• 경영과학
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• 제30권1호
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• pp.91-102
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• 2013

This study has an aim to analyze the effects of ADS on conjunctivitis patients among the residents of Seoul, Korea, between 2005 and 2008. For this purpose, the number of medical services provided to conjunctivitis patients on the days of windblown dust storms and the days without any windblown dust storms were analyzed by conducting paired t-test. The interactive effects of the ADS density and the accuracy of ADS forecast on the fluctuation of conjunctivitis cases were also investigated. The results showed that, even with an accurate forecast issued 24 hours prior to the event, the average number of medical services provided for conjunctivitis was higher on the index days than the comparison days. On the other hand, in cases of failure to provide an accurate forecast 24 hours prior to the ADS event, the number of conjunctivitis attacks reported was statistically significantly higher on the index days for 3~5 days after the occurrence of a dust storm in relation to the comparison days. We also found that the rate of increase in asthma treatments on the index days with low level of $PM_{10}$ concentration rather than high $PM_{10}$ level was more significant for all lag days. This study provides evidence that ADS events are significantly associated with conjunctivitis symptoms and the failure to forecast ADS events with low $PM_{10}$ level might aggravate conjunctivitis disease.

• 대한원격탐사학회지
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• 제23권1호
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• pp.15-20
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• 2007

This study is to apply QuickBird satellite image for the simulation of storm runoff in a small rural watershed. For a $1.05km^2$ watershed located in Goesan-Gun of Chungbuk Province, the land use from the QuickBird image was produced by on-screening digitising after ortho-rectifying using 2 m DEM. For 3 cases of land use, soil and elevation scale (1:5,000, 1:25,000 and 1:50,000), SCS-CN and the watershed physical parameters were prepared for the storm runoff model, HEC-HMS (Hydrologic Modelling System). The model was evaluated for each case and compared the simulated results with couple of selected storm events.

• 상하수도학회지
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• 제23권3호
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• pp.271-276
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• 2009

Under current design standard, sewers are designed to drain stormwater generated up to 10 year return period of storms. This implies sewer flooding could occur from rainfall exceeding a 10 year return period. 5, 10, 20 and 30 year return period of storm intensities were calculated for 22 locations (cities) of meterological stations over the nation and compared to the recorded rainfall intensities for the last 30 years. The comparison resulted in the numbers of year maximum rainfall intensities exceeded each return period. Using the questionnaire survey for "the incidences of flooding since 1980" of the previous paper (Survey on sewerage operation/management planning for flooding (I)), the actual rainfall records on the date of flooding events were analyzed to demonstrate the number of flooding events caused by the exceedance of sewer capacity. For the last 30 years, more than 6 years of year maximum rainfall intensity (20%) were larger than the 10 year return period of storm in 4 cities of the 22 used for the first analysis. The number of rainfall records that exceeded the 10 year return period was 50 of the 260 actual flooding events investigated from the survey.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.602-605
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• 2006

This study is to apply QuickBird satellite image for the simulation of storm runoff in a small rural watershed. For a 1.05 $km^2$ watershed located in Goesan-Gun of Chungbuk Province, the land use from the QuickBird image was produced by on-screening digitising after ortho-rectifying using 2 m DEM. For 3 cases of land use, soil and elevation scale (1:5,000, 1:25,000 and 1:50,000), SCS (Soil Conservation Service)-CN (Curve Number) and the watershed physical parameters were prepared for the storm runoff model, HEC-HMS (Hydrological Modelling System). The model was evaluated for each case and compared the simulated results with couple of selected storm events.

• Journal of Astronomy and Space Sciences
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• 제25권2호
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• pp.113-128
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• 2008

Solar wind dynamic pressure enhancements are known to cause various types of disturbances to the magnetosphere. In particular, dynamic pressure enhancements may affect the evolution of magnetic storms when they occur during storm times. In this paper, we have investigated the statistical significance and features of dynamic pressure enhancements during magnetic storm times. For the investigation, we have used a total of 91 geomagnetic storms for 2001-2003, for which the Dst minimum $(Dst_{min})$ is below -50 nT. Also, we have imposed a set of selection criteria for a pressure enhancement to be considered an event: The main selection criterion is that the pressure increases by ${\geq}50%\;or\;{\geq}3nPa$ within 30 min and remains to be elevated for 10 min or longer. For our statistical analysis, we define the storm time to be the interval from the main Dst decrease, through $Dst_{min}$, to the point where the Dst index recovers by 50%. Our main results are summarized as follows. $(i){\sim}$ 81% of the studied storms indicate at least one event of pressure enhancements. When averaged over all the 91 storms, the occurrence rate is ${\sim}$ 4.5 pressure enhancement events per storm and ${\sim}$ 0.15 pressure enhancement events per hour. (ii) The occurrence rate of the pressure enhancements is about three times higher for CME-driven storm times than for CIR-driven storm times. (iii) Only 21.1% of the pressure enhancements show a clear association with an interplanetary shock. (iv) A large number of the pressure enhancement events are accompanied with a simultaneous change of IMF $B_y$ and/or $B_z$: For example, 73.5% of the pressure enhancement events are associated with an IMF change of either $|{\Delta}B_z|>2nT\;or\;|{\Delta}B_y|>2nT$. This last finding suggests that one should consider possible interplay effects between the simultaneous pressure and IMF changes in many situations.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.1093-1102
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• 2009

This study was focused on analyse Nonpoint source characteristics from Flat slope field and Steep slope field. We performed Storm-water monitering for obtain flow data and concentration data. Totally, eleven times Event was occurred. We calculated EMC(Event Mean Concentration) and Pollutants Loads using data we obtained. As a result, steep slope field has more discharge than flat field. SS value, one of the water quality contents, has largest variation and T-N has least variation. There is runoff differences even though events has same rainfall. We assume that not only amount of Rainfall, but also Rainfall Duration Times, Intensity, Number of Previous Non-precipitation days can affect to Run-off.

• 한국습지학회지
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• 제19권4호
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• pp.515-522
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• 2017

본 연구는 도시지역의 토지이용별 비점오염물질의 유출특성을 파악하고 적정 모니터링 횟수를 도출하고자 연구를 수행하였다. 연구 조사지점은 도시지역 중 주거지역(13지점), 상업지역(8지점), 교통지역(9지점), 공업지역(11지점)으로 선정하였으며 지점에 따라 2008년부터 2016년까지 모니터링이 수행되었으며 총 632회의 강우사상에 대한 모니터링 결과를 분석하였다. 분석결과, 상업지역의 경우 다른 토지이용에 비해 높은 유출률과 고농도의 오염물질이 유출되기에 다른 토지이용보다 비점오염원 관리시 우선적으로 관리가 필요한 것으로 나타났다. 또한 토지이용별 연간 모니터링 횟수를 산정한 결과, 공업지역의 경우 11~14회, 교통지역은 12~14회, 상업지역은 11~13회, 주거지역은 22~25회로 분석되었다. 다년간 축적된 모니터링 자료를 이용하더라도 일부 오염물질 항목에서 높은 오차가 나타남에 따라 여전히 높은 확률의 불확실성이 존재하며 지속적인 모니터링 수행으로 오차를 줄이기 위한 모니터링 노하우 정립 및 데이터 축적이 요구된다.

• 한국지형학회지
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• 제28권3호
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• pp.37-49
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• 2021

Analysis and prediction of storm surges are very important because the global warming has raised sea levels and increased the frequency of massive typhoons, accelerating damage of coastal flooding. However, the data for storm surge prediction is lacking due to the short history of observation in South Korea. The purpose of this study is to investigate the spatial and temporal characteristics of the previous surges and tsunamis based on the historical documents published during the Joseon Dynasty. In addition, we tried to evaluate the damage and spatial extent of such disasters, using the expressions about surge records including heights and number of administrative divisions. As a result, a total of 175 records of surges and tsunamis were compiled from 1392 to 1910: 145 events were extracted through the analysis of the ancient documents, and 30 events were from the previous research. Most of the strorm surges occurred along the west coast during summer season. More than half of the total surges were concentrated for 120 years from the mid 1600s to the mid 1700s, which was estimated to be highly relevant to the climate conditions in East Asia during the Little Ice Age. Hazardous areas by storm and tidal surges were also extracted, including Asan, Ganghwa, and Siheung during the Joseon Dyanisity period.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.141-141
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• 2021

This study proposed an equation for Rainfall Threshold for Flood Warning (RTFW) for urban areas based on computer simulations. First, a coupled 1D-2D dual-drainage model was developed for nine watersheds in Seoul, Korea. Next, the model simulation was repeated for a total of 540 combinations of the synthetic rainfall events and watershed imperviousness (9 watersheds × 4 NRCS Curve Number (CN) values × 15 rainfall events). Then, the results of the 101 simulations with the critical flooded depth (0.25m-0.35m) were used to develop the equation that relates the value of RTFW to the rainfall event temporal variability (represented as coefficient of variation) and the watershed Curve Number. The results suggest that 1) the rainfall with greater temporal variability causes critical floods with less amount of total rainfall; and that 2) the greater imperviousness requires less rainfall to have critical floods. For validation, the proposed equation was applied for the flood warning system with two storm events occurred in 2010 and 2011 over 239 watersheds in Seoul. The results of the application showed high performance of the warning system in issuing the flood warning, with the hit, false and missed alarm rates at 68%, 32% and 7.4% respectively for the 2010 event and 49%, 51% and 10.7% for the event in 2011.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.539-542
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• 2006

To investigate the streamflow impact of land cover changes by a typhoon, WMS HEC-1 storm runoff model was applied by using land cover information before and after the typhoon. The model was calibrated with three storm events of 1985 to 1988 based on 1985 land cover condition for a 192.7 $km^2$ watershed in northeast coast of South Korea. After the model was tested, it was run to estimate impacts of land cover change by the typhoon RUSA occurred in 2002 (31 August - 1 September) with 897.5 mm rainfall. The land covers before and after the typhoon were prepared using Landsat 7 ETM+ of September 11 of 2000 and Landsat 5 TM of September 29 of 2002 respectively. For the 6.9 $km^2$ damaged area (3.6 % of the watershed), the peak runoff and total runoff by the changed land cover condition increased 12.5 % and 12.7 % for 50 years rainfall frequency and 1.4 % and 1.8 % for 500 years rainfall frequency respectively based on AMC (Antecedent Moisture Condition)-I condition.