• Journal of the Korea Society of Computer and Information
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• v.16 no.4
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• pp.61-71
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• 2011

In this paper, we proposed the method for detecting text region on image using DCT-coefficient and transition-map analysis. The detecting rate of traditional method for detecting text region using DCT-coefficient analysis is high, but false positive detecting rate also is high and the method using transition-map often reject true text region in step of verification because of sticky threshold. To overcome these problems, we generated PTRmap(Promising Text Region map) through DCT-coefficient analysis and applied PTRmap to method for detecting text region using transition map. As the result, the false positive detecting rate decreased as compared with the method using DCT-coefficient analysis, and the detecting rate increased as compared with the method using transition map.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.5
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• pp.1310-1317
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• 2015

Two-phase flow boiling heat transfer in micro-channels was experimently investigated. The test section consisted of 15 rectangular micro-channels with a depth of 0.45mm, width of 0.20mm. The experiments were performed for heat fluxes ranging from 5.6 to 46.1kW/m2 and mass fluxes from 150 to 450kg/m2s using FC-72 as the working fluid. According to the results, at the low heat flux region, heat transfer coefficient strongly depends on the heat flux, while heat transfer coefficient at the high heat flux region was independent on the heat flux. Four correlations were used to predict the heat transfer coefficient. The measured heat transfer coefficient was compared with four correlations. It was found that Kaew-On and Wongwises's correlation well predicted the measured data, within the MAE of 40.3%.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.12 no.5
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• pp.502-510
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• 2000

Evaporation heat transfer characteristics were studied in a horizontal tube using R22/R114 non-azotropic refrigerant mixture. the heat transfer coefficient was high in the upper part for pure refrigerants, and heat transfer coefficient was low in the lower part for refrigerant mixtures. In the low quality region where nucleate boiling was dominant, the average heat transfer coefficient was low. In the region where forced convection was dominant, heat transfer coefficient was high. Results show that the heat transfer coefficient for pure refrigerants obtained by experiments were lower than those of Yoshida et al. but agreed well with Jung et al., and Chen et al. data. But the heat transfer coefficients for refrigerant mixtures were lower about 20% than those predicted by the equation for pure refrigerant.

• Wind and Structures
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• v.16 no.2
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• pp.193-211
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• 2013

This paper presents results from a wind tunnel study that examined the drag coefficient and wind flow over an asymmetric wave train immersed in turbulent boundary layer flow. The modeled wavy surface consisted of eight replicas of a statistically-valid hurricane-generated wave, located near the coast in the shoaling wave region. For an aerodynamically rough model surface, the air flow remained attached and a pronounced speed-up region was evident over the wave crest. A wavelength-averaged drag coefficient was determined using the wind profile method, common to both field and laboratory settings. It was found that the drag coefficient was approximately 50% higher than values obtained in deep water hurricane conditions. This study suggests that nearshore wave drag is markedly higher than over deep water waves of similar size, and provides the groundwork for assessing the impact of nearshore wave conditions on storm surge modeling and coastal wind engineering.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.385-386
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• 2002

The friction characteristics of contact region between vane tip and cam-ring is studied with an experimental device model. The radius of vane tip is less than 1 mm and sliding speed is lower than 10 m/s. The friction characteristics of the actual oil hydraulic vane pump is estimated on the basis of coefficient of friction. The coefficient of friction can be obtained by measuring the frictional forces in the contact region. The lubrication condition between vane and disk is modeled after the actual condition between the vane and cam-ring.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.9
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• pp.1796-1804
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• 1992

Profiles of soot volume fraction, average diameter and particle number density have been measured using a light scattering and extinction technique in a coannular propane diffusion flame at atmosperic pressure. Temperature profiles were also obtained using a thermocouple technique. Measurements show that soot is first observed to form low in the flame in an annular region inside the main reaction zone. At higher locations this annular region widen until entire flame is observed to contain particles. Soot volume fraction and particle diameter profiles peak some 1mm on the fuel side of peak temperature and increase with height to oxidation region. Number density of the flame core drop steeply from formation region to growth region and relatively invariant to some height and decay out at flame tip.

• Environmental and Resource Economics Review
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• v.33 no.1
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• pp.87-112
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• 2024

This study estimates the regional input-output table and GHG emissions in 2019 and then analyzes the economic effects of carbon taxes by region and industry in Korea. The GHG emission, emission coefficient, and emission induction coefficient are estimated to be higher in manufacturing-oriented metropolitan provinces. The GHG emission coefficient in the same industry varies from region to region, which might reflect the standard of product classification, characteristics of production technology, and the regional differences in input structure. If a carbon tax is imposed, production costs are expected to increase and demand and production will decrease, especially in the manufacturing industry, which emits more GFG. On the other hand, the impact of carbon taxes on each region is not expected to vary significantly from region to region, which might be due to the fact that those differences are mitigated by industry-related effects. Since the impact of carbon taxes is expected to spread to the entire region, close cooperation between local governments is necessary in the process of implementing carbon neutrality in the future.

• Atmosphere
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• v.22 no.1
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• pp.57-71
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• 2012

Influences of orographic and ocean effect, which depend on the detailed geographic characteristics, upon winter time (December-February) precipitation in the Yeongdong region are investigated. Most of precipitation events in the Yeongdong region during the wintertime are associated with moist northeasterly (coming from the northeast direction) winds and also the spatial distribution of precipitation shows a great difference between Mountain area (Daegwallyeong) and Coastal area (Gangneung). The linear correlation coefficient between the meteorological variables obtained from NCEP/NCAR Reanalysis Data and precipitation amount for each precipitation type is calculated. Mountain type precipitation is dominated by northeasterly wind speed of the low level (1000 hPa and 925 hPa) and characterized with more precipitation in mountain area than coastal area. However, Coastal type precipitation is affected by temperature difference between ocean and atmosphere, and characterized with more precipitation in coastal area than mountain area. The results are summarized as follows; In the case of mountain type precipitation, the correlation coefficient between wind speed at 1000 hPa (925 hPa) and precipitation amount at Daegwallyeong is 0.60 (0.61). The correlation is statistical significant at 1% level. In the case of coastal type precipitation, the correlation coefficient of temperature difference between ocean and 925 hPa (850 hPa) over the East sea area and precipitation amount at Gangneung is 0.33 (0.34). As for the mountain type precipitation, a detailed analysis was conducted in order to verify the relationship between precipitation amount at Daegwallyeong and low level wind speed data from wind profiler in Gangneung and Buoy in the East Sea. The results also show the similar behavior. This result indicates that mountain type precipitation in the Yeongdong region is closely related with easterly wind speed. Thus, the statistical analysis of the few selected meteorological variables can be a good indicator to estimate the precipitation totals in the Yeongdong region in winter time.

• The KSFM Journal of Fluid Machinery
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• v.7 no.5 s.26
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• pp.36-42
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• 2004

The effect of tip clearance height on the three-dimensional flow and aerodynamic loss in the wake region of a high-turning turbine rotor cascade has been investigated with a miniature cone-type five-hole probe. Distributions of velocity magnitude, secondary velocity vectors, and total-pressure loss coefficient are presented for three tip gap-to-span ratios of h/s = 0.0, 0.5 and 1.0 percent. The result shows that with the increment of h/s, tip leakage vortex tends to be intensified and aerodynamic loss due to the leakage vortex is increased as well. In the case of h/s = 1.0 percent, aerodynamic loss in the tip-leakage flow region is found dominant in comparison with that in the passage vortex region. With increasing h/s, mass-averaged secondary loss coefficient has a greater portion in the mass-averaged total-pressure loss coefficient.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.440-447
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• 2000

In order to evaluate the cost effectiveness of seismic isolation for bridges in low and moderate seismic region, a method of calculation minimum life-cycle cost of seismic-isolated bridges under specific acceleration level and soil condition is developed. Input ground motion is modeled as spectral density function compatible with response spectrum for combination of acceleration coefficient and site coefficient. Failure probability is calculated by spectrum analysis based on random vibration theories to simplify repetitive calculations in the minimization procedure. Ductility of piers and its effects on cost effectiveness are considered by stochastic linearization method. Cost function and cost effectiveness index are defined by taking into consideration the characteristics of seismic isolated bridges. Limit states for calculation of failure probability are defined on superstructure, isolator and pier, respectively. The results of example design and analysis show that seismic isolation is more cost-effective in low and moderate seismic region than in high seismic region.