• Fashion & Textile Research Journal
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• v.20 no.4
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• pp.457-463
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• 2018

This study examined the water absorption and drying properties of the thirteen types of the knitted fabrics for sports wear. These physical properties were analysed with relation to the constituent fiber cross-sectional shape and structure parameters of the knitted fabrics by regression analysis. Absorption and drying properties of the knitted fabric specimens were increased with increasing the porosity of the constituent yarns, which was attributed to the capillary channels in the yarns. The water absorption and drying properties were increased and decreased with increasing tightness factor and stitch density of the knitted fabric. The absorption property of the knitted fabric for perspiration absorption and fast dry sport-wear clothing was mostly influenced mostly by fiber cross-sectional shape and its characteristics, whereas, drying property was dependent on the structural parameters of the knitted fabric such as tightness factor and stitch density. Therefore, superior perspiration absorption and fast drying knitted fabric could be obtained in the fabric structure with optimum tightness factor and stitch density, and constituent yarn structure with non-circular fiber crosssection and high porosity. GATS method and MMT method are used to measure sweating fast drying properties and it is necessary to carry out studies using these measurement methods in order to compare with the results of this study.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.16 no.4
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• pp.89-96
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• 2017

A cable tray is a structure made of metal or a non-combustible material that supports cables in the electrical wiring of buildings. Cable trays should be developed to meet the various requirements of the construction site. In this study, a design system was developed to calculate the maximum support load and the maximum deflection according to the cross-sectional shape of the cable tray. The cross-sections of cable trays were modeled by combining linear and arc elements, and cross-sectional characteristics such as the 2nd moment of area were calculated. The distributed load and the concentrated load were applied to the cable tray using the Euler beam theory, and then the deflection profiles and maximum stress were calculated. To verify the developed system, deflection distributions and maximum stresses for two types of cable trays were calculated and compared. The maximum deflection and maximum stress errors calculated from the developed system were found to be less than 4% compared with numerical analysis results.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.8-13
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• 2020

Seamless pipes are fabricated by drilling a hole in a cylindrical material and drawing the material to the desired diameter. These pipes are used in environments where high reliability is required. In this study, the pipe drawing process was simulated using DEFORM, a commercial finite element method (FEM) analysis program. The outer diameter of the steel cylinder used herein before drawing was 70 mm, and the target outer diameter was 58 mm. The drawing process consisted of two stages. In this study, the effect of cross-sectional reduction rate on the pipe was investigated by varying the cross-sectional reduction rate in each step to achieve the target outer diameter. The results of this study showed that the first section reduction rate of 26% and the second section reduction rate of 13.9% caused the lowest damage to the material. Moreover, the FEM simulation results confirmed the influence of the drawing die angle on the pipe drawing process. The drawing die angles of 15° in the first step and 9° in the second step caused the least damage to the material.

• Journal of the Korean Society of Clothing and Textiles
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• v.47 no.1
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• pp.123-136
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• 2023

To develop smart sportswear capable of measuring biometric data, we created a close-fitting pattern using two- and three-dimensional (2D and 3D, respectively) methods. After 3D virtual fitting, the tightness of each pattern was evaluated using image processing of contact points, mesh deviation, and cross-sectional shapes. In contact-point analysis, the 3D pattern showed high rates of contact with the body (84.6% and 93.1% for shirts and pants, respectively). Compared with the 2D pattern, the 3D pattern demonstrated closer contact at the lower chest, upper arm, and thigh regions, where electrocardiography and electromyography were primarily carried out. The overall average gap was also lower in the 3D pattern (5.27 and 4.66 mm in shirts and pants, respectively). In the underbust, waist, thigh circumference, and mid-thigh circumference, the cross-section distance between clothing and body was showed a statistically significant difference and evenly distributed in the 3D pattern, exhibiting more closeness. The tightness and fit of the 3D smart sportswear sensor pattern were successfully evaluated. We believe that this study is critical, as it facilitates the comparison of different patterns through visualization and digitization through 3D virtual fitting.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.709-710
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• 2012

• 한국도로학회:학술대회논문집
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• 2010.09a
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• pp.265-270
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• 2010

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.9
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• pp.1317-1321
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• 1989

The nonuniqueness of solutions to inverse scattering problems for the reconstruction of cross sectional permitivity distributions on dielectric cylinder is illustrated in view of numerical analysis based on the spectral inverse scattering scheme with the moment-method procedures. It is also shown that some additional treatmenents such as multiple measurements, various incidences, etc. are not effective to assure the uniqueness.

• Tuberculosis and Respiratory Diseases
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• v.46 no.5
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• pp.628-635
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• 1999

Background : Maximal expiratory flow rate is determined by the size of airway, elastic recoil pressure and the collapsibility of airway in the lung. The obstruction of expiratory flow is one of the major functional impairments of emphysema, which represents COPD. Nevertheless, expiratory narrowing of upper airway may be recruited as a mechanism for minimizing airway collapse, and maintaining lung volume and hyperinflation by an endogenous positive end-expiratory pressure in patients with airflow obstruction. We investigated the physiologic role of trachea in respiration in emphysema. Method : We included 20 patients diagnosed as emphysema by radiologic and physiologic criteria from January to August in 1997 at Seoul Municipal Boramae Hospital. Chest roentgenogram, high resolution computed tomography(HRCT), and pulmonary function tests including arterial blood gas analysis and body plethysmography were taken from each patient. Cross-sectional area of trachea was measured according to the respiratory cycle on the level of aortic arch by HRCT and calibrated with body surface area. We compared this corrected area with such parameters of pulmonary function tests as $PaCO_2$, $PaO_2$, airway resistance, lung compliance and so on. Results : Expiratory cross-sectional area of trachea had significant correlation with $PaCO_2$ (r=-0.61, p<0.05), $PaO_2$ (r=0.6, p<0.05), and minute ventilation (r=0.73, p<0.05), but inspiratory cross-sectional area did not (r=-0.22, p>0.05 with $PaCO_2$, r=0.26, p>0.05 with $PaO_2$, and r=0.44, p>0.05 with minute ventilation). Minute ventilation had significant correlation with tidal volume (r=0.45, p<0.05), but it had no significant correlation with respiratory frequency (r=-0.31, p>0.05). Cross-sectional area of trachea had no significant correlation with other parameters of pulmonary function including $FEV_1$, FVC, $FEV_1$/FVC, peak expiratory flow, residual volume, diffusing capacity, airway resistance, and lung compliance, whether the area was expiratory or inspiratory. Conclusion : Cross-sectional area of trachea narrowed during expiration in emphysema, and its expiratory area had significant correlation with $PaCO_2$, $PaO_2$, and minute ventilation.

• Journal of the Korean Society of Physical Medicine
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• v.5 no.4
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• pp.615-621
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• 2010

Purpose : The purpose of this study was to compare chronic LBP patients and asymptomatic subjects on measures of multifidus size (cross-sectional area;CSA, thickness) and symmetry (proportional difference of relatively larger side to smaller side). Methods : Data were obtained from 12 asymptomatic subjects without a prior history of LBP (8 females, 4 males), and a retrospective audit was undertaken of records from 12 chronic low back pain patients (8 females, 4 males). CSA and Thickness of the lumbar multifidus muscles was measured from axial T1-weighted magnetic resonance images(MRI). Results : The results of the analysis showed that chronic LBP patients had significantly smaller multifidus CSA and thickness than asymptomatic subjects at L4-5 vertebral levels(p<.05). The asymmetry between sides was seen at L4- L5 vertebral level in patients with chronic low back pain presentations(p<.05). Conclusions : MRI provided a quantitative measure of change between asymptomatic subjects and chronic low back pain patients of multifidus muscle. MRI identified significant differences in cross-sectional area and thickness and helps to evaluate clinically and plan the treatment modalities of LBP.

• Journal of the Korean Home Economics Association
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• v.44 no.6 s.220
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• pp.163-174
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• 2006

The purpose of this research was to examine the level and trends in household clothing expenditure in Korea. Raw data sets produced by the National Statistical Office from the Family Income and Expenditure Survey from 1991 to 2004 were used to support time-series and cross-sectional analyses. The clothing expenditures decreased severely and quickly during the economic crisis of late 1997 through 1998, then increased slowly after the economic crisis until 2003, only to slightly decrease again in 2004. The ratio of clothing expenditure to total household expenditure decreased from 8.03% in 1991 to 5.11% in 2004. This decrease in relative clothing expenditure was greater in the lower income group than in the middle and high income groups. Clothing expenditure patterns were unique and differed from other household expenditures. Although the economic crisis in the late 1990s affected Korean consumers' clothing expenditure, clothing expenditure patterns showed a more fundamental and structural change from 1991 to 2004, with the overall decrease in such expenditure resulting from the concurrent increase in educational and information-communication related expenditures. Clothing expenditure was shown to be luxurious through cross-sectional analysis, but necessary through time-series analysis.