• 한국컴퓨터정보학회논문지
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• 제16권4호
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• pp.61-71
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• 2011

본 논문은 DCT계수와 천이지도 분석을 이용하여 영상 내 자막영역을 검출하는 방법에 대해 제안한다. 기존 DCT계수 분석방법을 이용한 문자영역탐지 방법은 검출률은 높으나 오검출률이 매우 높은 단점이 있고, 천이지도를 이용한문자영역 탐지 방법은 임계값이 정적이기때문에 문자영역 검증단계에서 실제문자영역이 기각되는 일이 빈번히 발생한다. 이러한 문제점을 해결하기 위해 DCT계수 분석방법을 이용하여 유망문자영역맵을 작성하고 이를 천이지도를 이용한 문자영역탐지 방법에 적용하여 임계값을 단계별로 정한다. 그 결과로서 DCT계수 분석을 이용한 문자영역검출방법에 비해 오검출률이 크게 감소하였으며, 기존 천이지도를 이용한 문자영역검출 방법보다 검출률이 크게 향상되었다.

• 수산해양교육연구
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• 제27권5호
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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%.

• 설비공학논문집
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• 제12권5호
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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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• 제16권2호
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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.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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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.

• 대한기계학회논문집
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• 제16권9호
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• pp.1796-1804
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• 1992

본 연구에서는 동심확산화염내에 생기는 매연 입자의 크기와 농도를 광산란 소멸법으로 보다 정확히 측정하여 궁극적 목적인 매연입자 제어의 기반을 조성하고자 한다.

• 자원ㆍ환경경제연구
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• 제33권1호
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• pp.87-112
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• 2024

이 연구는 2019년 지역산업연관표와 지역별 및 산업별 온실가스 배출량을 추정하여 우리나라 온실가스 배출현황 및 탄소중립을 위한 탄소세 부과의 경제적 효과를 지역별 및 산업별로 분석하였다. 분석결과 제조업 중심의 광역자치도에서 온실가스 배출량, 배출계수 및 배출유발계수가 높게 추정되었다. 동일한 산업일지라 하더라도 온실가스 배출계수가 지역에 따라 다른 것으로 나타났는데, 이는 대분류 기준에 따른 상품 분류, 생산기술의 특성, 생산요소 투입구조의 지역별 차이 등에 기인하는 것으로 추정된다. 한편 탄소세가 부과될 경우 온실가스 배출량이 많은 제조업을 중심으로 생산비용이 상승하고 수요 및 생산이 감소할 것으로 예측되었다. 이에 비해 탄소세 부과가 각 지역에 미치는 영향은 지역별로 차이가 상대적으로 크지 않을 것으로 예측되었는데, 이는 지역별로 산업비중이 달라 탄소세 부과가 지역에 미치는 직접적인 영향이 다를지라도 산업연관효과에 의해 그 차이가 완화되기 때문인 것으로 판단된다. 이처럼 탄소세 부과의 영향은 특정 지역에 집중되지 않고 전 지역에 파급될 것으로 예상되는 만큼 향후 탄소중립 이행과정에서 지자체 간의 긴밀한 협조가 필요할 것으로 생각된다.

• 대기
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• 제22권1호
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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.

• 한국유체기계학회 논문집
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• 제7권5호
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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.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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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.