• Journal of the Korean Institute of Telematics and Electronics S
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• 제35S권4호
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• pp.85-95
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• 1998

In this paper, a new watermarking method for a copy protectionof images is proposed. The proposed method adaptively embeds a watermark in the frequency domain of images using human visual system model. For this purpose, the Just Noticeable Differences(JNDs) of each frequency coeffeicient value of a luminance plane is first found using Watson and Solomon's visual system model. An invisible maximum watermark value with is different in every position according to the characteristics of images is determined usig JND and Minkowski metric. A low frequency domain is divided into two sets based on a PN-sequence to protect thewatermark from the attack. The watermarks are added to one set of coefficients and detecting a watermark, the difference between the mean values of absolute coefficient values of both sets is calculated. The embedded watermark is tested using statistical hypothesis based on test static dertermined by the ean difference. To demonstrate the perfromance of the proposed method, the new watermarking method is applied to a high frequency image and low frequency images. Experimenatal results show the watermark is invisible and robust to JPEGlossy compression and noise.

• Korean Journal of Plant Resources
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• 제20권6호
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• pp.544-547
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• 2007

The effects of hwangryun(Coptidis Rhizoma) on lowering lipid and oxidative stress in the induced obesity rat was observed. The concentration of plasma triglyceride in hwangryun treatment groups showed the low values compared to the control group, and as the increased hwangryun, the concentration of triglyceride decreased. The concentration of plasma total cholesterol decreased in all hwangryun treatment groups. However the concentration of plasma HDL-cholesterol and LDL-cholesterol showed no significantly difference in all the treatment groups. Thiobarbituric acid reactive substance(TBARS) concentration in plasma and liver showed low values in all hwangryun treatment groups compared to the control group. Glutathione peroxidase(GSH-Px) and superoxide dismutase(SOD) activities showed no significantly difference in all the treatment groups. However catalase(CAT) activity showed a tendence to increase in hwangryun groups, and in 200mg/kg hwangryun treatment group showed significantly a high value than the control group. Summarizing the results above, hwangryun has the functional materials that lowering lipid and works with oxidative stress.

• Journal of Korean Vacuum Science & Technology
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• 제2권1호
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• pp.13-19
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• 1998

We have calculated the electronic structure of impurity atoms in metal host by using the tight binding model in the recursion method. For a self-consistent calculation, we assumed that the effect of impurity introduction was localized only at the impurity site and its neighbours. We calculated the Madelung term by limiting the contribution to Vm of the charge perturbations to the first shell around the impurity with Evjen technique. The calculated local density of states and charge transfer values have been compared with the experimental values for a single impurity in metal host. We fund that d-reso-nance state came from the repulsive interaction between impurity d-state and host band, and the position of d-resonance state depended on the difference of valence electrons between the host and the impurity. the results also showed that the charge transfer value between an impurity and host metal was comparable to the ionicity difference between them.

• Food Science and Biotechnology
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• 제14권3호
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• pp.328-333
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• 2005

Finite difference model and dynamic thermal property evaluation system were developed to estimate convection heat transfer coefficient by modeling temperature-time profile of beef cube in continuous flow sterilizing system. As input parameters of the model, specific heat and thermal conductivity values of beef frankfurter meat were independently measured from 20 to $80^{\circ}C$. Convection heat transfer coefficient was estimated by comparing simulated and measured temperature-time profiles. Actual temperature-time profiles of meat cube were measured at flow rates of 15, 30, and 45 L/min and viscosities from 0 to 15 cp, and mean values of convection heat transfer coefficients ranged from 792 to $2107\;W/m^2{\cdot}K$. Convection heat transfer coefficient increased with increase in flow rate and decreased as viscosity increased.

• International Journal of Computer Science & Network Security
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• 제21권12호
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• pp.223-227
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• 2021

A treatment based on the algebraic operations on fuzzy numbers is used to replace the fuzzy problem into an equivalent crisp one. The finite difference technique is used to replace the continuous boundary value problem (BVP) of arbitrary order 1<α≤2, with fuzzy boundary parameters into an equivalent crisp (algebraic or differential) system. Three numerical examples with different behaviors are considered to illustrate the treatment of the singular perturbed case with different fractional orders of the BVP (α=1.8, α=1.9) as well as the classical second order (α=2). The calculated fuzzy solutions are compared with the crisp solutions of the singular perturbed BVP using triangular membership function (r-cut representation in parametric form) for different values of the singular perturbed parameter (ε=0.8, ε=0.9, ε=1.0). Results are illustrated graphically for the different values of the included parameters.

• Nuclear Engineering and Technology
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• 제49권7호
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• pp.1495-1504
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• 2017

In a previous study, a set of polygon-mesh (PM)-based skin models including a $50-{\mu}m-thick$ radiosensitive target layer were constructed and used to calculate skin dose coefficients (DCs) for idealized external beams of electrons. The results showed that the calculated skin DCs were significantly different from the International Commission on Radiological Protection (ICRP) Publication 116 skin DCs calculated using voxel-type ICRP reference phantoms that do not include the thin target layer. The difference was as large as 7,700 times for electron energies less than 1 MeV, which raises a significant issue that should be addressed subsequently. In the present study, therefore, as an extension of the initial, previous study, skin DCs for three other particles (photons, protons, and helium ions) were calculated by using the PM-based skin models and the calculated values were compared with the ICRP-116 skin DCs. The analysis of our results showed that for the photon exposures, the calculated values were generally in good agreement with the ICRP-116 values. For the charged particles, by contrast, there was a significant difference between the PM-model-calculated skin DCs and the ICRP-116 values. Specifically, the ICRP-116 skin DCs were smaller than those calculated by the PM models-which is to say that they were under-estimated-by up to ~16 times for both protons and helium ions. These differences in skin dose also significantly affected the calculation of the effective dose (E) values, which is reasonable, considering that the skin dose is the major factor determining effective dose calculation for charged particles. The results of the current study generally show that the ICRP-116 DCs for skin dose and effective dose are not reliable for charged particles.

• The Journal of Korean Academy of Prosthodontics
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• 제34권2호
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• pp.290-298
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• 1996

The effects of impression tray disinfection procedures on the bond strength of impression-material adhesive to two of types resin trays were evaluated with a tensile test. Autopolyme-rizing acrylic resin was formed into 1x1x1 cm cubes. A hook was attached to each cube with autopolymerizing acrylic resin. Perforated trays were fabricated with stops to maintain an even 3 cm of impression material over the resin block. Hook on the opposite side of the perforated tray permitted attachment of the metal plate to a mechanical testing machine. Before adhesive was applied, one third of the resin specimens were immersed in a 5% sodium hypochlorite solution : one third in a 2% glutaradehyde solution, and one third were kept in the "as fabricated" condition. Three products(Perfect ups, Exafine, and Exp-ress) of polyvynil siloxane impression material-adhesive system were evaluated. The resin-impression material-metal plate couples were attached to a mechanical testing machine and tensile forces were applied at a separation rate of 10 centimeters per second. The results were as follows; 1. Both disinfectant and adhesive had effects on bond strength values, but adhesive had more effect than disinfectant(p<0.01). However, there was no interaction between dinin-fectant and adhesive(p>0.01). 2. Mean bond strength values for the Perfect materials were about 85% less than that of the Exafine or the Express materials. However, there was no stastically significant difference between the mean bond strength values of the Exafine materials and the Express materials(p>0.05). 3. The use of disinfectants produced significant reduction in bond strength values(p<0.05). But there was no stastically significant difference between the mean bond strength values of the groups treated with disinfectants(p>0.05).

• Korean Journal of Veterinary Research
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• 제29권3호
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• pp.333-342
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• 1989

Effect of raising types and environmental conditions on the infection of Toxoplasma in the swine, the cat and the man were studied in Cheju Island from Sept. 1987 to Aug. 1988. Blood samples were taken from 214 conventionally raised swine in 6 villages and 506 swine raised in swine specialized farms, 122 cats raised under free moving or restraned conditions in 8 locations, 113 butchers, and 210 villagers. Toxoplasma antibody values of the blood sera were determined using the enzymelinked immunosorbent assay (ELISA). The eating type of viscera was also investigated by using questionaires 1. When ELISA method was used, the percentage of Toxoplasma infected swine among the conventionally raised and of those raised in swine specialized farms were 60.7% and 21. 390, respectively. The respective mean of antibody values (${\pm}SD$) were 0.589 (${\pm}0.310$) and 0.385 (${\pm}0.237$) and differed very significantly (p<0.01). A significant difference was also found in antibody values among 6 villages (p<0.05). 2. The mean infection percentage of toxoplasma in the cat was 38.2%. the infection percentage for cats raised under free-moving and re~;trained condition were 37.0% and 38.2% respectively. The respective antibody values(${\pm}SD$) for toxoplasma were 0.600(${\pm}0.614$) and 0.637 (0.645), and did not difference significantly. 3. The infection percentage of toxoplasma in villagers and butchers were 26.2 and 38.3% respectively. The respective antibody values (SD) for toxoplasma were 0.429(${\pm}0.195$) and 0.341 (${\pm}0.236$), and differed very significantly (p<0.01). There were also highly significant differences Pyo-sun and other village (p<0.01). 4. Analysis of the questionaires showed that 26.0% of 392 villages eated liver and some villagers eated other viscera.

• The Journal of Korean Medicine
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• 제37권3호
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• pp.27-38
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• 2016

Objectives: According to Korean Medicine theory, the skin color of LU10 serves as a diagnostic clue to dyspeptic symptoms. The aims of this study were (1) to find the difference of skin color in LU10 region between functional dyspepsia (FD) and healthy control (HC) and (2) to examine the relationship between LU10 skin color parameters and dyspeptic symptoms. Methods: 39 participants (29 FD and 10 HC) have participated in this study. They were asked to complete gastrointestinal scale (GIS), gastrointestinal symptom rating scale (GSRS), Nepean dyspepsia index (NDI), functional dyspepsia-related quality of life (FD-QoL), visual analogue scale (VAS) for dyspeptic symptoms, food retention questionnaire (FRQ) and cold heat questionnaire (CHQ). $L^*$ (luminance), $a^*$ (red-green balance) and $b^*$ (yellow-blue balance) values of LU10 region were calculated through digital images of the participant's hand. Then we evaluated test-retest reliability of $L^*$, $a^*$ and $b^*$ values of LU10 region. Additionally, we compared $L^*$, $a^*$ and $b^*$ values of LU10 between FD and HC, and examined the relationship between LU10 color parameters and seven questionnaires scores. Results: Only $L^*$ values in LU10 region were significantly higher in FD compared with HC. GIS scores and the subset scores of NDI had a positive correlation with $L^*$ values significantly. Correlation coefficients of test-retest reliability of skin color measurement of LU10 ranged from 0.871 to 0.936 representing very strongly statistically significant (P<0.001). Conclusions: We confirmed the difference of skin color in LU10 region between FD and HC, and relationship between LU10 skin color parameters and dyspeptic symptoms.

• Phonetics and Speech Sciences
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• 제5권4호
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• pp.99-107
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• 2013

The purpose of this study is to examine the relative distances among English front vowels in a message produced by 47 Korean and American speakers in order to better instruct pronunciation skills of English vowels for Korean English learners. A Praat script was developed to collect the first and second formant values(F1 and F2) of eight words in each sound file which was recorded from an internet speech archive. Then, the Euclidean distances were measured between the three vowel pairs: [i-ɛ], [i-ɪ], and [ɛ-æ]. The first vowel pair [i-ɛ] was set as the reference from which the relative distances of the other two vowel pairs were measured in percent in order to compare the vowel sounds among speakers of different vocal tract lengths. Results show that F1 values of the front vowels produced by the Korean and American speakers increased from the high front vowel to the low front vowel wih differences among the groups. The Korean speakers generally produced the front vowels with smaller jaw openings than the American speakers did. Secondly, the relative distance of the high front vowel pair [i-ɪ] showed a significant difference between the Korean and American speakers while that of the low front vowel pair [ɛ-æ] showed a non-significant difference. Finally, the Korean speakers in the higher proficiency level produced front vowels with higher F1 values than those in the lower proficiency level. The author concluded that Korean speakers should produce the front high vowels distinctively by securing sufficient relative distance of the formant values. Further studies would be desirable to examine how strong the Korean speakers' English proficiency correlate with the relative distance of target words of comparable productions.