• Journal of Chest Surgery
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• v.21 no.4
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• pp.630-640
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• 1988

We clinically evaluated 222 cases of ventricular septal defect which we experienced at Department of Thoracic and Cardiovascular Surgery, Pusan National University Hospital between July 1981 and March 1988. These patients were occupied 46.2% of all congenital heart disease operated on its same period. Of 222 cases, 132 patients were male and 90 patients were female. Their age distribution ranged from 8 months to 34 years of age and their mean age was 10.3 years. Among these patients, 86 patients had associated cardiac anomalies, which were patent foramen ovale 43 cases[19.5%], Atrial septal defect 18 cases[8.1%], patent ductus arteriosus 8 cases[3.6%], aortic insufficiency 7 cases[3.2%], infundibular pulmonary stenosis 5 cases[2.3%] and etc. There was statistically significant correlationship between VSD size and Qp/Qs, Rp/Rs, Pp/Ps respectively. All cases were operated under cardiopulmonary bypass and 157 patients[70.7%] would be corrected through right atrial approach. 158 patients[71.2%] underwent closure of ventricular septal defect with primary closure and the remained patients[28.8%] with patch closure. In anatomical classification by Kirklin, type I constituted 23.4%, type II 73.4%, type III 0.5%, type I and type II 1.4%, and type II and type III 1.4%. Important postoperative EGG changes were noted in 57 cases[25.7%] and incomplete right bundle branch block was most common[12.6%]. 54 patients[24.3%] developed minor and major postoperative complications and 9 patients died of several complications and overall operative mortality was 4.1%.

• Journal of Chest Surgery
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• v.27 no.8
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• pp.650-655
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• 1994

The author analyzed 99patients with VSD weighting less than 10kg of body weight who underwent surgical correction from 1981 to 1992 at cardiovascular department of Hanyang University hospital. Patients occupied 29.3% of total cases who were underwent surgical corrections for congenital heart diseases during that time. Of the 99 patients, 51 patients were male [52%] and 48 patients[48%] were female. Age ranged from 28 days to 36 months with mean age of 13.6 months. Mean body weight was 7.53kg. According to Kirklin`s anatomical classification, type II defect was most common [61.6%]. Associated anomaly was found in 48 patients [48.5%]. Patent foramen ovale was most commonly associated cardiac anomaly [14.1%] and followed by atrial septal defect [12.1%], patent ductus arteriosus [10.1%]. Cardiac catheterization data were analyzed. The most common range of Qp/Qs, Rp/Rs, Pp/Ps were above 3.0, 0.1 - 0.25, and above 0.75 respectively. Among the indications of surgical correction, there were pulmonary hypertention in 69 patients, congestive heart failure in 44 patients, frequent respiratory infection in 47 patients, growth retardation in 33 patients. The most common surgical approach and method for VSD closure were right atriotomy[48.3%] and dacron patch closure[93.3%]. Complication rate was 13.1% [13 cases], and overall mortality was 17.1% [17 cases]. The cause of death consisted of low cardiac output syndrome[11 cases], acute renal failure[3 cases], sepsis[2 cases] and pulmonary insufficiency[1 case] in order of frequency.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.1
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• pp.426-445
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• 2012

Conventional rate control (RC) schemes for H.264 video coding usually regulate output bit rate to match channel bandwidth by adjusting quantization parameter (QP) at fixed full frame rate, and the passive frame skipping to avoid buffer overflow usually occurs when scene changes or high motions exist in video sequences especially at low bit rate, which degrades spatial-temporal quality and causes jerky effect. In this paper, an active content adaptive frame skipping scheme is proposed instead of passive methods, which skips subjectively trivial frames by structural similarity (SSIM) measurement between the original frame and the interpolated frame via motion vector (MV) copy scheme. The saved bits from skipped frames are allocated to coded key ones to enhance their spatial quality, and the skipped frames are well recovered based on MV copy scheme from adjacent key ones at the decoder side to maintain constant frame rate. Experimental results show that the proposed active SSIM-based frameskip scheme acquires better and more consistent spatial-temporal quality both in objective (PSNR) and subjective (SSIM) sense with low complexity compared to classic fixed frame rate control method JVT-G012 and prior objective metric based frameskip method.

• Journal of Multimedia Information System
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• v.8 no.3
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• pp.147-158
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• 2021

Versatile Video Coding (VVC) is the latest video coding standard developed by Joint Video Exploration Team (JVET). In VVC, the quadtree plus multi-type tree (QT+MTT) structure of coding unit (CU) partition is adopted, and its computational complexity is considerably high due to the brute-force search for recursive rate-distortion (RD) optimization. In this paper, we aim to reduce the time complexity of inter-picture prediction mode since the inter prediction accounts for a large portion of the total encoding time. The problem can be defined as classifying the split mode of each CU. To classify the split mode effectively, a novel convolutional neural network (CNN) called multi-level tree (MLT-CNN) architecture is introduced. For boosting classification performance, we utilize additional information including inter-picture information while training the CNN. The overall algorithm including the MLT-CNN inference process is implemented on VVC Test Model (VTM) 11.0. The CUs of size 128×128 can be the inputs of the CNN. The sequences are encoded at the random access (RA) configuration with five QP values {22, 27, 32, 37, 42}. The experimental results show that the proposed algorithm can reduce the computational complexity by 11.53% on average, and 26.14% for the maximum with an average 1.01% of the increase in Bjøntegaard delta bit rate (BDBR). Especially, the proposed method shows higher performance on the sequences of the A and B classes, reducing 9.81%~26.14% of encoding time with 0.95%~3.28% of the BDBR increase.

• The Journal of Korea Robotics Society
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• v.18 no.3
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• pp.241-250
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• 2023

This paper describes the posture stabilization control of a bipedal transformer robot being developed for military use. An inverted pendulum model with a rectangular that considers the robot's inertia is proposed, and a posture stabilization moment that can maintain the body tilt angle is derived by applying disturbance observer and state feedback control. In addition, vertical force and posture stabilization moments that can maintain the body height and balance are derived through QP optimization to obtain the necessary torques and vertical force for each foot. The roll and pitch angles of the IMU sensor attached to the robot's feet are reflected in the ankle joint to enable flexible adaptation to changes in ground inclination. Finally, the effectiveness of the proposed algorithm in posture stabilization is verified by comparing and analyzing the difference in body tilt angle due to disturbances and ground inclination changes with and without algorithm application, using Gazebo dynamic simulation and a down-scale test platform.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.1500-1503
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• 2008

H.264와 같은 고압축 비디오처리 기법의 등장으로 기존의 MPEG2와 같은 비디오 압축에서 H.264로의 비디오 트랜스코딩이 증가되고 있지만, 고압축 비디오 콘텐츠의 온라인과 오프라인에서 불법배포는 현재 문제가 되고 있다. 본 논문에서는 다이렉트쇼 환경 기반에서 고압축과 저작권 보호를 위한 비디오 트랜스 코딩과 워터마킹을 구현한다. 제안한 방법은 다이렉트쇼의 필터를 이용하여 MPG,WMV를 H.264로 비디오 트랜스코딩을 하고 이와 함께 비디오의 공간영역 특성을 이용하여 저작권 보호를 위한 강인한 워터마킹을 구현한다. 실험 결과 MPG,WMV를 H.264로 트랜스코딩에서 H.264의 QP(Quantization parameter)를 15로 하고 화면간 반복을 10프레임으로 하였을 경우 저작권 보호를 위하여 삽입된 워터마크는 평균 99% 검출됨을 확인하였고, 또한 트랜스코딩중 워터마크삽입에 따른 시간지연은 전체 트랜스코딩시간의 5.7%가 됨을 확인할 수 있었다. 제안한 방법은 저작권 삽입 기능가지는 트랜스코딩 소프트웨어를 필요로 하는 Digital TV방송, IPTV, DVD 사업에 사용 될 수 있을 것이다.

• Journal of Chest Surgery
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• v.14 no.1
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• pp.49-59
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• 1981

This is one case report of surgically treated partial atrioventricular canal. The 22 year-old male patient had no definitive history of frequent respiratory infection and cyanosis in his early childhood. Since his age of 7 years, dyspnea was manifested on exertion. First appearance of congestive heart failure was at his age of 16 years old. The physical examination revealed that the neck veins were distended and heaving of precordium. A thrill was palpable on the left 3rd-4th intercostal space extending from the sternal border toward the apex and Grade IV/VI systolic ejection murmur was audible on it. Neither cyanosis nor clubbing was noted. Liver was palpable about 5 finger breadths. Chest X-ray revealed increased pulmonary vascularity and severe cardiomegaly (C-T ratio = 74%). EKG revealed LAD, clockwise rotation, LVH and trifascicular block. Echocardiogram showed paradoxical ventricular septal movement, narrowed left ventricular outflow tract and abnormal diastolic movement of the anterior leaflet of mitral valve. Right heart catheterization resulted in large left to right shunt (Qp : Qs = 5.7: 1), ASD and moderate pulfllonary hypertension. Finally, left ventriculogram revealed typical goose neck appearance of left ventrlcalar outflow tract. On Oct. 10, 1980, open heart surgery was performed. Operative findings were: 1. Large primum defect ($6{\times}5$ Cm in diameter) 2. Cleft on the anterior leaflet of mitral valve. 3. The upper portion of ventricular septum was descent but no interventricular communication. 4. Downward attachment of the atrioventricular valves on the ventricular muscular septum. 5. Medium sized secumdum defect ($2{\times}1$ Cm in diameter). The cleft was repaired with 4 interrupted sutures. The primum defect was closed with Teflon patch and the secundum defect was closed with direct suture closure. Postoperatively atrial flutter-fibrillation in EKG and Grade U/VI apical systolic murmur were found. The postoperative course was uneventful and discharged on 29th postoperative day in good general conditions.

• Journal of Chest Surgery
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• v.24 no.9
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• pp.853-860
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• 1991

A clinical study on 139 cases of operated PDA was performed during period from Aug. 1982 to Apr. 1991 at the Dept. of Thoracic and Cardiovascular Surgery of Chonbuk National University Hospital. The following results are obtained. 1. The 35 males and 104 females ranged in age from 6 months to 40 years. [mean 10.2 yrs. ] 2. Chief complaints of the patients were frequent URI in 50%, dyspnea on exertion in 31.2%, palpitation in 11.1%, and no subjective symptoms in 28.78% 3. On auscultation, continuous machinery murmur heard in 79.86% and systolic murmur in 20.14%. 4. Radiologic findings of chest P-A showed increased density of pulmonary vascularity in 80.58%, cardiomegaly in 61.87%, and within normal limit in 19.42% of the patients. 5. The signs of LVH[44.4%], RVH[17.4%], BVH[7.6%] were noted on the EKC. 6. Cardiac catheterizations were performed in 114 patients. The mean Qp/Qs was 2.65 and the mean Pp /Ps was 0.41 and the mean systolic pulmonary artery pressure was 46.6 mmHg. 7. Operative methods were as followed: The 130 cases[93.52%] of ligation and 3 cases[2.16%] of division & suture for PDA were performed through the left posterolateral thoracotomy. And the remained cases were managed under the cardiopulmonary bypass. 8. Operative complications were hoarseness in 8 cases, atelectasis in 6 cases, intraoperative ductal rupture under the left thoracotomy approach 2 cases, recannalization 1 case and others in 3 cases. 9. One patient died due to ductal rupture intraoperatively and the overall mortality was 0.7%.

• Journal of Chest Surgery
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• v.21 no.6
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• pp.1117-1123
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• 1988

Prolapse of the aortic valve is the main cause of insufficiency of the aortic valve as a complication of ventricular septal defect. Aortic insufficiency gets worse by the progress of prolapse of aortic valve due to lack of support of the valve and the hemodynamic effect of blood flow through the ventricular septal defect. This produces typical clinical picture, that may be serious and threatening when it is untreated. Type and timing for the surgical treatment of the ventricular septal defect with aortic insufficiency is considered. Among 113 ventricular septal defect, 9 patients of ventricular septal defect with associated aortic insufficiency were experienced from June. 1983 to June 1988 at the Department of Thoracic and Cardiovascular Surgery, Chon-Buk University Hospital. Male was 6 patients and female was 3 patients. Ages were from 7 years to 24years. 5 patients were from 10 to 19 years age. 3 patients were below 10 years age. The ratio of pulmonary blood flow to systemic f low [Qp/Qs] was 1.53 and in pulmonary vascular resistance, normal or slight increase was 7 patients, moderate 1 patient, and severe 1 patient. Ventricular septal defect was subpulmonic in 5 patients and infracristal in 4 patients. Prolapse of right coronary cusp was 7 patients, right and non coronary cusp 1 patient and non coronary cusp 1 patient. Teflon patch closure of ventricular septal defect was undertaken in 3 patients and primary closure in 1 patient. Among the 4 patients of defect closure alone, one patient performed valve replacement 7 months later due to progressive regurgitation and cardiac failure and the result was good. The other 3 patients were good result. Closure of ventricular septal defect and aortic valvuloplasty performed in 4 patients. 2 patients of these required valve replacement for the sudden intractable cardiac failure and died due to low cardiac output. The cause of intractable cardiac failure was tearing of repaired valve at the fixed site. The other 2 patients were good result. Closure of ventricular septal defect and valve replacement performed in 1 patient with good result.

• Journal of Chest Surgery
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• v.18 no.2
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• pp.165-173
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• 1985

A clinical analysis was performed n 706 uses of patent ductus arteriosus experienced at Department of Thoracic and Cardiovascular Surgery, Seoul National University Hospital during 27 years period from 1958 to 1984. Of the 706 patients of PDA, 244 patients were male and 462 patients were female and ages ranged from 2 months to 53 years old with the average age of 8.5 years. The chief complaints on admission were dyspnea on exertion and frequent URI in 58.9%, non specific symptoms such as palpitation and easy fatigability in 9.7%, symptoms of CHF in 2.0% and no subjective symptoms in 29.4%. On auscultation of heart, continuous machinery murmurs were heard in 82% and only systolic murmurs were heard in 18% of patients. On simple chest PA of patients, cardiomegalies were detected in 78% and there were increased pulmonary vascularities in 93% of patients. EKG findings were as followed; LVH 56.9%, BVH 12.6%, RVH 2.9% and WNL 27.6%. Cardiac Catheterizations were performed in 512 patients and mean Qp/Qs was 2.56 and mean systolic pulmonary artery pressure was 45mmHg. Operation methods were as followed; in patients in whom operations were performed on PDA only, ligation 94.3%, division 3.7% and ligation [0.5%] or trans-pulmonary artery suture closure [1.5%] under cardiopulmonary bypass 2.0% and in patients in whom operations were performed with associated anomalies, ligation 17.6%, division 2.4%, and ligation [44.7%] or trans-pulmonary artery suture closure [35.3%] under cardiopulmonary bypass 80%. 52 postoperative complications [8.4%] were developed in 42 patients [6.8%] and its were as followed; permanent or transient hoarseness 16 [2.6%], intraoperative rupture of PDA 8 [1.3%], recannalization 6 [1.[%], operative death 5 [0.8%], late death 4 [0.6%] and other miscellaneous complications 13 [2.1%]. 140 associated cardiac anomalies [19.8%] were found in 105 patients [14.9%] and its were as followed; VSD 68 [9.6%], COA 15 [2.1%], Subaortic discrete membrane 7 [0.9%], ASD 6 [0.8%], TOF 5 [0.7%] and other miscellaneous and