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As modern power systems become large and complicated, an automated voltage and reactive power control system is required in most developed countries due to the remarkable recent progress in computer networks and information technology. To date, voltage control has depended on human operators in the Korean power system. Accordingly, this paper proposes a universal intelligent voltage control system for bulk power systems based on sensitivity analysis and a main expert system. A detailed state space modeling technique is discussed, and an effective performance index is proposed to accelerate the searching performance of the expert system. As the searching strategy is an important factor for the speed of the expert system, the least-first search algorithm is applied using this performance index. The proposed system has been applied to the Korean power system, showing promising results.

Ultrasound (US) imaging is widely utilized as a diagnostic screening method, and deep learning has recently drawn attention for the analysis of US images for the pathological status of tissues. While low image quality and poor reproducibility are the common obstacles in US analysis, the small size of the dataset is a new limitation for deep learning due to lack of generalization. In this work, a convolutional neural network (CNN) using multiple feature maps, such as entropy and phase images, as well as a B-mode image, was proposed to classify breast US images. Although B-mode images contain both anatomical and textual information, traditional CNNs experience difficulties in abstracting features automatically, especially with small datasets. For the proposed CNN framework, two distinct feature maps were obtained from a B-mode image and utilized as new inputs for training the CNN. These feature maps can also be made from the evaluation data and applied to the CNN separately for the final classification decision. The experimental results with 780 breast US images in three categories of benign, malignant, and normal, showed that the proposed CNN framework using multiple feature maps exhibited better performances than the traditional CNN with B-mode only for most deep network models.

This paper propose an intelligent restoration aid system that assists the decision of power system operators for reliable and fast restoration processes when a blackout happened in massive power systems. This system consists of a topology processor and intelligent restoration aid system. The topology processor identifies the real-time embedded topology structure between power system facilities and determines the power outage section. The power system restoration aid system determines the feasible restoration path in terms of overloads and real power flow. Case studies demonstrate a promising possibility of practical application.

If the Low-frequency oscillations including Local and Inter-area Mode in power systems are not properly damped out, they can cause critical effects, including wide-area outage. In order to damp out these oscillations, the PSS (Power System Stabilizer) of each synchronous generator is typically used. This, however, cannot damp out inter-area oscillations. Although research on damping inter-area oscillations is conducted to resolve the mentioned problems, the Lead Lag Controller for damping the oscillations used in FACTS (Flexible AC Transmission System) devices including VSC (Voltage Source Converter) has limitations in that it is a linear controller designed at a linearized Power System models so there are some limitations incurred by the variable and unpredictable power system states, so that fixed controller parameters cannot properly damp out these oscillations. Meanwhile, the AI (Artificial Intelligence) techniques including supervised learning, unsupervised learning, and reinforcement learning are applied in various engineering fields to overcome a lot of nonlinear problems like those of power systems. In this paper, the ANN (Artificial Neural Network) controller, a kind of AI controller, was used to damp out inter-area oscillation at different power system operating conditions, after which the results were analyzed.

Recently, Many papers have been published on other's utility of the existing BESS (Battery Energy Storage System) equipment that stabilizing the output of the renewable energy and adjusting the frequency of the power system. In 2013, the EPRI has reported a study of the primary power plant starting using BESS for the replacement of two black start generators of American Electric Power (AEP) that will be torn down. As the social interest in the power outage has increased since wide-area blackout in South Korea in 2011 it is time to research not only a reliability of the power restoration plan but also reducing power restoration time. In case of wide area black-out, the primary transmission line should be energized at first after opening all circuit breaker in power system. Since these transmission lines are long-distance and no-load, various problems may befall in the process of energizing. In this paper, the restoration process using BESS for primary transmission line was analyzed. PSCAD / EMTDC was used for simulation.

If the Low-frequency oscillations in power systems are not properly damped out, they can cause critical effects, including wide-area outage. In 1996, Low-frequency oscillation incurred a wide-area outage and the economic, social loss from this phenomenon was estimated at 3 billion dollars. In order to damp out these oscillations, the PSS (Power System Stabilizer) is typically used. This, however, cannot damp out inter-area oscillations. Although research on damping inter-area oscillations is conducted to resolve the mentioned problems, the Lead Lag Controller for damping the oscillations used in FACTS (Flexible AC Transmission System) devices including VSC (Voltage Source Converter) has limitations in that it is a linear controller designed at a particular power system operating condition and there are some limitations incurred by the variable and unpredictable power system states, so that fixed controller parameters cannot properly damp out these oscillations. Meanwhile, the AI (Artificial Intelligence) techniques including supervised learning, unsupervised learning, and reinforcement learning are applied in various engineering fields in order to overcome a lot of nonlinear problems like those of power systems. In this paper, the ANN (Artificial Neural Network) controller, a kind of AI controller, was used to damp out inter-area oscillation at different power system operating conditions, after which the results were analyzed.

Power system restoration following a massive blackout starts with re-energizing Primary Restorative Transmission (PRT) systems at first. As power systems have been gradually enlarged and become more complex, periodical evaluation and reassignment of PRTs are needed. So far it has been decided by try and error approach by corresponding human experts to analyze and evaluate them. This paper presents an intelligent system that finds optimal primary restoration paths using analytic and heuristic knowledge from PSS/E data, and suggests an optimal PRTs depending on the condition of Ferranti effect or a reactive power capability margin of black-start generator. This system was tested in Korea Electric Power system, and showed a promising result.

This paper proposed an ANN (Artificial Neural Network) controller to damp out inter-area oscillation of a power system using BESS (Battery Energy Storage System). The conventional lead-lag controller-based PSSs (Power System Stabilizer) have been designed using linear models usually linearized at heavy load conditions. This paper proposes a non-linear ANN based BESS controller as the ANN can emulate nonlinear dynamics. To prove the performance of this nonlinear PSS, two linear PSS are introduced at first which are linearized at the heavy load and light load conditions, respectively. It is then verified that each controller can damp out inter-area oscillations at its own condition but not satisfactorily at the other condition. Finally, an ANN controller, that learned the dynamics of these two controllers, is proposed. Case studies are performed using PSCAD/EMTDC and MATLAB. As a result, the proposed ANN PSS shows a promising robust nonlinear performance.

Background There are few articles on mortality and morbidity of adult patients with Eisenmenger's syndrome (ES) in the current era when disease targeting therapy (DTT) has been available. Methods and results 198 patients (a median age 35years, 64% female) with ES who visited the 16 participating institutes in Japan and Korea from 1998 to 2009 were enrolled. Clinical data during adulthood were collected from each institutional chart and analyzed centrally. During a median follow-up of 8years, 30 patients died including 14 sudden deaths. 89 patients took oral medication of DTT and clinical improvement was observed in 54 of them. However, survival rate in patients taking DTT was not different from those without (87% vs 84%, p=0.55). When the clinical data in between first and last clinic visits were compared in 85 patients, the patients with NYHA ≧ III increased from 24% to 48% (p 2 decreased from 89% to 85% (p=0.008) and hematocrit increased from 51.4% to 52.9% (p=0.04). Non-survivors had poorer NYHA function class, lower body weight (BW), lower body mass index (BMI), and higher serum level of Cr at the first visits than survivors. Conclusions Long term survival and clinical status of adult patients with ES remains unsatisfactory even in the current era of DTT. Poor NYHA functional class, low BW, low BMI and high serum level of Cr were related to mortality. DTT therapy improved clinical status in many patients with Eisenmenger's syndrome, but no significant impact on survival could be shown.

During the restoration process of primary restorative transmission system, some over voltages may happen due to nonlinear interaction between unloaded transformers and transmission systems. These over voltages caused by harmonic resonance can be suppressed by inserting damping loads before energizing transformers. But it is very difficult to predict the occurrence possibility of harmonic resonance and complex simulation must be repeated to estimate the sufficient damping loads. This paper presents a damping loads prediction system to prevent harmonic resonance. Detailed analysis of the relationship between harmonic resonance and the amount of damping loads is discussed. The prediction system is developed using a curve fitting and a neural network based on this relationship. A curve fitting used a Gaussian function based on non-linear least square method and multi-layer back-propagation neural network is applied. The system is applied to primary restorative transmission lines in korean power system and the result showed satisfactory performance.

This paper introduces the application of state estimation to double bus double breaker distribution substations, which are typically used in the Korean power system, to improve the reliability of substation automation systems. In spite of the recent remarkable progress in the field of sensors and equipments, it is hard to detect device malfunctions or degraded devices automatically in the supervisory monitoring system. The object of the proposed system is not the state estimation itself, but its application to the supervisory detection of the malfunction or degradation of the devices. The supervisory monitoring process consists of a two step procedure-topology processing and normal state estimation. In a substation, the on-off states of the circuit breakers determine the topology. This paper mainly presents the topology processing expert system including the knowledge representation. The expert system is operated with a predefined period to identify and correct topological errors in the distribution substations. The proposed system is now in the field test stage in the Sanchung pilot substation and it will be applied to the next generation substation automation system in Korea.

Preexcitation by accessory pathways (APs) is known to cause dyssynchrony of the ventricle, related to ventricular dysfunction. Correction of ventricular dyssynchrony can improve heart failure in cases of dilated cardiomyopathy (DCMP) with preexcitation. Here, we report the first case of a child with DCMP and Wolff-Parkinson-White (WPW) syndrome treated with amiodarone and radiofrequency catheter ablation (RFCA) in Korea. A 7-year-old boy, who suffered from DCMP and WPW syndrome, showed improved left ventricular function and clinical functional class after treatment with amiodarone to eliminate preexcitation. QRS duration and left ventricular ejection fraction (LVEF) were inversely correlated with amiodarone dosage. After confirming the reduction of preexcitation effects in DCMP, successful RFCA of the right anterior AP resulted in LVEF improvement, along with the disappearance of preexcitation. Our findings suggest that ventricular dyssynchrony, caused by preexcitation in DCMP with WPW syndrome, can worsen ventricular function and amiodarone, as well as RFCA, which should be considered as a treatment option, even in young children.

As modern power systems become large and complicated, the automated voltage and reactive power control system is required in most developed countries due to the recent amazing progress of computer net works and information thechnology. So far the voltage control has been depend on human operator in korean power system. This paper presents an intelligent voltage control system based on sensitivity analysis and artificial intelligence technology. Detailed state space modeling technique is discussed and a new performance index is proposed to speed up the searching performance of the expert system. As the searching strategy is very important factor of the speed of expert system the least first search algorithm is applied using this performance index. The intelligent voltage control system is applied to the Jeju power system. As a result, case studies showed a promissing application of the intelligent voltage control system.

Fragmented QRS (fQRS) on 12-lead electrocardiography reflects conduction delay caused by myocardial fibrosis and dysfunction. Ventricular fibrosis detected by late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) is reportedly correlated with worse clinical outcomes in adults with repaired tetralogy of Fallot (TOF). The aim of this study was to assess whether the presence of fQRS is associated with right ventricular (RV) fibrosis or dysfunction in this patient group. In 37 consecutive patients (median age 30 years, median age at repair 6.6 years), the number of leads showing fQRS, defined as the presence of >2 notches on the R/S wave in ≥2 contiguous leads, was counted. RV systolic function, dilatation, and LGE score were measured using LGE CMR. Ventricular LGE was observed mainly at the previous surgical sites: the RV outflow tract (33 of 37), ventricular septal defect patch region (15 of 37), and RV anterior wall (11 of 37). Fragmented QRS was found mostly in the right and mid precordial leads. The fQRS group (n = 20) demonstrated higher RV LGE scores (p

Loeys-Dietz syndrome (LDS) is an inherited disorder that is characterized by the triad of arterial tortuosity and aneurysms, hypertelorism and a bifid uvula or cleft palate. The disease is caused by heterozygous mutations in the genes encoding transforming growth factor β receptors 1 and 2 (TGFBR1 and TGFBR2, respectively). However, studies of patients with LDS are limited in Korea. From June 2000 to December 2010, 13 patients (10 probands) diagnosed with LDS were enrolled. The multidisciplinary data of the patients were reviewed retrospectively. The frequency of each clinical manifestation in Korean patients with LDS was compared with Western populations as described in the report by Loeys et al. Twelve (92%) of the 13 LDS patients had arterial tortuosity, 9 (69%) patients had hypertelorism and 11 (85%) patients had bifid uvula or cleft palate. Mutations in either TGFBR1 or TGFBR2 were detected in nine probands (90%). Of the mutations, five novel mutations were detected; three in TGFBR2 and two in TGFBR1. Blue sclera and atrial septal defect were not observed in the Korean patients, and the frequency of blue sclera was significantly lower in our Korean population than previously-described Western population (0 vs 40%; P=0.005). Despite the restricted number of patients in our study, we identified five novel mutations in the TGFBR1 and TGFBR2 genes and, except for blue sclera, no differences in phenotype are apparent between Korean patients and Western patients.

Hunter syndrome (mucopolysaccharidosis II, MPS II) is a rare, X-linked disorder of glycosaminoglycan (GAG) catabolism caused by a deficiency in the activity of the lysosomal enzyme, iduronate-2-sulfatase (I2S). In this study, the medical records of 75 Korean patients with Hunter syndrome (74 males, 1 female) were retrospectively reviewed to investigate the frequency of organ involvement and survival at a single center. The three most common symptoms of organ involvement were hepatosplenomegaly (99%), facial dysmorphism (97%), and frequent otitis media (91%). Cardiovascular involvement was also common including valvular abnormalities (89%), left ventricular hypertrophy (68%), and hypertension (30%). The 19 patients who died had a median age of 16.8 years at the time of death. Four of them died within 1 year of the start of enzyme replacement therapy; autopsy showed myocardial infarction with severe coronary artery disease in one patient. Two other patients died due to pneumonia and sleep apnea. In one case, the cause of death was not investigated. The high incidence of hypertension, and the presence of valvular heart disease indicates that close cardiac monitoring is mandatory in all patients with Hunter syndrome, especially relatively older patients even if they are being treated with enzyme replacement therapy. © 2011 Wiley Periodicals, Inc.

The existing power flow has a single direction to the line end but the bidirectional power flow will possibly occur depending on the output capacity in the 22.9[kV] distribution power system connected with the dispersed generation(DG). So these characteristics would influence the power system management. The DG have many advantages such as assistance source, Load share etc. So the utility must apply the bidirectional protection system so as to maximize an advantage of DG. This paper describes the field test case of bidirectional protective device in order to investigate the device performance when applied to bidirectional power system. We have tested in the power system test site of KEPCO and these tests provide the basis for performance verification test of bidirectional protective device in the power system.

Background: The optimal surgical strategy for coarctation of the aorta (CoA) with ventricular septal defect (VSD) is controversial. The aim of this study is to evaluate the clinical outcome of a single-stage repair of CoA with VSD. Methods: We reviewed 72 patients who underwent single-stage repair for CoA with VSD between January 1995 and December 2007. There were 43 males and 29 females. The median age of the patients was 28 days (range = 3 to 188) and median weight was 3.7 kg (range = 2.16 to 5.6). Deep hypothermic circulatory arrest was used in 22 patients and selective antegrade cerebral perfusion was performed in 43 patients. Results: There were no operative deaths and one late death at a median follow-up of 60 months (range = 16 to 158). Postoperative complications were left main bronchus compression requiring aortopexy in one patient and recoarctation requiring balloon dilatation in one patient. Subaortic stenosis occurred in two patients and surgical repair was performed. Conclusions: One-stage simultaneous repair can be performed with a low risk at an early age. (J Card Surg 2011;26:420-424)

The reactive power, unlike frequency, has local characteristics and it has relied on the manual operation in a local reactive power control station so far. Since coordination or integrated control was possible due to the recent advances in computers and communication networks, the hierarchical voltage control system, consisting of primary, secondary, and tertiary, has been already applied to the real-life situations of several developed countries in Europe. Recently, the Korea power system has been operated more closely to stability limits because of rapid growth in load-demand as seen in Europe. For this reasons, KEPCO recognized the need of the voltage control system and developed the voltage control system. In this paper, we developed intelligent voltage control system for domestic system using numerical algorithm based on the sensitivity matrix and expert system, and dynamic response characteristics of the developed system investigated as a preliminary step for interfacing RTDS(Real Time Digital Simulator). In addition, the developed system performance was verified.

As usual, the microgrid operates in grid-connect mode, but, when a fault occurs in the upstream grid, it should disconnect and shift into islanded operation mode. In grid-connect mode, the controlling power at the PCC is necessary management function rather than the frequency and voltage. However, the controlling the frequency and voltage is asked in islanded mode. To achieve these management goals appropriately, the cooperative control strategy among microsources is needed. This supervisory control action is executed at MMS. In this paper, the cooperative control strategy of microgrid components is presented and the management performance is evaluated by using microgrid pilot plant. The pilot plant consists of the PV, PV/Wind Hybrid system, BESS, diesel generators, and RLC loads, which are connected to 380V low voltage lines. The test results show that the proper control strategy can ensure stability of microgrid in islanded mode and maintain the power at the PCC at desired value successfully.

This paper describes a new methodology for grid expansion planning considering the probabilistic reliability of a composite power system including wind turbine generators (WTG). The proposed model includes capacity limitations and transmission line unavailability. The importance of renewable energy sources has been growing at a rapid rate due to environmental concerns. In particular, wind energy is one of the most successfully utilized such source in producing electrical energy. The random nature of wind speed can be incorporated in the evaluation by representing the WTG as a multi-state model. This type of model comes from a nodal equivalent load duration curve based on a nodal effective load model developed in recent years. In this paper, a heuristic method is used to search for the best reliability level among various scenarios with candidate lines.

In this paper, we study the Stackelberg game-based evolutionary game with two players, generators and energy users (EUs), for monetary profit maximization in real-time price (RTP) demand response (DR) systems. We propose two energy strategies, generator’s best-pricing and power-generation strategy and demand’s best electricity-usage strategy, which maximize the profit of generators and EUs, respectively, rather than maximizing the conventional unified profit of the generator and EUs. As a win–win strategy to reach the social-welfare maximization, the generators acquire the optimal power consumption calculated by the EUs, and the EUs obtain the optimal electricity price calculated by the generators to update their own energy parameters to achieve profit maximization over time, whenever the generators and the EUs execute their energy strategy in the proposed Stackelberg game structure. In the problem formulation, we newly formulate a generator profit function containing the additional parameter of the electricity usage of EUs to reflect the influence by the parameter. The simulation results show that the proposed energy strategies can effectively improve the profit of the generators to 45% compared to the beseline scheme, and reduce the electricity charge of the EUs by 15.6% on average. Furthermore, we confirmed the proposed algorithm can contribute to stabilization of power generation and peak-to-average ratio (PAR) reduction, which is one of the goals of DR.

The aim of this study was to investigate clinical manifestation and causes of chest pain in adults with congenital heart disease. Of 966 patients in our Adult Congenital Heart Clinic, 50 patients had cyanosis (cyanosis [+]), and 916 patients did not have cyanosis (cyanosis [−]). Fifty-four patients (16 male and 38 female) with a history of chest pain requiring medical care were selected: 33 were in the cyanosis (+) group, and 21 were in the cyanosis (−) group. Medical records were reviewed. The causes of chest pain were (no. cyanosis [+], no. cyanosis [−], respectively) as follows: idiopathic (n = 19, n = 10), pulmonary hemorrhage (n = 6, n = 0), pulmonary tuberculosis (n = 2, n = 0), pulmonary thromboembolism (n = 4, n = 0), localized musculoskeletal (n = 1, n = 1), myocardial ischemia (n = 1, n = 1), and arrhythmia (n = 2, n = 9). Patients with cyanosis had much higher frequency of chest pain compared with patients without cyanosis (33 of 50 vs. 21 of 916, p < 0.0001). Chest pain in adults with congenital heart disease has diverse causes. Meticulous evaluation of chest pain in adults with congenital heart disease is required to differentiate correctable causes from idiopathic or incurable ones.

Intracardiac thrombosis in patients with a dilated cardiomyopathy can be life threatening. This study investigated the incidence, risk factors, and outcome of intracardiac thrombosis in children with dilated cardiomyopathy. A retrospective review of the clinical records was performed in 83 children with dilated cardiomyopathy diagnosed from January 1995 to December 2008. Intracardiac thrombi were detected in 5 patients (6.0%). The intracardiac thrombi were found mainly in the left ventricle (n = 3). One patient had a thrombus in the left atrium at the time of diagnosis, and a right ventricular thrombus was found in 1 patient with unrepaired ventricular septal defect complicated by pulmonary hypertension. Intracardiac thrombosis developed during rapid deterioration of ventricular function, and all patients had a poor ejection fraction of the left ventricle. All patients were treated with heparinization, and thrombectomy was performed in 1 patient. Three patients achieved complete resolution of the thrombus without further embolic complications. Careful evaluation and aggressive anticoagulation are necessary for the prevention of intracardiac thrombosis in children with poor ventricular function, especially during rapid deterioration of ventricular function.

The objective of this study was to report the outcome of fenestration closure using either an Amplatzer Vascular Plug I or detachable coils in patients undergoing extracardiac Fontan procedure with conduit fenestration. We reviewed the medical records of 23 patients who underwent transcatheter closure of conduit fenestration with the extracardiac Fontan procedure. The median age at fenestration closure was 57 months (range 36 to 98). The median interval between the operation and the procedure was 28 months (range 8 to 68). The Amplatzer Vascular Plug I (AVP) was used in 16 patients, and detachable coils were used in 7 patients. In the coil group, we used 1 coil in 3 patients, 2 coils in patients, and 3 coils in 1 patient, all based on angiographic results. In the AVP group, we used a device that was at least 1 mm larger than the initial fenestration size. No immediate or long-term complications were associated with the procedure or with the closure devices. On final follow-up, 3 of 7 patients (43%) in the coil group had complete closure, and 17 of 17 patients (100%) in the AVP group had complete closure. The AVP showed good results for transcatheter closure of a conduit-type fenestration and was found to perform better than the detachable coil.

We propose a new decaying dc component estimation algorithm for digital relaying. Fault currents tend to include a dc decaying component. This component decreases the accuracy and speed of the protection relay operation. The proposed algorithm can estimate and eliminate the dc decaying component from fault current signals after one cycle from the fault instant. Also, it can be applied to a conventional discrete Fourier transform to calculate phasor quantities of fault currents in a digital protection relay. In the proposed algorithm, the dc decaying magnitude and time constant are estimated exactly by integrating fault currents during one cycle. The dc decaying component is eliminated by subtracting the dc value at each sampling instant. To verify the performance of the proposed algorithm, we performed a dc component estimation test and distance protection test using PSCAD/EMTDC. The results of the PSCAD/EMTDC simulation showed that the proposed algorithm can estimate dc components exactly from fault currents and can be applied to digital protection relays for phasor extraction.

Microsatellite markers are an essential tool for genetic linkage analysis because of their high polymorphism content. Four hundred commercially available markers covering the entire genome were genotyped from 578 sib individuals from 249 Korean families. Allelic frequencies and heterozygosities were determined for each marker loci and compared between Korean, Taiwanese, Japanese and Caucasian populations. In the three Asian populations, 10-13% of the markers had less than 0.6 heterozygosity, whereas in the Caucasian population, only 0.5% of the markers had less than 0.6 heterozygosity. Mean identical by descent (IBD) values were calculated for 578 sib individuals. Analysis of IBD values greater than 0.5 suggested that markers with low heterozygosity can also provide positive linkages, at least for the IBD sharing method of model-free linkage analysis. The data presented in this study will be a useful reference for genome-wide screens of Koreans and comparative studies with other ethnic populations.

ObjectivesTo maintain pulmonary valvar function subsequent to repair of tetralogy of Fallot, we have inserted a homograft monocusp when a transjunctional patch was required. In this study, we have evaluated the mid- to long-term outcomes, aiming to determine the durability of the homograft.MethodsAmong 218 repairs performed for tetralogy of Fallot between July, 1996, and June, 2005, we inserted homograft monocusps in 54 patients, 4 of whom had associated absent pulmonary valve syndrome, 3 had pulmonary valvar atresia, and 1 had an atrioventricular septal defect with common atrioventricular junction. The median body weight at surgery was 7.8 kilograms, with a range from 3.9 to 42 kilograms. The function of the monocusp valve was assessed by regular echocardiography, using the Kaplan-Meier method and the Cox regression model for statistical analyses.ResultsThere were 2 early deaths (3.7%), associated with respiratory infection. No late deaths were observed during the follow-up, which ranged from 0.3 to 120 months, with a median of 64.3 months. Freedom from valvar dysfunction was 67.2 ± 6.7% at 1 year, 37.1 ± 7.3% at 3 years, 23.8 ± 6.7% at 5 years, and 21.2 ± 6.4% at 7 years. We needed to replace the valve in 1 patient during follow-up. We found that ABO blood group incompatibility, stenosis of the pulmonary arteries, and associated absent pulmonary valve syndrome all adversely affected the function of the monocusp.ConclusionOur experiences show that insertion of a homograft monocusp can prevent pulmonary regurgitation in the early period after repair of tetralogy of Fallot, but the effects are limited in duration as degeneration progressed. We still need to determine whether this finding can improve the longer-term function of the right ventricle.

Noonan syndrome (NS) is a congenital abnormality that affects multiple parts of the body. Approximately 50% of cases are caused by mutations in the PTPN11 gene. NS shares many clinical features with a group of developmental disorders including Costello syndrome and cardio-facio-cutaneous (CFC) syndrome. Recently, KRAS and SOS1 were identified as causative genes for NS. Moreover, mutations in several genes associated with the Ras-mitogen-activated protein kinase (MAPK) pathway, including HRAS, BRAF, MEK1, and MEK2 were identified in patients with Costello syndrome and CFC syndrome. Accordingly, this study carried out mutation analysis of nine genes including PTPN11, SOS1, GRB2, KRAS, HRAS, NRAS, BRAF, MEK1, and MEK2 associated with the Ras-MAPK pathway in 14 Korean patients with NS. Seven patients were found to have mutations in the PTPN11 gene. Mutation analyses of the other genes did not reveal any disease causing mutations except for one unclassified variation in the 3'-untranslated region of the HRAS gene (c.*1C>T). The patient's father also had the same substitution with the normal phenotype. Therefore, this variation is believed to be either a rare polymorphism or a disease-related variation with variable penetrance. The Ras-MAPK pathway has now emerged as a key cascade in a group of similar developmental disorders as well as in many types of cancers. This study found that, with the exception of PTPN11, mutations in genes related to the Ras-MAPK pathway appear to be uncommon, at least in Korean patients with NS.

Eisenmenger syndrome (ES) is commonly associated with depressive symptoms and elevated N-terminal pro-B-type natriuretic peptide (NT-proBNP). We investigated the predictive value of depressive symptoms and NTproBNP levels for long-term outcomes in patients with ES.Blood was drawn to measure NT-proBNP, and depressive symptoms were measured using the Korean version of the Beck Depression Inventory (BDI) in an outpatient clinic sample of 64 patients with ES (67% female; median age = 41.5 years [range, 21.0-74.8 years]). Cardiac events (hospitalization, emergency department visits, and cardiac death) were monitored during 3 years of follow-up.During the follow-up period, 15 (23.4%) patients experienced a cardiac event. The combination of depressive symptoms and NT-proBNP levels better predicted future cardiac events than either variable alone. Patients with NT-proBNP510 pg/ml and a total BDI score10 had a 9.6 times higher risk for cardiac events than did patients with NT-proBNP ≤ 510 pg/ml or total BDI score ≤ 10 (p.001).Depressive symptoms and NT-proBNP levels are both associated with adverse clinical outcomes in ES.

Cases of iatrogenic coronary artery fistulas draining into the left ventricle after surgical myectomy for hypertrophic obstructive cardiomyopathy have been published as sporadic reports. However, its management scheme and prognosis are not clear because of the low incidence. A 46-yr-old woman was hospitalized for evaluation of chest pain and shortness of breath for 3 months. Transthoracic echocardiographic examination showed typical hypertrophic obstructive cardiomyopathy with a peak pressure gradient of 71 mmHg across the left ventricular outflow tract. The patient underwent surgical septal myectomy. Postoperative color Doppler imaging revealed a diastolic blood flow from the interventricular septal myocardium to the left ventricular cavity, i.e. iatrogenic coronary artery fistula to the left ventricle. Ten days later, the fistula closed spontaneously which was diagnosed by transthoracic echocardiography and confirmed by coronary angiography.

Background: The aim of this study was to investigate the incidence rate and epidemiologic patterns of Kawasaki disease in Korea for a 3 year period during 2000 to 2002. Methods: An epidemiologic survey on Kawasaki disease was retrospectively performed. The questionnaire was sent to all 112 hospitals having pediatric residency programs, and obtained data were analyzed. Results: The 9150 cases of Kawasaki disease from 92 hospitals which responded (response rate, 82.1%) included 5515 males and 3635 females (male : female ratio, 1.52:1). The incidence rate per 100 000 children

Service restoration following a complete or partial collapse starts with reenergizing a transmission line from black-start generators. Ferranti effect and line charging problems can arise as unloaded transmission line is reenergized. This paper presents analytical results on the primary restorative transmission system focused on the problems during the early restoration process. Methodologies are presented that handle load pick-up to compensate Ferranti effect, and terminal voltage and reactive capability limitation of black-start generators about self-excitation. An algorithm for static analysis about these methodologies is developed, and EMTDC simulation for verifying the efficiency of the algorithm is performed.

When faults occur in a distribution network, blackout loads must be restored as fast as possible to minimize interruption of electric service. This paper presents an expert system to restore distribution networks. The system is designed to minimize switching operations in a heuristic sense by using heuristic rules. The restoration process is converted to the feasible path finding problem in the state space of expert system by application of general topological knowledge base. Multiple load transfer algorithm is proposed to deal with complex situations.

Leakage impulse current of the faulty insulators was experimentally studied. The leakage impulse current was characterized in terms of the phase-time base of the applied voltage. The study showed that the leakage impulse is observed only in a distinct location in phase-time space. Based on the findings, prioritized maintenance scheduling was proposed, which could be used for status monitoring of insulators and distribution feeders.

Purpose: The purpose of this paper is to analyze the feasibility of the full sternotomy with minimal skin incision and its related complications and risks. Methods: A total of 405 patients with simple congenital heart disease underwent open heart surgery exclusively under full sternotomy with minimal skin incision. We reviewed the available medical records of the patients retrospectively. Bypass time, aorta cross clamp time, and period of hospital stay were compared with the control group (223 patients with standard long skin incision). Results: Full sternotomy with minimal skin incision provided adequate surgical views and successful repair was done in all patients. There was no mortality. One patient had chylopericardium after the operation and another patient had a postoperative bleeding at the sternum. Minimal skin incision took the similar aorta cross-clamp time and total cardiopulmonary bypass time compared with full skin incision in atrial septal defect patients. Among the ventricular septal defect patients, minimal skin incision took a little longer aorta cross-clamp time (10%). but similar total cardiopulmonary bypass time compared with full skin incision. Conclusion: Minimal skin incision with full sternotomy provides improved cosmetic results. There was no increased mortality and morbidity using minimal access. It can be applied to more complex congenital heart disease contrast to other minimal invasive techniques for atrial septal defect.

The diagnosis of common arterial trunk (truncus arteriosus communis) is suspected when the chest radiogram shows a combination of cardiomegaly with oval configuration, increased pulmonary vascularity, narrow superior mediastinum, concave pulmonary arterial segment and right aortic arch in a patient with cyanosis and cardiac murmur. In most cases, echocardiography can provide complete morphological information of common arterial trunk and its associated lesions, although magnetic resonance imaging can provide more objective images with clearer visualization of the adjacent mediastinal structures including thymus. Cardiac catheterization for calculation of pulmonary vascular resistance should be performed for patients older than 3 months. When catheterization is performed, angiograms are obtained for a better understanding of the pathology. The ventricular septal defect and overriding common arterial trunk are best shown in long axis view. The dominant vessel arising from the common arterial trunk is the aorta in the majority of cases. When the ascending aorta is smaller than the pulmonary artery, associated interruption of the aortic arch should be suspected. The origin of the pulmonary artery from the common arterial trunk can be seen in right and left anterior oblique views. Preferred echocardiographic views for evaluation of the pulmonary arterial anatomy are high-parasternal and suprasternal views. Truncus arteriosus can be diagnosed in the fetus by using high-resolution sonography. For fetal screening of common arterial trunk, a three-vessel view is very helpful. It is an orthogonal transverse view of the fetal upper mediastinum where the main pulmonary artery, ascending aorta and superior vena cava are arranged in a line. When there are only two vessels in the three-vessel view, common arterial trunk is suspected. Once the diagnosis of common arterial trunk is made in the fetus, fluorescent in situ hybridization (FISH) should be performed to exclude del 22(q11) or CATCH 22 syndrome.

Purpose Myocardial infarction in children with total occlusion of a coronary artery after Kawasaki disease is rare due to multiple collateral vessels. We aimed to investigate the changes in coronary perfusion associated with coronary artery occlusion after Kawasaki disease. Materials and methods Eleven patients with coronary artery occlusion after Kawasaki disease were investigated. Serial coronary angiographies after total occlusion of a coronary artery were reviewed and the changes were described in all patients with additive information collected. Results The median age at the occlusion was 5.9 years old. The interval to occlusion was 6.2±6.9 years. Four left anterior descending coronary artery total occlusions and 10 right coronary artery total occlusions were detected. Immediate coronary artery bypass graft for left anterior descending coronary artery total occlusion made right coronary total occlusion occurred in all except one patient and the intervals thereof were 1 year, 1.8 years, and 4 years. Collaterals to the left coronary artery regressed after recanalization, while new collaterals to the right coronary artery developed. In three, collaterals to the right coronary artery decreased without recanalization without clinical signs. Conclusion The right coronary artery should be followed up carefully because of possible occlusion of new onset or changes in collaterals.

An integrated fuzzy expert system is presented to diagnose various faults that may occur in a regional transmission network and substations. Fuzzy reasoning method is applied, and it is discussed in detail. Discrimination of false operations or nonoperations of protective devices as well as the fault identification scheme are also analyzed, together with the fuzzy inference process. The proposed system is designed to improve efficiency, generality, and reliability of the solution. The system will replace a fault diagnosis system that had been tested as a part of an intelligent support system on a local control center in Korea.

A segmented polyurethane (SPU) film was chloromethylated and subsequently dithiocarbamated. The treated films were immersed in solutions containing poly(ethylene glycol) methacrylate (PEGMA) or N,N-dimethyl-acryl amide (DMAAm) and irradiated with ultraviolet (UV) light. The resultant surfaces were highly wettable with water. The surface chemical compositions, as determined by X-ray photoelectron spectroscopy, indicated that surface graft polymerization, initiated from surface-derivatized dithiocarbamate, had occurred and had altered the surface properties and the composition of SPU. The platelet adhesion test using platelet-rich plasma showed minimal adhesion for the poly(PEGMA)-grafted surface, followed by the poly(DMAAm)-grafted surface. © 1999 John Wiley & Sons, Inc. J Biomed Mater Res, 47, 564–567, 1999.

We present a new method for highly spatio-resolved graft-copolymerized surface fabrication, in which the stem design (parent graft chain length) and the branch design (daughter graft chain length a...

The aim of this study was to investigate the incidence rate and epidemiologic patterns of Kawasaki disease in Korea for the 3-year-period, 2003-2005.The questionnaire for an epidemiologic survey on Kawasaki disease was distributed to all 102 Korean hospitals that conduct pediatric residency programs, and obtained data were analyzed upon receipt.The 9662 patients of Kawasaki disease from 85 hospitals that responded (response rate, 83.3%) consisted of 5877 males and 3785 females (male:female ratio, 1.55:1). The incidence rate per 100,000 children5-year-old was 104.2 in 2003, 106.4 in 2004, and 104.6 in 2005 (average rate, 105.0). Their mean age of onset was 33.3 months, and the proportions of sibling cases and recurrent cases were 0.29% and 2.0%, respectively. Coronary arterial abnormalities were detected at follow-up by echocardiogram in 18.8% of all such cases including dilatations of 18.0% and aneurysms of 2.5%.The average annual rate of incidence, 105.0/100,000 in children5-year-old is the second highest reported rate in the world.