• Journal of Chest Surgery
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• v.33 no.6
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• pp.476-486
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• 2000

Background: Pulmonary atresia with intact ventricular septum(PA/IVS) is an anatomically heterogenous anomaly with a variety of surgical strategies possible. The purpose of the study is to evaluate the influence of right ventricular size on the early and midterm results of surgical repair of PA/IVS. Material and method: Medical records of 20 consecutive patients with PA/IVS operated on between January 1993 and August 1999 were retrospectively reviewed. There were 12 boys and 8 girls whose ages ranged from 2 days to 14.5 months (median 6 days). Their body weight ranged from 2.52kg to 9.35 kg(median 3.18kg). The preoperative Z-value of the diameter of the tricuspid valve(T-valve) was less than or -4 in 5 patients, between -4 and -2 in 1, between -2 and 0 in 7, between 0 and 2 in 6, and greater than or 2 in 1. All patients who had z-value of tricuspid valve greater than -2.05 were attempted biventricular repair(n=15) and all patients who had it smaller than -4.4 underwent systemic-pulmonary shunt operation only(n=3) or bidirectinal cavopulmonary shunt with right ventricular reconstruction(n=2). Result: Two early deaths(2/20, 10%) occurred. Both were infants who underwent transannular patch with shunt. One of these two had huge right ventricle(Z-value of tricuspid valve = 5). There were 2 late non-cardiac deaths 3 and 7 months after operations respectively. Follow-up was completed in all children at a mean of 35.3 months(range, 5 to 54 months). 10 of 11 survivors who underwent transannular patch or valvotomy with or without shunt procedure were in NYHA functional class I even though some of them had small interatrial communication or patent shunt. All three patients who had shunt procedure only at initial palliation completed Fontan procedures with no death. Two patients who underwent right ventricular outflow reconstruction with bidirectional cavopulmonary shunt were also in good condition. Conclusion: The transanular RVOT patch or valvotomy with or without systemic-pumonary shunt as an initial palliative procedure to achieve biventricular repair for the patients who had neither too small nor too large right ventricle(-2.05$\leq$Z-value of T-value of T-valve$\leq$2) could be performed at low operative risk(1/14 7.1%). Systemic-pulmonary shunt procedure and bidirectional cavopulmonary shunt procedure for the patients who had small right ventricle(Z-value of T-valve$\leq$4.4) could be also performed with low risk. But a patient with huge right atrium and ventricle(Z-value of t-valve=5) had poor operative result.

• Journal of Korean Neurosurgical Society
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• v.60 no.1
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• pp.1-7
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• 2017

Objective : The diagnosis of shunt malfunction can be challenging since neuroimaging results are not always correlated with clinical outcomes. The purpose of this study was to evaluate the efficacy of a simple, minimally invasive cerebrospinal fluid (CSF) lumbar tapping test that predicts shunt under-drainage in hydrocephalus patients. Methods : We retrospectively reviewed the clinical and radiological features of 48 patients who underwent routine CSF lumbar tapping after ventriculoperitoneal shunt (VPS) operation using a programmable shunting device. We compared shunt valve opening pressure and CSF lumbar tapping pressure to check under-drainage. Results : The mean pressure difference between valve opening pressure and CSF lumbar tapping pressure of all patients were $2.21{\pm}24.57mmH_2O$. The frequency of CSF lumbar tapping was $2.06{\pm}1.26times$. Eighty five times lumbar tapping of 41 patients showed that their VPS function was normal which was consistent with clinical improvement and decreased ventricle size on computed tomography scan. The mean pressure difference in these patients was $-3.69{\pm}19.20mmH_2O$. The mean frequency of CSF lumbar tapping was $2.07{\pm}1.25times$. Fourteen cases of 10 patients revealed suspected VPS malfunction which were consistent with radiological results and clinical symptoms, defined as changes in ventricle size and no clinical improvement. The mean pressure difference was $38.07{\pm}23.58mmH_2O$. The mean frequency of CSF lumbar tapping was $1.44{\pm}1.01times$. Pressure difference greater than $35mmH_2O$ was shown in 2.35% of the normal VPS function group (2 of 85) whereas it was shown in 64.29% of the suspected VPS malfunction group (9 of 14). The difference was statistically significant (p=0.000001). Among 10 patients with under-drainage, 5 patients underwent shunt revision. The causes of the shunt malfunction included 3 cases of proximal occlusion and 2 cases of distal obstruction and valve malfunction. Conclusion : Under-drainage of CSF should be suspected if CSF lumbar tapping pressure is $35mmH_2O$ higher than the valve opening pressure and shunt malfunction evaluation or adjustment of the valve opening pressure should be made.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.2
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• pp.123-129
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• 2016

In this paper, results of produced PCU(Power Control Unit) prototype was showed by suggesting and maintaining optimal operation status which let the three functional modules automatically operate with its necessity by prioritizing operation process. In order to validate effectiveness of the suggested method, we produced a test PCU and examined the results. PCU consists of S3R(Sequential Switching Shunt Regulator), BCR(Battery Charge Regulator), and BDR(Battery Discharge Regulator): converting photovoltaic power into constant voltage at linked bus voltage; storing dump power in the battery which is an auxiliary energy storage device; and supplying power charged in battery to the load. To maintain its high reliability and optimal condition of these three power conversion modules, each module operates in parallel and stable bus voltage is required to be retained at all-time due to the nature of power supply for satellite.

• Journal of Chest Surgery
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• v.31 no.7
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• pp.650-659
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• 1998

Between August 1996 and August 1997, 22 patients underwent extracardiac Fontan operations. The basic diagnoses included univentricular heart of the right ventricular type (n=12); univentricular heart of the left ventricular type (n=4); tricuspid atresia (n=4); left isomerism, transposition of great arteries, ventricular septal defect and pulmonary stenosis (n=1); and criss-cross heart with uneven ventricle (n=1). The median age of the 14 men and 8 women was 29 months (range from 21 months to 26 years). Previous procedures included bidirectional cavopulmonary shunt (n=15, interval=15.6$\pm$3.4 months), Kawashima operation (n=4, interval=37.5$\pm$20 months), and classic Glenn shunt (n=1, interval=14 years). In 2 patients, extracardiac Fontan operations were done without any previous procedures. A 16- to 22-mm flexible Gore-Tex tube graft (n=18), Hemashield graft (n=3), or, alternatively, a nonvalved aortic allograft (n=1) was cut and anastomosed end-to-end between inferior vena cava and undersurface of pulmonary artery using Gore-Tex or Prolene suture in a running fashion. In risk Fontan patients (n=12), a communication between the extracardiac conduit and the right atrium was constructed. In the most 13 recent patients, the procedures were done without cross-clamping of the aorta and with a beating heart. Operative mortality was 9.1% (n=2). Complications included persistent chest tube drainage for more than 7 days (n=5), chorea (n=2), and low cardiac output (n=1). There were no late deaths. Follow-up echocardiogram (mean: 6 months) demonstrated satisfactory hemodynamic results in the surviving 20 patients. Potential advantages of this technique consist of minimization of surgical manipulation of atrial tissue, reduction or elimination of myocardial ischemia, creationof a uniform and stable inferior vena cava-to-pulmonary artery conduit, and increased flexibility and safety in certain high-risk patients such as those with increased pulmonary vascular resistance, pulmonary hypertension, and impaired ventricular function. Further investigations during a longer follow-up are needed to confirm the intermediate and long-term results, especially the reduction of late atrial arrhythmias.

• Journal of Chest Surgery
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• v.19 no.2
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• pp.280-287
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• 1986

Between March 1978 and August 1985, 29 cases at various congenital heart diseases were reoperated because of remnant shunt of residual anomalies at Seoul National University Hospital. They were consisted of 10 cases of Tetralogy, 4 simple VSD, 6 complicated VSD. 3 partial ECD, and 5 other rare congenital anomalies. The interval between the initial and the second procedure ranged from 1 day to 122 months [mean; 26.9 months]. In 4 cases of them, the second procedure was done during initial hospitalization within 3 weeks post-operatively. The primary operation intended to be corrective surgery except four whose primary operation was palliative or exploratory one even though it was done with extracorporeal circulation. The indication for second operation was mainly residual shunt or valvular obstruction due to patch detachment or inadequate relief of stenotic lesion. Others were paravalvular leak, valvuloplasty failure, prosthetic valve failure, and inadequate primary diagnosis. Four patients were dead [14.3%]; three complicated VSD`s and one Tetralogy. There were 7 cases of nonfatal complication with subsequent improvement except one [diffuse cerebral dysfunction].

• Journal of Chest Surgery
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• v.23 no.6
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• pp.1191-1203
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• 1990

Pulmonary atresia and ventricular septal defect with major aortopulmonary collateral arteries [abbreviated as PA+VSD+MAPCA in the following] has limited the success of attempts at accurate diagnosis and complete surgical repair. From April 1986 to September 1990, 23 patients with PA+VSD+MAPCA among 96 patients of PA+VSD in Seoul National University Children’s Hospital were encountered. The group comprised 14 male and 9 female patients with ages ranging from 17 days to 177 months [mean 49.6 months]. We operated one stage total repair on good pulmonary artery sized two patients by R.E.V. [Reparation a l’etage ventriculaire] and Rastelli operation respectively. And the 11 patients who had independent MAPCAs and hypoplastic central pulmonary artery were dealt with unifocalization and modified Blalock-Taussig Shunt and followed by second stage repair in 3 patients later. We successfully had managed 7 patients whose MAPCAs could be ligated with modified Blalock-Taussig Shunt and followed by second stage repair in 3 patients with R.E.V or Rastelli operation. Recently, three obstruction after 11 unifocalization procedures made us to try palliative right ventricle-pulmonary artery conduit operation by Gore-Tex vascular graft interposition under cardiopulmonary bypass. And so we managed another 3 patients with these procedures for the purpose of pulmonary artery growth whose central pulmonary artery were severely hypoplastic. We experienced one death after second stage repair whose central pulmonary artery was created by 12mm Gore-Tex vascular graft and was unifocalized.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.149-155
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• 2004

This paper presents how to find proper operating points of FACTS devices to enhance the steady-state security level considering line contigency analysis. Three generic types of FACTS devices such as series controllers, shunt controllers, and series-shunt controllers are introduced and applied to moximize a security margin and to minimize security indices. Security indices related to line flows and bus voltages are utilized and minimized iteratively in this paper. Contingency analysis is performed to detect the most severe single line fault. In various load conditions, FACTS devices are tested to establish appropriate preventive or corrective action without generation re-dispatching or load shedding. The FACTS operation scheme is verified on the IEEE 57-bus system in a line-faulted contingency.

• Journal of Chest Surgery
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• v.22 no.2
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• pp.348-356
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• 1989

Seventeen patients of pulmonary atresia with intact ventricular septum were underwent operation during 4.8years period from Jan. 1983 to Aug. 1988 at Seoul National university Hospital. The patients were composed of 8 males and 9 females, aging 1day to 2.5 years [mean 88 days]. We classified pulmonary atresia according to right ventricular morphology; those with tripartite ventricles in 12, those with no trabecular portion to the cavity in 0, and those with inlet portion only in 5. The tripartite approach to right ventricular morphology is helpful in selecting the type of initial palliative procedures. Palliative procedures were as follows; pulmonary valvotomy in 5 with 3 early survivors, mod B-T shunt in 4 with 3 early survivors, and palliative right ventricular outflow tract reconstruction in 4 with 1 early survivor. Effective preliminary palliation of pulmonary atresia are pulmonary valvotomy or palliative right ventricular outflow tract reconstruction in those with tripartite right ventricle, and modified Blalock-Taussig shunt in those with no infundibular portion. The approach to definitive repair is based primarily on the actual size of the tricuspid annulus and the right ventricular cavity. Definitive repair was as follows: definitive right ventricular outflow tract reconstruction in 4 with all survivors and mod. Fontan operation in 2 with one survivors. Right ventricular outflow tract reconstruction can be done as complete repair for patients who had adequate tricuspid annulus and right ventricular cavitary size and mod. Fontan operation for patients who severely hypoplastic tricuspid valve annulus or small right ventricular cavity.

• 전기의세계
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• v.14 no.3
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• pp.10-17
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• 1965

This paper presents a method of the voltage-reactive power control in the long and short range operations and introduces a conception, "optimum control pattern." The optimum control pattern, aiming at the over-all system control, is defined as the optimum voltage distribution which minimizes the system operating cost under the conditions that the specified power be supplied and the system voltage be kept within the specified bounds. The following procedure was adopted to obtain this optimum pattern. In the first place, a power system was divided into three blocks, namely, load, substation and generator. Lagrange's, multiplier method is applied to each block in turn, paying attention only at the operating voltage distribution. Phase angles at each bus are then modified so that the continuity of active power is maintained. This procedure may be called "block relaxation method with Lagrange's multipliers." In a long range operation, this control pattern determines the optimum installation capacity of reactive power sources. In a short range operation, it also gives the reference state of real time control and the optimum switching capacity of reactive power souces. The real time control problem is also studied from the standpoint of cooperation of control devices such as generators, shunt capacitors, shunt reactors and ratio load controllers. A proposal for the real time control will contribute to the automation of power system operation in the near future. in the near future.

• Journal of Chest Surgery
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• v.36 no.7
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• pp.523-526
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• 2003

A 44-year-old man had been admitted for dyspnea on exertion and abdominal distension. The echocardiography revealed abnormal mass in right atrium and tricuspid valve stenosis with right ventricular obliteration. The operation was performed with mass removal, enlargement of tricuspid valve opening, and right ventricular endocardiectormy. And then, atrial septal defect was made due to inadequate right ventricular volume. The patient's symptom was improved and he discharged without events. The endomyocardial fibrosis was diagnosed with microscopic examination. Eighteen months later, the patient was readmitted due to aggravated dyspnea and cyanosis. The right ventricular obliteration was progressed and pulmonary blood flow was severely decreased in follow up echocardiography. Palliative bidirectional cave-pulmonary shunt was performed due to functional single ventricle. The dyspnea and cyanosis was markedly improved. Bidirectional cavo-pulmonary shunt for advanced and isolated right ventricular endomyocardial fibrosis provided effective palliation at early postoperative period, However, long-term follow up is mandatory.