• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.2
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• pp.198-203
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• 2020

In this paper, we propose an artificial water level prediction system for small river flood prediction. River level prediction can be a measure to reduce flood damage. However, it is difficult to build a flood model in river because of the inherent nature of the river or rainfall that affects river flooding. In general, the downstream water level is affected by the water level at adjacent upstream. Therefore, in this study, we constructed an artificial intelligence model using Recurrent Neural Network(LSTM) that predicts the water level of downstream with the water level of two upstream points. The proposed artificial intelligence system designed a water level meter and built a server using Nodejs. The proposed neural network hardware system can predict the water level every 6 hours in the real river.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.1
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• pp.83-90
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• 2020

A commercial flow measurement radar sensor estimates a quantity of flowed water using surface flow rate. In this way, the amount of water flowing per unit time cannot be measured accurately because of using an estimation result and it can't response environmental changes. For more accurate flow measurements we need width of waterway, water level and distance that water moved per unit time. Commonly two sensors are used to measure water level and flow rate. In this paper, we propose a method to simultaneously measure the water level and surface flow velocity using a single FMCW radar sensor and design the transmission waveform. In order to verify the waveform design, received signal is modelled based on transmission waveform. In addition, we consider phenomenons and problems that may occur in signal processing.

• Proceedings of the Korea Contents Association Conference
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• 2014.06a
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• pp.83-84
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• 2014

For hydrologic applications, lake levels is very important. As a first step in developing a remote-sensing based approach, lake stage estimation using remote sensing was proposed with the SRTM data from February 2000, which was providing a one-time snapshot. After several steps using contouring, masking, and CED, it was found that iterative contour fitting to a lake outline provided the outstanding result with the operator's decision. If the lake size is large enough, a constant meter of the difference removal due to bias found by Bhang et al. (2007) might be useful for more accurate estimations for the methods. A lake-level snapshot using SRTM data could provide estimates within 0.5 m level of accuracy for large lakes (> $10km^2$) with contouring. Also, even if the processing algorithm is complex, the accuracy was reliable. Overall, we confirmed that this study would provide useful information to ameliorate the quality of the SAR-derived DEMs specifically for water areas and if more expanded, SAR images can fruit result in water monitoring.

• Journal of Environmental Impact Assessment
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• v.13 no.6
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• pp.285-294
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• 2004

The purpose of this study is to understand the quantitative change of water resources using RMS(Remote Monitoring System) which takes real time data with high reliability. Also, the characteristic of stormwater runoff was understood by the application of the above system for three streams (Jiam, Yulmun, and Gongji stream) in Chuncheon City. The detailed results of these studies are as follows; RMS(Remote Monitoring System) was constructed by the combination of the automatic water-level meter, which measures water-level of streams at all times, and the wireless communication system sending real-time data from the meter. This system is used to evaluate the stormwater runoff in watersheds and the quantitative changes of streams. It is possible to overcome the limit of field investigations needed, which takes a lot of manpower and time, and it is very efficient to provide the reliable flowrate data. Also, it can be applied to the disaster prevention system for flood because the change of flowrate in stream is monitored at real-time. For 3 streams with different watershed characteristics, correlation equations induced from the relation analysis results. In terms of the relation between water-level and flowrate, flowrate was increased rapidly as the water-level rises in case of small watershed and steep slope. The application results of the proposed system for 3 streams (Jiam, Yulmun, Gongji) in Chuncheon city are as follows; The remote monitoring system was very useful for acquisition of the flow rate in stream that are basic data to understand pollutants runoff in watershed. In case of no-rainy day, the runoff ratio for pollutant loading rate was the highest level in Yulmun stream(BOD:2.3%, TN:20.2%, TP:1.2%). So, it shows the management of pollution source is needed such as rehabilitation of sewer line. Runoff ratio of total phosphorus by rainfall in Gongji watershed was increased about 19 times than no-rainy day, which is estimated as the influence of sewer overflow.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.11 no.4
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• pp.133-144
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• 2006

It is investigated using ADCIRC model to find an optimal gate operation in order to maintain target water level of the inner Saemangeum Reservoir. Various developing procedures and river inflows conditions are considered in modeling. For the gate operations, consecutive openings to inflow and outflow, such as once a day, twice a day and once per two days are considered. However water level increases gradually due to river inflows regardless of gate operations. In order to maintain target level 0.0 m, it is recommended to shut down of gate in order to prevent inflows of outer sea water at least once per 6 days for normal riverine inflows and once per 3 days for flood inflows during consecutive operations. Then it is balanced within maximum of ${\pm}0.4m$ of deviations from target level of 0.0 meter.

• The Journal of Engineering Geology
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• v.20 no.2
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• pp.169-181
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• 2010

This study aimed at simulating several responses to stresses caused by the ground water level variations around the K-1 oil stockpile. For this simulation, we considered the characteristic hydrogeological condition including the special occurrence of long and thick acidic dyke, which is regarded as the main geological structure dominating the ground water flow system at this study area. We activated twenty-four imaginary wells which are located in northern and southern area around central K-1 site. Each neighboring distance is altogether 300 m and whole distance between K-1 site and remote wells is 1,200 m. Through the modeling, we operated the long-term and continuous pumping tests and finally categorized five zones based on maximum pumping rates for the imaginary wells; zone I within 300 meter distance from K-1 site with a pumping rate of 50 $m^3/day$; zone II between 300 to 600 meter distance from K-1 site with a pumping rate of 75 $m^3/day$; zone III between 600 to 900 meter distance from K-1 site with 150 $m^3/day$; zone IV between 900 to 1,200 meter distance from K-1 site with 300 $m^3/day$; and zone V of acidic dyke area. At zone V, especially because of their possibility of high transmissivity for groundwater flow, it is necessary to control and restrict groundwater discharge.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1666-1668
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• 2004

By wireless transmission data, there is high possibility to get distortion and lose by noise and barrier on wireless. If the data check damaged and lost at receiver, can't make it clear and can't judge whether this data is right or not. Therefore, by wireless transmission data need the data error check algorithm in order to decrease the data's distortion and lose and to monitoring the transmission data as real time. This study consists of RF station for wireless transmission, Water Level Meter station for water level measurement and Error check algorithm for error check of transmission data. This study is also that investigation and search for error check algorithm in order to wireless digital data transmission in condition of the least data's damage and lose. Designed transmitter and receiver with one - chip micro process to protect to swell the volume of circuit. Had designed RF transmitter - receiver station simply by means of ATMEL one - chip micro process in the systems. Used 10mW of the best RF power and 448MHz-449MHz on frequency band which can get permission to use by Frequency Law made by Korean government

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.567.2-567
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• 2001

The purpose of this study was to evaluate the shape, the composition of Calcium Hydroxide Points (CH Point) and to determine the pH level in water. The shape of CH Point was measured by using a profile projector. The composition of the CH Point was analyzed by the X-ray diffraction and the EPMA. ＃60 CH Point was stored in 10ml of demineralized water that was replaced every day or not replaced for 7 days period. The pH levels of the water were measured by using an ion electrode with an ion meter every day.(omitted)

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.315-315
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• 2017

In Japan, more than 80 % of soybean growing area is converted fields and excess water is one of the major problems in soybean production. For example, recent study (Yoshifuji et al., 2016) suggested that in the fields of shallow groundwater level (GWL) (< 1m depth), rising GWL even in a short period (e.g. 1 day) causes inhibition of soybean growth. Thus it becomes more and more important to predict GWL and soil moisture in detail. In addition to conventional surface drainage and underdrain, FOEAS (Farm Oriented Enhancing Aquatic System), which is expected to control GWL in fields adequately, has been developed recently. In this study we attempted to predict GWL and soil moisture condition at the converted field with FOEAS in Biwa lake reclamation area, Shiga prefecture, near the center of the main island of Japan. Two dimensional HYDRUS model (Simuinek et al., 1999) based on common Richards' equation, was used for the calculation of soil water movement. The calculation domain was considered to be 10 and 5 meter in horizontal and vertical direction, respectively, with two layers, i.e. 20cm-thick of plowed layer and underlying subsoil layer. The center of main underdrain (10 cm in diameter) was assumed to be 5 meter from the both ends of the domain and 10-60cm depth from the surface in accordance with the field experiment. The hydraulic parameters of the soil was estimated with the digital soil map in "Soil information web viewer" and Agricultural soil-profile physical properties database, Japan (SolphyJ) (Kato and Nishimura, 2016). Hourly rainfall depth and daily potential evapo-transpiration rate data were given as the upper boundary condition (B.C.). For the bottom B.C., constant upward flux, which meant the inflow flux to the field from outside, was given. Seepage face condition was employed for the surrounding of the underdrain. Initial condition was employed as GWL=60cm. Then we compared the simulated and observed results of volumetric water content at depth of 15cm and GWL. While the model described the variation of GWL well, it tended to overestimate the soil moisture through the growing period. Judging from the field condition, and observed data of soil moisture and GWL, consideration of soil structure (e.g. cracks and clods) in determination of soil hydraulic parameters at the plowed layer may improve the simulation results of soil moisture.

• Journal of Korea Water Resources Association
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• v.41 no.5
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• pp.483-489
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• 2008

Recently, we have a growing interest in the washland construction for the function of flood defense in flood season and also as an ecosystem in non flood season. Therefore this study performed the hydraulic and hydrologic analysis for washland construction plan as sustainable flood defense alternative in flood season and wetland application possibility. The study area is Topyoung-cheon basin in Changnyeong-gun, Gyeongnam. A Topyoung-cheon basin includes a Woopo wetland which is the largest nature wetland in Korea and a Topyoung-cheon is ond of the tributaries of Nakdong river. We assume that the artificial washland is constructed in upperstream and downstream of Woopo wetland, and In flood season, the hydraulic analysis for the investigation of the effectiveness of flood level mitigation is performed by HEC-RAS model. Simulation of model is performed from 7 scenarioes of washland construction. As the result in flood season, the flood level is reduced by maximum 0.56 meter as we construct the washlands by 7 scenarios. Also, we performed hydrologic analysis for the investigation of water balance in washland in non flood season using SWAT model. From the result of water balance analysis, we found that the minimum water level of washland was maintained in about 1.3 meter for one year.