• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.5
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• pp.1055-1063
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• 2012

The noise of image is added by many environmental factors. Therefore, we need to remove these noises using the conventional filtering methods, which are optimized based on the statistical characteristic of noise. In direct restoration method, there is an inverse filter and the wiener filter. Here, the wiener filter is the optimized filter in the view of least square method. First, we are going to study the inverse filter, wiener filter, constraint least square filter. Second, in order to control the quantity, we use the parameters instead of the power spectrum ratio. But, these parameters have the conflicting condition, therefore, we optimized the variables using parametric wiener filter which adjust the application appropriately. In the simulation results, the contrast of the degraded image was enhanced and the noise was removed. Comparative experimentation was demonstrated edge preserving and noise removing property.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.8B
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• pp.1549-1557
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• 1999

In this paper, we propose a face recognition algorithm based on the differential image method-DCT This algorithm uses neural networks which is flexible for noise. Using the same condition (same luminous intensity and same distance from the fixed CCD camera to human face), we have captured two images. One doesn't contain human face. The other contains human face. Differential image method is used to separate the second image into face region and background region. After that, we have extracted square area from the face region, which is based on the edge distribution. This square region is used as the characteristics region of human face. It contains the eye bows, the eyes, the nose, and the mouth. After executing DCT for this square region, we have extracted the feature vectors. The feature vectors were normalized and used as the input vectors of the neural network. Simulation results show 100% recognition rate when face images were learned and 92.25% recognition rate when face images weren't learned for 30 persons.

• Smart Media Journal
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• v.6 no.3
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• pp.15-20
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• 2017

Recently, the automotive industry has been studied about driver assistance systems for helping drivers to drive their cars easily by integrating them with the IT technology. This study suggests a method of detecting lanes, robust to road condition changes and applicable to lane departure warning and autonomous vehicles mode. The proposed method uses the method of detecting candidate areas by using the Gaussian filter and by determining the Otsu threshold value and edge. Moreover, the proposed method uses lane gradient and width information through the Hough transform to detect lanes. The method uses road lane information detected before to detect dashed lines as well as solid lines, calculates routes in which the lanes will be located in the next frame to draw virtual lanes. The proposed algorithm was identified to be able to detect lanes in both dashed- and solid-line situations, and implement real-time processing where applied to Raspberry Pi 2 which is open source hardware.

• Nuclear Engineering and Technology
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• v.48 no.6
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• pp.1330-1337
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• 2016

A visualization test of the fuel-coolant interaction in the Test for Real cOrium Interaction with water (TROI) test facility was carried out. To experimentally simulate the In-Vessel corium Retention (IVR)- External Reactor Vessel Cooling (ERVC) conditions, prototypic corium was released directly into the coolant water without a free fall in a gas phase before making contact with the coolant. Corium (34.39 kg) consisting of uranium oxide and zirconium oxide with a weight ratio of 8:2 was superheated, and 22.54 kg of the 34.39 kg corium was passed through water contained in a transparent interaction vessel. An image of the corium jet behavior in the coolant was taken by a high-speed camera every millisecond. Thermocouple junctions installed in the vertical direction of the coolant were cut sequentially by the falling corium jet. It was clearly observed that the visualization image of the corium jet taken during the fuel-coolant interaction corresponded with the temperature variations in the direction of the falling melt. The corium penetrated through the coolant, and the jet leading edge velocity was 2.0 m/s. Debris smaller than 1 mm was 15% of the total weight of the debris collected after a fuel-coolant interaction test, and the mass median diameter was 2.9 mm.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.5
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• pp.952-958
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• 1988

To analyze the nonflatness and residual stress in accelerated cooled plate, a numerical analysis model has been developed. Two factors, i.e. temperature and phase transformation, are considered in calculating the stress distribution that develops during cooling. The plastic strain and plate-buckling, which are often shown in accelerated cooled plate, were determined from this stress. Mean temperature in through thickness direction and temperature difference in width direction are considered in the model to simplify the calculation. The temperature and stress distribution changes caused by phase transformation are involved in terms of the effective specific heat and the effective thermal expansion coefficient. With the model, accelerated cooling of 10mm(t) $^{*}$3000mm(w) plate was simulated. The condition of accelerated cooling was .deg. C/sec from just after hot rolling to 500.deg. C. The initial temperature-difference ratio, .DELTA.Tr, in width direction is an important factor in evaluating the stress distribution. When .DELTA.Tr is 0.08, buckling occurs during cooling and 7kgf/m $m^{2}$ of residual stress develops at the edge of plate. To secure the flatness, .DELTA.Tr should be less than 0.07. Small scaled cooling test was conducted to verify the exactness of the model and the results proved the usefulness of this numerical analysis model.l.

• Economic and Environmental Geology
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• v.37 no.3
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• pp.291-301
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• 2004

In order to charaterize weathering of chalcopyrite and behavior of dissolved metal ions in waste rocks from Manjang Cu mine, mineralogical studies such as refractive microscope, XRD and SEM/EDS analyses carried out. The weathering was mainly occurred in fractures and edge of the chalcopyrite within the mine waste rocks. The weathering process can be seen to reflect four stages based on the weathering degree of chalcopyrite. The main secondary minerals are goethite, covellite, azurite, malachite and brochantite. Dissolved Cu and As were mainly adsorbed Fe-hydroxide. Poorly crystalline Fe-oxide contains relatively high As contents. In oxdizing condition, the weathering of chalcopyrite mainly occurs along the fracture, while the replacement of chalcopyrite observed mainly in the grain and produced covellite and brochantite. The dissolved metals (Cu, Fe, As) in waste rocks from the abandoned Manjang mine area could attenuate naturally by precipitation, adsorption and replacement reaction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.156-164
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• 2010

A total of 6 stepwise constructions were made for building the floating mass concrete foundation. The optimal curing strategies and specialized construction guidelines were adoptively extracted from the 1.5m cube mock-up test prior to the main concrete work. Two different thermal crack index(TCI) calculations from current construction manual exhibit relatively low values as comparing the measured temperature data. This implies that the hydration-induced cracking could be developed in parts of concrete mass. However, the controversial phenomenons in reality were observed. No significant surface cracks are detected at the successive construction stages. Thereby, this paper raises the question regarding on the existence of characteristic length with varying size and shape of a target specimen which are missing in the current construction manual. The isothermal core area and high thermal gradient area in the edge volume should be identified and be introduced to TCI calculation for the purpose of an accuracy.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.233-233
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• 2010

CdS thin films were deposited on glass substrates by R.F. magnetron sputtering method and some of the samples were treated by rapid thermal annealing (RTA) process. Effects of thermal annealing on structural and optical properties were investigated at different temperatures ranging from 100 to $600^{\circ}C$. The crystallographic structure of the films and the size of the crystallites in the films were studied by X-ray diffraction. The crystallite sizes were found to increase, and the X-ray diffraction patterns were seen to sharpen by annealing. Optical properties of the films were calculated using the envelope method and the photoluminescence measurements. The optical properties of the films were seen to be dependent on the film thicknesses. The energy gap of the films was found to decrease by annealing. The band edge sharpness of the optical absorption was seen to oscillate by thermal annealing. Annealing over $400^{\circ}C$ was seen to degrade the optical properties of the film. The best annealing temperature for the films was found to be $400^{\circ}C$ from the optical properties. It is observed that the CdS film annealed at $400^{\circ}C$ reveals the strongest UV emission intensity and narrowest full width at half maximum among the temperature ranges studied. The enhanced UV emission from the film annealed at $400^{\circ}C$ is attributed to the improved crystalline quality of CdS thin film due to the effective relaxation of residual compressive stress and achieving maximum grain size. The results show that heat treatments under optimal annealing condition can provide significant improvements in the properties of CdS thin films.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.5
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• pp.587-594
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• 2019

This study experimentally investigated the effects of high and low densities of vegetation patches on the flow characteristics in a stream-scale outdoor experimental channel with rooted willows. Stream-scale experiments on vegetated flows were carried out for an emergent condition of vegetation. Vegetation patches were arranged by alternate bar formation and the flows in vegetated and non-vegetated sections were compared. Three-dimensional flow structure was measured by ADV (Acoustic Doppler Velocimeter) and the vertical distributions of longitudinal velocity were mainly analyzed from the measurements at various points. Flow velocities show different patterns depending on the density of vegetation patches. The difference in flow velocity between in the vegetated and non-vegetated sections appear to large in the dense patches and the flow becomes complicated at the downstream edge of the patch. Despite the upstream flow disturbed by the first patch, the flows over the second patch show the similar pattern.

• Journal of the Society of Naval Architects of Korea
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• v.31 no.4
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• pp.130-138
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• 1994

Bottom plates of empty hold are subjected to not only water pressure but also bi-axial inplane loads, specially in the alternate full loading full loading condition of bulk carrier. This kind of plate behaviours is very difficult to be explained and to be estimated using common buckling design guide in the initial design stage of hull structure, therefore, some more concrete studies for this plate structure was performed based on the currently developed buckling estimation formula. In this buckling formula, torsional stiffness effects of edge stiffener are included additionally and effects of elastic buckling strength of plate panel are treated as characteristic value problem. Also considering boundary stiffener effects and inplane and lateral loading, evaluation of bottom plate scantling using this formula, calculated results using various classification regulation of buckling strength and results of first report approach are compared each other and useful guides using developed formula for bottom plate scantling design are discussed.