• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.102-109
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• 1993

A PC-computer program RADAP has been developed in this study to perform a quick real-time analysis of dose assessment following an accident in a nuclear facility. RADAP uses an interactive LKagrangian puff model in simulating the transport and diffusion of radioactive plume in the atmosphere. For real-time analysis, RADAP treats one or multiple puffs of ground-level releases, simultaneously. It is assumed to maintain a Gaussian distribution within the puff and the diffusion coefficients are computed using the USNRC's normal sigma curve method. The program, however, does not consider the spatial variations but the temporal variations in wind conditions. Whole body and thyroid doses for 3$\times$31 grid are directed to output files, and they are also displayed through computer graphics on VGA or EGA color monitor. The results show that RADAP can be an excellent tool for quick estimation of accidental doses.

• The Journal of Korean Physical Therapy
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• v.34 no.6
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• pp.326-331
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• 2022

Purpose: The stroke patients have gait dysfunction due to impaired neural tracts; corticospinal tract (CST), corticoreticular pathway (CRP), and vestibulospinal tract (VST). In this study, we investigated characteristics of gait pattern according to the injury aspect of the neural track in a stroke patient. Methods: One patient and six control subjects of similar age participated. A 19-year-old male patient with spontaneous intracerebral hemorrhage on right basal ganglia, thalamus, corona radiata and cerebral cortex due to arteriovenous malformation rupture. Diffusion tensor imaging (DTI) data was acquired 21 months after the stroke. Kinematic and spatio-temporal parameters of gait were collected using a three-dimensional gait analysis system. Results: On 21 months DTI, the CST and CRP in affected hemisphere showed severe injury, in contrast, the VST in affected hemisphere showed intact integrity. Result of gait analysis, walking distance and speed were significantly decreased in a patient. The stance rate of unaffected lower limb, the swing rate of affected lower limb and the duration of double stance significantly increased compared with normal control. The knee and hip joint angle were significantly decreased in a patient. Conclusion: We found recovered independent gait ability may be associated with unimpaired VST in a patient with severe injury in CST and CRP.

• Geomechanics and Engineering
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• v.34 no.2
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• pp.155-171
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• 2023

Aiming at the grouting treatment of water inflow in karst conduits, a visualized experiment system for conduit-type grouting blocking was developed. Through the improved water supply system and grouting system, and the optimized multisource information monitoring system, the real-time observation of diffusion and deposition of slurry, and the data acquisition of pressure and velocity during the whole process of grouting were realized, which breaks through the problem that the monitoring element is easy to fail due to slurry adhesion in conventional test system. Based on the grouting experiments in static and flowing water, the diffusion and deposition behavior of the quick-setting slurry under different working conditions were analyzed. The temporal and spatial variation behavior of the pressure and velocity were studied, and the blocking mechanism of the grouting were further revealed. The results showed that: (1) Under the flowing water condition, the counter-flow diffusion distance of slurry was negatively correlated with the flow water velocity and the volume ratio of cement and sodium silicate (C-S ratio), and positively correlated with the grouting volume. The slurry deposition thickness was negatively correlated with the flowing water velocity, and positively correlated with the grouting volume and C-S ratio. (2) The pressure increased slowly before blocking of the flowing water and rapidly after blocking in karst conduits. (3) With the continuous progress of grouting, the flowing water velocity decreased slowly first, then significantly, and finally tended to be stable. According to the research results, some engineering recommendations were put forward for the grouting treatment of the conduit-type water inflow disaster, which has been successfully applied in the treatment project of the China Resources Cement (Pingnan) Limestone Mine. This study provided some guidance and reference for the parameter optimization of grouting for the treatment projects of water inflow in karst conduits.

• Journal of Korean Port Research
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• v.9 no.1
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• pp.45-56
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• 1995

Investigation of the physical behavior of dredged material disposal in coastal water includes estimations of water column concentration in the receiving water, exposure time, the initial deposition pattern as well as thickness of material at the dumping fields near the estuary area. Calculation based on vertical setting and horizontal advection of single particles ignore the effects of bulk properties of the disposed material, vertical and horizontal diffusion, and material dilution due to the entrainment of ambient water during descent. This paper focuses on the spatial and temporal changes in the dumping fields for the water column and bottom at a hypothetically confined coastal water, where the ambient time-invariant velocity and density profiles are applied, within the initial time period following the instantaneous release of the dredged material. This model accounts the behavior of material after release divided into three phases: convective descent, dynamic collapse and long-term passive dispersion

• Journal of Korean Neurosurgical Society
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• v.46 no.1
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• pp.74-76
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• 2009

We present an extremely rare case of the atypical choroid plexus papilloma in an adult which developed at the trigone of right lateral ventricle. A 62-year-old woman presented with the history of intermittent and gradually progressive headache and left side hemiparesis for 6 months. The brain magnetic resonance image showed highly enhanced and well demarcated mass at the trigone of lateral ventricle attached to the choroid plexus. Gross total resection was performed by transcortical approach via the middle temporal gyrus. The tumor was diagnosed as an atypical choroid plexus papilloma. She had no neurologic deficit after the surgery. We report a case of atypical choroid plexus papilloma in adult and introduce newly classified pathologic characteristics of this tumor.

• 한국전산유체공학회:학술대회논문집
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• 2000.10a
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• pp.129-134
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• 2000

An efficient numerical method to solve the unsteady incompressible Navier-Stokes equations is developed. A fully implicit time advancement is employed to avoid the CFL(Courant-Friedrichs-Lewy) restriction, where the Crank-Nicholson discretization is used for both the diffusion and convection terms. Based on a block LU decomposition, velocity-pressure decoupling is achieved in conjunction with the approximate factorization. Main emphasis is placed on the additional decoupling of the intermediate velocity components with only n th time step velocity The temporal second-order accuracy is Preserved with the approximate factorization without any modification of boundary conditions. Since the decoupled momentum equations are solved without iteration, the computational time is reduced significantly. The present decoupling method is validated by solving the turbulent minimal channel flow unit.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.685-688
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• 2004

Fresh water discharge from the sea floor strongly affects a coastal ecology and the diffusion of contaminants. Much fresh water discharge has been found in the edge of Kurobe alluvial fan, in which annual rainfall is over 4000mm and there is abundant groundwater. However, it is difficult to find the groundwater discharge, thus the search of possible areas with some remote sensing tools is required. Because the temperature of the discharge point is relatively low compared with the surrounding sea water surfaces, there is a possibility to detect the area as an irregular zone of thermal infrared images. Two anomalous temperature zones, which have no surface streams from rivers, are detected by ASTER thermal-infrared images. One of them was verified as the groundwater discharge point by dives. In addition, the distribution of water table under the land side of the two areas is also detected as irregular zones by a ground-penetrating radar

• Journal of ILASS-Korea
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• v.15 no.2
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• pp.67-73
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• 2010

The capability of pilot injection with small fuel quantity at all engine operating conditions is one of the main feature of the common rail direct injection system. The purpose of the pilot injection is to lower the engine noise and to reduce the NOx emissions. This study describes the pilot spray structure characteristics of the common-rail diesel injectors with different electric driving characteristics, including solenoid-driven and piezo-driven type. Namely three common-rail injectors with different electric current wave were investigated in this study. The pilot spray characteristics such as spray speed, spray tip penetration, and spray angle were obtained by spray images, which is measured by the back diffusion light illumination method with optical system for high-speed temporal photography. As this research results, it was found that pilot injection of common-rail system was effected by rate of injection with different electrical characteristic for injector driving.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.29 no.6 s.237
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• pp.703-710
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• 2005

A finite element discretization of the advection and redistancing equations of level set method has been studied. It has been shown that Galerkin spatial discretization combined with Crank-Nicolson temporal discretization of the advection equation of level set yields a good result and that consistent streamline upwind Petrov-Galerkin(CSUPG) discretization of the redistancing equation gives satisfactory solutions for two test problems while the solutions of streamline upwind Petrov-Galerkin(SUPG) discretization are dissipated by the numerical diffusion added for the stability of a hyperbolic system. Furthermore, it has been found that the solutions obtained by CSUPG method are comparable to those by second order ENO method.

• Journal of Construction Engineering and Project Management
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• v.2 no.4
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• pp.32-41
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• 2012

In recent times, multi-centralization and decentralization as well as large Capital area and suburbanization in the spatial structure of capital area. With rapid growth, urbanization and industrialization are unsystematic, and growth inequality between regions caused negative effects such as discordant centralization and decentralization, fluctuating land value, and gap between living conditions. Accordingly, this study analyzed urban spatial indexes by the self-governed body in the capital area such as Seoul, Incheon, and Gyeonggi province for the analysis of the regional inequality phenomenon. We examined the characteristics of temporal and spatial changes in urban spatial structure in the capital area by utilizing the distribution pattern and density of city indexes such as population, employment, etc, and then drew the commonality of those factors through factor analysis. We evaluated the drawn results through the city standard index by each city, conducted factor score analysis, and identified the interaction between each factor and Housing Purchase Price Composite Indices index, housing rent price index(Housing Jeonse Price Composite Indices), land price fluctuation rate, diffusion ratio of house, and financial independence.