• Korean Journal of Remote Sensing
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• v.30 no.1
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• pp.47-59
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• 2014

Volcanic ash (VA) can be estimated by remote sensing sensors through their spectral signatures determined by the inherent optical property (IOP) including complex refractive index and the scattering properties. Until now, a very limited range of VA refractive indices has been reported and the VA from each volcanic eruption has a different composition. To improve the robustness of VA remote sensing, there is a need to understanding of VA - radiation interactions. In this study, we calculated extinction coefficient, scattering phase function, asymmetry factor, and single scattering albedo which show different values between andesite and pumice. Then, IOPs were used to analyze the relationship between theoretical remote sensed radiation calculated by radiative transfer model under various aerosol optical thickness (${\tau}$) and sun-sensor geometries and characteristics of VA. It was found that the mean rate of change of radiance at top of atmosphere versus ${\tau}$ is six times larger than in radiance values at 0.55 ${\mu}m$. At the surface, positive correlation dominates when ${\tau}$ <1, but negative correlation dominates when ${\tau}$ >1. However, radiance differences between andesite and pumice at 11 ${\mu}m$ are very small. These differences between two VA types are expressed as the polynomial regression functions and that increase as VA optical thickness increases. Finally, these results would allow VA to be better characterized by remote sensing sensors.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.2
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• pp.151-163
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• 2006

Although various methods for effective modeling of pre-reinforced zones have been suggested for numerical analysis of large section tunnels, tunnel designers refer to empirical cases and literature reviews rather than engineering methods because ones who use commercial programs are unfamiliar with a macro-scale approach in general. Therefore, this paper suggests a simple micro-scale approach combined with the macro-scale approach to determine equivalent design parameters for effective numerical modeling of pre-reinforced zones in tunnel. This new approach is to determine the equivalent stiffness of pre-reinforced zones with combination of ground, bulb, and steel in series or/and parallel. For verification, 3-D numerical results from the suggested approach are compared with those of a realistic model. The comparison suggests that two cases make best approximation to a realistic solution: One is related to the series-parallel stiffness system (hereafter SPSS) in which bulb and steel are coupled in parallel and then connected to the ground in series, and the other is the series stiffness system (hereafter SSS) in which only bulb and steel are coupled in series. The SPSS is recommended for stiffness calculation of pre-reinforced zones because the SSS is inconvenient and time-consuming. The SPSS provides slightly bigger vertical displacement at tunnel crown in weathered rock than other cases and give almost identical results to a realistic model for horizontal displacement at tunnel spring line and ground surface settlement. Displacement trends on weathered rock and weathered soil are similar. The SPSS which is suggested in this paper represents the behavior mechanism of pre-reinforced area effectively.

• Atmosphere
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• v.26 no.3
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• pp.413-421
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• 2016

Climate Analysis Seoul (CAS) which provides gridded data relevant for thermal assessment was applied to one of the urban green areas, the Seonjeongneung, in Seoul, Korea. The thermal environment in the Seonjeongneung was evaluated from the CAS simulation for the five heat-wave issued cases during the last five years (2011~2015). The CAS has been improved continuously since it was developed. An updated version with a higher resolution of the CAS simulation domain and an addition of the vegetation information was used in this study. The influence of vegetation in the Seonjeongneung is estimated through the amount of the cold air generation ($Q_{ca}$) and air temperature deviation at each grid points, which are calculated by incorporating Geographic Information System (GIS) analysis on the simulation domain and meteorological analysis with the METeorology and atmospheric PHOtochemistry mesoscale MODel (MetPhoMod) in the CAS. The average amount of the cold air generation ($Q_{ca}$) at the Seonjeongneung is about $25.5m^3m^{-2}h^{-1}$ for the whole cases, and this value is similar to the ones in a forest or a well-wooded region. The average value of the total air temperature deviation (TD) is $-2.54^{\circ}C$ at the Seonjeongneung for the five cases. However, this cooling effect of the urban green area disappeared when the region is replaced by high-rise buildings in the CAS simulation. The $Q_{ca}$ drastically decreases to about $1.1m^3m^{-2}h^{-1}$ and the average TD shows an increase of $1.14^{\circ}C$ for the same events. This result shows that the vegetation in the Seonjeongneung supposes to keep down temperature during the heat-wave issued day and the average cooling effect of the green region is $3.68^{\circ}C$ quantitatively from the TD difference of the two simulations. The cooling effect represented with the TD difference is larger than $0.3^{\circ}C$ within 200 m distance from the boundary of the Seonjeongneung. Further improvements of the thermodynamical and advection processes above the model surface are required to consider more accurate assessment of the cooling effect for the urban green area.

• The Journal of Engineering Geology
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• v.10 no.1
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• pp.1-12
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• 2000

Heaving of road and subsidence of slope took place at the Wiri region of the local highway 999 in Gyeongsangbukdo, Korea after heavy rain in the next year of construction. Although the state government had performed remedial treatments by reducing the angle and the height of the slope, deformation had never stopped. Therefore, we have preformed the analysis of deformation and stabilityof the slope. Study area consists of the Cretaceous shale, siltstone and sandstone and two faults are found. The major deformation occurred by sliding of rock mass along faults after heavy rain because not only thepore pressure at the fault plane and the unit weight of sliding mass increased, but did the shearstrength of saturated fault clay become very low. The decrease in shear strength of saturated fault clayis the major factor among the reasons for deformation. Numerical simulations using limit equilibriummodel, finite difference model and finite element model were performed for eight cross sections.Although safety factors are above 1.7 during the dry season, they become below 1.0 when groundwaterlevel raises to surface. The maximum displacement is about 15-3Ocm. However, safety factors increasedto above 2.4 and the maximum displacement is below 2.08cm after remedial treatment, Indicating thatthe slope becomes stable.

• Journal of Wetlands Research
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• v.19 no.1
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• pp.90-102
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• 2017

In this study, various types of nutrient models were tested by using two tears's water quality data collected from the stormwater wetland in Korea. Based on results, most important factor influencing nitrogen removal was hydraulic loading rate, which indicates that surface area of wetland is more important than its volumetric capacity, and model proposed by WEF was found to give a least error between measured and calculated values. For the phosphorus, in case assuming a power relationship between rate constant and temperature, the best prediction result were obtained, but temperature was most sensitive parameter affecting phosphorus removal. In addition, denitrification was always a limiting step for the nitrogen removal in this particular wetland mostly due to the lack of carbon source and high dissolved oxygen concentration. In this paper, several alternatives to improve nitrogen removal, including proper arrangement and designation of wetland elements and use of floating plants or synthetic fiber mat to control oxygen level and to capture the algal particles were proposed and discussed.

• KSBB Journal
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• v.21 no.4
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• pp.279-285
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• 2006

We investigated the effects of immobilization chemistry on the yield of immobilization and the bioactivity of the immobilized enzymes. Trypsin as a model protein and macroporous polymer beads(Toyopearl AF 650M, Tosho Co., Japan) was used as a model matrix. Four methods were used to immobilize trypsin; covalent conjugation by reductive amination(at pH 10.0 and pH 4.0) and affinity interaction via streptavidin-biotin, and double-affinity interaction via biotin-streptavidin-biotin system. The covalent conjugation immobilized $3{\sim}4$ mg/ml-gel, ca. 3-fold higher than the affinity method. However, the specific activity of the covalently(pH 10.0) and affinity-immobilized trypsin(via streptavidin-biotin) are ca. 37% and 50%, respectively, of that of the soluble enzyme(on the low-molecular-weight BAPNA substrate). When the molecular size of a substrate increased, the affinity-immobilized trypsin showed higher clavage activity on insulin and BSA. This result seemed to indicate the streptavidin-biotin system allowed more steric flexibility of the immobilized trypsin in its interaction with a substrate molecule. To confirm this, we studied the molecular flexibility of immobilized trypsin using quartz crystal microbalance-dissipation. Self-assembled monolayers were formed on the Q-sensor surface by aminoalkanethiols, and gultaraldehyde was attached to the SAMs. Trypsin was immobilized in two ways: reductive amination(at pH 10.0) and the streptavidin-biotin system. The dissipation shift of the affinity-immobilized trypsin was $0.8{\times}10^{-6}$, whereas that of the covalently attached enzyme was almost zero. This result confirmed that the streptavidin-biotin system allowed higher molecular flexibility. These results suggested that the bioactivity of the immobilized enzyme be strongly dependent on its molecular flexibility.

• Atmosphere
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• v.16 no.3
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• pp.247-257
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• 2006

The Yeong-dong heavy snowfall forecast supporting system has been developed during the last several years. In order to construct the conceptual model, we have examined the characteristics of heavy snowfalls in the Yeong-dong region classified into three precipitation patterns. This system is divided into two parts: forecast and observation. The main purpose of the forecast part is to produce value-added data and to display the geography based features reprocessing the numerical model results associated with a heavy snowfall. The forecast part consists of four submenus: synoptic fields, regional fields, precipitation and snowfall, and verification. Each offers guidance tips and data related with the prediction of heavy snowfalls, which helps weather forecasters understand better their meteorological conditions. The observation portion shows data of wind profiler and snow monitoring for application to nowcasting. The heavy snowfall forecast supporting system was applied and tested to the heavy snowfall event on 28 February 2006. In the beginning stage, this event showed the characteristics of warm precipitation pattern in the wind and surface pressure fields. However, we expected later on the weak warm precipitation pattern because the center of low pressure passing through the Straits of Korea was becoming weak. It was appeared that Gangwon Short Range Prediction System simulated a small amount of precipitation in the Yeong-dong region and this result generally agrees with the observations.

• Archives of Plastic Surgery
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• v.41 no.4
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• pp.317-324
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• 2014

Background Burn infliction techniques are poorly described in rat models. An accurate study can only be achieved with wounds that are uniform in size and depth. We describe a simple reproducible method for creating consistent burn wounds in rats. Methods Ten male Sprague-Dawley rats were anesthetized and dorsum shaved. A 100 g cylindrical stainless-steel rod (1 cm diameter) was heated to $100^{\circ}C$ in boiling water. Temperature was monitored using a thermocouple. We performed two consecutive toe-pinch tests on different limbs to assess the depth of sedation. Burn infliction was limited to the loin. The skin was pulled upwards, away from the underlying viscera, creating a flat surface. The rod rested on its own weight for 5, 10, and 20 seconds at three different sites on each rat. Wounds were evaluated for size, morphology and depth. Results Average wound size was $0.9957cm^2$ (standard deviation [SD] 0.1845) (n=30). Wounds created with duration of 5 seconds were pale, with an indistinct margin of erythema. Wounds of 10 and 20 seconds were well-defined, uniformly brown with a rim of erythema. Average depths of tissue damage were 1.30 mm (SD 0.424), 2.35 mm (SD 0.071), and 2.60 mm (SD 0.283) for duration of 5, 10, 20 seconds respectively. Burn duration of 5 seconds resulted in full-thickness damage. Burn duration of 10 seconds and 20 seconds resulted in full-thickness damage, involving subjacent skeletal muscle. Conclusions This is a simple reproducible method for creating burn wounds consistent in size and depth in a rat burn model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.5
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• pp.112-120
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• 2012

A numerical model considering the internal vaporization and the creep effect, in the form of a analytical program, for tracing the behavior of high strength concrete(HSC) members exposed to fire is presented. The two stages, i.e., spalling procedure and fire resistance time, associated with the thermal, moisture flow, creep and structural analysis, for the prediction of fire resistance behavior are explained. The use of the analytical program for tracing the response of HSC member from the initial pre-loading stage to collapse, due to fire, is demonstrated. Moisture evaporates, when concrete is exposed to fire, not only at concrete surface but also at inside the concrete to adjust the equilibrium and transfer properties of moisture. Finite element method is employed to facilitate the moisture diffusion analysis for any position of member, so that the prediction method of the moisture distribution inside the concrete members at fire is developed. The validity of the numerical model used in this program is established by comparing the predictions from this program with results from others fire resistance tests. The analytical program can be used to predict the fire resistance of HSC members for any value of the significant parameters, such as load, sectional dimensions, member length, and concrete strength.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.2
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• pp.79-93
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• 2015

Three-dimensional structures of large ocean rings in the Gulf Stream region are investigated using the HYbrid Coordinate Ocean Model (HYCOM). Numerically simulated flow structures around four selected cyclonic and anticyclonic rings are compared with two different horizontal resolutions: $1/12^{\circ}$ and $1/48^{\circ}$. The vertical distributions of Lagrangian Coherent Structures (LCSs) are analyzed using Finite Size Lyapunov Exponent (FSLE) and Okubo-Weiss parameters (OW). Curtain-shaped FSLE ridges are found in all four rings with extensions of surface ridges throughout the water columns, indicating that horizontal stirring is dominant over vertical motions. Near the high-resolution rings, many small-scale flow structures with size O(1~10) km are observed while these features are rarely found near the low-resolution rings. These small-scale structures affect the flow pattern around the rings as flow particles move more randomly in the high-resolution models. The dispersion rates are also affected by these small-scale structures as the relative horizontal dispersion coefficients are larger for the high-resolution models. The absolute vertical dispersion rates are, however, lower for the high-resolution models, because the particles tend to move along inclined eddy orbits when the resolution is low and this increases the magnitude of absolute vertical dispersion. Since relative vertical dispersion can reduce this effect from the orbital trajectories of particles, it gives a more reasonable magnitude range than absolute dispersion, and so is recommended in estimating vertical dispersion rates.