• Environmental Engineering Research
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• v.21 no.3
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• pp.256-264
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• 2016

2-Methylisoborneol (2-MIB) is one of typical odorants in potable water sources, which is hardly removed by conventional water treatment process. In this study, three strains capable of removing 2-MIB singly from drinking water were isolated from activated carbon of sand filter. They were identified to be Shinella zoogloeoides, Bacillus idriensis and Chitinophagaceae bacterium based on 16S rRNA gene sequence analysis. In mineral salts medium without external carbon source, removal efficiencies of $20{\mu}g/L$ 2-MIB in three days were 23.3%, 32.9% and 17.0% for Shinella zoogloeoides, Bacillus idriensis and Chitinophagaceae bacterium, respectively. The biodegradation of 2-MIB was significantly improved with the presence of cometabolism carbon(glycerol, glucose, etc.). In the period of 20 days, Bacillus idriensis can remove 2 mg/L MIB to $368.2{\mu}g/L$ and $315.4{\mu}g/L$ in mineral salts medium without and with glycerol respectively. The removal of 2-MIB by Bacillus idriensis was from 2 mg/L to $958.4{\mu}g/L$ in Xiba river samples on 15 days.

• Tunnel and Underground Space
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• v.17 no.6
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• pp.453-463
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• 2007

Terzaghi's tunnel pressure theory is generally used to estimate primary design pressures on tunnel support for shield and urban NATM tunnels until now. A trial is made in this paper to investigate the interaction between the ground deformation behavior and Terzaghi's tunnel pressure, which assumes pound's limit (or critical) state, by considering results of 'Terzaghi's tunnel pressure theory. two-dimensional reduced-scale model tunnel tests and nonlinear numerical analysis based on strain softening modeling. A full understanding between tunnel pressure and ground deformation behavior under the tunnel excavation and an effective utilization of this interaction lead to an economical tunnel support design and a safe construction of tunnel.

• Proceedings of the KSRS Conference
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• v.1
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• pp.512-515
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• 2006

Forest stand height and volume are important indicators for management purpose as well as for the environmental analysis. Shuttle Radar Topography Mission (SRTM) is backscattered over forest canopy and DSM can be acquired from such scattering characteristic, while National Elevation Dataset (NED) provides bare earth elevation data. The difference between SRTM and NED is estimated as tree height, and it is correlated with forest parameters, it is correlated with forest parameters, including average DBH, Trees per acre, net BF per acre, and total Net MBF. Especially, among them, net Board Foot(BF) per acre is the index that well represents forest volume. The Project site was Douglas-fir dominating plantation area in the western Washington an the northern Oregon in the U.S. This study shows a relationship of high correlation between the forest parameters and the product from SRTM, NED, and ETM+. This research performs multi regression analysis and regression tree algorithm, and can get more improved relationship between several parameters.

• Proceedings of the KSRS Conference
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• v.1
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• pp.260-262
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• 2006

One of future remote sensing techniques for transportation application is vehicle detection from the space, which could be the basis of measuring traffic volume and recognizing traffic condition in the future. This paper introduces an approach to vehicle detection using image object segmentation approach. The object-oriented image processing is particularly beneficial to high-resolution image classification of urban area, which suffers from noisy components in general. The project site was Dae-Jeon metropolitan area and a set of true color aerial images at 10cm resolution was used for the test. Authors investigated a variety of parameters such as scale, color, and shape and produced a customized solution for vehicle detection, which is based on a knowledge-based hierarchical model in the environment of eCognition. The highest tumbling block of the vehicle detection in the given data sets was to discriminate vehicles in dark color from new black asphalt pavement. Except for the cases, the overall accuracy was over 90%.

• Water Engineering Research
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• v.5 no.3
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• pp.111-121
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• 2004

For the long-term strategic water resources planning, forecasting the future streamflow change is important to meet the demand of a growing society. The streamflow variation to the decade-long precipitation was investigated for the two major stage gauging stations in Korea. Precipitation and runoff characteristics have been analyzed at Yongwol stream stage in the Han River as well as Sutong stream stage in the Kum River for the future water resources management strategies. Monte Carlo method has been applied to estimate the future precipitation and runoff. Based on the trend line of 10-year moving average of runoff depth for the historical runoff records, the relation between runoff and the time variation was examined in more detail using regression analysis. This study showed that the surface flows have been significantly decreased while precipitation has been stable in these basins. Decreasing in runoff reflects the regional watershed characteristics such as forest cover changes. The findings of this study could contribute to the planning and development for the efficient water resources utilization.

• Journal of Environmental Science International
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• v.15 no.4
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• pp.359-364
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• 2006

Two sites with different average daily traffic volume at an intersection were selected in order to investigate water quality of the first flushes in the surface runoffs. The effects of rainfall intensities and accumulated non-rainy days before rainfall events on the water quality were also delineated. Samples were collected at every 2 min. interval from each first flush from February to May, 2004 for 4 major rainfall events. $COD_{cr}$ or SS concentrations at the site with an average daily traffic volume (ADTV) of 23,000 vehicles were 2-7 times higher than those at the site with an ADTV of 1,400 vehicles. The longer the accumulated non-rainy days were, the higher the concentration of heavy metals were than those of $COD_{cr}$ and SS in the first flushes.

• Journal of Environmental Science International
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• v.18 no.2
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• pp.239-244
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• 2009

In this study, to stabilize the heavy metal in the contaminated soils, the column leaching test based on rainfall and pH value was performed by using coal mine drainage sludge(CMDS): which was generated during electrical purification of abandoned coal mine wastewater. Four types of testing column were used in this study. That were the CMDS and the heavy metal contaminated soils well mixed in 0 wt%, 1 wt%, 3 wt% and 3 wt% layered column. According to the investigation, when the influent pH was $5.5{\sim}6.2$, there were no heavy metal elution at all conditions, and when the influent pH was $3{\sim}3.3$, the order of Cu, Zn, Pb, Cr elution concentration was 3 wt% M(mixed)<3 wt% S(separation)<1 wt% M<0 wt% and the average elution concentration was quite low, the value was 0.005 mg/L. Therefore, CMDS can used as new stabilizer of the heavy metal in the contaminated soils.

• Journal of Ocean Engineering and Technology
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• v.24 no.4
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• pp.13-22
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• 2010

While a caisson used for breakwater is carried by a floating dock, accompanying stability problem by its existing motions in the dock is quite important and should be pre-checked against sea environmental condition. In the stability analysis, the acceleration, velocity, angle of roll and pitch motions are important to calculate frictional force and separation force. If separation force becomes bigger than frictional force, serious collision may be occurred between caisson and floating dock. In this study, stability evaluation during the transportation of a caisson on floating dock for breakwater was performed by using a commercial program, HydroD and CHARM3D/HARP.

• Journal of Ocean Engineering and Technology
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• v.21 no.6
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• pp.34-41
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• 2007

The present study investigates numerically damping characteristics of irregular waves passing over a permeable seabeds. At first, the numerical model, which is able to consider the flow through a porous medium with inertial, laminar and turbulent resistance terms and determine the eddy viscosity with LES turbulent model, is validated by comparing with existing experimental data. And then, the numerical test on irregular wave damping over a permeable seabeds is performed in case that wave and flume conditions are changed. It is revealed from the numerical results that the more porosity and mean grain are increased, the more wave damping is increased. Also, the effect of wave period on damping of irregular waves over a permeable seabed is discussed.

• Journal of Environmental Science International
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• v.15 no.5
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• pp.431-438
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• 2006

The strength, water permeability, and photo-degradation efficiency of NOx of porous concrete with a new concept were studied in this paper. The porous concrete was comprised of coarse aggregate of maximum size 40 mm, cement, silica fume, water and air-entraining(AE) water reducing agent. The strength of porous concrete was strongly related to its matrix proportion and compaction energy. An experimental test was carried out to study the parameters of cement proportions and silica fume content for pavement applications of porous concrete which were paving a footpath, a bikeway, a parking lot, and a driveway. The regressed equations of relation-ships between compressive strength and flexural strength, and coefficient permeability and void ratios were indicated as y=7.69x+71.74 and $y=0.42e^{0.28x}$. A method of making an air purification-functioning road, which was spraying a mixture of a photocatalyst, cement, and water onto the surface of the road, was suggested.