• Journal of Korean Society of Environmental Engineers
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• v.28 no.3
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• pp.308-315
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• 2006

Since sewage characteristics are the most important factors that can affect the biological reactions in wastewater treatment plants, a detailed understanding on the characteristics and on-line measurement techniques of the influent sewage would play an important role in determining the appropriate control strategies. In this study, samples were taken at two hour intervals during 51 days from $1^{st}$ October to $21^{st}$ November 2005 from the influent gate of sewage treatment plant. Then the characteristics of sewage were investigated. It was found that the daily values of flow rate and concentrations of sewage components showed a defined profile. The highest and lowest peak values were observed during $11:00{\sim}13:00$ hours and $05:00{\sim}07:00$ hours, respectively. Also, it was shown that the concentrations of sewage components were strongly correlated with the absorbance measured at 300 nm of UV. Therefore, the objective of the paper is to develop on-line estimation technique of the concentration of each component in the sewage using accumulated profiles of sewage, absorbance, and flow rate which can be measured in real time. As a first step, regression analysis was performed using the absorbance and component concentration data. Then a neural network trained with the input of influent flow rate, absorbance, and inflow duration was used. Both methods showed remarkable accuracy in predicting the resulting concentrations of the individual components of the sewage. In case of using the neural network, the predicted value md of the measurement were 19.3 and 14.4 for TSS, 26.7 and 25.1 for TCOD, 5.4 and 4.1 for TN, and for TP, 0.45 to 0.39, respectively.

• Korean Journal of Environment and Ecology
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• v.29 no.6
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• pp.895-906
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• 2015

This study was carried out to the structure of plant community from Sinseongam to Jungdaesa in Odaesan National Park, furthermore, it seeks to curate the basic data for planning of the Abies holophylla's forest management in Odaesan National Park. In order to identify the current ecological environment, this study explored the actual vegetation as primary research and set to twenty plots(i.e. $400m^2$) for analysing detailed structure of plant communities. The research methodology was qualitative analysis, therefore it used TWINSPAN and DCA analysis tools. Especially, TWINSPAN performed well in several comparisons of classification techniques, DCA is one of the ordination technique showed that the plant communities. The plant community was analysed classification and ordination by TWINSPAN and DCA, moreover it was analysed the structure of plant community such as importance percentage of woody species, DBH class distribution, the index of diversity and rate of sample tree growth. The main vegetation was A. holophylla-Quercus mongolica forest and Deciduous broad-leaved forest in the communities where located in low altitude and valley, whereas main vegetation where located in high altitude and slope was Q. mongolica forest. The research site's plant communities were classified four groups. In all of communities, A. holophylla was dominant species in main canopy layer, furthermore, the three communities (community I, II, III) are growing up next generation of A. holophylla excluding community IV. The communities (community I, II, III) can be sustained current status which dominates the A. holophylla communities, simultaneously, there might be expanded the Deciduous broad-leaved communities by Carpinus cordata, Betula schmidtii and so on. While, it showed that the community IV tended to be weaken the forces of A. holophylla, therefore the community IV can be transferred to C. cordata-Deciduous broad-leaved communities in the future. The age of sample trees was 79~128(i.e. A. holophylla), 75~87(i.e. Pinus koraiensis) and 190 years(i.e. Ulmus davidiana var. japonica). The index of Shannon's Species diversity (H') were ranged from 0.3889 to 1.3332 in the communities.

• Journal of Intelligence and Information Systems
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• v.22 no.4
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• pp.177-192
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• 2016

Machine learning is a field of artificial intelligence. It refers to an area of computer science related to providing machines the ability to perform their own data analysis, decision making and forecasting. For example, one of the representative machine learning models is artificial neural network, which is a statistical learning algorithm inspired by the neural network structure of biology. In addition, there are other machine learning models such as decision tree model, naive bayes model and SVM(support vector machine) model. Among the machine learning models, we use SVM model in this study because it is mainly used for classification and regression analysis that fits well to our study. The core principle of SVM is to find a reasonable hyperplane that distinguishes different group in the data space. Given information about the data in any two groups, the SVM model judges to which group the new data belongs based on the hyperplane obtained from the given data set. Thus, the more the amount of meaningful data, the better the machine learning ability. In recent years, many financial experts have focused on machine learning, seeing the possibility of combining with machine learning and the financial field where vast amounts of financial data exist. Machine learning techniques have been proved to be powerful in describing the non-stationary and chaotic stock price dynamics. A lot of researches have been successfully conducted on forecasting of stock prices using machine learning algorithms. Recently, financial companies have begun to provide Robo-Advisor service, a compound word of Robot and Advisor, which can perform various financial tasks through advanced algorithms using rapidly changing huge amount of data. Robo-Adviser's main task is to advise the investors about the investor's personal investment propensity and to provide the service to manage the portfolio automatically. In this study, we propose a method of forecasting the Korean volatility index, VKOSPI, using the SVM model, which is one of the machine learning methods, and applying it to real option trading to increase the trading performance. VKOSPI is a measure of the future volatility of the KOSPI 200 index based on KOSPI 200 index option prices. VKOSPI is similar to the VIX index, which is based on S&P 500 option price in the United States. The Korea Exchange(KRX) calculates and announce the real-time VKOSPI index. VKOSPI is the same as the usual volatility and affects the option prices. The direction of VKOSPI and option prices show positive relation regardless of the option type (call and put options with various striking prices). If the volatility increases, all of the call and put option premium increases because the probability of the option's exercise possibility increases. The investor can know the rising value of the option price with respect to the volatility rising value in real time through Vega, a Black-Scholes's measurement index of an option's sensitivity to changes in the volatility. Therefore, accurate forecasting of VKOSPI movements is one of the important factors that can generate profit in option trading. In this study, we verified through real option data that the accurate forecast of VKOSPI is able to make a big profit in real option trading. To the best of our knowledge, there have been no studies on the idea of predicting the direction of VKOSPI based on machine learning and introducing the idea of applying it to actual option trading. In this study predicted daily VKOSPI changes through SVM model and then made intraday option strangle position, which gives profit as option prices reduce, only when VKOSPI is expected to decline during daytime. We analyzed the results and tested whether it is applicable to real option trading based on SVM's prediction. The results showed the prediction accuracy of VKOSPI was 57.83% on average, and the number of position entry times was 43.2 times, which is less than half of the benchmark (100 times). A small number of trading is an indicator of trading efficiency. In addition, the experiment proved that the trading performance was significantly higher than the benchmark.

• Korean journal of applied entomology
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• v.44 no.2
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• pp.97-108
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• 2005

Samples of water, soil, and sediment were taken from 10 streams near Andong, Korea in May 2004. To assess the degree of environmental pollution of each stream, chemical pollutants such as total notrogen (T-N), total phosphorus (T-P), chemical oxygen demand (COD), heavy metals, organophosphorus pesticides, organochlorine pesticides, and dioxin-like PCB congeners were analyzed by standard process tests or U.S. EPA methods. In addition, biomarkers originated from insect immune systems of beet armyworm, Spodoptera exigua, were used to analysis of the environmental samples. Except Waya-chun stream showing T-N content of 9.12 mg/L, most streams were contaminated with relatively low levels of overall pollutants in terms of T-N, T-P, and COD, compared to their acceptable environmental levels designated by the Ministry of Environment. Contents of Pb and Cd in samples of each stream were much lower than environmentally permissible levels. However, several times higherconcentrations of Pb and Cd were found in locations at Mi-chun, Kilan-chun, and Hyunha-chun streams, in comparison with other streams. Diazinon, parathion, and phenthoate compounds among organophosphorus pesticides were detected as concentrations of 0.19, 0.40, and $1.13\;{\mu}g/g$, respectively, from soil sample collected in the vicinity of Mi-chun stream. On the other hand, 16 organochlorine pesticides and 12 dioxin-like PCB congeners, known as endocrine disrupting chemicals, selected in this study were not found above the limit of detection. Biomarker analyses using insect immune responses indicated that Waya-chun stream was suspected as exposure to environmental pollutants. Limitation and compensation of both environmental analysis techniques are discussed.

• The Journal of the Petrological Society of Korea
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• v.20 no.3
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• pp.161-172
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• 2011

Open beaker digestion method is routinely used as the sample preparation technique for trace element determination of rock samples by inductively coupled plasma mass spectrometry, With this method, however, dissolution of Zr and Hf is not always guaranteed especially when the samples contain refractory minerals. In this study, glass bead digestion technique was compared with conventional open beaker digestion technique for the sample preparation of three USGS rock standards such as AGV-2, BHVO-2, and G-3. Thirty trace elements including rare earth elements were analysed by ICP-MS and ICP-AES. There were no clear differences in analytical results for the AGV-2 and BHVO-2 standards between the two techniques, but Zr, Hf, Y, and middle- to heavy- rare earth element concentrations of the G-3 standard prepared by open beaker digestion technique were significantly lower than the recommended values. This can be attributed to the presence of refractory mineral zircon. On the contrary, all the analytical results of the G-3 standard prepared by glass bead digestion technique were in good agreement with the recommended values, indicating complete dissolution of zircon. The analytical results show that the volatile elements such as Pb and Zn were not lost during the preparation of glass bead. Low dilution glass bead digestion technique described here will be very helpful to enhance precision and accuracy of trace element analysis for geological samples containing refractory minerals.

• Economic and Environmental Geology
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• v.46 no.1
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• pp.51-61
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• 2013

Researches on the oil recovery enhancement using the nanotechnology has recently been studied in the United States. The previous researches has focused mainly on the flow characteristics of nanoparticles in porous media, and the stability of the nano-emulsion itself. However, the analysis did not deal with the size effects between a nano-emulsion and the pore size which has an important role when nano-emulsion flows in the porous media. In this research, nano-based emulsion was fabricated which is able to be applied for the enhanced oil recovery techniques and its characteristics was analyzed. In addition, in order to identify the characteristics of nano-emulsions flowing through the porous media, the size effect was analysed by filtering test. According to the results, when the emulsion was fabricated, SCA(Silane Coupling Agent) or PVA(Poly Vinyl Alcohol) are added to improve the stability of emulsion. As the ratio of the decane to water increased, the viscosity of emulsion and the droplet size also increased. For the filtering test at the atmospheric conditions, the droplet did not go through the filter; only the separated water from the emulsion was able to be filtered. This phenomenon occurred because the droplet was not able to overcome the capillary pressure. At the filtering test by suction pressure, most of the emulsion was filtered over the filter size of $60{\mu}m$. However, the ratio of filtration was rapidly degraded at less than $45{\mu}m$ filters. This is caused due to deformation and destruction of the droplet by strong shear stress when passing through the pore. The results from the study on the basic characteristic of nano-emulsion and filtering test will be expected to play as the important role for the fabrication of the stable nano-emulsion or the research on the recovery of residual oil in porous media.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.2
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• pp.105-113
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• 2015

The theory of landscape architecture applies environmental ethics in order to secure an ecological status. However, environmental ethics that focus on nature conservation excludes landscape architecture as artifacts. In the process, it is hard to identify what landscape architecture insists on as the middle position between humans and nature. Rather, landscape architecture pretends to be an 'agent of nature' and pushes the traditional moral values 'for people.' Therefore, the purpose of this study is to reestablish the anthropocentrism moral position of landscape architecture through critical analysis. Hargrove's weak anthropocentrism' of several environmental ethics branches accepts natural aesthetics(such as landscape architecture) as an ethical virtue. But environmental ethics makes landscape architecture a critical target. For that reason, this study looked into critical contents and objects that in a position to moral, aesthetic and landscape architecture. Critical details are as follows: First, nature is an absolute as an aesthetic and moral value, but landscape architecture is an imitation and takes a relaxed attitude about nature. Second, nature is full of aesthetic substance because it is self-creative, but landscape architecture is designed nature covered human flaws through imagination. Third, environmental management granting techniques in nature generate a moral nihilism. As an argument, environmental ethics overlooked the moral practices of landscape architecture beyond nature another moral aspect of creation and the imagination-and moral aspects of environmental management as 'care' because they rule out 'moral autonomy' and simplify what is considered 'good.' As a result, conservation cannot be the only virtue why the problem of nature in reality cannot be separated from human life. The moral position of landscape architecture based on a 'good life' is more appropriate under anthropocentrism than as a middle position.

• Anatomy & Biological Anthropology
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• v.29 no.4
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• pp.145-154
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• 2016

The purpose of this study was to provide basic biometric data on Korean adults through magnetic resonance imaging (MRI)-based measurements of the distances between the apex of sacral hiatus (SH) and the termination of dural sac (DS), and between SH and conus medullaris (CM) because they are critical to the performance of epidural neuroplasty. A total of 200 patients(88 males and 112 females) with back pain, who had no spine fracture, significant spinal deformity, and spondyloisthesis were selected for this study. The subjects were of mean age 54.3 (20~84) years and mean height 161.3 cm (135~187). T2-weighted MRI images were used for correlation analysis to evaluate the relationships between the distances, and variables such as sex and height. In all patients, the mean distance between SH and DS was $62.8{\pm}9.4mm$ and the mean distance between SH and CM was $232.2{\pm}21.8mm$. The minimum distance and the maximum distance between SH and DS were 34.8 mm and 93.9 mm respectively, and the minimum distance and the maximum distance between SH and CM were 155.0 mm and 284.0 mm respectively. In female patients, both the distances between the SH and DS, and between SH and CM were shorter when compared to those of the male patients(p<0.05). Both the distances between SH and DS and between SH and CM showed a significant correlation with height(p<0.01). The results of this study will provide a useful biometric data on the distances between SH and DS and between SH and CM in Korean in ensuring clinical safety and in the development of more effective catheterization techniques for epidural neuroplasty in Korean.

• Korean Journal of Remote Sensing
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• v.37 no.6_1
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• pp.1611-1623
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• 2021

Thisstudy demonstratessoil moisture and evapotranspiration performance using Korea Land Data Assimilation System (KLDAS) under Korea Land Information System (KLIS). Spin-up was repeated 8 times in 2018. In addition, low-resolution and high-resolution meteorological data were generated using meteorological data observed by Korea Meteorological Administration (KMA), Rural Development Administration (RDA), Korea Rural Community Corporation (KRC), Korea Hydro & Nuclear Power Co.,Ltd. (KHNP), Korea Water Resources Corporation (K-water), and Ministry of Environment (ME), and applied to KLDAS. And, to confirm the degree of accuracy improvement of Korea Low spatial resolution (hereafter, K-Low; 0.125°) and Korea High spatial resolution (hereafter, K-High; 0.01°), soil moisture and evapotranspiration to which Modern-Era Retrospective analysis for Research and Applications, version 2 (MERRA-2) and ASOS-Spatial (ASOS-S) used in the previous study were applied were evaluated together. As a result, optimization of the initial boundary condition requires 2 time (58 point), 3 time (6 point), and 6 time (3 point) spin-up for soil moisture. In the case of evapotranspiration, 1 time (58 point) and 2 time (58 point) spin-ups are required. In the case of soil moisture to which MERRA-2, ASOS-S, K-Low, and K-High were applied, the mean of R² were 0.615, 0.601, 0.594, and 0.664, respectively, and in the case of evapotranspiration, the mean of R² were 0.531, 0.495, 0.656, and 0.677, respectively, indicating the accuracy of K-High was rated as the highest. The accuracy of KLDAS can be improved by securing a large number of ground observation data through the results of this study and generating high-resolution grid-type meteorological data. However, if the meteorological condition at each point is not sufficiently taken into account when converting the point data into a grid, the accuracy is rather lowered. For a further study, it is expected that higher quality data can be produced by generating and applying grid-type meteorological data using the parameter setting of IDW or other interpolation techniques.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.31 no.3
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• pp.129-145
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• 2019

For the design of composite breakwater as representative one of the coastal and harbor structures, it has been widely discussed by the researchers about the relation between the behavior of excess-pore-water pressure inside the rubble mound and seabed caused by the wave load and its structural failure. Recently, the researchers have tried to verify its relation through the numerical simulation technique. The above researches through numerical simulation have been mostly applied by the linear and nonlinear analytic methods, but there have been no researches through the numerical simulation by the strongly nonlinear mutiphase flow analytical method considering wave-breaking phenomena by VOF method and turbulence model by LES method yet. In the preceding research of this study, olaFlow model based on the mutiphase flow analytical method was applied to the nonlinear interaction analysis of regular wave-composite breakwater-seabed. Also, the same numerical techniques as preceding research are utilized for the analysis of irregular wave-composite breakwater-seabed in this study. Through this paper, it is investigated about the horizontal wave pressures, the time variations of excess-pore-water pressure and their frequency spectra, mean flow velocities, mean vorticities, mean turbulent kinetic energies and etc. around the caisson, rubble mound of the composite breakwater and seabed according to the changes of significant wave height and period. From these results, it was found that maximum nondimensional excess-pore water pressure, mean turbulent kinetic energy and mean vorticity come to be large equally on the horizontal plane in front of rubble mound, circulation of inflow around still water level and outflow around seabed is formed in front of rubble caisson.