• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.4
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• pp.25-30
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• 2010

Our new metamaterial structure patch antenna improves the gain of ordinary metamaterial patch antenna. The structure of new metamaterial cover is made by removing central $7{\times}7$ lattices out of $9{\times}9$ lattices. Also, the metamaterial covers can be easily fabricated using ordinary substrates. Measurement results of a patch antenna, a metamaterial patch antenna and our proposed metamaterial patch antenna show that the gain of the proposed metamaterial patch antenna is about 3dB higher than that of the ordinary metamaterial patch antenna.

• Human Ecology Research
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• v.58 no.2
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• pp.215-228
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• 2020

Underlying dress forms for high coverage patterns are very important in the dress industry. Size 9 from brand D was chosen according to the analysis that it was the best option because a dress should have a large allowable range in one size. The criteria for selection were the dress form with a waist circumference of 63.50 centimeters, which is close to the standard size of women in Korea. Brassieres for dresses were included to enhance the aesthetic value of the correction process in producing a basic dress pattern. An experimental torso pattern was applied to evaluate the fit and suitability of the dress form that was also later verified in the process of the dress works. Three dresses were produced and presented on the chosen study dress form. The research procedures are as follows. First, the sell-through rates and feedbacks were collected from the dress form vendor. Second, a literature survey on dresses and a dress company investigation were conducted. Third, the amount of body dimension changes due to the use of a bra in the dresses were examined. Fourth, after the correction of the dress form, the torso pattern was made by draping. Fifth, the torso experimental clothing made of muslin material was evaluated. Sixth, the dress works of the top design were presented using the size 9 basic pattern developed by brand D.

• Journal of Korea Foundry Society
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• v.29 no.5
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• pp.238-243
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• 2009

This study has been carried out to investigate the cooling ability improvement of diecasting mold by decompression cooling system. The decompression cooling system was applied to the new/used oil pump cover molds. The temperature of the surface mold applied the decompression cooling system fell to 15 degrees, especially in case of the used mold. The defect ratio of the oil pump cover manufactured by decompression cooling system has decreased from 2.8 percent to 0.2 percent. According to the results of the cooling ability improvement of diecasting mold by decompression cooling system, the decompression degree and supply pressure were set up the control item to apply the decompression cooling system to the diecasting mold in the industry field.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.173-180
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• 2001

This research is aimed at investigating the dynamic response of cut-and-cover tunnel to seismic waves. We carried out shaking table test which is used a 1/40-scale(the width of prototype tunnel is about 14.2m, the height is about 8.5m) model for this research, and we analyzed the effect of depth of tunnel and slope of the ground in relation to the dynamic responses of tunnel. As a result of the test, the stress and acceleration along the tunnel decreased accordingly to the depth of increment, and this phenomenon is caused by the increase of the confining effect of ground. Also, the dynamic responses of tunnel showed a tendency to rise according as ground declined gently. In comparison the result of shaking table test with that of structural analysis on ordinary condition, we conclude that seismic waves do not affect cut-and-cover tunnel when the depth of tunnel is over the diameter of tunnel.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.3
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• pp.71-78
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• 2011

This paper propose image steganalysis scheme based on independence between parent and child subband on the multi-layer wavelet domain. The proposed method decompose cover and stego images into 12 subbands by applying 3-level Haar UWT(Undecimated Wavelet Transform), analyze statistical independency between parent and child subband. Because this independency is appeared more difference in stego image than in cover image, we can use it as feature to differenciate between cover and stego image. Therefore we extract 72D features by calculation first 3 order statistical moments from joint characteristic function between parent and child subband. Multi-layer perceptron(MLP) is applied as classifier to discriminate between cover and stego image. We test the performance of proposed scheme over various embedding rates by the LSB, SS, BSS embedding method. The proposed scheme outperforms the previous schemes in detection rate to existence of hidden message as well as exactness of discrimination.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.4
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• pp.469-474
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• 2015

In ultrasonic spray pyrolysis deposition, a precursor solution is evaporated by an ultrasonic atomizer, then gas-carried into a furnace where the solute is separated from the water vapor. After condensation, polymerization, and nucleation, the solute oxide forms a thin film. To improve the deposition efficiency, the ultrasonic atomizer was studied to optimize the evaporated gas flow. The vat cover was redesigned, using three versions with different inlet factors being tested through a computational fluid dynamic analysis as well as a water evaporation experiment. The atomization rate with a hemispherical cover with a $30^{\circ}$ inlet was found to be 2.4 times higher than that with the original. This improvement was verified with fluorine-doped tin oxide spray pyrolysis deposition. The film obtained with the modified vat cover was 2.4 times thicker than that obtained with the original vat cover.

• Atmosphere
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• v.26 no.3
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• pp.401-412
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• 2016

A 3D sonic anemometer has been installed at Yongpyong alpine slope since Oct. 23th 2014 to observe the slope winds and to analyze turbulent characteristics with the change in surface cover (grass and snow) and the synoptic wind strength. Eddy covariance method has been applied to calculate the turbulent quantity after coordinate transformation of a planar-fit rotation. We have carefully selected 3 good episodes in the winter season (23 October 2014 to 28 February 2015) for each category (9 days in total), such as grass and snow covers in case of weak synoptic wind condition, and grass cover of strong synoptic wind. The diurnal variations of the slope winds were well developed like the upslope wind in the daytime and downslope wind in the nighttime for both surface covers (grass and snow) in the weak synoptic forcing, when accordingly both heat and momentum fluxes significantly increased in the daytime and decreased in the nighttime. Meanwhile, diurnal variation of heat flux was not present on the snow cover probably in associated with significant fraction of sunlight reflection due to high albedo especially during the daytime in comparison to those on the grass cover. In the strong synoptic regime, the most dominant feature at Yongpyong, only the southeasterly downslope winds were steadily generated irrespective of day and night with significant increases in momentum flux and turbulent kinetic energy as well, which could suggest that local circulations are suppressed by the synoptic scale forcing. In spite of only one season analysis applied to the limited domain, this kind of an observation-based study will provide the basis for understanding of the local wind circulation in the complex mountain domain such as Gangwon in Korea.

• ALGAE
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• v.27 no.1
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• pp.33-42
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• 2012

Population ecology of Palmaria palmata is described from the intertidal zone of Digby Neck and adjacent islands of Nova Scotia. The primary objectives were: to evaluate the difference in habitat specialization and population structure of P. palmata between harvest and non-harvest shores, and to characterize differences in thallus structure and frond sizes between epilithic and epiphytic populations. Harvest shores were gently sloping boulder fields with boulders typically about 0.5-1.0 m with dense cover of P. palmata on many of the rocks. Non-harvest shores (with or without P. palmata) consisted of boulders that were smaller or larger than harvest shores, or bedrock; when P. palmata was present on nonharvest sites it was typically epiphytic on other algae (e.g., Fucus spp., Mastocarpus stellatus, Devaleraea ramentacea). Harvestable epiphytic populations occurred only in high current areas. While there was little difference in average cover of P. palmata harvest and non-harvest shores ($31.2{\pm}13.7%$ vs. $19.4{\pm}7.3%$, mean ${\pm}$ standard deviation [SD]), the cover of P. palmata on harvest shores was highly skewed such that individual boulders often had >90% cover while adjacent rocks had little. Frond length of large fronds was greater on harvested shores, and mean frond density ($g\;m^{-2}$) was three times higher than the mean density on the non-harvested shores. Frond lengths of entire epiphytic and epilithic frond complements of 119 thalli from harvest beaches showed no difference in mean size of the largest fronds, and no difference in frond number per holdfast when epiphytic and epilithic thalli were compared.

• Structural Engineering and Mechanics
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• v.56 no.6
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• pp.899-916
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• 2015

Upgrading or strengthening of existing reinforced concrete (RC) infrastructure is an emerging demand nowadays. Near Surface Mounted (NSM) technique is very promising approach for flexural strengthening of RC members. However, premature failure such as concrete cover separation failure have been a main concern in utilizing this technique. In this study, U-wrap end anchorage with carbon fiber reinforced polymer (CFRP) fabrics is proposed to eliminate the concrete cover separation failure. Experimental programs were conducted to the consequence of U-wrap end anchorage on the flexurally strengthened RC beams with NSM-steel. A total of eight RC rectangular beam specimens were tested. One specimen was kept unstrengthened as a reference; three specimens were strengthened with NSM-steel bars and the remaining four specimens were strengthened with NSM-steel bars and U-wrap end anchorage using CFRP fabrics. A 3D non-linear finite element model (FEM) was developed to simulate the flexural response of the tested specimens. It is revealed that NSM-steel (with and without end-anchors) significantly improved the flexural strength; moreover decreased deflection and strains compared with reference specimen. Furthermore, NSM-steel with end anchorage strengthened specimens revealed the greater flexural strength and improve failure modes (premature to flexure) compared with the NSM-steel without end anchorage specimens. The results also ensured that the U-wrap end anchorage completely eliminate the concrete cover separation failure.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.179-182
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• 2007

In recent, recycling of plastic material has became a major issue due to the landfills and environmental problem. This study investigated fluidity of thermoplastic vulcanizate(TPV), which is for automobile component parts such as weather strip in order to replace ethylene propylene rubber (EPDM). So, using the spiral flow test mold and panel cover mold, we conducted an experiment on fluidity of TPV with injection molding. As results of injection molding experiment, the recycled TPV's flow length was a little bit longer than virgin TPV and a case of panel cover, the filled weight was almost same quantity.