• Journal of the Institute of Electronics Engineers of Korea SP
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• v.38 no.1
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• pp.1-10
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• 2001

In order to generate the gray scale image by the binary state imaging devices such as a digital printer, the gray scale image needs to be converted into the binary image by the halftoning techniques. This paper presents a new error diffusion technique to achieve the homogeneous dot distributions on the binary images. In this paper,'the minimum pixel distance'from the current pixel under binarization to the nearest minor pixel is defined first. Also, the gray levels of the input image are converted into a new variable based on the principal distance for the error diffusion. In the proposed method, the difference in the principal distances is utilized for the error propagation, whereas the gray level difference due to the binarization is diffused to the neighboring pixels in the existing error diffusion techniques. The quantization is accomplished by comparing the updated principal distance with the minimum pixel distance. In order to calculate the minimum pixel distance, MPOA(Minor Pixel Offset Array) is employed to reduce the computational loads and memory resources.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1938-1962
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• 2015

Security of information during transmission is a major issue in this modern era. All of the communicating bodies want confidentiality, integrity, and authenticity of their secret information. Researchers have presented various schemes to cope with these Internet security issues. In this context, both steganography and cryptography can be used effectively. However, major limitation in the existing steganographic methods is the low-quality output stego images, which consequently results in the lack of security. To cope with these issues, we present an efficient method for RGB images based on gray level modification (GLM) and multi-level encryption (MLE). The secret key and secret data is encrypted using MLE algorithm before mapping it to the grey-levels of the cover image. Then, a transposition function is applied on cover image prior to data hiding. The usage of transpose, secret key, MLE, and GLM adds four different levels of security to the proposed algorithm, making it very difficult for a malicious user to extract the original secret information. The proposed method is evaluated both quantitatively and qualitatively. The experimental results, compared with several state-of-the-art algorithms, show that the proposed algorithm not only enhances the quality of stego images but also provides multiple levels of security, which can significantly misguide image steganalysis and makes the attack on this algorithm more challenging.

• Journal of Biomedical Engineering Research
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• v.15 no.2
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• pp.129-134
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• 1994

In this paper, computerized BEAM was implemented for the space domain analysis of EEG. Transformation from temporal summation to two-dimensional mappings is formed by 4 nearest point interpolaton method. Methods of representation of BEAM are two. One is dot density method which classify brain electrical potential 9 levels by dot density of gray levels and the other is colour method which classify brain electrical 12 levels by red-green colours. In this BEAM, instantaneous change and average energy distribution over any arbitrary time interval of brain electrical activity could be observed and analyzed easily. In the frequency domain, the distribution of energy spectrum of a special band can easily be distinguished normality and abnormality.

• Investigative Magnetic Resonance Imaging
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• v.17 no.2
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• pp.123-132
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• 2013

Purpose : We report the results of the various parameters of diffusion tensor imaging (DTI) and CSF flow study of the cervical spinal cord using magnetic resonance (MR) imaging techniques. Materials and Methods: Intramedullary FA and MD were measured in the gray matter and posterior cord of the white matter and both lateral cords of the white matter at the C2-3, C4-5, C5-6 spinal levels. For the CSF flow study, velocity encoding was obtained at the C2-3, C4-5, C5-6 spinal levels. Results: There was a significant difference of the FA and MD between the white matter and gray matter (p < 0.05). The FA of the gray matter was significantly different according to the cervical spinal cord levels (p < 0.05). Otherwise, the FA and MD parameters were not significantly different (p > 0.05). The mean peak systolic velocity and mean peak diastolic velocity were $5.18{\pm}2.00cm/sec$ and $-7.32{\pm}3.18cm/sec$, respectively from C2 to C6 spinal cords. There was no significant difference in these velocities among the cervical spinal cord (p > 0.05). Conclusion: This basic information about DTI and CSF dynamics of the cervical spinal cord may be useful for assessing cervical spinal cord abnormalities using MR imaging.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.4
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• pp.435-441
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• 1998

We examined effects of interleukin $1{\alpha}$ ($IL1{\alpha}$) and phorbol 12, 13 dibutyrate (PDB), an activator of protein kinase C, on mRNA for Prostaglandin H synthase (PGHS) and prostanoid production in cultured ovine meningeal fibroblasts. Immuno- and morphologically-identified fibroblasts were derived from cerebral cortex and white matter from fetal lambs (approximately 120 days gestation) and grown to confluence on glass coverslips in 12 well plates. Levels of prostaglandin $F_{2{\alpha}}$ and the stable hydrolysis product of prostacyclin (i.e., $6-keto-PGF_{1{\alpha}}$) were determined using enzyme immunoassay. Relative amounts of mRNA were determined by in situ hybridization using ovine cDNA for PGHS1. $IL1{\alpha}$ (10 ng/ml) increased mRNA levels over baseline by $62{\pm}19%$ (p＜0.05) at 60 min., $37{\pm}12%$ (NS) at 120 min., and $36{\pm}18%$ (NS) at 240 min (n=12). Levels of $6-keto-PGF_{1{\alpha}}$ were $148{\pm}18%$ pg/ml during baseline, $246{\pm}41%$ pg/ml at 60 min., $248{\pm}40%$ pg/ml at 120 min., and $259{\pm}62%$ pg/ml at 240 min (all p＜0.05) (n=12). $PGF_{2{\alpha}}$ was increased although it wasn't statistically significant. However, $IL1{\alpha}$ decreased $PGE_2$ level significantly (all p＜0.05). PDB $(10^{-6}M)$ increased mRNA levels over baseline by $25{\pm}6%$ after 30 min., $40{\pm}6%$ after 60 min., and $20{\pm}8%$ after 90 min. (n=9) (all p＜0.05). Levels of $6-keto-PGF_{1{\alpha}}$ were $200{\pm}43%$ pg/ml during baseline, $202{\pm}43%$ pg/ml after 30 min. (NS), $268{\pm}58%$ pg/ml after 60 min. (p＜0.05), and $296{\pm}60%$ pg/ml after 90 min. (p＜0.05) (n=9). Levels of $PGF_{2{\alpha}}$ were $178{\pm}26%$ pg/ml during baseline, $300{\pm}30%$ pg/ml after 30 min., $299{\pm}35%$ pg/ml after 60 min., and $355{\pm}32%$ pg/ml after 90 min (all p＜0.05) (n=6). Actinomycin-D (1 mg/ml) prevented increases in mRNA, $6-keto-PGF_{1{\alpha}}$, and $PGF_{2{\alpha}}$ at 60 min. for both $IL1{\alpha}$ and PDB. We conclude that cerebral fibroblasts are avid producers of prostanoids, and that enhanced production of PGHS is responsible for augmented $PGF_{2{\alpha}}$ and prostacyclin production in the presence of an activator of protein kinase C and for decreased $PGE_2$ and increased prostacyclin production in the presence of $IL1{\alpha}$.

• Journal of Information Display
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• v.7 no.1
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• pp.30-34
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• 2006

A sub-field rearrangement driving method has been proposed to reduce a DFC (Dynamic False Contour) phenomenon in plasma display panels. The proposed driving method expresses 256 gray levels with 16 sub-fields, while conventional one uses only 8 sub-fields. Notwithstanding the increase in the number of sub-fields, the display time is similar to the conventional 8 sub-fields driving method by appropriate choosing selective writing and selective erasing for sub-fields.

• Journal of the Optical Society of Korea
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• v.15 no.2
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• pp.168-173
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• 2011

Based on the distinctive characteristics observed in the intensity transmittance of an IPS-LC panel, the previous one-dimensional model is greatly reduced such that only a few data points and their interpolations predict the intensity transmittance of an IPS-LCD with a small error for arbitrary gray levels. Experimental procedure and numerical methods are described in detail.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.6
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• pp.725-730
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• 2007

Gray-level histogram-based threshold selection methods such as Otsu's method, Huang and Wang's method, and etc. have been widely used for the threshold selection in image processing. They are simple and effective, but take too much time to determine the optimal multilevel threshold values as the number of thresholds are increased. In this paper, we measure correlation between gray-levels by using the Gaussian function and define a Gaussian-type finite mixture distribution which is combination of the Gaussian distribution function with the gray-level histogram, and propose a fast and effective threshold selection method using it. We show the effectiveness of the proposed through experimental results applied it to three images and the efficiency though comparison of the computational complexity of the proposed with that of Otsu's method.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.2
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• pp.153-159
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• 2017

We examined changes in the physiological responses of gray mullet Mugil cephalus exposed to acidic seawater (pH 6.0, 6.5, 7.0) and normal seawater (pH 8.0, control) for 15 days. As pH decreased, survival rate and body weight also decreased. Levels of aminotransferase, total protein and triglycerides also differed significantly with changes in pH, presumably due to stress caused by exposure to acidic water. The level of osmotic pressure was significantly higher in the pH 6.0 group than in other groups. Superoxide dismutase was significantly higher in the pH 6.5 and 7.0 groups than in the pH 8.0 group, and glutathione level was lowest in the pH 6.0 group. We conclude that decreasing the pH level of seawater induces a stress response in fish, damaging their ability to control their hematological and osmotic pressure. Antioxidant enzymes are generally sensitive to osmotic stress; in this study, antioxidant activity significantly changed with pH level. These results indicate that physiological stress induced by exposure to acidification reduces survival rates and inhibits growth in M. cephalus.

• Korean Journal of Medicinal Crop Science
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• v.22 no.6
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• pp.483-488
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• 2014

Lime-bordeaux mixture (LBM) has been used instead of pesticides in ginseng field and orchard since the 1960's in Korea. In this experiment, LBM was made with different concentrations and sprayed in the field of ginseng for eco-friendly cultivation. Growth characteristics and disease such as alternaria blight, anthracnose, and gray mold were investigated in 4-5 year old ginseng after spraying LBM. LBM caused a little damage on leaf when it was sprayed at the time of leafing stage, late April and early May. Root weights of five-year-old ginseng were 43.1~51.5 g and 41.2~46.6 g in the plot of mid-April and mid-May treatments, respectively. These growth levels were further reduced as compared with that of the chemicals treatment plot. The rate of diseases in the plot of 6-6 and 8-8 ratio were 0.0~4.8% and 0.0~4.4%, respectively, which was similar with that in the plot of chemical control for alternaria blight and anthracnose. However, LBM had little effect on controling gray mold. It showed lower control effect in the plot of 4-4 ratio than that of chemical control. This result will be expected to be a useful guide that can be used in the field to the farmers of the ginseng.