• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.447-450
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• 2010

Today a relatively small reservoirs and reclamation insufficient freshwater Agricultural Water Quality to collect and analyze information online, Analyzed in real-time information delivery and database hwahameurosseo agricultural water quality management of reservoirs and freshwater lakes can be systematically. In this paper, a remote user to automatically measure water and measured to provide information collected from each sensor and integrate information connected to your wireless network and Integrated control measures as well as real-time monitoring of the operational point of observation from a web site in real-time information about the water to retrieve the user's computer and the user consists of a mobile communication terminal.

• ALGAE
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• v.36 no.3
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• pp.195-206
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• 2021

Increasing inputs of dissolved organic matter (DOM) to northern lakes is resulting in 'lake browning.' Lake browning profoundly affects phytoplankton community composition by modifying two important environmental drivers-light and nutrients. The impact of increased DOM on native isolates of red and green-pigmented cyanobacteria identified as Pseudanabaena, which emerged from a Dolichospermum bloom (Dickson Lake, Algonquin Provincial Park, Ontario, Canada) in 2015, were examined under controlled laboratory conditions. The genomes were sequenced to identify phylogenetic relatedness and physiological similarities, and the physical and chemical effects of increased DOM on cellular performance and competitiveness were assessed. Our study findings were that the isolated red and green phenotypes are two distinct species belonging to the genus Pseudanabaena; that both isolates remained physiologically unaffected when grown independently under defined DOM regimes; and that neither red nor green phenotype achieved a competitive advantage when grown together under defined DOM regimes. While photosynthetic pigment diversity among phytoplankton offers niche-differentiation opportunities, the results of this study illustrate the coexistence of two distinct photosynthetic pigment phenotypes under increasing DOM conditions.

• Water for future
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• v.52 no.8
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• pp.56-66
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• 2019

Nepal is bestowed with abundant water. With more than 1500 mm average annual rainfall in the country, a vast quantity of underutilized groundwater in the Terai belt, and the water stored in snowcaps in the Himalayas, aquifers in the mountains and glacial lakes, Nepal is potentially in an advantageous position in terms of per capita availability. However, low emphasis in management aspect of water and high emphasis in infrastructural developments related to water resources management has resulted in conversion of water in Nepal from a resource to a burden. The global climate change, reduction in number of rainy days, increase in intensity of rainfall during wet monsoon season, encroachment of river banks for settlement, inadequate release of environmental flows from hydropower plants, and attempt to tame the mighty and high velocity rivers of Nepal have resulted in increasing number of water induced disasters (flood and landslide), rise in conflict between local residents and hydropower developers, higher number of devastating landslides, and in some extreme cases mass migration of residents resulting in climate refugees. There is a ray of hope; the awareness level of the people regarding sustainable use of water resources is increasing, the benefit sharing mechanism is gradually being implemented, the role of interdisciplinary and integrated water resources management is appreciated at a higher level and the level of preparedness against flood and landslides is at a higher degree compared to a couple of decades ago. With the use of renewable energy sources, the possibilities for sustainable and productive use of water are on the rise in Nepal.

• Geomechanics and Engineering
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• v.18 no.5
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• pp.493-502
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• 2019

Internal stability is an important safety issue for levees, embankments, and other earthen structures. Since a large part of the world's population lives near oceans, lakes and rivers, floods resulting from breaching of dams can lead to devastating disasters with tremendous loss of life and property, especially in densely populated areas. There are some main factors that affect the internal stability of dams, levees and other earthen structures, such as the erodibility of the soil, the water velocity inside the soil mass and the geometry of the earthen structure, etc. Thus, the mechanism of internal erosion and stability of soils is very complicated and it is vital to investigate the assessment methods of internal stability of soils in embankment dams and their foundations. This paper presents an improved support vector machine (SVM) model to predict the internal stability of soils. The grid search algorithm (GSA) is employed to find the optimal parameters of SVM firstly, and then the cross - validation (CV) method is employed to estimate the classification accuracy of the GSA-SVM model. Two examples of internal stability of soils are presented to validate the predictive capability of the proposed GSA-SVM model. In addition to verify the effectiveness of the proposed GSA-SVM model, the predictions from the proposed GSA-SVM model were compared with those from the traditional back propagation neural network (BPNN) model. The results showed that the proposed GSA-SVM model is a feasible and efficient tool for assessing the internal stability of soils with high accuracy.

• Journal of Climate Change Research
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• v.5 no.4
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• pp.291-300
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• 2014

In this study, we investigated the activity data and basic data of the surface of the water within the ship to be operated by lakes and rivers inland. In this study previously, there was no survey activity data of Ferry and Cruise ship in Korea. In order to ensure the basic data and development of measures to reduce efficiently by local governments, these studies should be performed. Therefore, in the present study was survey the activity data such as cruising time and engine load factor and the specifications of the vessels. As a result, by analyzing the cruising pattern according to the area and the purpose of the cruise, to calculate the emissions of greenhouse gases.

• Atmosphere
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• v.28 no.4
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• pp.393-402
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• 2018

This study investigated future changes in the Arctic permafrost features and related biogeochemical alterations under global warming. The Community Land Model (CLM) with biogeochemistry (BGC) was run for the period 2005 to 2099 with projected future climate based on the Special Report on Emissions Scenarios (SRES) A2 scenario. Under global warming, over the Arctic land except for the permafrost region, the rise in soil temperature led to an increase in soil liquid and decrease in soil ice. Also, the Arctic ground obtained carbon dioxide from the atmosphere due to the increase in photosynthesis of vegetation. On the other hand, over the permafrost region, the microbial respiration was increased due to thawing permafrost, resulting in increased carbon dioxide emissions. Methane emissions associated with total water storage have increased over most of Arctic land, especially in the permafrost region. Methane releases were predicted to be greatly increased especially near the rivers and lakes associated with an increased chance of flooding. In conclusion, at the end of $21^{st}$ century, except for permafrost region, the Arctic ground is projected to be the sink of carbon dioxide, and only permafrost region the source of carbon dioxide. This study suggests that thawing permafrost can further to accelerate global warming significantly.

• Journal of Drive and Control
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• v.16 no.1
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• pp.1-6
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• 2019

The use of micro bubbles in industrial fields has been increasing in the recent years., particularly micro-bubble sterilization and water purification effects. Various methods have been developed for the generation of micro-bubbles. Depending on the method of generating bubbles, the micro-bubbles can be roughly classified into saturation molding, cavitation and rotation flow types. The objective of this study was to use ventilated tube type as a method of generating micro-bubbles in order to purify large amount of water quality such as lakes and reservoirs. This method shows a difference in efficiency in which micro-bubbles are generated depending on the contact ratio of gas to liquid. The study also investigated the optimal gas liquid contact ratio by applying various orifice methods and investigated the optimum condition of micro-bubble generation by gas Based on this, a technology to develop a micro-bubble generator with a venturi type nozzle shape that has a high water purification effect was developed.

• Journal of Integrative Natural Science
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• v.15 no.3
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• pp.111-122
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• 2022

The purpose of this study was to investigate the ecological impact of wetlands by changing the species diversity of benthic macroinvertebrates and birds following the creation of an artificial wetland with a size of 30 m*30 m on bare land in reclaimed land in Haenam-gun, Korea. We investigated monthly fauna of benthic macroinvertebrates and birds in and outside wetlands and physicochemical indicators for 7 months from March to September 2014. During the study period, the water temperature and dissolved oxygen levels were consistently higher in wetlands than lakes. Many species of benthic macroinvertebrates were observed in summer (16 species in July) due to seasonal effects, and the species diversity index was highest in July and then gradually decreased. Thirteen species of birds were observed in March, 6 species in April, 5 species in July, and 1 species in June, where most winter birds and migratory birds were observed around wetlands in spring. The species diversity index also decreased after being high in July except for spring. This suggests that the abiotic environment in the wetland can be improved by creating an artificial wetland in the reclaimed land, and the increase in benthic macroinvertebrates can ultimately be a basic direction to restore the wetland ecosystem in the reclaimed land.

• Journal of Korean Society on Water Environment
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• v.39 no.3
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• pp.215-222
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• 2023

Zooplankton are primary consumers in the food web connecting primary producers and predators such as small fish, playing an important role in energy transfer in aquatic ecosystems. Therefore, it is essential to understand the zooplankton community structure in material cycle and energy flow in aquatic ecosystems. Zooplankton in large rivers with a low flow rate would distribute vertically as in lakes. In this study, we collected zooplankton by surface water filtration and vertical haul method with 64 ㎛-mesh plankton net at three stations (ND-1, ND-2, ND-3) in Nakdong River fortnightly from June 2018 to December 2019. Species composition and individual densities were analyzed. All three stations showed differences in relative abundance of zooplankton groups between surface water and vertical integrated water, with the largest difference shown in the deepest station, ND-2. In vertically integrated water at ND-2, the relative abundance of rotifera was low by a maximum of 25% and that of cladocera was high by a maximum of 22% compared to surface water samples. These results indicate that surface water filtration method is not enough to represent the community structure of zooplankton compared to the vertical haul method in large rivers.

• Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.23-34
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• 2024

While scientific information on the spatial variation of soda lake Microalgae is important to limnological studies, little information was reported from the Ethiopian Rift Valley Lake, Lake Chitu. This study aimed to understand the spatial distribution of the dominant Microalgae taxa in Lake Chitu, Ethiopia. The collection of samples and in situ measurements of some physico-chemical parameters were recorded at three sites for one cycle in November 2021. Fourteen species or genera of Microalgae were identified. Among those, Bacillariophyta were the most important with regard to species abundance and the rarest in species richness. Cyanophyta were the second-most important group in terms of species richness and rarity. Comparatively, all microalgae taxa were rare at both the anthropogenic areas (AA) and the flooding area (FA), which could be mainly due to intensive human and animal intervention and associated with extreme turbidity. Among Cyanophyta, Chroococcus minutus, Microcystis aeruginosa, and Spirulina platensis/fusiformis were predominant at both AA and FA, revealing their adaptation to less clear water and pollution. But S. platensis/fusiformis attained the highest abundance at the FA, indicating their preference for water in a highly nutrient-enriched area. We concluded that the spatial variation of microalgae diversity in relation to water quality parameters has implications for the importance of microalgae as a baseline indicator of water quality assessment tools in lakes.