• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.521-526
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• 2016

Sediment dredging can permanently remove pollutants from an aquatic ecosystem, which is considered an effective approach to aquatic ecosystem restoration. In this study, we quantified the effects of sediment dredging on water quality in Masan Bay by calculation of oxygen demanding rate. We applied ecosystem model including water and sediment quality module in Masan Bay. The results showed that the increase of calculated oxygen demanding rate is significant due to sediment dredging of both inner part and outer part of Masan Bay. On the other hand, the increase is gradual due to decrease of anthropogenic load. It meant sediment dredging can improve water quality of Masan Bay more. Using correlation equation between oxygen demanding rate and sediment oxygen demand, we calculated that the area of sediment dredging which is equal to the effects of 10 % reduction of anthropogenic load. It is $1.68km^2$ in inner part and $3.15km^2$ in outer part of the Masan Bay. This Meant that to improve water quality of Masan Bay, sediment dredging in inner part is efficient method.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.6
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• pp.504-511
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• 1990

Weather data acquisition and potential evapotranspiration (PET) calculation procedure were investigated to support the agricultural development efforts in the mid-altitude mountainous region of Cheju Island. Automated weather stations (AWS) were installed at two points representing the east and the west of the study area. A personal computer was employed to collect the near-real time weather data from AWS through the public telephone line. Hourly data were available for solar radiation, air and soil temperature, relative humidity, wind speed and direction, and precipitation. Based on the data for the month of June 1989, daily climatic features were comparatively analyzed for the two areas and the Penman equation was used to calculate PET. Air temperature was higher by 1 to 2 degree C in the east due mainly to the higher solar radiation and partly to the Fohn effect caused by the daytime southwesterly blowing over Mt. Halla. Diurnal march of soil temperature lagged by 4 hours behind that of air temperature and the diurnal range for 10cm subsurface soil was 3 degree C. Wind was consistently stronger and a marked sea-land breeze circulation was detected in the west. Calculated PET values were higher in the east by 6% than in the west. Overall values from the east and the west of the mid-altitude mountainous region were higher by 30% than those of the coastal region, which were estimated from the Class A Pan evaporation measured by the Korea Meteorological Service Offices.

• Journal of the Korean Geographical Society
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• v.48 no.6
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• pp.897-913
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• 2013

The main purpose of the paper is to examine the spatial characteristics of school choice through residential mobility by conducting a correlation analysis on the relationships between the middle schools' entrance rates to special high schools and the elementary schools' net transfer rates. Analyses are done at both the individual school level and the school catchment area level. Prior to the calculation, the two variables involved in the correlation analysis are transformed via a standardization equation, and the standardized scores are mapped and explored. Both the global and local correlation analyses are done for the standardized variables. Main findings are twofold. First, the global correlation analysis reports that there exists a statistically significant correlation between the two variables at both the analytical levels. Second, albeit the prominent positive correlation at the global level, the local analysis reveals the existence of a considerable level of spatial heterogeneity in terms of bivariate association. While several school catchment areas with very high local correlation coefficients (the HH association type) are popped up, other areas with various types of bivariate association including ones even opposite to the global trend are also observed.

• Journal of the Korean GEO-environmental Society
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• v.21 no.1
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• pp.5-12
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• 2020

Vibration propagated from seismic sources has damping according to distance and amplification and reduction characteristic in different regions according to topography and geological structure. The vibration propagated from the seismic source to the bedrock is largely affected by the damping according to the separation distance, which can be simply estimated through the damping equation. However, it is important to grasp geological information by location because vibration estimation transmitted to the surface are affected by the natural period of the soil located above the bedrock. Geotechnical investigation data are needed to estimate the seismic intensity based on geological information. If there is no Vs profile, the standard penetration tests are mainly used to determine the soil parameters. The Integrated DB Center of National Geotechnical Information manages the geotechnical survey data performed on the domestic ground, and there is the standard penetration test information of 400,000 holes. In this study, the possibility of quantitation the amplification coefficient for each region was examined to calculated the physical interactive seismic intensity based on geotechnical information. At this time, the shear wave column diagram was generated from the SPT-N value and ground response analysis was performed in the target area. The site coefficients for each zone and the seismic intensity distribution for the seismic motion present a significant difference according to the analysis method and the regional setting.

• Korean Journal of Ecology and Environment
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• v.47 no.4
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• pp.350-357
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• 2014

Harmful Algal Bloom Alert System (HABAS) for drinking water supply is require to fast and accurate count as system monitoring of cyanobacterium occurrence and inducing a response action. We measured correlation between colony size and cell number including genus Anabaena, Aphanizomenon, Microcystis, Oscillatoria which are targeted at HABAS, deducted from standard formula, and suggested calculation method from colony size to the number of cell. We collected cyanobacteria samples at Han River (Paldang reservoir), Nakdong River (Dalseong weir, Changnyeonghaman weir) and Geum River (Gobok reservoir) from August to October, 2013. Also, we studied correlation between colony size and cell number, and calculated regression equation. As a result of correlation of harmful cyanobacteria by genus, Anabaena spp. and Aphanizomenon spp. having trichome showed high correlation coefficients more than 0.93 and Microcystis spp. having colony showed correlation coefficient of 0.76. As a result of correlation of harmful cyanobacteria by species, Anabaena crassa, Aphanizomenon flos-aquae, A. issatschenkoi, Oscillatoria curviceps, O. mougeotii having trichome showed high correlation coefficients from 0.89 to 0.96, and Microcystis aeruginosa, M. wessenbergii, M. viridis having colony showed correlation coefficients from 0.76 to 0.88. Compared with other genus Microcystis relatively showed low correlation because even species and colony size are the same, cell density and cell size are different from Microcystis strains. In this study, using calculated regression might be fast and simple method of cell counting. From now on, we need to secure additional samples, and make a decision to study about other species.

• Journal of Korea Water Resources Association
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• v.39 no.4 s.165
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• pp.299-311
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• 2006

In this paper it is outlined the methodology of estimating the parameters of water balance analysis method for calculating recharge, using ground water level rises in monitoring well when values of specific yield of aquifer are not available. This methodology is applied for two monitoring wells of the case study area in northern area of the Jeiu Island. A water balance of soil layer of plant rooting zone is computed on a daily basis in the following manner. Diect runoff is estimated by using SCS method. Potential evapotranspiration calculated with Penman-Monteith equation is multiplied by crop coefficients($K_c$) and water stress coefficient to compute actual evapotranspiration(AET). Daily runoff and AET is subtracted from the rainfall plus the soil water storage of the previous day. Soil water remaining above soil water retention capacity(SWRC) is assumed to be recharge. Parameters such as the SCS curve number, SWRC and Kc are estimated from a linear relationship between water level rise and recharge for rainfall events. The upper threshold value of specific yield($n_m$) at the monitoring well location is derived from the relationship between rainfall and the resulting water level rise. The specific yield($n_c$) and the coefficient of determination ($R^2$) are calculated from a linear relationship between observed water level rise and calculated recharge for the different simulations. A set of parameter values with maximum value of $R^2$ is selected among parameter values with calculated specific yield($n_c$) less than the upper threshold value of specific yield($n_m$). Results applied for two monitoring wells show that the 81% of variance of the observed water level rises are explained by calculated recharge with the estimated parameters. It is shown that the data of groundwater level is useful in estimating the parameter of water balance analysis method for calculating recharge.

• Archives of design research
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• v.17 no.1
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• pp.211-220
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• 2004

The Chaos theory of complexity and Fractal theory which became a prominent figure as a new paradigm of natural science should be understood not as whole, and not into separate elements of nature. Fractal Dimensions are used to measure the complexity of objects. We now have ways of measuring things that were traditionally meaningless or impossible to measure. They are capable of describing many irregularly shaped objects including man and nature. It is compatible method of application to express complexity of nature in the dimension of non-fixed number by placing our point of view to lean toward non-linear, diverse, endless time, and complexity when we look at our world. Fractal Dimension allows us to measure the complexity of an object. Having a wide application of fractal geometry and Chaos theory to the art field is the territory of imagination where art and science encounter each other and yet there has not been much research in this area. The formative word has been extracted in this study by analyzing objective data to grasp formative principle and geometric characteristic of (this)distinct figures of Fractals. With this form of research, it is not so much about fractal in mathematics, but the concept of self-similarity and recursiveness, randomness, devices expressed from unspeakable space, and the formative similarity to graphic design are focused in this study. The fractal figures have characteristics in which the structure doesn't change the nature of things of the figure even in the process if repeated infinitely many times, the limit of the process produces is fractal. Almost all fractals are at least partially self-similar. This means that a part of the fractal is identical to the entire fractal itself even if there is an enlargement to infinitesimal. This means any part has all the information to recompose as whole. Based on this scene, the research is intended to examine possibility of analysis of fractals in geometric characteristics in plasticity toward forms in graphic design. As a result, a beautiful proportion appears in graphic design with calculation of mathematic. It should be an appropriate equation to express nature since the fractal dimension allows us to measure the complexity of an object and the Fractla geometry should pick out high addition in value of peculiarity and characteristics in the complex of art and science. At the stage where the necessity of accepting this demand and adapting ourselves to the change is gathering strength is very significant in this research.

• Journal of the Korean Society of Groundwater Environment
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• v.7 no.3
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• pp.103-115
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• 2000

The formation of brown-colored precipitates is one of the serious problems frequently encountered in the development and supply of groundwater in Korea, because by it the water exceeds the drinking water standard in terms of color. taste. turbidity and dissolved iron concentration and of often results in scaling problem within the water supplying system. In groundwaters from the Pajoo area, brown precipitates are typically formed in a few hours after pumping-out. In this paper we examine the process of the brown precipitates' formation using the equilibrium thermodynamic and kinetic approaches, in order to understand the origin and geochemical pathway of the generation of turbidity in groundwater. The results of this study are used to suggest not only the proper pumping technique to minimize the formation of precipitates but also the optimal design of water treatment methods to improve the water quality. The bed-rock groundwater in the Pajoo area belongs to the Ca-$HCO_3$type that was evolved through water/rock (gneiss) interaction. Based on SEM-EDS and XRD analyses, the precipitates are identified as an amorphous, Fe-bearing oxides or hydroxides. By the use of multi-step filtration with pore sizes of 6, 4, 1, 0.45 and 0.2 $\mu\textrm{m}$, the precipitates mostly fall in the colloidal size (1 to 0.45 $\mu\textrm{m}$) but are concentrated (about 81%) in the range of 1 to 6 $\mu\textrm{m}$in teams of mass (weight) distribution. Large amounts of dissolved iron were possibly originated from dissolution of clinochlore in cataclasite which contains high amounts of Fe (up to 3 wt.%). The calculation of saturation index (using a computer code PHREEQC), as well as the examination of pH-Eh stability relations, also indicate that the final precipitates are Fe-oxy-hydroxide that is formed by the change of water chemistry (mainly, oxidation) due to the exposure to oxygen during the pumping-out of Fe(II)-bearing, reduced groundwater. After pumping-out, the groundwater shows the progressive decreases of pH, DO and alkalinity with elapsed time. However, turbidity increases and then decreases with time. The decrease of dissolved Fe concentration as a function of elapsed time after pumping-out is expressed as a regression equation Fe(II)=10.l exp(-0.0009t). The oxidation reaction due to the influx of free oxygen during the pumping and storage of groundwater results in the formation of brown precipitates, which is dependent on time, $Po_2$and pH. In order to obtain drinkable water quality, therefore, the precipitates should be removed by filtering after the stepwise storage and aeration in tanks with sufficient volume for sufficient time. Particle size distribution data also suggest that step-wise filtration would be cost-effective. To minimize the scaling within wells, the continued (if possible) pumping within the optimum pumping rate is recommended because this technique will be most effective for minimizing the mixing between deep Fe(II)-rich water and shallow $O_2$-rich water. The simultaneous pumping of shallow $O_2$-rich water in different wells is also recommended.