• Journal of Korea Water Resources Association
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• v.44 no.10
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• pp.809-817
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• 2011

We analyzed various cost components for approximately 40 small-scale island desalination plants operated by K-water. A significant factor affecting desalination cost was found, and we proposed a way to reduce desalination costs. All plants considered were reverse osmosis (RO) facilities. TDS concentrations of feed water varied from less than 1,000 mg/L (practically considered freshwater) to over 30,000 mg/L (nearly seawater). Analysis of desalination costs from 2005 to 2009 indicated that maintenance, labor, and energy were the three biggest components that accounted for 50.6%, 36.9% and 7.8%, respectively. It was well known that TDS of feed water directly affected energy needed for RO process. In this study we found that maintenance cost was also directly related to feed water TDS. This finding indicated that lowering feed water TDS might result in significant desalination cost reduction.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.4
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• pp.299-315
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• 2020

Tuna fisheries were applied to an integrated ecosystem-based fishery risk assessment method using indexes of target species status, inhabited species in a target ecosystem, habitat quality and socio-economic benefit of affected fisheries. This study suggested more effective and efficient management measures to break away from traditional management methods, such as limitation of catch and fishing effort. The results presented that the objective risk index (ORI_S) on sustainability of bigeye and yellowfin tunas by purse seine fishery was estimated high due to the high catch ratio of small fishes. The ORIs of biodiversity (ORI_B) and habitat quality (ORI_H) of purse seine fishery were also estimated at a high level from using fish-aggregating devices (FAD). However, due to skipjack tuna's high catches, the ORI of socio-economic benefit (ORI_E) was estimated at a very low level. Due to the high bycatch rate, ORI_B was high, and ORI_S and ORI_H were evaluated at a low level in longline fishery. Due to strengthern of fishing restrictions and increase of fishing costs, the ORI_E was assessed to be very high. The ecosystem risk index (ERI) for two tuna fisheries was assessed low, but the overall FAD management by purse seine fishery is necessary at the ecosystem level.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1286-1294
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• 2011

This paper reviews the future directions and perspectives on the soil environmental researches in the 21 century. Previously, the principal emphasis of soil environmental researches had put on the enhancement of food and fiber productions. Beside the basic function of soil, however, the societal needs on soil resources in the 21st century have demands for several environmental and social challenges, occurring regionally or globally. Typical global issues with which soil science should deal include food security with increasing agronomic production to meet the exploding world population growth, adaptation and mitigation of climate change, increase of the carbon sequestration, supply of the biomass and bioenergy, securing the water resource and quality, protection of environmental pollution, enhancing the biodiversity and ecosystem health, and developing the sustainable farming/cropping system that improve the use efficiency of water and agricultural resources. These challenges can be solved through the sustainable crop production intensification (SCPI) or plant welfare concept in which soil plays a key role in solving the abovementioned global issues. Through implementation of either concept, soil science can fulfill the goal of the modern agriculture which is the sustainable production of crops while maintaining or enhancing the ecosystem function, quality and health. Therefore, directions of the future soil environmental researches should lie on valuing soil as an ecosystem services, translating research across both temporal and spatial scales, sharing and using data already available for other purposes, incorporating existing and new technologies from other disciplines, collaborating across discipline, and translating soil research into information for stakeholders and end users. Through the outcomes of these approaches, soil can enhance the productivity from the same confined land, increase profitability, conserve natural resource, reduce the negative impact on environment, enhance human nutrition and health, and enhance natural capital and the flow of ecosystem services. Soil is the central dogma, final frontier and new engine for the era of sustainability development in the $21^{st}$ century and thus soil environmental researches should be carried according to this main theme.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.352-352
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• 2020

통합물관리 (IWRM; Integrated Water Resources Management)란 생태계의 지속가능성(sustainability)을 해치지 않으면서, 공평한 방법(equity)으로 경제·사회·복지를 극대화(efficiency) 할 수 있도록 물과 토지 및 관련 기타 자원들을 조화롭게 개발하고 처리하는 과정을 말한다. IWRM 패러다임은 전 세계적 및 국가별 물관리 상황에 따른 시대적 이슈에 따라 변천하고 있고 1992년 리우 정상회담 이후 물위기 극복을 위한 새로운 패러다임으로 정착, 물재해 심화에 따라 2000년대 물안보라는 국가 차원의 과제로 발전하였다. 이에 이미 전세계 국가의 68%이상이 도입중이며 모든 국가로 확산 중에 있다. 그러므로 본 연구에서는 향후 통합수자원관리 측면에서의 우즈베키스탄 내 업무와 환경을 분석하여 표준화된 수자원정보화 방향을 제시하고 통합물관리를 위한 통합물관리시스템을 개발하는 것을 목적으로 한다. 우즈베키스탄은 기본적으로 물관리 여건이 매우 불리한 물스트레스 국가로 분류되고 있다. 국가 내에서 필요로하는 대부분의 수자원이 양적으로 매우 부족하고, 강수량의 지역, 시기별 변동폭 역시 매우 크게 나타나고 있다. 또한 이용가능한 수자원을 작물재배가 가능한 시기에 농업용수로 80%이상을 취수하고 있어 심각한 물부족에 시달리고 있는 실정이다. 지정학적으로는 연강수량이 평균 400mm정도로 나타나고 있어 국내에서 생산되는 물 이외에는 국내를 통과하는 시르다리야, 아무다리야 강의 상류에 위치한 키르기즈스탄, 타지키스탄에서 생성된 물을 하천에서 취수하여 사용하고 있는 실정으로 제한된 수자원을 효율적, 합리적으로 이용하는 데 있어 관리기술의 개선이 필요하다. 수자원의 대부분은 수자원부에서 산하 관리조직을 통해 중앙에서 통제하에 관리하고 있으나 국가간, 지역별 용수배분, 갈등이 심하되고 있는 상태에 있으며 이러한 점을 해결하기 위한 상류-하류간 연계, 수량-수질간 연계, 지표수-지하수 연계 등을 위한 법적, 제도적 기반이 미흡한 상태이다. 이러한 우즈베키스탄 내 IWRM 도입의 필요성을 기반으로 통합물관리를 위한 시스템 구성요소를 도출하고 구축을 위해 고려해야 할 사항 및 발전방향을 본 연구를 통하여 제시하고자 한다.

• Journal of Korean Society on Water Environment
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• v.25 no.1
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• pp.26-36
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• 2009

Combined sewer system (CSS) has been built in the most urban areas across the nation. During dry weather conditions, CSS works fine. But during heavy rain storms, combined sewage frequently overflows into the stream. This study simulated the hydrologic cycle and pollutant loads (BOD, SS, TN and TP) in the Mokgamcheon watershed considering combined sewer overflows (CSOs). PC storm water management model (PCSWMM) was used for continuous simulation and CSOs are considered using the flow divider. Sensitivity analysis, calibration and verification for water quantity and quality are carried out. To verify CSOs, field measurements of CSOs are compared with simulated results. As a result, 41.3% of precipitation flows into the stream directly and 1.1% of water supply flows into stream as CSOs. 6.5% of BOD total loads, 12.0% of SS, 13.6% of TP, and 29.2% of TN are from CSOs. This result will be effective to the integrated watershed management for sustainability.

• Journal of Korea Water Resources Association
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• v.53 no.spc1
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• pp.827-832
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• 2020

The catchment management experiences of the Evian natural mineral water (NMW) bottling company were reviewed. Evian is among the leading brands of bottled NMW in France, exporting worldwide and becoming a role model for companies in many countries due to its long-term experiences in sustainably managing NMW source areas. Experiences of bottled water companies in France show that they are incessantly moving forward with proactive and advanced ideas to meet environmental challenges. For business sustainability, companies are dedicated to improving their environmental performance through effective and planned resource management. Evian has been working with the local community in a spirit of co-ownership to invent and preserve the water resource and fulfill its ambition of sustainable industrial functioning. The partnership aims to balance the protection of the NMW resource and sustainable agricultural development within the catchment.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.4
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• pp.297-306
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• 2014

Recently nano-materials are gaining more importance in the construction industry due to its enhanced energy efficiency, durability, economy, and sustainability. Nano-silica addition to cement based materials can control the degradation of the fundamental calcium-silicate-hydrate reaction of concrete caused by calcium leaching in water as well as block water penetration and therefore lead to improvements in durability. In this paper, the influence of synthesized nano silica from locally available rice husk on the mechanical properties and corrosion resistant properties of OPC (Ordinary Portland Cement) has been studied by conducting various experimental investigations. Micro structural properties have been assessed by conducting Scanning Electron Microscopy, Thermo gravimetry and Differential Thermal Analysis, X-Ray Diffraction analysis, and FTIR studies. The experimental results revealed that NS reacted with calcium hydroxide crystals in the cement paste and produces Calcium Silicate Hydrate gel which enhanced the strength and acts as a filler which filled the nano pores present in concrete. Hence the strength and corrosion resistant properties were enhanced than the control.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.2161-2166
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• 2009

It is important for 0-6 hour nowcasting to provide for a high-quality initial condition in a meso-scale atmospheric model by a data assimilation of several observation data. The polarimetric radar data is expected to be assimilated into the forecast model, because the radar has a possibility of measurements of the types, the shapes, and the size distributions of hydrometeors. In this paper, an impact on rainfall prediction of the data assimilation of hydrometeor types (i.e. raindrop, graupel, snowflake, etc.) is evaluated. The observed information of hydrometeor types is estimated using the fuzzy logic algorism. As an implementation, the cloud-resolving nonhydrostatic atmospheric model, CReSS, which has detail microphysical processes, is employed as a forecast model. The local ensemble transform Kalman filter, LETKF, is used as a data assimilation method, which uses an ensemble of short-term forecasts to estimate the flowdependent background error covariance required in data assimilation. A heavy rainfall event occurred in Okinawa in 2008 is chosen as an application. As a result, the rainfall prediction accuracy in the assimilation case of both hydrometeor types and the Doppler velocity and the radar echo is improved by a comparison of the no assimilation case. The effects on rainfall prediction of the assimilation of hydrometeor types appear in longer prediction lead time compared with the effects of the assimilation of radar echo only.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.449-461
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• 2023

The aim of this study was to conduct an ecosystem-based fishery risk assessment of tuna fisheries in the Western Indian Ocean. We selected gillnet, purse seine, hand line, baitboat, and longline fisheries as the target fisheries method, and selected longtail tuna (Thunnus tonggol), narrow-barred Spanish mackerel (Scomberomorus commerson), kawakawa (Euthynnus affinis), skipjack tuna (Katsuwonus pelamis), yellowfin tuna (T. albacares), bigeye tuna (T. obesus), albacore tuna (T. alalunga) and swordfish (Xiphias gladius) as the target species. The risk score for the size at the first capture in sustainability objective was high, especially, for the purse seine and baitboat fisheries using the fish aggregating devices (FADs). The risk score for the bycatch in the biodiversity objective was high for the gillnet fishery, and the gillnet fisheries using FADs showed high risks for the habitat quality objective due to the loss of the fishing gears. With regards to the socio-economic benefits objective, the risk score of the sales profits was low due to high sales of the tuna fisheries. The ecosystem risk score in the Western Indian Ocean was estimated to be moderate, although management is required for some of the indicators that have high-risk scores.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.210-210
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• 2022

This study evaluates Japan's Official Development Assistance (ODA) projects in Thailand from 2011 to 2013 by deploying the Sendai Framework for Disaster Risk Reduction (SFDRR) and the Organization for Economic Cooperation Development (OECD) evaluation criteria. Special attention is placed on disaster-related development assistance activities of Japan through reviewing long-term impacts of the projects. The Japan International Cooperation Agency (JICA) has played a crucial role in transferring Japan's experiences on disaster risk management to developing countries, including Thailand. The study highlights two flood risk management projects in Thailand with the support of JICA after the 2011 floods, namely the Project for the Comprehensive Flood Management Plan for the Chao Phraya River Basin and the Project for Flood Countermeasures for Thailand Agriculture Sector. The case studies demonstrate that the projects were efficiently and effectively conducted for meeting Thailand's needs and requirements. JICA provided multi-hazards risk analysis through scientific data as well as local knowledge. However, achievements of the project did not last for long because of a lack of Thai stakeholders' commitment and JICA's post-project management. It is concluded that a development agency should consider impacts and sustainability of flood risk management projects more carefully from the stage of planning, and the practical application of the knowledge, and technologies should also be monitored progressively after the completion of the project.