• Journal of Ocean Engineering and Technology
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• v.23 no.2
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• pp.81-86
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• 2009

Infrared thermography was used to determine the location, size, and depth of defects under the surface of M.C nylon. Defects were created in a specimen by back-drilling circular holes. These defects were located at the maximum temperature difference that occurred. The sizes of the defects could be calculated by means of the full width at half of the maximum temperature difference. The depth of a defect could be calculated by the peak time and the maximum temperature difference. The maximum temperature difference between a defect and normal part was decreased with the depth of the defect. And the peak time also slowly appeared with the depth of the defect.

• Journal of applied mathematics & informatics
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• v.8 no.1
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• pp.165-180
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• 2001

This paper presents a new difference scheme for numerical solution of stiff system of ODE’s. The present study is mainly motivated to develop an absolutely stable numerical method with a high order of approximation. In this work a double implicit A-stable difference scheme with the sixth order of approximation is suggested. Another purpose of this study is to introduce automatic choice of the integration step size of the difference scheme which is derived from the proposed scheme and the one step scheme of the fourth order of approximation. The algorithm was tested by means of solving the Kreiss problem and a chemical kinetics problem. The behavior of the gas explosive mixture (H₂+ O₂) in a closed space with a mobile piston is considered in test problem 2. It is our conclusion that a hydrogen-operated engine will permit to decrease the emitted levels of hazardous atmospheric pollutants.

• Bulletin of the Korean Mathematical Society
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• v.48 no.2
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• pp.413-426
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• 2011

Two types of new methods with variable time steps are proposed in order to valuate binary options efficiently. Type I changes adaptively the size of the time step at each time based on the magnitude of the local error, while Type II combines two uniform meshes. The new methods are hybrid finite difference methods, namely starting the computation with a fully implicit finite difference method for a few time steps for accuracy then performing a ${\theta}$-method during the rest of computation for efficiency. Numerical experiments for standard European vanilla, binary and American options show that both Type I and II variable time step methods are much more efficient than the fully implicit method or hybrid methods with uniform time steps.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.E1
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• pp.29-38
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• 2007

A cylindrical tube connection that has a voltage difference and is separated electrically by an insulator was modelled. The penetration efficiencies of charged particles passing through the connector tube were investigated. Typically, as the particle size decreases and the applied voltage difference increases, the penetration efficiency decreases. To assess the effect of the electrode geometry, various lengths of electric insulator and aerosol flow rate with a fixed tube length and tube diameter were used when calculating penetration efficiencies. The comparison of penetration efficiencies for various electrode geometry setups suggests that the penetration efficiency can be described as a function of the product of applied voltage and electrical mobility of charged particles. The diffusion loss from this and previous studies are compared. Further, an explicit form for penetration efficiency is provided as a function of a new non-dimensional parameter, $Es(=Z_pV/U_{avg}W);\;P_{es}=0.2{\cdot}{\exp}(-Es/0.6342)+0.8{\cdot}{\exp}(-Es/4.7914)$.

• Journal of the Korean Society of Clothing and Textiles
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• v.23 no.2
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• pp.185-195
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• 1999

The purpose of this study is to identify store image and clothing satisfaction of various clothing distribution type and is to compare the difference due to demographic variables. The data were obtained 407 housewives using questionnaire. The results were as follows. First Store image of clothing distribution types was found significant differences in product service atmosphere. Second Clothing satisfaction of clothing distribution types was founded significant differences in price brand name fashion design material sewing size. Third The new distribution types in general were not visited upon despite their high degree of recognition and using experience of new distribution types was founded significant differences in Store image of new distribution types. Fourth Among demographic variables significant difference in usage of the distributions was founded. Fifth Among demographic variables significant difference in usage of the distributions was founded. Fifth Among demographic variables significant difference in clothing satisfaction of the distributions was founded.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2003.05a
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• pp.4-4
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• 2003

Various Cu films were fabricated using sputtering and electroplating with and without additive, and their surface damages after annealing were investigated. After annealing at 43SoC, the difference between damage morphologies of the films was observed. In some films stress-induced grooves along the grain boundaries were observed, while in the others voids at the grain boundary triple junctions were observed. It was also observed that the stress-induced groove was formed along the high energy grain boundaries. It was found out that the difference of the morphologies of surface damages in Cu films depends on not process type but grain boundary characteristics. To explain the morphological difference of surface damages, a simple parameter considering the contributions of grain structures and grain boundary characteristics to surface and grain boundary diffusions is suggested. The effective grain boundary area, which is a function of grain size, film thickness and the fraction of high energy grain boundaries, played a key role in the morphological difference.

• Journal of Information Processing Systems
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• v.15 no.2
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• pp.261-270
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• 2019

In order to protect secret digital documents against vulnerabilities while communicating, steganography algorithms are applied. It protects a digital file from unauthorized access by hiding the entire content. Pixel-value-difference being a method from spatial domain steganography utilizes the difference gap between neighbor pixels to fulfill the same. The proposed approach is a block-wise embedding process where blocks of variable size are chosen from the cover image, therefore, a stream of secret digital contents is hidden. Least significant bit (LSB) substitution method is applied as an adaptive mechanism and optimal pixel adjustment process (OPAP) is used to minimize the error rate. The proposed application succeeds to maintain good hiding capacity and better signal-to-noise ratio when compared against other existing methods. Any means of digital communication specially e-Governance applications could be highly benefited from this approach.

• The Korean Journal of Community Living Science
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• v.19 no.1
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• pp.21-30
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• 2008

This study conducted a survey to compare the size of ready-made clothes for different body shapes and body sizes, and to discover the differences in satisfaction with the size of ready-made clothes. The subjects were women in their 208 and 308 from Busan and Gyeongnam. The women were classified into groups: normal weight, overweight, and obese, using the Body Mass Index (BMI). The comparison of the body size showed a significant difference among the shapes; the average BMI in overweight women was 24.2 while that of obese women was 27.6. For the clothing size for each body shape, obese women most often wore size 77 and size 88, regardless of the sizes of upper and lower garments. The size consistency of upper and lower garments was the lowest in obese women. However, in most of the shapes, women tended to choose larger-sizes for lower garments than for upper ones. The more obese the subject, the less inclined they were to wear garments for their real body size. Satisfaction with the clothing size was significantly different between body shapes; the more obese, the lower the level of satisfaction with the size. As well, satisfaction with the fit of clothing at certain parts was shown to be low especially in the bust measurement, shoulder width, upper garment length, crotch length, and thigh circumference. When surveyed about the use of alterations for different body shapes, the results were that over 65% of subjects did not alter upper garments regardless of their body shape. Comparatively, 68% or above of all body shapes did do alterations to lower garments for example, the length of pants or skirts.

• Food Science and Biotechnology
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• v.15 no.5
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• pp.721-727
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• 2006

This study was carried out to investigate the effect of hydrocolloids on the changes in physical properties of a model ice cream. The model ice cream contained water, sugar, skin milk powder, com oil, and 4 different hydrocolloid stabilizers (gelatin, pectin, hydroxyethylstarch, locust bean gum), was manufactured in a batch type freezer. The following physical characteristics of ice cream were examined: flow behavior, overrun, air cell size, ice crystal size, and melt resistance. With regard to flow behavior, all of aged mixes had a lower apparent viscosity relative to the mix before aging, and ice cream mix containing locust bean gum had the highest viscosity. Air cell size was observed to range from 20 to $38\;{\mu}m$, and ice cream with locust bean gum showed the largest size. There was an inverse correlation between overrun and air cell size. The ice crystal sizes of all samples ranged from 25 to $35\;{\mu}m$. Ice cream with added pectin contained the smallest ice crystal size, which was significantly difference from other stabilizers (p<0.05), and resulted in superior melt resistance with increased melting time compared to other samples.

• Journal of the Ergonomics Society of Korea
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• v.33 no.4
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• pp.299-311
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• 2014

Objective: The aim of this study was to develop a method for measuring breast size from three-dimensional (3D) body scan image data. Background: Previous bra studies established reference points by directly contacting the subject's naked skin to determine the boundary of the breast. But some subjects were uncomfortable with these types of measurements. This study examined noncontact methods of extracting breast reference points from 3D body scan data that were collected while subjects were wearing standardized soft bras. Method: 3D body scan data of 32 Korean women were analyzed. The subjects were selected from the Size Korea 2010 study. The breast landmarks were identified by graphic analyses of slicing contour lines on 3D body scan data. Results: Three methods determining bra cup size were compared. The M1 and M2 methods determined cup size by calculating the difference between bust girth and under-bust girth. The M3 method determined bra cup size by measuring breast arc length. Conclusion: The researchers proposed an anthropometric bra cup sizing system with the breast arc length (M3 method). It was measured from the geometrically defined landmarks on the 3D body scan slicing contour lines. The new bra cup size was highly correlated with breast depth. Application: The noncontact measuring method used in this study can be applied to the ergonomic studies measuring sensitive body parts.