• Journal of Chest Surgery
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• v.38 no.11 s.256
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• pp.733-738
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• 2005

Background: The possibility of incomplete revascularization and development of flow competition after revascularization of the borderline lesion made the hybrid strategy as an option for complete revascularization. Material and Method: From January f998 to July 2004, 25 $(3.2\%)$ patients underwent hybrid revascularization among 782 total OPCAB procedures. Clinical results and angiographic patencies were evalulated. Percutaneous coronary intervention (PCI) was peformed before CABG in 8 patients and after CABG in 47 patients. Result: The causes of PCIs before CABG were to achieve complete revascularization with minimally invasive surgery (n=7) and emergent PCI for culprit lesion (n=1). The indications of PCIs after CABG were high possibility of flow competition in the borderline lesion of right coronary artery territory (n=8), diffuse atheromatous lesion preventing anastomosis of graft (n=5), severe calcified ascending aorta with no more arterial grafi available (n=3), and intramyocardial coronary lesion (n=1). Mean number of distal anastomoses was $2.3\pm1.0$. Mean number of lesions treated by PCI was $1.2\pm0.4$. There was no operative or procedure-related mortality. PCI-related complication was periprocedural myocardial infarction in one patient, and complications related to CABG were transient atrial fibrillation (n=5), perioperative myocardial infarction (n=1), and transient renal dysfunction (n=1). Early postoperative coronary angiography $(1.8{pm}1.6days)$ revealed $100\%$ patency rate of grafts (57/57). The stenosis occurred in one patient performed PCI before CABG, which was successfully treated with re-ballooning. During midterm follow-up (mean; $25{\pm}26$ months), 1 patient died of congestive heart failure. All survivors (n=24) accomplished follow-up coronary angiographics, which showed .all grafts (56/57) were patent except one string sign. In-stent restenosis was developed in 2 patients who received bare metal stents. Conclusion: In selected patients, complete revascularization was achieved with low risk by taking the hybrid strategy.

• Journal of Chest Surgery
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• v.40 no.5 s.274
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• pp.341-350
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• 2007

Background: We present here the early and midterm surgical results for infective endocarditis and we especially focus on the effect of aggressive reconstruction or root implantation after wide debridement. Material and Method: Between January 1995 and Jun 2006, we enrolled 79 adult infective endocarditis patients who underwent surgical treatment. There were 63 and 16 native and prosthetic valve endocarditis cases, respectively. They included 27 cases of culture negative endocarditis. With performing valve replacement or repair, 28 of the patient underwent a more aggressive surgical option, for example, aortic root replacement or reconstruction, or heart base reconstruction etc. Result: There were statistical relationships between the in-hospital mortality and staphylococcal infection, urgent-based operation and operation during the active phase of endocarditis. Wide debridement and aggressive reconstruction were not related to either the post operative mortality or the early morbidity. Culture negative endocarditis was not related to the postoperative mortality and morbidity. Conclusion: Physicians must pay attention to patients' medical treatment during the preoperative period of the infective endocarditis. If surgery is considered for treating infective endocarditis, it should be performed before the downhill course of the disease so that the surgical outcome is improved. Wide debridement and more aggressive reconstruction are also warranted.

• Journal of Chest Surgery
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• v.40 no.11
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• pp.745-751
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• 2007

Background: Mediastinoscopy is generally performed to confirm mediastinal lymph node metastasis in lung cancer patients. It still remains controversial whether mediastinoscopy should be performed in all patients with resectable non-small cell lung cancer (NSCLC). We studied the clinical value of mediastinoscopy in preoperative staging in NSCLC. Material and Method: We retrospectively studied 90 NSCLC patients who underwent radiological evaluation and mediastinoscopy followed by surgical resection from March 2002 to December 2004. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of each evaluation method were assessed and compared. Result: Specificity, PPV, NPV, and accuracy of mediastinoscopy were superior to those of radiological evaluation, but there was no significant difference in sensitivity. The sensitivity of mediastinoscopy was 28.6% in 62 patients with radiological N0/1 disease and 72.7% in 28 patients with radiological N2/3 disease. Seven of eight patients in whom positive nodes were not detected by the mediastinoscopy had subcarinal lymph node metastasis. Conclusion: Considering its invasiveness, the difficulty to reach certain node stations, and its low sensitivity in radiological N0/1 disease, mediastinoscopy should be selectively performed in radiological N2/3 disease rather than in all radiological cancer stages.

• Archives of design research
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• v.17 no.1
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• pp.211-220
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• 2004

The Chaos theory of complexity and Fractal theory which became a prominent figure as a new paradigm of natural science should be understood not as whole, and not into separate elements of nature. Fractal Dimensions are used to measure the complexity of objects. We now have ways of measuring things that were traditionally meaningless or impossible to measure. They are capable of describing many irregularly shaped objects including man and nature. It is compatible method of application to express complexity of nature in the dimension of non-fixed number by placing our point of view to lean toward non-linear, diverse, endless time, and complexity when we look at our world. Fractal Dimension allows us to measure the complexity of an object. Having a wide application of fractal geometry and Chaos theory to the art field is the territory of imagination where art and science encounter each other and yet there has not been much research in this area. The formative word has been extracted in this study by analyzing objective data to grasp formative principle and geometric characteristic of (this)distinct figures of Fractals. With this form of research, it is not so much about fractal in mathematics, but the concept of self-similarity and recursiveness, randomness, devices expressed from unspeakable space, and the formative similarity to graphic design are focused in this study. The fractal figures have characteristics in which the structure doesn't change the nature of things of the figure even in the process if repeated infinitely many times, the limit of the process produces is fractal. Almost all fractals are at least partially self-similar. This means that a part of the fractal is identical to the entire fractal itself even if there is an enlargement to infinitesimal. This means any part has all the information to recompose as whole. Based on this scene, the research is intended to examine possibility of analysis of fractals in geometric characteristics in plasticity toward forms in graphic design. As a result, a beautiful proportion appears in graphic design with calculation of mathematic. It should be an appropriate equation to express nature since the fractal dimension allows us to measure the complexity of an object and the Fractla geometry should pick out high addition in value of peculiarity and characteristics in the complex of art and science. At the stage where the necessity of accepting this demand and adapting ourselves to the change is gathering strength is very significant in this research.

• Maritime Security
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• v.1 no.1
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• pp.215-240
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• 2020

In 2017, the U.S. DARPA coined 'mosaic warfare' as a new way of warfighting. According to the Timothy Grayson, director of DARPA's Strategic Technologies Office, mosaic warfare is a "system of system" approach to warfghting designed around compatible "tiles" of capabilities, rather than uniquely shaped "puzzle pieces" that must be fitted into a specific slot in a battle plan in order for it to work. Prior to cover mosaic warfare theory and recent development, it deals analyze its background and several premises for better understanding. The U.S. DoD officials might acknowledge the current its forces vulnerability to the China's A2/AD assets. Furthermore, the U.S. seeks to complete military superiority even in other nation's territorial domains including sea and air. Given its rapid combat restoration capability and less manpower casualty, the U.S. would be able to ready to endure war of attrition that requires massive resources. The core concept of mosaic warfare is a "decision centric warfare". To embody this idea, it create adaptability for U.S. forces and complexity or uncertainty for the enemy through the rapid composition and recomposition of a more disag g reg ated U.S. military force using human command and machine control. This allows providing more options to friendly forces and collapse adversary's OODA loop eventually. Adaptable kill web, composable force packages, A.I., and context-centric C3 architecture are crucial elements to implement and carry out mosaic warfare. Recently, CSBA showed an compelling assessment of mosaic warfare simulation. In this wargame, there was a significant differences between traditional and mosaic teams. Mosaic team was able to mount more simultaneous actions, creating additional complexity to adversaries and overwhelming their decision-making with less friendly force's human casualty. It increase the speed of the U.S. force's decision-making, enabling commanders to better employ tempo. Consequently, this article finds out and suggests implications for Korea armed forces. First of all, it needs to examine and develop 'mosaic warfare' in terms of our security circumstance. In response to future warfare, reviewing overall force structure and architecture is required which is able to compose force element regardless domain. In regards to insufficient defense resources and budget, "choice" and "concentration" are also essential. It needs to have eyes on the neighboring countries' development of future war concept carefully.

• Journal of Chest Surgery
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• v.42 no.3
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• pp.331-336
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• 2009

Background: Open surgical repair of abdominal aortic aneurysms was initiated by Dubost in 1952. Despite the rapid expansion of percutaneous endovascular repair, open surgical repair is still recognized for curative intent. We retrospectively analyzed surgical outcome, complications, and mortality-related factors for patients with abdominal aortic aneurysms over a 6 year period. Material and Method: We analyzed 18 patients who underwent surgery for abdominal aortic aneurysms between March 2002 and March 2008. The indications for surgery were rupture, a maximal aortic diameter >60 mm, medically intractable hypertension, or pain. Result: The mean age was $66.6{\pm}9.3$ years (range, $49\sim81$ years). Twelve patients (66.7%) were males a 6 patients were females. Extension of the aneurysm superior to the renal artery existed in 6 patients (33.3%), and extension to the iliac artery existed in 13 patients (72.2%). Five patients (27.8%) had ruptured aortic aneurysms. The mean maximal diameter of the aorta was $72.2{\pm}12.9$ mm (range, $58\sim109$ mm). Surgery was performed by a midline laparotomy, and 6 patients underwent emergency surgery. The mean total ischemic time from aorta clamping to revascularization was $82{\pm}42$ minutes (range, $35\sim180$ minutes). The mortality rate was 16.7%; the mortality rate for patients with ruptured aneurysms was 60%, and the mortality rate for patients with unruptured aneurysms was 0%. The postoperative complications included one each of renal failure, femoral artery and vein occlusion, and wound infection. The patients who were discharged had a long-term survival of $34{\pm}26$ months (range, $4\sim90$ months). Rupture and emergency surgery had a statistically significant mortality-related factor (p < 0.05). Conclusion: Emergency surgery for ruptured aortic aneurysms continues to have a high mortality, but unruptured cases are repaired with relative safety. Successfully operated patients had long-term survival. Even though endovascular aortic repair is the trend for abdominal aortic aneurysms, aggressive application should be determined with care. Experience and systemic support of each center is important in the treatment plan.

• Tuberculosis and Respiratory Diseases
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• v.46 no.4
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• pp.500-511
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• 1999

Background: Noninvasive positive pressure ventilation (NPPV) using facial or nasal mask have been widely used for several years in stable patients with chronic neuromuscular disease or central alveolar hypoventilation, and recently have been tried in patients with acute respiratory failure. In a few studies, NPPV was also used to rescue the patients with post-extubation respiratory failure. However, yet it has not been adopted as a weaning method in patients on long-term mechanical ventilation. So we performed this prospective clinical study to evaluate the usefulness of NPPV as a weaning method after removing endotracheal tube intentionally in patients on long-term mechanical ventilation. Method: Twelve patients who had been on invasive mechanical ventilation over 10 days were enrolled and 14 trials of NPPV were done. All had failed at least one weaning trial and showed ventilator dependence(pressure support requirement between 8-15cm $H_2O$, and PEEP requirement between 5-10cm $H_2O$), so tracheostomy was being considered. After removing the endotracheal tube, NPPV was applied using facial mask. Respiratory rate, arterial blood gas, pressure support level, and PEEP level were monitored just before intended extubation, at 30 minutes, 1 to 6, 6 to 12, 12 to 24 hours, 2nd day, and 3rd day following initiation of NPPV, and just before weaning from NPPV. The successful weaning was defined as spontaneous breathing off the ventilator for 48 hours or longer without respiratory distress. Results: The weaning through NPPV after intended extubation was successful in 7(50%) of 14 trials, and tracheostomy could be avoided in them. There were no differences in age, sex, APACHE III score, duration of invasive mechanical ventilation, baseline respiratory rate, $PaCO_2$ $PaO_2/FiO_2$, and ventilatory requirement(PS and PEEP) between the success and failure groups. In the success group, respiratory rate, pH, $PaCO_2$, and $PaO_2/FiO_2$ were not different between invasive MV and NPPV period. But in the failure group, pH decreased after 30 minutes of NPPV initiation compared with that of invasive MV($7.40\pm0.08$ vs. $7.34\pm0.06$, p<0.05). The causes of failure were worsening of ABG(n=3), retained tracheal secretion(n=2), mask intolerance(n=1), and flail chest(n=1). Conclusion: NPPV may be worth trying as a bridge method in weaning patients on long-term invasive mechanical ventilation.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.3
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• pp.88-99
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• 2018

After UNESCO appointed Royal Tombs of the Joseon Dynasty to be World Cultural Heritages(2009), Cultural Heritage Administration in Korea established Management Office of Royal Tombs of the Joseon Dynasty(2012) and conducted Mid to Long-Term Plan on Conservation, Management, Utilization of World Heritage 'Royal Tombs of the Joseon Dynasty(2015)'. The report, as an implementation plan, provides detailed contents of the maintenance planning of Royal Tombs of the Joseon Dynasty. From this background, with a view to comprehending the characteristics of the maintenance planning of trees in historical landscape forests, this study extracted the contents related to the historical landscape forests of the 40 Royal Tombs of the Joseon Dynasty from the "Mid to Long-term Plan" and conducted literature research. The results of the study are as follows. First, from 2016, the short-term plans have provided detailed contents on logging, transplanting and planting trees in the plans divided by stages. On the other hand, the long-term plans, instead of presenting abstract contents repeatedly for each royal tomb, should seek vegetation landscape that each royal tomb should aim for. Second, since the areas that are in charge of the various functions of the royal tombs have been subjects to the maintenance planning, it is effective to establish a maintenance planning by separating functional areas instead of the comprehensive concept as historical landscape forests. Third, the maintenance planning of trees in historical landscape forest of the Royal Tombs of Joseon Dynasty is based on daily management such as density control and maintaining the shape of trees, which is necessary to sustain the forest. Also, due to the goal of preserving the pine forest, which is recognized as a prototype vegetation landscape, foreign species and other trees have been more cut down. With a few limited types of tall tree but few shrubs and flowers, it is characterized that the orientation toward aesthetic landscapes is insufficient in large green spaces. Fourth, according to the function of the tomb, it is divided into entrance area, ceremonial area, burial area and outer forest, and the contents of the maintenance planning are analyzed by basic conditions of tree management: prototype, ecology, functionality, and aesthetics. After studying the tree management characteristics of each area, four suggestions are made: understanding the diversity of trees that form prototype landscape as a management plan, sustainability of various forests adapted to ecological environment, convenience required in addition to ceremony and safety characterizing the Royal Tombs of Joseon Dynasty, and the necessity of access to aesthetic landscape on the tombs.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.655-662
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• 2010

Background: Despite the rapid expansion of percutaneous endovascular repair, open surgical repair is still recognized as an option to achieve a cure. We retrospectively analyzed over a 6 year period the surgical outcomes, the complications and the mortality-related factors for patients with abdominal aortic aneurysms. Material and Method: We analyzed 36 patients who underwent surgery for abdominal aortic aneurysms between May 2001 and June 2005, and between April 2007 and November 2009. The indications for surgery were rupture, a maximal aortic diameter > 50 mm, and medically intractable hypertension or pain. Result: The mean patient age was $69.67{\pm}6.97$ years (range: 57 to 84 years). Thirty two patients (88.9%) were males and 4 patients (11.1%) were females. Extension to the iliac artery existed in 28 patients (77.8%). Thirteen patients (36.1%) had ruptured aortic aneurysms. The mean maximal diameter of the aorta was $73.7{\pm}13.3$ mm (60 to 100 mm). Surgery was performed by a midline laparotomy and 10 patients (27.8%) underwent emergency surgery. The mortality rate was 8.3%; the mortality rate for the patients with ruptured aneurysms was 23.1 % and the mortality rate for patients with unruptured aneurysms was 0%. The postoperative complications included wound infection (3 cases), sepsis (2 cases), renal failure (2 cases) and pneumonia (1 case). Unstable vital signs, pre-operative transfusion, ruptured aneurysm, emergency surgery, comorbidity (DM and syncope) and complications (sepsis and renal failure) were the statistically significant mortality-related factors (p < 0.05). Conclusion: Emergency surgery for ruptured aortic aneurysms continues to have high mortality, but the unruptured cases are repaired with relative safety. Even though endovascular aortic repair is the trend for abdominal aortic aneurysms, an elective operation of the unruptured aneurysms could decrease the procedure's morbidity and the inconvenient for repeat evaluation with good surgical results.

• Journal of Chest Surgery
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• v.31 no.11
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• pp.1070-1075
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• 1998

Background: With the advent of thoracoscopy, there has been increasing interest in less invasive surgical bullectomy and pleurodesis. The recurrence rate, however, has been reported higher in surgery with thoracoscopy than with open thoracotomy and it is thought to be caused by inappropriate mechanical pleurodesis during thoracoscopic surgery. Materials and methods: We compared the short-term recurrence rates according to the intensities of pleural abrasion in 62 patients who underwent VATS for treatment of spontaneous pneumothorax from April 1996 to August 1997. The patients were divided into 2 groups: group A(n=32) included patients who received relatively weak pleural abrasion using Endo-forcep instrument for grasping the gauze, and group B(n=30) received strong pleural abrasion using conventional instrument wrapped tightly with gauze. Each intensity of pleural abrasion allowed petechia on the parietal pleura in group A, and some tearing and bleeding in group B. Results: Indications for operation, sex distribution, and age were comparable in both groups. There were no differences in chest tube indwelling time(3.78±3.35 vs 3.80±2.49 days), hospital stay(4.72±1.87 vs 4.67±2.20 days), and the amount and duration of analgesics required postoperatively. Persistent air-leak more than 7 days after surgery occurred in 4/32(12.5%) and 2/30(6.7%) in group A and B, respectively. No bleeding-related complication occured. Pneumothorax recurred 12.5%(4/32) and 0%(0/30) of patients at a mean follow-up of 9.7 and 9.6 months in group A and B, respectively, and it was statistically significant(p<0.05). Conclusions: Proper intensity of pleural abrasion is very important factor to reduce recurrence after VATS for spontaneous pneumothorax. During short-term follow-upafter surgery, we could achieve excellent result in reducing recurrence rate with VATS and strong pleural abrasion which is comparable to thoracotomy.