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      • SCOPUSKCI등재

        심폐바이패스없이 심박동상태에서 시행한 관상동맥우회술후 중기 개통율

        이철,장우익,임청,김기봉,채인호,오병희,이명묵,박영배,Lee, Cheul,Chang, Woo-Ik,Lim, Cheong,Kim, Ki-Bong,Chae, In-Ho,Oh, Byung-Hee,Lee, Myoung-Mook,Park, Young-Bae 대한흉부심장혈관외과학회 2001 Journal of Chest Surgery (J Chest Surg) Vol.34 No.8

        배경: 심폐바이패스없이 심박동상태에서 시행하는 관상동맥우회술 후의 각종 도관들의 1년째 개통율을 심패바이패스하의 심정지상태에서 시행하는 통상적 관상동맥우회술 및 심폐바이패스하의 심박동상태에서 시행한 관상동맥우회술 후의 1년재 개통율과 각각 비교하고 그 차이를 알아보고자 하였다. 대상 및 방법: 심폐바이패스없이 심박동상태에서 시행한 관상동맥우회술(I군; n=122)의 결과를 심폐바이패스하의 심정지상태에서 시행하는 통상적 관상동맥우회술(II군; n=65) 및 심폐바이패스하의 심박동상태에서 시행하는 관상동맥우회술(III군; n=19)의 결과와 비교, 분석하였다. I 군에서는 수술 직후와 수술후 1년째에 관상동맥조영술이 시행되었고, II군 및 III군에서는 수술후 1년째에서 시행되었다. 도관의 개통정도는 A(excellent), B(fair), 혹은 O(occluded)의 3등급으로 평가하였다. 결과: I, II, III군에서의 평균 원위 문합수는 각각 3.1$\pm$1.1, 3.7$\pm$0.9, 3.6$\pm$0.9개 이었다. I 군에서는 92%(112/122)의 환자들에서 퇴원 전 관상동맥조영술이 시행되었는데 개통율 (A+B)은 동맥 도관이 96.4%(162/168), 복재정맥이 85.6%(160/187) 이었다. 74%(90/122)의 환자들에서 술후 1년째 관상동맥조영술이 시행되었으며, 개통율은 동맥 도관이 97.89%(132/135), 복재정맥이 67.9%(106/156) 이었다. II군에서는 65%(42/65)의 환자들에서 술후 1년째 관상동맥조영술이 시행되었다. 개통율은 동맥 도관이 93.5%(43/46), 복재정맥이 88.3%(98/111) 이었다. III군에서는 89%(17/19)DML 환자들에서 술후 1년째 관상동맥조영술이 시행되었다. TRO통율은 동맥 도관이 100%(19/19), 복재정맥이 86.8%(33/38) 이었다. 결론: 세 군간에 동맥 도관들의 1년째 개통율은 유의한 차이를 보이지 않았다. 심폐바이패스 없이 심박동상태에서 시행하는 관상동맥우회술후 복재정맥의 개통율은 수술 직후에도 동맥 도관에 비하여 유의하게 낮았으며(p<0.001), 술후 1년째 복재정맥 개통율 또한 II군(p<0.001) 및 III(p<0.01)의 수술후 1년째 복재정맥 개통율에 비하여 유의하게 낮았다. 이러한 결과는 복재정맥을 이용하여 심폐바이패스없이 시행하는 관상동맥우회술의 경우, 수술전후 항응고 요법에 특별한 주의가 필요할 것이라는 사실을 시사한다. The aim of this study was to compare one-year graft patency after coronary artery bypass grafting without cardiopulmonary bypass(OPCAB) with that of conventional CABG and that of on-pump beating CABG, and to demonstrate any differences in patency of various conduits among the three groups. Material and Method: We analyzed the results of OPCAB cases(group I; n=122) compared with those of conventional CABG cases(group II; n=65) and those of on-pump beating CABG cases(group III; n=19). In group I, coronary angiography(CAG) was performed immediately postoperatively and 1 year after surgery. In group II and III, CAG was performed 1 year after surgery. Graft patency was graded as grade A(excellent), grade B(fair), or grade O(occluded). Result: The average number of distal anastomoses in groups I, II, and II were 3.1$\pm$1.1, 3.7$\pm$0.9, and 3.6$\pm$0.9, respectively. In group I, postoperative CAG was performed in 92%(112/122) of patients before discharge. The patency rate(grade A+B) was 96.4$(162/168) for arterial grafts, and 85.6%(160/187) for saphenous vein grafts(SVG). One-year follow-up CAG was performed in 74%(90/122) of patients. The patency rate was 97.8%(132/135) for arterial grafts, and 67.9%(106/156) for SVG. In group II, one-year follow-up CAG was performed in 65%(42/65) of patients. The patency rate(grade A+B) was 93.5%(43/46) for arterial grafts, and 86.8%(33/38) for SVG. Conclusion: Our results demonstrated that the patency rate of SVG after OPCAB was significantly lower than that of arterial grafts in the early postoperative CAG(p<0.001), and was also significantly lower than those of SVG of group II(p<0.001) and group III(p<0.01) in the postoperative one-year CAG, although there was no significant difference is one-year patency of arterial grafts among the three groups. Our data suggest that a specific perioperative anticoagulant therapy may be advisable in patients undergoing OPCAB with SVG.

      • KCI등재

        성인 남녀의 스포츠활동참여 비교분석

        이철화(Chul Hwa Lee) 한국사회체육학회 2000 한국사회체육학회지 Vol.13 No.-

        The purpose of this study was to investigate the sport participation comparison men with women in during leisure time. The results from this study will provide basis data necessary to develope sport activity program for adults. The subjects in this study were 457 adults in largest cities. The data were analyzed using t-test, chi-square, discriminant analysis with the SAS program. The results were follows; First, the intensity of the motivation in adult sports participation was showed downward heath oriented type, hobby and recreation oriented type, family oriented type, self-developing, social oriented type. The woman of participation in sport activities was showed heath oriented type, family oriented type more than that of men. Second, adult sports participation was influenced the intensity of the family and friend`s encouragement. women was influenced spouse`s encouragement, and the perceived athletic ability was the strongest predictor of adult sports participation for both men and women. third, for sport participants, many adults participated in secondary involvement more than primary involvement, and primary involvement was lots of men more than women. Fourth, women perceived barriers more than men in sports participation. Men perceived barriers in the order of time, economic, social barriers, women perceived barriers in the order of economic, time, social barriers.

      • 초미세 결정립 TRIP 강의 미세조직 변화

        이철원(C. W. Lee),고영건(Y. G. Ko),남궁승(S. Namgung),신동혁(D. H. Shin) 한국소성가공학회 2009 한국소성가공학회 학술대회 논문집 Vol.2009 No.10

        Transformation induced plasticity (TRIP) steel consisting of ferrite, austenite, and bainite phases was regarded as an excellent candidate for automotive applications due to the good combination of ductility and strength. The aim of the present study was to understand the microstructural characteristics of ultrafine grained (UFG) TRIP low-carbon steel fabricated via equal channel angular pressing accompanied with intercritical-and isothermal-annealing treatments. When compared to coarse grained counterpart, only the volume fraction of austenite phase in UFG TRIP steel remained unchanged, but all other microstructural variables such as size and morphology were different. It was found that UFG TRIP steel showed the homogeneous distribution of each constituent phase, which was discussed in terms of annealing treatments done in this study.

      • KCI등재

        청소년들의 스포츠참여와 스포츠참여 장애지각

        이철화(Chul Hwa Lee) 한국사회체육학회 2001 한국사회체육학회지 Vol.16 No.-

        The purpose of this study was to investigate perception of constraints and participation in sports of adolescents in during leisure time. The data analysis was based on information had gathered from 709 adolescents in Chung Cheong Province. The data were analyzed using ANOVA and canonical correlation with the SAS programs. First, for the sports involvement of adolescents, boy student was stronger than girl student, the rural student was stronger than the urban student, the satisfied student of the school life was stronger than non-satisfied student of the school life, the group of middle incomes was stronger than that of low and high incomes. For three dimensions of sports involvement, adolescents had involved in sports in the order of cognitive, behavioral, affective involvement.. Second, for the constraints of sports involvement, the degree of barriers in boy student was stronger than girl student, the students who lived in middle city than the largest and countryside had more barriers, who satisfied in the school life than non-satisfied had more barriers, who lived in middle incomes than low and high had more barriers. For five dimensions of sports constraints, adolescents had barriers in the order of facilities, services and partners, economic, lack of knowledge. Third, for adolescents sports involvement, the cognitive and behavioral involvement in sports related sports participation constraints. For adolescents sports participation constraints, the barriers of individual and psychological, lack of knowledge, time related sports involvement.

      • 모바일 카메라를 이용한 지문인식을 위한 지문영역 추출 및 융선방향 추출 알고리즘

        이철한,이상훈,김재희,김성재,Lee Chulhan,Lee Sanghoon,Kim Jaihie,Kim Sung-Jae 대한전자공학회 2005 電子工學會論文誌-SP (Signal processing) Vol.42 No.6

        본 논문에서는 모바일 카메라를 이용한 지문인식 시스템 개발에서 지문영역 추출 및 융선 방향 정보 추출 방법에 대해 제안한다. 모바일 카메라로 획득한 지문영상은 기존의 지문센서(접촉식 센서)로 획득한 영상과 여러 가지 다른 특성을 나타낸다. 우선 모바일 카메라로 획득한 지문영상은 칼라영상이며, 배경영역이 획득 장소와 시간에 따라 변화가 심하고, 지문 융선과 골의 조도차가 접촉식 센서에서 획득한 영상보다 작아 노이즈에 대한 영향이 크다는 특징이 있다. 이러한 환경에서 지문영역을 추출하고자 손가락의 색 정보와 지문의 주파수 정보를 이용하여 초기영역을 설정하고 설정된 초기영역을 이용하여 영역확장 방법으로 지문영역을 추출하였다. 손가락의 색 정보는 학습과정을 통해 손가락 색의 확률 분포를 LUT (Look Up Table)기법을 이용해 모델하였고, 주파수 정보는 초점이 맞는 손가락 영역과 초점이 맞지 않는 배경영역의 영상 주파수 특성 차이를 이용하였다. 지문 방향 정보 추출에서는 카메라로부터 발생하는 노이즈나 극단치 (outlier)의 영향을 줄이기 위해 그래디언트 필드에서 초기 방향을 기준으로 노이즈와 극단치를 제거한 후 방향을 구하는 방법을 사용하였다. 실험에서는 모바일 카메라를 이용하여 획득한 지문영상으로 지문영역 추출 및 융선방향 정보 추출에 대한 평가를 했다. 지문영역 추출 알고리즘 평가를 위해 600장의 수동 구분된 지문영상을 사용하였고 융선방향 정보 추출은 지문 인식성능으로 비교 평가 하였다. Fingerprint segmentation and ridge orientation estimation algorithms with images from a mobile camera are proposed. The fingerprint images from a mobile camera are quite different from those from conventional sensor, called touch based sensor such as optical, capacitive, and thermal. For example, the images from a mobile camera are colored and the backgrounds or non-finger regions are very erratic depending on how the image capture time and place. Also the contrast between ridge and valley of a mobile camera image are lower than that of touch based sensor image. To segment fingerprint region, we first detect the initial region using color information and texture information. The LUT (Look Up Table) is used to model the color distribution of fingerprint images using manually segmented images and frequency information is extracted to discriminate between in focused fingerprint regions and out of focused background regions. With the detected initial region, the region growing algerian is executed to segment final fingerprint region. In fingerprint orientation estimation, the problem of gradient based method is very sensitive to outlier that occurred by scar and camera noise. To solve this problem, we propose a robust regression method that removes the outlier iteratively and effectively. In the experiments, we evaluated the result of the proposed fingerprint segmentation algerian using 600 manually segmented images and compared the orientation algorithms in terms of recognition accuracy.

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