• 한국물환경학회지
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• 제26권5호
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• pp.860-870
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• 2010

Long term monthly monitoring data showed that the water quality of streams flowing into Lake Paldang has been improved by various strategy for water. However, the effect of quality on Lake Paldang is still insufficient because of nonpoint source from watershed. In order to evaluate quantifying methods for pollution source and make a suggestion on improvements, Storm Water Management Model (SWMM) was constructed by using data set from the water quality and streamflow monitoring network in the Kyoungan watershed for Total Maximum Daily Loads (TMDLs). Load duration curve (LDC) based on the result of the Kyoungan watershed SWMM indicated that the water quality criterion on $BOD_5$ was often exceeded in up-stream than down-stream. From flowrate-load correlation curve, SS load significantly increased as streamflow increases. 75.3% of streamflow and 62.1% of $BOD_5$ loads is discharged especially in the zone of high flows, but monitoring data set didn't provide proper information about the conditions and the patterns associated with storm events. Therefore, it is necessary to acquire representative data set for comparing hydrograph and pollutograph through monitoring experimental watershed and to establish methods for quantifying point and nonpoint source pollutant loads.

• 한국물환경학회지
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• 제27권2호
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• pp.159-166
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• 2011

The use of land cover was sharply changed during 1975~2007 in the Kyungan watershed $(561.12 km^2)$. The changes occurred over an area of more than $227.65 km^2$ during the overall period at changing rates of 1.04% per year for water area, 1.79% per year for residential area, 2.99% per year for bare area, 3.03% per year for wetland area, 3.04% per year for grass area, 0.87% per year for forest and 2.32% per year for agriculture area. Water, residential, bare and wetland areas increased, while grass, forest and agriculture areas decreased during the last 32 years. BOD concentrations of representative sites for each sub-watershed continuously increased until the early 2000s as residential area increased with the highest discharged load, but decreased after the mid 2000s except upper Kyungan watershed. Such decline appears to be associated with the planning of Total Maximum Daily Load management for Gwangju city and expansion of waste water treatment plant. It is necessary to control land use/cover changes of the upper watershed and to prepare appropriate watershed management system for improvement in river environment including water quality, stream flow and bio-diversity.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권11호
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• pp.3030-3049
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• 2023

With the development and wide application of hybrid network computing modes like cloud computing, edge computing and fog computing, the customer service requests and the collaborative optimization of various computing resources face huge challenges. Considering the characteristics of network environment resources, the optimized deployment of service resources is a feasible solution. So, in this paper, the optimal goals for deploying service resources are customer experience and service cost. The focus is on the system impact of deploying services on load, fault tolerance, service cost, and quality of service (QoS). Therefore, the alternate node filtering algorithm (ANF) and the adjustment factor of cost matrix are proposed in this paper to enhance the system service performance without changing the minimum total service cost, and corresponding theoretical proof has been provided. In addition, for improving the fault tolerance of system, the alternate node preference factor and algorithm (ANP) are presented, which can effectively reduce the probability of data copy loss, based on which an improved cost-efficient replica deployment strategy named ICERD is given. Finally, by simulating the random occurrence of cloud node failures in the experiments and comparing the ICERD strategy with representative strategies, it has been validated that the ICERD strategy proposed in this paper not only effectively reduces customer access latency, meets customers' QoS requests, and improves system service quality, but also maintains the load balancing of the entire system, reduces service cost, enhances system fault tolerance, which further confirm the effectiveness and reliability of the ICERD strategy.

• 대한환경공학회지
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• 제36권12호
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• pp.813-820
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• 2014

대전 3대하천을 대상으로 차집관로와 하수처리시설 증설로 인한 도시하천의 수질변화의 특성을 분석하였다. 지난 10년 동안 최고 수질에서 최저 수질의 차이가 가장 큰 하천지점은 하수처리시설 하류부인 갑천5(신구교) 지점이다. 반면에 최근 수질은 이 지점이 다른 지점보다 수질이 불량한 것은 하수처리시설의 방류수 영향이다. 하수처리시설 상류부에서는 대전천이 유기물질의 오염감소에서 다른 지점보다 비교적 양호한 지점인데 이는 차집관로의 유지관리 투자에 기인한 것으로 보인다. 최근 3대하천 수질은 하천수질기준치와 비교하였을 때 대부분 수질항목은 기준치 이내로 적합하였으나 상류지점인 대전천, 유등천, 갑천3 지점의 총인은 기준치에 못 미치므로 하수처리시설 상류부가 하류부보다 차집관로의 유지관리가 더 필요하다. 하수처리시설의 방류수 수질이 하천 수질오염총량관리 지점의 목표수질에 악영향을 주기 쉬우므로 하수처리시설 유지관리의 효율성이 적극 요구된다.

• Membrane and Water Treatment
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• 제10권5호
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• pp.339-352
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• 2019

Long term water quality change was analyzed to evaluate the effect of the Total Maximum Daily Load (TMDL) policy. A trend analysis was performed for biochemical oxygen demand (BOD) and total phosphorus (TP) concentrations data monitored at the outlets of the total 41 TMDL unit watersheds of the Nakdong River in the Republic of Korea. Because water quality data do not usually follow a normal distribution, a nonparametric statistical trend analysis method was used. The monthly mean values of BOD and TP for the period between 2004 and 2015 were analyzed by the seasonal Mann-Kendall test and the locally weighted scatterplot smoother (LOWESS). The TMDL policy effect on the water quality change of each unit watershed was analyzed together with the results of the trend analysis. From the seasonal Mann-Kendall test results, it was found that for BOD, 7.8 % of the 41 points showed downward trends, 26.8 % and the rest 65.9% showed upward and no trends. For TP, 51.2% showed no trends and the rest 48.8% showed downward trends. From the LOWESS analysis results, TP began to decrease in most of the unit watersheds from mid-2010s when intensive chemical treatment processes were introduced to existing wastewater treatment plants. Overall, for BOD, relatively more points were improved in the main stream compared to the points of the tributaries although overall trends were mostly no trend or upward. For TP, about half of the points were improved and the rest showed no trends.

• Journal of Nutrition and Health
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• 제41권7호
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• pp.645-657
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• 2008

This study was conducted to study the relationship between food intakes, glycemic index (GI), glycemic load (GL), and body weight with high school boys residing in Seoul. The subjects of 329 boys were divided into normal weight group (BMI < $23\;kg/m^2$, n = 212) and overweight group (BMI ${\geq}\;23\;kg/m^2$, n = 117) by body mass index (BMI). The food intakes data obtained by the 3-day food record were analyzed by Can pro 3.0 software. Anthropometric measurements and physical activities were collected from each subject. Daily dietary glycemic index (DGI) and dietary glycemic load (DGL) were calculated from the 3-day food record. Body weights and BMI of normal weight group were 58.8 kg and $19.9\;kg/m^2$ and those of overweight group were 79.2 kg and $26.8\;kg/m^2$, which were significantly different between two groups (p < 0.05). Total food and animal food intakes of normal weight group were significantly higher than overweight group (p < 0.05), and vegetable food and other food intakes of normal weight group showed higher than overweight group. All nutrient intakes of normal weight group were higher than overweight group. Dietary fiber, calcium, potassium and folate intakes of normal weight group and overweight group were under 65% of the dietary reference intakes (DRIs). Major food sources of energy intake for both groups were rice, pork and instant noodle in order. Mean adequacy ratio (MAR), an index of overall dietary quality were 0.83 in normal weight group and 0.79 in overweight group, which showed significantly higher in normal weight group than overweight group (p < 0.05). Mean daily dietary GI of normal weight group and overweight group were 67.7 and 68.2, respectively. Mean daily dietary GL of normal weight group and overweight group were 214.6 and 202.7, respectively, and which was significantly different between the two groups (p < 0.05). Major food sources contributed to DGI and DGL were rice ($\geq$ 55%) in both groups. DGI and DGL were not significantly correlated with anthropometric data. Activity adjusted to energy intake was negatively correlated with percentage of body fat (r = -0.1308, p < 0.01) and that was positively correlated with height (r = 0.1227, p < 0.05) and lean body mass (r = 0.1351, p < 0.05).

• 한국물환경학회지
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• 제23권5호
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• pp.766-775
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• 2007

The use of toxic chemicals was extended as the industry in Korea has grown dramatically during the last three decades. However, list of toxic substances and limit concentrations in the water environment are not consistent within management of ambient water, drinking water and industrial effluent. This article suggests the systematic framework to classify toxic substances in the water environment and deriving their effluent limits. The most important factor for decision-making to classify toxic substances is whether their concentrations in the water environment are higher than the reference concentrations, estimated by considering human health risk and ecological risk. Using a risk-based reference concentration, the ambient water quality criterion, it is possible to derive the regulatory limit concentrations of toxic substances in drinking water and in industrial effluent. The goal concentrations in the effluent, which guarantee the human and ecological safety, should be determined with scientific investigation, balancing environmental benefit and economical effect, considering availability of treatment technology and identifying characteristics of wastewater from different industries.

• 한국환경과학회지
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• 제26권8호
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• pp.939-953
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• 2017

For the development of flow duration curves for the management of 41 Total Maximum Daily Load (TMDL) units of the Nakdong River basin, first, an equation for estimating daily flow rates as well as the level of correlation (correlation and determination coefficients) was extrapolated through regression analysis of discrete (Ministry of Environment) and continuous (Ministry of Land, Infrastructure and Transportation) measurement data. The equation derived from the analysis was used to estimate daily flow rates in order to develop flow duration curves for each TMDL unit. By using the equation, the annual flow duration curves and flow curves, for the entire period and for each TMDL unit of the basin, were developed to be demonstrated in this research. Standard flow rates (abundant-, ordinary-, low- and drought flows) for major flow duration periods were calculated based on the annual flow duration curves. Then, the flow rates, based on percentile ranks of exceedance probabilities (5, 25, 50, 75, and 95%), were calculated according to the flow duration curves for the entire period and are suggested in this research. These results can be used for feasibility assessment of the set values of primary and secondary standard flow rates for each river system, which are derived from complicated models. In addition, they will also be useful for the process of implementing TMDL management, including evaluation of the target level of water purity based on load duration curves.

• 한국지하수토양환경학회지:지하수토양환경
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• 제12권3호
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• pp.1-9
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• 2007

수질오염 총량제가 시행됨에 따라 깨끗한 수자원을 확보하기 위한 오염퇴적물의 관리 및 처리 필요성이 더욱 높아지고 있다. 본 논문에서는 오염퇴적물의 발생원과 오염퇴적물이 수질에 미치는 영향을 살펴보고, 오염퇴적물의 관리방향을 제시하였다. 오염퇴적물을 처리하기 위한 공법으로 준설공법과 자연정화법, 현장고정화/안정화, 생물학적 현장처리, 화학적 현장처리 공법에 대하여 요약 제시하였다. 또한 새롭게 대두되고 있는 캡핑공법을 소개하고, 오염퇴적물 처리를 위한 복합공법의 적용에 대한 개념을 제시하였다.

• 대한안전경영과학회지
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• 제15권2호
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• pp.167-184
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• 2013

A cross docking operation involves multiple inbound trucks that deliver items from suppliers to a distribution center and multiple outbound trucks that ship items from the distribution center to customers. Based on customer demands, an inbound truck may have its items transferred to multiple outbound trucks. Similarly, an outbound truck can receive its consignments from multiple inbound trucks. The objective of this study is to find the best truck spotting sequence for both inbound and outbound trucks in order to minimize total operation time of the cross docking system under the condition that multiple visits to the dock by a truck to unload or load its consignments is allowed. The allocations of the items from inbound trucks to outbound trucks are determined simultaneously with the spotting sequences of both the inbound and outbound trucks.