• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2002.05a
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• pp.608-612
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• 2002

An automatic face and facial feature points(FFPs) detection system is proposed. A face is represented as a graph where the nodes are placed at facial feature points(FFPs) labeled by their Gabor features md the edges are describes their spatial relations. An innovative flexible feature matching is proposed to perform features correspondence between models and the input image. This matching model works likes random diffusion process in the image spare by employing the locally competitive and globally corporative mechanism. The system works nicely on the face images under complicated background, pose variations and distorted by facial accessories. We demonstrate the benefits of our approach by its implementation on the fare identification system.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.9
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• pp.773-778
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• 2001

In this dissertation the results of the combined experimental and theoretical studies designed to understand and predict the spatial growth and transport coefficients for electrons in SF$_{6}$ and SF$_{6}$-Ar mixtures have described. The ionization and attachment coefficients in pure SF$_{6}$ and SF$_{6}$-Ar mixtures have been calculated over the range of 10$_{6}$ molecule and for Ar atom proposed by other authors. The transport coefficients for electrons in (0.2%)SF$_{6}$-Ar and (0.5%)SF$_{6}$-Ar mixtures were measured by time-of-flight method, and the electron energy distribution function and the parameters of the velocity and the diffusion were determined by the variation of the collision cross-sections with energy. The results obtained in this work will provide valuable information on the fundamental haviors of electrons in weakly ionized gases and the role of electron attachment in the choice of better gases and unitary gas dielectrics or electro negative components in dielectric gas mixtures. gas mixtures.

• Computers and Concrete
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• v.19 no.2
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• pp.143-152
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• 2017

This paper has numerically investigated the changes of loading-induced stress in concrete with the corrosion time in the sulfate-containing environment. Firstly, based on Fick's law and reaction kinetics, a diffusion-reaction equation of sulfate ion in concrete is proposed, and it is numerically solved to obtain the spatial and temporal distribution of sulfate ion concentration in concrete by the finite difference method. Secondly, by fitting the existed experimental data of concrete in sodium sulfate solutions, the chemical damage of concrete associated with sulfate ion concentration and corrosion time is quantitatively presented. Thirdly, depending on the plastic-damage mechanics, while considering the influence of sulfate attack on concrete properties, a simplified chemo-mechanical damage model, with stress-based plasticity and strain-driven damage, for concrete under axial loading and sulfate attack is determined by introducing the chemical damage degree. Finally, an axially compressed concrete prism immersed into the sodium sulfate solution is regarded as an object to investigate the time-varying stress in concrete subjected to the couplings of axial loading and sulfate attack.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.907-912
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• 2009

Complex breakup behavior in the revival wave has been observed in the Belousov-Zhabotinsky(BZ) reaction system containing 1,4-cyclohexanedione (1,4-CHD) in the dish divided into two compartments with a sliding window. A same reaction mixture is poured into the two compartments individually with time difference. Wave propagation exhibited different behavior in the revival wave of the reaction system. This was largely dependent on the progress time prior to the pouring into each compartment and on the gap between the times of pouring into the two compartments. The revival wave in the reaction system is induced spontaneously as a new wave train with a long time lag after the disappearance of the initially induced wave. A thoroughgoing study of the chaotic breakup of propagating chemical wave train was to be possible since the revival wave has a longer wavelength, clearer wave-train patterns, and longer duration period.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.20-27
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• 1993

This paper concerns with developing a simplified in-core fuel management scoping tool for PWR. For this purpose the point reactivity model is put into a fuel cycling decision code, FCYPRM. Modified Borresen's coarse-mesh diffusion theory and nodal expansion method are utilized to form a spatial neutron analysis code, CMSNAP. Numerical experiments are per- formed to determine a set of empirical shuffling rules for working out an automated fuel loading pattern search code, ALPS. The numerical examples are presented for verifying effectiveness and applicability of individual codes. By structuring and applying three codes for reload core design problem of a PWR, it is demonstrated that these codes provide an effective in-core fuel management scoping tool for PWR.

• Journal of Environmental Science International
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• v.1 no.1
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• pp.19-33
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• 1992

The high oxidants, which occur the daily maximum concentrations in the afternoon, are transported into the other region via long range transport mechanisms or trapped within the shallow mixing boundary layer and then removed physically (deposition, transport by mountain wind, etc.) and chemically (reaction with local sources). Therefore, modeling formation of photochemical oxidants requires a complex description of both chemical and meteorolog ital processecs . In this study, as a part of air quality studies, we reviewed various aspects of photochemical modeling on the basis of currently available literature. The result of the review shows that the model is based on a set of coupled continuity equations describing advection, diffusion, transport, deposition, chemistry, emission. Also photochemical oxidant models require a large amount of input data concerned with all aspects of the ozone life cycle. First, emission inventories of hydrocarbon and nitrogen oxides, with appropriate spatial and temporal resolution. Second, chemical and photochemical data allowing the quantitative description of the formation of ozone and other photochemically-generated secondary pollutants. Third, dry deposition mechanisms particularly for ozone, PAN and hydrogen peroxide to account for their removal by absorption on the ground, crops, natural vegetation, man-made and water surfaces. Finally, meteorological data describing the transport of primary pollutants away from their sources and of secondary pollutants towards the sensitive receptors where environmental damage may occur. In order to improve our present study, shortcomings and limitation of existing models are pointed out and verification Process through observation is emphasized.

• Journal of Korean Port Research
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• v.14 no.4
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• pp.429-439
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• 2000

The primary purpose of dredging work is to maintain navigational readiness and to increase environmental amenity. Therefore the dredging project, which is composed of excavating, removing, transporting and storing or dumping dredged material, must be carefully managed to insure that dredging works are completed in a cost-effective and environmentally safe method. The most important point in dumping operations is evaluating and decreasing the impacts of dumping works at the dumping area. One of the most effective method for this purpose is using the schematic process composed of the sophisticate plan, precise work and predicting/reducing the impacts based on an numerical model being closely linked with field observation. In this study, a numerical model is used to predict the spatial transport and fate of the effluent discharged from the confined dumping facility(CDF) located at a coastal area. To achive this purpose, numerical models were used for reappearing the tidal current of concerned area. These models were then applied to Mokpo harbpr where capital dredging and maintenance dredging are being conducted simultaneously and the CDF is under construction. In series of model case study, we found that the effluent discharged from CDF was governed by the receiving water condition and outfall geometry, so that limit of near-field was 14∼500 meter down stream and 4∼150 meter in transverse direction. dilution ranged from 1.1 to 8.2 on the cases. Long-term diffusion characteristics was governed by the dilution rate during near-field behavior, ambient conditions and CDF operation modes.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.26-31
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• 2014

In this paper, we present performance analysis of video smoke detection based on BPN-Network that is using multi-smoke feature, and Neural Network. Conventional smoke detection method consist of simple or mixed functions using color, temporal, spatial characteristics. However, most of all, they don't consider the early fire conditions. In this paper, we analysis the smoke color and motion characteristics, and revised distinguish the candidate smoke region. Smoke diffusion, transparency and shape features are used for detection stage. Then it apply the BPN-Network (Back-Propagation Neural Network). The simulation results showed 91.31% accuracy and 2.62% of false detection rate.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2006.05a
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• pp.298-301
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• 2006

This paper describes the electron energy distribution function characteristics in $SF_6-Ar$ gas calculated for range of E/N values from $50\sim700[Td]$ by the Monte Carlo simulation(MCS) and Boltzmann equation(BE) method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained by time of flight(TOF) method. In this dissertation the results of the combined experimental and theoretical studies designed to understand and predict the spatial growth and transport coefficients for electrons in $SF_6$ and $SF_6-Ar$ mixtures have described. The ionization and attachment coefficients in pure $SF_6$ and $SF_6-Ar$ mixtures have been calculated over the range of 10$SF_6$ molecule and for Ar atom proposed by other authors. The results obtained in this work will provide valuable information on the fundamental behaviors of electrons in weakly ionized gases and the role of electron attachment in the choice of better gases and unitary gas dielectrics or electro negative components in dielectric gas mixtures.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1157-1164
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• 2017

The Monte Carlo criticality simulation of decoupled systems, as for instance in large reactor cores, has been a challenging issue for a long time. In particular, due to limited computer time resources, the number of neutrons simulated per generation is still many order of magnitudes below realistic statistics, even during the start-up phases of reactors. This limited number of neutrons triggers a strong clustering effect of the neutron population that affects Monte Carlo tallies. Below a certain threshold, not only is the variance affected but also the estimation of the eigenvectors. In this paper we will build a time-dependent diffusion equation that takes into account both spatial correlations and population control (fixed number of neutrons along generations). We will show that its solution obeys a traveling wave dynamic, and we will discuss the mechanism that explains this biasing of local tallies whenever leakage boundary conditions are applied to the system.