In this study, we performed algorithms to predict algae of Chlorophyll-a (Chl-a). Water quality and quantity data of the middle Nakdong River area were used. At first, the correlation analysis between Chl-a and water quality and quantity data was studied. We extracted ten factors of high importance for water quality and quantity data about the two weirs. Algorithms predicted how ten factors affected Chl-a occurrence. We performed algorithms about decision tree, random forest, elastic net, gradient boosting with Python. The root mean square error (RMSE) value was used to evaluate excellent algorithms. The gradient boosting showed 10.55 of RMSE value for the Gangjeonggoryeong (GG) site and 11.43 of RMSE value for the Dalsung (DS) site. The gradient boosting algorithm showed excellent results for GG and DS sites. Prediction value for the four algorithms was also evaluated through the Receiver operating characteristic (ROC) curve and Area under curve (AUC). As a result of the evaluation, the AUC value was 0.877 at GG site and the AUC value was 0.951 at DS site. So the algorithm‘s ability to interpret seemed to be excellent.

Recently, advanced metering infrastructure (AMI) has been recognized as a core technology of smart water grid, and the relevant market is growing constantly. In this study, we developed all-in-one smart water meter of the AMI system, which was installed on the test-bed to verify both effectiveness and field applicability in office building water usage. Developed 15 mm-diameter smart water meter is a magneto-resistive digital meter, and measures flow rate and water quality parameters (temperature, conductivity) simultaneously. As a result of the water usage analysis by installing six smart water meters on various purposes in office building water usage, the water usage in shower room showed the highest values as the 1,870 L/day and 26.6 liter per capita day (LPCD). But, the water usage in laboratory was irregular, depending on the many variables. From the analysis of the water usage based on day of the week, the water usage on Monday showed the highest value, and tended to decrease toward the weekend. According to the PCA results and multivariate statistical approaches, the shower room (Group 3) and 2 floor man’s restroom sink (Group 1-3) have been classified as a separate group, and the others did not show a significant difference in both water use and water quality aspects. From the analysis of water usage measured in this study, the leak or water quality accident did not occur. Consequently, all-in-one smart water meter developed in this study can measure flow rate and water quality parameters (temperature, conductivity) simultaneously with effective field applicability in office building water usage.

A comprehensive water budget analysis considering the water consumed for landfill gas formation was performed for Sudokwon Landfill Site 2 (LS2) from October 2000 through December 2016. The weighted average mole ratios of carbon (C), hydrogen (H), and oxygen (O) of the total disposed waste were 30.4%, 48.8%, and 20.8% respectively. The total emitted H and O as CO2 and CH4 from landfill gas was 2,812×103 Mg, of which 28.6% (803×103 Mg) was supplied from water. The total emitted water quantity consisted of landfill gas at 8.4%, leachate at 90.2%, and vapor in landfill gas at 1.4%. The total supplied water quantity to LS2 was 22.0×106 Mg, and the quantity supplied from water included in disposed waste was 62.9%. Considering the supplied and emitted water quantity, the retained quantity in LS2 was estimated to be 12×106 Mg, and the emitted and retained quantities were 43.3% and 56.7%, respectively. Considering the retained quantity, the water content in LS2 was estimated to be 26.0%, far below the optimum level for landfill site stabilization.

This study was conducted examine the workability of LEFC in relation to unit quantity of water and fiber addition. The LEFC should secure low weight and good flow by mixing light weight aggregate because the fresh concrete should cured so that gaps do not form between the acrlyic wedges and the concrete with the fresh. The slump tests revealed that fresh concrete with 180 units of water and 0.1% fiber content and fresh concrete with 190 units of water and 0.1%, 0.2% fiber content respectively had excellent workability.

This study was conducted examine the workability of LEFC in relation to unit quantity of water and fiber addition. The LEFC should secure low weight and good flow by mixing light weight aggregate because the fresh concrete should cured so that gaps do not form between the acrlyic wedges and the concrete with the fresh. The slump tests revealed that fresh concrete with 180 units of water and 0.1% fiber content and fresh concrete with 190 units of water and 0.1%, 0.2% fiber content respectively had excellent workability.

본 연구에서는 북한의 발전(發電) 수자원 가능량을 조사하기 위해 포장수력 이론을 적용하였다. 발전수자원 가능량이라 함은 발전을 할 수 있는 수자원의 양을 뜻하며, 유역의 수자원을 효율적으로 사용할 수 있는 지점에 댐을 건설하기 위해 조사한다. 포장수력은 전원개발의 대상이되는 수력자원의 크기를 의미하며 수력에너지의 부존특성 개발의 방식 등을 감안하여 이론포장수력, 기술적 포장수력, 경제적 포장수력 등 3가지 유형으로 구분되나 본 연구에서는 북한의 자료의 한계로 인해 이론포장수력조사 방법에 대해서만 산정하였다. 이론포장수력이란 높은 곳에서 강하한 강수가 유역을 따라 해면까지 유하하는 데서 얻을 수 있다고 보는 유수의 잠재적 에너지로서 총 낙차와 강수량의 상승적 비례관계에 따라 산정한다. 북한의 압록강, 두만강 등 총 7개의 유역에 대해서 북한의 이론포장수력을 산정하였다. 이를 위해 북한의 27개의 강우관측소 자료를 이용해 유역별 강수량을 산정하였고 북한의 고도별 면적 강수량을 산정하기 위해 MODIS에서 제공하고 있는 Aster Gdem에서 북한 지역의 DEM을 추출하여 본 연구에 이용하였다. 이론포장수력 산정 결과 압록강유역이 7562.2×10³KW으로 가장 높았으며, 상대적으로 높은 표고에 위치한 압록강과 두만강에서 높게 산정되었다. 북한의 발전 수자원 가능량을 조사함으로써 유역의 수자원을 효율적으로 사용할 수 있는 지점을 파악할 수 있으며, 수자원의 장래 개발 가능성을 파악하고 그 개발을 촉진시키는 데에 지침이 되는 기본 자료로서 활용이 가능할 것으로 예상 된다.

본 연구는 최근 하천유지유량에서 중요한 위상을 차지하고 있는 하천생태계에서 어류 서식처를 보전하고 복원하는데 필요한 적정 유량을 산정하는 것이 주된 목적이다. 어류 서식처를 적절히 유지할 수 있는 연과 월갈수량을 산정한다. 이 갈수량을 이용하여 점변 흐름에서 어류 서식처 제공에 필요한 수심과 유속을 모의하고, 또한 수온과 용존산소를 예측한다. 예측된 각 갈수량별 서식 조건과 각 성장단계별 어류 서식처 요구 조건을 도식적으로 비교하다. 이 과정을 남한강의