• The Journal of the Korea Contents Association
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• v.13 no.12
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• pp.19-26
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• 2013

In this paper, we present a novel illumination system for parking lots constructed underground. We design and implement this system using microwave sensors and dimming control of LED fluorescent lamps so that we can obtain lighting efficiency of the illumination scheme. We construct an effective illumination system in the aspects of performance and cost, resulting in energy-saving and electricity reduction. Recently conventional energy-saving method applied to old underground parking lots mainly relies upon turning off the half of total number of lamps installed in the parking lot. Sometimes there are some lots that have infrared sensor to be used to turn on/off the fluorescent lamps to realize these operations smoothing. The other schemes utilize timer to control lighting time of the fluorescent lamps. These conventional schemes are forcing to turn off a part of lamps installed so that we cannot apply them in a systematic way. Moreover they will be most inefficient when we leave them alone to be continuous consumers. The lighting control system proposed in this paper can recognize objects through microwave sensors and inform the appropriate lighting time, furthermore we can adjust brightness of LED lamps following the surroundings using dimming control scheme so that we can epochally improve the illumination system for underground parking lots. According to our sophisticated test experiments, we can maximally obtain 81.9% of energy-saving effectiveness using the system proposed in this paper.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.11
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• pp.1985-1994
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• 2000

This research was designed to investigate the effect of initial adsorbed amount of phenol, temperature, and pH on the desorption reaction of phenol from spent activated carbon loaded with phenol. Methanol, acetone, and N,N-dimethylformamide( DMF) were used as test organic solvents. The initial adsorbed quantities of phenol investigated here were 166.1mg/g, 180.7mg/g, and 197.9mg/g. The effect of temperature was evaluated from 15 to $55^{\circ}C$ with an interval of $10^{\circ}C$, while that of pH was investigated under acidic. neutral. and alkaline conditions. The extent of phenol desorption was proportional to the strength of dipole moment such as methanol < acetone < DMF. Over 90% desorption of phenol was achieved by acetone and DMF. The quantity of des orbed phenol by the organic solvents decreases with increasing the initial adsorbed amount of phenol. DMF is affected least by the initially adsorbed amount of phenol. An increase in reaction temperature leads to higher desorption of phenol. Desorption reaction by methanol is most sensitive to the temperature. As the pH of solvents increases. the desorption rate is also increasing. At pH=12. the desorption rate of phenol by methanol increases sharply by 10%. Although methanol demonstrated the weakest desorption power. the desorption capacity of methanol would approach that of acetone and DMF by adjusting temperature and pH. Methanol may emerge as a promising solvent for removing phenol from activated carbon because of acceptable regeneration efficiency as well as relatively cheap price.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1095-1104
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• 2009

The objective of this research was to evaluate the feasibility of using oyster-shell and eggshell wastes for the stabilization of arsenic-contaminated soil. Artificial As(V) contaminated soil was mixed with 0~5% oyster-shell and eggshell wastes and each sample was incubated for 30 days in a controlled environment. The efficiency of each treatment was evaluated using various single extractants (1 N HCl, 0.1 N NaOH and 0.5 N $H_2SO_4$). The concentration of As(V) was reduced by 10% upon a 5% oyster-shell or eggshell waste treatments based on the Korea Standard Test method (1 N HCl extraction). Analogous trends were observed in the 0.1 N NaOH or 0.5 N $H_2SO_4$ extractions. In addition, the oyster-shell and eggshell waste treatments increased the pH of each soil from 6.54 (Control) to 7.62~7.94. The exchangeable Ca in each soil also sharply increased from 6.87 cmol(+)/kg (Control) to 12.77~20.18 cmol(+)/kg. Further research is needed to increase the effectiveness of the oyster-shell and eggshell waste for the stabilization of As(V) in the contaminated soil.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.4
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• pp.423-429
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• 2008

Application of manganese-impregnated activated carbon(Mn-AC) in the treatment of synthetic wastewater containing both organic and inorganic contaminants was investigated. Phenol and As(III) was used as representative organic and inorganic contaminants, respectively. When the stability of Mn-AC at acidic condition was evaluated with variation of solution pH ranging from 2 to 4, Mn-AC was unstable below pH 3, while negligible dissolution of Mn was observed above pH 4. This stability test suggests a plausible applicability of Mn-AC in the treatment of wastewater above pH 4. Compared to AC-alone, the adsorption rates of phenol as well as adsorbed amounts of phenol by Mn-AC were slightly decreased due to the decrease of the surface area by impregnation. The maximum adsorbed amount of phenol by Mn-AC was corresponds to 75% of that by AC-alone from the adsorption isotherm study. The oxidation efficiency of As(III) by Mn-AC was greater than that by AC-alone at lower pHs while reverse trend was observed as pH increased above 7. From this work, it was found that Mn-AC could be used in the simultaneous treatment of both phenol and As(III).

• Journal of Biosystems Engineering
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• v.43 no.2
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• pp.148-159
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• 2018

Purpose: Unmanned air vehicle (UAV) remote sensing was applied to test various vegetation indices and make prediction models of protein content of rice for monitoring grain quality and proper management practice. Methods: Image acquisition was carried out by using NIR (Green, Red, NIR), RGB and RE (Blue, Green, Red-edge) camera mounted on UAV. Sampling was done synchronously at the geo-referenced points and GPS locations were recorded. Paddy samples were air-dried to 15% moisture content, and then dehulled and milled to 92% milling yield and measured the protein content by near-infrared spectroscopy. Results: Artificial neural network showed the better performance with $R^2$ (coefficient of determination) of 0.740, NSE (Nash-Sutcliffe model efficiency coefficient) of 0.733 and RMSE (root mean square error) of 0.187% considering all 54 samples than the models developed by PR (polynomial regression), SLR (simple linear regression), and PLSR (partial least square regression). PLSR calibration models showed almost similar result with PR as 0.663 ($R^2$) and 0.169% (RMSE) for cloud-free samples and 0.491 ($R^2$) and 0.217% (RMSE) for cloud-shadowed samples. However, the validation models performed poorly. This study revealed that there is a highly significant correlation between NDVI (normalized difference vegetation index) and protein content in rice. For the cloud-free samples, the SLR models showed $R^2=0.553$ and RMSE = 0.210%, and for cloud-shadowed samples showed 0.479 as $R^2$ and 0.225% as RMSE respectively. Conclusion: There is a significant correlation between spectral bands and grain protein content. Artificial neural networks have the strong advantages to fit the nonlinear problem when a sigmoid activation function is used in the hidden layer. Quantitatively, the neural network model obtained a higher precision result with a mean absolute relative error (MARE) of 2.18% and root mean square error (RMSE) of 0.187%.

• Journal of Korean Society of Disaster and Security
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• v.6 no.3
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• pp.9-17
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• 2013

Geospatial information data came recently in use to build the location-based service in various fields. These data were shown via a 2-D map in the past but now can be viewed as a 3-D map due to the dramatic evolution of IT technology, thus improving efficiency and raising practicality to a greater extent by providing a more realistic visualization of the field. In addition, many previous GIS applications have been provided under desktop environment, limiting access from remote sites and reducing its approachability for less experienced users. The latest trend offers service with web-based environment, providing efficient sharing of data to all users, both unknown and specific internal users. Therefore, real-time information sensors that have been installed on steep slopes are to be integrated with 3-D geospatial information in this study. It is also to be developed with web-based environment to improve usage and access. There are three steps taken to establish this system: firstly, a 3-D GIS database and 3-D terrain with higher resolution aerial photos and DEM (Digital Elevation Model) have been built; secondly, a system architecture was proposed to integrate real-time sensor information data with 3D Web-based GIS; thirdly, the system has been constructed for Gangwon Province as a test bed to verify the applicability.

• The Journal of Engineering Geology
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• v.20 no.4
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• pp.449-459
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• 2010

We performed numerical simulations of the excavation of an underground structure (the Giheung Tunnel) in order to evaluate the rate of groundwater flow into the structure and to estimate the groundwater level around the structure. The tunnel was constructed in Precambrian bedrock in Gyeonggi Province, South Korea. Geological and electrical resistivity data, as well as hydraulic test data, were used for the numerical modeling. The modeling took into account the strike-slip faults that cross the southern part of Giheung Tunnel, as these structures influence the discharge of groundwater into the tunnel. The transient modeling estimated a groundwater flow rate into the tunnel of $306\;m^3$/day, with a grout efficiency of 40%, yielding good agreement between the calculated change in groundwater level (6.20 m) and that observed (6.30 m) due to tunnel excavation.

• Journal of Environmental Impact Assessment
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• v.25 no.6
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• pp.384-401
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• 2016

The vegetation assessment indicator has been developed recently as a biological part of the integrated assessment system for river environment to improve the efficiency of river restoration projects. This study carried out to test the vegetation assessment indicator and to reset its grade criteria on experimental streams. We classified and mapped vegetation communities at the level of physiognomic-floristic composition by each assessment unit. A total of 204 sampling quadrats were set up on the 68 assessment units at 5 experimental streams. By analyzing the vegetation data collected, we examined the appropriate numbers of sampling quadrats, the criteria of vegetation index score, classification of vegetation community, and grade criteria for vegetation assessment. The developed vegetation assessment indicator composed with the vegetation complexity index (VCI), the vegetation diversity index (VDI), and the vegetation naturalness index (VNI) was proved to reflect the current conditions of the streams sufficiently. The contribution of vegetation naturalness index to grading by vegetation assessment indicator was larger, but three indexes were closely correlated to each other. Also there was more clearer discrimination of grading with the application of adjusted criteria of vegetation assessment indicator and the standardized classification of vegetation community, but the stream segment type did not influence the vegetation assessment grade significantly.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.3
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• pp.171-180
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• 2013

Even though styrofoam buoys represent a large portion of beached marine debris in Korea, efficient government actions have been lacking to address them. Three participatory workshops were organized from 2010 to 2012 to develop policy measures to manage styrofoam buoy marine debris. The first workshop held in 2010 was organized in order for workshop participants to understand and share the styrofoam debris issue. Participating stakeholders suggested policy measures to address styrofoam debris through brainstorming in the second workshop in 2011. In the third workshop organized in 2012, the analytic hierarchy process (AHP) was used to set priorities for 16 selected policy measures. A total of 56 people participated in AHP, and answers of 40 participants that passed the consistency test were analyzed. 'Beach cleanup by public works program' ranked highest in priority, followed by 'Development of alternative buoy and aquaculture technologies'. Other research projects also ranked high in priority. Feasibility of policy measures was considered the most important criterion in the priority setting, followed by effectiveness, efficiency, and acceptability. This study demonstrated that participatory workshops in which diverse stakeholders take part in could provide a valuable tool in developing practical policy measures on styrofoam buoy marine debris.

• Journal of Biomedical Engineering Research
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• v.21 no.6
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• pp.615-621
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• 2000

A social phobia is an anxiety disorder characterized by extreme fear and phobic avoidance of social and performance situations. Medications or cognitive-behavior methods have been mainly used in treating it. These methods have some shortcomings such as being inefficient and difficult to apply to treatment. Lately the virtual rcality technology has been applied to dcal with the anxiety disorders in order to compcnsate for these defects. A virtual environment provides a patient with stimuli which cvokes a phobia. and the patient's exposure to the virtual phobic situation make him be able to overcome it. In this study, we suggested the public speaking simulator based on a personal computer for the treatment of social phobia. The public speaking simulator was composed of a position sensor. head mount display and audio system. And a virtual environment for the treatment was suggested to be a seminar room where 8 avatars are sitting. The virtual environment includes a tracking system the trace a participant's head-movement using a HMD with position sensor and 3D sound is added to the virtual environment so that he might fcel it realistic. We also made avatars' motion and facial expression change in reaction to a participant's speech. The goal of developing public speaking simulator is to apply to treat fear of public speaking efficiently and economically. In a future study. we should get more information about immergence and treatment efficiency by clinical test and apply it to this simulator.