• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.4
• /
• pp.216-222
• /
• 2002

Brake Moan is a laud and strong noise occurring at any vehicle speed over 2 mph as a low frequency in below 600Hz. In this study, we targeted to shift the unstable mode that causes the brake moan from the moats frequency range to sufficiently higher frequency range to avoid the moan phenomenon. We simulated the finite element model and found out the nodes in which the brake moan occurs the most and we regarded the boundary and its relationship between the brake pad and the rotor as a spring coefficient k. With the binary set of the spring coefficient k, we finally used genetic algorithm (GA) to get the optimal topology of the brake pad and its shape to avoid the brake moan. The final result remarkably shows that genetic algorithm can be used in topology optimization procedures requiring complex eigenvalue problems.

• Proceedings of KOSOMES biannual meeting
• /
• 2009.06a
• /
• pp.53-54
• /
• 2009

The influence of atmospheric aerosol on satellite ocean color data were evaluated using SeaWiFS monthly standard mapped image products. The atmospheric optical thickness (AOT) was increased in spring and summer, and it showed the strong positive correlation with remote sensing reflectance, normalized waterleaving radiance /solar irradiance, at 555 nm (Rrs555) which is a component of the satellite chlorophyll estimation. Such the high AOT and high Rrs555 pixels showed overestimation of satellite chlorophyll in spring, especially in the area which showed large phytoplankton absorption which 1s expressed by low remote sensing reflectance at 443, 490 and 510 nm (Rrs 443, Rrs490 and Rrs510).

• Water for future
• /
• v.11 no.2
• /
• pp.62-69
• /
• 1978

Interstational and interseasonal analyses of the correlation and variability in the seasonal and annual precipitation for 10 basic synoptic stations in South Korea, on the basis of rainfall record of over 40 years, are carried out. It is found that the climatic regions of precipitation could be classified by means of the interstational analysis for the correlations. Corrleation coefficients in interstational relationship of precipitation are lowest in autumn which characterizeds a strong locality while the highest value shows a relatively weak locality in winter. Interseasonal relationship between summer and winter precipitation shows mostly 10 percent significant level with all positive values. The magnitude of the variation coefficients are appeared to be in the order of winter, autumn, spring and summer. It is shown that the highest which is winter ranges between 0.33 0.58, and for the lowest summer, 0.26-0.44, respectively in the areal distribution of the coefficient. The secular changes of the variation coefficient in the recent trend show increases in spring at two station; Seoul and Incheon, in summer at Busan and in autumn at two stations; Busan and Incheon while in winter show devreases at the whole stations. An annual variation seems to show generally a constant trend as whole for all the stations.

• Tribology and Lubricants
• /
• v.29 no.1
• /
• pp.7-12
• /
• 2013

Turbine power control devices at a nuclear / thermoelectric power plant lead to failure by creating mechanical shocks and strong vibrations that are due to the strong elasticity of a spring and the inertia of the valve face during its rapid movement to block steam. To ensure durability of the turbine power control device, which is the main component in the power plant, it is necessary to develop a device that can prevent such vibrations. In this study, a cushion mechanism is added to the head of the hydraulic servo actuator, which is a turbine power control device. Moreover, the cushion mechanism, which includes various modifies shapes and orifices is investigated dynamically through modeling and simulations.

• Food Science and Preservation
• /
• v.14 no.6
• /
• pp.633-638
• /
• 2007

Changes in organic acid, mineral, color, curcumin and bitter taste of Curcuma longa L. (autumn woolgeom in Korean) and Curcuma atomatica Salib (spring woolgeom) were investigated according to picking time. Oxalic and lactic acid were gradually increased, and then malic acid and malonic acid were decreased by extending the picking time. Total organic acid was increased by extending the picking time and then decreased after January of the coming year. Minerals were increased by extending the picking time and decreased slightly after the coming year. Hunter color index, L, a and b, was increased by extending the picking time. Contents of curcumin in spring woolgeom was slowly increased by extending the picking time and autumn woolgeom was $1.8{\sim}2.5$ times higher than spring woolgeom. Intensity of bitter taste in two woolgeoms were not different by picking time and extracting solvents. Bitterness of spring woolgeom was strong as compared to autumn woolgeom.

• Atmosphere
• /
• v.31 no.4
• /
• pp.377-394
• /
• 2021

The recent largest forest fire in the Yeongdong region, Goseung/Okgae fires of 2019 occurred during YangGang wind event. The wind can be locally gusty and extremely dry, particularly in the complex terrain of Yeongdong. These winds can cause and/or rapidly spread wildfires, the threat of which is serious during the dry spring season. This study examines the spatial variability of the surface wind and its coupling with the upper atmospheric wind using the data during the IOP of the Gangwon Yeongdong Wind Experiments (G-WEX) conducted in 2020 and the data during YangGang wind event on 4~5 April 2019. In the case of IOPs, strong wind at the surface with a constant wind direction appears in the mountain area, and weak wind with large variability in wind direction appears from foothill to the coast in the vicinity of Gangneung region. However, in the 2019 event, strong wind at the surface with a constant wind direction appears in the entire region from the mountain to the coast, even with the stronger wind in the coast than in some part of the mountain area. The characteristics of the upper atmospheric wind related with the spatial distribution of surface wind show that during IOPs of G-WEX, a strong downdraft exists near the mountaintop in the level of about 1 to 4 km. However, in the 2019 event a strong downdraft is reinforced, when its location moves toward the coast and descends close to the ground. These downdrafts are generated by the breaking of mountain waves.

• Journal of Korean Medical classics
• /
• v.22 no.1
• /
• pp.121-130
• /
• 2009

Traditionally, Korean Medicine put emphasis on the treatment and health-preserve method that corresponds with circulation of nature. And acupuncture is no exception to this rule. In "Hwangjenaegyeong(黃帝內經)", some chapters present method that is changed according to the seasons. Among the chapters, there are some difference, but we can find a general theory. In spring, Yanggi(陽氣) is coming out but not strong and cannot diffuse. so the Yanggi(陽氣) hang up the middle of outer layer. Therefore, we can take some acupoints around the muscle interspace[分腠] or tiny branches of Meridian[孫絡]. In summer, Yanggi(陽氣) flourish and boil all around of the outer layer. So, we can take some acupunctural points from skin to the yang-meridian. In both fall and winter, five su point[五輸穴] make up almost of point. in fall, yanggi begin convergence. we can remove the Eum-pathogen[陰邪] and help the normal convergence by using Stream point[腧穴], River point[經穴] and Sea point[合穴]. In winter, Eum surround so solidly that the neo Yanggi(陽氣) cannot come out. So, we can break the yin by using Well point[井穴] and make be strong by Spring point[滎穴]. If we Study the method that correspond with the seasonal circulation more, we will be able to treat diseases more minutely.

• Journal of Korean Society for Atmospheric Environment
• /
• v.29 no.6
• /
• pp.780-788
• /
• 2013

This study attempted to determine important meteorological parameters related to airborne pollen concentrations in urban areas. Hourly pollen measurement data were prepared from a regular sampling with a volumetric Burkard spore trap at a site in the Ulsan city, during the spring season (March~May) of 2011. Results showed that the daily mean and maximum concentrations for total pollen counts during the spring season were statistically significantly correlated with both air temperature and wind speed; daily mean pollen concentration was the most highly related to daily maximum temperature (r=0.567, p<0.001). It was also identified that pollen concentration has a stronger relationship with wind speed at the rural site than at the urban one, which confirms that strong wind conditions over the pollen sources area can be favorable for pollen dispersal, resulting in increases in airborne pollen concentrations downwind. From the results of an oak-pollen episode analysis, it was found that there was a significant relationship between hourly variation of oak pollen concentrations and dynamic meteorological factors, such as wind and mixing height (representing the boundary layer depth); especially, a strong southwestern wind and elevated mixing height was associated with high nocturnal concentrations of oak pollen. This study suggests that temperature, wind, and mixing height can be important considerations in explaining the pollen concentration variations. Additional examination of complex interactions of multiple meteorological parameters affecting pollen behavior should be carried out in order to better understand and predict the temporal and spatial pollen distribution in urban areas.

• Ocean and Polar Research
• /
• v.28 no.3
• /
• pp.339-352
• /
• 2006

Seasonal and tidal variations of density stratification in the Saemangeum waters are investigated based on synoptic CTD observations between July 2003 and September 2005. CTD data used in this study are those obtained after closing the dike No. 4 and before closing the two final gaps, the Sinsi and the Garyeok, on the Saemangeum tidal harrier. A total of 19 field campaigns comprehend a wide temporal spectrum, that is, few seasons, spring and neap tides, and high and low waters. In addition, ADCPs were anchored and CTDs were cast at three stations for 25 h in July 2005. Water columns are vertically homogeneous in autumn and winter. The vertical homogeneity persists in spring but with an occasional weak stratification in i:he northern part of the Gogunsan Islands. Increased reshwater runoff tends to stabilize the water columns and strong density stratification is established in summer. The mean potential energy anomaly (PEA) in summer used as a stratification parameter is the largest $(27.7\;J\;m^{-3})$ in the northern part of the Gogunsan Islands where the Geum River discharge dominates, the smallest $(16.9\;J\;m^{-3})$ is in the inner area of the barrier, in between the two $(21.6\;J\;m^{-3})$ in the southern part of the Gogunsan Islands. Whereas the stratification is generally strengthened in summer, strong winds or large tidal currents over the shallow depths frequently destratify the water column near the mouth of river runoff inside the tidal barrier. Periodic stratification, the development of stratification on the ebb and its breakdown on the flood, occurs in the mid-area inside the barrier induced by the tidal straining, which can also be found in the results of 25 h observation.

• The Research Journal of the Costume Culture
• /
• v.11 no.5
• /
• pp.711-720
• /
• 2003

The purposes of the study were to categorize eroticism expressed in modern fashion and to find out any significant difference in erotic expressions among designer brands and fashion seasons. The research methods was a documentary analysis. The documentary materials were 180 photographs randomly selected from fashion photographs of 3 major designer brand collections, from 1995 S/S to 2000 A/W. The data were analyzed by contents analysis, frequency, crosstabs. Results were as follows; 1) The existence of erotic expressions in modern fashion was found in 107 (59.4%) out of 180 fashion photographs and the eroticism was one of the major themes in the later 1990's fashion. 2) The erotic expression in the modern fashion were categorized into 5 categories exposure, adhesion, transparency, exposure+adhesion, and adhesion+transparency. The major erotic expression was exposure which was followed by adhesion and transparency. 3) The degree of erotic expression were separated into 3 levels-strong, medium, weak. The erotic levels in the modern fashion ranged between medium and weak; medium level 43%, weak 42% and strong 15%. 4) The erotic expression and the degree of erotic expression showed differences according to three designer brands. Chanel brand used less erotic expression than Christian Dior or Givenchy. Christian Dior brand showed the tendency of strongest erotic level while the Chanel brand showed the weakest level. 5) The erotic expression and the degree of erotic expression showed differences according to fashion seasons. Spring and summer seasons used more erotic expression than autumn and winter. In spring and summer seasons, exposure and transparency were methods used more frequently for erotic expressions, while adhesion was stronger themes in autumn and winter seasons.