• Journal of Wetlands Research
• /
• v.17 no.4
• /
• pp.428-435
• /
• 2015

Constructed wetlands (CWs) have been accepted as an attractive and economic alternative to a variety of pollution control and provided potentially valuable wildlife habitat in urban and suburban areas, as well as esthetic value within the local natural environment. CWs are known eco-friendly technology to solve the problem of the climate change and urbanization issues. Numerous studies have been published on the various aspects of a CW. However, there are current limitations about the CW operations such as few design guidelines, poor performance results regarding the simple construction. Therefore, the objective of this research was to suggest an appropriate design and maintenance guidelines for a CW by thorough investigation of site monitoring results. The research also concentrated in redefining and reclassifying CWs, based on literatures made by the Ministry of Environment (MOE) and other organizations. Investigation at 43 CWs in Korea was performed by using collected data and by performing site survey from 2013 to 2014. Based on the results, the best practices among the investigated CWs provided water treatment, wildlife habitat, environmental education, and leisure. Also these CWs conducted a regular maintenance such as vegetation, sediment dredging and cleaning of facilities. Results obtained are intended for use by academics and any organizations involved in CW management.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2010.05a
• /
• pp.1457-1460
• /
• 2010

최근 기후변화로 인해 태풍 등과 같은 집중성 강우가 많이 발생하고 있고, 강우시 유출 등으로 인한 유역내 발생하는 토양침식으로 인해 유역의 하천을 비롯하여 유출구에서의 탁수 및 유사 발생 문제는 우리나라 뿐만 아니라 전 세계적으로 심각한 환경문제로 대두되고 있다. 강우시 유역에서 발생하는 이러한 탁수문제를 효과적으로 해결하기 위하여 여러 최적관리기법 (Best Management Practices, BMPs) 들이 제안되어왔다. 본 연구의 목적은 볏짚매트 사용으로 인한 토양유실 저감 실측자료를 바탕으로 볏짚매트를 다양한 경사지 밭에 적용하였을 경우 유역에서의 토양유실 저감효과를 평가하기 위한 모델링 기법을 개발하는데 있다. 볏짚 매트의 효과를 Soil and Water Assessment Tool (SWAT) 모형으로 모의하기 위해서는 볏짚매트의 효과를 모형에서 반영할 수 있는 인자를 선택하여 최적의 인자값을 산정해야 한다. 본 연구에서는 유사 저감 효과 실험 결과를 VFSMOD-W 모형을 이용하여 USLE P 인자값을 도출하였으며, 경사도에 따른 USLE-P 값을 산정하여, SWAT 모형에 입력자료로 사용하였다. 분포형 모형과는 달리 준분포형 모형인 SWAT 모형은 소유역내 수문학적 반응단위별로 유출, 유사, 그리고 비점오염 발생을 평가하는데 이때 Hydrologic Response Unit (HRU)의 지형정보가 활용된다. 이 지형정보는 SWAT 유사 평가시 매우 민감한 변수중의 하나이기 때문에 유역 단위 유사 평가시 정확한 지형자료의 입력이 요구된다. 그러나 SWAT 모형은 소유역내 HRU의 경사도 및 경사장을 직접 산정하지 않고, 소유역의 평균경사도를 기준으로 하여 산정된 경사도를 소유역내 모든 HRU에 동일하게 적용하는 단점이 있다. 본 연구에서는 준분포 모형인 SWAT 모형의 단점을 개선하기 위하여 SWAT Spatially Distributed (SD)-HRU를 적용하였다. 이를 통해 다양한 경사지 밭에서의 볏짚매트의 효과를 분석할 수 있게 되었다. 볏짚매트 미적용시 모의 기간내 유사량 총합은 74,954.42 ton 이고, 월평균 유사량은 814.72 ton 으로 산정되었고, 볏짚매트를 적용하였을 경우 모의 기간내 (2000년 1월 - 2007년 8월) 유사량 총합은 48,460.55 ton 이고, 월평균 유사량은 526.75 ton 으로 볏짚매트를 적용하지 않았을 때보다 약 35.35 % 저감된 값을 보였다. SD-HRU를 적용하고 각 농경지의 경사도에 따라 USLE P 값을 수정하여 볏짚매트에 의한 효과를 분석하였을 때, 볏짚매트를 적용하지 않았을 때 보다 볏짚매트를 적용하였을 때 모의 기간내 약 35% 정도의 유사량이 감소된 것을 알 수 있었다. 본 연구결과에서 보여주는 바와 같이 고랭지 지역에서의 영농활동 시 볏짚매트를 설치한다면 강우시 발생하는 토양유실을 효과적으로 저감시킬 수 있을 것이라 판단된다.

• Journal of Environmental Policy
• /
• v.9 no.1
• /
• pp.83-107
• /
• 2010

Urbanized environments are constructed to estimate peak flow and cost savings in response to possible BMP allocation at a watershed scale. The main goal is to explore the proper allocation of sub-watershed level BMPs for peak flow attenuation at a watershed scale. Since several individual site scale BMPs work as a form of aggregated BMPs at a sub-watershed scale, it is a question as to how to properly allocate the sub-watershed level BMPs at a watershed scale. The Hydrological Simulation Program-FORTRAN (HSPF) is set up for a hypothetically urbanized watershed. A peak flow is determined to be the primary variable of interest and targeted to characterize the spatial distribution of aggregated BMPs. Construction cost of a regional pond forms the basis of the economic valuation. The results indicate that when total size of BMPs is constant in the entire watershed, (1) it is most effective to have aggregated BMPs in some upper sub-watersheds while the BMPs in either the mainstem sub-watershed or a single sub-watershed are the least effective choices for peak flow attenuation at a watershed scale; (2) savings exist between allocation differences and reduced peak flow increases cost savings. The largest saving is found in the strategy of aggregated BMPs in some upper sub-watersheds. These findings, however, call for follow-up site specific case studies revisiting the watershed scale impacts of BMP allocation. Then, it will be argued that location and extent of decentralization are considerable policy variables for an alternative stormwater management policy at a watershed scale.

• Environmental and Resource Economics Review
• /
• v.28 no.4
• /
• pp.527-556
• /
• 2019

In Korea, nearly 100 billion won is spent annually under the name of energy voucher on 600,000 households for the last five years, and this is a unique case and hard to monitor worldwide. Therefore, no studies have been conducted to assess impacts of the energy voucher on energy consumption and cost burden alleviation for beneficiaries. This paper aims to demonstrate the effectiveness of energy vouchers in terms of energy expense. The propensity score matching was conducted on samples of low-income households based on the Korea Welfare Panel. Then, simple Difference-In-Differences and Fixed-Effect Difference-In-Differences models were applied to estimate the effect of energy vouchers. In results, the beneficiaries of energy vouchers would spend an additional 4,371~4,870 won per month on energy consumption. The ratio is equivalent to 51.9~57.7 percent of the aid, which is also the highest when compared with 23~56 percent of U.S. Food Stamp. In terms of energy welfare, voucher payment could become one of the best management practices. However, identifying the blind spots as non-reciprocal households and expanding the differential support mechanism that reflects the energy consumption environment should be solved in the future.

• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.1
• /
• pp.23-31
• /
• 2012

Measures against non-point sources pollution in Saemangeum watershed should be established to control water quality of Saemangeum lake, because non-point sources pollution discharge portions of BOD (Biological Oxygen Demand) and TP (Total Phosphorous) in the watershed were 68.4 and 61.4%, respectively. In this study, target regions for the non-point sources pollution control were selected to apply BMP (Best Management Practices) for the agricultural area of Saemanguem watershed in terms of TP that caused eutrophication at the lake. Target regions were selected by the NPSI (Non-point source index) that was calculated by the total 12 indexes at the steps of non-point source production, emission and outflow. Weights of the indexes were determined by the watershed management experts oriented AHP (Analytic Hierarchy Process) analysis. The target region was selected at the unit of Korean basic administrative district 'Dong/Li'. At the results of NPSI calculations through the GIS (Geographical Information System) tools, two sets of 5 regions were selected in the Man-kyung River and Dong-gin River. The main reason for the selected target regions was livestock activity in the district. The results of this study can be useful for implementing the reduction projects of agricultural non-point sources pollution to control water quality in Saemangeum lake.

• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.6
• /
• pp.451-459
• /
• 2014

The development and reduction scheme under implementation plan of TMDLs were performed in the Jinwi watershed including 8 cities (Gunpo, Yongin, Suwon, Anseong, Osan, Uiwang, Pyeongtaek and Hwaseong) since 2012. Progress of the annual development schemes was faster than the reduction schemes in most of the cities during the planning period. Main load reduction methods included establishment and enlargement of sewage treatment plants, resources of livestock excretions, and introduction of best management practices of non-point source pollution. Especially, reduction load using recycling and composting of livestock excretions comprised 34.1% of all reduction load. It is necessary to implement methodical development and reduction scheme for making of successful performance of TMDLs and water quality improvement in the Jinwi watershed.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.19 no.4
• /
• pp.270-279
• /
• 2017

Regional assessment of crop productivity using a gridded simulation approach could aid policy making and crop management. Still, little effort has been made to develop the systems that allows gridded simulations of crop growth using ORYZA 2000 model, which has been used for predicting rice yield in Korea. The objectives of this study were to develop a series of data processing modules for creating input data files, running the crop model, and aggregating output files in a region of interest using gridded data files. These modules were implemented using C++ and R to make the best use of the features provided by these programming languages. In a case study, 13000 input files in a plain text format were prepared using daily gridded weather data that had spatial resolution of 1km and 12.5 km for the period of 2001-2010. Using the text files as inputs to ORYZA2000 model, crop yield simulations were performed for each grid cell using a scenario of crop management practices. After output files were created for grid cells that represent a paddy rice field in South Korea, each output file was aggregated into an output file in the netCDF format. It was found that the spatial pattern of crop yield was relatively similar to actual distribution of yields in Korea, although there were biases of crop yield depending on regions. It seemed that those differences resulted from uncertainties incurred in input data, e.g., transplanting date, cultivar in an area, as well as weather data. Our results indicated that a set of tools developed in this study would be useful for gridded simulation of different crop models. In the further study, it would be worthwhile to take into account compatibility to a modeling interface library for integrated simulation of an agricultural ecosystem.

• Journal of Navigation and Port Research
• /
• v.42 no.1
• /
• pp.67-78
• /
• 2018

This paper aims to investigate the nature of Customer Relationship Management (CRM) in liner shipping industries, study the organization's general characteristics which could help to promote such CRM practices, and analyze the relationship between the CRM and the organization's effectiveness. The result of analysis shows that the organizational characteristics which affect the CRM most in shipping industries are the market orientation and the CEO's support. In particular, the CRM was proven to have significant impact on employee satisfaction, service competitiveness enhancement, financial performance, customer satisfaction and the repurchase intention of the customers. This study also suggests that the CRM of liner shipping industries should be enforced comprehensively in synchronization with organizational characteristics, such as organizational culture and organizational systems. Based on such organizational characteristics, the noted CRM strategies were justified to have significantly impacted the overall management performance of the organizational performance of shipping industries and the customer's satisfaction and repurchase intention. This study would be appreciated as a meaningful analysis on the CRM in liner shipping industries which pursues the best interests of both shipping companies and customers.

• Journal of KIISE:Computing Practices and Letters
• /
• v.13 no.4
• /
• pp.231-239
• /
• 2007

This paper presents the trade-off relationship between area and performance in the hardware design space exploration for the Korean national standard 128-bit block cipher algorithm SEED. In this paper, we compare the following four hardware design types of SEED algorithm : (1) Design 1 that is 16 round fully pipelining approach, (2) Design 2 that is a one round looping approach, (3) Design 3 that is a G function sharing and looping approach, and (4) Design 4 that is one round with internal 3 stage pipelining approach. The Design 1, Design 2, and Design 3 are the existing design approaches while the Design 4 is the newly proposed design in this paper. Our new design employs the pipeline between three G-functions and adders consisting of a F function, which results in the less area requirement than Design 2 and achieves the higher performance than Design 2 and Design 3 due to pipelining and module sharing techniques. We design and implement all the comparing four approaches with real hardware targeting FPGA for the purpose of exact performance and area analysis. The experimental results show that Design 4 has the highest performance except Design 1 which pursues very aggressive parallelism at the expanse of area. Our proposed design (Design 4) shows the best throughput/area ratio among all the alternatives by 2.8 times. Therefore, our new design for SEED is the most efficient design comparing with the existing designs.

• Journal of Soil and Groundwater Environment
• /
• v.22 no.6
• /
• pp.74-84
• /
• 2017

Soil erosion is often extreme in Korea due to high rainfall intensities and steep slopes, and climate change has also increased the risk of erosion. Despite its significane, erosion-induced soil organic carbon (SOC) emission and water resource loss are not well understood, along with the lack of an integrated surface soil erosion protection policy. Therefore, to design adequate protection policies, land users, scientists, engineers and decision makers need proper information about surface soil and watershed properties related to greenhouse gas emission potential and water conservation capability, respectively. Assuming the total soil erosion of $346Tg\;yr^{-1}$, soil organic matter (SOM) content of 2% (58% of SOM is SOC), and mineralization rate of 20% of the displaced carbon, erosion-induced carbon emission could reach $800Gg\;C\;yr^{-1}$. Also the available water capacity of the soil was estimated to be 15.8 billion tons, which was 14 times higher than the yearly water supply demand in Seoul, Korea. Therefore, in order to prevent of soil erosion, this study proposes a three-stage plan for surface soil erosion prevention: 1) classification of soil erosion risk and scoring of surface soil quality, 2) selection of priority areas for conservation and best management practices (BMP), and 3) application of BMP and post management.