• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.337-347
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• 2018

The government has been operating residential improvement projects through the "Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents" as a type of a remedial measure for deteriorated residential areas. However, in recent years, the residential improvement projects have experienced difficulties due to the effects of various factors including the slowdown in economic growth. After observing the depression in a number of projects, various studies have been carried out to investigate the causality and improve the promotion of the residential improvement projects. In the trend of research, this study aims to analyze the effects of land and building characteristics on the improvement projects of Busan Metropolitan City. The dependent variables of the study represent different phases of improvement project as specified in the "Act on the Maintenance and Improvement of Urban Areas and Dwelling Conditions for Residents". The independent variables represent land and building characteristics which refer to the criteria used in the designation process of maintenance area according to the act. The empirical analysis uses the ordered logit model. The results from the analysis suggest that geographical condition, factors related to the number of union members, factors related to the parcel price and condition of a location have impact on the promotion of the improvement project. The results of the analysis show that majority of the factors are related to the economic feasibility of the projects. Residential improvement project is a part of urban planning projects that rehabilitates deteriorated residential environment, and it is closely associated with the quality of life of public. Accordingly, we hope that such projects are reasonable and take effective approach to those with urgent needs rather than to focus on profitability. Also, potential administrative and economical loss should be avoided by taking necessary planning measures in advance.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.771-781
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• 1997

In order to select an effective and appropriate evaluation method for the marine environmental protection and management, it is necessary to evaluate the present status of environmental conditions and to monitor and regulate the harzadous waste continuously. Among the evaluation methods that use benthic fauna, some graphical methods and biological index methods such as species abundance-biomass (SAB), Rank-frequency diagram (RFD), Abundance-Biomass comparison (ABC), log-normal distribution (LND), and Benthic Pollution Index (BPI) modified by Infaunal Trophic Index were used for the assessments of marine environment in the Inchon coastal area. Even though the graphic methods are convenient for easy glimpse of general trend of environmental condition but because they require sufficient ecological data, those methods do not fit for analysis or comparison of regional and detailed environmental condition. On the other hand, when BPI was applied, it was able to compare the spatial benthic conditions. Through considering the functional aspects of benthic fauna which can not be obtained in the cluster analysis, BPI was made it possible to measure or trace down the source of pollution. In the case of the environmental assessment result analyzed in Inchon coastal area, the north eastern part of Yongjongdo was more influenced by the pollution than the outer area of Inchon. The research indicates that especially Inchon harbor has been greatly affected.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.2
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• pp.137-142
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• 2011

This study was conducted to establish the optimal electrolyte and bismuth concentrations using bismuth film electrode in laboratory and to confirm the possibilities of using this operational condition for heavy metals monitoring in field. In lab test, heavy metal measurement was not accurate more than 600 ppb when heavy metal (Pb, Cd, Zn) range 100~1,000 ppb was measured with bismuth 2,000 ppb. So, bismuth and heavy metal was reacted about 1:1 with ASV method. In electrolyte test, 0.1 M acetate buffer (pH 4.5), 0.1 M chloroacetate buffer (pH 2.0), 0.1 M HCl (pH 2.0), 0.1 M $HNO_3$ (pH 2.0) was tested. As a results, 0.1 M acetate buffer was most suitable in ASV measurement with bismuth film electrode. In field application, Pb, Cd and Zn was measured respectively 36~45 ppb, 84~91 ppb, 90~98 ppb when heavy metal (Pb, Cd, Zn) 100 ppb was spiked in field sample. These results were identified of matrix effect in field sample, So relationship between heavy metal measurement and matrix effects will be studied.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.4
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• pp.204-209
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• 2015

The effluent limit of nickel from electroplating wastewater has been strengthened from 5 mg/L to 3 mg/L from 2014. However, currently applied treatment process for nickel plating wastewater is unable to meet the effluent limit, most of the treatment concept conducted by treatment plant is dilution with other metal bearing wastewater. This can cause very significant impact to the environment of nickel contamination. With this connection, the feasibility test has been conducted with the use of electrolysis by using sacrificial electrodes. Experiments were conducted in synthetic and electroless nickel plating wastewater. Optimal condition of current density, pH were derived from the synthetic wastewater. It was found that the removal efficiency of nickel exceeded 94% at the operation condition of at pH 9 and the current density of $1{\sim}2mA/cm^2$. At this conditions, the iron sludge was generated very low amount. However, it was unsuccessful to meet the effluent limit by applying these treatment conditions to the real electroplating wastewater. This can be explained due to the matrix effect of other metals and anions contained real electroplating wastewater. From the result of further study, the optimal conditions for the real wastewater treatment were found out to be at pH 9, current density $6{\sim}7mA/cm^2$, for 5 minutes of operating time. At these conditions, 88% removal of nickel was achieved, which results the residual nickel concentration was below 3 mg/L.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.2
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• pp.109-112
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• 2014

A porous ceramic which has fine porosity and small specific gravity is made with Cenosphere and Ball Clay under condition of $1,250^{\circ}C$ in calcination temperature and 30 minutes of calcination time. The average size of porous ceramic was about $2.5{\times}10^{-5}$ m and pores are well developed. The void-fraction of porous ceramic was 67.1% under the input of Cenosphere and Ball clay with the weight ratio of 100 to 5. However, as weight ratio of Ball Clay increased to 20, 40, 100, the void fraction decreased to 58.4, 56.7, 47% respectively. When the weight ratio of Cenosphere and Ball Clay was 100 to 100, the apparent density of porous ceramic was $1.04g/cm^3$. which is twice the density when the weight ratio of Ball Clay was 5. On the other hand, absorption rate decreased by at least 100%. In condition of weight ratio of Cenosphere and Ball Clay was 100 to 100, compressive strength of porous ceramic was 30 (MPa), improve by about 76% or more when the weight ratio of Ball Clay was 5.

• Journal of Wetlands Research
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• v.14 no.2
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• pp.237-242
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• 2012

In order to determine the ecological characteristics of Quercus serrata and Q. aliena, which are potential natural vegetation of riverine in Korea, we cultivated the seedlings of two oak species under light, soil moisture and nutrient gradients from April to October in glasshouse. Then, we measured aboveground, belowground and total plant biomass and analyzed the differences in growth between two oak species. The two oak species showed decreasing growth with lower light intensity, but reduction in growth of Q. aliena was greater than that of Q. serrata. Q. serrata and Q. aliena had a constant growth state under soil moisture gradients, but Q. aliena grew well more than Q. serrata in lower soil moisture gradient. As soil nutrient availability decreased, the growth of Q. aliena was greater than Q. serrata. These results mean that the growth of two oak species is not affected by soil moisture, but the part of growth in Q. serrata may be positively affected in lower soil moisture condition. Also, Q. serrata has strong shade tolerance and the ability to adapt high nutrient condition relative to Q. aliena. Thus, Q. serrata and Q. aliena will be advantageous for the growth in stream ecosystem due to high light availability, but Q. serrata will be distributed near the lowlands by the water environment. Also, because the two oak species need high soil nutrient, it is important to preserve herbaceous vegetation to prevent nutrients that flowed in the streams.

• Journal of Korea Water Resources Association
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• v.34 no.4
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• pp.347-356
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• 2001

Even though the increase of greenhouse gases such as $CO_2$ is thought to be the main cause for global warming, its impact on global climate has not been revealed clearly in rather quantitative manners. However, researches using Genral Circulation Model(GCM) has shown that the accumulation of greenhouse gases increases the global mean temperature, which in turn impacts on the global water circulation pattern. A climate predictive capability is limited by lack of understanding of the different process governing the climate and hydrologic systems. The prediction of the complex responses of the fully coupled climate and hydrologic systems can be achieved only through development of models that adequately describe the relevant process at a wide range of spatial and temporal scales. These models must ultimately couple the atmospheres, oceans, and lad and will involve many submodels that properly represent the individual processes at work within the coupled components of systems. So far, there are no climate and related hydrologic models except local rainfall-runoff models in Korea. The purpose of this research is to predict the change of temperature in Korean Peninsula using regional scale model(IRSHAM96 model) and GCM data obtained from the increasing scenarios of $CO_2$ Korean Peninsula increased by $2.5^{\circ}C$ and the duration of Winter in $lxCO_2$ condition would be shorter the $2xCo_2$ condition due to global warming.

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.319-326
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• 2014

Fish community was investigated in eutrophic Jeondae agricultural reservoir from April to November 2012. The food web structure of major fish species of Jeondae reservoir showed that due to serious organic pollution, the hyper-eutrophic condition with high chemical oxygen demand (COD), chlorophyll-a (Chl-a), total nitrogen (TN) and total phosphorus (TP), as estimated by stable isotope analysis. Total of 679 individuals were collected from the reservoir, and 9 species were identified. Interestingly, Lepomis macrochirus and Hemiculter eigenmanni known as less sensitive to pollution and water quality deterioration, dominated the reservoir, and their relative abundances were 38% and 27%, respectively. Further, the analysis of the stomach contents revealed that main food source of dominant L. macrochirus was high amount of zooplankton, which includes copepoda and cladocera, while Cyprinidae species mainly consumed organic particles with zooplankton preys. Stable isotope analysis also suggested that L. macrochirus, Carassiusauratus, Pseudorasboraparva, and H. eigenmanni are major zooplantivorous group in the Jeondae Reservoir.

• Ecology and Resilient Infrastructure
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• v.1 no.1
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• pp.19-24
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• 2014

The research evaluates the possibility of generating electricity using pyrite containing mine tailings, which are the major cause of acid mine drainage (AMD), by applying iron oxidizing bacteria (in this case, Acidithiobacillus ferrooxidans) and chemical fuel cell technology. The changes in the aqueous $Fe^{2+}$ concentration, which can represent an ionized form of pyrite, with an initial concentration of 9,000 mg/L were investigated during the 20 d growth period. Both the $Fe^{2+}$ and total iron (i.e., total $Fe^{2+}$)concentrations with or without A. ferrooxidans were observed. The $Fe^{2+}$ concentration decreased to about 6,000 mg/L, in the abiotic condition, while it decreased to about 400 mg/L in the biotic condition. The results showed that the increased $Fe^{2+}$ oxidation in the presence of A. ferrooxidans (i.e., catalytic ability of A. ferrooxidans) can be applied to electricity generation using pyrite containing mine tailings. In the co-presence of A. ferrooxidans and pyrite containing mine tailings, $Fe^{2+}$ oxidation and hence electron production increases, which, in turn, improves current density. This study can be applied to utilize ecological functions of indigenous bacteria in mine areas to enhance electricity generation efficiency.

• Korean Journal of Ecology and Environment
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• v.44 no.1
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• pp.85-94
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• 2011

Present study aimed to investigate the effect of zinc accumulation on the tissues of Carassius auratus with various rearing condition. Heavy metal, Zn, was accumulated in the gill, bone and muscle increased for exposure period of 40 days. Moreover, the accumulated concentration of Zn in the gill showed relatively higher than that in other tissues. Also, activities of antioxidant enzymes in the gill, kidney, liver and muscle tissues after exposure to Zn were increased in the manner of exposure period. Antioxidant enzyme activities were shown higher in the gill and muscle than those in the kidney and liver tissues. The gill of C. auratus showed abnormal shapes in its secondary lamellae by long time exposure condition and determined the increased numbers of mucous cells in gill exposed to Zn. In addition, the edema, the exfoliation of epithelial cell was shown in the gill and membrane damages were observed in mitochondria and nucleus. In the kidney, we observed not only the atrophied glomerulus, but the expansion of empty space in Bowman's capsule. Based on the above results, it is considered that the exposure to the high level of Zn for long period possibly involves in the decrease of respiratory and excretory rates, giving rise to secondary lesion of tissues.