• International Journal of Internet, Broadcasting and Communication
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• 제13권1호
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• pp.187-193
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• 2021

In this paper, we propose an image watermarking technique that effectively hides confidential data in the LSB of image pixels by utilizing the characteristics of the image. In the proposed technique, the image is precisely divided into boundary surface and normal region other than the boundary surface and performs different processing. The boundary surface existing in the image is created by meeting different regions and contains important information of the image. One bit of confidential data is concealed in the LSB of the pixel at the boundary surface to preserve the characteristics of the boundary surface. In normal region other than the boundary surface, the pixel values are similar, and the change with the adjacent pixel values is smooth. Based on this property, even if the 2 bits of confidential data are hidden in the lower 2 bits of the pixel in the normal region, the difference cannot be visually distinguished. When confidential data is concealed in an image as described above, the amount of confidential data concealed in an image can be increased while maintaining excellent image quality. Concealing confidential data by applying the proposed method increases the amount of confidential data concealed by up to 84.6% compared to the existing method. The proposed technique can be effectively used for commercial image watermarking that hides copyright information.

• 품질경영학회지
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• 제49권1호
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• pp.31-45
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• 2021

Purpose: A noncentral composite design method is to be developed to explore farther region for the first factorial design. A general guideline for sequential experimentation is provided. Methods: (1) A non-overlapping noncentral composite design (NNCD) is developed, in which the second factorial design shares one design point that indicates the best response value in the first factorial design. (2) Four composite designs are compared in terms of the four design evaluation criteria, which are D-, A, G, and I-optimality. (3) A follow-up design strategy is suggested based on the interaction effect, direction of improvement, number of factors. Results: (1) NNCD and model building method are presented, which is useful for exploring farther region from first factorial design block. (2) The performances of the four composite designs are compared. (3) A follow-up design strategy is suggested. Conclusion: (1) NNCD will be useful to explore farther region for the first factorial design. (2) A follow-up design strategy can be beneficial to the experimental practitioners for product and process design and improvement.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.488-495
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• 2000

Strain SA72 was isolated from Jeot-gal and identified as producer of a bacteriocin, which showed some bactericidal activity against Lactobacillus delbrueckii ATCC 4797. Strain SA72 was tentatively identified as Lactococcus lactis according to the AOI test. Lactococcus lactis SA72 showed a broad spectrum of microorganisms, tested by the modified deferred method. The activity of lacticion SA72, named tentatively as a bacteriocin produced by Lactococcus lactis SA72, was detected during the mid-lon growth phase, reached a maximum during the early stationary phase, and then declined after the late stationary phase. Lacticin SA72 also showed a relatively broad spectrum of activity against non-pathogenic and pathogenic microorganisms when assessed by the spot-on-lawn method. Its anitimicrobial activity on sensitive indicator cells disappeared completely by protease XIV treatment. The inhibitory activity of lacticin SA72 remained after treatment for 15 min at $121^{\circ}C$, 문 was stable in a pH range of 2.0 to 9.0 and all organic solvents examined. It demonstrated a typical bactericidal mode of inhibition against Lactobacillus delbrueckii ATCC 4797. The apparent molecular mass of lacticin SA72 was in the region of 3-3.5 kDa, determined by SDS-PAGE.

• 한국연소학회지
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• 제20권1호
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• pp.24-31
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• 2015

Flame structure, which contains a useful information for studying combustion instability of the flame, is often quantitatively visualized with PLIF (planar laser-induced fluorescence) and/or chemiluminescence images. The latter, a line-integral of a flame property, needs to be preprocessed before being inverted, mainly due to its inherent noise and the axisymmetry assumption of the inversion. A preprocessing scheme utilizing multi-division of ROI (region of interest) of the chemiluminescence image is proposed. Its feasibility has been tested with OH PLIF and $OH^*$ chemiluminescence images of SNG (synthetic natural gas) swirl-stabilized flames taken from a model gas turbine combustor. It turns out that the multi-division technique outperforms two conventional ones: those are, one without preprocessing and the other with uni-division preprocessing, reconstructing the SNG flame structure much better than its two counterparts, when compared with the corresponding OH PLIF images. It is also found that the Canny edge detection algorithm used for detecting edges in the multi-division method works better than the Sobel algorithm does.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1511-1514
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• 2002

This paper presents content adaptive image watermark embedding using stochastic visual model based on multiwavelet transform. To embedding watermark, the original image is decomposed into 4 levels using a discrete multiwavelet transform, then a watermark is embedded into the JND(just noticeable differences) of the image each subband. The perceptual model is applied with a stochastic approach fer watermark embedding. This is based on the computation of a NVF(noise visibility function) that have local image properties. The perceptual model with content adaptive watermarking algorithm embed at the texture and edge region for more strongly embedded watermark by the JND. This method uses stationary Generalized Gaussian model characteristic because watermark has noise properties. The experiment results of simulation of the proposed watermark embedding method using stochastic visual model based on multiwavelet transform techniques was found to be excellent invisibility and robustness.

• 한국컴퓨터정보학회논문지
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• 제23권9호
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• pp.1-6
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• 2018

In this paper, we propose a method dividing effectively the hand and fingers using general webcam. The method executes 4 times empirically preprocessing one to erase noise. First, it erases the overall noise of the image using Gaussian smoothing. Second, it changes from RGB image to HSV color model and YCbCr color model, executes a global static binarization based on the statistical value for each color model, and erase the noise through bitwise-OR operation. Third, it executes outline approximation and inner region filling algorithm using RDP algorithm and Flood fill algorithm and erase noise. Lastly, it erases noise through morphological operation and determines the threshold propositional to the image size and selects the hand and fingers area. This paper compares to existing one color based hand area division method and focuses the noise deduction and can be used to a gesture recognition application.

• 한국주조공학회지
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• 제24권1호
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• pp.40-44
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• 2004

The influence of Pd and Ag additions on the thermal stability, the glass forming ability (GFA) and mechanical property of $Zr_{55}Al_{10}Cu_{20}Ni_{10}Pb_{(5-x)}Ag_x$ (x = $0{\sim}5at%$) alloys obtained by melt spun and injection casting method have been investigated by using of X-ray diffraction, thermal analysis (DTA, DSC) and micro-Vickers hardness(Hv) testing. The thermal properties of melt-spun $Zr_{55}Al_{10}Cu_{20}Ni_{10}Pb_{(5-x)}Ag_x$ (x = $0{\sim}5at%$) alloys exhibit a supercooled liquid region(${\Delta}T_x$) exceeding 91 K before crystallization. The largest ${\Delta}T_x$ reaches as large as 126 K for the $Zr_{55}Al_{10}Cu_{20}Ni_{10}Pb_5$ alloy. The reduced glass transition temperature, $T_{rg}$ increased with increasing Ag content. The largest $T_{rg}$ is obtained for the $Zr_{55}Al_{10}Cu_{10}Ni_{10}Ag_5$ alloy. The $Zr_{55}Al_{10}Cu_{10}Ni_{10}Ag_5$ bulk amorphous alloy rod with 3 mm in diameter was fabricated by injection casting. Hv increased with increasing Ag content and the largest value was obtained for the $Zr_{55}Al_{10}Cu_{10}Ni_{10}Ag_5$ bulk amorphous alloy.

• Bulletin of the Korean Chemical Society
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• 제33권11호
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• pp.3767-3771
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• 2012

In this study, we investigate the potential use of $TiO_2@SiO_2$ and $ZnO@SiO_2$ core/shell nanoparticles (NPs) as effective UV shielding agent. In the typical synthesis, $SiO_2$ was coated over different types of $TiO_2$ (anatase and rutile) and ZnO by sol-gel method. The synthesized $TiO_2@SiO_2$ and $ZnO@SiO_2$ NPs were characterized by UV-Vis, XRD, SEM and TEM. The UV-vis absorbance and transmittance spectra of core@shell NPs showed an efficient blocking effect in the UV region and more than 90% transmittance in the visible region. XRD and SAED studies confirmed the formation of amorphous $SiO_2$ coated over the $TiO_2$ and ZnO NPs. The FESEM and TEM images shows that coating of $SiO_2$ over the surface of anatase, rutile $TiO_2$ and ZnO NPs resulted in the increase in particle size by ~30 nm. In order to study the UV light shielding capability of the samples, photocatalytic degradation of methylene blue dye on $TiO_2@SiO_2$ and $ZnO@SiO_2$ NPs was performed. Photocatalytic activity for both types of $TiO_2$ NPs was partially suppressed. In comparison, the photocatalytic activity of ZnO almost vanished after the $SiO_2$ coating.

• 한국물환경학회지
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• 제23권4호
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• pp.561-567
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• 2007

It is necessary to predict future water pollution sources in the establishment of Total Maximum Daily Load (TMDL) plan for watershed management. There are some difficulties and limits in estimating the pollution sources accurately since the prediction method is not firmly established. This study reviewed the existing methods of prediction and developed a technique characteristics. The characteristics were obtained by analyzing the change pattern of pollution sources by region and incorporated in the technique. A distinctive feature of the technique is to eliminate the influences of land use change included in the pollution source data of a region. The technique has been applied and tested. The test result showed the improvement on the prediction accuracy. A computer program was also developed for the easy application of the technique.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.114-120
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• 2014

In this paper, a method for multi-physics analysis of the temperature-dependent properties of an oil-immersed transformer is discussed. To couple thermal fields with electromagnetic and fluid fields, an algorithm employing a user defined function (UDF) is proposed. Using electromagnetic analysis, electric power loss dependent on temperature rise is calculated; these are used as input data for multi-physics analysis in order to predict the temperature rise. A heat transfer coefficient is applied only at the outermost boundary between transformer and the atmosphere in order to reduce the analysis region. To verify the validity of the proposed method, the predicted temperature rises in high-voltage (HV) and low-voltage (LV) windings and radiators were compared with the experimental values.