흉부손상의 임상적 고찰: 473예

곽영태,유세영 慶熙大學校 醫科大學 1981 慶熙 醫大 論文集 Vol.6 No.1

다층퍼셉트론의 오류역전파 학습과 계층별 학습의 비교 분석

곽영태 한국정보통신학회 2003 한국정보통신학회논문지 Vol.7 No.5

본 논문은 MLP의 학습 방법으로 사용되는 EBP학습, Cross Entropy함수, 계층별 학습을 소개하고, 필기체 숫자인식 문제를 대상으로 각 학습 방법의 장단점을 비교한다. 실험 결과, EBP학습은 학습 초기에 학습 속도가 다른 학습 방법에 비해 느리지만, 일반화 성능이 좋다. 또한, EBP학습의 단점을 보안한 Cross Entropy 함수는 학습 속도가 EBP학습보다 빠르다. 그러나, 출력층의 오차 신호가 목표 벡터에 대해 선형적으로 학습하기 때문에, 일반화 성능이 EBP학습보다 낮다. 그리고, 계층별 학습은 학습 초기에, 학습 속도가 가장 빠르다. 그러나, 일정한 시간 후, 더 이상 학습이 진행되지 않기 때문에, 일반화 성능이 가장 낮은 결과를 얻었다. 따라서, 본 논문은 MLP를 응용하고자 할 때, 학습 방법의 선택 기준을 제시한다. This paper surveys the EBP(Error Back Propagation) learning, the Cross Entropy function and the LBL(Layer By Layer) learning, which are used for learning the MLP(Multi Layer Perceptrons). We compare the merits and demerits of each learning method in the handwritten digit recognition. Although the speed of EBP learning is slower than other learning methods in the initial learning process, its generalization capability is better. Also, the speed of Cross Entropy function that makes up for the weak points of EBP learning is faster than that of EBP learning. But its generalization capability is worse because the error signal of the output layer trains the target vector linearly. The speed of LBL learning is the fastest speed among the other learning methods in the initial learning process. However, it can't train for more after a certain time, it has the lowest generalization capability. Therefore, this paper proposes the standard of selecting the learning method when we apply the MLP.

기관 재건술 후 발생한 기관 무명동맥루

곽영태,신원선,맹대현,이신영,김수철,박주철,김동원 대한흉부심장혈관외과학회 1996 Journal of Chest Surgery Vol.29 No.11

Tracheoinnominate artery fistula is a rare but a catastrophic complication after tacheostomy or tracheal reconstruction. We experienced one case of tracheoinnominate artery fistula after tracheal reconstruction. The patient was a 11 year old girl with cerebral arteriovenous malformation who maintained tracheostomy for 6 months before undergoing tracheal reconstruction. She complained of dyspnea and paroxysmal cough 5 months after tracheostomy and was diagnosed as tracheal stenosis. We performed 4cm of tracheal resection and end to end anastomosis. Three days after tracheal reconstruction, massive bleeding occurred through the intubation tube. She underwent emergency reoperation of repair the innominate artery with 5-0 Prolene and re-reconstruction of trachea. The patient died of bleeding 3 days after the reoperation.

복부 대동맥류 수술의 임상적 고찰

곽영태,임상현,이삭,유경종,장병철,강면식,홍유선 대한흉부외과학회 2003 Journal of Chest Surgery Vol.36 No.4

배경: 복부 대동맥류 수술은 높은 사망률을 나타낸다. 저자들은 지난 11년간의 복부대동맥류 수술결과를 토대로 앞으로의 치료에 도움을 받고자 연구를 시행하였다. 대상 및 방법: 1990년 1월부터 2000년 12월까지 연세대학교 흉부외과에서 복부 대동맥류로 수술 받은 환자 48명을 대상으로 하였는데, 평균 나이는 62.8±12.7 (27~85)세였고 남자가 40명, 여자가 8명이었다. 48명의 환자들 중 9명은 대동맥류가 파열되었었고, 파열되지 않았던 환자들의 대동맥류 평균 직경은 8.8±2.4 (5.0~15) cm였다. 결과: 48명의 환자들 중 6명이 조기에 사망하여 조기 사망률은 12.5%였다. 수술 전 동맥류의 파열이 있었던 9명의 환자 중 3명이 사망했고(33.3%), 동맥류의 파열이 없었던 환자들은 39명 중 3명이 사망하였다(7.7%). 수술 전에 확인한 여러 변수들 중 나이(p=0.00690), 수술 전 BUN 수치(p=0.0278), 당뇨(p=0.038) 등이 수술 사망의 위험인자로 확인되었다. 퇴원한 42명의 환자들 중 40명에서 추적이 되어 추적률은 95.2%였으며 평균 추적 기간은 3.6±0.2 (0.3~10.7)년이었다. 추적 기간 동안 5명의 환자가 사망하였으며(만기 사망률=11.9%), Kaplan-Meier 생존 분석에 의한 5년과 10년 생존율은 각각 81.7±7.6%, 81.7±7.6%였고, 인조혈관과 관련된 사건이 일어날 확률은 3.53%/환자-년이었다. 결론: 파열된 복부 대동맥류의 수술 사망률은 파열되지 않은 경우에 비해 높기에 조기에 복부 대동맥류를 제거하는 것이 수술 사망률을 낮출 수 있으리라 생각한다.

Stabilization of extra rich CH4/O2 flame in a two-section porous medium and the thermal partial oxidation characteristics thereof

곽영태,이대근,고창복 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.10

Fuel-rich CH 4 /O 2 flames in a two-section porous medium burner were experimentally investigated for its application to the production of high concentration H 2 /CO syngas. The burner was made up of two axially-stacked silicon carbide foams having different pore sizes. Various flame behaviors, such as stable flame, flashback and blowout, were observed and, for the stable flame, temperature distributions and reformate compositions were measured. Results showed that the flame was stable in a sideway V-shape region on the domain of equivalence ratio and filtration velocity. Especially, it was found that the maximum equivalence ratio of the upper stable region was larger than the fuel-rich flammability limit showing characteristics of submerged combustion in porous media, which made the reaction closer to the stoichiometric partial oxidation. The reformate composition was measured for various conditions and maximum mole fraction of H 2 and CO was 55.5 % and 28.0 % in dry basis being much higher than the air oxidant case. From these results, the reforming performance such as CH 4 conversion, selectivity and yield of H 2 , CO, and energy conversion efficiency were evaluated. The equilibrium and the adiabatic planar flame were simulated as references to investigate the characteristics of partial oxidation reforming. The results may indicate that the porous media burner can be practically applied in producing high concentration H 2 /CO syngas, if it is designed to ensure minimum heat loss and enough residence time.

필리핀 돼지고기 시장 분석 및 수출 전망

곽영태 한국축산식품학회 2006 한국축산식품학회지 Vol.26 No.4

한 일 낙농경영의 구조변화에 관한 비교분석

곽영태,류제창 ( Young Tae Kwak,Je Chang Ryu ) 한국축산경영학회 1994 韓國畜産經營學會誌 Vol.10 No.1

Stapler 를 사용한 폐절제술에 대한 임상적 고찰

곽영태 대한흉부심장혈관외과학회 1983 Journal of Chest Surgery (J Chest Surg) Vol.16 No.2

A comparative study was taken for pulmonary resection between group stapler used and not used. 1 ] There was no bronchopleural fistula in 22 cases of stapler used group, but in 4.5% in not used group. 2] The postoperative amount of fluid and air leakage through the chest tube were lesser in stapler used group. 3] The operating time was shorter in stapler used group because of lesser dissection of hilar structure.

혈장세포 육아종[보고 1예]

곽영태,박주철,유세영,Kwack, Yeong-Tae,Park, Ju-Cheol,Yoo, Seh-Young 대한흉부심장혈관외과학회 1981 Journal of Chest Surgery (J Chest Surg) Vol.14 No.3

A 31-year-old female visited O.P.D. of internal medicine, Kyung Hee Medical center, with the chief complaint of generalized weakness and headache. She took a routine chest P-A and there was a 6.5 x 7.5 cm sized round mass in the right middle lung field. She admitted to the Dept. of Thoracic and Cardiovascular Surgery under the impression of malignant bronchogenic carcinoma with the remit of bronchoscopy and sputum cytology and tomogram. Middle and lower lobectomy of right lung was performed and postoperative surgical biopsy revealed out the plasma cell granuloma. The plasma cell granuloma may occur as a solitary nodule in the lung or be associated with systemic disease, plasma protein imbalance, or nonspecific local inflammatory reaction . More than two third of the reported patients were less than 30 year of age. Grossly the lesion appears reddish-brown and microscopic features include pallisade or a cartwheel distribution of plasma cells with Russel bodies and amyloid. Local excision or lobectomy has been curative in most cases.

동맥관 개존증의 임상적 고찰

곽영태 대한흉부심장혈관외과학회 1984 Journal of Chest Surgery (J Chest Surg) Vol.17 No.4

With the ligation of patent ductus arteriosus by Gross in 1938, surgeons first entered the field of congenital heart disease. Interruption of a ductus is one of the most satisfactory and curative operations in the field of surgery for congenital heart disease. 27 cases of isolated patent ductus arteriosus were operated from Jan. 1978 to July 1984 at the Department of Thoracic & Cardiovascular Surgery in Kyung-Hee University Hospital. Retrospective clinical analysis of these patients were: 1. Sex ratio, female: male, was 2:1. 2. Mean age at operation was 9.85\ulcorner.58 years. The youngest patient was a 23 month-old girl and the oldest one was a 24 year-old male. 3. More than half of the patients had less than 50 percentile of growth retardation. 4. Chief complaints of the patients were frequent URI [52%], dyspnea on exertion [33%], generalized weakness [22%], palpitation [7%], but 7 patients [26%] had no subjective symptoms. 5. Continuous machinery murmur could be heard at the 2nd or 3rd intercostal space on the left sternal border in 22 patients [81%]. The other S patients made systolic murmur with accentuation of the second heart sound and those were associated with pulmonary hypertension. 6. Radiologic findings of Chest P-A were cardiac enlargement in 15 patients [55%], enlargement of pulmonary conus and/or increasing density of pulmonary vascularity in 20 patients [74%]. 7. Electrocardiographic findings of the patients were within normal limit in 13 patients [48%], LVH in 4 patients [15%], biventricular hypertrophy in 3 patients [11%]. 8; echocardiogram was obtained from 11 patients. Ductus was directly visualized in 7 patients. Left atrial enlargement is the secondary change of left to right shunt, 10 patients had LA/Ao ratio more than 1.2. 9. Cardiac catheterization performed in 25 patients. The mean value of the results were:SO2[PA-RV]= 14.72\ulcorner6.01%, Qp/Qs=2.22\ulcorner.80, peak systolic pulmonary arterial pressure=48.28\ulcorner1.60 mmHg. 10. 26 patients were operated through the left posterolateral thoracotomy: closure of ductus by double ligation in 14 cases, triple ligation in 5 cases, and division with suture in 8 cases. One patient suffer from aneurysmal rupture of main pulmonary artery, endocarditis, hemopericardium was treated with cardiopulmonary bypass via median sternotomy and closure of ductus through the ruptured main pulmonary artery. 11.There was no death associated with the operation, but 3 cases were experienced with intraoperative rupture around the ductus resulting in massive bleeding. The other complications were transient hoarseness in one patient, atelectasis in left lower lobe in 3 patients, and postoperative systemic hypertension in 4 patients with unknown etiology. 12. Pulse pressure was reduced, 11.47+5.92 mmHg, postoperatively, as compare to preoperative status. 13. Intraoperative wedge lung biopsy from lingular segment for the evaluation of the pulmonary vascular disease was taken in S patients with severe pulmonary hypertension. The result was Heath-Edward grade I in one case, grade II in two cases, and grade III in two cases.