• Journal of Korea Water Resources Association
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• v.47 no.4
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• pp.307-319
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• 2014

Because of the rapid rising of water related disasters due to the global warming, the extreme design criteria of levee construction for severe flood has been applied in several developed countries such as USA and Netheland. In Korea, the national river restoration projects were carried out on 4 major rivers in recent several years. The projects consisted of riverbed dredge and levee reinforcement, and new construction have caused wide change of river environment. However, concrete countermeasures for levee safety and river management have not been suggested until now. Therefore, this study assesses the levee safety of Yulji levee located in Hoechon, Nakdong Basin, where the Levee Seepage Monitoring System installed. The stability of levee is assessed based on the simulation performed by SEEP/W(2D unsaturated seepage model) and the simulated results are compared with the observed data. The effects of the flood wave and levee shape on the levee safety are investigated through several simulations.

• Journal of Digital Convergence
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• v.16 no.4
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• pp.49-54
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• 2018

Russia has access to unique port locations and routes, one of them is North Sea route, which have been a major debate topic for last several decades. In order to handle any shipments along the route, an adequate and capable port system must be present. This study aims to identify development and competition patterns from 2007 to 2016 of Russian ports in the Arctic basin, concentration trends in particular. The objectives achieved through utilizing the Herfindahl-Hirschman Index (HHI), concentration ratio (CR), the Gini coefficient and Lorenz curve, and shift-share analysis. Results demonstrate concentration trend, positive overall growth and lack of real competition. Originality of this study lies in the fact that certain analysis had not been done in previous studies, but importance of it may be found in several papers. Findings of this paper may assist policy-makers, port authorities and other researchers in understanding and further study on the region.

• Journal of the Korean Geographical Society
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• v.48 no.1
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• pp.112-127
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• 2013

It is unsuitable for Korean coastal information to work specific tasks because the coastal information of the current provides simple information, and thus the coastal information is required to reprocess. Therefore, this paper intends to present the ontology model for managing the coastal information using Geo-Ontology and seek application of ontology. The contents of this paper follow as; First of all, I considered the base theories for ontology and related researches. Second, I built Geo-Ontology which defines taxonomy of geographical features and their relationships. Third, I designed and implemented the coastal information ontology about basin of coast, Masan, using Geo-Ontology. Fourth, I carried out semantic queries and reasoning, assessment of the coastal information ontology. This paper will be a base study for many projects which are currently being conducted to integrate spatial information for more effective administrative works and easier maintenance and management of data. Also, this paper is significant in the sense that it is the study preparing for linked data.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.373-377
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• 2004

Since, in 1970, diatoms and diatom indices was first used in measuring quality of streams and rivers at the Seine Water Agency in France, five other water agencies began to show interests since 1990. In 1994, associated with CEMAGREF (Centre National du Machinisme Agricole du Genie Rural et des Eaux et des Forets : environmental science and expertise for the sustainable management of land and water), the six French Water Agencies (Seine, Rhone-Mediterranee-Corse, Artois- Picardie, Loire-Bretagne, Rhin-Meuse and Adour-Garonne) developed a practical diatom index, which is liable to be used routinely in the territorial streams and rivers of whole France, and which is liable to promote and facilitate its use in monitoring water networks. In 1995, the first version of a biological diatom index (IBD) was generated by them. Since then, the software update for IBD calculation and the user's network have led to numerous practical applications in France. Furthermore, the Water Agencies have run applicable programs on the National Basin Network from 1996, and the initial data set of IBD was completed. Re- examination of the complete data set was done at the end of 1998, and the tests on different calculation options of the IBD led to a third version of this index in June,2000 (AFNOR NF T 90-354).

• Journal of Korean Society on Water Environment
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• v.30 no.3
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• pp.329-339
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• 2014

This study aims to estimate chlorophyll-a concentration in rivers using multi-spectral RapidEye imagery and Spectral Mixture Analysis (SMA) and assess the applicability of SMA for multi-temporal imagery analysis. Comparison between images (acquired on Oct. and Nov., 2013) predicted and ground reference chlorophyll-a concentration showed significant performance statistically with determination coefficients of 0.49 and 0.51, respectively. Two band (Red-RE) model for the October and November 2013 RapidEye images showed low performance with coefficient of determinations ($R^2$) of 0.26 and 0.16, respectively. Also Three band (Red-RE-NIR) model showed different performance with $R^2$ of 0.016 and 0.304, respectively. SMA derived Chlorophyll-a concentrations showed relatively higher accuracy than band ratio models based values. SMA was the most appropriate method to calculate Chlorophyll-a concentration using images which were acquired on period of low Chlorophyll-a concentrations. The results of SMA for multi-temporal imagery showed low performance because of the spatio-temporal variation of each end members. This approach provides the potential of providing a cost effective method of monitoring river water quality and management using multi-spectral imagery. In addition, the calculated Chlorophyll-a concentrations using multi-spectral RapidEye imagery can be applied to water quality modeling, enhancing the predicting accuracy.

• Journal of Ecology and Environment
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• v.38 no.2
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• pp.145-156
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• 2015

This study was based on water quality data of the Lake Doam watershed, monitored from 2010 to 2013 at eight different sites with multiple physiochemical parameters. The dataset was divided into two sub-datasets, namely, non-rainy and rainy. Principal component analysis (PCA) and factor analysis (FA) techniques were applied to evaluate seasonal correlations of water quality parameters and extract the most significant parameters influencing stream water quality. The first five principal components identified by PCA techniques explained greater than 80% of the total variance for both datasets. PCA and FA results indicated that total nitrogen, nitrate nitrogen, total phosphorus, and dissolved inorganic phosphorus were the most significant parameters under the non-rainy condition. This indicates that organic and inorganic pollutants loads in the streams can be related to discharges from point sources (domestic discharges) and non-point sources (agriculture, forest) of pollution. During the rainy period, turbidity, suspended solids, nitrate nitrogen, and dissolved inorganic phosphorus were identified as the most significant parameters. Physical parameters, suspended solids, and turbidity, are related to soil erosion and runoff from the basin. Organic and inorganic pollutants during the rainy period can be linked to decayed matters, manure, and inorganic fertilizers used in farming. Thus, the results of this study suggest that principal component analysis techniques are useful for analysis and interpretation of data and identification of pollution factors, which are valuable for understanding seasonal variations in water quality for effective management.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.2
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• pp.219-229
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• 2016

This study presents the analysis of flood and bed deformation caused by reservoir failure. The CCHE1D is used to simulate 1D non-uniform, non-equilibrium sediment transport and bed deformation. The CCHE1D deals with the adaptation length for non-equilibrium sediment, classified sediment particle for non-uniform sediment and mixing layer for the exchange with the sediment moving with the flow. The model is applied to Ha!Ha! river basin where was experienced reservoir failure in 1996 to analyze non-uniform and non-equilibrium sediment transport. The calculations are compared with morphological bed changes of pre- and post-flood. In addition, model sensitivity to main parameters involving adaptation length ($L_{s,b}$), non-equilibrium coefficient (${\alpha}_s$), mixing layer thickness (${\delta}_m$) and porosity (p') is analyzed. The results indicates that thalweg change is the most sensitive to non-equilibrium coefficient (${\alpha}_s$) among those parameters in the study area.

• Journal of Korean Society for Atmospheric Environment
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• v.22 no.4
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• pp.468-476
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• 2006

Hazardous air pollutants (HAPs) have high toxicity and bioaccurnulation potentials into human body even inbsmall amount (levels of ng/$m^3$). As the levels of HAPs might be controversial, it has been become essential to establish the analysis method for correct results. In this study, various analysis methods of VOCs and Aldehydes were compared in order to select the proper methods in our condition. Sampling and analysis method of VOCs were followed to EPA TO-14a and TO-17. VOCs were collected in absorption tube and separated by thermal desorption unit then analyzed by GC/MSD. Aldehydes were sampled in DNPH-cartridge and extracted into solution then analyzed by HPLC as the same condition of EPA TO-13a. This study also shows the results of QA/QC system of selected methods. Some experiments could be improving the data assurance blank test, calibration check, repetition precision check, the determination of detection limit and reproducibility of the retention time. Precisions of VOCs and aldehydes were ranged in 2$\sim$9% and 1$\sim$4% RSD, respectively. Recovery rate of VOCs showed variable ranges from 60 to 133.5%. MDL of VOCs and aldehydes were 0.044$\sim$0.284 ppb and 0.14$\sim$1.02 ng, respectively.

• Journal of Environmental Impact Assessment
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• v.21 no.4
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• pp.543-552
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• 2012

Namgang mid-watershed is located in downstream of Nakdong river basin. There are many pollution sources arround this area and it's control is important to manage a water quality of Nakdong river. A target year of Namgang mid-watershed water environment management plan is 2013. To predict a water quality at downstream of Namgang, we have investigated and forecasted the pollutant source and it's loading. There are some plan to construction the sewage treatment plants to improve the water quality of Nam river. Those are considered on predicting water quality. As results, it is shown that the population is 343,326 and sewerage supply rate is 79.2% and the livestock is 1,662,000 in Namgang mid-watershed. It is estimated that the population is 333,980, the sewerage supply rate is 86.9% in 2013. The milk cow and cattle were estimated upward and the pigs were downward by 2013. The generated loading of BOD and TP is 75,957 kg/day and 4,311 kg/day, discharged loading is 18,481 kg/day and 988 kg/day respectively in 2006. It were predicted upward the discharged loading of BOD and TP by 4.08% and 6.3% respectively. The results of water quality prediction of Namgang4 site were 2.5 mg/L of BOD and 0.120 mg/L of TP in 2013. It is over the target water quality at that site in 2015 about 25.0% and 9.1% respectively. Consequently, there need another counterplan to reduce the pollutants in that mid-watershed.

• Journal of Soil and Groundwater Environment
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• v.7 no.4
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• pp.40-47
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• 2002

The practices of the construction and management of the petroleum and hazardous chemical compound storage facilities in Korea were investigated extensively, and the problems were identified. The advanced technologies in the U.S.A were comparatively studied. Considering the effectiveness of leak prevention and applicability, the following measures were suggested. To prevent corrosion of a tank, a clad tank, an interior lining tank, or a double-wall tank were thought to be the most cost effective. For piping. use of non-metalic materials was suggested. A catchment basin seemed to be effective for preventing spills. For monitoring of leaks, constructions of more than one of detection systems, such as an automatic leak detection device. a vapor detection system, a groundwater monitoring system, or a double-wall monitoring system, were recommended.