• Particle and aerosol research
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• v.14 no.2
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• pp.41-47
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• 2018

Numerical analysis was conducted to characterize particle deposition onto a heated horizontal semiconductor wafer in vacuum environment. In order to calculate the properties of gas surrounding the wafer, the gas was assumed to obey the ideal gas law. Particle transport mechanisms considered in the present study were convection, Brownian diffusion, gravitational settling and thermophoresis. Averaged particle deposition velocities on the upper surface of the wafer were calculated with respect to particle size, based on the numerical results from the particle concentration equation in the Eulerian frame of reference. The deposition velocities were obtained for system pressures of 1000 Pa~1 atm, wafer heating of 0~5 K and particle sizes of $2{\sim}10^4nm$. The present numerical results showed good agreement with the available experimental ones.

• Journal of the Korean Ceramic Society
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• v.48 no.5
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• pp.390-395
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• 2011

The objective of our study was to produce an imitation bone material consisting of hydroxyapatite with a compact and spongy structure. This study shows the ideal content of $SiO_2$ and the sintering temperature to produce imitation bone that has the mechanical properties of natural bone. On the basis of our determination of the ideal conditions, a compact part was produced and its mechanical properties were tested. A compact part made of 0.5 wt% $SiO_2$ and sintered at $1350^{\circ}C$ showed excellent mechanical properties. The bioactivity of the compact part under this condition was tested, and it was found to be bioactive. The porous part was produced by controlling the powder size, and the dual structure was manufactured by combining the compact and porous parts. A water permeability test confirmed that the dual structure had an interconnected pore structure. Therefore, this dual-body structure is feasible for use in the creation of implants.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.4
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• pp.1904-1926
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• 2016

Iris recognition for biometric personnel identification has gained much interest owing to the increasing concern with security today. The image quality plays a major role in the performance of iris recognition systems. When capturing an iris image under uncontrolled conditions and dealing with non-cooperative people, the chance of getting non-ideal images is very high owing to poor focus, off-angle, noise, motion blur, occlusion of eyelashes and eyelids, and wearing glasses. In order to improve the accuracy of iris recognition while dealing with non-ideal iris images, we propose a novel algorithm that improves the quality of degraded iris images. First, the iris image is localized properly to obtain accurate iris boundary detection, and then the iris image is normalized to obtain a fixed size. Second, the valid region (iris region) is extracted from the segmented iris image to obtain only the iris region. Third, to get a well-distributed texture image, bilinear interpolation is used on the segmented valid iris gray image. Using contrast-limited adaptive histogram equalization (CLAHE) enhances the low contrast of the resulting interpolated image. The results of CLAHE are further improved by stretching the maximum and minimum values to 0-255 by using histogram-stretching technique. The gray texture information is extracted by 1D Gabor filters while the Hamming distance technique is chosen as a metric for recognition. The NICE-II training dataset taken from UBRIS.v2 was used for the experiment. Results of the proposed method outperformed other methods in terms of equal error rate (EER).

• Korean Journal of Community Nutrition
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• v.4 no.4
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• pp.554-560
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• 1999

This study was conducted to find adolescent females perception of body image. The survey was carried out by self-questionnaires with 463 female school and college students in Daegu. Analysis of data was done using t-test, and ANOVA with the SAS computer program. The average height, weight and BMI of the subjects were 161.2cm, 53.4kg and 20.51kg/$m^2$. It appeared that 33.3% of the subjects were off the normal range of body weight ; in particular 25.1% of the subjects were under weight. While the subjects’perception of their own current body image was not distorted, they were dissatisfied with their body image because they wanted a very thin figure. Subjects were divided into 3 groups -underweight, normal weight, overweight-according to their current body size. Their perceptions of ideal and desired figures differed significantly between the groups, but they thought a thinner figure than normal body image as ideal and desired body image even in overweight group. As a result, dissatisfaction of body image in the overweight group was significantly larger than the normal-weight group, and that of the normal-weight group was larger than the underweight group. Percentages of weight control attempt were 51.7% and 64.7% in the normal weight and underweight subjects, respectively. Subjects were divided into 2 groups according to their weight control experience : those who have attempted, and who have not attempted. Weight control attemptees had a higher level of dissatisfaction with their body image than non-attemptees, both because weight control attemptees were fatter, and they perceived a thinner figure as an ideal and as a desired body image thin non-attemptees. From the results of this study, we confirmed that one of reasons of excessive weight control behavior among adolescent females was distorted perception about ideal body image.

• Nutritional Sciences
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• v.5 no.4
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• pp.245-255
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• 2002

This study was designed to investigate body image, objective and subjective measurements of body size and shape, eating behavior, and weight control practices in 650 Korean adolescent girls; 500 of the subjects were 14 years old and enrolled in middle schools, while the remaining 150 were 17 years old and enrolled in high schools. Subjects responded anonymously to a self-administered questionnaire. The results showed that average height and weight of the subjects were 157cm and 49.5kg, respectively, while subjects ideal heights and weights averaged 164cm and 48kg, respectively. The ideal adult body heights and weights proposed by the subjects averaged 172cm and 55kg respectively. Over 50% of the subjects were dissatisfied with their body image; the degree of dissatisfaction with body image was higher in those who believed themselves to be fat. Most of the subjects wanted to lose weight and had tried to lose weight. Self-reported weight control practice methods included reducing food intake (31.9%), skipping meals (29.6%), exercise (25.8%), using slimming machines (6.9%), and using diet pills (5.1%). The heavier the subjects weight was, the greater the difference between the subjective and objective evaluations of body size. The body image scores of subjects who perceived themselves as fat were significantly lower than those of subjects who perceived themselves as normal or underweight. The difference between subjective and objective evaluations of body size, and the degree of obesity, were significantly higher in those subjects who had experience of weight control than those who had no experience of weight control. These results suggest that nutrition and health education programs for adolescent girls should be researched and implemented in order to establish a more realistic body image, positive habits in weight control, and healthful eating habits.

• Archives of Plastic Surgery
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• v.32 no.4
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• pp.416-420
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• 2005

Ideal results of augmentation mammaplasty consist of symmetry, natural shape, soft feeling and inconspicuous scar. In addition, patient's preferences about size and shape should be included. Static implants could not perfectly satisfy patients' desires for size and shape, but expandable implants enable to change the volume after the operation. From September 2001 to September 2004, 76 patients(150 breasts) underwent breast augmentation using permanent expandable implant. The procedure was unilateral in 2 women and bilateral in 74 women. Age ranged from 19 to 50 years(mean, 29 years). Fifty nine patients underwent simple augmentation mammaplasty, 7 patients were corrected of their severe asymmetry, 2 patients with the congenital breast deformity underwent mammaplasty using this, and 2 patients who had undergone unilateral mastectomy were reconstructed of their breasts using expandable implant. There were no definite complications such as capsular contracture, implant rupture, asymmetry. And there reported little dissatisfaction about the size. The permanent expandable implants might be good alternatives in cases of ordinary breast augmentation as well as tissue deficient patients, asymmetry, congenital anomaly, and breast reconstruction.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.4
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• pp.592-597
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• 2015

3D-IC is a novel semiconductor packaging technique stacking dies to improve the performance as well as the overall size. TSV is ideal for 3D-IC because it is convenient for stacking and excellent in electrical characteristics. However, due to high-density and micro-size of TSVs, they should be tested with a non-invasive manner. Thus, we introduce a TSV test method on test prober without a direct contact in this paper. A capacitive coupling effect between a probe tip and TSV is used to discriminate small TSV faults like voids and pin-holes. Through EM simulation, we can verify the size of eye-patterns with various frequencies is good for TSV test tools and non-contact test will be promising.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.7
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• pp.741-753
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• 2008

This paper explores the throughput performance of CSMA/CA-based DCF protocol over both ideal channels and fading channels with payload size at the MAC layer in the 802.11a wireless LAN. In the ideal channel, there are no errors and at the transmission cycle there is one and only one active station which always has a packet to send and other stations can only accept packets and provide acknowledgements. In the fading channel, bit errors appear in the channel randomly and the number of stations is assumed to be fixed. And each station always has packets for transmission. In other words, we operate in saturation conditions. Up to now conventional research work about DCF throughput analysis of IEEE 802.11 a wireless LAN has been done over the ideal channel, but this paper is done over the Rayleigh/Ricean fading channel. So, the ratio of received average energy per bit-to-noise power spectral density $E_b/N_o$ is set to 25 dB and the ratio of direct-to-diffuse signal power in each sub-channel $\xi$ is set to 6 for combined Rayleigh/Ricean fading channel. In conclusion, it is shown that the saturation throughput is always less than the maximum throughput at all the payload size and the higher the transmission rate be, the higher the decreasing rate of saturation throughput compared to the maximum throughput be.

• Journal of the Korean Home Economics Association
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• v.41 no.6
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• pp.119-129
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• 2003

This study was peformed to establish the standard size system to be required for the production of brassiere. The subject were 155 Korean twenties-aged women and were directly measured anthropometrically. From 27 measurements, 5 factors were extracted through factor analysis. The accumulative contribution ratio is 76.92％. Factor 1 indicates the degree of obesity around the chest, factor 2 is the drooping degree of breast, factor 3 is the contours and prominence, factor 4 is the breast breadth and breadth of bust point, factors 5 is the volume of breast. The subject were classified into 3 cluster as their breast types through cluster analysis. Type 1 is the closest to the ideal breast shape and not too droopy. This group belonged to 75A. Type 2 has small breast and belonged to 70AA group. Type 3 is the obesest and has the biggest and droopy breast. This group belonged to 75B. The distribution of size of brassiere had 3 sections from 70 to 80 showing a rate of 81.94% and the sin of the cup had 4 sections from AAA cup to B cup showing a rate of 89.70％. The production ratio of each brassiere size, it was found that the brassiere size of highest production ratio was 75A(16.39％) in type 1,70AA(16.27%) in type 2, and 75B(13.72％) in type 3. This suggests that it is necessary to adjust for the production rate of brassieres.

• Journal of the Korean Ceramic Society
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• v.35 no.8
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• pp.807-812
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• 1998

Mechanical properties of two types of polycrystlline {{{{ { { Ti}_{3 }SiC }_{2 } }} with different grain size were investigated. A fine grain {{{{ { { Ti}_{3 }SiC }_{2 } }} has a higher fracture strength and hardness. Plot of strength versus Vickers indentation load indicated that {{{{ { { Ti}_{3 }SiC }_{2 } }} has a high flaw tolerance. Hertzian indentation test using a spherical indenter was used to study elastic and plastic behavior in {{{{ { { Ti}_{3 }SiC }_{2 } }}. Indentation stress-strain curves of each material are made to evaluate the plasticity of {{{{ { { Ti}_{3 }SiC }_{2 } }} Both find and coarse grain {{{{ { { Ti}_{3 }SiC }_{2 } }} showed high plasticity. In-dentation stress-strain curve of coarse grain {{{{ { { Ti}_{3 }SiC }_{2 } }} deviated even more from an ideal elastic limit in-dicating exceptional plasticity in this material. Deformation zones were formed below the contact as well as around the contact area in both materials but the size of deformation zone in coarse grain {{{{ { { Ti}_{3 }SiC }_{2 } }} was much larger than that in fine grain {{{{ { { Ti}_{3 }SiC }_{2 } }} Intragrain slip and kink would account for high plasticity. Plastic behavior of {{{{ { { Ti}_{3 }SiC }_{2 } }} was strongly influenced by grain size.