percent of over 1,800 gate controlled dams in Korea are classified as small dams. The primary purpose of these small dams is to supply irrigation water. Therefore, while large dams can store as much as 80 percent of precipitation and thus are efficient to control flood, small dams are often lack of flood control function resulting in increased susceptibility drought and flood events. The purpose of this study is to develope a storage management model for irrigation dams occupying the largest portion of small dams. The proposed Storage Management Model (STMM) can be applied to the Seongju dam for efficient management. Besides, the operation standard is capable of analyzing additional available water, considering water demand and supply conditions of watershed realistically. And the model can improve the flood control capacity and water utilization efficiency by the flexible operation of storage space. Consequently, if the small dams are managed by the proposed Storage management model, it is possible to maximize water resources securance and minimize drought and flood damages.

• 한국대기환경학회지
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• 제31권4호
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• pp.385-395
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• 2015

This study evaluated indoor environmental characteristics in an office room equipped both with ventilation window system and central cooling system. Fresh air is supplied only by the central cooling system whereas indoor air is discharged outside through both ceiling diffuser and a ventilation window system. Numerical study is conducted by changing the volumetric flow rates of exhaust ports of each system. For estimating the performance of this coupled system, $CO_2$ concentration and Predicted Mean Vote (PMV) were calculated using Computational Fluid Dynamics (CFD) simulation. The more the ceiling diffuser exhausts indoor air, the more the $CO_2$ concentration decreases. However, when the ventilation window system exhausts more indoor air, thermal comfort level gets improved in the office room with cooling system. Therefore, when the ventilation window system is operated, the coupled operation with central cooling system should be considered for enhancing indoor air quality and thermal comfort, together.

• 한국직업건강간호학회지
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• 제29권4호
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• pp.247-253
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• 2020

Purpose: Multimorbidity is defined as the coexistence of multiple chronic diseases within a person. This study explores the burden of multimorbidity in the working population, focusing on the recent increase in elderly workers in Korea. Methods: We summarized past empirical or theoretical literature. Results: Previous literature shows that about 80% of the elderly are multimorbid, and more than half of people with chronic disease have two or more chronic conditions. Multimorbidity is a common phenomenon in the elderly working population. However, little is known about its prevalence, the factors related to its unequal distribution among workers, and its effects on health outcome measures such as mortality, medical use, and employment decisions. Conclusion: This study asks researchers to focus on a subgroup analysis employing data on the working population. Health professionals need to develop clinical guidelines for multimorbid patients. As multimorbidity is a major health concern in the working elderly, prevention and control should be promoted in the workplace.

• Architectural research
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• 제19권4호
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• pp.95-99
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• 2017

Recently, it is becoming increasingly difficult to ignore carbon emission implication of building operations due to the significant rate of energy usage in buildings. In the building sector, our normal expectation implies that large building floor area induces more greenhouse gas (GHG) emission. In this research, the correlation between building total floor areas and GHG emission was explored by simple linear regression and analyzing the yielded residuals for confirming this seemingly obvious conjecture. By looking at the generated regression lines drawn based on the data sets representing public facilities in Ontario, Canada, we were able to confirm that carbon emission rate shows a proportional increase or decrease depending on the total floor area of buildings as has been implied as a conjecture. Some buildings were found to emit significantly large and small amount of GHG, and we addressed potential reasons why those buildings show the deviation from the confirmed proportional interrelation between a building's total floor area and the amount of GHG emission.

• 한국농공학회논문집
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• 제46권2호
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• pp.15-25
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• 2004

For the effective operation of irrigation reservoirs, a general and systematic policy is suggested to make balance of the conflicting purposes between water conservation and flood control. In this study, the flood effective analysis system was developed through the integration of long-term water budget analysis model, GIS-based HEC-HMS model and HEC-RAS model. The system structure consists of long-term water budget model using modified TANK theory, flood runoff and flood effects analysis model using HEC-GeoHMS, HEC-HMS and HEC-RAS models. The flood effects analysis system simulated the flood runoff from the upstream, downstream flood and long-term runoff of the watershed using the observed data collected from 1998 to 2002 of Seongju dam. The simulated results were reasonably good compared with the observed data. The optimal management method of the reservoir during the whole season is suggested in this study, and the flood analysis system can be a useful tool to evaluate a reservoir operation quantitatively for the mitigation of flood damages of reservoir basin.

• 한국분무공학회지
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• 제22권2호
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• pp.62-68
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• 2017

It is important to study on the combustion instability to develop liquid rocket engines for preventing lower combustion efficiency and destruction of combustion chamber. There are many researches on simplex injector with liquid pulsation to solve this problem. In real rocket engine system, however, they use coaxial injectors. Therefore, research on coaxial injector with liquid pulsation is essential. In this study, we investigate dynamic characteristics of gas centered swirl coaxial injector varying tangential inlet diameter. A mechanical pulsator was used to generate an excitation in the liquid flow, and the response characteristics of the injector were confirmed. As tangential inlet diameter increased, mass flow rates increased and spray angle decreased. As tangential inlet diamter decreased, gain decreased because the pressure fluctuation in the injector manifold rarely passed through the inlet. Additionally, it was confirmed that a sufficiently small tangential inlet served as a damper.

• 한국농공학회논문집
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• 제46권1호
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• pp.3-13
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• 2004

For optimal irrigation reservoir operation during flood and normal period, a general and systematic policy is suggested to make balance of the conflicting purposes between water conservation and flood control. We developed Open Water Management Program (OWMP) with an open architecture to deal with newly arising upgrade problems for optimal management of irrigation reservoir. And we evaluated the applicability of OWMP to estimate daily runoff from an agricultural watershed including irrigation reservoirs, and analyzed behaviour of irrigation reservoirs as irrigation water requirements considering frequency analysis of reservoir storage and frequency analysis water requirements for effective management of reservoir. When we executed OWMP with data produced from an experimental field, IHP basins, the mean relative errors of application of daily runoff and irrigation water requirement were less than 5％. We also applied OWMP to a Seongju irrigation reservoir to simulate daily runoff, storage and water requirement from 1998 to 2002, and the mean model efficiency between measured and simulated value was 0.76. Our results based on the magnitude of relative errors and model efficiency of the model simulation indicate that the OWMP can be a tool nicely adapted to the effective water management of irrigation reservoir for beneficial water use and flood disaster management.

• 농촌계획
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• 제20권4호
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• pp.45-54
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• 2014

The main purpose of this study is to provide the back-from-city farmers with the information about the melon cultivation technology by surveying 268 farm houses in the major melon producing districts such as Seongju and Chilgok. For the purpose, this study classifies the essential technologies that the melon experts think as most important into 6 categories: size of plastic film house, covering film, varieties of oriental melon, lagging cover, ventilation method and ways to reduce repeated-cultivation damage. The result of the study shows that the back-from-city farmers should consider the following items when they choose to cultivate oriental melons. For the size of plastic film house, the ventilation method and the covering film of plastic film house, it is better to choose the latest technology. Even though it may require larger initial investment, the latest technology can increase the production and lower the cost. In case of variety, it is better to choose popular or the most widely grown ones rather than the new ones. The lagging cover should be selected in consideration of climate conditions such as average temperature and humidity, transplant time and harvest time of the farming region.

• 한국균학회지
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• 제26권3호통권86호
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• pp.399-402
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• 1998

Zoophthora radicans를 생물적 방제에 이용하기 위하며 각국에서는 우수 균주 탐색에 많은 노력을 하고 있지만 국내에서는 이 균이 보고된 바 없다. 본 연구자들은 이 균을 1998년 3월경 경북 성주군 쑥갓 재배 온실내의 복숭아 혹진딧물에서 발견하였다. 이에 국내에서 처음으로 Z. radicans를 보고하며, 무성세대의 형태적 특징을 기재한다. 이 균의 가장 중요한 분류학적 특징은 2차포자가 1차포자로부터 만들어진 긴 분생자병에서 형성되는 것이었다.

• 한국농공학회논문집
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• 제63권6호
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• pp.89-100
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• 2021

The conservation of stream habitats has been gaining more public attention and fish habitat suitability index (HSI) is an important measure for ecological stream habitat assessment. The fish habitat preference is affected not only by physical stream conditions but also by water quality of which HSI was not available due to the lack of field data. The purpose of this study is to estimate the HSI of Zacco platypus for water quality parameters of water temperature, dissolved oxygen (DO), and biochemical oxygen demand (BOD) using the water environment monitoring data provided by the Ministry of Environment (ME). Fish population data merged with water quality were constructed by spatio-temporal matching of nationwide water quality monitoring data with bio-monitoring data of the ME. Two types of the HSI were calculated by the Instream Flow and Aquatic Systems Group (IFASG) method and probability distribution (Weibull) fitting for the four major river basins. Both the HSIs by the IFASG and Weibull fitting appeared to represent the overall distribution and magnitude of fish population and this can be used in stream fish habitat evaluation considering water quality.