• Korean Journal of Psychosomatic Medicine
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• v.15 no.2
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• pp.65-72
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• 2007

Fatigue is a significant problem in health care. The relationship between chronic fatigue and psychiatric disorders has generated significant interest in recent years. Increased rates of psychiatric disorder among individuals with chronic fatigue have been reported. Fatigue may be defined as physical and/or mental weariness resulting from exertion. The cause of fatigue is complex, influenced by events occurring in both the periphery and the central nervous system. Because fatigue may result from a number of causes, it should be treated comprehensively. The treatment is largely symptomatic and rehabilitative.

• Korean Journal of Logic
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• v.14 no.2
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• pp.77-104
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• 2011

Professor Hasuk Song argues that every argumentum ad ignorantiam, i.e. the argument from ignorance is not fallacious, and social contexts play a crucial role to judge whether the argument is fallacious or not. I generally agree with him, but I think we cannot have help from his position without knowing what those contexts are. In this paper, I argue that the concept of burden of proof is the crucial one to judge whether ad ignorantiam is plausible or not, and then present four criterions who have the burden of proof. There is a burden of proof on one who argues first, who insists the doubtful ones, who has powers, and who thinks that a situation is not dangerous.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.263-270
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• 2010

This is a research on development of water purification equipment called artificial floating island (=AFI) for the stagnant water area which can secure exuberant landscape and water-friendility. The equipment devised in this study is designed to make up the weakness of conventional AFIs and improves the removal efficiency of pollutants using the mixture of media and plants. The air compressor positioned at the inlet releases air with inflow continuously, the water pump at the outlet sprays as a form of fountain with causing a disturbance on stable water column, then, both of them contribute improvement of water quality over a large area. We applied Bio-stone as a media in this system and performed an experiment of pre-efficiency test, and we concluded that the higher pollutants concentration of inflow, the higher removal efficiency we obtained. At the result of lab-scale experiment, in the case of high-concentration inflow, in the removal efficiency of SS is 62.2%, BOD is 50.2%, COD is 55.1%, T-N is 31.6%, T-P is 38.4%. In addition, to evaluate the field application, we set up the facilities in Sin-gal lake located in Yongin-Si Gyeonggi-Do, and researched on the removal efficiency of outflow relative to the inflow. As a result, SS is 53.5%, BOD is 32.8%, COD is 36.9%, T-N is 22.6%, T-N is 33.2%.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2001.11a
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• pp.115-122
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• 2001

본 개발대상 장치인 풍력을 통한 하강류 형성장치는 심층에 산소를 공급하여 패류가 증식하게 하므로 정화를 할 수 있도록 하는 장치이다. 본 연구의 결과, 풍력 저수지 수질개선장치를 통해 모든 호소의 수질등급을 상향시킬 수 있을 것이다. 특히, 새만금, 시화호 등 문제 있는 호소까지 인간에 유익한 수질로 개선 함으로써 국가적인 이익은 물론 전세계의 수원을 정화하여 인류의 수자원 문제를 해결할 수가 있을 것이다. 동력에 의한 방법은 언제든지 적용할 수 있지만, 풍력에 의한 장치로 에너지 비용과 설치비용을 절감하는 것이 본 개발대상 장치를 통해 얻을 수 있는 효과이다. 현재 국내의 저수지는 약 12,000개소에 달한다 이 저수지들에 오염도에 따라 5대～200대 정도를 설치할 경우(소양이나 새만금 등), 장치의 대당 가격이 1,000 만원～1,500 만원이므로 국내 수요로 약 2조 4천억원의 내수시장이 형성될 수 있을 것이다.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.04a
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• pp.163-170
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• 1998

The influence of the dam-reservoir interaction on the seismic response of dams is studied. The impounded water is assumed to be inviscid and compressible ideal fluid. Material damping is introduce to simulate the energy loss of wave propagation in the water. The irregular region of the impounded water adjacent to the dam is modeled by boundary element method. The regular region extending to infinity is modeled by the transmitting boundary. The dam body is assumed to behave elastically and modeled by finite element method. The coupled equation of motion is obtained by substructure method.

• Korean Journal of Ecology and Environment
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• v.36 no.2 s.103
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• pp.124-138
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• 2003

This paper aimed to analyze the relationship between alga3 bloom patterns and hydrological, limnological data which were collected from major reservoirs in Korea for 8 years (1990${\sim}$1997). Water temperature of river-type reservoirs showed wider seasonal fluctuations than that of lake-type. pH of lake-type reservoirs was low in winter season but high in summer season. In contrast, river-type reservoirs showed high pH in spring and autumn seasons as well, and very low in summer season. COD of lake-type reservoirs and Paldang reservoir was lower (2${\sim}$3 mg/L) than that of Geumgang and Nagdonggang reservoirs (6${\sim}$9 mg/L). Dissolved oxygen (DO) of river-type reservoirs was higher than that of lake-type reservoirs. Seasonal fluctuation pattern of DO saturation in river-type reservoirs was high (80 ${\sim}$100%) and remained relatively constant whereas lake-type reservoirs showed the highest level (93%) in late spring or early summer, which gradually decreased entering winter season(46${\sim}$06%). And monthly variation of DO saturation showed inverse proportion to water volume in lake-type reservoirs. Nutrients concentration in river-type lake is higher than lake-type. Seasonal fluctuation of nutrients (T-N, T-P) in lake-type reservoirs was relatively small than that of river-type reservoirs. Annual mean N/P mass ratio of lake-type reservoirs was higher than that of river-type. Transparency tended to related with the suspended solid concentration in river-type reservoirs. Algal bloom of lake-type and river-type reservoirs occurred at any time except rainfall and winter periods. And it dominated in summer and early autumn, respectively. Algal bloom of river-type reservoirs was higher than that of lake-type. Relationship between rainfall and chlorophyll- a in lake-type reservoirs was relatively high, however river-type reservoirs showed insignificant.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.322-324
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• 2019

하천과 호소수에서 상당 부분의 수자원을 얻는 국내 상황을 고려할 때 하천 수질사고는 심각한 상황을 초래할 수 있다. 이 논문에서는 이동할 수 있는 수질 측정 장치와 측정한 수질 정보를 웹 페이지를 통해 사용자에게 제공하는 시스템을 제안한다. 수질 측정 장치는 모형 배 형태이다. 관리자는 블루투스 통신으로 수질 측정 장치를 조종할 수 있다. 측정한 수질 정보를 와이파이 모듈을 통해 외부 서버의 데이터베이스에 저장한다. 사용자는 웹 페이지를 통해 실시간으로 측정되는 수질 정보를 확인할 수 있다. 구현 결과, 가벼운 무게와 조종 가능한 특성으로 이동성의 개선과 웹페이지를 통한 실시간 시각화를 확인하였다.

• Journal of Korea Water Resources Association
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• v.34 no.3
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• pp.265-273
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• 2001

In this study, a hydrocyclone operated by centrifugal force was examined as a part of dredge system of lake sediments. It does not help dehydration of the sediments, but also enables the classification of fine particles in the stable and sanitary treatment. Several experiments were performed focusing on the separation efficiency under the condition of room temperature with virtual sediment samples and simulated particles. As a result of the experiment, it was found that the apex size of the cyclone greatly affected the cut diameter(d$_{50}$), and high density particles were separated more effectively.y.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.165-165
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• 2022

담수호는 하구에 방조제를 축조하여 인위적으로 조성된 저수지로, 배수갑문을 통해 적정수위를 유지하면서 이수 목적의 수자원으로 재활용할 경우 경제적이며 효율적인 수자원이 될 수 있다. 한편, 담수호는 유역의 최하류에 위치하므로 담수호의 통합적 수자원 관리를 위해서는 상류 유역 특성과 유입 오염물질 및 수체 특성에 대한 종합적인 이해를 바탕으로 수문, 수질, 염도 등 다양한수자원 요소를 고려하여 적절한 관리방안을 수립할 필요가 있다. 따라서 본 연구에서는 유역모형 및 호소모형을 연계하여 담수호의 내외 수위차를 고려한 배수갑문 운영 시나리오에 따른 호내 수문 및 수질 측면에서의 영향을 정량적으로 분석하였다. 충청남도 서산시에 위치한 간월호를 대상으로 HSPF (Hydrological Simulation Program-FORTRAN) 모형을 적용하여 상류유역의 장기유출량 및 수질 모의를 수행하여 호내 유입량 자료로 활용하였다. 호소 내 수리-수질 모의를 위해 3차원 수리해석 모형인 EFDC (Environmental Fluid Dynamics Code)와 호소수질모의 모형인 WASP (Water Quality Analysis Simulation Program)을 연계하여 배수갑문 운영에 따른 호내 수문 및 수질 변화를 모의하였다. 본 연구의 결과는 향후 수문 및 수질 영향을 고려한 담수호의 최적 수자원 관리방안 수립하는데 기초자료로 활용될 수 있을 것으로 기대된다.

• Korean Journal of Ichthyology
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• v.6 no.1
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• pp.28-38
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• 1994

The ichthyofauna was investigated in Tongbok Lake and its tributaries from October, 1992 to January, 1993. Twenty-nine species representing 23 genera and 10 families were collected. Twenty-eight species in 22 genera and 9 families were from the stream area, while sixtween species in 14 genera and 7 families were from the lake area. Among these 14 species were classified as endemic species in Korea. Dominent species in the stream area were Zacco temmincki(28.04%) and Z. platypus (16.76%), whereas the lake area was overwhelmingly dominated by Hypomesus olidus(55.22%) and Z. platypus(44.31%). In the stream area. species diversity indices, evenness indices and dominant indices were 1.056, 0.730 and 0.270, respectively. In the area, the indices for species diversity, evenness and dominance were 0.314, 0.261 and 0.739, and those of body weights were 0.361, 0.300 and 0.700, respectively.