• Journal of the Korean Society for Aviation and Aeronautics
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• v.16 no.1
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• pp.46-57
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• 2008

Since the 90's, Korean Air transport market has been more expanded because of economic growth, the construction of airport infrastructure, and the advent of low cost carrier. Especially, the air traffic demand in Busan metropolitan area has been increasing steadily. Therefore, in this paper, we developed a new forecasting model which could expect the future air traffic demand in Busan area. This model is developed by regression analysis using social-economic variables such as GRDP, income, and the number of people, and dummy variables, for instance, KTX opening, Japan economic depression, SARS and so on. Result from demand forecasting by this new model suggests that the new airport system is needed in order to sustain the increasing air traffic demand in Busan area.

• Proceedings of the KSPS conference
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• 2005.11a
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• pp.51-54
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• 2005

This paper analyzes the vocal tract area estimation algorithm used as a part of a speech analysis program to help deaf children correct their pronunciations by comparing their vocal tract shape with normal children's. Assuming that a vocal tract is a concatenation of cylinder tubes with a different cross section, we compute the relative vocal tract area of each tube using the reflection coefficients obtained from linear predictive coding. Then, obtain the absolute vocal tract area by computing the height of lip opening with a formula modified for children's speech. Using the speech data for five Korean vowels (/a/, /e/, /i/, /o/, and /u/), we investigate the effects of the sampling frequency, frame size, and model order. We compare vocal tract shapes obtained from deaf and normal children's speech.

• Speech Sciences
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• v.4 no.1
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• pp.19-34
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• 1998

The author collected and compared midsagittal, coronal, coronal oblique, and transversal images of Korean monophthongs /a, i, e, o, u, i, v/ produced by a healthy male speaker using 1.5 T MR, VISION. Area was measured by computer software after tracing the cross-section at different points along the tract. Results showed that the width of the oral and pharyngeal cavities varied compensatorily from each other on the midsagittal dimension. Formant frequency values estimated from the area functions of the seven vowels showed a strong correlation (r=0.978) with those analyzed from the spoken vowels. Moreover, almost all of 35 students who listened to the synthesized vowels from area data perceived the synthesized vowels as equivalent to the spoken ones. Movement of constriction points of vowel /u/ with wider lip opening sounded /i/ and led to slight changes in vowel quality. Jaw and tongue movement led to major volume variation with an anatomical limitation. Each comer vowel varied systematically from a somewhat constant volume of the average area. Thus, the author proposed that any simulation studies related to vocal tract area variation should reflect its constant volume. The results may be helpful to verify exact measurement of the vocal tract area through vowel synthesis and a simulation study before having any operation of the vocal tract.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5820-5825
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• 2014

The aim of this study was to verify the suitability or unsuitability of Korean body types by measuring the opening force criteria of an air pressurized access door to a smoke control zone. The opening force criteria were verified by comparing the NFSC 501A, NFPA 92A and BS-EN 12101-6 based on the body standards information from the Korean Agency for Technology and Standards. When measuring the opening forces, the posture of the body should be standing upright and pushing an access door with the right hand, which is a criterion for designing doors. As a result of analyzing the actual measurement results, the pushing force of men and women in their 30's was the maximum value and the forces in those in their 60's was the minimum value. In addition, the deviations in the pushing forces varied considerably. As a result of comparing the NFSC 501A, the men showed lower values than the criteria in every gender and age variable except for the 20's, 30's and 50's variable. A comparison of the criteria of NFPA 92A showed that the mean of the measured values from every gender and age was also lower than the criteria. In addition, when comparing the criteria of BS-EN 12101-6, it was found that the men in every age variable were higher than the criteria. On the other hand, the women in every age variable were lower than the criteria. Therefore, considering the Korean body type against the Western body type, it was decided that the opening force of an access door to a smoke control area to make a downward adjustment should be 110 N in the local criteria. Furthermore, the criteria should consider the characteristics of buildings and users because an optional application of the international standard is not necessarily suitable for local situations.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.4
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• pp.265-280
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• 2021

Population density due to urbanization is making people interested in underground space development and much interest in TBM construction with low vibration and noise. This led to a lot of research on TBM. However, research on the characteristics of the cutterhead opening of the TBM equipment being occluded under the ground conditions under which it is excavated is insufficient. Accordingly, a study was conducted to investigate clogging of the cutterhead opening during the shield TBM rolling. To identify the clogging of cutterhead openings in SHIELD TBM equipment, the reduced model experiment was divided into clay rate (10%, 30%, 50%, 60%), cutterhead opening rate (30%, 50%, 60%), and cutterhead rotation direction (one-way, two-way) and rotational speed (3 RPM) and conducted in 36 cases. Results of scale model test on shield TBM clogging, it was analyzed that the ground condition containing clay soil increased the clogging effect in both directions than the unidirectional rotation, and that the lower the rotational speed of the cutterhead, the less the clogging effect. Accordingly, the direction of cutterhead rotation, rotational speed and opening rate are calculated by taking into account ground conditions during ground excavation, the clogging effect can be reduced. It is believed to be effective in saving air as the clogging effect is reduced. Therefore, this study is expected to be an important material for domestic use of shield TBM.

• Journal of the Korean Wood Science and Technology
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• v.14 no.1
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• pp.3-44
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• 1986

In order to obtain the basic physical and mechanical properties of steel wire reinforced particleboard, particleboards were formed with large particles through 2.11 mm (12 meshes) and retained on 1.27mm (20 meshes) sieves and small particles through 1.27mm (20 meshes) and retained on 0.42mm (60 meshes) sieves from the plywood mill wastes of meranti (Shorea spp.) in the form of pallmanchips, applying urea-formaldehyde resin as an adhesive on the particle surface in 10 percent on the oven dried weight of particles, and arranging steel wires of 1mm in diameter 5,10,15,20, and 25mm in longitudinal and transverse direction with crossing in the mid of the board depth in single layer boards, 10mm in longitudinal or transverse direction without crossing in two layers and 10mm in longitudinal and transverse directions with and without crossing in three steel wire layers boards. The stepwise 9-minutes-multi-pressing schedule in 5 minutes at 35 kgf/$cm^2$, 2.5 minutes at 25 kgf/$cm^2$. and 1.5 minutes at 15 kgf/$cm^2$ was applied for $300{\times}200{\times}13$mm board at the temperature of 160$^{\circ}C$ in a hot press. Specific gravity, thickness swelling, bending properties of modulus of rupture (MOR), modulus of elasticity(MOE), work to proportional limit, and work to ultimate load, internal bond (IB), and screw holding power(SHP) of the reinforced boards were analyzed on the wire openings and wire layers. The results obtained are summarized as follows; 1) In specific gravity, particleboards with large particles and small particles had higher value with more steel wire placements and more steel layers composition, 2) Particleboards with large particles in accordance with more steel wire liners composition gave very poor thickness swelling. 3) The mechanical properties of particleboards formed with large or small particles were reinforced with more steel wire layers. Therefore, bending strength was improved in modulus of rupture, modulus of elasticity, and work to ultimate load. Especiallv, particleboards with two or three steel wire layers showed the tension lamination effect when the steels in lower steel wire layer were oriented parallel to the board length. 4) The modulus of rupture, modulus of elasticity, and work to ultimate load in bending varied with opening area, distance of lengthwise wires multipled by distance of transverse wires. Particleboards formed with large particles resulted in higher value in modulus of rupture with 1.5-3 $cm^2$ opening area, 1-2cm distance between transverse wires, and 1.5-2.5cm distance between lengthwise wires. Particle boards formed with small particles showed higher value with 0.5-1.5$cm^2$ or 3.75-6.25 $cm^2$ opening area, 0.5 or 2.5cm distance between transverse wires. 5) In modulus of elasticity, particleboards formed with large particles with one steel wire layer suggested higher value with 5-3$cm^2$ opening area, 1-2.5cm distance between transverse wires and also 1-2.5 cm distance between lengthwise wires. Particleboards formed with small particles showed higher value with 0.75-1.25$cm^2$ or 3-6.25$cm^2$ opening area and 0.5 or 2.5cm distance between transverse wires. 6) Particleboards formed with large particles gaved higher value in work to ultimate load with 1-3$cm^2$ opening area. Particleboards formed with small particles showed increasing tendancy with decreasing opening area. 7) In internal bond and screw holding power, particleboards formed with large particles had increasing value in two and three steel wire layers compositions, but particleboards formed with small particles showed no difference. Particleboards formed with large particles containing one steel wire layer showed no difference in internal bond and screw holding power, and particleboards formed with small panicles containing one steel wire layer resulted in increasing value in internal bond and decreasing value in screw holding power in accordance with increase in opening area.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.451-460
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• 2010

There are many types of remodeling, however, engineers and architectures preferred to merge two or more separate units to one very spacious unit. Performing this type of remodeling, in the case of wall dominant apartments, requires partial removal of structural wall causing a concern of structural integrity. However, there are insufficient studies about partial removal, that is, openings. Presently, ACI standard have no clear way to evaluate the effect of opening on the structural wall. AIJ has the provision about strength reduction factor '$\gamma$'. However, this reduction factor cannot exactly evaluate the reduction effect of openings because this factor '$\gamma$' was determined through the elastic analysis. Therefore, in this study, 2 structural wall specimens were tested and many test results from previous studies were collected. Using these data, this study performed statistical analysis about strength of structural wall which have the opening in wall panel. And this study performed parametric study verifying shear strength reducing effect by opening area. In the results of statistical study, previous reduction factor show very conservative results because this equation did not consider other factors, reinforcement ratio and aspect ratio of openings, which was affect the shear strength of shear walls. Therefore we performed parametric study based on the test data and suggest new equation for shear strength reduction factor '$\gamma$'.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.383-389
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• 2020

Mesoporous silica solid catalysts modified with sulfonic acid were prepared for cationic ring-opening polymerization of octamethylcyclotetrasiloxane (D₄). Two sets of MCM-41 (1.7 and 2.8 nm) and SBA-15 (8.1 and 15.9 nm) with different pore sizes were used as catalyst supports. The surface of silica materials was modified with (3-mercaptopropyl)trimethoxysilane by silylation reaction and oxidized to sulfonic acid. The structures of the prepared catalysts were examined by X-ray diffraction and nitrogen adsorption-desorption. The pore size, specific surface area, and pore volume of the modified solid catalysts decreased slightly. In addition, the modification of the sulfonic acid on the silica surface was confirmed by using infrared spectroscopy and nuclear magnetic resonance spectroscopy. To observe the effect of the particle size on the catalytic activity, it was observed with a scanning electron microscope. The catalysts were used to synthesize PDMS through a ring-opening polymerization of D₄, and the conversion and polymerization rate of the polymerization reaction depended on the pore size, specific surface area, particle size, and particle agglomeration of the catalysts. In order for the polymerization rate, the catalyst prepared with SBA-15 of 8.1 nm pore size had the fastest reaction rate and showed the best catalytic activity.

• Mycobiology
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• v.44 no.3
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• pp.180-186
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• 2016

Trichoderma species are able to persist on living sapwood and leaves of cacao (Theobroma cacao) in an endophytic relationship. In this research, we evaluated the ability of Trichodema asperellum introduced at the incision site in the bark for side grafting with the concentration of 4 g/10 mL, 4 g/100 mL, and 4 g/1,000 mL (suspended in water) in suppressing vascular streak dieback (VSD) incidence and promoting growth of side grafts in the field. The incidence of VSD in two local clones of cacao, MCC1 and M04, without application of T. asperellum was 71.2% and 70.1% at 21 wk after grafting, respectively. However, when the two clones were treated with a concentration of 4 g/10 mL T. asperellum, the incidence was 20.6% and 21.7%, respectively, compared to 29.1% and 20.9% at 4 g/100 mL and 18.2% and 15.6% at 4 g/1,000 mL. By comparing to the control, the treatment with the same concentrations of T. asperellum listed above, the total number of stomata in MCC1 decreased by 41.9%, 30.2%, and 14.0% and in M04 by 30.5%, 21.9%, and -2.5% (exception), respectively. Otherwise, the total area of stomata opening increased by 91.4%, 99.7%, and 28.6% in MCC1 and by 203.8%, 253.5%, and 35.9% in M04, respectively. Furthermore, the number of buds and branches treated with a mixture concentration on the the two clones increased by 90.7% and 21.7%, respectively. These data showed that the application of T. asperellum to cacao scions while grafting can decrease VSD incidence in side grafts and increase growth of grafts in addition to decreasing total number of stomata, increasing total area of opened stomata, and increasing number of buds and branches.

• Journal of the Korean Institute of Gas
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• v.7 no.4 s.21
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• pp.53-60
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• 2003

Accident occurred by gas explosion in house or building causes damage on lives and properties. To avoid secondary damage, this study drew area ratio of vent area with the experiment for pressure variation with vent area versus building volume by selection of model for different size and shapes of vent area generated by explosion. In addition, Appropriate model was chosen to predict the damage by minimum pressure with the experiment of opening are shapes. This model can prevent secondary damage with the selected vent area and shape to guarantee building safety.