• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2003.10a
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• pp.55-72
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• 2003

Dam is a barrier constructed to divert, hold water and raise its level for purpose of water supply, irrigation, power generation, flood control, and recreational facilities, etc. Therefore, there are many inevitable environmental impacts on dam construction. We need some better tools to predict the impacts and mitigate measures before and after dam construction. For this purpose I discussed several feasible suggestions and provisions mainly related to environmental impact assessment.

• Ecology and Resilient Infrastructure
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• v.11 no.1
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• pp.24-24
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• 2024

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.4
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• pp.1433-1446
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• 2013

In this study, we proposed a methodology to develop Rating Curves for high water level using rainfall generation by the Monte Carlo Simulation (MCS) technique, optimized rainfall-runoff model, and flood routing model in an urban stream. The developed stage discharge Rating Curve based on observed data was contained flow measurement errors and uncertainties. The standard error ($S_e$) for observations was 0.056, and the random uncertainty ($2S_{mr}$) was analyzed by ${\pm}1.43%$ on average, and up to ${\pm}4.27%$. Moreover, it was found that the Rating Curve extensions by way of logarithmic and Stevens methods were overestimated to compare with the urban basin scale. Finally, we confirmed that the high water level extension by random generation of hydrological data using MCS can be reduced uncertainty of the high water level, and it will consider as a more reliable approach for high water level extension. In the near future, this results can be applied to real-time flood alert system for urban streams through construction of the high water level extension system using MCS procedures.

• Journal of Korea Water Resources Association
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• v.51 no.7
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• pp.555-564
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• 2018

The detention reservoir is a hydraulic structure that constructs a levee on the inland of river and sets up side weir in a section of the levee, and this facility stores a part of the flood volume in case of a flood event over a certain scale. In order to optimize the operation of detention reservoir, it is necessary to review the linkage with existing facilities in the river. In this study, the effect of water level reduction and the flow distribution was analyzed according to the location of the side weir in the detention reservoir considering the run-of-the-river gate. Two radial gates were installed in the experimental channel, and the water level in channel and the overflow of weir were measured by moving the location of the side weir upstream from the gate. As a results of experiment, it was confirmed that the water level reduction is more remarkable as the location of the side weir was closer to the gate, and the effect of flow distribution is not greatly changed. When two or more side weirs were operated, it is confirmed that the sufficient storage space was secured and the water level reduction effect with the location of the side weir is not large. In addition, the water level reduction rate according to the location of the side weir was estimated by empirical formula and it is provided as basic data that can be used in the planning of the detention reservoir.

• Journal of Korea Water Resources Association
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• v.51 no.12
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• pp.1207-1216
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• 2018

Discharge or water level predictions at tidally affected river reaches are currently still a great challenge in hydrological practices. This research aims to predict water level of the tide dominated site, Jamsu bridge in the Han River downstream. Physics-based hydrodynamic approaches are sometimes not applicable for water level prediction in such a tidal river due to uncertainty sources like rainfall forecasting data. In this study, TensorFlow deep learning framework was used to build a deep neural network based LSTM model and its applications. The LSTM model was trained based on 3 data sets having 10-min temporal resolution: Paldang dam release, Jamsu bridge water level, predicted tidal level for 6 years (2011~2016) and then predict the water level time series given the six lead times: 1, 3, 6, 9, 12, 24 hours. The optimal hyper-parameters of LSTM model were set up as follows: 6 hidden layers number, 0.01 learning rate, 3000 iterations. In addition, we changed the key parameter of LSTM model, sequence length, ranging from 1 to 6 hours to test its affect to prediction results. The LSTM model with the 1 hr sequence length led to the best performing prediction results for the all cases. In particular, it resulted in very accurate prediction: RMSE (0.065 cm) and NSE (0.99) for the 1 hr lead time prediction case. However, as the lead time became longer, the RMSE increased from 0.08 m (1 hr lead time) to 0.28 m (24 hrs lead time) and the NSE decreased from 0.99 (1 hr lead time) to 0.74 (24 hrs lead time), respectively.

• Nutritional Sciences
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• v.4 no.2
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• pp.104-111
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• 2001

The Purpose of this study was to investigate the dietary intake of nutrients and the use of vitamin and mineral supplements by Korean college students attending Web class and the socioeconomic, dietary and health-related factors involved. The subjects were 137 male and 115 female students amending a health and nutrition-related Web class at a cycler university. This cross-sectional survey was conducted by self-administered questionnaire and the data were analyzed by SAS and SPSS PC package programs. Nutrient intake data collected using three-day recall method were analyzed by the Computer Aided Nutritional Analysis Program. Average intake by male students of most nutrients except energy, vitamin B$_2$ and calcium and intake by female students of those except energy, vitamin $B_2$, calcium and iron was higher than Korean RDA. Nutrient intake of male students was significantly influenced by the mother s job, skipping meals, exercise, vitamin and mineral supplement use, flood supplement use and self-evaluated anemia. Skipping meals and flood supplement use significantly influenced the nutrient intake of female students. A total of 47.4% of male students and 53.9% of female students were vitamin and mineral supplement users. In female students, socioeconomic characteristics such as the father s education level and household income were significantly different between vitamin and mineral supplement users and non-users. In both male and female students, there were significant differences in cross analysis between vitamin and mineral supplement use and flood supplement use. As for the self-reported health status of male and female students, vitamin and mineral supplement users perceived their health status to be worse compared to non-users. Therefore, nutrition education via the Internet is necessary in order to encourage college students to practice optimal nutrition strategies, including maintaining well-balanced diets by choosing various floods wisely.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.11 no.1
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• pp.99-108
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• 1991

Rapid changes of urban hydrologic events need new management operation rule of detention reservoir which is essential outflow control system in urban area. Therefore, this study is to develop the outflow management method of Seoul city considering the Han river flood characteristics, to analyze the inundation of detention reservoir according to variation of design storm patterns, and to examine the safety of gate due to design flood water level. From this study, new operation rule is presented. The design storm patterns are determined by instantaneous intensity method and Huff's quartile method. And the inflow hydrograph of detention reservoir is obtained by applying ILLUDAS model and RRL method. The operation rule of existing drainage pump is designed to have linear relation between storage and pumping discharge. But in this study, it is effective for preventing inundation when the operation rule of drainage pump have Gaussian function which is combined the storage of detention reservoir with its inflow according to increasing or decreasing of inflow hydrograph.

• Spatial Information Research
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• v.19 no.4
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• pp.1-10
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• 2011

This research examined relationships between Scientifically Estimated Environmental Risks (SEERs) of floods, hurricanes and hazardous material releases, and household characteristics. This research showed that there were no statistically significant relationships between most of the demographic characteristics (age, household size, tenure at the present home) and SEERs of the two natural hazards (a flood and a hurricane). These results support Drabek's findings (1986) that people tend to underestimate or ignore natural hazards in selecting their residence regardless of age, household size, and house tenure. Educational attainment and yearly household income were positively correlated with hurricane risk, but not with flood risk. By contrast, SEER of hazardous materials was correlated with all demographic characteristics mentioned above. This result may show that those who are relatively poorer and have lower educational level tend to be limited to living in communities more vulnerable to human-made risk.

• Ecology and Resilient Infrastructure
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• v.4 no.1
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• pp.3-11
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• 2017

In this study, change in vegetation on bars was analyzed using the data on hydrology and river morphology with on-site photographic monitoring data for the sites of interest of the Naeseong Stream during the period from March 2013 to July 2016 when the impoundment of Yeongju Dam began. The effect of flow condition on burial and removal of vegetation covered on bar surfaces was elucidated by comparison of on-site photographic monitoring data with continuous water level plotted with on the cross-section profile. In 2014 burial happened due to late flood, while July flood caused burial and removal in 2016. On the contrary vegetation increased in 2015 due to low flow without flood. Results of this study showing natural changes in vegetation will be reference to changes which is expected to be caused by dam impoundment.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.5
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• pp.155-161
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• 2008

The flood damage shows different types in natural river watershed and in urban drainage watershed. In recent, increasing of the impervious area gives rise to short concentration time and high peak discharge comparing with natural watershed and it is a cause of urban flood damage. In this paper, we use a XP-SWMM model developed based on EPA-SWMM version for analyzing the inundation area, inundation depth and inundation area considering building effect. The two events(2005.06, 2005.07) has been used for the validation of model. HEC-RAS model has been applied for simulation of changing water level, and the results has been used for calculating area of the inundation. The observed inundation area(21.41 ha) in August, 1998 was in good agreement with the simulated value(23.45 ha) of XPSWMM model. An influence of inundation area considering building effects has been analized by the DTM of XP-SWMM model.