• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.120-137
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• 1997

Han's model, which is able to analyze optical communication between earth station and geo-satellite as a function of atmospheric conditions and elevation angles. is presented. In Han's model, atmospheric conditions are roughly classified into six basic types; clear sky, cloud, haze, fog, rain and snow. Data rate satisfying for the BER below $10^{-7}$ is analyzed by Han's model in case of up-link and down-link, respectively. Data rate is more limited by up-link than by down-link because the pointing loss caused by atmosphere on the up-link is greater than the spatial coherence degradation caused by atmosphere on the down-link.

• Information Systems Review
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• v.5 no.2
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• pp.183-202
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• 2003

In this paper, we designed an interoperability evaluation system based on technical reference model, HanTRM (Technical Reference Model) and the information technology architecture methodology, TAProcess (Technical Architecture Process). TAProcess provides standardized procedure and methodology for the efficient installation, management and operation of information technology. HanTRM can be used as a referencial basic framework for all organizations which are starting to make technical reference model. We propose a method that utilize HanTRM and a procedure that evaluates interoperability between information systems to design interoperbility evaluation system. So, this interoperbility evaluation system will be more usefully applied to organizations.

• Journal of Korea Water Resources Association
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• v.37 no.12
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• pp.1055-1063
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• 2004

An unsteady flow model is developed that allows variable roughness coefficient for each computational point according to its spatial position and the discharge. A step function or a power function can be used for functional relation between the discharge and the Manning's roughness coefficient. The model is applied to the reach of the South Han River between the Chungju Dam and Paldang Dam, and model parameters are estimated by optimization. Estimated parameters of both the step function model and the Power function model show that Manning's roughness coefficient decreases as the discharge increases. This tendency is more noticeable for the upstream reach of Yeoju compared to the downstream reach. It turns out that the stages calculated by the variable roughness coefficient model agree better with the observed ones than those by the conventional fixed parameter model.

• International conference on construction engineering and project management
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• 2015.10a
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• pp.620-621
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• 2015

In this study, the multi-criteria decision-making model based on Quality Function Deployment Method is proposed. Multicriteria decision-making is an attempt to link QFD method with the TOPSIS. By this effort, a model that makes client's decision-making more rational and objective in design phase is suggested. The multi-criteria decisionmaking model confirming to the Owner's requirements will improve the productivity of the construction industry and the satisfaction of the customer. Further study extending the range of the requirements, not only the Owner's requirement will be necessary to cover the various factors as much as possible. And then, finally as a flexible platform to achieve a sustainable quality management, web-based multi-criteria decision-making model can be utilized by the relevant stakeholders simultaneously with the feed-back and sharing the necessary informations.

• Journal of Korea Water Resources Association
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• v.34 no.2
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• pp.107-118
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• 2001

This study was to develop a tow-dimensional model system for the hydrodynamic analysis and to apply the system on the downstream of Han River. it is performed to design a GIS-based hydrodynamic system for the scientific shallow water profile analysis, and to compare hydrodraulic modeling is the Petrov-Galerkin's finite element method for flow prediction model. This study was to construct a GIS-based river flow system, and it is useful for supporting user's decision making for the on-line status through various analysis. We expect that the results from this study can be used as one of the guidelines for river analysis and management system in order rivers, reservoirs, and estuaries.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.1
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• pp.13-29
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• 2021

A 3-D hydrodynamic model is applied in the Han River Estuary system, Gyeonggi Bay, to understand the mechanisms of salt transport. The model run is conducted for 245 days (January 20 to September 20, 2020), including dry and wet seasons. The reproducibility of the model about variation of current velocity and salinity is validated by comparing model results with observation data. The salt transport (FS) is calculated for the northern and southern part of Yeomha channel where salt exchange is active. To analyze the mechanisms of salt transport, FS is decomposed into three components, i.e. advective salt transport derived from river flow (QfS0), diffusive salt transport due to lateral and vertical shear velocity (FE), and tidal oscillatory salt transport due to phase lag between current velocity and salinity (FT). According to the monthly average salt transport, the salt in both dry and wet seasons enters through the southern channel of Ganghwa-do by FT. On the other hand, the salt exits through the eastern channel of Yeongjong-do by QfS0. The salt at Han River Estuary enters towards the upper Han River by FT in dry season, whereas that exits to the open sea by QfS0 in wet season. As a result, mechanisms of salt transport in the Han River Estuary depend on the interaction between QfS0 causing transport to open sea and FT causing transport to the upper Han River.

• Journal of the Korean Society for Nondestructive Testing
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• v.13 no.1
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• pp.21-28
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• 1993

If the infinitesimal delamination exists and the two waves can hardly be distinguished from each other on account of being much closer, we cannot measure the thickness of delamination by the time difference method. On this study, we calculated the thickness of infinitesimal delamination model by means of measuring echo height due to the deflection of material particles and utilized Newton Ring for optical measurement as a delamination model. From the result of Newton Ring expressed in the delamination model, we can calculate the infinitesimal delamination thickness up to $0.2{\sim}0.3{\mu}m$ due to the difference of acoustic impedance by the ratio of the echo height to the total reflection.

• Communications for Statistical Applications and Methods
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• v.8 no.3
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• pp.753-765
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• 2001

We suggest a quantitative conditional unrelated question model that can be used in obtaining more sensitive information. For whom say "yes" about the less 7han sensitive question .B we ask only about the more sensitive variable X. We extend our model to two sample case when there is no information about the true mean of the unrelated variable Y. Finally we compare the efficiency of our model with that of Greenberg et al.′s.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.83-84
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• 2010

• Journal of Industrial Technology
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• v.20 no.A
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• pp.73-82
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• 2000

This study was implemented to find an optimal model for wastewater treatment processes using PHOENICS(Parabolic, hyperbolic or Elliptic Numerical Integration Code Series) and ASM(Activated Sludge Model). PHOENICS is a general software based upon the laws of physics and chemistry which govern the motion of fluids, the stresses and strains in solids, heat flow, diffusion, and chemical reaction. The wastewater flow and removal efficiency of particle in two phase system of a grit chamber in wastewater treatment plant were analyzed to inquire the predictive aspect of the operational model. ASM was developed for a biokinetic model based upon material balance in complex activated sludge systems, which can demonstrate dynamic and spatial behavior of biological treatment system. This model was applied to aeration tank and settling chamber in Choonchun city, and the modeling result shows dynamic transport in aeration tank. PHOENCS and ASM could be contributed for the optimal operation of wastewater treatment plant.