• Journal of Chest Surgery
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• v.32 no.2
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• pp.124-129
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• 1999

Background: Ventricular septal defect(VSD) that causes pulmonary hypertension increase right ventricular workload. Echocardiographic assessment of right ventricular systolic time interval (RVSTI) has been used to predict pulmonary artery pressure in various cardiopulmonary diseases. This study was undertaken in infants with simple VSD to observe the alteration of the right ventricular workload through the changes of RVSTI after repair of VSD. Material and Method: We evaluated heart rate, the ratio of the left atrium/aortic root diameter (LA/Ao), right ventricular pre-ejection period(RVPEP), right ventricular ejection time(RVET), and its ratio(RVPEP/RVET) as a predictor of right ventricular workload in 12 children with simple VSD. These were measured three times at the preoperative period, at the 3 month and between 6 month and 1 year(average 9.5${\pm}$1.8month) after repair of VSD by M-mode & Doppler echocardiograph from the pulmonic valve echogram. Result: Heart rate was decreased significantly after repair(137.1${\pm}$13.7 vs 114.4${\pm}$21.1 and 104.1${\pm}$10.2, p<0.01). LA/Ao ratio was decreased significantly after repair(1.71${\pm}$0.32 vs 1.47${\pm}$0.33 and 1.39${\pm}$0.23, p<0.05). RVPEP/RVET were decreased after repair (0.38${\pm}$0.09 vs 0.32${\pm}$0.08 and 0.29${\pm}$0.09, p<0.01). Heart rate corrected RVPEP/RVET were significantly decreased only after 6 months(0.32${\pm}$0.03 vs 0.30${\pm}$0.05 and 0.28${\pm}$0.06, p<0.05). Conclusion: We found elevated right ventricular workload was progressively decreased until more than 6 months after repair and the RVSTI may serve a useful guide in postoperative care for children with VSD.

• Journal of the Korean housing association
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• v.13 no.2
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• pp.7-14
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• 2002

The deteriorated high-rise apartments make a social problem in now days. As a result, an new alternative plan for deteriorated high-rise apartments such as the remodeling concept must be considered. This study aims to develop the remodeling items which is the guide lines when remodeling of the apartment will be conducted. Thorough the previous case studies of maintenance and repair status of the deteriorated apartments in Seoul, the analysis of the period of repair and improvement and the degree of request far remodeling items, reasonable guidelines for selection of remodeling items were developed. According to the ages of apartments As a result of the study, basic guidelines fur selection of remodeling items were proposed.

• Journal of Korean Society for Quality Management
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• v.21 no.2
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• pp.102-108
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• 1993

The purpose of burn-in is to eliminate the early failures of the products before they are delivered for customer use. Therefore burn-in should he continued until one is reasonally sure that all the weak items have failed, thus leaving the remaining items in a healthy state of reliability. From this point of view, burn-in time dependent costs such as a cost per product per burn-in time, and cost of repair of the product per failure occurred during burn-in time will he increased. Conversely, the cost of field repair of the product per failure occurred during the guarantee period will be decreased since the early failure of the product is fully eliminated during burn-in. Hence, this paper intend to determine optimal burn-in time which minimize the total of above costs associated with burn-in.

• Journal of Chest Surgery
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• v.19 no.2
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• pp.288-294
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• 1986

During the period from Mar. 1983 to Feb. 1986, 22 patients with vascular trauma were treated at Capital Armed General Hospital. 1] 11 patients had arterial injury alone, 6 patients had venous injury alone, and 5 patients had both arterial and venous injuries. 2] The mechanism of injury in these 22 patients was 7 penetrating non-gun shot wounds, 5 blast fragments injuries, 4 iatrogenic injuries, 4 blunt injuries, 2 gun shot wounds. 3] The method of 16 arterial repair was 5 autogenous saphenous vein graft, 8 synthetic vascular graft, 1 end to end anastomosis, 2 lateral suture. Midterm patency of 16 repairs was 100% within 1 months. 4] The method of 11 venous repair was 1 autogenous saphenous vein graft, 2 onlay vein patch, 2 ligation, 1 lateral suture. The thrombotic obstructions occurred in 4 repairs [36.4%], but they were resolved somewhat with heparinization. 5] Uncommon cases of false aneurysm of internal carotid artery and laceration of retrohepatic inferior vena cava were summarized.

• Journal of Chest Surgery
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• v.24 no.6
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• pp.560-569
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• 1991

The surgical management of symptomatic tetralogy of Fallot in infants is debatable. From November 1986 to August 1990, 21 infants under 10 kg of the body weight with tetralogy of Fallot underwent primary repair. Mean body weight was 8.6$\pm$1.40kg. All the patient were clubbing and there were cyanotic except for 1 patient. Transannular patch was laid down in 8 patients. Right ventricular outflow patch was used with Goretex but pericardial patch was utilized in 3 patients at the initial period of operation. Incidence of the complications following total correction of tetralogy of Fallot was more frequent in the patients placed with transannular patch compared to the patients with right ventricular outflow tract patch. Two deaths occurred in the 21 patients, Hospital mortality was 9.4%, but there were no operative deaths in the patients who transannular patch was laid down. Causes of deaths were low cardiac output.

• Journal of Chest Surgery
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• v.24 no.6
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• pp.625-630
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• 1991

From April 1990 through June 1990, three patients underwent subclavian flap aortoplasty for relief of the coarctation of the aorta. The age of the patients were 13 days, 7 months and 39 months and their weights were 3.3kg, 6.5kg, and 11kg, respectively. Two patients had persistence of the ductus arteriosus and all patients had associated intracardiac anomalies. We used the technique devised by Mendonca, namely, repair of the coarctation of the aorta using the subclavian artery as a flap and preservation of the arterial blood flow to the left arm. In one patient with long narrowing of isthmus, significant residual pressure gradient was remained by this technique and we added patch aortoplasty. There were no hospital deaths and follow-up over a one year period shows all patients in good condition.

• Journal of Chest Surgery
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• v.18 no.2
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• pp.250-257
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• 1985

Despite low mortality and excellent long-term results after repair of Tetralogy of Fallot, certain associated anomaly such as single pulmonary artery continues to be told to have a high operative mortality and morbidity, and there is still some debate on appropriate surgical intervention. During the 4 year period from 1981 to 1984, surgical repair was performed on 5 patients with tetralogy of Fallot and congenital [4 cases] or acquired [1 case] absence of left pulmonary artery. Previous left pneumonectomy had been performed in the patient with acquired absence of a pulmonary artery. Transannular patch or RVOT patch alone with or without pulmonic valvotomy was used with some modifications to reduce pulmonic insufficiency in individual patient. In contrast with previous reports, all patients survived operation and have exhibited marked symptomatic improvement without pulmonic valve insertion nor valved conduit.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.350-353
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• 2003

Navy surface vessels require pier services such as emergency repair, oil supply, fm loading/unloading, crane, standby readiness, normal repair, gun arrangement, ammunition loading, and food loading during the period in port. The purpose of this study is to establish efficient berth allocation plan for navy surface vessels in home port under the limited resources of piers and equipments. The study suggests Mixed Integer Programing (MIP) model for bath allocation problem, considering precedence relationships among services. For a effective analysis, the model is implemented by ILOG OPL(Optimization Programming Language) Studio 3.1 and ILOG Cplex 7.0. The results of the model show reduction of berth shifts and increasement of service benefits. And thus, it would be a possibility of contribution in the improvement of fleet readiness.

• Communications for Statistical Applications and Methods
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• v.6 no.1
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• pp.99-106
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• 1999

This paper considers an imperfect repair model for which the repairable system is maintained preventively at periodic times and is replaced by a new system when a predetermined number of preventive maintenance has been applied. our main objective of this is to determine the optimal number of preventive maintenances before the system is replaced and the optimal length of interval between two consecutive preventive maintenances under a new repair model which is referred to as an ineffective preventive maintenance. Such a model assumes a periodic preventive maintenance in which the system is effectively maintained with a certain probability. Otherwise the system is not improved at all after each maintenance and thus the failure rate remains the same as before. The criteria to determine the optimal number of preventive maintenances and length of period is the expected cost rate per unit time for an infinite time span. We give the explicit expressions for the expected cost rate per unit time. Some numerical examples are presented for illustrative purposes.

• Journal of Chest Surgery
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• v.28 no.6
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• pp.610-618
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• 1995

Three neonates with interrupted aortic arch with VSD underwent one stage repair using revised technique of cardiopulmonary bypass with short period of circulatory arrest. A left posterolateral thoracotomy was made to permit mobilization of the descending aorta and placement of polytetrafluoroethylene[PTFE graft for distal aortic perfusion. Then the patient was placed in the supine position and a median sternotomy was performed to permit the proximal dissection, VSD repair, and direct anastomosis between the ascending aorta and descending aorta. This technique has advantages to facilitate direct anastomosis between the ascending aorta and the descending aorta, to lessen circulatory arrest time, and to prevent dangerous laceration and post-operative narrowing of the thin small ascending aorta at cannulation site. There was no operative mortality but postoperative stenosis developed in one case which was relieved with balloon aortoplasty.