• Tunnel and Underground Space
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• v.10 no.1
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• pp.25-32
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• 2000

This paper presents two new extensions to the DDA method. The extensions consist of sequential loading or unloading and rock reinforcement by rockbolts, shotcrete or concrete lining. Examples of application of the DDA method with the new extensions are presented. Simulations of the underground excavation of the Unju Tunnel of Kyungbu High Speed Railway Project in Korea were carried out to evaluate the influence of excavation sequence and reinforcement on the tunnel stability. The results of the present study indicate that improper selection of excavation sequence could have a destabilizing effect on the tunnel stability. On the other hand, reinforcement by rockbolts and shotcrete can stabilize the tunnel. It is found that, in general, the DDA program with the three new extensions can now be used as d practical tool in the design of underground structures. In particular, phases of construction (excavation, reinforcement) can now be simulated more realistically.

• The Transactions of the Korea Information Processing Society
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• v.3 no.1
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• pp.95-106
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• 1996

The most fundamental difference between general three dimensional computer graphics technology and virtual reality technology lies in the degree of realism as we feel, and thus the virtual reality method heavily relies on such tolls as data gloves, 3D auditory system to enhance human perception and recognition. Although these tolls are valid for such purpose, more essential ingredient. This paper provides further realism by modeling active interactions between the objects inside scenes. For this purpose, this paper proposes and implements a field model where the virtual reality space is treated as a physical field defined on the characteristic radius of stimulus and sense corresponding to the individual object. In the field model, the rule of cause and effect as an essential feature of the realism can be interpreted simply as an energy exchange between objects and consequently, variation on the radius information together with behavioral logic alone can build the virtual environment where each object can react to other objects actively and controllably.

• Journal of the korean society of oceanography
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• v.39 no.1
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• pp.46-56
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• 2004

Spectral attenuation of light and upwelling radiance were measured in the western coast of Korea on board the R/V Inchon 888 of the Korean National Fisheries Research and Development Institute(NFRDI) during four seasons. The goal of these efforts was to determine the spatial and temporal distribution of the inherent and apparent optical properties of the water, and the factors that control their distribution. Our data indicate that while stratification of the water column, phytoplankton, and wind stress determined the vertical distribution of the optical parameters offshore, it was the tidal current and sediment type that controlled both the vertical and horizontal distribution in the coastal areas. These findings led to the development of a model that estimates the spectral attenuation of light with respect to depth and time for the Yellow Sea. The model integrates water leaving radiance from satellites, sediment types, current vectors, sigma-t, bathymetry, and in situ optical measurements in a learning algorithm capable of extracting optical properties with only knowledge of the environmental conditions of the Yellow Sea. The performance of the model decreases with increase in depth. The mean absolute percentage error (MAPE) of the model is 2% for the upper five meters, 8-10% between 6 and 50 meters, and 15% below 51 meters.

• Economic and Environmental Geology
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• v.17 no.1
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• pp.49-55
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• 1984

This paper describes three-dimensional (3-D) standard curves for conductive dipping buried bodies in induced polarization (IP) method. Dipole-dipole IP responses for the dipping bodies are calculated by the numerical modeling technique using an integral equation solution. Dip angles of the bodies are 0, 20, 45, 70 and 90 degrees, respectively. The horizontal (0-degree dip) and vertical (90-degree dip) bodies produce symmetrical patterns of IP responses. The dipping bodies of 20, 45 and 70 degrees, however, produce asymmertical patterns, with the highest IP contours dipping in the direction opposite to the bodies in pseudo-sections. The most remarkable asymmetrical pattern appears in the model of 20-degree dip. It is difficult to distinguish the body of 70-degree dip from that of 90-degree dip on the basis of dipole-dipole IP data. The IP pattern in pseudo-sections varies when the line moves away from the center of the body along strike, with the anomaly deeper and smaller in amplitude. IP maps seem to be more useful than IP pseudo-sections in predicting the location of target.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.31 no.5
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• pp.411-419
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• 2013

Research on developing algorithms for building modeling such as extracting outlines of the buildings and segmenting patches of the roofs using aerial images or LiDAR data are active. However, utilizing information from the building model is not well implemented yet. This study aims to propose a scheme for search identical or similar shape of buildings by utilizing graph topology pattern matching under the assumptions: (1) Buildings were modeled beforehand using imagery or LiDAR data, or (2) 3D building data from digital maps are available. Side walls, segmented roofs and footprints were represented as nodes, and relationships among the nodes were defined using graph topology. Topology graph database was generated and pattern matching was performed with buildings of various shapes. The results show that efficiency of the proposed method in terms of reliability of matching and database structure. In addition, flexibility in the search was achieved by altering conditions for the pattern matching. Furthermore, topology graph representation could be used as scale and rotation invariant shape descriptor.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.102-114
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• 2004

The present work has been developed the interpretation processor including the behavior of material failure and the separation phenomena under transient dynamic loading (the operation of explosive bolt) using AUTODYN V4.3, SoildWork 2003 and TrueGrid V2.1 programs. It has been demonstrated that the interpretation in ridge-cut explosive bolt under dynamic loading condition should be necessary to the appropriate failure model and the basic stress of bolt failure is the principal stress. The use of this interpretation processor developing the present work could be extensively helped to design the shape and the amount of explosives in the explosive bolt having a complex geometry. It is also proved that the interpretation processor approach is an accurate and effective analysis technique to evaluate the separation mechanism in explosive bolts.

• Computers and Concrete
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• v.18 no.3
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• pp.297-317
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• 2016

Current codes recommend large amounts of shear reinforcement for reinforced concrete beam-column joints that causes significant bar congestion. Increase in congestion of shear reinforcement in joint core (connection zone), leads to increase accomplishment problems. The congestion may also lead to diameter limitations on the beam bars relative to the joint dimensions. Using double headed studs instead of conventional closed hoops in reinforced concrete beam-column joints reduces congestion and ensures easier assembly of the reinforcing cage. The purpose of this research is evaluating the efficiency of the proposed reinforcement. In this way, 10 groups of exterior beam-column joints are modeled. Each group includes 7 specimens by different reinforcing details in their joint core. All specimens are modeled by using of ABAQUS and analyzed subjected to cyclic loading. After verification of analytical modeling with an experimental specimen, 3D nonlinear specimens are modeled and analyzed. Then, the effect of amount and arrangement of headed studs on ductility, performance, ultimate strength and energy absorption has been studied. Based on the results, all joints reinforced with double headed studs represent better performance compared with the joints without shear transverse reinforcement in joints core. The behavior of the former is close to joints reinforced with closed hoops and cross ties according to the seismic design codes. By adjusting the arrangement of double-headed studs, the decrease in ductility, performance, ultimate moment resistant and energy absorption reduce to 2.61%, 0.90%, 0.90% and 1.66% respectively compared with the joints reinforced by closed hoops on the average. Since the use of headed studs reduces accomplishment problems, these amounts are negligible. Therefore, use of double-headed studs has proved to be a viable option for reinforcing exterior beam-column joints.

• Journal of the Korean Society of Groundwater Environment
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• v.6 no.2
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• pp.101-106
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• 1999

Open dump of refuse causes groundwater and soil contamination by leachate and air pollution by LFG(Landfill Gas). In this paper, in order to perform a study about reduction of high leachate and LFG collection & control, using a 3-D, 2-phase, transient FDM model, the analysis of simultaneous flow of leachate and LFG has been carried out. In present numerical analysis it is assumed that 58 percents of LFG will evaporate to the ambient air and the recharge rate of a landfill be 12 percent of the average precipitation per year. All other data were excerpted at the point of 1995 when three refuse layers had been buried. From numerical analysis we concluded that maximum head value is approximately 26 mH2O<-에이치투오 (2.52 atm) in the center of the system and that installing venting trench plays an important role in landfill stabilization. Evan with the assumption of three layers constructed and low recharge rate applied, it is found that cumulative leachate and LFG productions will be 15.1 million 세제곱미터, 5.58 billion 세제곱미터, respectively after 40 years.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.1
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• pp.15-22
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• 2009

This study reports the serial use of a 3-D hydrodynamic model, EFDC-Hydro and a dynamic water quality model WASP7.2 that are maintained by USEPA. The 48 km section of the Geum River downstream between Daechung Dam and Gongju was selected as a sample study site. Topographical information was used to accurately represent morphology of the study site and boundary conditions were derived from governmental databases including WAMIS by Ministry of Land and Ocean and WEIS by Ministry of Environment. EFDC-Hydro was successfully calibrated for observed water level and WASP was calibrated using monthly observed water quality data obtained from the above sources. It was found that the current water quality target of BOD for the Geum River-H point could not be met on monthly basis though every other tributary of the area would meet its own water quality target as assigned in Korean TMDL. This study proposed the new target BOD water quality for the Gabcheon and Mihocheon as 4.3 and 3.6 mg/l, respectively so that the Geum River-H point can meet the target. When Sejong City is constructed, it is estimated that effluent discharge limit of BOD must be less than 4.5 mg/l to meet water quality of the point. This study shows that it is possible to carry out more precise modeling considering both water movement and water kinetics by using EFDC and WASP simultaneously.

• Korean Journal of Clinical Pharmacy
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• v.22 no.3
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• pp.228-233
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• 2012

Purpose: The purpose of this study was to elucidate the effect of dissolved oxygen in alcohol to blood pressure of healthy persons. Methods: Subjects (n=30) were randomized in a double blind crossover study to receive 120 mL, 240 mL, 360 mL of alcohol (Korean spirit, 19.59 v/v%, dissolved oxygen is 8 ppm and 20 ppm). Blood alcohol concentration (BAC) and blood pressure were measured applying Lion SD-400 Alcolmeter$^{(R)}$ Breathalyser and Tensoval duo control. Pharmacokinetic parameters ($C_{max}$, $T_{max}$, $AUC_{last}$, $K_{el}$, $V_d$, Clearance) were calculated using Winnonlin$^{(R)}$ program. The difference of parameters and values were analysed by student t-test using Microsoft$^{(R)}$ Excel program. Results: The $AUC_{last}$ values of 8 ppm group and 20 ppm group in 240 ml administration were $6.15{\pm}2.60cg{\cdot}min/ml$, $5.33{\pm}1.84cg{\cdot}min/ml$ (p<0.05) and those in 360 mL were $11.93{\pm}5.70cg{\cdot}min/ml$, $10.33{\pm}4.60cg{\cdot}min/ml$ (p < 0.01), respectively. Thus, the $AUC_{last}$ was significantly decreased. On the other hands, there was a significant change in systolic blood pressure (SBP) after alcohol administration. All measured value after 360 mL of alcohol administration was significantly decreased (p < 0.01). Conclusions: The dissolved oxygen in alcoholic beverage has no effect on blood pressures but the alcohol administration has an effect on blood pressure. Thus, SBP can be used as a biomarker of alcohol administration and utilized in PK/PD modeling of alcohol.