• Journal of Chest Surgery
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• v.36 no.6
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• pp.384-390
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• 2003

Background: Since Ross and Sormeville first reported the use of aortic homograft valve for correction of pulmonary atresia in 1966, homograft valves are widely used in the repair of congenital anomalies as conduits between the pulmonary ventricle and pulmonary arteries. On the basis of these results, we have used it actively. In this report, we describe our experience with the use of cryopreserved valved homograft conduits for infants and children requiring right ventricle to pulmonary artery connection in various congenital cardiac anomalies. Material and Method: Between January, 1996 and December 2001, 27 infants or children with a median age of 16 months(range 9days to 18years) underwent repair of RVOTO using homograft valved conduit by two surgeons. We studied 22 patients who have been followed up at least more than one year. The diagnosis at operation included pulmonary atresia with ventricular septal defect (n=13), truncus arteriosus (n=3), TGA or corrected TGA with RVOTO (n=6). Homograft valved conduits varied in size from 15 to 26 mm (mean, 183.82 mm). The follow-up period ranged from 12 to 80.4 months (median, 48.4 months). Result: There was no re-operation due to graft failure itself. However, early progressive pulmonary homograft valve insufficiency developed in one patient, that was caused by dilatation secondary to the presence of residual distal pulmonary artery stenosis and hypoplasia after repair of pulmonary atresia with ventricular septal defect. This patient was required reoperation (conduit replacement). During follow-up period, there were significant pulmonary stenosis in one, and pulmonary regurgitation more than moderate degree in 3. And there were mild calcifications at distal anastomotic site in 2 patients. All the calcified homografts were aortic in origin. Conclusion: We observed that cryopreserved homograft conduits used in infant and children functioned satisfactorily in the pulmonic position at mid-term follow-up. To enhance the homograft function, ongoing investigation is required to re-establish the optimal strategy for the harvest, preservation and the use of it.

• Journal of Korean Society of Transportation
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• v.19 no.1
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• pp.101-114
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• 2001

Transportation enterprises should maintain constant and qualitative operation. Thus, in short period, transportation enterprises don't change supply in accordance with demand. In the result, transportation enterprises don't reduce operation in spite of management deficit at will. In freight transportation type, less-than-truckload(LTL) has more relation with above transportation feature than truckload(TL) does. Because freight transportation supply of TL is more flexible than that of LTL in correspondence of freight transportation demand. Relating to above mention, it appears that shortage of road and freight terminal of LTL is larger than that of TL. Especially in road and freight terminal comparison, shortage of freight terminal is larger than that of road. Shortage of road is the largest in 1990, and improved after-ward. But shortage of freight terminal is serious lately. So freight terminal needs more expansion than road, and shows better investment condition than road. Freight terminal expansion brings road expansion in LTL, on the contrary, freight terminal expansion substitutes freight terminal for road in TL. In transportation revenue, freight terminal's contribution to LTL is larger than that to TL. However, when we adjust quasi-fixed factor - road and freight terminal - to optimal level in the long run, in TL, diseconomies of scale becomes large, but in LTL, economies of scale becomes large. Consequently, it is necessary for TL to make counterplans to activate management of small size enterprises and owner drivers. And LTL should make use of economies of scale by solving the problem, such as nonprofit route, excess of rental freight handling of office, insufficiency of freight terminal, shortage of driver, and unpreparedness of freight insurance.

• Archives of Reconstructive Microsurgery
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• v.5 no.1
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• pp.137-146
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• 1996

There has been no general agreement about optimal time for nerve surgery in the closed brachial plexus injury(BPI). From our early experiences, we knew by chance that spontaneous recovery in BPI patients may begin even later than 8 months after injury. Authors' strategy, which was based on our early experiences, for the treatment of closed fresh injury was 'wait and see' unlit 8 months after injury. From 1985 to 1994, we observed 103 patients with BPI. All of them did not have any operation until 8 months after injury. There were 95 men and 8 women with a mean age of 29 years. Motorcycle injury(31%) and vehicle accident(28%) were main causes of injury. Whole plexus types were observed in 56 patients(54%), upper plexus types in 29(28%), lower plexus types in 3(3%), and infraclavicular types in 15(15%). Electromyography was performed in all patients. This was repeated every three months to detect the recovery. Results were evaluated by authors' criteria, in which AMA system of brachial plexus impairment was modified. Duration of follow up was average 25 months. 47 patients(46%) showed spontaneous improvement, which was initially detected at average 7.8 months(range,3 months-16 months) after trauma by electromyography. The average score of these 47 patients improved from 14.8 points to 39.8 points.31 patients(30%) had nerve surgery such as nerve graft, neurotization or neurolysis. Average duration from injury to nerve surgery, was 10 months. Among 31 patients who had nerve surgery, 16 patients improved from preoperative 21.5 points to postoperative 36.3 points in average. Because spontaneous recovery began in average 7.8 months after injury, we think that it would be better to 'wait and see' for at least one year in patients with closed BPI expecting spontaneous recovery.

• Journal of Chest Surgery
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• v.42 no.4
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• pp.464-472
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• 2009

Background: We analyzed the clinical results and the factors for survival of patients who underwent extracorporeal life support system after adult cardiovascular surgery. Material and Method: We retrospectively reviewed the medical record of 44 patients (1.6% of the total adult cardiovascular surgical cases) who underwent the use of a ventricular assisted device or extracorporeal membrane oxygenation from January 2002 to August 2008. There were 32 (72.7%) males and their mean age was 61.7$\pm$14.9(range: 20$\sim$73) years old. The mean duration of extracorporeal life support system was 5.3$\pm$3.0 (range: 1$\sim$12) days. Result: Of these 44 patients, 24 (54.5%) patients were successfully weaned from the extracorporeal device. Eighteen (40.9%) survivors were able to be discharged from the hospital. Complications were noted in 38 patients (86.4%). An emergency operation, no usage of a concomitant intraaortic balloon pump and major complications during use of the extra corporeal life support system such as bleeding, flow instability and renal failure were identified as significant risk factors for poor survival on univariated analysis. Owing to educational support and a continuous renal replacement therapy system, the clinical outcomes of these patients have improved since 2006. On multivariated analysis, renal failure and bleeding during extracorporeal life support were significant risk factors for poor survival. Conclusion: Although using. extracorporeal life support systems after adult cardiovascular surgery revealed acceptable clinical results, determining the optimal treatment strategy and further well designed larger studies are needed to improve the survival rate of patients who undergo extracorporeal life support after adult cardiovascular surgery.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.1
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• pp.94-131
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• 2007

A review on the papers published in the Korean Journal of Air-Conditioning and Refrigerating Engineering in 2004 and 2005 has been done. Focus has been put on current status of research in the aspect of heating, cooling, air-conditioning, ventilation, sanitation and building environment. The conclusions are as follows. (1) Most of fundamental studies on fluid flow were related with heat transportation of facilities. Drop formation and rivulet flow on solid surfaces were interesting topics related with condensation augmentation. Research on micro environment considering flow, heat, humidity was also interesting for comfortable living environment. It can be extended considering biological aspects. Development of fans and blowers of high performance and low noise were continuing topics. Well developed CFD and flow visualization(PIV, PTV and LDV methods) technologies were widely applied for developing facilities and their systems. (2) The research trends of the previous two yews are surveyed as groups of natural convection, forced convection, electronic cooling, heat transfer enhancement, frosting and defrosting, thermal properties, etc. New research topics introduced include natural convection heat transfer enhancement using nanofluid, supercritical cooling performance or oil miscibility of $CO_2$, enthalpy heat exchanger for heat recovery, heat transfer enhancement in a plate heat exchanger using fluid resonance. (3) The literature for the last two years($2004{\sim}2005$) is reviewed in the areas of heat pump, ice and water storage, cycle analysis and reused energy including geothermal, solar and unused energy). The research on cycle analysis and experiments for $CO_2$ was extensively carried out to replace the Ozone depleting and global warming refrigerants such as HFC and HCFC refrigerants. From the year of 2005, the Gas Engine Heat Pump(GHP) has been paid attention from the viewpoint of the gas cooling application. The heat pipe was focused on the performance improvement by the parametric analysis and the heat recovery applications. The storage systems were studied on the performance enhancement of the storage tank and cost analysis for heating and cooling applications. In the area of unused energy, the hybrid systems were extensively introduced and the life cycle cost analysis(LCCA) for the unused energy systems was also intensively carried out. (4) Recent studies of various refrigeration and air-conditioning systems have focused on the system performance and efficiency enhancement. Heat transfer characteristics during evaporation and condensation are investigated for several tube shapes and of alternative refrigerants including carbon dioxide. Efficiency of various compressors and expansion devices are also dealt with for better modeling and, in particular, performance improvement. Thermoelectric module and cooling systems are analyzed theoretically and experimentally. (5) According to the review of recent studies on ventilation systems, an appropriate ventilation systems including machenical and natural are required to satisfied the level of IAQ. Also, an recent studies on air-conditioning and absorption refrigeration systems, it has mainly focused on distribution and dehumidification of indoor air to improve the performance were carried out. (6) Based on a review of recent studies on indoor environment and building service systems, it is noticed that research issues have mainly focused on optimal thermal comfort, improvement of indoor air Quality and many innovative systems such as air-barrier type perimeter-less system with UFAC, radiant floor heating and cooling system and etc. New approaches are highlighted for improving indoor environmental condition as well as minimizing energy consumption, various activities of building control and operation strategy and energy performance analysis for economic evaluation.

• Radiation Oncology Journal
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• v.21 no.4
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• pp.253-260
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• 2003

Purpose: No general consensus has been reached regarding the necessity of postoperative radiation therapy (PORT) and the optimal techniques of its application for patients with chest wall invasion (pT3cw) and node negative (NO) non-small cell lung cancer (NSCLC). We retrospectively analyzed the PT3cwN0 NSCLC patients who received PORT because of presumed inadequate resection margin on surgical findings. Materials and Methods: From Aug. 1994 till June 2000, 21 pT3cwN0 NSCLC patients received PORT at Samsung Medical Center; all of whom underwent curative on-bloc resection of the primary tumor plus the chest wall and regional lymph node dissection. PORT was typically stalled 3 to 4 weeks after operation using 6 or 10 MV X-rays from a linear accelerator. The radiation target volume was confined to the tumor bed plus the immediate adjacent tissue, and no regional lymphatics were included. The planned radiation dose was 54 Gy by conventional fractionation schedule. The survival rates were calculated and the failure patterns analyzed. Results: Overall survival, disease-free survival, loco-regional recurrence-free survival, and distant metastases-free survival rates at 5 years were 38.8$\%$, 45.5$\%$, 90.2$\%$, and 48.1$\%$, respectively. Eleven patients experienced treatment failure: six with distant metastases, three with intra-thoracic failures, and two with combined distant and intra-thoracic failures. Among the five patients with intra-thoracic failures, two had pleural seeding, two had in-field local failures, and only one had regional lymphatic failure in the mediastinum. No patients suffered from acute and late radiation side effects of RTOG grade 3 or higher. Conclusion: The strategy of adding PORT to surgery to improve the probability, not only of local control but also of survival, was justified, considering that local control was the most important component in the successful treatment of pT3cw NSCLC patients, especially when the resection margin was not adequate. The incidence and the severity of the acute and late side effects of PORT were markedly reduced, which contributed to improving the patients' qualify of life both during and after PORT, without increasing the risk of regional failures by eliminating the regional lymphatics from the radiation target volume.

• Asia pacific journal of information systems
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• v.24 no.4
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• pp.443-472
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• 2014

To survive in the global competitive environment, enterprise should be able to solve various problems and find the optimal solution effectively. The big-data is being perceived as a tool for solving enterprise problems effectively and improve competitiveness with its' various problem solving and advanced predictive capabilities. Due to its remarkable performance, the implementation of big data systems has been increased through many enterprises around the world. Currently the big-data is called the 'crude oil' of the 21st century and is expected to provide competitive superiority. The reason why the big data is in the limelight is because while the conventional IT technology has been falling behind much in its possibility level, the big data has gone beyond the technological possibility and has the advantage of being utilized to create new values such as business optimization and new business creation through analysis of big data. Since the big data has been introduced too hastily without considering the strategic value deduction and achievement obtained through the big data, however, there are difficulties in the strategic value deduction and data utilization that can be gained through big data. According to the survey result of 1,800 IT professionals from 18 countries world wide, the percentage of the corporation where the big data is being utilized well was only 28%, and many of them responded that they are having difficulties in strategic value deduction and operation through big data. The strategic value should be deducted and environment phases like corporate internal and external related regulations and systems should be considered in order to introduce big data, but these factors were not well being reflected. The cause of the failure turned out to be that the big data was introduced by way of the IT trend and surrounding environment, but it was introduced hastily in the situation where the introduction condition was not well arranged. The strategic value which can be obtained through big data should be clearly comprehended and systematic environment analysis is very important about applicability in order to introduce successful big data, but since the corporations are considering only partial achievements and technological phases that can be obtained through big data, the successful introduction is not being made. Previous study shows that most of big data researches are focused on big data concept, cases, and practical suggestions without empirical study. The purpose of this study is provide the theoretically and practically useful implementation framework and strategies of big data systems with conducting comprehensive literature review, finding influencing factors for successful big data systems implementation, and analysing empirical models. To do this, the elements which can affect the introduction intention of big data were deducted by reviewing the information system's successful factors, strategic value perception factors, considering factors for the information system introduction environment and big data related literature in order to comprehend the effect factors when the corporations introduce big data and structured questionnaire was developed. After that, the questionnaire and the statistical analysis were performed with the people in charge of the big data inside the corporations as objects. According to the statistical analysis, it was shown that the strategic value perception factor and the inside-industry environmental factors affected positively the introduction intention of big data. The theoretical, practical and political implications deducted from the study result is as follows. The frist theoretical implication is that this study has proposed theoretically effect factors which affect the introduction intention of big data by reviewing the strategic value perception and environmental factors and big data related precedent studies and proposed the variables and measurement items which were analyzed empirically and verified. This study has meaning in that it has measured the influence of each variable on the introduction intention by verifying the relationship between the independent variables and the dependent variables through structural equation model. Second, this study has defined the independent variable(strategic value perception, environment), dependent variable(introduction intention) and regulatory variable(type of business and corporate size) about big data introduction intention and has arranged theoretical base in studying big data related field empirically afterwards by developing measurement items which has obtained credibility and validity. Third, by verifying the strategic value perception factors and the significance about environmental factors proposed in the conventional precedent studies, this study will be able to give aid to the afterwards empirical study about effect factors on big data introduction. The operational implications are as follows. First, this study has arranged the empirical study base about big data field by investigating the cause and effect relationship about the influence of the strategic value perception factor and environmental factor on the introduction intention and proposing the measurement items which has obtained the justice, credibility and validity etc. Second, this study has proposed the study result that the strategic value perception factor affects positively the big data introduction intention and it has meaning in that the importance of the strategic value perception has been presented. Third, the study has proposed that the corporation which introduces big data should consider the big data introduction through precise analysis about industry's internal environment. Fourth, this study has proposed the point that the size and type of business of the corresponding corporation should be considered in introducing the big data by presenting the difference of the effect factors of big data introduction depending on the size and type of business of the corporation. The political implications are as follows. First, variety of utilization of big data is needed. The strategic value that big data has can be accessed in various ways in the product, service field, productivity field, decision making field etc and can be utilized in all the business fields based on that, but the parts that main domestic corporations are considering are limited to some parts of the products and service fields. Accordingly, in introducing big data, reviewing the phase about utilization in detail and design the big data system in a form which can maximize the utilization rate will be necessary. Second, the study is proposing the burden of the cost of the system introduction, difficulty in utilization in the system and lack of credibility in the supply corporations etc in the big data introduction phase by corporations. Since the world IT corporations are predominating the big data market, the big data introduction of domestic corporations can not but to be dependent on the foreign corporations. When considering that fact, that our country does not have global IT corporations even though it is world powerful IT country, the big data can be thought to be the chance to rear world level corporations. Accordingly, the government shall need to rear star corporations through active political support. Third, the corporations' internal and external professional manpower for the big data introduction and operation lacks. Big data is a system where how valuable data can be deducted utilizing data is more important than the system construction itself. For this, talent who are equipped with academic knowledge and experience in various fields like IT, statistics, strategy and management etc and manpower training should be implemented through systematic education for these talents. This study has arranged theoretical base for empirical studies about big data related fields by comprehending the main variables which affect the big data introduction intention and verifying them and is expected to be able to propose useful guidelines for the corporations and policy developers who are considering big data implementationby analyzing empirically that theoretical base.