• Journal of the Korea Society of Computer and Information
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• v.25 no.11
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• pp.211-218
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• 2020

Gwangju Airport and Muan International Airport are planned to merge in 2021 while the aviation market is suffering an unprecedented prolonged crisis due to COVID-19 and therefore it is necessary to revitalize the airport to keep up with the passenger's demands. The study conducts an empirical research survey on the passengers of both airports regarding the importance, satisfaction, and overall satisfaction to derive a strategic marketing direction. The results show that to establish a strategic marketing direction, an urgent improvement is required for all "Commercial Facility and Diversity," "Rest Facility and Comfort," "Facilities for the Transportation Vulnerable," "Latest Facility" factors, and "Air Route Diversity." On the other hand, it is required to stop further investing and improving in "Publicity and Marketing" and "Flight Schedule". The results of this study demonstrate academic and practical importance through the comparison of two IPA models, based on Gwangju Airport and Muan International Airport before their integration, to provide substantive and meaningful marketing strategies.

• Journal of the Korean Geotechnical Society
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• v.27 no.3
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• pp.75-83
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• 2011

Emerging issues related with fully coupled Thermo-Hydro-Mechanical (THM) behavior of unsaturated soil demand the development of a numerical tool in diverse geo-mechanical and geo-environmental areas. This paper presents general governing equations for coupled THM processes in unsaturated porous media. Coupled partial differential equations are derived from three mass balances equations (solid, water, and air), energy balance equation, and force equilibrium equation. With Galerkin formulation and time integration of these governing equations, finite element code is developed to find nonlinear solution of four main variables (displacement-u, gas pressure-$P_g$), liquid pressure-$P_1$), and temperature-T) using Newton's iterative scheme. Three cases of numerical simulations are conducted and discussed: one-dimensional drainage experiments (u-$P_g-P_1$), thermal consolidation (u-$P_1$-T), and effect of pile on surrounding soil due to surface temperature variation (u-$P_1$-T).

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.2
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• pp.432-445
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• 1994

From a theoretical analysis point of view, the 2-stage precipitator is decomposed into two units: charging cell and collecting cell. Collection efficiency predictions of the two-stage parallel-plate electrostatic precipitator have been performed theoretically incorporating with the charging and the collecting cells. Particle trajectorise passing the charging cell have been modeled as a simple one. Particle charge distribution at the outlet of the charging cell is calculated through integration of the present unipolar combined charging rate along the entire particle trajectory, and average charge of particles at the outlet of the charging cell is obtained from the particle charge distribution. As for the collecting cell, the diminution of particle concentration along the longitudinal direction of the collecting cell is investigated considering the conventional Deutsch's theory and the laminar theory. One should note that the collection efficiency formula derived is based on monodisperse aerosols. It has been confirmed through the analysis that predictions of particle charge by applying White's unipolar diffusion charging theory overpredict actual cases in the continuum regime, while predictions by Fuch's unipolar diffusion charging theory indicate the reasonable result in the same regime. Theoretical predictions of collection efficiency are also compared with the available experimental results. Comparisons show that the experimental results are consistently located in the collection efficiency region bounded by the two limits, the Deutsch and the laminar collection efficiencies. Finally design parameters of the 2-stage electrostatic precipitator have been investigated systematically through the one-variable-at-a-time method in terms of collection efficiency. Applied voltages on the corona wire of the charging cell and the plate of the collecting cell, and the average air velocity have been selected as the design parameters.

• Korean Journal of Materials Research
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• v.23 no.6
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• pp.334-338
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• 2013

In this study, $BaTiO_3$ thin films were grown by RF-magnetron sputtering, and the effects of the thin film thickness on the structural characteristics of $BaTiO_3$ thin films were systematically investigated. Instead of the oxide substrates generally used for the growth of $BaTiO_3$ thin films, p-Si substrates which are widely used in the current semiconductor processing, were used in this study in order to pursue high efficiency in device integration processing. For the crystallization of the grown thin films, annealing was carried out in air, and the annealing temperature was varied from $700^{\circ}C$. The changed thickness was within 200 nm~1200 nm. The XRD results showed that the best crystal quality was obtained for ample thicknesses 700 nm~1200 nm. The SEM analysis revealed that Si/$BaTiO_3$ are good quality interface characteristics within 300 nm when observed thickness. And surface roughness observed of $BaTiO_3$ thin films from AFM measurement are good quality surface characteristics within 300 nm. Depth-profiling analysis through GDS (glow discharge spectrometer) showed that the stoichiometric composition could be maintained. The results obtained in this study clearly revealed $BaTiO_3$ thin films grown on a p-Si substrate such as thin film thickness. The optimum thickness was 300 nm, the thin film was found to have the characteristics of thin film with good electrical properties.

• Atmosphere
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• v.26 no.1
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• pp.35-45
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• 2016

Initialization of the global seasonal forecast system is as much important as the quality of the embedded climate model for the climate prediction in sub-seasonal time scale. Recent studies have emphasized the important role of soil moisture initialization, suggesting a significant increase in the prediction skill particularly in the mid-latitude land area where the influence of sea surface temperature in the tropics is less crucial and the potential predictability is supplemented by land-atmosphere interaction. This study developed a new soil moisture initialization method applicable to the KMA operational seasonal forecasting system. The method includes first the long-term integration of the offline land surface model driven by observed atmospheric forcing and precipitation. This soil moisture reanalysis is given for the initial state in the ensemble seasonal forecasts through a simple anomaly initialization technique to avoid the simulation drift caused by the systematic model bias. To evaluate the impact of the soil moisture initialization, two sets of long-term, 10-member ensemble experiment runs have been conducted for 1996~2009. As a result, the soil moisture initialization improves the prediction skill of surface air temperature significantly at the zero to one month forecast lead (up to ~60 days forecast lead), although the skill increase in precipitation is less significant. This study suggests that improvements of the prediction in the sub-seasonal timescale require the improvement in the quality of initial data as well as the adequate treatment of the model systematic bias.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.24 no.1
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• pp.1-9
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• 2016

In this paper, we integrate three degree of freedom(3DOF) point-mass model for aircraft and three-dimensional path generation algorithms using dubins curve and nonlinear path tracking law. Through this integration, we apply the path generation algorithm to the path planning, and verify tracking performance and feasibility of using the aircraft 3DOF point-mass model for air traffic management. The accuracy of modeling 6DOF aircraft is more accurate than that of 3DOF model, but the complexity of the calculation would be raised, in turn the rate of computation is more likely to be slow due to the increase of degree of freedom. These obstacles make the 6DOF model difficult to be applied to simulation requiring real-time path planning. Therefore, the 3DOF point-mass model is also sufficient for simulation, and real-time path planning is possible because complexity can be reduced, compared to those of the 6DOF. Dubins curve used for generating the optimal path has advantage of being directly available to apply path planning. However, we use the algorithm which extends 2D path to 3D path since dubins curve handles the two dimensional path problems. Control law for the path tracking uses the nonlinear path tracking laws. Then we present these concomitant simulation results.

• Journal of Environmental Impact Assessment
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• v.12 no.1
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• pp.23-34
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• 2003

The emergency response modeling system CARIS has been developed at CCSM (Center for Chemical Safety Management), NIER (National Institute of Environmental Research) to track and predict dispersion of hazardous chemicals for the environmental decision support in case of accidents at chemical or petroleum companies in Korea. The main objective of CARIS is to support making decision by rapidly providing the key information on the efficient emergency response of hazardous chemical accidents for effective approaches to risk management. In particular, the integrated modeling system in CARIS consisting of a real-time numerical weather forecasting model and air pollution dispersion model is supplemented for the diffusion forecasts of hazardous chemicals, covering a wide range of scales and applications for atmospheric information. In this paper, we introduced the overview of components of CARIS and described the operational modeling system and its configurations of coupling/integration in CARIS. Some examples of the operational modeling system is presented and discussed for the real-time risk assessments of hazardous chemicals.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.214.2-214.2
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• 2013

Device performance for the 45 and 32 nm node CMOS technology requires the integration of ultralow-k materials. To lower the dielectric constant for PECVD and spin-on materials, partial replacement of the solid network with air (k=1.01) appears to be more intuitive and direct option. This can be achieved introducting of second "labile" phase during depositoin that is removed during a subsequent UV curing and annealing step. Besides, with shrinking line dimensions the resistivity of barrier films cannot meet the International Technology Roadmap for Semiconductors (ITRS) requirements. To solve this issue self-forming diffusion barriers have drawn attention for great potential technique in meeting all ITRS requirments. In this present work, we report a Cu-V alloy as a materials for the self-forming barrier process. And we investigated diffusion barrier properties of self-formed layer on low-k dielectrics with or without UV curing treatment. Cu alloy films were directly deposited onto low-k dielectrics by co-sputtering, followed by annealing at various temperatures. X-ray diffraction revealed Cu (111), Cu (200) and Cu (220) peaks for both of Cu alloys. The self-formed layers were investigated by transmission electron microscopy. In order to compare barrier properties between V-based interlayer on low-k dielectric with UV curing and interlayer on low-k dielectric without UV curing, thermal stability was measured with various heat treatment temperature. X-ray photoelectron spectroscopy analysis showed that chemical compositions of self-formed layer. The compositions of the V based self-formed barriers after annealing were strongly dominated by the O concentration in the dielectric layers.

• Journal of the Korea Convergence Society
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• v.10 no.6
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• pp.15-24
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• 2019

The development of "New Retailing" is still in its infancy. Theoretical research has just begun, showing the characteristics of practice leading theoretical research, that is, there is more practical exploration but relatively insufficient theoretical research. At present, the theoretical research and practice development of "New Retailing" is gradually clear. The future development trend is large-scale, no boundaries, and wisdom. The academic community should further study in depth with theory and practice, focusing on the deep integration of online and offline, the new logistics under "New Retailing", and the research direction of "New Retailing" driving supply chain transformation and reconstruction so as to better guide the development of "New Retailing". The purpose of the research is to sort out the research status and theoretical situation of "new retailing", so as to provide references for further research on "new retail" and guidance for practical development.

• Korean Journal of Remote Sensing
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• v.35 no.1
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• pp.57-81
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• 2019

Satellite images can be integrated into a crop model to strengthen the advantages of each technique for crop monitoring and to compensate for weaknesses of each other, which can be systematically applied for monitoring inaccessible croplands. The objective of this study was to outline the productivity of paddy rice based on simulation of the yield of all paddy fields in North Korea, using a grid crop model combined with optical satellite imagery. The grid GRAMI-rice model was used to simulate paddy rice yields for inaccessible North Korea based on the bidirectional reflectance distribution function-adjusted vegetation indices (VIs) and the solar insolation. VIs and solar insolation for the model simulation were obtained from the Geostationary Ocean Color Imager (GOCI) and the Meteorological Imager (MI) sensors of the Communication Ocean and Meteorological Satellite (COMS). Reanalysis data of air temperature were achieved from the Korea Local Analysis and Prediction System (KLAPS). Study results showed that the yields of paddy rice were reproduced with a statistically significant range of accuracy. The regional characteristics of crops for all of the sites in North Korea were successfully defined into four clusters through a spatial analysis using the K-means clustering approach. The current study has demonstrated the potential effectiveness of characterization of crop productivity based on incorporation of a crop model with satellite images, which is a proven consistent technique for monitoring of crop productivity in inaccessible regions.