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RFM을 이용한 고해상도 위성영상의 기하보정에 관한 연구
전형섭,정용주,조기성 전북대학교 공학연구원 ( 구 전북대학교 공업기술연구소 ) 2003 工學硏究 Vol.34 No.-
Manufacturing of the large scale map using the high-resolution satellite data requires high-precision geometric correction, and for this the location ephemeris data as like the location and attitude of the satellite sensor, which is an orbit component model, is needed, but in IKONOS satillite these are not porvided because of the business technology protection. Therefore, in this study, as the basic course for obtaining the ground coordinates from the IKONOS satellite imagery, using the ground control point without the satellite aid data it derived RMF's coefficient in the geometric correction of high-resolution satellite imagery, did the geometric correction using RFM and evaluated accuracy, and then finally it could be gotten the follwing conclusion as the result of evaluating the RMF's usefulness. First, as the result of applying to the least square method, to derive the coefficient of RFM using the ground control point, in the case of using the third order expression, it could derived the exact coefficient value about 0.686 pixel(m) of the root mean square error. Second, as the result of comparing the polynominal expression model and RFM, by using RFM it could improve the root mean square error more than 1.5 pixel. Third, RFM is very sensitive to the Z value information, and it could know that using the polynominal expression is more efficient than RFM is if the Z value infromation is inaccurated.
소아복부둔상시 저혈량성 쇽과 연관된 복부전산화 단층촬영술의 유용성
박광철,조수형,조남수,박진,변주남 대한응급의학회 2000 대한응급의학회지 Vol.11 No.4
Background: We reviewed retrospectively the clinical features and contrast material-enhanced computed tomography(CT) after blunt abdominal trauma demonstrated a characteristic hypoperfusion complex. Our purpose were to evaluate the hypothesis that children with this "hypoperfusion complex" CT finding were associated with a tenuous hemodynamic state, severe injury and a poor outcome. Methods: Between January 1996 and December 1999, 39 consecutive children who sustained blunt trauma and were suspected clinically of having intraabdominal injury underwent CT. Demographic data, blood pressure, indication for CT, pediatric trauma score(PTS) and Glasgow coma score(GCS) were recorded at the time of the initial examination. Results: Three of the 39 children(8%) demonstrated a characteristic finding at CT which was described as the hypoperfusion complex. The "hypoperfusion complex" was present in the 3 of the 39 traumatized children(8%), but was the main radiographic finding in the 3 of the 14 children with a severe pediatric trauma score(PTS<8) and in the 3 of the 6 children with a Glasgow coma score(GCS<8) who were examined with CT. Conclusion: The CT findings in all children with the hypoperfusion complex by definition included marked, diffuse dilatation of the intestine with fluid; abnormally intense contrast enhancement of the bowel wall, mesentery, kidney and/or pancreas; decreased caliber of the abdominal aorta and inferior vena cava(IVC); and moderate to large peritoneal fluid collection. This "hypoperfusion complex" is a relatively rarely observed in injured children but appears to be associated with severe injury and a poor outcome. The pediatric trauma score provides a useful profile of injury severity in children. Prompt diagnosis of hypovolemic shock is important so that supportive therapy can be instituted to prevent further metabolic abnormalities and their potential cardiotoxic effects. In summary, the intense multiorgan enhancement pattern seen in the hypoperfusion complex indicates tenuous hemodynamic stability and is associated with a poor outcom.
An Extended Heat Release Model of Turbulent Premixed Flame Response to Flow Perturbations
Ju-Hyeong Cho(조주형),Kook-Young Ahn(안국영),Seung Wook Baek(백승욱) 한국연소학회 2009 KOSCOSYMPOSIUM논문집 Vol.- No.39
A generalized model of the turbulent flame response to acoustic perturbation, including mixture ratio perturbation, was analytically formulated by accounting for a distributed heat release along the mean flame front with a kinematic model that incorporates turbulent premixed flame development. The effects of turbulent flame development were evaluated on two types of flame transfer functions: one is due to velocity fluctuation, the other is due to equivalence ratio fluctuation. A developing turbulent flame speed plays a significant role in both cases. A developing turbulent flame reduces the magnitude of the flame transfer function due to velocity fluctuation particularly at low frequency regime while it enhances the transfer function magnitude due to equivalence ratio perturbation. Both transfer functions show similar behaviors in the phase characteristics: the phases of both transfer functions with a developing flame speed increase more rapidly than those with a constant flame speed, which implies that the time delay between flow perturbations and the corresponding heat release response increases with a developing turbulent flame.
Experimental investigations on combustion characteristics of a swirl-stabilized premixed burner
Ju Hyeong Cho,Han-SeokKim,Min Kuk Kim,Jeong Jae Hwang,이상민,Ta Kwan Woo 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.2
Experimental investigations have been conducted to understand the combustion characteristics of a swirl-stabilized double-cone premixed burner used for industrial gas turbines for power generation. NOx and CO emissions, extinction limit, combustion noise, pressure loss, and wall temperature distributions were measured for various operating conditions. Results show that NOx emissions are decreased with increasing air/fuel ratio or decreasing air load unless the air load is too small. CO emissions are also decreased with increasing air/fuel ratio, leading to a positive correlation between NOx and CO emissions. Flame extinction limit is reduced with increasing air flow rate as the flow residence time is reduced. Combustion noise has its peak amplitude at the frequencies of 150 or 300 Hz, which are considered to be the resonance frequencies of the longitudinal mode of the combustor. The noise level at the peak frequency is maximized when the flame is considered to be located near the burner exit. Pressure loss is decreased with the A/F ratio as the flame moves downstream out of the burner.